全文获取类型
收费全文 | 2173篇 |
免费 | 90篇 |
国内免费 | 1篇 |
出版年
2021年 | 15篇 |
2020年 | 11篇 |
2019年 | 31篇 |
2018年 | 24篇 |
2017年 | 16篇 |
2016年 | 25篇 |
2015年 | 63篇 |
2014年 | 52篇 |
2013年 | 134篇 |
2012年 | 89篇 |
2011年 | 116篇 |
2010年 | 78篇 |
2009年 | 69篇 |
2008年 | 121篇 |
2007年 | 127篇 |
2006年 | 119篇 |
2005年 | 125篇 |
2004年 | 136篇 |
2003年 | 126篇 |
2002年 | 145篇 |
2001年 | 34篇 |
2000年 | 34篇 |
1999年 | 43篇 |
1998年 | 31篇 |
1997年 | 30篇 |
1996年 | 27篇 |
1995年 | 27篇 |
1994年 | 34篇 |
1993年 | 17篇 |
1992年 | 23篇 |
1991年 | 18篇 |
1990年 | 21篇 |
1989年 | 30篇 |
1988年 | 19篇 |
1987年 | 20篇 |
1986年 | 19篇 |
1985年 | 24篇 |
1984年 | 19篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1975年 | 11篇 |
1971年 | 7篇 |
1970年 | 6篇 |
1969年 | 7篇 |
1968年 | 6篇 |
排序方式: 共有2264条查询结果,搜索用时 0 毫秒
91.
92.
93.
94.
Masaru Iizuka Yasuhiko Torii Takehiko Yamamoto 《Bioscience, biotechnology, and biochemistry》2013,77(12):2767-2772
An enzyme which released invertase from cell ghosts of Candida utilis was isolated in an electrophoretically pure state from “Zymolyase.” The molecular weight of the purified enzyme was estimated to be 5.8 × 104, and its isoelectric point was pH 6.9. The enzyme was stable in a pH range from 6.0 to 9.0, and the optimal pH for liberation of invertase from cell ghosts was around 6.0. The activity of the enzyme was competitively inhibited by glucose, mannose, and sucrose. Unlike the starting enzyme preparation, “Zymolyase,” the purified enzyme released invertase without making holes on the surface of the cell ghosts. Various tests were applied, but the specificity of the enzyme was not defined. 相似文献
95.
Existence of an acetyltransferase, which catalizes acetylation of deacetylcephalosporin C to cephalosporin C, was demonstrated for the first time in cell-free extracts of Cephalosporium acremonium. The pH optimum of the enzyme appeared to be 7.0 to 7.5 and the enzyme required essentially Mg2+ as a cofactor for its reaction. The activity of this enzyme was not observed in the cell-free extracts of deacetylcephalosporin C-producing mutants Nos. 20, 29, 36 and 40, but was recovered in a revertant obtained from the mutant No. 40. These results indicate that deacetylcephalosporin C accumulation by these mutants was due to the lack of the acetyltransferase and made it reasonable that the terminal reaction of cephalosporin C biosynthesis in Cephalosporium acremonium proceeded by the catalytic action of acetyltransferase. 相似文献
96.
Yoshikazu Matsumura Toshihiro Nakanishi Masaru Iizuka Takehiko Yamamoto 《Bioscience, biotechnology, and biochemistry》2013,77(2):379-386
1. A trial test was attempted of complete hydrolysis of peptides and proteins into amino acids by enzymes. “Neutral proteinase” of Bacillus subtilis or “Alkalophilic proteinase” of a Streptomyces sp. was used for preliminary digestion of substrate, and a mixture of three aminopeptidases of Bacillus subtilis was employed for subsequent hydrolysis of proteinase digest.2. The oxidized insulin B chain was hydrolyzed completely by the method. Several proteins including enzymes which contained no or less cystine and cysteine were also hydrolyzed almost completely.3. On the other hand, certain glycoproteins were hydrolyzed to leave a few glycopeptides in which all glycomoieties of the proteins were retained. The implications of the results are discussed. 相似文献
97.
Yuzo Yamada Kazuaki Iizuka Kô Aida Teijiro Uemura 《Bioscience, biotechnology, and biochemistry》2013,77(1):97-98
A crude inhibitor for pancreatic lipase was extracted from soybean seeds. The lipase activity decreased curvilinearly with an increase in inhibitor concentration. At a low inhibitor concentration, enhanced inhibition was observed by the co-existence of protein such as bovine serum albumin in the reaction mixture. The lipase activity was inhibited immediately after the addition of inhibitor which did not cause the significant destraction of substrate emulsion. The lipase activities of Aspergillus niger, Rhizopus delemar and castor bean seeds were also inhibited. The inhibition was observed when various oil substrates such as soybean oil, linseed oil, olive oil emulsions and Ediol were used, and the extent of inhibition varied among them. Column chromatography of inhibitor on Sephadex G–100 showed that the molecular weight of a main peak of inhibitor was estimated as about 80,000. 相似文献
98.
Hiroki Hayase Nobumoto Watanabe Chung Liang Lim Toshihiko Nogawa Keisuke Komatsuya Kiyoshi Kita 《Bioscience, biotechnology, and biochemistry》2013,77(4):633-635
Quinomycin A and its derivatives were identified as potent antimalarial (Plasmodium falciparum) agents in a screen of the RIKEN NPDepo chemical library. IC50 values of quinomycin A and UK-63,598 were approximately 100 times lower than that of the antimalarial drug chloroquine. This activity was mitigated by the addition of plasmid DNA, suggesting that these compounds act against parasites by intercalating into their DNA. 相似文献
99.
Yoshio Sugiyama Kazuaki Kitano Toshihiko Kanzaki 《Bioscience, biotechnology, and biochemistry》2013,77(7):1607-1612
The respiratory chain system of Brev. thiogenitalis grown in the presence of copper ions contained cytochromes a, b and c. The cytochrome a was solubilized and purified from the cell-free extracts by means of Triton X-100 and cholate extraction, and DEAE-cellulose chromatography. It was purified about 130-fold from the cell-free extracts and was free from other cytochromes, The purified preparation contained 1.4 mμatom copper and 1.9 mμatom iron per mμmole heme a, respectively, and approximately 5 mμmoles heme a per mg protein. 相似文献
100.
Yoshio Sugiyama Kazuaki Kitano Toshihiko Kanzaki 《Bioscience, biotechnology, and biochemistry》2013,77(8):1837-1847
Cell-free extracts of Brevibacterium thiogenitalis culture grown in the presence of copper catalyzed the oxidation of NADH2 and succinate through an electron transport chain which contained menaquinones and cytochromes a, b and c. On the other hand, extracts of cells grown in the absence of copper lacked cytochromes a and c, and contained cytochrome d.These findings, as well as the results obtained in inhibition experiments, suggest that in copper-deficient cells the major part of NADH2 was oxidized via a bypass in which the electrons were transferred directly from flavoprotein or cytochrome b to molecular oxygen.Electron transport from these substrates to molecular oxygen resulted in ATP synthesis. The average P/O ratios in extracts of the copper-sufficient cells were 0.33 for generated NADH2, 0.20 for added NADH2, and 0.34 for succinate, and those in extracts of the copper-deficient cells were 0.15, 0.13 and 0.21, respectively. In addition, a linear relationship was found between the yield of L-glutamate from acetate and the P/Ο ratios with both NADH2 and succinate as substrates.From these results, it is reasonable to consider that the poor yield of L-glutamate from acetate in copper-deficient cells was due to a reduction in energy supply, which was caused by the low efficiency of oxidative phosphorylation. 相似文献