全文获取类型
收费全文 | 77740篇 |
免费 | 7327篇 |
国内免费 | 22篇 |
出版年
2023年 | 281篇 |
2021年 | 1157篇 |
2020年 | 739篇 |
2019年 | 944篇 |
2018年 | 1342篇 |
2017年 | 1206篇 |
2016年 | 1850篇 |
2015年 | 2764篇 |
2014年 | 3137篇 |
2013年 | 3842篇 |
2012年 | 5442篇 |
2011年 | 5425篇 |
2010年 | 3294篇 |
2009年 | 2828篇 |
2008年 | 4552篇 |
2007年 | 4564篇 |
2006年 | 4342篇 |
2005年 | 4059篇 |
2004年 | 3956篇 |
2003年 | 3655篇 |
2002年 | 3576篇 |
2001年 | 1642篇 |
2000年 | 1612篇 |
1999年 | 1242篇 |
1998年 | 1052篇 |
1997年 | 740篇 |
1996年 | 705篇 |
1995年 | 636篇 |
1994年 | 648篇 |
1993年 | 648篇 |
1992年 | 778篇 |
1991年 | 651篇 |
1990年 | 636篇 |
1989年 | 615篇 |
1988年 | 589篇 |
1987年 | 548篇 |
1986年 | 535篇 |
1985年 | 537篇 |
1984年 | 591篇 |
1983年 | 526篇 |
1982年 | 590篇 |
1981年 | 532篇 |
1980年 | 499篇 |
1979年 | 443篇 |
1978年 | 404篇 |
1977年 | 362篇 |
1976年 | 343篇 |
1975年 | 295篇 |
1974年 | 325篇 |
1973年 | 289篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
61.
I. J. Pickering Graham N. George Verena Van Fleet-Stalder Thomas G. Chasteen Roger C. Prince 《Journal of biological inorganic chemistry》1999,4(6):791-794
Received: 2 April 1999 / Accepted: 17 September 1999 相似文献
62.
63.
Cheka Kehelpannala Thusitha Rupasinghe Asher Pasha Eddi Esteban Thomas Hennessy David Bradley Berit Ebert Nicholas J. Provart Ute Roessner 《The Plant journal : for cell and molecular biology》2021,107(1):287-302
Mass spectrometry is the predominant analytical tool used in the field of plant lipidomics. However, there are many challenges associated with the mass spectrometric detection and identification of lipids because of the highly complex nature of plant lipids. Studies into lipid biosynthetic pathways, gene functions in lipid metabolism, lipid changes during plant growth and development, and the holistic examination of the role of plant lipids in environmental stress responses are often hindered. Here, we leveraged a robust pipeline that we previously established to extract and analyze lipid profiles of different tissues and developmental stages from the model plant Arabidopsis thaliana. We analyzed seven tissues at several different developmental stages and identified more than 200 lipids from each tissue analyzed. The data were used to create a web-accessible in silico lipid map that has been integrated into an electronic Fluorescent Pictograph (eFP) browser. This in silico library of Arabidopsis lipids allows the visualization and exploration of the distribution and changes of lipid levels across selected developmental stages. Furthermore, it provides information on the characteristic fragments of lipids and adducts observed in the mass spectrometer and their retention times, which can be used for lipid identification. The Arabidopsis tissue lipid map can be accessed at http://bar.utoronto.ca/efp_arabidopsis_lipid/cgi-bin/efpWeb.cgi . 相似文献
64.
The physical mechanism of calcium pump regulation in the heart. 总被引:4,自引:3,他引:1
The Ca-ATPase in the cardiac sarcoplasmic reticulum membrane is regulated by an amphipathic transmembrane protein, phospholamban. We have used time-resolved phosphorescence anisotropy to detect the microsecond rotational dynamics, and thereby the self-association, of the Ca-ATPase as a function of phospholamban phosphorylation and physiologically relevant calcium levels. The phosphorylation of phospholamban increases the rotational mobility of the Ca-ATPase in the sarcoplasmic reticulum bilayer, due to a decrease in large-scale protein association, with a [Ca2+] dependence parallel to that of enzyme activation. These results support a model in which phospholamban phosphorylation or calcium free the enzyme from a kinetically unfavorable associated state. 相似文献
65.
Cathrine Laustrup M?ller Rasmus Kj?bsted Pablo J. Enriori Thomas Elbenhardt Jensen Cecilia Garcia-Rudaz Sara A. Litwak Kirsten Raun J?rgen Wojtaszewski Birgitte Schjellerup Wulff Michael A. Cowley 《PloS one》2016,11(7)
The melanocortin system includes five G-protein coupled receptors (family A) defined as MC1R-MC5R, which are stimulated by endogenous agonists derived from proopiomelanocortin (POMC). The melanocortin system has been intensely studied for its central actions in body weight and energy expenditure regulation, which are mainly mediated by MC4R. The pituitary gland is the source of various POMC-derived hormones released to the circulation, which raises the possibility that there may be actions of the melanocortins on peripheral energy homeostasis. In this study, we examined the molecular signaling pathway involved in α-MSH-stimulated glucose uptake in differentiated L6 myotubes and mouse muscle explants. In order to examine the involvement of AMPK, we investigate α-MSH stimulation in both wild type and AMPK deficient mice. We found that α-MSH significantly induces phosphorylation of TBC1 domain (TBC1D) family member 1 (S237 and T596), which is independent of upstream PKA and AMPK. We find no evidence to support that α-MSH-stimulated glucose uptake involves TBC1D4 phosphorylation (T642 and S704) or GLUT4 translocation. 相似文献
66.
Risk assessment is part of the risk analysis process as it is used in veterinary medicine to estimate risks related to international trade and food safety. Data from monitoring and surveillance systems (MO&SS) are used throughout the risk assessment process for hazard identification, release assessment, exposure assessment and consequence assessment. As the quality of risk assessments depends to a large extent on the availability and quality of input data, there is a close relationship between MO&SS and risk assessment. In order to improve the quality of risk assessments, MO&SS should be designed according to minimum quality standards. Second, recent scientific developments on state-of-the-art design and analysis of surveys need to be translated into field applications and legislation. Finally, knowledge about the risk assessment process among MO&SS planners and managers should be promoted in order to assure high-quality data. 相似文献
67.
Mingyue Wang Pranab K Mukherjee Jyotsna Chandra Ali Abdul Lattif Thomas S McCormick Mahmoud A Ghannoum 《BMC microbiology》2008,8(1):31
Background
We have previously shown that supernatant from Candida albicans (CA) culture contains a Secretory Interleukin (IL)-12 Inhibitory Factor (CA-SIIF), which inhibits IL-12 production by human monocytes. However, the effect of CA-SIIF on secretion of other cytokines by monocytes is unknown, and detailed characterization of this factor has not been performed. 相似文献68.
69.
70.