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   15783篇
  免费   46篇
  国内免费   101篇
系统科学   62篇
丛书文集   163篇
教育与普及   87篇
理论与方法论   48篇
现状及发展   6941篇
研究方法   719篇
综合类   7744篇
自然研究   166篇
  2013年   111篇
  2012年   237篇
  2011年   404篇
  2010年   122篇
  2009年   150篇
  2008年   267篇
  2007年   322篇
  2006年   269篇
  2005年   321篇
  2004年   321篇
  2003年   283篇
  2002年   274篇
  2001年   543篇
  2000年   522篇
  1999年   377篇
  1992年   315篇
  1991年   258篇
  1990年   283篇
  1989年   248篇
  1988年   268篇
  1987年   272篇
  1986年   211篇
  1985年   338篇
  1984年   245篇
  1983年   207篇
  1982年   223篇
  1981年   189篇
  1980年   240篇
  1979年   522篇
  1978年   417篇
  1977年   389篇
  1976年   320篇
  1975年   356篇
  1974年   402篇
  1973年   402篇
  1972年   420篇
  1971年   445篇
  1970年   520篇
  1969年   448篇
  1968年   471篇
  1967年   432篇
  1966年   399篇
  1965年   254篇
  1959年   131篇
  1958年   244篇
  1957年   169篇
  1956年   151篇
  1955年   123篇
  1954年   97篇
  1948年   90篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
942.
Radiation hybrid map of the mouse genome.   总被引:13,自引:0,他引:13  
Radiation hybrid (RH) maps are a useful tool for genome analysis, providing a direct method for localizing genes and anchoring physical maps and genomic sequence along chromosomes. The construction of a comprehensive RH map for the human genome has resulted in gene maps reflecting the location of more than 30,000 human genes. Here we report the first comprehensive RH map of the mouse genome. The map contains 2,486 loci screened against an RH panel of 93 cell lines. Most loci (93%) are simple sequence length polymorphisms (SSLPs) taken from the mouse genetic map, thereby providing direct integration between these two key maps. We performed RH mapping by a new and efficient approach in which we replaced traditional gel- or hybridization-based assays by a homogeneous 5'-nuclease assays involving a single common probe for all genetic markers. The map provides essentially complete connectivity and coverage across the genome, and good resolution for ordering loci, with 1 centiRay (cR) corresponding to an average of approximately 100 kb. The RH map, together with an accompanying World-Wide Web server, makes it possible for any investigator to rapidly localize sequences in the mouse genome. Together with the previously constructed genetic map and a YAC-based physical map reported in a companion paper, the fundamental maps required for mouse genomics are now available.  相似文献   
943.
The enzymic activity of Mg2+- or Ca2+-stimulated ATPase from Escherichia coli was inhibited by one of the troponin components, TN-I, and by mitochondrial ATPase inhibitor (F1-inhibitor). The inhibitory ability of component TN-I against Mg2+-stimulated AtPase activity was lost after digestion of component TN-I with trypsin. The Mg2+-stimulated ATPase activity inhibited by component TN-I was completely restored by the addition of another troponin component TN-C.  相似文献   
944.
B Beckman  J W Fisher 《Experientia》1979,35(12):1671-1672
Erythroid burst forming units (BFU-E) were much more sensitive to the beta-2 selective adrenergic drug, salbutamol, than erythroid colony forming units (CFU-E) in an in vitro study of erythroid progenitor cells.  相似文献   
945.
In humans, as well as in mice, fed on high carbohydrate diets, there was a significant sex difference in the plasma tirglycerides in that males had higher levels than females. This was mainly due to the difference in their removal rate of circulating triglycerides in the animals of both sexes. In mice, males had higher levels of liver triglycerides as well as higher rate of incorporation of U- 14C-glucose into liver triglycerides when compared to females.  相似文献   
946.
The somatostatin content in pancreatic islets of obese-hyperglycemic mice was much lower than in the islets of normal mice. Also the release of somatostatin was decreased from the islets obtained from the obese-hyperglycemic mice. Tissue culture for 1 week changed neither the content of, nor the amount of somatostatin released from, the pancreatic islets.  相似文献   
947.
Mild acidic treatment increases the rheumatoid factor titre of some sera and synovial fluids (SF) in rheumatoid arthritis (RA), juvenile RA (JRA) and most frequently in rheumatoid vasculitis. This unmasking of 'hidden' RF in serum and SF samples correlated with the RF-immune complexes (RF-IC) and complexed C4 present in the 3% polyethylene glycol (PEG) precipitates, indicating that by means of 'hidden' RF measurements RF-ICs are possibly detected. This method seems to provide a diagnostic tool for detecting RF-ICs in RA and other related diseases.  相似文献   
948.
949.
950.
Pigment granules in choroidal melanophores of the albino goldfish contained fine particulate materials which were in various degrees aggregated in clumps. Tyrosinase was considered to be present in an inhibited state in these pigment granules.  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