全文获取类型
收费全文 | 931篇 |
免费 | 19篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 206篇 |
金属工艺 | 52篇 |
机械仪表 | 31篇 |
建筑科学 | 6篇 |
能源动力 | 33篇 |
轻工业 | 47篇 |
水利工程 | 7篇 |
石油天然气 | 3篇 |
无线电 | 70篇 |
一般工业技术 | 266篇 |
冶金工业 | 82篇 |
原子能技术 | 15篇 |
自动化技术 | 128篇 |
出版年
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 25篇 |
2020年 | 13篇 |
2019年 | 17篇 |
2018年 | 19篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 17篇 |
2014年 | 22篇 |
2013年 | 64篇 |
2012年 | 43篇 |
2011年 | 69篇 |
2010年 | 54篇 |
2009年 | 50篇 |
2008年 | 49篇 |
2007年 | 47篇 |
2006年 | 28篇 |
2005年 | 27篇 |
2004年 | 20篇 |
2003年 | 17篇 |
2002年 | 21篇 |
2001年 | 17篇 |
2000年 | 26篇 |
1999年 | 25篇 |
1998年 | 23篇 |
1997年 | 16篇 |
1996年 | 18篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有952条查询结果,搜索用时 15 毫秒
91.
Hypothalamic GABAergic activity and immune response in spleen were not significantly changed with the increase of age from 3 to 6 months in adult male albino rats. Further increase of age from 6 to 9 months increase the GABAergic activity and decreased the cell viability in spleen without any change in its T-lymphocyte cytotoxicity. Consumption of low protein diet (LPD) for a short-term period (STP; 7 consecutive days) increased the hypothalamic GABAergic activity without changing the immune response in 3 months old rats. When supplemented for a long-term period (LTP; 30 consecutive days) to 3 months old rats, a reduction of hypothalamic GABAergic activity and the immune response was observed. Intake of high protein diet (HPD) for both STP and LTP increased the GABAergic activity and immune response, but the increase of GABAergic activity in hypothalamus under STP was greater than that observed under LTP. In 6 months old rats consumption of LPD for STP reduced the GABAergic activity without any alteration of its immune response. Long-term supplementation of this LPD to the same age group increased GABAergic activity and the mitotic activity of spleen cells without any alteration of the functional activity of the T-cells in spleen. Consumption of HPD for STP failed to produce any change in hypothalamic GABAergic activity and the immune response of 6 months old rats. Supplementation of HPD for LTP reduced the hypothalamic GABAergic activity and the immune response of the same age group. The reduction in hypothalamic GABAergic activity without any change in the immune response was observed following the supplementation of low protein diet to 9 months old rat for STP. Intake of the LPD for LTP also reduced the hypothalamic GABAergic activity and the mitotic activity of the spleen cells without any alteration of the functional activity of the T-cells in spleen of 9 months old rats. Supplementation of HPD for STP to this aged rat, on the other hand, failed to produced any change in hypothalamic GABAergic activity and the immune response. Intake of HPD for LTP by this aged rats increased the hypothalamic GABAergic activity along with the immune response. The results of this study, thus, suggest that hypothalamic GABAergic activity during aging is an index of immune response and it is modulated following the short- and long-term consumption of protein poor and protein rich diet. 相似文献
92.
The effect of coagulants on the texture of chhana (an acid and heat coagulated product made from milk) 总被引:1,自引:0,他引:1
Mahuya Bandyopadhyay Runu Chakraborty & Utpal Raychaudhuri 《International Journal of Food Science & Technology》2005,40(8):799-810
Chhana (a heat and acid coagulated milk protein mass and an Indian equivalent to cottage cheese) can be used as a raw material for the manufacture of various types of sweets popular all over India. Texture Profile Analysis (TPA), using an Instron Universal Testing Machine, was used to determine the effect of different coagulants on the textural characteristics of chhana. Chhana was made using three different coagulants: citric acid, lactic acid and calcium lactate, at five different concentrations, 0.5, 1, 2, 4 and 8%. Two types of dilution media, distilled water and acid whey, were used. The textural characteristics obtained when aqueous 0.5% citric acid, aqueous 0.5% lactic acid and 4–8% calcium lactate solutions, using acid whey as the solvent, gave similar TPA readings to normal chhana. 相似文献
93.
G Bandyopadhyay ML Standaert L Galloway J Moscat RV Farese 《Canadian Metallurgical Quarterly》1997,138(11):4721-4731
We examined the question of whether insulin activates protein kinase C (PKC)-zeta in L6 myotubes, and the dependence of this activation on phosphatidylinositol (PI) 3-kinase. We also evaluated a number of issues that are relevant to the question of whether diacylglycerol (DAG)-dependent PKCs or DAG-insensitive PKCs, such as PKC-zeta, are more likely to play a role in insulin-stimulated glucose transport in L6 myotubes and other insulin-sensitive cell types. We found that insulin increased the enzyme activity of immunoprecipitable PKC-zeta in L6 myotubes, and this effect was blocked by PI 3-kinase inhibitors, wortmannin and LY294002; this suggested that PKC-zeta operates downstream of PI 3-kinase during insulin action. We also found that treatment of L6 myotubes with 5 microM tetradecanoyl phorbol-13-acetate (TPA) for 24 h led to 80-100% losses of all DAG-dependent PKCs (alpha, beta1, beta2, delta, epsilon) and TPA-stimulated glucose transport (2-deoxyglucose uptake); in contrast, there was full retention of PKC-zeta, as well as insulin-stimulated glucose transport and translocation of GLUT4 and GLUT1 to the plasma membrane. Unlike what has been reported in BC3H-1 myocytes, TPA treatment did not elicit increases in PKCbeta2 messenger RNA or protein in L6 myotubes, and selective retention of this PKC isoform could not explain the retention of insulin effects on glucose transport after prolonged TPA treatment. Of further interest, TPA acutely activated membrane-associated PI 3-kinase in L6 myotubes, and acute effects of TPA on glucose transport were inhibited, not only by the PKC inhibitor, LY379196, but also by both wortmannin and LY294002; this suggested that DAG-sensitive PKCs activate glucose transport through cross-talk with phosphatidylinositol (PI) 3-kinase, rather than directly through PKC. Also, the cell-permeable, myristoylated PKC-zeta pseudosubstrate inhibited insulin-stimulated glucose transport both in non-down-regulated and PKC-depleted (TPA-treated) L6 myotubes; thus, the PKC-zeta pseudosubstrate appeared to inhibit a protein kinase that is required for insulin-stimulated glucose transport but is distinct from DAG-sensitive PKCs. In keeping with the latter dissociation of DAG-sensitive PKCs and insulin-stimulated glucose transport, LY379196, which inhibits PKC-beta (preferentially) and other DAG-sensitive PKCs at relatively low concentrations, inhibited insulin-stimulated glucose transport only at much higher concentrations, not only in L6 myotubes, but also in rat adipocytes, BC3H-1 myocytes, 3T3/L1 adipocytes and rat soleus muscles. Finally, stable and transient expression of a kinase-inactive PKC-zeta inhibited basal and insulin-stimulated glucose transport in L6 myotubes. Collectively, our findings suggest that, whereas PKC-zeta is a reasonable candidate to participate in insulin stimulation of glucose transport, DAG-sensitive PKCs are unlikely participants. 相似文献
94.
ML Standaert L Galloway P Karnam G Bandyopadhyay J Moscat RV Farese 《Canadian Metallurgical Quarterly》1997,272(48):30075-30082
Insulin provoked rapid increases in enzyme activity of immunoprecipitable protein kinase C-zeta (PKC-zeta) in rat adipocytes. Concomitantly, insulin provoked increases in 32P labeling of PKC-zeta both in intact adipocytes and during in vitro assay of immunoprecipitated PKC-zeta; the latter probably reflected autophosphorylation, as it was inhibited by the PKC-zeta pseudosubstrate. Insulin-induced activation of immunoprecipitable PKC-zeta was inhibited by LY294002 and wortmannin; this suggested dependence upon phosphatidylinositol (PI) 3-kinase. Accordingly, activation of PI 3-kinase by a pYXXM-containing peptide in vitro resulted in a wortmannin-inhibitable increase in immunoprecipitable PKC-zeta enzyme activity. Also, PI-3,4-(PO4)2, PI-3,4,5-(PO4)3, and PI-4,5-(PO4)2 directly stimulated enzyme activity and autophosphoralytion in control PKC-zeta immunoprecipitates to levels observed in insulin-treated PKC-zeta immunoprecipitates. In studies of glucose transport, inhibition of immunoprecipitated PKC-zeta enzyme activity in vitro by both the PKC-zeta pseudosubstrate and RO 31-8220 correlated well with inhibition of insulin-stimulated glucose transport in intact adipocytes. Also, in adipocytes transiently expressing hemagglutinin antigen-tagged GLUT4, co-transfection of wild-type or constitutive PKC-zeta stimulated hemagglutinin antigen-GLUT4 translocation, whereas dominant-negative PKC-zeta partially inhibited it. Our findings suggest that insulin activates PKC-zeta through PI 3-kinase, and PKC-zeta may act as a downstream effector of PI 3-kinase and contribute to the activation of GLUT4 translocation. 相似文献
95.
Processing of Piezocomposites by Fused Deposition Technique 总被引:1,自引:0,他引:1
Amit Bandyopadhyay Raj K. Panda Victor F. Janas Mukesh K. Agarwala Stephen C. Danforth Ahmad Safari 《Journal of the American Ceramic Society》1997,80(6):1366-1372
Piezoelectric ceramic/polymer composites were made by a fused deposition (FD) technique, which is a solid-freeform fabrication (or layered manufacturing) technique where three-dimensional (3-D) objects are built layer by layer from a computer-aided design (CAD) file on a computer-controlled fixtureless platform. Indirect and direct FD methods were used to fabricate lead zirconate titanate (PZT)/polymer composites. For the indirect method, a CAD file for the negative image of the final part was created. A polymer mold was made via FD using a thermoplastic filament, and composite formation was completed via a lost mold technique. In the direct FD method, a thermoplastic polymeric filament that was filled with 50–55 vol% of PZT powder was used to form a positive image of the desired structure. Three-dimensional honeycomb ("3-D honeycomb") composites and "ladder" composites with 3-3 connectivity, which were formed via the FD technique, showed excellent electromechanical properties for transducer applications. In addition, the FD technique showed the ability to form composites with controlled phase periodicity, various volume fractions, and a variety of microstructures and macrostructures that are not possible with traditional composite-forming techniques. 相似文献
96.
Ravindra Kumar Shirsendu Banerjee Anirban Banik Tarun Kanti Bandyopadhyay 《Petroleum Science and Technology》2017,35(6):615-624
The effect of diameter, velocity, and temperature on flow properties of heavy crude oil in three horizontal pipelines using computational fluid dynamics (CFD) was studied. The flow characteristics were simulated by using CFD software, ANSYS Fluent 6.2. The mesh geometry of the pipelines having inner diameter of 1, 1.5, and 2 inch were created by using Gambit 2.4.6. From grid independent study, 221, 365 mesh sizes were selected for simulation. The CFD ANSYS Fluent 6.2 Solver predicted the flow phenomena, pressure, pressure drop, wall shear stress, shear strain rate, and friction factor. A good agreement between experimental and CFD simulated values was obtained. 相似文献
97.
K. Ashok G. K. Mandal D. Bandyopadhyay 《Transactions of the Indian Institute of Metals》2015,68(1):9-18
Deoxidation of liquid steel involves consumption of high energy materials like ferro alloys and generation of deoxidation products which could be entrapped into liquid steel as non-metallic inclusions. The present investigation is focused on deoxidation of liquid steel, considering mainly aluminium and silicon as deoxidizer. A simple and realistic mathematical model of deoxidation of liquid steel has been developed based on the thermodynamic principles and material balance approach for day to day industrial practice. One of the main aims of the theoretical study was to predict the amount of deoxidizers required for a given steel composition. A methodology has also been developed to predict the stability of different oxides expected to be present in liquid steel after deoxidation. Model predictions have been compared with the industrial data as well as results obtained from commercial thermodynamic software package FactSage 6.4, simulated under identical conditions. Model predictions are in reasonable agreement with the ferro alloy consumption in industrial steelmaking processes. 相似文献
98.
Sunil C Shanbhag AA Nandy M Bandyopadhyay T Tripathy SP Lahiri C Joshi DS Sarkar PK 《Radiation protection dosimetry》2011,143(1):4-11
The directional distribution of the ambient neutron dose equivalent from 145-MeV (19)F projectiles bombarding a thick aluminium target is measured and analysed. The measurements are carried out with a commercially available dose equivalent meter at 0°, 30°, 60° and 90° with respect to the beam direction. The experimental results are compared with calculated doses from EMPIRE nuclear reaction code and different empirical formulations proposed by others. The results are also compared with the measured data obtained from an earlier experiment at a lower projectile energy of 110 MeV for the same target-projectile combination. 相似文献
99.
Soumen Pal A. K. Bandyopadhyay S. Mukherjee B. N. Samaddar P. G. Pal 《Bulletin of Materials Science》2011,34(4):859-864
Although existence of MgAl2O4-γ-Al2O3 solid solution has been reported in the past, the detailed interactions have not been explored completely. For the first
time, we report here a mathematical framework for the detailed solid solution interactions of γ-Al2O3 in MgAl2O4 (spinel). To investigate the solid solubility of γ-Al2O3 in MgAl2O4, Mg-Al spinel (MgO-nAl2O3; n = 1, 1.5, 3, 4.5 and an arbitrary high value 30) precursors have been heat treated at 1000°C. Presence of only non-stoichiometric
MgAl2O4 phase up to n = 4.5 at 1000°C indicates that alumina (as γ-Al2O3) present beyond stoichiometry gets completely accommodated in MgAl2O4 in the form of solid solution. γ → α alumina phase transformation and its subsequent separation from MgAl2O4 has been observed in the Mg-Al spinel powders (n > 1) when the 1000°C heat treated materials are calcined at 1200°C. In the mathematical framework, unit cell of MgAl2O4 (Mg8Al16O32) has been considered for the solid solution interactions (substitution of Mg2+ ions by Al3+ ions) with γ-Al2O3. It is suggested that combination of unit cells of MgAl2O4 takes part in the interactions when n > 5 (MgO-nAl2O3). 相似文献
100.
In this paper, a methodology is proposed to determine the design space for synthesis, analysis, and optimization of solar water heating systems. The proposed methodology incorporates different design constraints to identify all possible designs or a design space on a collector area vs. storage volume diagram. The design space is represented by tracing constant solar fraction lines on a collector area vs. storage volume diagram. It has been observed that there exists a minimum as well as a maximum storage volume for a given solar fraction and collector area. Similarly existence of a minimum and a maximum collector area is also observed for a fixed solar fraction and storage volume. For multi-objective optimization, a Pareto optimal region is also identified. Based on the identified design space, the solar water heating system is optimized by minimizing annual life cycle cost. Due to uncertainty in solar insolation, system parameters and cost data, global optimization may not be utilized to represent a meaningful design. To overcome this, a region of possible design configurations is also identified in this paper. 相似文献