全文获取类型
收费全文 | 1165篇 |
免费 | 126篇 |
国内免费 | 1篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 17篇 |
2020年 | 17篇 |
2019年 | 14篇 |
2018年 | 21篇 |
2017年 | 20篇 |
2016年 | 21篇 |
2015年 | 54篇 |
2014年 | 46篇 |
2013年 | 56篇 |
2012年 | 61篇 |
2011年 | 82篇 |
2010年 | 53篇 |
2009年 | 43篇 |
2008年 | 80篇 |
2007年 | 66篇 |
2006年 | 70篇 |
2005年 | 58篇 |
2004年 | 62篇 |
2003年 | 52篇 |
2002年 | 60篇 |
2001年 | 18篇 |
2000年 | 20篇 |
1999年 | 16篇 |
1998年 | 18篇 |
1997年 | 16篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 11篇 |
1993年 | 14篇 |
1992年 | 14篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1971年 | 4篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1963年 | 5篇 |
1957年 | 4篇 |
1945年 | 3篇 |
1943年 | 3篇 |
排序方式: 共有1292条查询结果,搜索用时 31 毫秒
1.
Isocitrate lyase inEscherichia coli and inAcinetobacter calcoaceticus is phosphorylated when the cells are grown with acetate as the sole carbon source in low-phosphate mineral salts medium containing32P inorganic phosphate. The level of32P incorporation into the enzyme in both microorganisms appears to be constant throughout the entire growth cycle. Further, theresults of immunoblots and rocket immunoelectrophoresis suggest that the amount of isocitrate lyase protein, although at different levels in each microorganism, also remains constant throughout the growth cycle. 相似文献
2.
3.
Cecilia PC Soh Alastair SR Donald James Feeney Walter TJ Morgan Winifred M Watkins 《Glycoconjugate journal》1989,6(3):319-332
The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and1H-500 MHz NMR spectroscopy. In Sda serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity. 相似文献
4.
Anna L. Ballard Alastair G. McEwan David J. Richardson J. Baz Jackson Stuart J. Ferguson 《Archives of microbiology》1990,154(3):301-303
Rhodobacter capsulatus strain BK5 possesses a membrane bound respiratory nitrate reductase rather than the periplasmic enzyme found in other strains. The enzyme in strain BK5 is shown to be both functionally and structurally related to the nitrate reductase of Paracoccus denitrificans and Escherichia coli.Abbreviation TMAO
trimethylamine-N-oxide 相似文献
5.
6.
Summary The effects of a non-ionic surfactant, Pluronic F-68, on growth of microbial cell cultures have been studied. Growth ofSaccharomyces cerevisiae at 30°C or 37°C as measured by viable cell counts was unaffected by culture with pluronic. However, corresponding absorbance measurements forS. cerevisiae incubated with 5–10% pluronic were lower than controls at both temperatures. Absorbance ofE. coli cultures was also significantly reduced by incubation with 5.0–10.0% pluronic at both temperatures although viable counts again revealed no significant inhibition of growth. 相似文献
7.
Molecular organisation of the quinic acid utilization (QUT) gene cluster in Aspergillus nidulans 总被引:9,自引:0,他引:9
Alastair R. Hawkins Heather K. Lamb Melanie Smith John W. Keyte Clive F. Roberts 《Molecular & general genetics : MGG》1988,214(2):224-231
Summary The functional integrity of the QUTB gene (encoding quinate dehydrogenase) has been confirmed by transformation of a qutB mutant strain. The DNA sequence of the contiguous genes QUTD (quinate permease), QUTB and QUTG (function unknown) has been determined and analysed, together with that of QUTE (catabolic 3-dehydroquinase). The QUTB sequence shows significant homology with the shikimate dehydrogenase function of the complex AROM locus of Aspergillus nidulans, and with the QA-3 quinate dehydrogenase and QA-1S (repressor) genes of Neurospora crassa. The QUTD gene shows strong homology with the N. crassa QA-Y gene and QUTG with the QA-X gene. QUTD, QUTB, and QUTG, QUTE form two pairs of divergently transcribed genes, and conserved sequence motifs identified in the two common 5 non-coding regions show significant homology with UAS
GAL
and UAS
QA
sequences of the Saccharomyces cerevisiae and N. crassa Gal and QA systems. In addition, conserved 5 sequences homologous to the mammalian CAAT box are noted and a previously unreported conserved 22 nucleotide motif is presented. 相似文献
8.
Escherichia coli isocitrate lyase (EC 4.1.3.1.) can be phosphorylated in vitro by an ATP-dependent reaction. The enzyme becomes phosphorylated by an endogenous kinase when partially purified sonic extracts are incubated with [gamma-32P]ATP. Treatment of isocitrate lyase with diethyl pyrocarbonate, a histidine-modifying reagent, blocked incorporation of [32P]phosphate from [gamma-32P]ATP. The isoelectric point of the enzyme was altered by treatment with phosphoramidate, a histidine phosphorylating agent, which suggests that isocitrate lyase can be phosphorylated at a histidine residue(s). Immunoprecipitated 32P-labeled isocitrate lyase was subjected to alkaline hydrolysis, mixed with chemically synthesized phosphohistidine standards, and analyzed by anion exchange chromatography. Characterization of the phosphoamino acid was based on the demonstration that the 32P-labeled product from alkali-hydrolyzed isocitrate lyase comigrated with synthetic 1-phosphohistidine. In addition, loss of catalytic activity after treatment with potato acid phosphatase indicates that catalytically active isocitrate lyase is the phosphorylated form of the enzyme. 相似文献
9.
10.