全文获取类型
收费全文 | 8394篇 |
免费 | 434篇 |
国内免费 | 6篇 |
出版年
2022年 | 40篇 |
2021年 | 75篇 |
2020年 | 44篇 |
2019年 | 49篇 |
2018年 | 92篇 |
2017年 | 80篇 |
2016年 | 147篇 |
2015年 | 199篇 |
2014年 | 243篇 |
2013年 | 822篇 |
2012年 | 430篇 |
2011年 | 517篇 |
2010年 | 295篇 |
2009年 | 277篇 |
2008年 | 494篇 |
2007年 | 505篇 |
2006年 | 515篇 |
2005年 | 524篇 |
2004年 | 484篇 |
2003年 | 474篇 |
2002年 | 541篇 |
2001年 | 97篇 |
2000年 | 85篇 |
1999年 | 96篇 |
1998年 | 139篇 |
1997年 | 106篇 |
1996年 | 101篇 |
1995年 | 97篇 |
1994年 | 84篇 |
1993年 | 121篇 |
1992年 | 94篇 |
1991年 | 60篇 |
1990年 | 46篇 |
1989年 | 69篇 |
1988年 | 51篇 |
1987年 | 53篇 |
1986年 | 45篇 |
1985年 | 49篇 |
1984年 | 60篇 |
1983年 | 38篇 |
1982年 | 73篇 |
1981年 | 56篇 |
1980年 | 58篇 |
1979年 | 29篇 |
1978年 | 43篇 |
1977年 | 28篇 |
1976年 | 34篇 |
1974年 | 24篇 |
1973年 | 25篇 |
1972年 | 24篇 |
排序方式: 共有8834条查询结果,搜索用时 93 毫秒
351.
Akira Sakurai Saburo Tamura Naohiko Yanagishima Chikashi Shimoda Michio Hagiya Narao Takao 《Bioscience, biotechnology, and biochemistry》2013,77(1):231-232
5-Fluorotryptophan (5FT), indolmycin (IM), 4-fluorotryptophan and 7-azatryptophan were found on screening to be tryptophan antagonists among various chemically synthesized and naturally occurring tryptophan analogues for the isolation of l-tryptophan (l-Trp) producing mutants of Bacillus subtilis K.From among 5FT resistant mutants, potent l-Trp producers were obtained using an improved isolation medium. Growth of the isolated 5FT-resistant l-Trp producer, AJ 11709, was inhibited by IM. From among 5FT and IM resistant mutants, the best strain, AJ 11979, which produced 9.0 g/liter of l-Trp from 13% glucose on 120hr cultivation, was selected. 相似文献
352.
Akira Matsuyama Yoshishige Okazawa Mitsuo Namiki 《Bioscience, biotechnology, and biochemistry》2013,77(5):367-376
The effects of irradiation in the JRR-1 (Japan Research Reactor No. 1, a homogeneous light water nuclear reactor; max. power, 50 KW) on microorganisms such as bacterial and fungal spores and yeast cells were investigated in comparison with those of 60Co gamma radiation. As far as the lethal effect was concerned the dose rate of radiation in the experimental hole No. 16 of the JRR-1 was equivalent to 3.0×l06~3.4×l06 r/hr with 60Co gamma radiation, and a ratio of the neutron effect to the gamma radiation effect on microorganisms in this hole was estimated to be approximately 3~5.4. The results different from those with gamma radiation were obtained in experiments such as post-NaCl treatment and spore germination. The considerable contribution of fast neutrons to the total biological effect of neutrons, in comparison with the thermal neutron effect, could be presumed from the microbiological experiments with the help of physical and chemical data. Morphological changes in post-irradiation growth were observed by means of phase contrast microscopy. No specific aftereffect was found. 相似文献
353.
Osamu Yamada Akira Kurozumi Fumio Futatsuya Kensaku Ito Shuichi Ishida Katsura Munakata 《Bioscience, biotechnology, and biochemistry》2013,77(7):1467-1471
Some benzophenones substituted with methyl, methoxy, hydroxy or halogen groups inhibited growth and induced chlorosis in various plants. The structure activity relationships about the chlorosis-inducing activity and the growth inhibitory activity of the 3-methyl-benzophenones were well expressed by use of hydrophobic contant π, and Hammett’s σ. The highest selectivity for phytotoxic activities against barnyardgrass and the rice plant was with 3,3′-dimethyl-4-methoxybenzophenone (Methoxyphenone). 相似文献
354.
Akira Kimura Jun’ichi Kawanami Hideo Otsuka 《Bioscience, biotechnology, and biochemistry》2013,77(12):1434-1440
Lipids were extracted with chloroform-methanol from Streptomyces sioyaensis and fractionated on a silicic acid column. Lipids of Streptomyces sioyaensis were mainly composed of neutral lipids, cardiolipin, phosphatidylethanolamines, phosphatidylinositolmonomanno- side and a new lysine-containing lipid. 相似文献
355.
356.
Hideoki Tanaka Hidekatsu Maeda Hideo Suzuki Akira Kamibayashi Kenzo Tonomura 《Bioscience, biotechnology, and biochemistry》2013,77(6):1429-1438
A photosynthetic bacterium, which can grow photosynthetically on benzoate, was isolated from sewage mud. Various kinds of aromatic compounds including heterocyclic aromatic compounds were photometabolized by the washed cells grown photosynthetically on benzoate with no lag period. Among these, thiophene-2-carboxylate was metabolized most rapidly to its (+)-tetrahydro derivative. The same strain could also grow on succinate under photosynthetic conditions. However, thiophene-2-carboxylate was only photometabolized after a long lag period by the washed cells grown photosynthetically on succinate, and the metabolite was not its (+)-tetrahydro derivative but (+)-3-hydroxytetrahydrothiophene-2-carboxylate. In the presence of chloramphenicol, an inhibitor of protein synthesis, the photometabolism of thiophene-2-carboxylate by the washed cells grown photosynthetically on benzoate was not affected at all, but the photometabolism of the same substrate by the washed cells grown photosynthetically on succinate was completely inhibited. These results indicate that a reduction system of broad substrate specificity for aromatic rings is already present in the benzoate-grown cells but absent in the succinate-grown cells. It seems that such a reduction system for aromatic rings is induced by an aromatic substrate. 相似文献
357.
358.
Yukio Satomura Susumu Oi Akira Sawada 《Bioscience, biotechnology, and biochemistry》2013,77(3):194-200
Intracellular lipase of the fungus Sclerotina Libertiana Fcl. could be formed powerfully by washed mycelium during shaking in a plain buffer solution, just as well as in the case of shaking culture. Experiments showed revealed it to be favourable to set the mycelium in the experiment harvested at the end of its stationary phase of growth, and that the addition of various respiratory carbon sources had inhibiting effects, while several surface active agents and some enzyme preparations accelerating effects on the lipase formation. Also, the quality and the quantity of consumed cell-materials in the shaking experiment were investigated in relation to lipase formation. 相似文献
359.
360.
Hiroshi Saito Akira Misaki Tokuya Harada 《Bioscience, biotechnology, and biochemistry》2013,77(11):1683-1689
Succinoglucan, a succinylated polysaccharide produced by Alcaligenes faecalis var. myxogenes 10C3, was partially hydrolyzed with acid. Fractionation of the neutral oligosaccharides gave cellobiose, gentiobiose, laminaribiose, laminaritriose, 6-O-β-laminaribiosylglucose, 6-O-β-laminaritriosylglucose, and 3-O-β-cellobiosylgalactose, confirming the previous results that the polysaccharide consists of β-(l→3)-linked, (1→4)-linked and (1 →6)-linked d-glucose residues, and β-(1→3)-linked d-galactose residues.Possible structural features of succinoglucan were discussed on the basis of the above and previous results obtained by Smith degradation. 相似文献