全文获取类型
收费全文 | 2385篇 |
免费 | 109篇 |
国内免费 | 3篇 |
出版年
2021年 | 11篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 18篇 |
2016年 | 26篇 |
2015年 | 38篇 |
2014年 | 73篇 |
2013年 | 389篇 |
2012年 | 93篇 |
2011年 | 121篇 |
2010年 | 90篇 |
2009年 | 62篇 |
2008年 | 136篇 |
2007年 | 136篇 |
2006年 | 124篇 |
2005年 | 154篇 |
2004年 | 160篇 |
2003年 | 139篇 |
2002年 | 147篇 |
2001年 | 22篇 |
2000年 | 10篇 |
1999年 | 26篇 |
1998年 | 28篇 |
1997年 | 25篇 |
1996年 | 32篇 |
1995年 | 24篇 |
1994年 | 13篇 |
1993年 | 22篇 |
1992年 | 22篇 |
1991年 | 25篇 |
1990年 | 17篇 |
1989年 | 12篇 |
1988年 | 19篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 14篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1982年 | 24篇 |
1981年 | 30篇 |
1980年 | 22篇 |
1979年 | 10篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1975年 | 11篇 |
1974年 | 11篇 |
1973年 | 6篇 |
1972年 | 5篇 |
排序方式: 共有2497条查询结果,搜索用时 343 毫秒
91.
Keisuke Ueda Chieko Kimura-Sakiyama Tomoki Aihara Masao Miki Toshiaki Arata 《Biophysical journal》2013
To identify the interaction sites of Tm, we measured the rotational motion of a spin-label covalently bound to the side chain of a cysteine that was genetically incorporated into rabbit skeletal muscle tropomyosin (Tm) at positions 13, 36, 146, 160, 174, 190, 209, 230, 271, or 279. Most of the Tm residues were immobilized on actin filaments with myosin-S1 bound to them. The residues in the mid-portion of Tm, namely, 146, 174, 190, 209, and 230, were mobilized when the troponin (Tn) complex bound to the actin-Tm-S1 filaments. The addition of Ca2+ ions partially reversed the Tn-induced mobilization. In contrast, residues at the joint region of Tm, 13, 36, 271, and 279 were unchanged or oppositely changed. All of these changes were detected using a maleimide spin label and less obviously using a methanesulfonate label. These results indicated that Tm was fixed on thin filaments with myosin bound to them, although a small change in the flexibility of the side chains of Tm residues, presumably interfaced with Tn, actin and myosin, was induced by the binding of Tn and Ca2+. These findings suggest that even in the myosin-bound (open) state, Ca2+ may regulate actomyosin contractile properties via Tm. 相似文献
92.
Hiroshi Fukamachi Shinko Kato Makoto Asashima Masao Ichinose Yasuhito Yuasa 《Development, growth & differentiation》2013,55(9):786-791
The importance of epithelial–mesenchymal interaction on the development of gastro‐intestinal (GI) organs has been repeatedly reported, but its molecular mechanism has not been fully understood though several factors including hepatocyte growth factor and endothelin‐3 have been shown to mediate it. Activins have been demonstrated to play important roles in the regulation of organogenesis in vertebrates, but their roles in the regulation of growth and differentiation of GI organs remain to be solved. In the present study, we examined expression of activins in developing rat GI tract, and found that inhibin bA encoding activin A was specifically expressed by GI mesenchymes, while inhibin bB encoding activin B was expressed by both epithelial and mesenchymal components. We then examined the effect of activin A on the growth of fetal rat GI epithelial cells in primary culture. We found that activin A inhibited the growth of forestomach and glandular stomach epithelial cells while it stimulated the growth of colonic epithelial cells. These results suggest that activin A secreted from GI mesenchymes region‐specifically regulates the growth of attaching epithelial cells. We thus conclude that activin A mediates epithelial‐mesenchymal interaction in the developing GI tract. 相似文献
93.
94.
Michiyo Takahara Haruka Sakaue Yukiko Onishi Marifu Yamagishi Yuichiro Kida Masao Sakaguchi 《Biochemical and biophysical research communications》2013,430(2):567-572
Nascent chain release from membrane-bound ribosomes by the termination codon was investigated using a cell-free translation system from rabbit supplemented with rough microsomal membrane vesicles. Chain release was extremely slow when mRNA ended with only the termination codon. Tail extension after the termination codon enhanced the release of the nascent chain. Release reached plateau levels with tail extension of 10 bases. This requirement was observed with all termination codons: TAA, TGA and TAG. Rapid release was also achieved by puromycin even in the absence of the extension. Efficient translation termination cannot be achieved in the presence of only a termination codon on the mRNA. Tail extension might be required for correct positioning of the termination codon in the ribosome and/or efficient recognition by release factors. 相似文献
95.
Masatsugu Toyota Norifumi Ikeda Satoe Sawai‐Toyota Takehide Kato Simon Gilroy Masao Tasaka Miyo Terao Morita 《The Plant journal : for cell and molecular biology》2013,76(4):648-660
The starch‐statolith hypothesis proposes that starch‐filled amyloplasts act as statoliths in plant gravisensing, moving in response to the gravity vector and signaling its direction. However, recent studies suggest that amyloplasts show continuous, complex movements in Arabidopsis shoots, contradicting the idea of a so‐called ‘static’ or ‘settled’ statolith. Here, we show that amyloplast movement underlies shoot gravisensing by using a custom‐designed centrifuge microscope in combination with analysis of gravitropic mutants. The centrifuge microscope revealed that sedimentary movements of amyloplasts under hypergravity conditions are linearly correlated with gravitropic curvature in wild‐type stems. We next analyzed the hypergravity response in the shoot gravitropism 2 (sgr2) mutant, which exhibits neither a shoot gravitropic response nor amyloplast sedimentation at 1 g . sgr2 mutants were able to sense and respond to gravity under 30 g conditions, during which the amyloplasts sedimented. These findings are consistent with amyloplast redistribution resulting from gravity‐driven movements triggering shoot gravisensing. To further support this idea, we examined two additional gravitropic mutants, phosphoglucomutase (pgm) and sgr9, which show abnormal amyloplast distribution and reduced gravitropism at 1 g . We found that the correlation between hypergravity‐induced amyloplast sedimentation and gravitropic curvature of these mutants was identical to that of wild‐type plants. These observations suggest that Arabidopsis shoots have a gravisensing mechanism that linearly converts the number of amyloplasts that settle to the ‘bottom’ of the cell into gravitropic signals. Further, the restoration of the gravitropic response by hypergravity in the gravitropic mutants that we tested indicates that these lines probably have a functional gravisensing mechanism that is not triggered at 1 g . 相似文献
96.
Tsukasa Mizuhara Shinya Oishi Hiroaki Ohno Kazuya Shimura Masao Matsuoka Nobutaka Fujii 《Bioorganic & medicinal chemistry》2013,21(7):2079-2087
To investigate the mechanism of action of the potent antiviral compound PD 404182, three novel photoaffinity probes equipped with a biotin or alkyne indicator were designed and synthesized based on previous structure–activity relationship studies. These probes retained the potent anti-HIV activity of the original pyrimidobenzothiazine derivatives. In photoaffinity labeling studies using HIV-1-infected H9 cells (H9IIIB), eight potential proteins were observed to bind PD 404182. 相似文献
97.
Masao Ohashi Takuji Oyama Endy Widya Putranto Tsuyoshi Waku Hiromi Nobusada Ken Kataoka Kenji Matsuno Masakazu Yashiro Kosuke Morikawa Nam-ho Huh Hiroyuki Miyachi 《Bioorganic & medicinal chemistry》2013,21(8):2319-2332
In the continuing study directed toward the development of peroxisome proliferator-activated receptor gamma (hPPARγ) agonist, we attempted to improve the water solubility of our previously developed hPPARγ-selective agonist 3, which is insufficiently soluble for practical use, by employing two strategies: introducing substituents to reduce its molecular planarity and decreasing its hydrophobicity via replacement of the adamantyl group with a heteroaromatic ring. The first approach proved ineffective, but the second was productive. Here, we report the design and synthesis of a series of α-benzyl phenylpropanoic acid-type hPPARγ partial agonists with improved aqueous solubility. Among them, we selected (R)-7j, which activates hPPARγ to the extent of about 65% of the maximum observed with a full agonist, for further evaluation. The ligand-binding mode and the reason for the partial-agonistic activity are discussed based on X-ray-determined structure of the complex of hPPARγ ligand-binding domain (LBD) and (R)-7j with previously reported ligand-LDB structures. Preliminal apoptotic effect of (R)-7j against human scirrhous gastric cancer cell line OCUM-2MD3 is also described. 相似文献
98.
99.
Norio Shiomi Jiro Yamada Masao Izawa 《Bioscience, biotechnology, and biochemistry》2013,77(11):2233-2244
Nine fructo-oligosaccharides, synthesized in vitro from sucrose by an enzyme preparation from asparagus roots, were isolated and their structures were elucidated to be 1F (1-β-fructofuranosyl)n sucrose [n = 1 (1-kestose), 2 (nystose) and 3], 6G (1-β-fructofuranosyl)n sucrose [n=1 (neokestose), 2 and 3] and 1F (1-β-fructofuranosyl)m-6G (1-β-fructofuranosyl)n sucrose [m=1, n=1; m=2, n =1; and m =1, n=2]. These saccharides are all known to occur naturally in asparagus roots, but 6G (1-β-fructofuranosyl)3 sucrose and 1F (1-β-fructofuranosyl)m-6G-(1-β-fructofuranosyl)n sucrose (m=1, n =1; and m=1, n=2) were the first saccharides enzymatically synthesized in vitro. Also three types of fructosyltransferases were presumed to be involved in the biosynthesis of these oligosaccharides in asparagus roots. 相似文献
100.
Masao Fujimaki Makoto Tajima Teruyo Matsumoto 《Bioscience, biotechnology, and biochemistry》2013,77(10):1228-1231
The free amino acids of potatoes irradiated with the doses of 7,000, 15,000 and 30,000 rad were determined by ion-exchange chromatography.After 15 days storage following irradiation, it was shown that the concentration of asparatic acid, proline and aliphatic amino acids increased with increasing irradiation doses, while that of basic amino acids and glutamic acid especially decreased. However, after 105 days of storage, the similarity of the free amino acid content of irradiated potatoes to that of non-irradiated and non-stored potatoes was observed.On the concentration of protein-bound amino acids, there were no significant differences between non-irradiated and 15,000 rad irradiated potatoes. 相似文献