全文获取类型
收费全文 | 1818篇 |
免费 | 60篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 60篇 |
综合类 | 4篇 |
化学工业 | 411篇 |
金属工艺 | 53篇 |
机械仪表 | 30篇 |
建筑科学 | 93篇 |
矿业工程 | 18篇 |
能源动力 | 40篇 |
轻工业 | 284篇 |
水利工程 | 15篇 |
石油天然气 | 3篇 |
无线电 | 84篇 |
一般工业技术 | 272篇 |
冶金工业 | 278篇 |
原子能技术 | 13篇 |
自动化技术 | 222篇 |
出版年
2022年 | 18篇 |
2021年 | 34篇 |
2020年 | 17篇 |
2019年 | 19篇 |
2018年 | 36篇 |
2017年 | 21篇 |
2016年 | 47篇 |
2015年 | 45篇 |
2014年 | 41篇 |
2013年 | 69篇 |
2012年 | 52篇 |
2011年 | 85篇 |
2010年 | 67篇 |
2009年 | 56篇 |
2008年 | 66篇 |
2007年 | 76篇 |
2006年 | 40篇 |
2005年 | 52篇 |
2004年 | 39篇 |
2003年 | 39篇 |
2002年 | 35篇 |
2001年 | 30篇 |
2000年 | 27篇 |
1999年 | 34篇 |
1998年 | 63篇 |
1997年 | 45篇 |
1996年 | 37篇 |
1995年 | 29篇 |
1994年 | 27篇 |
1993年 | 30篇 |
1992年 | 27篇 |
1991年 | 28篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 18篇 |
1985年 | 27篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 21篇 |
1981年 | 13篇 |
1980年 | 18篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1977年 | 24篇 |
1976年 | 17篇 |
1975年 | 25篇 |
1974年 | 15篇 |
1973年 | 15篇 |
排序方式: 共有1880条查询结果,搜索用时 15 毫秒
101.
Thermally excited vibrations of composite viscoelastic two-layer beams with interfacial slip are analyzed. Geometrically linearized conditions are considered, and the Bernoulli-Euler hypothesis is applied to each layer. At the interface a linear viscoelastic slip law is assigned. The resulting sixth-order initial boundary value problem of the deflection is solved in the time domain by separating the dynamic response in a quasistatic and a complementary dynamic portions. The quasistatic solution is determined in closed form, and the remaining complementary dynamic part is approximated by a truncated modal series that exhibits accelerated convergence. Numerical results are obtained for single-span composite beams with interlayer slip by means of a time-stepping procedure based on the linear interpolation of the driving terms within the time intervals. 相似文献
102.
Caspar Franz; Silberschatz George; Goldfried Marvin; Watson Jeanne C. 《Canadian Metallurgical Quarterly》2010,20(1):101
In this article, each author gives a brief comment on similarities he or she sees throughout the case formulations captured in the articles by Watson (2010a), Silberschatz (2010), Goldfried (2010), and Caspar (2010). A systematic comparison is added. Overall, the impression is confirmed and maintained that if authors are ready to renounce the use of the jargon of their specific approach, many similarities can be found. There are nevertheless differences that would lead us to expect a different course of therapy and different effects beyond the main effect of recovery in the case of David, pursuing the conceptualization and interventions proposed by Watson (2010b). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
Electrochemical characterization of electrolytes for lithium-ion batteries based on lithium difluoromono(oxalato)borate 总被引:1,自引:0,他引:1
Sandra ZugmannDominik Moosbauer Marius AmerellerChristian Schreiner Franz WudyRené Schmitz Raphael SchmitzPhilipp Isken Christian DippelRomek Müller Miriam KunzeAlexandra Lex-Balducci Martin WinterHeiner Jakob Gores 《Journal of power sources》2011,196(3):1417-1424
The salt lithium difluoromono(oxalato)borate (LiDFOB) showed some promising results for lithium-ion-cells. It was synthesized via a new synthetic route that avoids chloride impurities. Here we report the properties of its solutions (solvent blend ethylene carbonate/diethyl carbonate (3:7, mass ratio), including its conductivity, cationic transference number, hydrolysis, Al-current collector corrosion-protection ability and its cycling performance with some electrode materials. Some Al-corrosion studies were also performed with the help of our recently developed computer controlled impedance scanning electrochemical quartz crystal microbalance (EQCM) that proofed to be a useful tool for battery material investigations. 相似文献
104.
105.
106.
107.
108.
Anvar R. Kacimov Franz Marketz Tasneem Pervez 《Journal of Petroleum Science and Engineering》2009,64(1-4):67-76
Steady, one-phase, plane and axisymmetric, Darcian seepage in a homogeneous rock adjacent to a partly isolated wellbore with annular seals is analytically studied. Water flows from an isobaric feeding contour and a fracture, which is kept at the same pressure as the feeding contour, to a wellbore. Partial isolation of the wellbore makes its wall a composition of intermittently arrayed no-flow boundaries, which model the wellbore seals, and isobaric surfaces, which model the annular compartments between the seals and a wellbore tubular on which the seals are mounted. Pressure drops from the aquifer (fracture) to the compartments and further to the borehole that generates a hierarchy of flows mathematically equivalent to the Toth [Freeze, R.A., Cherry, J.A., 1979. Groundwater. Prentice Hall, Englewood Cliffs] hydrogeological patterns of regional, intermediate and local groundwater flows on the scale of catchments. Conformal mappings of complex potential domains onto physical planes, where water seepage takes place, are used to tackle the fragments of the full feeding contour-fracture–sealed wellbore system. Explicit rigorous solutions for the flow characteristics (pressure and stream function) enable calculating optimal wellbore isolation with a criterion of minimal water flow rate from the fracture. 相似文献
109.
Vinodh A. Edward Melanie Huch Carine Dortu Philippe Thonart Moutairou Egounlety Petrus J. Van Zyl Suren Singh Wilhelm H. Holzapfel Charles M.A.P. Franz 《Food Control》2011,22(3-4):389-395
Based on their predominance in Gari fermentations, as well as suitable technological properties, Lactobacillus plantarum, Lactobacillus fermentum, Weissella paramesenteroides and Leuconostoc mesenteroides strains were investigated for their suitability for development as starter strains for this African traditional fermented cassava product. The strains were grown in optimized growth media in 2 L fermenters, harvested and freeze dried, and then tested in lab-scale cassava mash fermentation trials for their ability to ferment the cassava. The strains performed well and rapidly increased the titratable acidity from 1.1 to 1.3% at 24 h to 1.3–1.6% at 48 h. The benefit of including starter cultures was that it lowered the pH of the product much faster and to lower levels than in the uninoculated control fermentation. The results furthermore indicated that especially the L. plantarum-group strains could be produced as starter strains at low cost. Overall, the results of this study showed that starter strains could be easily and economically produced, and thus represent a feasible possibility for further development for application in the field. 相似文献
110.
欧洲化学品管理局(ECHA)现已将重铬酸盐列入了高关注物质(SVHC)的名单.用含有重铬酸钾和重铬酸钠等的媒介染料染制羊毛的工厂正面临着越来越大的压力.这意味着采用这种技术的染厂未来可能要得到特别授权才能使用这种化学品. 相似文献