首页 | 本学科首页   官方微博 | 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   1130篇
  免费   42篇
  国内免费   2篇
电工技术   15篇
综合类   3篇
化学工业   256篇
金属工艺   7篇
机械仪表   17篇
建筑科学   65篇
矿业工程   4篇
能源动力   92篇
轻工业   127篇
水利工程   7篇
石油天然气   3篇
无线电   51篇
一般工业技术   211篇
冶金工业   68篇
原子能技术   13篇
自动化技术   235篇
  2024年   1篇
  2023年   16篇
  2022年   16篇
  2021年   29篇
  2020年   19篇
  2019年   24篇
  2018年   25篇
  2017年   22篇
  2016年   31篇
  2015年   28篇
  2014年   50篇
  2013年   85篇
  2012年   60篇
  2011年   83篇
  2010年   74篇
  2009年   45篇
  2008年   67篇
  2007年   80篇
  2006年   64篇
  2005年   40篇
  2004年   57篇
  2003年   39篇
  2002年   30篇
  2001年   19篇
  2000年   24篇
  1999年   20篇
  1998年   17篇
  1997年   17篇
  1996年   8篇
  1995年   13篇
  1994年   8篇
  1993年   11篇
  1992年   10篇
  1991年   3篇
  1990年   6篇
  1988年   1篇
  1987年   5篇
  1986年   1篇
  1985年   9篇
  1984年   2篇
  1983年   3篇
  1982年   1篇
  1981年   2篇
  1980年   2篇
  1976年   3篇
  1975年   1篇
  1974年   2篇
  1972年   1篇
排序方式: 共有1174条查询结果,搜索用时 15 毫秒
51.
52.
Venting is the common safety measure to protect plant equipment against excessive overpressure. So far, scenarios in which particles were part of the system and should have been accounted for did ignore their presence; the scenarios were treated like a two-phase system. Current research shows that particles can have a major influence on the venting behaviour. Experimental results indicate that particles affect level swell and relief flow especially of foamy systems. Based on those results four different layers of influence of the particle have been identified and are presented in a first model. Based on this model recommendations for the development of new and more complex models are given.  相似文献   
53.
54.
55.
S100A9, a pro-inflammatory alarmin, is up-regulated in inflamed tissues. However, the role of S100A9 in regulating neutrophil activation, inflammation and lung damage in sepsis is not known. Herein, we hypothesized that blocking S100A9 function may attenuate neutrophil recruitment in septic lung injury. Male C57BL/6 mice were pretreated with the S100A9 inhibitor ABR-238901 (10 mg/kg), prior to cercal ligation and puncture (CLP). Bronchoalveolar lavage fluid (BALF) and lung tissue were harvested for analysis of neutrophil infiltration as well as edema and CXC chemokine production. Blood was collected for analysis of membrane-activated complex-1 (Mac-1) expression on neutrophils as well as CXC chemokines and IL-6 in plasma. Induction of CLP markedly increased plasma levels of S100A9. ABR-238901 decreased CLP-induced neutrophil infiltration and edema formation in the lung. In addition, inhibition of S100A9 decreased the CLP-induced up-regulation of Mac-1 on neutrophils. Administration of ABR-238901 also inhibited the CLP-induced increase of CXCL-1, CXCL-2 and IL-6 in plasma and lungs. Our results suggest that S100A9 promotes neutrophil activation and pulmonary accumulation in sepsis. Targeting S100A9 function decreased formation of CXC chemokines in circulation and lungs and attenuated sepsis-induced lung damage. These novel findings suggest that S100A9 plays an important pro-inflammatory role in sepsis and could be a useful target to protect against the excessive inflammation and lung damage associated with the disease.  相似文献   
56.
We present analytical solutions to the steady state nucleation-condensation-coagulation equation of aerosols in the atmosphere. These solutions are appropriate under different limits but more general than previously derived analytical solutions. For example, we provide an analytic solution to the coagulation limit plus a condensation correction. Our solutions are then compared with numerical results. We show that the solutions can be used to estimate the sensitivity of the cloud condensation nuclei number density to the nucleation rate of small condensation nuclei and to changes in the formation rate of sulfuric acid.

© 2016 American Association for Aerosol Research  相似文献   

57.
58.
Continuous hydrogenation reaction of ethyl benzoylformate was studied over a (–)‐cinchonidine (CD)‐modified Pt/Al2O3 catalyst. The catalyst showed a good stability, and high enantioselectivity was achieved in the fixed‐bed reactor. Chromatographic separation of (R)‐ and (S)‐ethyl mandelate originating from a post‐continuous hydrogenation reaction of ethyl benzoylformate over the (–)‐CD‐modified Pt/Al2O3 catalyst was investigated in the same reaction mixture. A commercial column filled with a chiral selector resin was chosen as a perspective preparative‐scale adsorbent. Since adsorption equilibrium isotherms were linear within the entire investigated range of concentrations, they were determined by pulse experiments for the isomers present in a post‐reaction mixture. Breakthrough curves were measured and described successfully by the dispersive plug‐flow model with linear driving force approximation.  相似文献   
59.
60.
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