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   195426篇
  免费   2380篇
  国内免费   628篇
工业技术   198434篇
  2021年   1203篇
  2019年   1288篇
  2018年   2130篇
  2017年   2120篇
  2016年   2180篇
  2015年   1493篇
  2014年   2629篇
  2013年   7968篇
  2012年   4472篇
  2011年   6122篇
  2010年   4941篇
  2009年   5790篇
  2008年   6168篇
  2007年   6209篇
  2006年   5655篇
  2005年   5324篇
  2004年   5263篇
  2003年   5108篇
  2002年   4652篇
  2001年   5056篇
  2000年   4581篇
  1999年   5200篇
  1998年   15465篇
  1997年   10153篇
  1996年   7725篇
  1995年   5761篇
  1994年   4987篇
  1993年   4996篇
  1992年   3349篇
  1991年   3234篇
  1990年   3200篇
  1989年   3001篇
  1988年   2758篇
  1987年   2206篇
  1986年   2273篇
  1985年   2596篇
  1984年   2306篇
  1983年   2055篇
  1982年   1892篇
  1981年   2026篇
  1980年   1780篇
  1979年   1645篇
  1978年   1648篇
  1977年   2025篇
  1976年   2700篇
  1975年   1421篇
  1974年   1362篇
  1973年   1308篇
  1972年   1115篇
  1971年   943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