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   3171篇
  免费   53篇
化学   1558篇
晶体学   23篇
力学   64篇
数学   446篇
物理学   1133篇
  2018年   35篇
  2017年   43篇
  2016年   87篇
  2015年   73篇
  2014年   88篇
  2013年   208篇
  2012年   84篇
  2011年   121篇
  2010年   71篇
  2009年   59篇
  2008年   142篇
  2007年   119篇
  2006年   136篇
  2005年   59篇
  2004年   73篇
  2003年   65篇
  2002年   76篇
  2001年   54篇
  2000年   64篇
  1999年   46篇
  1998年   39篇
  1997年   32篇
  1996年   30篇
  1995年   47篇
  1994年   37篇
  1993年   37篇
  1992年   44篇
  1991年   29篇
  1990年   31篇
  1989年   39篇
  1988年   29篇
  1987年   35篇
  1986年   46篇
  1985年   56篇
  1984年   49篇
  1983年   35篇
  1982年   44篇
  1981年   38篇
  1980年   42篇
  1979年   38篇
  1978年   49篇
  1977年   37篇
  1976年   46篇
  1975年   47篇
  1974年   41篇
  1972年   32篇
  1969年   39篇
  1968年   34篇
  1967年   26篇
  1966年   36篇
排序方式: 共有3224条查询结果,搜索用时 453 毫秒
31.
Starting from the complex supersymmetry and showing that the stabilizing term is directly present in the kinetic term of the vector superfield, we show a possibility to obtain supersymmetric skyrmion.  相似文献   
32.
33.
First experimental results of160Tb nuclear orientation in yttrium single crystal matrix are described. The influence of external magnetic field in combination with the crystal field interaction is discussed.  相似文献   
34.
The results of NMR/ON measurements on56'57'60Co isotopes in iron are presented. To avoid the uncertainties caused by local demagnetizing field inhomogenities the measurements on two cobalt isotopes in one sample have been carried out. The values of nuclear-factor ratios 57/ 60 = 1.805 (20), 60/ 56 = 0.761 (20), 56/ 57 = 0.726 (20) and hyperfine anomalies5660 = -0.036 (10),60 57 = 0.017 (10) and5756 = 0.018 (10) have been calculated from the experimental results.  相似文献   
35.
This contribution presents birefringence spectra for orthorhombic YAlO3Ce single crystal in the region 2–5 eV. The spectra were measured by means of a reflection method of null ellipsometry and were compared with spectra of YAlO3:Nd determined from values measured in the region of lower energies (1·1–2·2 eV). We have found that there are differences between the spectra of YAlO3Nd and YAlO3:Ce which are most pronounced in thea-axis direction.The author is most grateful to Ing. . Viovský CSc. for helpful discussions during the course of this work and to Monokrystaly Turnov for preparation of the samples.  相似文献   
36.
The results of NMR/ON measurements on56,57,60Co isotopes in iron are presented in the paper. To avoid the uncertainties caused by local demagnetizing field inhomogeneities the measurements on two cobalt isotopes in one sample have been carried out. The values of nuclear-factors ratios 57/ 60=1·805(20), 60/ 56 = 0·761(20), 56/ 57 = 0·726(20) and hyperfme anomalies56 60 = –0·036(10),60 57 = 0·017(10) and57 56 = 0·018(10) have been calculated from the experimental results.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research.  相似文献   
37.
38.
39.
51V quadrupolar central transition NMR spectra of buffered (pH 7.6-8.0) solutions of bovine apo-transferrin (Tf) and bovine prostatic acid phosphatase (Pp) treated with vanadate show normal features (chemical shifts between -515 and -542 ppm) corresponding to the complexation of VO2+ to the Tf binding site and the Pp active centre, respectively. Addition of H2O2 leads to the temporary formation of complexed VO(O2)+ (delta approximately -595). Vanadate-dependent bromoperoxidase from the alga Ascophyllum nodosum exhibits an unusually high shielding both for the native (delta = -931) and the peroxo form (delta = -1135) of the enzyme. A resonance at -471 ppm is traced back to an inactive form with oxovanadium(V) in a trigonal-bipyramidal array.  相似文献   
40.
Bimetallic ruthenium-tin catalysts were prepared using the sol-gel method and the method of carrier impregnation. Two different procedures were used for their reduction — reduction in hydrogen atmosphere under an increased temperature, and reduction using an aqueous solution of sodium borohydride. Hydrogenation of 3-phenylpropenal (cinnamaldehyde) in tetrahydrofuran at 433 K and the total pressure 7 MPa was used as the model reaction for comparing the catalytic properties of the prepared catalysts. It was demonstrated that a tin addition notably affected catalytic properties of ruthenium in the sense of a selectivity increment related to the production of an unsaturated alcohol.  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