全文获取类型
收费全文 | 964篇 |
免费 | 83篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 10篇 |
2019年 | 5篇 |
2018年 | 15篇 |
2017年 | 10篇 |
2016年 | 20篇 |
2015年 | 31篇 |
2014年 | 39篇 |
2013年 | 98篇 |
2012年 | 46篇 |
2011年 | 57篇 |
2010年 | 24篇 |
2009年 | 27篇 |
2008年 | 45篇 |
2007年 | 48篇 |
2006年 | 40篇 |
2005年 | 44篇 |
2004年 | 37篇 |
2003年 | 36篇 |
2002年 | 40篇 |
2001年 | 37篇 |
2000年 | 33篇 |
1999年 | 35篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 29篇 |
1991年 | 24篇 |
1990年 | 12篇 |
1989年 | 24篇 |
1988年 | 15篇 |
1987年 | 16篇 |
1986年 | 20篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1972年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有1047条查询结果,搜索用时 15 毫秒
71.
Osao Adachi Kazunobu Matsushita Emiko Shinagawa Minoru Ameyama 《Bioscience, biotechnology, and biochemistry》2013,77(12):3123-3129
Methanol dehydrogenase (MDH) and aldehyde dehydrogenase (ALDH) were purified to a homogenous state from Methylobacillus glycogenes, an obligate methylotroph. MDH (Mr 140,000) was composed of two different subunits (Mr 60,000 and 9,000) forming an α2β2 structure. MDH was indicated as a metalloquinoprotein containing one atom of calcium (Ca) per enzyme molecule. Binding of Ca was so tight that it was hard to remove Ca completely without denaturation of enzyme protein. A partially resolved enzyme resumed its original enzyme activity upon exogenous addition of Ca. Purified ALDH (Mr 144,000) was composed of two identical subunits of molecular mass of 72,000. ALDH was proved to be a quinoprotein in which PQQ is bound covalently. 相似文献
72.
Minoru Ameyama Kenji Tayama Eiji Miyagawa Emiko Shinagawa Kazunobu Matsushita Osao Adachi 《Bioscience, biotechnology, and biochemistry》2013,77(11):2063-2069
A new enzymatic method for microdetermination of ethanol has been established with particulate alcohol dehydrogenase from acetic acid bacteria and applied to the practical purposes. The enzyme had an optimum pH for ethanol oxidation at a fairly acidic region. Trace amounts of ethanol could be assayed by measuring the initial reaction rate as successful as by reading the end point of the reaction. Some advantages in using this enzyme for ethanol determination were pointed out comparing with NAD-linked alcohol dehydrogenase from yeast or horse liver. Impurity in the enzyme preparations, stability of reagents and coexistence of other substances in the assay mixture were not as critical as in NAD-linked enzyme. Acidic samples could also be directly determined for ethanol without preadjustment of sample pH. 相似文献
73.
Osao Adachi Toshikazu Chiyonobu Emiko Shinagawa Kazunobu Matsushita Minoru Ameyama 《Bioscience, biotechnology, and biochemistry》2013,77(11):2057-2062
Crystalline 2-ketogluconate reductase in genus Acetobacter was prepared from cell free extract of Acetobacter ascendens. Crystalline enzyme was purified 13,000-fold with a yield of 15%. Affinity chromatography on blue-dextran Sepharose 4B column successfully purified the enzyme. The enzyme was composed of three identical subunits with a molecular weight of 40,000. Substrate specificity of 2-ketogluconate reductase from two genera of acetic acid bacteria was compared using highly purified enzyme preparations, and it was confirmed that gluconate oxidation activity of the enzyme was intrinsically weak or absent in genus Acetobacter and intense in Gluconobacter. This fact must be a useful criterion for classification of acetic acid bacteria. 相似文献
74.
Dong Ki Park Junji Terao Setsuro Matsushita 《Bioscience, biotechnology, and biochemistry》2013,77(11):2443-2448
Trilinoleoylglycerol (TL) was autoxidized at 37°C in the dark. Monohydroperoxides (MHP) obtained from the oxidized products were analyzed by high performance liquid chromatography (HPLC). Several peaks which appeared in the chromatogram were identified by infrared (IR), gas chromatography mass spectrometry (GC-MS) and enzymatic hydrolysis. Some positional and geometrical isomers of their hydroperoxy fatty acid components were separated using both absorption and reversed phase systems. Furthermore, 1-hydroperoxylinoleoyl-2,3-dilinoleoyl-glycerol and 1,3-dilinoleoyl-2-hydroperoxylinoleoylglycerol were partly separated by HPLC using an absorption system. MHP obtained from autoxidized corn oil, safflower oil and soybean oil were separated into some peaks by HPLC, although resolution into the individual isomers was incomplete. When oxidized oils were subjected to HPLC analysis directly, a linear relationship was observed between the peak areas of MHP and peroxide value in the range of 10 ~ 50 meq/kg. 相似文献
75.
76.
77.
Takane Fujimori Reiko Kasuga Hajime Matsushita Hajime Kaneko Masao Noguchi 《Bioscience, biotechnology, and biochemistry》2013,77(2):303-315
The constituents of the neutral volatiles from air-cured Burley tobacco were studied using distillation, silicic acid column chromatography, preparative gas chromatography and GC–MS. The isolation and identification of 84 compounds are reported of which 27 are newly identified as tobacco constituents and 4 are new natural products. 相似文献
78.
Tomohiko Mori Fumio Ibuki Setsuro Matsushita Tadao Hata 《Bioscience, biotechnology, and biochemistry》2013,77(9):1229-1235
The RNAs having template activities were extracted from soluble fraction of the cotyledons of soybean seeds. These were consisted of two major components, 9 s and 18 s (High molecular weight RNA, H-RNA). Both components have template activities in the E. coli S-30 system. H-RNA was found in the precipitate fraction when the so-called soluble fraction was centrifuged for 2 hr at 198,000×ɡ. H-RNA increased remarkably in kernels during ripening process and seems to be preserved in the seeds. 相似文献
79.
80.
Hiroyuki Tada Takashi Matsuyama Takashi Nishioka Makoto Hagiwara Yusuke Kiyoura Hidetoshi Shimauchi Kenji Matsushita 《PloS one》2016,11(4)
The cytokine IL-33 is constitutively expressed in epithelial cells and it augments Th2 cytokine-mediated inflammatory responses by regulating innate immune cells. We aimed to determine the role of the periodontal pathogen, Porphyromonas gingivalis, in the enhanced expression of IL-33 in human gingival epithelial cells. We detected IL-33 in inflamed gingival epithelium from patients with chronic periodontitis, and found that P. gingivalis increased IL-33 expression in the cytoplasm of human gingival epithelial cells in vitro. In contrast, lipopolysaccharide, lipopeptide, and fimbriae derived from P. gingivalis did not increase IL-33 expression. Specific inhibitors of P. gingivalis proteases (gingipains) suppressed IL-33 mRNA induction by P. gingivalis and the P. gingivalis gingipain-null mutant KDP136 did not induce IL-33 expression. A small interfering RNA for protease-activated receptor-2 (PAR-2) as well as inhibitors of phospholipase C, p38 and NF-κB inhibited the expression of IL-33 induced by P. gingivalis. These results indicate that the PAR-2/IL-33 axis is promoted by P. gingivalis infection in human gingival epithelial cells through a gingipain-dependent mechanism. 相似文献