全文获取类型
收费全文 | 2696篇 |
免费 | 157篇 |
国内免费 | 1篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 24篇 |
2020年 | 13篇 |
2019年 | 21篇 |
2018年 | 26篇 |
2017年 | 41篇 |
2016年 | 55篇 |
2015年 | 84篇 |
2014年 | 97篇 |
2013年 | 255篇 |
2012年 | 151篇 |
2011年 | 135篇 |
2010年 | 113篇 |
2009年 | 97篇 |
2008年 | 169篇 |
2007年 | 183篇 |
2006年 | 203篇 |
2005年 | 180篇 |
2004年 | 194篇 |
2003年 | 161篇 |
2002年 | 137篇 |
2001年 | 23篇 |
2000年 | 24篇 |
1999年 | 39篇 |
1998年 | 29篇 |
1997年 | 27篇 |
1996年 | 27篇 |
1995年 | 28篇 |
1994年 | 30篇 |
1993年 | 25篇 |
1992年 | 28篇 |
1991年 | 18篇 |
1990年 | 21篇 |
1989年 | 11篇 |
1988年 | 22篇 |
1987年 | 16篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 16篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1973年 | 4篇 |
排序方式: 共有2854条查询结果,搜索用时 15 毫秒
71.
Akiharu Kubo Aiko Shiohama Takashi Sasaki Kazuhiko Nakabayashi Hiroshi Kawasaki Toru Atsugi Showbu Sato Atsushi Shimizu Shuji Mikami Hideaki Tanizaki Masaki Uchiyama Tatsuo Maeda Taisuke Ito Jun-ichi Sakabe Toshio Heike Torayuki Okuyama Rika Kosaki Kenjiro Kosaki Jun Kudoh Kenichiro Hata Akihiro Umezawa Yoshiki Tokura Akira Ishiko Hironori Niizeki Kenji Kabashima Yoshihiko Mitsuhashi Masayuki Amagai 《American journal of human genetics》2013,93(5):945-956
“Nagashima-type” palmoplantar keratosis (NPPK) is an autosomal recessive nonsyndromic diffuse palmoplantar keratosis characterized by well-demarcated diffuse hyperkeratosis with redness, expanding on to the dorsal surfaces of the palms and feet and the Achilles tendon area. Hyperkeratosis in NPPK is mild and nonprogressive, differentiating NPPK clinically from Mal de Meleda. We performed whole-exome and/or Sanger sequencing analyses of 13 unrelated NPPK individuals and identified biallelic putative loss-of-function mutations in SERPINB7, which encodes a cytoplasmic member of the serine protease inhibitor superfamily. We identified a major causative mutation of c.796C>T (p.Arg266∗) as a founder mutation in Japanese and Chinese populations. SERPINB7 was specifically present in the cytoplasm of the stratum granulosum and the stratum corneum (SC) of the epidermis. All of the identified mutants are predicted to cause premature termination upstream of the reactive site, which inhibits the proteases, suggesting a complete loss of the protease inhibitory activity of SERPINB7 in NPPK skin. On exposure of NPPK lesional skin to water, we observed a whitish spongy change in the SC, suggesting enhanced water permeation into the SC due to overactivation of proteases and a resultant loss of integrity of the SC structure. These findings provide an important framework for developing pathogenesis-based therapies for NPPK. 相似文献
72.
Hideo Ochiai Hiroshi Eguchi Shunsuke Noguchi Yutaro Hayashi Hideaki Nishino Masaru Kawamura Chau H. Wu 《Journal of molecular recognition : JMR》2013,26(1):32-37
Glutathione S‐transferase (GST) was found to complex with the Na+,K+‐ATPase as shown by binding assay using quartz crystal microbalance. The complexation was obstructed by the addition of antiserum to the α‐subunit of the Na+,K+‐ATPase, suggesting the specificity of complexation between GST and the Na+,K+‐ATPase. Co‐immunoprecipitation experiments, using the anti‐α‐subunit antiserum to precipitate the GST‐Na+,K+‐ATPase complex and then using antibodies specific to an isoform of GST to identify the co‐precipitated proteins, revealed that GSTπ was complexed with the Na+,K+‐ATPase. GST stimulated the Na+,K+‐ATPase activity up to 1.4‐fold. The level of stimulation exhibited a saturable dose–response relationship with the amount of GST added, although the level of stimulation varied depending on the content of GSTπ in the lots of GST received from supplier. The stimulation was also obtained when recombinant GSTπ was used, confirming the results. When GST was treated with reduced glutathione, GST activity was greatly stimulated, whereas the level of stimulation of the Na+,K+‐ATPase activity was similar to that when untreated GST was added. When GST was treated with H2O2, GST activity was greatly diminished while the stimulation of the Na+,K+‐ATPase activity was preserved. The results suggest that GSTπ complexes with the Na+,K+‐ATPase and stimulates the latter independent of its GST activity. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
73.
Yoshiki Tani Byung Dae Yoon Hideaki Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(8):2385-2391
An obligate methanol-utilizing bacterium, Methylomonas sp. YK 1, was isolated and used as a cytochrome c producer. The strain was mutagenized so as to be resistant to metabolic inhibitors related to the function of cytochrome c. The strain, YK 56, which was derived as a KCN-resistant mutant contained 3 times the cellular level of cytochrome c compared to the parent strain. Optimization of the culture conditions for the mutant to enhance the cytochrome c productivity was performed. Peptone, succinate, l-malate or FeSO4 · 7H2O increased the productivity when added to the culture medium. Under the optimal culture conditions, strain YK 56 produced about 60 mg cytochrome c per liter when methanol and peptone were fed to the medium during the cultivation. 相似文献
74.
Hajime Yoshida Keizo Hanada Hisakazu Ohsawa Hidehiko Kumagai Hideaki Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(4):1035-1042
Biosynthetic threonine deaminase was purified to an apparent homogeneous state from the cell extract of Proteus morganii, with an overall yield of 7.5%. The enzyme had a s020,w of 10.0 S, and the molecular weight was calculated to be approximately, 228,000. The molecular weight of a subunit of the enzyme was estimated to be 58,000 by sodium dodecyl sulfate gel electrophoresis. The enzyme seemed to have a tetrameric structure consisting of identical subunits. The enzyme had a marked yellow color with an absorption maximum at 415 nm and contained 2 mol of pyridoxal 5′-phosphate per mol. The threonine deaminase catalyzed the deamination of l-threonine, l-serine, l-cysteine and β-chloro-l-alanine. Km values for l-threonine and l-serine were 3.2 and 7.1 mm, respectively. The enzyme was not activated by AMP, ADP and ATP, but was inhibited by l-isoleucine. The Ki for l-isoleucine was 1.17 mm, and the inhibition was not recovered by l-valine. Treatment with mercuric chloride effectively protected the enzyme from inhibition by l-isoleucine. 相似文献
75.
Akitami Ichihara Hideaki Oikawa Masaaki Hashimoto Sadao Sakamura Tokuko Haraguchi Hiroshi Nagano 《Bioscience, biotechnology, and biochemistry》2013,77(12):2965-2967
For rough quantitative analysis of genetically modified maize contents, rapid methods for measurement of the copy numbers of the cauliflower mosaic virus 35S promoter region (P35S) and MON810 construct-specific gene (MON810) using a combination of a capillary-type real-time PCR system with a plasmid DNA were established. To reduce the characteristic differences between the plasmid DNA and genomic DNA, we showed that pretreatment of the extracted genomic DNA by a combination of sonication and restriction endonuclease digestion before measurement is effective. The accuracy and reproducibility of this method for MON810 content (%) at a level of 5.0% MON810 mixed samples were within a range from 4.26 to 5.11% in the P35S copy number quantification. These methods should prove to be a useful tool to roughly quantify GM maize content. 相似文献
76.
77.
Hideaki Yamada Hidehiko Kumagai Takatoshi Nagate Hajime Yoshida 《Bioscience, biotechnology, and biochemistry》2013,77(9):1340-1345
Threonine aldolase was found to be formed in various strains of bacteria and yeasts when they were grown in media containing l-threonine as a sole source of carbon. As the other sources of carbon, d, l-allothreonine, l-serine and glycine were effective but glucose and sucrose were inert for the formation of the enzyme.The maximal formation of the enzyme was observed in the initial of stationary phase of growth and, thereafter, the enzyme disappeared with the consumption of l-threonine. It seems that the enzyme is adaptive in nature and that it is responsible for the growth in threonine as the carbon source. 相似文献
78.
Nobuhiro Mori Bunsei Kawakami Yoshiki Tani Hideaki Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(6):1383-1389
Dimethylglycine oxidase was purified to homogeneity from the cell extract of Cylindrocarpon didymum M–1, aerobically grown in medium containing betaine as the carbon source. The molecular weight of the enzyme was estimated to be 170,000 by the gel filtration method and 180,000 by the sedimentation velocity method. The enzyme exhibited an absorption spectrum characteristic of a flavoprotein with absorption maxima at 277, 345 and 450 nm. The enzyme consisted of two identical subunits with a molecular weight of 82,000, and contained two mol of FAD per mol of enzyme. The flavin was shown to be covalently bound to the protein. The enzyme was inactivated by Ag+, Hg2+, Zn2+ and iodoacetate. The enzyme oxidized dimethylglycine but was inert toward choline, betaine, sarcosine and alkylamines. Km and Vmax values for dimethylglycine were 9.1 mm and 1.22 μmol/min/mg, respectively. The enzyme catalyzed the following reaction: Dimethylglycine+O2+H2O → sarcosine+formaldehyde+H2O2. 相似文献
79.
Sakayu Shimizu Hazimu Morioka Keiko Inoue Koji Yasui Yoshiki Tani Hideaki Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(11):2659-2665
The distribution of acyl-CoA synthetase was investigated among microorganisms. High enzyme activity was found in some strains in genera of Pseudomonas, Fusarium, Gibberella and Cylindrocarpon, and in many strains of basidiomycetes. There were two groups in respect to enzyme formation. The enzyme activities of Escherichia, Klebsiella, Enterobacter, Citrobacter and Serratia were detected only when they were grown with fatty acids as the carbon source. On the other hand, the activities of many fungal strains and pseudomonads were easily detected regardless of the carbon source for growth.Gel filtration on Sephadex G-200 showed that the enzymes of Escherichia coli and Gibberella fujikuroi were mostly present around the void volume of the column and retarded by the gel after treatment with Triton X-100. Pseudomonas aeruginosa produced two kinds of enzymes, one was eluted around the void volume of the column and the other retarded by the gel. This elution pattern did not change upon treatment with Triton X-100. Some catalytic properties of acyl-CoA synthetases from P. aeruginosa and G. fujikuroi were also described. 相似文献
80.
Fusako Kawai Kensei Maezato Hideaki Yamada Koichi Ogata 《Bioscience, biotechnology, and biochemistry》2013,77(9):1675-1679
The formation of D-pantothenic acid-α-glucoside (PaA-α-G) was found from D-pantothenic acid (PaA) and maltose in incubation mixtures of microorganisms, especially Saccharomyces yeasts and Sporobolomyces coralliformis IFO 1032. The reaction conditions were investigated for formation of PaA-α-G by resting cells of Spor. coralliformis. The formation of the compound increased with PaA concentration (3~20 mg/ml). The yield was maximum at 5~10 mg/ml of PaA. Cetyl trimethyl ammonium bromide (0.1 %) promoted the formation of PaA-α-G. Sucrose was the optimal α-glucosyl donor. When 30 mg/ml of sucrose was fed to the reaction mixture (initial sucrose, 100 mg/ml; and PaA, 10 mg/ml) at 12-hr intervals, 5.74 mg/ml (3.30 mg/ml as PaA) of PaA-α-G was formed in 48-hr incubation at 28°C with shaking. PaA-α-G was also formed by yeast α-glucosidase, mold maltase and the cell-free extract of Spor. coralliformis. The compound showed approximately 9~10% and 0.1~0.3% (molar ratio) of activity of PaA for Saccharomyces carlsbergensis ATCC 9080 and Lactobacillus plantarum ATCC 8014, respectively. The compound had the same microbiological activity as authentic 4′-O-(α-D-glucopyranosyl)-D-pantothenic acid. 相似文献