全文获取类型
收费全文 | 3609篇 |
免费 | 186篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 59篇 |
综合类 | 14篇 |
化学工业 | 774篇 |
金属工艺 | 67篇 |
机械仪表 | 66篇 |
建筑科学 | 193篇 |
矿业工程 | 4篇 |
能源动力 | 97篇 |
轻工业 | 336篇 |
水利工程 | 32篇 |
石油天然气 | 32篇 |
无线电 | 258篇 |
一般工业技术 | 621篇 |
冶金工业 | 505篇 |
原子能技术 | 26篇 |
自动化技术 | 712篇 |
出版年
2023年 | 55篇 |
2022年 | 80篇 |
2021年 | 116篇 |
2020年 | 61篇 |
2019年 | 64篇 |
2018年 | 78篇 |
2017年 | 82篇 |
2016年 | 127篇 |
2015年 | 120篇 |
2014年 | 125篇 |
2013年 | 207篇 |
2012年 | 173篇 |
2011年 | 231篇 |
2010年 | 216篇 |
2009年 | 168篇 |
2008年 | 166篇 |
2007年 | 150篇 |
2006年 | 151篇 |
2005年 | 127篇 |
2004年 | 103篇 |
2003年 | 82篇 |
2002年 | 84篇 |
2001年 | 76篇 |
2000年 | 55篇 |
1999年 | 74篇 |
1998年 | 147篇 |
1997年 | 86篇 |
1996年 | 67篇 |
1995年 | 57篇 |
1994年 | 35篇 |
1993年 | 37篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 23篇 |
1989年 | 29篇 |
1988年 | 21篇 |
1987年 | 19篇 |
1986年 | 18篇 |
1985年 | 31篇 |
1984年 | 14篇 |
1983年 | 23篇 |
1982年 | 22篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 16篇 |
1977年 | 9篇 |
1976年 | 34篇 |
1975年 | 10篇 |
1973年 | 7篇 |
1972年 | 7篇 |
排序方式: 共有3796条查询结果,搜索用时 78 毫秒
1.
C. Ebert presents his views on the state of software engineering as a field, its roots and inherent conflicts, its relationship to other engineering disciplines, where it is headed, and what we can do to influence that direction. T. Matsubara, T. Webb, M. Pezze, and O.W. Bertelsen offer a spectrum of further insights 相似文献
2.
Much of the writing on the psychological autopsy is reviewed. Several writers' opinions about what should be included in a comprehensive behavioral analysis conducted after an individual's death are compiled in an Appendix. Several additional and new areas to be covered in a psychological autopsy are included. The primary emphasis is on the provision of a practical guide for the working professional. Twenty-four separate factors, ranging from reconstruction of events that occurred before the death to the deceased's family death history, are presented. Some legal considerations are examined briefly in order to acquaint the professional with the significant impact that the results can have on family benefits and criminal prosecution. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
R. Boroch J. Wiaranowski R. Mueller-Fiedler M. Ebert J. Bagdahn 《Fatigue & Fracture of Engineering Materials & Structures》2007,30(1):2-12
The aim of this work is to characterize the strength properties of polycrystalline silicon (polysilicon) with the use of tensile and bending test specimens. The strength of thin polysilicon films with different geometry, size and stress concentrations has been measured and correlated with the effective size of the specimen and its stress distribution. The test results are evaluated using a probabilistic strength approach based on the weakest link theory with the use of STAU software. The use of statistic methods of strength prediction of polysilicon test structures with a complex geometry and loading based on test values for standard material tests specimen has been evaluated. 相似文献
4.
5.
6.
SecA is a dynamic protein that undergoes ATP-dependent membrane cycling to drive protein translocation across the Escherichia coli inner membrane. To understand more about this process, azide-resistant (azi) and signal sequence suppressor (prlD) alleles of secA were studied. We found that azide resistance is cold sensitive because of a direct effect on protein export, suggesting that SecA-membrane interaction is regulated by an endothermic step that is azide inhibitable. secG function is required for expression of azide-resistant and signal sequence suppressor activities of azi and prlD alleles, and in turn, these alleles suppress cold-sensitive and export-defective phenotypes of a secG null mutant. These remarkable genetic observations support biochemical data indicating that SecG promotes SecA membrane cycling and that this process is dependent on an endothermic change in SecA conformation. 相似文献
7.
Sustaining Rural Landscapes: the role of integrated tourism 总被引:2,自引:0,他引:2
The aim of a European Union-funded research project entitled 'Supporting and Promoting Integrated Tourism in Europe's Lagging Rural Regions' (SPRITE) is to analyse and develop the potential for better-integrated tourism in the rural landscapes of Europe. Integrated tourism can be defined as that which is explicitly linked to the localities in which it takes place and, in practical terms, has clear connections with local resources, activities, products, production and service industries, and a participatory local community. Enhancing the sustainable economic potential of rural landscapes requires partnerships among rural people and the sustainable yet productive use of rural resources. A 'culture economy' approach to integrated tourism is proposed, which emphasizes the importance of local identity, the strategic commodification of resources and of place, and the importance of extra-local forces in enabling local activities. It is suggested that this approach may represent a shift beyond more traditional approaches to rural development. 相似文献
8.
Pharmacological interactions are important when nuclear medical procedures are applied to patients under drug therapy, or drug provocation. This study compares in baboon models (regional) cerebral blood flow [(r)CBF] results from 99mTc-HMPAO and 123I-iodoamphetamine [123I(IMP)] each with and without acetazolamide, the latter a suggested drug for testing cerebrovascular reserve. Expected differences in cerebral uptake were observed between the two radio-tracers without acetazolamide. The increase in tracer uptake resulting from acetazolamide is significantly enhanced for 123I(IMP), which could have diagnostic implications. 相似文献
9.
Robert von Olshausen was an outstanding German gynecologist at the turn of the century and a pioneer of operative gynaecology. His fields of excellency were ovarotomy, the problems of asepsis, carcinoma therapy and the development of obstetrics in general. Under his chairmansship, the Berlin Department of Obstetrics and Gynecology (Universit?ts-Frauenklinik) became the leading Clinic in Germany. For many years Olshausen was the chairman of the Berlin Society of Obstetrics and Gynecology, since 1894 as honorary chairman. The present paper is a biography of Robert von Olshausen, showing his importance for the development of the modern gynaecology in Berlin and Germany. 相似文献
10.