全文获取类型
收费全文 | 1474篇 |
免费 | 128篇 |
出版年
2023年 | 4篇 |
2022年 | 20篇 |
2021年 | 41篇 |
2020年 | 15篇 |
2019年 | 27篇 |
2018年 | 34篇 |
2017年 | 30篇 |
2016年 | 50篇 |
2015年 | 56篇 |
2014年 | 63篇 |
2013年 | 91篇 |
2012年 | 143篇 |
2011年 | 116篇 |
2010年 | 87篇 |
2009年 | 75篇 |
2008年 | 90篇 |
2007年 | 111篇 |
2006年 | 82篇 |
2005年 | 94篇 |
2004年 | 95篇 |
2003年 | 63篇 |
2002年 | 68篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 16篇 |
1997年 | 14篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1968年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1958年 | 3篇 |
1957年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1602条查询结果,搜索用时 31 毫秒
151.
Shelud'ko NS Matusovskaya GG Permyakova TV Matusovsky OS 《Archives of biochemistry and biophysics》2004,432(2):269-277
Twitchin belongs to the titin-like giant proteins family, it is co-localized with thick filaments in molluscan catch muscles and regulates the catch state depending on its level of phosphorylation. The mechanism by which twitchin controls the catch state remains to be established. We report for the first time the ability of twitchin to interact with F-actin. The interaction is observed at low and physiological ionic strengths, irrespective of the presence or absence of Ca(2+). It was demonstrated by viscosity and turbidity measurements, low- and high-speed co-sedimentation, and with the light-scattering particle size analysis revealing the specific twitchin-actin particles. The twitchin-actin interaction is regulated by twitchin phosphorylation: in vitro phosphorylated twitchin does not interact with F-actin. We speculate that the catch muscle twitchin might provide a mechanical link between thin and thick filaments, which contributes to catch force maintenance. 相似文献
152.
Lusetti SL Voloshin ON Inman RB Camerini-Otero RD Cox MM 《The Journal of biological chemistry》2004,279(29):30037-30046
When DinI is present at concentrations that are stoichiometric with those of RecA or somewhat greater, DinI has a substantial stabilizing effect on RecA filaments bound to DNA. Exchange of RecA between free and bound forms was almost entirely suppressed, and highly stable filaments were documented with several different experimental methods. DinI-mediated stabilization did not affect RecA-mediated ATP hydrolysis and LexA co-protease activities. Initiation of DNA strand exchange was affected in a DNA structure-dependent manner, whereas ongoing strand exchange was not affected. Destabilization of RecA filaments occurred as reported in earlier work but only when DinI protein was present at very high concentrations, generally superstoichiometric, relative to the RecA protein concentration. DinI did not facilitate RecA filament formation but stabilized the filaments only after they were formed. The interaction between the RecA protein and DinI was modulated by the C terminus of RecA. We discuss these results in the context of a new hypothesis for the role of DinI in the regulation of recombination and the SOS response. 相似文献
153.
The primary pathogenic event of sickle cell anemia is the polymerization of the mutant hemoglobin (Hb) S within the red blood cells, occurring when HbS is in deoxy state in the venous circulation. Polymerization is known to start with nucleation of individual polymer fibers, followed by growth and branching via secondary nucleation, yet the mechanisms of nucleation of the primary fibers have never been subjected to dedicated tests. We implement a technique for direct determination of rates and induction times of primary nucleation of HbS fibers, based on detection of emerging HbS polymers using optical differential interference contrast microscopy after laser photolysis of CO-HbS. We show that: (i). nucleation throughout these determinations occurs homogeneously and not on foreign substrates; (ii). individual nucleation events are independent of each other; (iii). the nucleation rates are of the order of 10(6)-10(8)cm(-3)s(-1); (iv). nucleation induction times agree with an a priori prediction based on Zeldovich's theory; (v). in the probed parameter space, the nucleus contains 11 or 12 molecules. The nucleation rate values are comparable to those leading to erythrocyte sickling in vivo and suggest that the mechanisms deduced from in vitro experiments might provide physiologically relevant insights. While the statistics and dynamics of nucleation suggest mechanisms akin to those for small-molecule and protein crystals, the nucleation rate values are nine to ten orders of magnitude higher than those known for protein crystals. These high values cannot be rationalized within the current understanding of the nucleation processes. 相似文献
154.
Behar DM Metspalu E Kivisild T Achilli A Hadid Y Tzur S Pereira L Amorim A Quintana-Murci L Majamaa K Herrnstadt C Howell N Balanovsky O Kutuev I Pshenichnov A Gurwitz D Bonne-Tamir B Torroni A Villems R Skorecki K 《American journal of human genetics》2006,78(3):487-497
Both the extent and location of the maternal ancestral deme from which the Ashkenazi Jewry arose remain obscure. Here, using complete sequences of the maternally inherited mitochondrial DNA (mtDNA), we show that close to one-half of Ashkenazi Jews, estimated at 8,000,000 people, can be traced back to only 4 women carrying distinct mtDNAs that are virtually absent in other populations, with the important exception of low frequencies among non-Ashkenazi Jews. We conclude that four founding mtDNAs, likely of Near Eastern ancestry, underwent major expansion(s) in Europe within the past millennium. 相似文献
155.
156.
157.
158.
159.
Alexej V. Sokolov Kira V. Ageeva Olga S. Cherkalina Maria O. Pulina Elena T. Zakharova Vladimir N. Prozorovskii Denis V. Aksenov Vadim B. Vasilyev Oleg M. Panasenko 《Chemistry and physics of lipids》2010,163(4-5):347-355
The first evidence of multi-component complexes formed by myeloperoxidase (MPO), ceruloplasmin (CP), and very low/low density lipoproteins (VLDL/LDL) obtained by electrophoresis, gel filtration, and photon-correlation spectroscopy (PCS) is presented in this paper. Complexes were observed when isolated MPO, CP, and VLDL/LDL were mixed and/or when MPO was added to the blood plasma. Complex LDL–MPO–CP was detected in 44 of 100 plasma samples taken from patients with atherosclerosis, and 33 of 44 samples also contained the VLDL–MPO–CP complex. MPO concentration in these patients’ plasma exceeded 800 ng/ml. Interaction of MPO with high density lipoproteins (HDL) was not revealed, as well as binding of CP to lipoproteins in the absence of MPO. Adding antibodies against apoB-100 to VLDL–MPO–CP and LDL–MPO–CP complexes results in release of lipoproteins. Using PCS the diameters of complexes under study were evaluated. By comparing concentrations of the components in complexes formed by MPO, CP, and lipoproteins their stoichiometry was assessed as 2VLDL:1MPO:2CP and 1LDL:1MPO:2CP. Lipoproteins affected the inhibition of MPO peroxidase activity by CP. The affinity of lipoproteins to MPO–CP complex was assessed using apparent dissociation constants determined as ~0.3 nM for VLDL and ~0.14 nM for LDL. 相似文献
160.