全文获取类型
收费全文 | 733篇 |
免费 | 106篇 |
出版年
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 23篇 |
2014年 | 35篇 |
2013年 | 37篇 |
2012年 | 53篇 |
2011年 | 46篇 |
2010年 | 31篇 |
2009年 | 31篇 |
2008年 | 43篇 |
2007年 | 37篇 |
2006年 | 33篇 |
2005年 | 41篇 |
2004年 | 37篇 |
2003年 | 27篇 |
2002年 | 30篇 |
2001年 | 13篇 |
2000年 | 19篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 4篇 |
1996年 | 9篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 18篇 |
1991年 | 12篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1981年 | 9篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1974年 | 4篇 |
1973年 | 8篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1969年 | 4篇 |
1966年 | 5篇 |
1937年 | 3篇 |
排序方式: 共有839条查询结果,搜索用时 15 毫秒
1.
M Shadidy X Caubit R Olsen O M Seternes U Moens S Krauss 《Biochimica et biophysica acta》1999,1446(3):295-307
We have identified mouse and human FKBP60, a new member of the FKBP gene family. FKBP60 shares strongest homology with FKBP65 and SMAP. FKBP60 contains a hydrophobic signal peptide at the N-terminus, 4 peptidyl-prolyl cis/trans isomerase (PPIase) domains and an endoplasmic reticulum retention motif (HDEL) at the C-terminus. Immunodetection of HA-tagged FKBP60 in NIH-3T3 cells suggests that FKBP60 is segregated to the endoplasmic reticulum. Northern blot analysis shows that FKBP60 is predominantly expressed in heart, skeletal muscle, lung, liver and kidney. With N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide as a substrate, recombinant GST-FKBP60 is shown to accelerate effectively the isomerization of the peptidyl-prolyl bond. This isomerization activity is inhibited by FK506. mFKBP60 binds Ca2+ in vitro, presumably by its C-terminal EF-hand Ca2+ binding motif, and is phosphorylated in vivo. hFKBP60 has been mapped to 7p12 and/or 7p14 by fluorescence in situ hybridization (FISH). 相似文献
2.
3.
4.
A nuclear protein, present in carrot meristems and rapidly proliferating cultured cells of carrot (Daucus carota L.) has been identified by the use of a monoclonal antibody (MAb 21D7). By combining the techniques of two-dimensional polyacrylamide gel analysis and blotting separated proteins onto nitrocellulose sheets, it was shown that the antibody detected a single polypeptide of apparent molecular mass (M
r) of 45000 and an isoelectric focusing point (pI) of 6.7. This protein was found by subcellular fractionation and immunofluorescence to be highly concentrated in the nucleoli of somatic and zygotic embryos of a wide range of plants. It was not detectable in logarthmically growing cells ofEscherichia coli, yeast, embryos ofDrosophila melanogaster or cultured C3H mouse cells. These data indicate that this protein is a highly conserved non-histone protein associated with nuclei of rapidly dividing plant cells.Abbreviations
M
r
apparent molecular mass
- Da
dalton
- Ig
immunoglobulins
- MAb
monoclonal antibody
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- 2-D gel
two-dimensional gel electrophoresis
- 2,4-D
2,4-dichlorophenoxyacetic acid 相似文献
5.
It has been observed that each strain of the Pseudomonas aeruginosa species harbours the so-called polyagglutinable antigen (PA). Some strains may produce it in a form which is linked to the core moiety of lipopolysaccharide (LPS) and this type of PA can thus be detected by passive haemagglutination using the isolated LPS as coating antigen. Other strains synthesize PA exclusively in a free form, which is also coextractable with LPS, its presence can, however, be demonstrated by the haemagglutination inhibition test. From a polyagglutinable strain of P. aeruginosa an R-type LPS was isolated having the core-linked PA. This LPS preparation was highly immunogenic with regard to its PA moiety. The core-bound PA seems to exert an immunosuppression on the core region, hence, the polyagglutinable strains isolated from cystic fibrosis patients only engender anti-PA antibodies, whereas antibodies against both, side chain and core region of LPS, are not engendered. The mucoid exopolysaccharide also contains the PA which could possibly play an important role in the patient by protecting P. aeruginosa cells against anti-PA antibodies. 相似文献
6.
7.
Lipopolysaccharides of Thiocystis violacea, Thiocapsa pfennigii, and Chromatium tepidum, species of the family Chromatiaceae. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The lipopolysaccharides (LPS) of three species of purple sulfur bacteria (Chromatiaceae), Thiocystis violacea, Thiocapsa pfennigii, and the moderately thermophilic bacterium Chromatium tepidum, were isolated. The LPS of Thiocystis violacea and Chromatium tepidum contained typical O-specific sugars, indicating O-chains. Long O-chains were confirmed for these species by sodium deoxycholate gel electrophoresis of their LPS. Thiocapsa pfennigii, however, had short or no O-chains. The core region of the LPS of all three species comprised D-glycero-D-mannoheptose as the only heptose and 2-keto-3-deoxyoctonate. The lipid A, obtained from the LPS by mild acid hydrolysis, contained glucosamine as the main amino sugar. Amide-bound 3-hydroxymyristic acid was the only hydroxy fatty acid. The main ester-bound fatty acid in all lipid A fractions was 12:0. Mannose and small amounts of 2,3-diamino-2,3-dideoxy-D-glucose were common constituents of the lipid A of the three Chromatiaceae species investigated. All lipid A fractions were essentially free of phosphate. 相似文献
8.
The primase activity of DNA polymerase alpha from calf thymus 总被引:14,自引:0,他引:14
The nearly homogeneous 9 S DNA polymerase alpha from calf thymus contains a primase activity that allows priming of DNA synthesis on single-stranded templates in the presence of ribonucleoside triphosphates. Both on synthetic and natural single-stranded templates, RNA primers of 8-15 nucleotides in length are formed. In the absence of dNTPs, primers of some hundred nucleotides in length are observable. ATP and/or GTP are required for the priming reaction. UTP and CTP cannot initiate the RNA synthesis. M13 single-stranded DNA can be converted to the nicked double helical form upon primase-primed replication by the 9 S enzyme. Priming occurs mostly at specific sites on the M13 genome and replication products of up to 6000 nucleotides in length are formed. In the presence of the single-stranded DNA binding protein from Escherichia coli, specificity of priming is strongly increased. The primase is inhibited by salt and actinomycin; it is insensitive to alpha-amanitin and N-ethylmaleimide. Due to the strong complex formation between DNA polymerase and primase, it has not been possible to separate the two activities of the multisubunit 9 S enzyme. 相似文献
9.
Christopher W. Lawrence Beth R. Krauss Roshan B. Christensen 《Mutation research》1985,150(1-2):211-216
Previously isolated mutations in baker's yeast, Saccharomyces cerevisiae, that impair induced mutagenesis were all identified with the aid of tests that either exclusively or predominantly detect base-pair substitutions. To avoid this bias, we have screened 11 366 potentially mutant clones for UV-induced reversion of the frameshift allele, his4–38, and have identified 10 mutants that give much reduced yields of revertants. Complementation and recombination tests show that 6 of these carry mutations at the previously known REV1, REV1 and REV3 loci, while the remaining 4 define 3 new genes, REV4 (2 mutations), REV5 and REV6. The rev4 mutations are readily suppressed in many genetic backgrounds and, like the rev5 mutation, impart only a limited deficiency for induced mutagenesis: it is likely, therefore that the REV4+ and REV5+ gene functions are only remotely concerned with this process. The rev6 mutants have a more general deficiency, however, as well as marked sensitivity to UV and an increased spontaneous mutation rate, properties that suggest the REV6 gene is directly involved in mutation induction. The REV5 gene is located about 1 cM proximal to CYC1 on chromosome X. 相似文献
10.
Modulation of apolipoprotein B antigenic determinants in human low density lipoprotein subclasses 总被引:4,自引:0,他引:4
B Teng A Sniderman R M Krauss P O Kwiterovich R W Milne Y L Marcel 《The Journal of biological chemistry》1985,260(8):5067-5072
To investigate the effect of low density lipoprotein (LDL) heterogeneity on the conformation of LDL apolipoprotein B (apo-B), the immunoreactivities of 6 monoclonal antibodies against LDL apo-B were measured in 3 LDL subfractions isolated by equilibrium density gradient ultracentrifugation. To ensure a broad range of LDL particles, the LDL subfractions were prepared from normal subjects and patients with hyperapobetalipoproteinemia. With 3 of the antibodies, 1D1, 5E11, and 3A10, LDL fractions 1 (the most buoyant), 2 (the intermediate), and 3 (the densest) were equally immunoreactive and competed similarly with reference whole LDL. In contrast, with 3 other antibodies, 2D8, 3F5, and 4G3, fraction 1 was significantly more reactive than fraction 3; that is for each in turn, 290, 250, and 150% more of the densest LDL protein was required to achieve the same displacement as with fraction 1. Further, the immunoreactivities of the 3 LDL fractions with antibodies 2D8, 3F5, and 4G3 were negatively correlated with their LDL cholesterol to LDL protein ratio with r values of 0.727, 0.898, and 0.870, respectively, suggesting that as LDL particle size decreases, the conformation of the LDL apo-B changes progressively. It is of interest that the antigenic determinants recognized by 3F5 and 4G3 are close to the LDL receptor recognition site on LDL apo-B. Therefore, it is possible that the reduced immunoreactivity of these determinants in dense LDL may be the in vitro correlate of the reduced fractional catabolics rate of dense LDL compared to buoyant LDL previously observed in vivo. 相似文献