全文获取类型
收费全文 | 1454909篇 |
免费 | 24179篇 |
国内免费 | 6959篇 |
专业分类
电工技术 | 34061篇 |
综合类 | 6335篇 |
化学工业 | 268179篇 |
金属工艺 | 63498篇 |
机械仪表 | 40596篇 |
建筑科学 | 44941篇 |
矿业工程 | 11311篇 |
能源动力 | 50111篇 |
轻工业 | 105569篇 |
水利工程 | 14489篇 |
石油天然气 | 37380篇 |
武器工业 | 128篇 |
无线电 | 194465篇 |
一般工业技术 | 274489篇 |
冶金工业 | 140316篇 |
原子能技术 | 33843篇 |
自动化技术 | 166336篇 |
出版年
2021年 | 15452篇 |
2020年 | 11736篇 |
2019年 | 14492篇 |
2018年 | 14505篇 |
2017年 | 13729篇 |
2016年 | 20622篇 |
2015年 | 17149篇 |
2014年 | 28505篇 |
2013年 | 87466篇 |
2012年 | 33799篇 |
2011年 | 45274篇 |
2010年 | 41130篇 |
2009年 | 49939篇 |
2008年 | 42651篇 |
2007年 | 39586篇 |
2006年 | 43333篇 |
2005年 | 37856篇 |
2004年 | 40295篇 |
2003年 | 40236篇 |
2002年 | 39541篇 |
2001年 | 35989篇 |
2000年 | 34714篇 |
1999年 | 33361篇 |
1998年 | 37548篇 |
1997年 | 34753篇 |
1996年 | 32466篇 |
1995年 | 29033篇 |
1994年 | 27433篇 |
1993年 | 27316篇 |
1992年 | 25658篇 |
1991年 | 22693篇 |
1990年 | 23098篇 |
1989年 | 22164篇 |
1988年 | 20644篇 |
1987年 | 19030篇 |
1986年 | 18292篇 |
1985年 | 21664篇 |
1984年 | 22052篇 |
1983年 | 20025篇 |
1982年 | 19066篇 |
1981年 | 19177篇 |
1980年 | 17781篇 |
1979年 | 18363篇 |
1978年 | 17609篇 |
1977年 | 17098篇 |
1976年 | 17510篇 |
1975年 | 15903篇 |
1974年 | 15426篇 |
1973年 | 15517篇 |
1972年 | 12994篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The use of patent titles for identifying the topics of invention and forecasting trends 总被引:7,自引:0,他引:7
Co-word analysis applied to patents through WPIL normalized title words appears to give a useful picture of a given field: we obtain both qualitative (themes) and quantitative information (weight of themes). It also gives information about the strategic aspects of the themes. Furthermore, in some cases, it is an indication of the future of certain themes that may help forecasting and management studies. Finally, it provides information about what could be a real technology growth process, in relation to the so-called translation model used in co-word analysis. 相似文献
992.
993.
F. Cioffi E. M. Cohen Richard Badick 《Drug development and industrial pharmacy》1993,19(14):1741-1746
Carstensen and Rhodes1 have suggested that when, in stability programs, assays cannot be performed immediately after the protocol-designated storage time, then freezing them until such a time when assays can be performed would be a reasonable manner to retain the protocol schedule. They caution, however, that such a procedure may not be valid for dissolution data. The article to follow deals with real-time data showing that such a process is feasible for Nalidixic Acid tablets (and presumably for other tablets as well), and that, furthermore, the dissolution pattern would seem to be “frozen” as well. 相似文献
994.
Translated from Izmeritel'naya Tekhnika, No. 3, pp. 40–42, March, 1993. 相似文献
995.
996.
997.
A. G. Strunina 《Journal of Engineering Physics and Thermophysics》1993,65(4):953-956
The process of combustion of homogeneous and heterogeneous nongasifying and slightly gasifying systems over the range of a number of parameters characterizing the reactive composition and the conditions for the arrangement of the combustion process is studied by using thermocouple and optical methods. The regions of the implementation of different combustion regimes, namely, steady, pulsating, multiple-point, and spin, are determined experimentally.Institute of Structural Macrokinetics, Russian Academy of Sciences, Chernogolovka. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 4, pp. 407–411, October, 1993. 相似文献
998.
Sh. V. Gedevanishvili V. I. Yukhvid G. Sh. Oniashvili 《Journal of Engineering Physics and Thermophysics》1993,65(5):1134-1137
Use of inexpensive ore concentrates as initial components in SHS metallurgy [1–3] brings about some specific features in the process and the properties of the materials obtained. Ore reagents contain a considerable amount of impurities (Al2O3, SiO2, Fe2O3) that decrease the energetics of SHS systems and the temperature and the rate of combustion and create the limits of combustion and phase separation. In addition, the impurities participate in chemical reactions and enter the desired product. In many cases the presence of silicon, iron, and aluminum in a cast product does not prevent use of this product for practical purposes.Institute of Metallurgy, Academy of Sciences of the Republic of Georgia, Tbilisi. Institute of Structural Macrokinetics, Russian Academy of Sciences, Chernogolovka. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 5, pp. 613–616, November, 1993. 相似文献
999.
1000.