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   370311篇
  免费   4288篇
  国内免费   1435篇
化学   192586篇
晶体学   5982篇
力学   17278篇
综合类   8篇
数学   41586篇
物理学   118594篇
  2020年   2747篇
  2019年   2992篇
  2018年   3686篇
  2017年   3625篇
  2016年   5880篇
  2015年   3982篇
  2014年   6044篇
  2013年   16419篇
  2012年   12651篇
  2011年   15877篇
  2010年   10668篇
  2009年   10755篇
  2008年   14580篇
  2007年   14517篇
  2006年   13890篇
  2005年   12655篇
  2004年   11633篇
  2003年   10128篇
  2002年   10038篇
  2001年   11659篇
  2000年   8908篇
  1999年   6933篇
  1998年   5627篇
  1997年   5559篇
  1996年   5344篇
  1995年   4864篇
  1994年   4683篇
  1993年   4676篇
  1992年   5019篇
  1991年   5144篇
  1990年   4681篇
  1989年   4646篇
  1988年   4688篇
  1987年   4517篇
  1986年   4279篇
  1985年   6017篇
  1984年   6162篇
  1983年   5017篇
  1982年   5357篇
  1981年   5160篇
  1980年   5003篇
  1979年   5106篇
  1978年   5215篇
  1977年   5136篇
  1976年   5199篇
  1975年   4873篇
  1974年   4841篇
  1973年   4952篇
  1972年   3282篇
  1971年   2567篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Journal of Thermal Analysis and Calorimetry - The paper focuses on the analytical analysis of the propagation of a normal shock wave in an adiabatic gas flow with nanoparticles. A modified...  相似文献   
92.
Journal of Russian Laser Research - We discuss the use of high-pressure high-temperature (HPHT) diamonds for the determination of trace amounts of various Raman active substances. The amount of the...  相似文献   
93.

A model with 16 moments is here presented in the framework of RET of polyatomic gases. It furnishes as principal subsystem the relativistic counterpart of a work by Arima T., Ruggeri T., Sugiyama M.; this is present in literature and treats the non relativistic case which incorporates relaxation processes of molecular rotation and vibration. Another principal subsystem is the natural extension of the 14 moments model by Pennisi S. and Ruggeri T.; this is also present in literature in the relativistic framework but where the trace of the third balance equation is neglected. Its extension is found here for the case when this trace isn’t neglected.

  相似文献   
94.
Exosomes are nanovesicles secreted by most cellular types that carry important biochemical compounds throughout the body with different purposes, playing a preponderant role in cellular communication. Because of their structure, physicochemical properties and stability, recent studies are focusing in their use as nanocarriers for different therapeutic compounds for the treatment of different diseases ranging from cancer to Parkinson's disease. However, current bioseparation protocols and methodologies are selected based on the final exosome application or intended use and present both advantages and disadvantages when compared among them. In this context, this review aims to present the most important technologies available for exosome isolation while discussing their advantages and disadvantages and the possibilities of being combined with other strategies. This is critical since the development of novel exosome‐based therapeutic strategies will be constrained to the effectiveness and yield of the selected downstream purification methodologies for which a thorough understanding of the available technological resources is needed.  相似文献   
95.
Physics of Atomic Nuclei - The paper presents a comparison of three neutrons identifying methods in scintillators based on ZnS with 6Li and 10B: charge integration method, pulse gradient analysis,...  相似文献   
96.
97.
Journal of Applied Spectroscopy - Aqueous solutions of human hemoglobin have been studied by the multi-angle static light scattering method. The tendency of sickle-shaped erythrocytes to aggregate...  相似文献   
98.
Crystallography Reports - Nd1 – yEuyF3 – y crystals (y is the molar fraction of EuF2; 0 ≤ y ≤ 0.15) with a tysonite (LaF3) structure have...  相似文献   
99.
Optics and Spectroscopy - The optical absorption spectra of zinc oxide (ZnO) thin films formed by reactive cathode sputtering are studied. The observed absorption of light in the region of photon...  相似文献   
100.
The biomimetic sol—gel synthesis of silicon—chitosan-containing glycerohydrogels was carried out using silicon tetraglycerolate as a precursor. It was found that chitosan accelerates gel formation in weakly acidic media. In more acidic media, the kinetics of the process changes according to the curve with a maximum, which can be attributed to different mechanisms of silanol condensation before and after the isoelectric point. The investigated silicon—chitosan-containing glycerohydrogels exhibit antibacterial, anti-inflammatory, and wound healing activity. The synthesized hybrid glycerohydrogels are promising materials for biomedical applications.  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