全文获取类型
收费全文 | 3603篇 |
免费 | 404篇 |
出版年
2022年 | 19篇 |
2021年 | 49篇 |
2020年 | 27篇 |
2019年 | 43篇 |
2018年 | 73篇 |
2017年 | 53篇 |
2016年 | 104篇 |
2015年 | 139篇 |
2014年 | 174篇 |
2013年 | 199篇 |
2012年 | 253篇 |
2011年 | 270篇 |
2010年 | 182篇 |
2009年 | 169篇 |
2008年 | 222篇 |
2007年 | 210篇 |
2006年 | 187篇 |
2005年 | 171篇 |
2004年 | 176篇 |
2003年 | 179篇 |
2002年 | 168篇 |
2001年 | 51篇 |
2000年 | 41篇 |
1999年 | 51篇 |
1998年 | 49篇 |
1997年 | 40篇 |
1996年 | 43篇 |
1995年 | 48篇 |
1994年 | 35篇 |
1993年 | 48篇 |
1992年 | 57篇 |
1991年 | 41篇 |
1990年 | 48篇 |
1989年 | 35篇 |
1988年 | 28篇 |
1987年 | 17篇 |
1986年 | 26篇 |
1985年 | 26篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 22篇 |
1981年 | 19篇 |
1980年 | 17篇 |
1979年 | 16篇 |
1978年 | 18篇 |
1977年 | 19篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1970年 | 10篇 |
1967年 | 10篇 |
排序方式: 共有4007条查询结果,搜索用时 15 毫秒
21.
22.
Edmond A. Goidl Christiane Samarut Ansbert Schneider-Gadicke Neal L. Hochwald G.Jeanette Thorbecke Gregory W. Siskind 《Cellular immunology》1984,85(1):25-33
Using hapten-reversible inhibition of plaque formation as an assay for auto-anti-idiotype antibody (anti-Id) and as a means for following idiotype (Id) expression, we have obtained evidence that following immunization with trinitrophenyl (TNP) conjugates (a) there are differences in Id expression in the anti-TNP antibody response to different TNP conjugates although there is some overlap; (b) different strains, although showing some differences in Id expression, tend to produce cross-reactive Ids, thus no obvious allotype linked inheritance of Id expression is observed in this heterogeneous immune response; (c) the auto-anti-Id produced following immunization with TNP-Brucella abortus or TNP-Ficoll tends to be of the IgG2a and IgG2b isotypes. 相似文献
23.
24.
Cathepsin B, H, L and D activities in liver lysosomes were compared between species. Although cathepsin B and D were detected in bovine, pig, chicken and rat liver, striking species differences were evident for cathepsin H and L. Cathepsin L activity was particularly high in chicken lysosomal extracts, but could not be detected in bovine and pig extracts. Whereas there was no significant cathepsin H activity in bovine extracts, rat liver lysosomal extracts contained large amounts of cathepsin H activity. 相似文献
25.
Heterogeneity in the map distance between X-linked agammaglobulinemia and a map of nine RFLP loci 总被引:4,自引:1,他引:3
J. Ott E. J. B. M. Mensink A. Thompson J. D. L. Schot R. K. B. Schuurman 《Human genetics》1986,74(3):280-283
Summary In nine family pedigrees in which X-linked agammaglobulinemia (XLA) is segregating, a multi-point linkage analysis has been carried out. In each family, the map distance, d, between XLA and a fixed point in a known map of nine RFLP loci on the X chromosome was estimated by calculating the log likelihoods, L(d). Using a new method, the 10-point likelihood was approximated by appropriately combining three 4-point likelihoods. Homogeneity tests (admixture tests) were performed showing clear evidence for heterogeneity of XLA. 相似文献
26.
Jörg Hacker Manfred Ott Günter Schmidt Richard Hull Werner Goebel 《FEMS microbiology letters》1986,36(2-3):139-144
Abstract The genetic determinant coding for the P-specific F8 fimbriae was cloned from the chromosome of the Escherichia coli wild-type strain 2980 (O18:K5:H5:F1C, F8). The F8 determinant was further subcloned into the Pst I site of pBR322 and a restriction map was established. In a Southern hybridization experiment identity between the chromosomally encoded F8 determinant of 2980 and its cloned counterpart was demonstrated. The cloned F8 fimbriae and those of the wild type strain consist of a protein subunit of nearly 20 kDa. F8 fimbriated strains were agglutinated by an F8 polyclonal antiserum, caused mannose-resistant hemagglutination and attached to human uroepithelial cells. The cloned F8 determinant was well expressed in a variety of host strains. 相似文献
27.
A cDNA clone containing the entire coding sequence of a mouse H-2Kd histocompatibility antigen 总被引:14,自引:4,他引:10
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jean-Louis Lalanne Christiane Delarbre Gabriel Gachelin Philippe Kourilsky 《Nucleic acids research》1983,11(5):1567-1577
We have isolated a cDNA clone carrying a 1560 bp long insert which contains the entire coding and 3' untranslated regions of an H-2K(d) mouse histocompatibility antigen. Its sequence and overal features are described. They point to the existence of unique properties of DNA sequences associated with the H-2K(d) antigen. 相似文献
28.
Poly(2-methylthio-7-deazainosinic acid)--hydrophobic stabilization of polynucleotide secondary structure by the 2-methylthio group. 总被引:1,自引:1,他引:0
下载免费PDF全文
![点击此处可从《Nucleic acids research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Poly(2-methylthio-7-deazainosinic acid) [poly(ms2c7I)] was enzymatically synthesized by polymerization of 2-methylthio-7-deazainosine 5'-diphosphate with polynucleotide phosphorylase from Micrococcus luteus in high yield. The homopolymer shows much higher thermal stability than its parent polynucleotides poly(7-deazainosinic acid) [poly(c7I)] and poly(I). Its sigmoidal melting curve and pronounced hypochromicity imply a rigid, ordered structure. Poly(ms2c7I), like poly(2-methylthio-inosinic acid) [poly(ms2I)], does not form a complex with poly(C) because of the bulky 2-methylthio substituent. On the other hand, two poly(ms2c7I) strands form very rigid triple strands with poly(A). Different from poly(I) and poly(c7I) the homopolymer poly(ms2c7I) is very stable against cleavage by nuclease S1 and ribonuclease T2 as expected from its rigid secondary structure. 相似文献
29.
The composition of 3 species of genus Cistus L. has been analysed and compared: C. labdaniferus L. contains essentially compounds of labdane type, namely labdane-8, 15, 19-triol whose structure has been confirmed; C. monspeliensis L. contains almost exclusively compounds having a new squeleton, the cistane, with a cis-junction of A and B; no cyclic diterpenes have been isolated from C. salvifolius L. which has been found rich in unsaturated aliphatic acids one of which is a mono conjugated triethylenic acid. 相似文献
30.