全文获取类型
收费全文 | 346篇 |
免费 | 41篇 |
国内免费 | 32篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 17篇 |
2012年 | 21篇 |
2011年 | 27篇 |
2010年 | 18篇 |
2009年 | 19篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 29篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1992年 | 8篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1971年 | 2篇 |
1963年 | 2篇 |
1959年 | 2篇 |
1958年 | 3篇 |
1957年 | 2篇 |
1955年 | 3篇 |
1949年 | 5篇 |
1948年 | 2篇 |
排序方式: 共有419条查询结果,搜索用时 429 毫秒
221.
222.
223.
MARCOS JOSÉ DA SILVA MARGARETH FERREIRA DE SALES 《Botanical journal of the Linnean Society. Linnean Society of London》2008,158(1):78-81
Phyllanthus retroflexus Brade is reinstated. It and the very similar P. subemarginatus Müll. Arg. are described, illustrated, and their relationships are discussed, based on a morphological analysis of herbarium specimens. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 78–81. 相似文献
224.
225.
226.
de Keyzer J van der Does C Kloosterman TG Driessen AJ 《The Journal of biological chemistry》2003,278(32):29581-29586
Translocase mediates the transport of preproteins across the inner membrane of Escherichia coli. SecA binds with high affinity to the membrane-embedded protein-conducting SecYEG complex and serves as both a receptor for secretory proteins and as an ATP-driven molecular motor. Cycles of ATP binding and hydrolysis by SecA drive the progressive movement of the preprotein across the membrane. Surface plasmon resonance allows an online monitoring of protein interactions. Here we report on the kinetic analysis of the interaction between SecA and the membrane-embedded SecYEG complex. Immobilization of membrane vesicles containing overproduced SecYEG on the Biacore Pioneer L1 chip allows the detection of high affinity SecA binding to the SecYEG complex and online monitoring of the translocation of the secretory protein proOmpA. SecA binds tightly to the SecYEG.proOmpA complex and is released only upon ATP hydrolysis. The results provide direct evidence for a model in which SecA cycles at the SecYEG complex during translocation. 相似文献
227.
Kloosterman DA Goodwin JT Burton PS Conradi RA Stockman BJ Scahill TA Blinn JR 《Biopolymers》2000,53(5):396-410
Efficient transport of intact drug (solute) across the intestinal epithelium is typically a requirement for good oral activity. In general, the membrane permeability of a solute is a complex function of its size, lipophilicity, hydrogen bond potential, charge, and conformation. In conjunction with theoretical/computational and in vitro drug transport studies, seven dipeptide (R(1)-D-Xaa-D-Phe-NHMe) homologues were each dissolved in a micellar d(38)-dodecylphosphocholine solvent system. In this homologous dipeptide series, factors such as size, lipophilicity, hydrogen-bond potential, and charge were either tightly controlled or well-characterized by other methods in order to investigate by nmr how conformational factors relate to transport. Nuclear Overhauser effect spectroscopy experiments and amide-NH-H(2)O chemical exchange rates showed that the five more lipophilic dipeptides were predominately associated with micelle, whereas the two less lipophilic analogues were not. Rotating frame nuclear Overhauser effect spectroscopy derived interproton distance restraints for each analogue, along with (3)J(HH)-derived dihedral restraints, were used in molecular dynamics/simulated annealing computations. Our results suggest that-other factors being equal-flexible dipeptides having a propensity to fold together nonpolar N- and C-terminal moieties allow greater segregation of polar and nonpolar domains and may possess enhanced transport characteristics. Dipeptides that were less flexible or that retained a less amphiphilic conformation did not have comparably enhanced transport characteristics. We suggest that these conformational/transport correlations may hold true for small, highly functionalized solutes (drugs) in general. 相似文献
228.
The zebrafish has become a major model system for biomedical research and is an emerging model for the study of behaviour. While adult zebrafish express a visually mediated shoaling preference, the onset of shoaling behaviour and of this preference is unknown. To assess the onset of these behaviours, we first manipulated the early social environment of larval zebrafish subjects, giving them three model shoaling partners of the same pigment phenotype. We then assayed the subjects' preferences using binary preference tests in which we presented subjects with two shoals, one shoal of fish exhibiting the same pigment pattern phenotype as their models and another shoal with a radically different pigment pattern. To determine whether or not the visually mediated preference could be altered once it was established, we further manipulated the social environment of a number of subjects, rearing them with one model shoal and testing them, then changing their social consorts and retesting them. Our results demonstrate that larval zebrafish shoal early in their development, but do not exhibit a shoaling preference until they are juveniles. Moreover, we find that the shoaling preference is stable, as changing the social environment of fish after they had acquired a preference did not change their preference. These data will facilitate investigations into the mechanisms underlying social behaviour in this vertebrate model system. 相似文献
229.
230.
An experimentally supported model of the Bacillus subtilis global transcriptional regulatory network
下载免费PDF全文
![点击此处可从《Molecular systems biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)