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   9149篇
  免费   307篇
  国内免费   3篇
化学   4944篇
晶体学   65篇
力学   199篇
数学   1885篇
物理学   2366篇
  2021年   101篇
  2020年   142篇
  2019年   123篇
  2018年   166篇
  2017年   156篇
  2016年   358篇
  2015年   310篇
  2014年   363篇
  2013年   622篇
  2012年   477篇
  2011年   560篇
  2010年   343篇
  2009年   277篇
  2008年   321篇
  2007年   300篇
  2006年   217篇
  2005年   134篇
  2004年   158篇
  2003年   159篇
  2002年   172篇
  2001年   126篇
  2000年   136篇
  1999年   126篇
  1998年   120篇
  1997年   108篇
  1996年   94篇
  1995年   92篇
  1994年   94篇
  1993年   85篇
  1992年   88篇
  1991年   75篇
  1990年   92篇
  1989年   77篇
  1988年   79篇
  1987年   79篇
  1986年   69篇
  1985年   107篇
  1984年   122篇
  1983年   74篇
  1982年   99篇
  1981年   96篇
  1980年   89篇
  1979年   98篇
  1978年   98篇
  1977年   87篇
  1976年   112篇
  1975年   100篇
  1974年   94篇
  1973年   80篇
  1968年   75篇
排序方式: 共有9459条查询结果,搜索用时 484 毫秒
101.
The paper deals with the problem of the outpatient administration of186Re-HEDP and153Sm-EDTMP for palliative therapy of bone metastases. The subsequent 6 hours stay of the treated patients in a department of nuclear medicine appears to be in compliance with regulations proposed in the Czech Republic as well as with ICRP recommendations.  相似文献   
102.
The phase diagrams of the binary system KF-AlF3 as well as the ternary system NaF-KF-AlF3 in the range up to 50 mol% AlF3, were measured using the thermal analysis method. In the system KF-AlF3 the coordinates of the eutectic points are: E 1: 8.0 mol% AlF3, 821.2°C, and E 2: 45.5 mol% AlF3, 565.0°C. In the investigated concentration range of the ternary system 2 eutectic points have been found with the calculated coordinates: E 1: 36.3 mol% NaF, 62.7 mol% KF, 1.0 mol% AlF3; t=711.2°C; and E 2: 51.9 mol% NaF, 27.4 mol% KF, 20.7 mol% AlF3; t=734.5°C. Other eutectic points lie most probably beyond the investigated part of the system. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
103.
Steric and electronic influences of various substituted pyridines support the hypothesis of the coordination of pyridine in the manganese porphyrin-catalysed epoxidation of olefins with sodium hypochlorite solution.  相似文献   
104.
JPC – Journal of Planar Chromatography – Modern TLC - A ternary mobile phase for thin-layer chromatographic separation and identification of seven amino acids on microcrystalline...  相似文献   
105.
Amorphous precursors for PbZrO3 and PbTiO3 ceramics were prepared from lead acetate and the transition metaln-propoxide inn-propanol orn-butoxide inn-butanol and hydrolysed with an excess of water. According to GLC and TGA/EGA analyses, the type of alkoxide group influences distinctly the structure of heterometallic precursors, i.e., oxo or acetate bridging, and the amounts of hydroxyl and organic groups bound to the metal network. The local environments of metal atoms in the amorphous precursors were also studied by EXAFS. The analysis reveals that in Pb−Zr precursors alkoxide groups modify the coordination spheres of the zirconium atoms. Conversely, local environments of both lead and titanium atoms within the analysed range of 3.4 A depend weakly on the type of alkoxide used.  相似文献   
106.
A simple analytical model is developed and solved to describe time evolution of the loop voltage and toroidal current when RF and inductive current drive take place simultaneously. A relation for the real value of the RF driven current has been obtained under these conditions. Comparison with experimental data from T-7 tokamak allows to estimate the role of the skin effect during RF current drive.The authors would like to thank A. Ya. Kislov for the basic data on the T-7 tokamak transformer. They are also indebted to V. V. Parail and G.V. Pereverzev for many clarifying discussions.  相似文献   
107.
It is shown that the Gleason theorem holds not only for a finite but also for ann-finite signed measurem, wheren is a cardinal, defined on all closed subspaces of a Hilbert space whose dimension is a nonmeasurable cardinal 2, ifm is bounded from below on all one-dimensional subspaces.  相似文献   
108.
The paper describes the results of investigations of the solar wind ions, carried out on board the high apogee Prognoz 7 and Prognoz 8 Earth's satellites with the aid of an SKS instrument (USSR) and a Monitor instrument (USSR-SSR). Behaviour of proton and that of components on the front of Earth's bow and interplanetary shock waves were compared by means of the energoanalysis and energy-mass analysis techniques. In several long-term periods of observation the solar wind heavy ions — oxygen, silicon and iron were determined. It enabled us to estimate the solar corona chemical composition and electron temperature.Presented at the 5th General Assembly IAGA/IAMAP August 5–17, 1985, Prague, Czechoslovakia.  相似文献   
109.
The dependence of the flow stress and the slip band density on the plastic strain has been measured at 201 K, 293 K and 363 K. The growth of deformation concentrated in an average slip band has been stated. The types of obstacles acting against the rise and development of a slip band and the temperature dependence of the strain hardening in AgCl crystals are discussed. An equation stating the dependence of the flow stress on the slip band density is presented. The hardening in AgCl crystals is classified as the stage III — hardening.  相似文献   
110.
The possibility of the Hahn-Jordan decomposition forn-finite signed measures, wheren is a cardinal, defined on a quantum logic of all closed subspaces of a Hilbert space whose dimension is a nonmeasurable cardinal 2, is investigated.  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