全文获取类型
收费全文 | 2615篇 |
免费 | 126篇 |
出版年
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 16篇 |
2018年 | 36篇 |
2017年 | 24篇 |
2016年 | 44篇 |
2015年 | 71篇 |
2014年 | 95篇 |
2013年 | 158篇 |
2012年 | 184篇 |
2011年 | 168篇 |
2010年 | 118篇 |
2009年 | 93篇 |
2008年 | 170篇 |
2007年 | 164篇 |
2006年 | 160篇 |
2005年 | 168篇 |
2004年 | 154篇 |
2003年 | 145篇 |
2002年 | 158篇 |
2001年 | 37篇 |
2000年 | 35篇 |
1999年 | 32篇 |
1998年 | 43篇 |
1997年 | 56篇 |
1996年 | 25篇 |
1995年 | 28篇 |
1994年 | 10篇 |
1993年 | 22篇 |
1992年 | 13篇 |
1991年 | 22篇 |
1990年 | 22篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 10篇 |
1986年 | 14篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 11篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 16篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 5篇 |
1976年 | 13篇 |
1975年 | 9篇 |
1973年 | 5篇 |
1968年 | 4篇 |
排序方式: 共有2741条查询结果,搜索用时 15 毫秒
81.
Akihiko Nishikimi Mutsuko Kukimoto-Niino Shigeyuki Yokoyama Yoshinori Fukui 《Experimental cell research》2013
DOCK proteins constitute a family of evolutionarily conserved guanine nucleotide exchange factors (GEFs) for Rho family of GTPases. Although DOCK family proteins do not contain the Dbl homology domain typically found in GEFs, they mediate the GTP–GDP exchange reaction through DHR-2 domain. Accumulating evidence indicates that the DOCK proteins act as major GEFs in varied biological settings. For example, DOCK2, which is predominantly expressed in hematopoietic cells, regulates migration and activation of leukocytes through Rac activation. On the other hand, it was recently reported that mutations of DOCK8, another member of the DOCK family proteins, cause a combined immunodeficiency syndrome in humans. This article reviews the structure, functions and signaling of DOCK2 and DOCK8, especially focusing on their roles in immune responses. 相似文献
82.
Kazuyuki Nakamura Hirofumi Kodera Tenpei Akita Masaaki Shiina Mitsuhiro Kato Hideki Hoshino Hiroshi Terashima Hitoshi Osaka Shinichi Nakamura Jun Tohyama Tatsuro Kumada Tomonori Furukawa Satomi Iwata Takashi Shiihara Masaya Kubota Satoko Miyatake Eriko Koshimizu Kiyomi Nishiyama Mitsuko Nakashima Yoshinori Tsurusaki Noriko Miyake Kiyoshi Hayasaka Kazuhiro Ogata Atsuo Fukuda Naomichi Matsumoto Hirotomo Saitsu 《American journal of human genetics》2013
83.
Yoshinori Takino Hiroshi Imagawa Hiroyuki Yoshida 《Bioscience, biotechnology, and biochemistry》2013,77(10):699-704
Yellow needle crystals, C21H20O13?H2O have been isolated from tea leaves. The crystals yield myricetin (hexaacetate, m.p. 211~212°C), glucose and galactose on hydrolysis. As analytical data indicate the molecular ratio of myricetin to the sugars to be 1:1 and the only bonding position of the sugars to be position 3 of the aglycone, the crystals are concluded to consist of two kinds of glycosides, namely myricetin-3-glucoside and myricetin-3-galactoside. 相似文献
84.
Yataro Obata Haruo Tanaka Yoshinori Ishikawa 《Bioscience, biotechnology, and biochemistry》2013,77(2):104-110
The recent findings1~3) that prenylmercaptan (3-methyl-2-butene-1-thiol) is the major component of the sunlight flavor of beer has led us to investigate the pathway of its evolution. S-Prenyl-l-cysteine, S-(3-methyl-2-butenyl)-l-cysteine, was synthesized according to the general outline of A. Stoll et al.4) from l-cyteine and prenylbromide, since it was considered as one of the precursors of the sunlight flavor of beer. S-Prenyl-l-cysteine was a colorless and odorless crystal, but this compound generated prenylmercaptan when the aqueous solution was exposed to sunlight. The addition of a small amount of riboflavin to the solution as a photosensitizer increased the mercaptan evolution. Prenylmercaptan formed by sunlight was isolated as its 2,4-dinitrophenyl derivative and identified by the comparison of melting point, chromatographic behavior and infrared spectrum with an authentic sample and by its elemental analysis. 相似文献
85.
Keishi Shimokawa Yoshinori Ueda Zenzaburo Kasai 《Bioscience, biotechnology, and biochemistry》2013,77(11):2021-2024
ABSTRACTJapanese apricot, Prunus mume Sieb. et Zucc., biosynthesizes the l-phenylalanine-derived cyanogenic glucosides prunasin and amygdalin. Prunasin has biological properties such as anti-inflammation, but plant extraction and chemical synthesis are impractical. In this study, we identified and characterized UGT85A47 from Japanese apricot. Further, UGT85A47 was utilized for prunasin microbial production. Full-length cDNA encoding UGT85A47 was isolated from Japanese apricot after 5?- and 3?-RACE. Recombinant UGT85A47 stoichiometrically catalyzed UDP-glucose consumption and synthesis of prunasin and UDP from mandelonitrile. Escherichia coli C41(DE3) cells expressing UGT85A47 produced prunasin (0.64 g/L) from racemic mandelonitrile and glucose. In addition, co-expression of genes encoding UDP-glucose biosynthetic enzymes (phosphoglucomutase and UTP-glucose 1-phosphate uridiltransferase) and polyphosphate kinase clearly improved prunasin production up to 2.3 g/L. These results showed that our whole-cell biocatalytic system is significantly more efficient than the existing prunasin production systems, such as chemical synthesis. 相似文献
86.
87.
Junya Mizutani Yataro Obata Yoshinori Ishikawa 《Bioscience, biotechnology, and biochemistry》2013,77(4):382-385
Cysteine-aldehyde compounds were prepared by the reactions of l-cysteine with formaldehyde, acetaldehyde, n-butyraldehyde, benzaldehyde and furfural in 50% ethanol solutions. Hydrogen sulfide and ammonia liberated from cysteine-aldehyde compounds in heated aqueous solutions (oil bath : 120°C) were determined. Although thiazolidine derivatives were stable generally in boiling aqueous solution, l-cysteine-furfural compound was unstable and a large amount of hydrogen sulfide compared with other compounds was released. 相似文献
88.
By using the multiple ascent technique, the authors have resolved the first several oligosaccharides of the product of initial stage of potato phosphorylase action in both the absence and the presence of beet-saponin with maltotriose as primer. The resolved chromatogram was sprayed with a mixture of G-1-P and phosphorylase, followed by spraying with iodine solution to locate the spots in which starch synthesis occurred.Multi-chain mechanism of amylose formation from maltotriose and the suppression of lengthening of amylose chain by beet-saponin in the lag stage of enzyme action could be shown on paper chromatogram. No saccharides other than amylose series were recognized in the case of phosphorylase inhibition by beet-saponin. 相似文献
89.
Saburo Tamura Shimpei Kuyama Yoshinori Kodaira Shizuo Higashikawa 《Bioscience, biotechnology, and biochemistry》2013,77(2):137-138
The viability of freeze-dried Lactobacillus bulgaricus B-1 was affected by rehydration temperature, and maximum recovery of the viable cells was obtained when they were rehydrated at 20 to 25°C. Cellular ribonucleotides leaked out from the freeze-dried cells during rehydration, but there was no correlation between the viability of cells and the amount of leaked substances. Rehydration of the freeze-dried cells in the presence of RNase caused marked loss of viability. These results suggest that the cell surface was damaged by freeze-drying and its selective permeability was lost to some extent. 相似文献
90.
Ryotaro Myokei Akira Sakurai Ching-Fun Chang Yoshinori Kodaira Nobutaka Takahashi Saburo Tamura 《Bioscience, biotechnology, and biochemistry》2013,77(10):1491-1500
A new insecticidal substance named aspochracin was isolated from the culture filtrate of Aspergillus ochraceus, a pathogenic fungus causing muscardine on insects. The compound was found to be a novel cyclotripeptide, composed of N-methyl-l-alanine, N-methyl-l-valine and l-ornithine, containing an octatrienoic acid side chain. Isolation procedure, structural elucidation and biological activities are described in detail.Hexahydroaspochracin (II) derived on hydrogenation of aspochracin (I), an insecticidal metabolite of Aspergillus ochraceus, was synthesized by cyclization of N-methyl-l-valyl-N- methyl-l-alanyl-α-caprylyl-l-ornithine (XIV). In addition to II, isohexahydroaspochracin (XV) was isolated from the reaction mixture. 相似文献