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   17713篇
  免费   1503篇
  国内免费   2篇
  19218篇
  2023年   76篇
  2022年   180篇
  2021年   318篇
  2020年   197篇
  2019年   222篇
  2018年   313篇
  2017年   292篇
  2016年   476篇
  2015年   769篇
  2014年   897篇
  2013年   1086篇
  2012年   1466篇
  2011年   1359篇
  2010年   819篇
  2009年   756篇
  2008年   1051篇
  2007年   1095篇
  2006年   925篇
  2005年   903篇
  2004年   810篇
  2003年   797篇
  2002年   790篇
  2001年   247篇
  2000年   186篇
  1999年   218篇
  1998年   201篇
  1997年   145篇
  1996年   132篇
  1995年   119篇
  1994年   108篇
  1993年   105篇
  1992年   139篇
  1991年   127篇
  1990年   112篇
  1989年   97篇
  1988年   94篇
  1987年   116篇
  1986年   86篇
  1985年   100篇
  1984年   84篇
  1983年   66篇
  1981年   72篇
  1980年   59篇
  1979年   81篇
  1978年   74篇
  1974年   62篇
  1972年   55篇
  1971年   55篇
  1970年   55篇
  1969年   57篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
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   
12.
13.
Nowadays, the MONOD conception is the foundation for modelling the growth-connected substrat consumption. The methods of the parameter estimation for μmax and Ks have a variable exactness. Using the experimental MONOD 's data [1] variable graphical and numerical methods are analyzed from the point of statistical view. Appropriate objective functions are proposed.  相似文献   
14.
15.
16.
17.
The 3,5,3'-triiodothyroacetic acid (TRIAC) has been approved as a valuable agent in the management of hyperthyroidism secondary to inappropriate secretion of thyrotropin. We have developed a fast protein liquid chromatography (FPLC) method for separation and quantification of TRIAC. Serum samples charged with TRIAC were extracted with methanol/ammonium acetate, the supernatants were evaporated to dryness, reconstituted in NaOH and injected on a reversed phase column for chromatography. For separation an isocratic elution method (methanol water; 0.1% trifluoroacetic acid) was used. The area under the curve (ml%) was compared with those of the calibration curves. Recoveries were 70 +/- 10.8%. TRIAC was eluted in 2.33 ml. Conclusively, the present method shows that TRIAC can be measured by FPLC and may be applied to the measurement of TRIAC in pharmacological studies.  相似文献   
18.
Maternal factors in onset of Huntington disease.   总被引:11,自引:7,他引:4       下载免费PDF全文
Analyses of father-offspring and mother-offspring similarity in onset age suggest that nuclear genes account for a significant portion of the modification of onset age in Huntington disease. The effects of non-nuclear modifiers are supported by the finding that the offspring of affected women have significantly older mean ages of onset than offspring of affected men irrespective of the onset age in the parent. The absence of increased father-daughter similarity indicates that modification is not X-linked. The absence of reproductive advantage for late-onset individuals and the absence of a multigenerational maternal-lineage effect suggest that the modifying effect of the sex of the affected parent occurs in a single parental generation. Offspring of affected women with onset between ages 35 and 49 had a significantly older mean onset age than their mothers. This suggests that a protective effect may be conferred upon the offspring of affected women.  相似文献   
19.
Adult male Saguinus mystax tamarins were evaluated for sperm parameters and testicular volumes. Sperm concentrations average 195.5 X 10(6)/cc with 41.7% motile sperm. Semen specimens were classified as normal, relative to sperm morphology, when 95% or more of the sperm in the specimen had normal morphology; 76% of the animals evaluated had normal semen specimens using this criterion. Testicular volumes averaged 726.9 mm3. A total of 50 infants were sired by 16 of these males during the period covered by this report.  相似文献   
20.
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