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   737篇
  免费   41篇
  2022年   6篇
  2020年   3篇
  2019年   10篇
  2018年   12篇
  2017年   8篇
  2016年   6篇
  2015年   12篇
  2014年   15篇
  2013年   44篇
  2012年   46篇
  2011年   34篇
  2010年   17篇
  2009年   16篇
  2008年   20篇
  2007年   30篇
  2006年   20篇
  2005年   30篇
  2004年   38篇
  2003年   30篇
  2002年   37篇
  2001年   19篇
  2000年   26篇
  1999年   16篇
  1998年   8篇
  1997年   6篇
  1996年   11篇
  1995年   12篇
  1994年   5篇
  1993年   5篇
  1992年   17篇
  1991年   24篇
  1990年   26篇
  1989年   15篇
  1988年   17篇
  1987年   9篇
  1986年   13篇
  1985年   10篇
  1984年   14篇
  1983年   8篇
  1982年   5篇
  1981年   8篇
  1979年   12篇
  1978年   4篇
  1977年   8篇
  1975年   4篇
  1974年   12篇
  1973年   6篇
  1972年   3篇
  1971年   8篇
  1968年   3篇
排序方式: 共有778条查询结果,搜索用时 15 毫秒
751.
752.
The immunohistochemical distribution of 15 blood coagulation factors in the germinal centers (GCs) of human Peyer's patches (PPs) was studied. Although factor VIII, active alpha-thrombin, and fibrinogen were hardly evident in the GCs, the majority of coagulation factors, such as kallikrein, high-molecular-weight kininogen, factors XII, X, IX, VII, V, XIIIa and XIIIb, prothrombin, anti-thrombin III and inactive alpha-thrombin were found, showing a lace-like staining pattern similar to that obtained with a monoclonal antibody, R4/23, specific for follicular dendritic cells (FDCs) in the GCs. By immunoelectron microscopy, positive reactions for factor X and XIIIa were found on the surfaces of FDCs, GC cells, and/or in the intercellular spaces of GCs, being especially marked on the surface of the labyrinth-like structure of FDCs. It is concluded that a majority of coagulation factors are localized in the GCs of human PPs. Furthermore, it is suggested that some of these coagulation factors have a close topographical relationship with FDCs.  相似文献   
753.
A cDNA clone encoding NS3-glycoprotein was isolated from stigmasof Brassica campestris. NS-glycoproteins correspond to the SLRI-glycoproteinsof B. oleracea and are highly conserved within the species.These data suggest that the NS-glycoproteins may play a rolein discrimination between species in the fertilization systemof Brassica. (Received September 4, 1992; Accepted November 9, 1992)  相似文献   
754.
755.
Ohno  Tamio  Hata  Keiko  Baba  Taisuke  Io  Fusayo  Kobayashi  Misato  Horio  Fumihiko  Nishimura  Masahiko 《Mammalian genome》2012,23(11):764-769

Consomic strains, in which one chromosome is derived from a donor strain and the other chromosomes are derived from the recipient strain, provide a powerful tool for the dissection of complex genetic traits. In this study we established ten consomic strains (A-2SM, A-6SM, A-11SM, A-12SM, A-13SM, A-15SM, A-17SM, A-18SM, A-19SM, A-YSM) using the SM/J strain as the donor and the A/J strain as the recipient; these are the parental strains of a set of SMXA recombinant inbred (RI) strains that we had developed previously. We analyzed body weights and blood lipid levels in the consomic and parental strains. The mean values for each trait showed a continuous range of variation in the consomic strains suggesting that they are controlled by multiple genes. We previously identified suggestive QTLs for body weight on chromosome 6 in SMXA RI strains and (SM/J × A/J)F2 mice. The observation that the A-6SM consomic strain had a significantly lower mean body weight than the A/J strain supports the presence of this QTL on chromosome 6. Similarly, the higher blood triglyceride level in the A-11SM strain shows the existence of a previously mapped QTL on chromosome 11, and the A-12SM strain provides evidence of a QTL for blood total cholesterol level on chromosome 12. These consomic strains, along with the previously developed set of SMXA RI strains from A/J and SM/J mice, offer an invaluable and powerful resource for the analysis of complex genetic traits in mice.

  相似文献   
756.
Vitelline-coat lysins from two species of marine mollusc of the genus Tegula, Tegula lischkei and Tegula sp., were purified and their properties compared with those of Tegula pfeifferi. Cross-reaction tests among these three species proved that the lysin action on the vitelline coat was species specific. Each of the lysins from these three species is a single, basic polypeptide with a molecular weight of 16000-17000 and an isoelectric point of pH 10.5. All of them share a common antibody recognition site(s) for the anti-T. pfeifferi lysin antibody. Their amino acid sequences were analyzed using intact lysins and peptides separated by reverse phase high-performance liquid chromatography after V8 proteinase digestion. The amino acid sequences of the N-terminus (Nos 1-66) from the three species showed 98% homology, and those of the C-terminus (Nos 91-118) showed 89% homology. It was concluded that the species specificity of the vitelline coat lysin appears to be determined by a sequence of 24 residues (Nos 67-90) in the middle region of the molecule.  相似文献   
757.
758.
An oligonucleotide spin-labelled with 4-amino-2,2,6,6-tetramethylpiperidine-N-oxyl (4-amino-TEMPO) at the internucleotide bond (d-Tp(L)TpTpTpT) prepared by oxidation of the pentanucleotide containing the H-phosphonate diester (d-Tp(H)TpTpTpT) in the presence of 4-amino-TEMPO, was separated and identified by high-performance, reverse-phase liquid chromatography combined with detection by electron spin resonance spectroscopy. This spin-labelled oligonucleotide produced a triplet with the slightly broadened M1 = — I ESR component, while a triplet with almost equal intensities was obtained from the spin-label. The M1 = —1 component from the labelled oligonucleotide was further broadened in the presence of poly(A) which forms a complementary double strand with this molecule.  相似文献   
759.
Reverse-phase high-performance liquid chromatography on a column of trimethylsilylated silica gel (TSK-TMS 250) was utilized for the isolation of the subunit proteins of pertussis toxin (PT). Recovery up to 95% was obtained for each of the five distinct subunits with a high degree of homogeneity as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. None of the individual subunit proteins exhibited PT-related leukocytosis-promoting activity or the ability to bind haptoglobin; however, these activities were partially restored when an equimolar mixture of the isolated subunit in 6 M guanidine-HCl was diluted from this chaotropic agent. The complex macromolecule subsequently isolated from the mixture displayed subunit composition and biological activities indistinguishable from those of native PT, indicating that the toxin molecule had been reassembled.  相似文献   
760.
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