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   31977篇
  免费   3985篇
  国内免费   29篇
  2017年   215篇
  2016年   299篇
  2015年   389篇
  2014年   488篇
  2013年   767篇
  2012年   770篇
  2011年   859篇
  2010年   586篇
  2009年   483篇
  2008年   703篇
  2007年   767篇
  2006年   719篇
  2005年   739篇
  2004年   750篇
  2003年   759篇
  2002年   746篇
  2001年   1989篇
  2000年   1938篇
  1999年   1523篇
  1998年   507篇
  1997年   497篇
  1996年   505篇
  1995年   443篇
  1994年   451篇
  1993年   450篇
  1992年   1144篇
  1991年   1148篇
  1990年   1137篇
  1989年   1110篇
  1988年   1020篇
  1987年   962篇
  1986年   827篇
  1985年   791篇
  1984年   635篇
  1983年   544篇
  1982年   390篇
  1981年   370篇
  1980年   364篇
  1979年   603篇
  1978年   468篇
  1977年   437篇
  1976年   368篇
  1975年   472篇
  1974年   495篇
  1973年   431篇
  1972年   406篇
  1971年   333篇
  1970年   273篇
  1969年   251篇
  1968年   240篇
排序方式: 共有10000条查询结果,搜索用时 962 毫秒
111.
112.
The location of initiation factor eIF-2 and of its subunits in quaternary initiation complexes (40S-ribosomal-subunit.eIF-2. GuoPP[CH2]P.Met-tRNAf) was investigated by immunoelectron microscopy. Quaternary complexes were fixed with glutaraldehyde and reacted with affinity-purified polyclonal antibodies against eIF-2 alpha, eIF-2 beta or eIF-2 gamma. The dimeric immune complexes obtained by sucrose gradient centrifugation were investigated electron microscopically after negative staining. Antibody-binding sites were observed on the interface side of the 40S ribosomal subunit in the region between the 'head' and the 'body' (neck region) of the 40S ribosomal subunit. Within this region, eIF-2 alpha points to the rear side, whereas eIF-2 beta and eIF-2 gamma point to the frontal side of the 40S subunit indicating an elongated shape of eIF-2 about 15 nm long. By analytical ultracentrifugation of isolated eIF-2 the sedimentation and diffusion coefficients were determined to be 6.54 S and 4.74 x 10(-7) cm2/s respectively. From these data, a molar mass of 122.4 kg/mol and a dry volume of 147.4 nm3 were calculated. For the shape of eIF-2 a prolate ellipsoid of revolution is assumed with a maximal length of about 15 nm and with an axial ratio of about 1:3.5. This conclusion is further confirmed by a calculated frictional ratio of 1.37 and a Stokes radius of about 4.54 nm.  相似文献   
113.
114.
Chromatic adaptation of the Paradise fish, Macropodus opercularis L., to illuminated backgrounds ranging from "white" to "black" shows that the pigment is most readily dispersed in the deepest-lying melanophores and least readily in the uppermost layers.  相似文献   
115.
116.
117.
118.
119.
120.
The total population affected with non-Hodgkin's lymphoma and treated by means of radiotherapy or combined radio-chemotherapy between 1960 and 1985 at the Medical Academy Dresden was analysed as to prognosis. 247 patients were classified according to the previous German scheme, 79 were subdivided on the basis of the recommendations laid down in the Kiel classification. The remission rates and survival curves achieved will stand out the comparison with international literature (remission rates of the low malignancy group amounted to 85.3 p.c. and those of the high malignancy group to 80.0 p.c.; the 5-years survival rates of the low malignancy group amounted to 61.9 p.c. and those of the high malignancy group to 41.7 p.c.). The influence of histology, clinical stage and involvement of organs is discussed on the basis of our results and informations obtained in literature. Our analysis confirms the high importance which must be attached to a common radiologic-internal outpatient-department for co-ordinating the diagnostic and therapeutical programme.  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