首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   195214篇
  免费   2379篇
  国内免费   628篇
工业技术   198221篇
  2021年   1184篇
  2019年   1289篇
  2018年   2131篇
  2017年   2110篇
  2016年   2181篇
  2015年   1494篇
  2014年   2631篇
  2013年   7987篇
  2012年   4487篇
  2011年   6129篇
  2010年   4950篇
  2009年   5798篇
  2008年   6162篇
  2007年   6207篇
  2006年   5644篇
  2005年   5290篇
  2004年   5230篇
  2003年   5047篇
  2002年   4645篇
  2001年   5041篇
  2000年   4576篇
  1999年   5201篇
  1998年   15459篇
  1997年   10145篇
  1996年   7727篇
  1995年   5749篇
  1994年   4983篇
  1993年   4988篇
  1992年   3348篇
  1991年   3231篇
  1990年   3199篇
  1989年   3000篇
  1988年   2757篇
  1987年   2209篇
  1986年   2277篇
  1985年   2597篇
  1984年   2302篇
  1983年   2048篇
  1982年   1889篇
  1981年   2027篇
  1980年   1779篇
  1979年   1646篇
  1978年   1645篇
  1977年   2019篇
  1976年   2694篇
  1975年   1418篇
  1974年   1360篇
  1973年   1305篇
  1972年   1113篇
  1971年   945篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Combustion, Explosion, and Shock Waves - This paper touches upon the effect of a polyvinyl butyral content (0–2.3%) on the combustion of a Ti + C granular...  相似文献   
3.
4.
Kirovskaya  I. A.  Filatova  T. N.  Nor  P. E. 《Semiconductors》2021,55(2):228-233
Semiconductors - According to developed methods, in the fields of the mutual solubility of initial binary compounds (InP, InSb, and CdS), solid solutions of the InP–CdS and InSb–CdS...  相似文献   
5.
Journal of Communications Technology and Electronics - Changes in the state of the surface layer of semi-insulating (111) GaAs in air under the action of white light are studied using surface...  相似文献   
6.
Theoretical Foundations of Chemical Engineering - An analytical review of the state of multiproduct chemical plants has been proposed. A comprehensive analysis is made of works of Russian and...  相似文献   
7.
One of the drawbacks of fusible clays is the narrow sintering interval due to a sharp increase in the amount of iron-silicate melt at a temperature of 1000–1100 °C, which hardens in the form of a glass phase upon cooling. This leads to a relatively low mechanical strength of the calcined samples and causes the danger of melting the granular material surface from such clays during the firing process. To increase the strength of samples of fusible clays, the influence of diabase and granitoid rocks was considered. It was found that the strengthening effect of diabase and granitoid rock additives in an amount of 20–50% in a mixture with fusible clay is due to an increase of total content of the crystalline phase (mullite, cristobalite and residual quartz) from 18–20% in clays without additives to 22–28 % - in mixtures with diabase and to 28–34% - with granitoid additives) at a temperature of 1050–1100 °C. This increase is due to the activation of synthesis processes of secondary mullite and crystallization from alkali-rich feldspar melt of amorphous silica, released from the structure of clay minerals. The established influence of the igneous rocks used made it possible to develop compositions and propose process flow sheet for producing aluminosilicate proppants based on fusible clays. The use of granitoid and diabase rocks in an amount of 20–70% with fusible clays produces lightweight aluminosilicate proppants with bulk density of 1.40–1.46 g/cm3 at temperature range of 1050–1100 °C, which can endure destructive pressures up to 34.5–52 MPa.  相似文献   
8.
Targeting protein-protein interactions (PPIs) with small-molecule inhibitors has become a hotbed of modern drug development. In this review, we describe a new class of PPI inhibitors that block menin from binding to MLL proteins. Menin is encoded by the MEN1 tumor suppressor, but acts as an essential cofactor for MLL/KMT2A-rearranged leukemias. The most promising menin-MLL inhibitors belong to the thienopyrimidine class and have recently entered phase I/II clinical trials for treating acute leukemias characterized by MLL/KMT2A translocations or NPM1 mutations. As single agents, thienopyrimidine compounds eradicate leukemia in a xenograft models of primary leukemic cells belonging to the MLL-rearranged or NPM1-mutant subtypes. These compounds are well tolerated with few or no side effects, which is remarkable given the tumor-suppressor function of menin. The menin-MLL inhibitors highlight how leukemia patients could benefit from a targeted epigenetic therapy with novel PPI inhibitors obtained by directed chemical evolution.  相似文献   
9.
Combustion, Explosion, and Shock Waves - Methyl methacrylate (MMA) is the main pyrolysis product of the widely used polymer polymethyl methacrylate; therefore, a compact mechanism of MMA...  相似文献   
10.
Analog Integrated Circuits and Signal Processing - This paper presents the complete design of a phase locked loop-based clock synthesizer for reconfigurable analog-to-digital converters. The...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号