全文获取类型
收费全文 | 63778篇 |
免费 | 6821篇 |
国内免费 | 6415篇 |
专业分类
化学 | 40515篇 |
晶体学 | 544篇 |
力学 | 4496篇 |
综合类 | 379篇 |
数学 | 8647篇 |
物理学 | 22433篇 |
出版年
2023年 | 772篇 |
2022年 | 1487篇 |
2021年 | 1604篇 |
2020年 | 1693篇 |
2019年 | 1735篇 |
2018年 | 1679篇 |
2017年 | 1564篇 |
2016年 | 2327篇 |
2015年 | 2121篇 |
2014年 | 2542篇 |
2013年 | 3442篇 |
2012年 | 3916篇 |
2011年 | 5107篇 |
2010年 | 3521篇 |
2009年 | 3419篇 |
2008年 | 3065篇 |
2007年 | 2731篇 |
2006年 | 2497篇 |
2005年 | 2402篇 |
2004年 | 2877篇 |
2003年 | 2200篇 |
2002年 | 2195篇 |
2001年 | 1852篇 |
2000年 | 1299篇 |
1999年 | 1299篇 |
1998年 | 1178篇 |
1997年 | 1036篇 |
1996年 | 926篇 |
1995年 | 895篇 |
1994年 | 747篇 |
1993年 | 1049篇 |
1992年 | 1034篇 |
1991年 | 840篇 |
1990年 | 836篇 |
1989年 | 767篇 |
1988年 | 434篇 |
1987年 | 382篇 |
1986年 | 358篇 |
1985年 | 395篇 |
1984年 | 377篇 |
1983年 | 329篇 |
1982年 | 339篇 |
1978年 | 335篇 |
1977年 | 324篇 |
1976年 | 409篇 |
1975年 | 362篇 |
1974年 | 393篇 |
1973年 | 399篇 |
1972年 | 370篇 |
1971年 | 334篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
L.-Q. Han S.-Y. Zhao Y.-D. Zhou P.-L. Zhang 《Applied physics. B, Lasers and optics》1997,65(3):399-402
Received: 18 June 1996/Revised version: 3 January 1997 相似文献
63.
SINGULARBOUNDARYPROPERTIESOFHARMONICFUNCTIONSANDFRACTALANALYSISWENZHIYINGZHANGYIPINGManuscriptreceivedJanuary11,1995.Revi... 相似文献
64.
65.
V. O. Kur'yanov T. F. Zhelobetskaya A. E. Zemlyakov V. Ya. Chirva 《Chemistry of Natural Compounds》1993,29(1):103-106
The synthesis has been effected of derivatives of MDP having a spacer with an amino or carboxy group. The final stage of the synthesis was the condensation of Boc-L-Ala-D-iGln with 6-aminohexanol (followed by the two-stage replacement of the hydroxy by an azido group) or with benzyl 6-aminohexanoate.Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 122–125, January–February, 1993. 相似文献
66.
67.
68.
S. Ya. Yakubov 《Results in Mathematics》1995,28(1-2):153-168
In this paper we find conditions guarantee that irregular boundary value problems for elliptic differential-operator equations of the second order in an interval are fredholm. We apply this result to find some algebraic conditions guarantee that irregular boundary value problems for elliptic partial differential equations of the second order in cylindrical domains are fredholm. Apparently this is the first paper where the regularity of an elliptic boundary value problem is not satisfied on a manifold of the dimension equal to dimension of the boundary. Nevertheless the problem is fredholm and the resolvent is compact. It is interesting to note that the considered boundary value problems for elliptic equations in a cylinder being with separating variables are noncoercive. 相似文献
69.
We study a generalization of the notion of the chromatic number of a graph in which the colors assigned to adjacent vertices are required to be, in a certain sense, far apart. © 1993 John Wiley & Sons, Inc. 相似文献
70.
E. Ya. Paryev 《Physics of Atomic Nuclei》2006,69(2):332-354
Within the spectral function approach, we study the direct production and decay via the dikaon (dimuon) channel of ϕ mesons
in the interactions of 2.4-and 2.7-GeV protons with light and medium target nuclei. It is shown that the K
+
K
− (μ+ μ−) invariant-mass distribution consists of the two components, which correspond to the ϕ decay “outside” and “inside” the target nucleus. The first (narrow) component has the free ϕ width, while the second (broad) component is distorted by the nuclear matter owing to resonance-nucleon scattering and a
possible in-medium modification of the kaons and ρ meson at finite baryon density. The relative strength of the “inside” and “outside” components is analyzed in different scenarios
for the ϕ width and momentum cut. It is demonstrated that the width of the resulting dimuon invariant-mass distribution on medium nuclei
is larger than the free ϕ width by a factor of about 2 if the total ϕ in-medium width is used and the respective cutoff for the ϕ three-momentum is applied, whereas the resulting dikaon invariant-mass distribution has an insignificant sensitivity to the
ϕ in-medium properties owing to the strong absorption of the K
− in the surrounding nuclear matter. On the other hand, because of the distortion of the K
+ and K
− on their way out of the target nucleus mainly due to the hadronic kaon potentials, the latter distribution is broadened and
shifted to higher invariant masses, which means that the measurement of such broadening would give additional evidence for
the modification of the kaon and antikaon properties in the nuclear medium.
The text was submitted by the author in English. 相似文献