全文获取类型
收费全文 | 3076篇 |
免费 | 206篇 |
国内免费 | 1篇 |
出版年
2022年 | 24篇 |
2021年 | 50篇 |
2020年 | 23篇 |
2019年 | 49篇 |
2018年 | 45篇 |
2017年 | 39篇 |
2016年 | 53篇 |
2015年 | 87篇 |
2014年 | 100篇 |
2013年 | 208篇 |
2012年 | 156篇 |
2011年 | 168篇 |
2010年 | 98篇 |
2009年 | 90篇 |
2008年 | 177篇 |
2007年 | 149篇 |
2006年 | 157篇 |
2005年 | 153篇 |
2004年 | 144篇 |
2003年 | 146篇 |
2002年 | 127篇 |
2001年 | 108篇 |
2000年 | 118篇 |
1999年 | 80篇 |
1998年 | 54篇 |
1997年 | 33篇 |
1996年 | 30篇 |
1995年 | 17篇 |
1994年 | 18篇 |
1993年 | 33篇 |
1992年 | 62篇 |
1991年 | 37篇 |
1990年 | 43篇 |
1989年 | 37篇 |
1988年 | 29篇 |
1987年 | 22篇 |
1986年 | 24篇 |
1985年 | 28篇 |
1984年 | 23篇 |
1983年 | 21篇 |
1982年 | 24篇 |
1981年 | 15篇 |
1980年 | 13篇 |
1979年 | 20篇 |
1978年 | 21篇 |
1977年 | 19篇 |
1974年 | 12篇 |
1971年 | 12篇 |
1970年 | 13篇 |
1969年 | 11篇 |
排序方式: 共有3283条查询结果,搜索用时 15 毫秒
121.
Takao Murata 《Bioscience, biotechnology, and biochemistry》2013,77(2):297-299
The molecular weight of the yeast tannase [E.C. 3.1.1.20, tannin acyl-hydrolase] of Candida sp. was determined to be 250,000 by gel filtration on Sephadex G–200. The enzyme was dissociable into two identical subunits with molecular weight of 120,000 on SDS-polyacrylamide gel electrophoresis. The amino acid analysis revealed that the enzyme consisted of 786 amino acid residues per protein molecule. The polypeptide moiety of the enzyme was 38 % by the Lowry-Folin reaction and 35% by the amino acid analysis. The enzyme contained 62% neutral sugars, which were identified as mannose and galactose on cellulose thin-layer chromatogram and 2.2 % hexosamines. 相似文献
122.
Kohei Oda Takanori Nakazima Takao Terashita Ken-ichiro Suzuki Sawao Murao 《Bioscience, biotechnology, and biochemistry》2013,77(11):3073-3080
A S-PI(Pepstatin Ac)-insensitive carboxyl proteinase was found in culture filtrate of a Xanthomonas sp. bacterium. The carboxyl proteinase was highly purified and about 100 mg of the enzyme was obtained from 601 of culture filtrate, with a recovery of 25%. The optimum condition for the action of the purified enzyme toward casein was approx. pH 2.7 and its activity was not inhibited by any of such carboxyl proteinase inhibitors as Pepstatin, S-PI, and DAN but EPNP inhibited it. Such behavior of the enzyme against inhibitors resembles that of Pseudomonas sp. carboxyl proteinase, the first found from a bacterium. Some differences were observed, however, in their properties such as optimum pH, isoelectric point, and amino acid composition. 相似文献
123.
Akira Murata Mamoru Odaka Syoichi Mukuno 《Bioscience, biotechnology, and biochemistry》2013,77(2):477-478
Some physicochemical properties and substrate specificity of acid protease B isolated from Scytalidium lignicolum were investigated.The molecular weight determined by the sedimentation equilibrium and sedimentation velocity method was 21,000 and 19,000~20,000, respectively. The isoelectric point was determined as 3.0 using the Tiselius electrophoresis apparatus, 3.2 by isoelectric focusing, respectively.The enzyme did not contain histidine and was composed of 188 amino acid residues. Substrate specificity against various synthetic peptides was different from those of the acid proteases which were inactivated by S–PI and DAN. 相似文献
124.
Toshizo Kimura Makiko Nishiyama Kiku Murata 《Bioscience, biotechnology, and biochemistry》2013,77(7):1033-1038
In an attempt to study on metabolic changes in rats fed on an amino acid diet devoid of one branched chain amino acid and of niacin, rats were force-fed a leucine-free, isoleucine-free, valine-free or complete amino acid diet for 3 or 4 days and killed 3 hr after the feeding on day 4 or 5 to observe the body weight changes, the urinary nitrogen and N1-methylnicotinamide (MNA), and liver tryptophanpyrrolase (TPase) and tyrosine-α-keto-glutarate transaminase (TKase) activities.The excretion of the urinary nitrogen and MNA, TPase and TKase activities, and fat content of livers of rats force-fed these amino acid deficient diets were higher than those fed the complete amino acid diet. It was further confirmed in the present study that changes in TPase activity of rats given diets devoid of one essential amino acid were in the same direction with changes in urinary MNA which was observed in the previous studies on rats given threonine-free, tryptophan-free, methionine-free, lysine-free and complete amino acid diets. However, such metabolic changes in rats fed the leucine-free diet were not so remarkable, compared with those of rats fed the other amino acid deficient diets. 相似文献
125.
Kousaku Murata Tomofumi Uchida Jyoji Kato Ichiro Chibata 《Bioscience, biotechnology, and biochemistry》2013,77(5):1165-1172
The enzyme utilizing metaphosphate for nicotinamide adenine dinucleotide phosphorylation was purified 500-fold from B. ammoniagenes and its properties were studied. The isolated enzyme appeared homogeneous on disc gel electrophoresis; its molecular weight was determined to be 9.0 × 104 by gel filtration. This enzyme specifically phosphorylated nicotinamide adenine dinucleotide at the optimum pH at 6.0. Of phosphoryl donors tested, metaphosphate was most effective for the reaction, and adenosine-5′-triphosphate was less effective. The activity was inhibited by adenosine-5′-monophosphate, adenosine-5′-diphosphate or reduced pyridine nucleotides. The enzyme did not exhibit catalytic activity in the absence of a divalent cation. We concluded that the enzyme phosphorylating nicotinamide adenine dinucleotide in the presence of metaphosphate is distinct from adenosine-5′-triphosphate-dependent nicotinamide adenine dinucleotide kinase, and tentatively designated it metaphosphate-dependent nicotinamide adenine dinucleotide kinase. 相似文献
126.
Tsutomu Nagaya Noriko Okamoto Kousaku Murata Akira Kimura 《Bioscience, biotechnology, and biochemistry》2013,77(9):2393-2394
The effects of the injection of a large amount of N1 -methylnicotinamide (MNA) (500 mg per kg body weight) on the ratio of N1 -methyl-4-pyridone-3-carboxamide (4-py) to N1 -methyl-2-pyridone-5- carboxamide (2-py) excretion, and the activities of 2-py and 4-py forming MNA oxidases were investigated in rats. The injected MN A was excreted very rapidly into the urine; 46 % of the dose was excreted from 0~3hr post-injection, 15% from 3~6hr, 6% from 6~9hr and 1.5% from 9~ 12hr. The ratio of 4-py to 2-py also decreased rapidly; the ratio being about 0.6, 0.4, 0.4 and 0.6 from 0~3hr, 3~6hr, 6~9hr and 9~ 12hr post-injection, respectively. This ratio then recovered rapidly; being about 2, 5.5, 8.5 and 9.7 from 12~24 hr, 24 ~48 hr, 48~72 hr and 72 ~96 hr post-injection, respectively. The normal range of 4-py to 2-py excretion ratio is 8~14. So, this ratio returned to a normal level by day 3 post-injection. The rats were killed 5 hr after the MNA injection. At this time (the lowest ratio was observed around this time), the activities of 2-py and 4-py forming MNA oxidases in the injected group were 59 % and 11 % of the normal levels, respectively. Therefore, it was found that the decreased ratio of 4-py to 2-py excretion with the MNA injection was mainly due to the higher inhibition of the 4-py forming MNA oxidase than of the 2-py forming MNA oxidase by the MNA injection. 相似文献
127.
Akio Kobayashi Kyohei Yamashita Kohei Ohshima Izuru Yamamoto 《Bioscience, biotechnology, and biochemistry》2013,77(12):1961-1965
Allethrin-(E)-Ol (IV), allethrin-(E)-al (V) and allethrin-(E)-acid (VI), the metabolites of allethrin (III) in the insect body, were synthesized. Their low toxicities to houseflies seem to support the hypothesis that they are products of the detoxication process of allethrin. 相似文献
128.
Kousaku Murata Keiko Tani Jyoji Kato Ichiro Chibata 《Bioscience, biotechnology, and biochemistry》2013,77(9):2131-2132
Certain edible large jellyfishes belonging to the order Rhizostomeae are consumed in large quantities in China and Japan. The exumbrella part of the edible jellyfish Stomolophus nomurai was cut and soaked in dilute hydrochloric acid solution (pH 3.0) for 12 h, and heated at 121 °C for 20 min. The immunostimulation effects of the jellyfish extract were examined. The jellyfish extract enhanced IgM production of human hybridoma HB4C5 cells 34-fold. IgM and IgG production of human peripheral blood lymphocytes (PBL) were also accelerated, 2.8- and 1.4-fold respectively. Moreover, production of interferon (IFN)-γ and tumor necrosis factor (TNF)-α by human PBL was stimulated 100- and 17-fold respectively. Collagenase treatment inactivated the immunostimulation activity of the jellyfish extract. In addition, purified collagen from bovine Achilles’ tendon accelerated IgM production of hybridoma cells. These facts mean that collagen has an immunostimulation effect, and that the active substance in jellyfish extract is collagen. 相似文献
129.
Makoto Shimosaka Yasuki Fukuda Kousaku Murata Akira Kimura 《Bioscience, biotechnology, and biochemistry》2013,77(5):1303-1310
An adenosine-sensitive mutant was isolated from Escherichia coli K12 derivative strain C600. This mutant (designated as PS100) grew slower than parental strain C600in a minimal medium, and its growth was completely inhibited by addition of all kinds of purine bases, nucleosides and nucleotides tested. On the other hand, this growth inhibitory effect of purine derivatives was reversed by co-addition of uridine to the medium. Other pyrimidine derivatives such as uracil, UMP,cytosine, cytidine, CMP and thymidine were also effective for this reversal. The mutant strain, PS100, showed a lower level (7%) of activity for orotate phosphoribosyltransferase than strain C600 did, and accumulated orotic acid in the growth medium. Lysogenization of strain PS100 with λ transducing phage containing the gene for orotate phosphoribosyltransferase (pyrE) resulted in restoration of the activity for orotate phosphoribosyltransferase and removal of growth inhibition by purine derivatives. 相似文献
130.