全文获取类型
收费全文 | 56592篇 |
免费 | 17047篇 |
国内免费 | 1353篇 |
专业分类
化学 | 62608篇 |
晶体学 | 191篇 |
力学 | 2523篇 |
综合类 | 128篇 |
数学 | 3990篇 |
物理学 | 5552篇 |
出版年
2024年 | 392篇 |
2023年 | 4207篇 |
2022年 | 1815篇 |
2021年 | 2859篇 |
2020年 | 4994篇 |
2019年 | 2731篇 |
2018年 | 2606篇 |
2017年 | 963篇 |
2016年 | 6023篇 |
2015年 | 5960篇 |
2014年 | 5514篇 |
2013年 | 5823篇 |
2012年 | 4128篇 |
2011年 | 1954篇 |
2010年 | 4009篇 |
2009年 | 3943篇 |
2008年 | 1750篇 |
2007年 | 1431篇 |
2006年 | 671篇 |
2005年 | 595篇 |
2004年 | 410篇 |
2003年 | 355篇 |
2002年 | 335篇 |
2001年 | 294篇 |
2000年 | 268篇 |
1999年 | 246篇 |
1998年 | 224篇 |
1997年 | 246篇 |
1996年 | 266篇 |
1995年 | 320篇 |
1994年 | 218篇 |
1993年 | 341篇 |
1992年 | 215篇 |
1988年 | 172篇 |
1985年 | 162篇 |
1982年 | 157篇 |
1981年 | 172篇 |
1980年 | 215篇 |
1979年 | 209篇 |
1978年 | 204篇 |
1977年 | 326篇 |
1976年 | 384篇 |
1975年 | 469篇 |
1974年 | 488篇 |
1973年 | 310篇 |
1972年 | 384篇 |
1971年 | 361篇 |
1970年 | 545篇 |
1969年 | 420篇 |
1968年 | 461篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
In this paper we investigate the
probabilistic linear $(n,\delta)$-widths and $p$-average linear
$n$-widths of the Sobolev space $W^r_2$ equipped with the Gaussian
measure $\mu$ in the $L_{\infty}$-norm, and determine the
asymptotic equalities
\begin{eqnarray*}
\lambda_{n,\delta}(W^r_2,\mu,L_{\infty})
&\asymp&\frac{\sqrt{\ln
(n/\delta)}}{n^{r+(s-1)/2}},\\[3pt]
\lambda^{(a)}_n(W^r_2,\mu,L_{\infty})_p &\asymp&\frac{\sqrt{\ln
n}}{n^{r+(s-1)/2}}, \qquad 0 < p < \infty.
\end{eqnarray*} 相似文献
42.
现代教育技术在物理教学中的应用 总被引:1,自引:0,他引:1
现代教育技术与课程教学的整合,是我国面向21世纪基础教育教学改革的新视点。笔者就物理教学中应用现代教育技术的实践作初步探讨。 相似文献
43.
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
44.
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
45.
Michael C. W. Chan Dr. 《化学:亚洲杂志》2008,3(1):18-27
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
46.
47.
Dr. Guido Goldschmiedt 《Monatshefte für Chemie / Chemical Monthly》1885,6(1):372-403
Ohne Zusammenfassung 相似文献
48.
《基础教育课程改革纲要》要求 :要“大力推进信息技术在教学过程中的普遍应用 ,促进信息技术与学科课程的整合 ,逐步实现教学内容的呈现方式、学生的学习方式、教师的教学方式和师生互动方式的变革 ,充分发挥信息的优势 ,为学生的学习和发展提供丰富多彩的教育环境和有力的学习工具 .”可见 :信息技术与其它课程的整合是课程教学中把信息技术、信息资源、信息方法和课程内容有机结合 ,是一种新型的教学方式 .下面讨论几个具体层面上的问题 :1 信息技术与物理教学目标和内容的整合面对新世纪 ,信息处理的技能、学习能力、问题解决能力、与… 相似文献
49.
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
50.