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   78655篇
  免费   17454篇
  国内免费   327篇
化学   71277篇
晶体学   308篇
力学   3666篇
综合类   12篇
数学   12020篇
物理学   9153篇
  2024年   459篇
  2023年   4756篇
  2022年   1614篇
  2021年   2806篇
  2020年   5154篇
  2019年   2558篇
  2018年   3721篇
  2017年   2093篇
  2016年   6798篇
  2015年   6630篇
  2014年   5942篇
  2013年   6296篇
  2012年   6528篇
  2011年   3366篇
  2010年   5499篇
  2009年   5198篇
  2008年   1638篇
  2007年   1358篇
  2006年   674篇
  2005年   4474篇
  2004年   3935篇
  2003年   2323篇
  2002年   496篇
  2001年   323篇
  1999年   194篇
  1997年   157篇
  1995年   221篇
  1994年   154篇
  1993年   269篇
  1992年   292篇
  1991年   246篇
  1990年   199篇
  1989年   189篇
  1988年   235篇
  1987年   169篇
  1982年   159篇
  1981年   185篇
  1980年   216篇
  1979年   235篇
  1978年   243篇
  1977年   352篇
  1976年   473篇
  1975年   515篇
  1974年   541篇
  1973年   371篇
  1972年   494篇
  1971年   441篇
  1970年   659篇
  1969年   496篇
  1968年   537篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
The field of medicinal inorganic chemistry is rapidly advancing. In particular organometallic complexes have much potential as therapeutic and diagnostic agents. The carbon‐bound and other ligands allow the thermodynamic and kinetic reactivity of the metal ion to be controlled and also provide a scaffold for functionalization. The establishment of structure–activity relationships and elucidation of the speciation of complexes under conditions relevant to drug testing and formulation are crucial for the further development of promising medicinal applications of organometallic complexes. Specific examples involving the design of ruthenium and osmium arene complexes as anticancer agents are discussed.  相似文献   
92.
In this study, a genetically encoded bioluminescent indicator for ERK2 dimer was developed with the split Renilla luciferase complementation method, in which the formation of ERK2 dimer induces a spontaneous emission of bioluminescence in living cells. In response to extracellular stimuli, such as epidermal growth factor (EGF) or 17β‐estradiol (E2), extracellular signal‐regulated kinase 2 (ERK2) is phosphorylated by its upstream kinase MEK, and also phosphorylates its substrates in various regions of the cell, including the nucleus. Phosphorylated ERK2 is led to form its dimer, thereby transporting itself into the nucleus. We demonstrated with the indicator that stimulation with EGF or E2 induces the formation of ERK2 dimer in living MCF‐7 cells. The dynamics of this dimer formation was examined and discussed.  相似文献   
93.
The notion of weak attractive ligand–polymer interactions is introduced, and its potential application, importance, and conceptual links with “cooperative” ligand–substrate interactions are discussed. Synthetic models of weak attractive ligand–polymer interactions are described, in which intramolecular weak C? H???F? C interactions (the existence of which remains contentious) have been detected by NMR spectroscopy and neutron and X‐ray diffraction experiments. These C? H???F? C interactions carry important implications for the design of catalysts for olefin polymerization, because they provide support for the practical feasibility of ortho‐F???Hβ ligand–polymer contacts proposed for living Group 4 fluorinated phenoxyimine catalysts. The notion of weak attractive noncovalent interactions between an “active” ligand and the growing polymer chain is a novel concept in polyolefin catalysis.  相似文献   
94.
95.
96.
97.
We prove an existence theorem for a nonlinear integral equation being a Volterra counterpart of an integral equation arising in the traffic theory. The method used in the proof allows us to obtain additional characterization in terms of asymptotic stability of solutions of an equation in question.  相似文献   
98.
Gallin Peter Prof. Dr. 《ZDM》2003,35(3):110-119
In order to emphasize functional thinking in mathematical education, arguments are brought forward for an early and frequent use of tree diagrams in teaching stochastics. Since set and tree diagrams can be regarded as two sides of the same matter, Bayes’ theorem, which is strongly associated with predicative set diagrams, need not be dealt with explicitly any longer. Set diagrams are replaced by tree diagrams that are labelled in detail and by tree inversion as a functional instrument of dealing with conditioned probabilities. This technique is demonstrated by three typical problems in the context of conditioned probability. Finally, two letters by Pascal to Fermat are analysed in order to illustrate that predicative and functional approaches were already pursued in the early stages of probability calculus in the 17th century.  相似文献   
99.
100.
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