全文获取类型
收费全文 | 195篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 31篇 |
金属工艺 | 1篇 |
机械仪表 | 10篇 |
建筑科学 | 5篇 |
能源动力 | 17篇 |
轻工业 | 15篇 |
水利工程 | 2篇 |
无线电 | 13篇 |
一般工业技术 | 24篇 |
冶金工业 | 33篇 |
原子能技术 | 30篇 |
自动化技术 | 17篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 1篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2016年 | 7篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 4篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有198条查询结果,搜索用时 62 毫秒
131.
Naveen Nagiah Uma Tiruchirapalli Sivagnanam Ranganathan Mohan Natarajan Tirupattur Srinivasan Praveen Kumar Sehgal 《Advanced Engineering Materials》2012,14(4):B138-B148
Electrospinning is a desired method to produce ultrathin fibers for tissue engineering. In order to mimic the nanofibrous structure of the extracellular matrix (ECM) poly(propylene carbonate) ultrathin fibers were electrospun using N,N‐dimethyl acetamide as solvent. Cationic surfactant, cetyl trimethyl ammonium bromide, was found to aid in the formation of beadless fibers of poly(propylene carbonate). Electrospinning parameters viz. concentration of polymer and that of the surfactant used as an additive, flow rate, electrostatic field, and effect of inner diameter of the needle were investigated and optimized. Scanning electron microscopy showed porous scaffold and fibers of diameter ranging from nano‐ to submicron range. FTIR spectroscopy and thermal analysis of the obtained fibers ensured the complete evaporation of solvent and optimal thermal stability of fibers for tissue engineering applications. The prepared fibers possess Young's modulus of 10.19 and 26.39 GPa with the tensile strengths of 22.11 and 21.29 MPa under dry and wet conditions, respectively. The fiber mat was measured to have a porosity of 48% and exhibited competent water retention capacity of 64%. Furthermore the scaffold was found to support the adhesion of mouse NIH 3T3 fibroblasts proving its mettle as a potential scaffold for tissue engineering applications. 相似文献
132.
133.
Babita Saini V. K. Sehgal M. L. Gambhir 《Structural and Multidisciplinary Optimization》2007,34(3):243-260
In this work, least-cost design of singly and doubly reinforced beams with uniformly distributed and concentrated load was
done by incorporating actual self-weight of beam, parabolic stress block, moment–equilibrium and serviceability constraint
besides other constraints. Also, this design expertise was incorporated into a genetically optimized artificial neural network
based on steepest descent, Levenberg–Marquardt, and quasi-Newton backpropagation learning techniques. The initial solution
for the optimization procedure was obtained using limit state design as per IS: 456-2000. 相似文献
134.
Arun K. Nayak Bal Raj Sehgal Armen V. Stepanyan 《Nuclear Engineering and Design》2006,236(19-21):2189-2198
The quenching characteristics of a volumetrically-heated particulate bed composed of radially stratified sand layers were investigated experimentally in the POMECO facility. The sand bed simulates the corium particulate debris bed which is formed when the molten corium released from the vessel fragments in water and deposits on the cavity floor during a postulated severe accident in a light water reactor (LWR). The electrically-heated bed was quenched by water from a water column established over top of it, and later also with water coming from its bottom, which was circulating from the water overlayer through downcomers. A series of experiments were conducted to reveal the effects of the size of downcomers, and their locations in the bed, on the quenching characteristics of the radially stratified debris beds. The downcomers were found to significantly increase the bed quenching rate. To simulate the non-condensable gases generated during the MCCI, air and argon were injected from the bottom of the bed at different flow rates. The effects of gas flow rate and its properties on the quenching behaviour were observed. The results indicate that the non-condensable gas flows reduce the quenching rate significantly. The gas properties also affect the quenching characteristics. 相似文献
135.
This paper presents the performance of an optimized collector system [1], employing light heat transfer oil as working fluid, operated in normal and reverse configurations under simulated solar conditions. Expressions for transient and stagnation temperatures of the working fluid have been derived. Experimental and theoretical values of efficiencies for different incident intensities show good agreement. The results indicate that shallow (10 mm) liquid stream results in more efficient solar thermal performance for the normal and the reverse configurations. 相似文献
136.
Using a finite-section model for bipolar transistors with current-dependent base resistance and gain, high-current asymptotic variations of base resistance, gain and effective emitter width are studied, and useful analytic formulas are presented. 相似文献
137.
BR Blazar PA Taylor A Panoskaltsis-Mortari S Sehgal DA Vallera 《Canadian Metallurgical Quarterly》1996,87(9):4001-4009
Rapamycin (RAPA) has been shown to be a highly effective means of reducing the lethality of graft-versus-host disease (GVHD) in B10.BR recipients of allogeneic C57BL/6 donor cells. RAPA-treated mice had no clinical (e.g., weight loss, diarrhea, lethargy) or histologic evidence of classical acute or chronic GVHD but did develop a clinical-pathological syndrome consisting of ulcerative dermatitis, bile duct proliferation, and a nondestructive peribronchiolar pulmonary infiltration. Because RAPA was found to interfere with the deletion of self-reactive T cells, we wondered whether the RAPA-induced syndrome was related to failed negative selection or altered alloreactivity. We now show that the RAPA-induced syndrome is due to effects on mature, donor-derived alloreactive T cells. By titering the number of T cells infused we were able to vary the syndrome incidence. In contrast to the syndrome seen after cyclosporin A (CsA) administration, the RAPA syndrome did not require an intact thymus and the disease could not be adoptively transferred. The addition of CsA (which blocks T-cell cytokine production) to RAPA (which blocks T-cell cytokine response) prevented the generation of this syndrome, suggesting that the tissue manifestations seen in RAPA only treated recipients were caused by cytokine production and release. RAPA also caused this alloimmune syndrome in recipients of minor histocompatibility antigen disparate donor cells, showing that the RAPA effects were not restricted to a single donor-recipient strain combination or to instances in which the donor and recipient were fully major histocompatibility complex disparate. We conclude that RAPA is a highly effective means of preventing murine acute GVHD, and that when combined with CsA, warrants consideration for human investigations. 相似文献
138.
We have tested the role of lectin-like interactions, with particular emphasis on CR3, in insoluble immune complex (IC)-mediated activation of human polymorphonuclear leukocytes (PMN). The ability of IC to trigger intracellular Ca2+ release and O2- production by normal PMN, saccharide-treated cells, and CR3-deficient PMN (leukocyte adhesion deficiency, LAD, patients) were tested. When indo-1-labeled normal PMN were stimulated with IC in Ca(2+)-free buffer, intracellular Ca2+ rose from approximately 100 nM to approximately 230 nM. However, when LAD PMN were tested, a small rise in intracellular Ca2+ was observed. Because previous studies have shown that certain saccharides inhibit CR3-Fc gamma RIII co-capping, we tested a panel of saccharides to determine their ability to influence IC-mediated intracellular Ca2+ release. When normal PMN were exposed to 0.15 M N-acetyl-D-glucosamine (NADG), D-mannose, or alpha-methyl-mannoside, the Ca2+ response to IC was significantly reduced. However, addition of 0.15 M glucose, raffinose, sucrose, galactose, fructose, or sorbitol did not significantly affect the Ca2+ response, suggesting that the response was specific for certain saccharides. To test the physiologic consequences of these Ca2+ signals, we have examined the ability of saccharides to influence O2- production by normal PMN and the ability of LAD PMN to produce O2- upon triggering by IC. Normal PMN stimulated with IC generated 4.3 +/- 1.7 nmol/10(6) cells/30 min of O2-. In contrast, O2- production was inhibited by 0 to 20% by glucose, galactose, sucrose, sorbitol, fructose, and raffinose and > or = 50% by NADG and mannose. LAD PMN, which display diminished Ca2+ signals, were found to produce O2- at 47 +/- 6% of control levels. NADG and mannose dose-response studies indicated that they cooperatively block O2-. 相似文献
139.
VN Sehgal DM Thappa RC Sharma S Jain SN Bhattacharya 《Canadian Metallurgical Quarterly》1993,20(1):56-58
Clozapine is an atypical agent for intractable schizophrenia which was introduced into the UK at the beginning of 1990. Its lack of extrapyramidal side effects and its action on negative symptoms single it out from conventional neuroleptics. This article describes the drug's development/special monitoring and dispensing arrangements, and gives advice on how it can best be utilized. 相似文献
140.
A low cost technique of spray pyrolysis has been described for the growth of black cobalt selective surfaces on commercially available aluminum and galvanized iron substrates. Parameters of growth have been optimized by a comparative analysis of opto-thermal, structural and optical properties of these films. Optimized films on aluminum were 0.21 μm thick and had α = 0.92 and 100°C = 0.13, Films on galvanized iron substrates gave best results (α=0.91, 100°C=0.12) for film thickness 0.24 μm. Accelerated life test studies indicate that these films have good adhesion to the substrates and are stable up to 220°C. 相似文献