全文获取类型
收费全文 | 831篇 |
免费 | 48篇 |
出版年
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 19篇 |
2017年 | 11篇 |
2016年 | 23篇 |
2015年 | 22篇 |
2014年 | 33篇 |
2013年 | 42篇 |
2012年 | 75篇 |
2011年 | 57篇 |
2010年 | 22篇 |
2009年 | 30篇 |
2008年 | 36篇 |
2007年 | 30篇 |
2006年 | 32篇 |
2005年 | 34篇 |
2004年 | 35篇 |
2003年 | 33篇 |
2002年 | 32篇 |
2001年 | 30篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 13篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 15篇 |
1990年 | 15篇 |
1989年 | 8篇 |
1988年 | 11篇 |
1987年 | 5篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 7篇 |
1974年 | 4篇 |
1971年 | 2篇 |
1969年 | 3篇 |
1960年 | 1篇 |
排序方式: 共有879条查询结果,搜索用时 15 毫秒
871.
Con A-Sepharose affinity chromatography was utilized to examine the glycoproteins in phosphosaline extracts of normal and breast tumor tissues and breast patient sera. In extracts of normal breast tissue, normal sera and patient sera, all glycoproteins were eluted from the Con A-Sepharose with a linear gradient of 0.0-0.5 M alpha-methylmannose. Using breast tumor extracts, a glycoprotein peak which could not be eluted as with normal tissue extracts was observed. This tightly-binding peak could be eluted from the Con A-Sepharose with acetate buffer containing 1.0 M KCl. Polyacrylamide electrophoresis of this tightly-binding glycoprotein peak revealed one major glycoprotein and four minor glycoproteins. The major glycoprotein obtained from electrophoresis represented about 60% of the Con A-Sepharose tightly-binding protein and reacted with antiserum to human orosomucoid (alpha 1-acid glycoprotein). All glycoproteins isolated from tumor tissue extracts appeared to represent normal serum constituents as they were retained on an immunoadsorbent containing antibodies to normal serum proteins. The possible significance of the isolated tumor-associated orosomucoid is discussed. 相似文献
872.
Allergen induced histamine release and immunoreactive-leukotriene C4 generation from leukocytes in mite sensitive asthmatic patients 总被引:2,自引:0,他引:2
Leukocytes from mite sensitive asthmatic patient were challenged with the allergen and the supernatant was assayed for histamine and immunoreactive-leukotriene C4 (i-LTC4). The release of histamine was quantitated by an automated fluorometric technique and i-LTC4 was determined using a commercial radioimmunoassay kit. The results of analysis of the supernatant by high speed liquid chromatography, together with observations of modulation of the formation by agents, indicated that i-LTC4 consisted of LTC4 with a little amount of LTD4. i-LTC4 was generated as a result of basophil activation but not derived from the other cells such as monocytes and eosinophils. Allergen induced a concentration-dependent release of histamine and i-LTC4 and the maximal release of histamine and i-LTC4 occurred at the same dose of the allergen. At optimal concentration of the allergen, basophils produced 20.4 +/- 17.9 ng of i-LTC4/10(6)-cells (mean +/- S.D., n = 39) and histamine release was 55.6 +/- 20.1% of total histamine. There was a significant correlation in the capacity of leukocytes to release histamine and i-LTC4 (r = 0.47, p less than 0.01). We found a correlation between maximal histamine release or cell sensitivity, allergen concentration for 50% histamine release, and a ratio of specific IgE to mite to total IgE in the serum, but the amount of i-LTC4 failed to correlate significantly with the ratio. The releasability and the cell sensitivity of asthmatic patients' cells to the allergen for histamine release paralleled the severity to symptoms, but this correlation was not significant in i-LTC4 generation. 相似文献
873.
Hideaki Fujii Ryo Nakajima Junko Akiyama Naoshi Yamamoto Shigeto Hirayama Toru Nemoto Hiroaki Gouda Shuichi Hirono Hiroshi Nagase 《Bioorganic & medicinal chemistry letters》2012,22(24):7697-7701
Previously reported propellane derivative KNT-42 preferred the κ receptor and functioned as a message part in the message-address concept, but its affinity for the κ receptor was not high. To improve affinity, we synthesized five pentacyclic propellane derivatives designed for the purpose of fixing the conformation of KNT-42. The etheno- and ethano-bridged derivatives SYK-347 and SYK-393 exhibited high affinity and selectivity for the κ receptor, whereas the other derivatives did not. These results would be due to the different ranges of movement of the basic nitrogens and less basicity of the nitrogens due to the electron withdrawing effect of the introduced hydroxy or keto group. SYK-347 and SYK-393 preferring the κ receptor were expected to be useful for designing selective ligands for opioid receptor types, especially the κ receptor. 相似文献
874.
Masataka Oda Mie Kurosawa Hirofumi Yamamoto Hisanori Domon Shoji Takenaka Tatsuya Ohsumi Tomoki Maekawa Naoto Yamasaki Yui Furue Yutaka Terao 《Microbiology and immunology》2020,64(7):493-501
Streptococcus mutans is the main pathogen of dental caries and adheres to the tooth surface via soluble and insoluble glucans produced by the bacterial glucosyltransferase enzyme. Thus, the S. mutans glucosyltransferase is an important virulence factor for this cariogenic bacterium. Sulfated vizantin effectively inhibits biofilm formation by S. mutans without affecting its growth. In this study, less S. mutans biofilm formation occurred on hydroxyapatite discs coated with sulfated vizantin than on noncoated discs. Sulfated vizantin showed no cytotoxicity against the human gingival cell line Ca9-22. Sulfated vizantin dose-dependently inhibited the extracellular release of cell-free glucosyltransferase from S. mutans and enhanced the accumulation of cell-associated glucosyltransferase, compared with that observed with untreated bacteria. Sulfated vizantin disrupted the localization balance between cell-associated glucosyltransferase and cell-free glucosyltransferase, resulting in inhibited biofilm maturation. These results indicate that sulfated vizantin can potentially serve as a novel agent for preventing dental caries. 相似文献
875.
876.
Structure of pyocin R. I. Isolation of sheath from pyocin R by alkali treatment and its properties 总被引:5,自引:0,他引:5
C Yui 《Journal of biochemistry》1971,69(1):101-110
877.
878.
T. T. Baba Y. Ohara‐Nemoto T. Miyazaki T. K. Nemoto 《Cell biochemistry and function》2013,31(8):652-659
Simvastatin suppresses myoblast differentiation via inhibition of Rac GTPase, which is involved in the mevalonic acid pathway that produces cholesterol. Statins also inhibit adipogenic differentiation and receptor activator of NFκB ligand (RANKL) expression, possibly through the mevalonic acid pathway, although the involvement of that pathway and effector proteins in these cellular events has not been fully clarified. In the present study, we aimed to elucidate the mechanism of the effects of simvastatin on adipogenic differentiation and calcitriol‐induced RANKL expression in bone marrow stromal ST2 cells. Adipogenesis and mRNA up‐regulation of peroxisome proliferator–activated receptor γ and adipocyte fatty acid–binding protein were induced by troglitazone, and those events were efficiently inhibited by simvastatin. In addition, RANKL expression induced by calcitriol was abrogated by simvastatin in ST2 cells. The inhibitory effects of simvastatin were adequately compensated by the addition of either mevalonic acid or an intermediate of the mevalonic acid pathway, geranylgeranyl pyrophosphate, but not by another intermediate, farnesyl pyrophosphate. These findings suggest that protein geranylgeranylation is related to cellular differentiation in those two directions. Furthermore, inhibitor analysis demonstrated that Rac GTPase is involved in adipogenic differentiation, whereas Rho GTPase was found to be involved in RANKL expression. Taken together, the present findings suggest that geranylgeranylation of Rho family GTPase is involved in both adipogenesis and RANKL expression of stromal cells, while Rac GTPase is involved in adipogenesis and Rho GTPase in RANKL expression. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
879.
Naoto Nemoto Hiroshi Yanagawa Yuzuru Husimi 《Origins of life and evolution of the biosphere》1996,26(3-5):475-476
The recent advances of the evolutionary molecular engineering revealed the effectiveness of bonding strategy for assignment
of the phenotype to its genotype, which non-enveloped viruses such as simple bacteriophages adopt. On the other hand, cellular
organisms adopt another kind of the strategy, namely the compartmentalzation of both genotype and phenotype molecules in a
single compartment enclosed with a cell membrane. The simplest strategy is that adopted by ribozymes in the RNA world. A single
molecule carries both genotype and its phenotype. Based on the definition of “virus”-type and “cell”-type of the assignment
strategy, we propose a virus-early/cell-late model of the history of life. 相似文献