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   11142篇
  免费   353篇
  国内免费   28篇
化学   7197篇
晶体学   70篇
力学   383篇
综合类   5篇
数学   1451篇
物理学   2417篇
  2023年   88篇
  2022年   311篇
  2021年   345篇
  2020年   259篇
  2019年   291篇
  2018年   266篇
  2017年   203篇
  2016年   408篇
  2015年   321篇
  2014年   404篇
  2013年   667篇
  2012年   747篇
  2011年   815篇
  2010年   555篇
  2009年   583篇
  2008年   716篇
  2007年   627篇
  2006年   573篇
  2005年   477篇
  2004年   409篇
  2003年   309篇
  2002年   277篇
  2001年   178篇
  2000年   161篇
  1999年   111篇
  1998年   104篇
  1997年   102篇
  1996年   95篇
  1995年   75篇
  1994年   91篇
  1993年   86篇
  1992年   82篇
  1991年   56篇
  1990年   49篇
  1989年   40篇
  1988年   35篇
  1987年   34篇
  1986年   37篇
  1985年   46篇
  1984年   51篇
  1983年   40篇
  1982年   41篇
  1981年   48篇
  1980年   38篇
  1979年   36篇
  1978年   32篇
  1977年   27篇
  1976年   24篇
  1975年   27篇
  1973年   23篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
1.
2.
3.
Journal of Thermal Analysis and Calorimetry - The aim of this work is to synthesize and characterize a new structured silver–clay dried, calcined or sintered at different temperatures...  相似文献   
4.
5.
6.
Central European Journal of Operations Research - Societal awareness and legislation changes concerning sustainability have affected how organizations generate value for stakeholders, as well as...  相似文献   
7.
Meccanica - Fiber reinforced materials are used in assorted engineering application and for this reason, new additive manufacturing technologies have been developed for this type of materials. With...  相似文献   
8.
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   
9.
Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an...  相似文献   
10.
An innovative volatolomic approach employs the detection of biomarkers present in cerumen (earwax) to identify cattle intoxication by Stryphnodendron rotundifolium Mart., Fabaceae (popularly known as barbatimão). S. rotundifolium is a poisonous plant with the toxic compound undefined and widely distributed throughout the Brazilian territory. Cerumen samples from cattle of two local Brazilian breeds (‘Curraleiro Pé-Duro’ and ‘Pantaneiro’) were collected during an experimental intoxication protocol and analyzed using headspace (HS)/GC–MS followed by multivariate analysis (genetic algorithm for a partial least squares, cluster analysis, and classification and regression trees). A total of 106 volatile organic metabolites were identified in the cerumen samples of bovines. The intoxication by S. rotundifolium influenced the cerumen volatolomic profile of the bovines throughout the intoxication protocol. In this way, it was possible to detect biomarkers for cattle intoxication. Among the biomarkers, 2-octyldecanol and 9-tetradecen-1-ol were able to discriminate all samples between intoxicated and nonintoxicated bovines. The cattle intoxication diagnosis by S. rotundifolium was accomplished by applying the cerumen analysis using HS/GC–MS, in an easy, accurate, and noninvasive way. Thus, the proposed bioanalytical chromatography protocol is a useful tool in veterinary applications to determine this kind of intoxication.  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