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   552290篇
  免费   12566篇
  国内免费   6168篇
化学   286095篇
晶体学   7916篇
力学   27365篇
综合类   295篇
数学   87025篇
物理学   162328篇
  2021年   4023篇
  2020年   4617篇
  2019年   4713篇
  2018年   14458篇
  2017年   14257篇
  2016年   13829篇
  2015年   7292篇
  2014年   9367篇
  2013年   23037篇
  2012年   21542篇
  2011年   31137篇
  2010年   19440篇
  2009年   19691篇
  2008年   25445篇
  2007年   27227篇
  2006年   18873篇
  2005年   17846篇
  2004年   16414篇
  2003年   15147篇
  2002年   13945篇
  2001年   14595篇
  2000年   11524篇
  1999年   9135篇
  1998年   7595篇
  1997年   7258篇
  1996年   7288篇
  1995年   6656篇
  1994年   6291篇
  1993年   6000篇
  1992年   6632篇
  1991年   6347篇
  1990年   6038篇
  1989年   5785篇
  1988年   5984篇
  1987年   5664篇
  1986年   5417篇
  1985年   7557篇
  1984年   7647篇
  1983年   6371篇
  1982年   6774篇
  1981年   6618篇
  1980年   6386篇
  1979年   6594篇
  1978年   6671篇
  1977年   6551篇
  1976年   6505篇
  1975年   6357篇
  1974年   6197篇
  1973年   6519篇
  1972年   3984篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Journal of Fluorescence - This report describes a combined immunofluorescence and fluorescence viability stain applied as one staining solution for rapid detection of live Legionella...  相似文献   
2.
Yang  T. L.  Kao  C. L.  Kuo  C. E.  Yeh  H. C.  Li  W. J.  Li  H. T.  Chen  C. Y. 《Chemistry of Natural Compounds》2022,58(5):825-827
Chemistry of Natural Compounds - A novel bibenzyl derivative, hydrangchinenin (1), was isolated from the stems of Hydrangea chinensis Maxim. (Hydrangeaceae). Its structure was determined on the...  相似文献   
3.
Research on Chemical Intermediates - Owing to the simultaneous utilization of photogenerated electrons and holes, coupling light-driven hydrogen (H2) evolution reaction (HER) and biomass-derived...  相似文献   
4.
Refractory wounds have always been an important issue to healthcare systems, whose healing process is always delayed by multiple factors, including bacterial infections, chronic inflammation, and excessive exudates, etc. Employing multifunctional wound dressings is recognized as an effective strategy to deal with refractory wounds, which has yielded promising outcomes in recent years. Among these advanced wound dressings, fibrous dressings have gained growing attention due to their unique merits. Such wound dressings have demonstrated great potential in delivering theranostic agents, such as antibacterial agents, anti-inflammatory drugs, growth factors, and diagnostic probes, etc., for the purposes of accelerating wound healing. This paper reviews the development of multifunctional fibrous dressings and their applications in treating refractory wounds. The construction approaches of novel fibrous dressing with capabilities of antibacterial, anti-inflammation, exudate management and diagnosis were also introduced. Furthermore, the existing problems and challenges are also discussed briefly.  相似文献   
5.
Kinetics and Catalysis - The results of studies in the field of synthesis and characterization of layered double hydroxides (LDHs) obtained using solid-phase reactions are summarized. The effect of...  相似文献   
6.
Journal of Structural Chemistry - A new polymorph of the [ReCl3(MeCN)(PPh3)2] complex is synthesized and characterized by single crystal X-ray diffraction (XRD). Its recrystallization from the...  相似文献   
7.
Xu  Feixiang  Luo  Jiangchen  Jiang  Liqun  Zhao  Zengli 《Cellulose (London, England)》2022,29(3):1463-1472
Cellulose - In this research, the production of levoglucosan (LG) and levoglucosenone (LGO) was improved from acid-impregnated cellulose via fast pyrolysis. Thermogravimetric and kinetic analysis...  相似文献   
8.
Russian Journal of Applied Chemistry - A method for the disposal of hydrolysis lignin waste based on its modification with ZnCl2 and FeCl3 and subsequent carbonization at 800°C was proposed....  相似文献   
9.
Journal of Applied Spectroscopy - Three simple, sensitive, precise, and rapid spectrophotometric methods are developed and optimized for the assay of vardenafil in pharmaceutical formulations. The...  相似文献   
10.

A kinetic study of the effect of thermoheliox (inhalation of a helium and oxygen mixture, 70 °C) on the functional hemodynamics of the human brain by functional magnetic resonance imaging was carried out. The dynamic responses of the BOLD signal were found to be biphasic. An empirical equation describing the first phase of the hemodynamic response to visual stimulus was proposed. It was shown that preliminary inhalation of thermoheliox stimulates the hemodynamic responses by slowing down the vasoconstriction.

  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