全文获取类型
收费全文 | 717篇 |
免费 | 20篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 17篇 |
综合类 | 1篇 |
化学工业 | 133篇 |
金属工艺 | 10篇 |
机械仪表 | 19篇 |
建筑科学 | 35篇 |
矿业工程 | 3篇 |
能源动力 | 46篇 |
轻工业 | 32篇 |
水利工程 | 4篇 |
无线电 | 62篇 |
一般工业技术 | 176篇 |
冶金工业 | 74篇 |
原子能技术 | 10篇 |
自动化技术 | 121篇 |
出版年
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 23篇 |
2020年 | 19篇 |
2019年 | 25篇 |
2018年 | 30篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 12篇 |
2014年 | 31篇 |
2013年 | 64篇 |
2012年 | 31篇 |
2011年 | 43篇 |
2010年 | 34篇 |
2009年 | 25篇 |
2008年 | 19篇 |
2007年 | 27篇 |
2006年 | 23篇 |
2005年 | 20篇 |
2004年 | 15篇 |
2003年 | 24篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 12篇 |
1998年 | 16篇 |
1997年 | 9篇 |
1996年 | 13篇 |
1995年 | 6篇 |
1994年 | 17篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 10篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 2篇 |
1977年 | 7篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1971年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有743条查询结果,搜索用时 15 毫秒
1.
Investigation on the miniaturized parallel multichannel-based devices packed with glass beads to improve the mass exchange execution is the critical focal point of the current study. One of the essential parameters to specify the miniaturized devices' flow distribution is the residence time distribution (RTD). In the present context, the RTDs of a liquid tracer were investigated for the air-water multiphase flows (concurrent) across the multichannel-based miniaturized devices (comprising of 11 similar dimensional parallel channels). The devices were variable in height and packed with glass beads. The conductivity estimations generated the RTD curves and were addressed by the axial dispersion model (ADM). The fluid-flow rates differed within the range of 5–23 ml min−1. The axial dispersion coefficients and the rate of the specific energy dispersion were investigated. The effects of pressure difference and geometry on the hydrodynamic attributes and mixing properties were well-illustrated, and the new correlations were suggested. 相似文献
2.
Wireless Personal Communications - A dual purpose system is presented in this paper which serves not only as a door closer, but is equally effective for surveillance purposes. The currently... 相似文献
3.
4.
5.
In this present work, Ca-alginate-biochar adsorbent has been synthesized, characterized and tested its effectiveness in the removal of aqueous phase Zn2+ metal. The removal efficiency was studied under various physicochemical process parameters. External mass transfer model, intraparticle diffusion model and pseudo-first-order and pseudo-second-order models were used to fit the experimental Zn2+ adoption kinetic results and to identify the mechanism of adsorption. The desorption studies indicate the possibilities of ion-exchange and physical–chemical adsorption of Zn2+. The adsorption was best described by Langmuir isotherm model. Thermodynamic parameters suggested that the adsorption process becomes spontaneous, endothermic and irreversible in nature. 相似文献
6.
Ferrite particles coated with biocompatible phases can be used for hyperthermia treatment of cancer. We have synthesized substituted
calcium hexaferrite, which is not stable on its own but is stabilized with small substitution of La. Hexaferrite of chemical
composition (CaO)0.75(La203)0.20(Fe2O3)6 was prepared using citrate gel method. Hydroxyapatite was prepared by precipitating it from aqueous solution of Ca(NO3)2 and (NH4)2HPO4 maintaining pH above 11. Four different methods were used for coating of hydroxyapatite on ferrite particles. SEM with EDX
and X-ray diffraction analysis shows clear evidence of coating of hydroxyapatite on ferrite particles. These coated ferrite
particles exhibited coercive field up to 2 kOe, which could be made useful for hysteresis heating in hyperthermia. Studies
by culturing BHK-21 cells and WBC over the samples show evidence of biocompatibility. SEM micrographs and cell counts give
clear indication of cell growth on the surface of the sample. Finally coated ferrite particle was implanted in Kasaulli mouse
to test its biocompatibility. The magnetic properties and biocompatibility studies show that these hydroxyapatite coated ferrites
could be useful for hyperthermia. 相似文献
7.
The optical transmission of Tl3 As Se3 as a function of wavelength and temperature is reported for the 1.2 – 2.5 um spectral range, and at temperatures from 40 to 300K. The absorption edge for the material occurs at about 1.011 eV. The material also indicated direct transitions at about 1.015 eV and indirect transitions at about 1.001 eV. The direct and indirect transitions are found to be independent of temperature. Electrical measurements have identified the sample as p-type, with hole concentrations of 5 × 1015 and 6 × 1012 cm?3 at 395 and 300K, respectively. The sample seems to be a good insulator at all temperatures between 40 ?300K. 相似文献
8.
In this report, the role of 34 kDa HA-binding protein in hyaluronic acid-induced cellular signalling in lymphocytes has been examined. The binding of 125I-HA to lymphocytes in vivo was found to be inhibited by pre-incubation of the cells with anti-34 kDa HA-binding protein antibodies, thus confirming 34 kDa HA-binding protein as the specific HA-receptor in lymphocytes. This observation was substantiated by anti-34 kDa HA-binding protein antibodies immunoblotting and 125I-HA ligand blotting of lymphocytes cell lysate. The HA-induced cell aggregation, tyrosine phosphorylation and cytoskeletal protein phosphorylation demonstrate the HA-induced early cellular signalling events in lymphocytes. Further, to study the involvement of 34 kDa HA-binding protein in mitogen induced lymphocyte signalling, we studied in vivo phosphorylation and secondary messenger formation. The enhanced 34 kDa HA-binding protein phosphorylation by HA and the inhibition of cellular aggregation and IP3 formation by anti-HA-binding protein antibodies revealed that 34 kDa HA-binding protein is one of the potential mediators in HA-induced signal transduction. 相似文献
9.
A. Deb P. K. Banerjee 《International journal for numerical methods in engineering》1989,28(7):1539-1555
A comparison between a family of isoparametric C°-continucus elements in the context of two-dimensional elastostatics using the direct boundary element method is presented. The elements studied use Lagrangian shape functions of orders quadratic, cubic and quartic. The relative efficiencies of these elements from the viewpoint of accuracy of solution as well as cost effectiveness are examined through certain selected problems. It emerges from the present study that the quartic element is more reliable in accuracy than the lower members of the family without being necessarily more expensive. 相似文献
10.
Glaucio H. Paulino Ivan F. M. Menezes Marcelo Gattass Subrata Mukherjee 《International journal for numerical methods in engineering》1994,37(9):1511-1530
A Finite Element Graph (FEG) is defined here as a nodal graph (G), a dual graph (G*), or a communication graph (G˙) associated with a generic finite element mesh. The Laplacian matrix ( L (G), L (G*) or L (G˙)), used for the study of spectral properties of an FEG, is constructed from usual vertex and edge connectivities of a graph. An automatic algorithm, based on spectral properties of an FEG (G, G* or G˙), is proposed to reorder the nodes and/or elements of the associated finite element mesh. The new algorithm is called Spectral PEG Resequencing (SFR). This algorithm uses global information in the graph, it does not depend on a pseudoperipheral vertex in the resequencing process, and it does not use any kind of level structure of the graph. Moreover, the SFR algorithm is of special advantage in computing environments with vector and parallel processing capabilities. Nodes or elements in the mesh can be reordered depending on the use of an adequate graph representation associated with the mesh. If G is used, then the nodes in the mesh are properly reordered for achieving profile and wavefront reduction of the finite element stiffness matrix. If either G* or G˙ is used, then the elements in the mesh are suitably reordered for a finite element frontai solver, A unified approach involving FEGs and finite element concepts is presented. Conclusions are inferred and possible extensions of this research are pointed out. In Part II of this work,1 the computational implementation of the SFR algorithm is described and several numerical examples are presented. The examples emphasize important theoretical, numerical and practical aspects of the new resequencing method. 相似文献