全文获取类型
收费全文 | 5748篇 |
免费 | 524篇 |
国内免费 | 1篇 |
出版年
2023年 | 42篇 |
2022年 | 73篇 |
2021年 | 215篇 |
2020年 | 90篇 |
2019年 | 128篇 |
2018年 | 147篇 |
2017年 | 133篇 |
2016年 | 214篇 |
2015年 | 390篇 |
2014年 | 414篇 |
2013年 | 442篇 |
2012年 | 564篇 |
2011年 | 515篇 |
2010年 | 312篇 |
2009年 | 223篇 |
2008年 | 314篇 |
2007年 | 302篇 |
2006年 | 245篇 |
2005年 | 224篇 |
2004年 | 174篇 |
2003年 | 195篇 |
2002年 | 175篇 |
2001年 | 64篇 |
2000年 | 67篇 |
1999年 | 57篇 |
1998年 | 41篇 |
1997年 | 29篇 |
1996年 | 20篇 |
1995年 | 26篇 |
1994年 | 14篇 |
1993年 | 19篇 |
1992年 | 33篇 |
1991年 | 41篇 |
1990年 | 44篇 |
1989年 | 29篇 |
1988年 | 31篇 |
1987年 | 23篇 |
1986年 | 13篇 |
1985年 | 20篇 |
1984年 | 18篇 |
1983年 | 13篇 |
1982年 | 15篇 |
1981年 | 11篇 |
1979年 | 13篇 |
1978年 | 14篇 |
1977年 | 11篇 |
1973年 | 11篇 |
1972年 | 9篇 |
1971年 | 7篇 |
1969年 | 7篇 |
排序方式: 共有6273条查询结果,搜索用时 265 毫秒
1.
The mechanisms controlling early adenovirus gene expression in vivo have been studied using inhibitors of protein synthesis. When inhibitors were added shortly before or at the onset of infection, viral mRNA from all early regions was transcribed, spliced and accumulated over a 7 hr period. After longer pretreatment, accumulation of several early mRNAs were suppressed. Addition of inhibitors 1 hr after infection enhanced the accumulation of viral mRNA in the cytoplasm. Translation of early mRNA selected on adenovirus DNA in a cell-free system reflected the amount of viral mRNA present. A viral coded product may therefore control accumulation of viral mRNA.A different pattern emerged when inhibitors of protein synthesis were removed at 5 hr postinfection and cells were pulse-labeled in vivo. If inhibitors were introduced at or before infection, early viral proteins were synthesized only after a lag of 1–3 hr. However, if treatment was introduced 1 hr post-infection, reversion of the protein synthesis block was instantaneous. It appears that protein synthesis inhibitors reveal an in vivo translational block for viral mRNA. This block could be overcome by preinfection with a related virus. Furthermore, no block was observed in a virus-transformed human embryonic kidney cell line (293) which expresses early region 1 of the viral genome. Viral gene product(s) encoded in early region 1 may control translation of early adenovirus messenger RNA in vivo. 相似文献
2.
3.
Antoine Wystrach Sebastian Schwarz Patrick Schultheiss Guy Beugnon Ken Cheng 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(2):167-179
The Australian desert ant Melophorus bagoti often follows stereotypical routes through a cluttered landscape containing both distant panoramic views and obstacles (plants)
to navigate around. We created an artificial obstacle course for the ants between a feeder and their nest. Landmarks comprised
natural objects in the landscape such as logs, branches, and tussocks. Many ants travelled stereotypical routes home through
the obstacle course in training, threading repeatedly the same gaps in the landmarks. Manipulations altering the relations
between the landmarks and the surrounding panorama, however, affected the routes in two major ways. Both interchanging the
positions of landmarks (transpositions) and displacing the entire landmark set along with the starting position of the ants
(translations) (1) reduced the stereotypicality of the route, and (2) increased turns and meanders during travel. The ants
might have used the entire panorama in view-based travel, or the distal panorama might prime the identification and use of
landmarks en route. Despite the large data set, both options (not mutually exclusive) remain viable. 相似文献
4.
zge Karayel Francesca Tonelli Sebastian Virreira Winter Phillip E. Geyer Ying Fan Esther M. Sammler Dario R. Alessi Martin Steger Matthias Mann 《Molecular & cellular proteomics : MCP》2020,19(9):1546-1560
Highlights
- •MS-based clinical assay that accurately determines phospho Rab10 occupancy.
- •Stable isotope labeled phosphopeptide injected as a standard with endogenous tryptic phospho Rab peptide for accurate ratio determination.
- •Determination of pRab levels in neutrophils of Parkinson disease patients.
- •Relevance of pRab levels as marker of PD.
5.
Krzysztof J. Gorgolewski Dan Lurie Sebastian Urchs Judy A. Kipping R. Cameron Craddock Michael P. Milham Daniel S. Margulies Jonathan Smallwood 《PloS one》2014,9(5)
Although neural activity often reflects the processing of external inputs, intrinsic fluctuations in activity have been observed throughout the brain. These may relate to patterns of self-generated thought that can occur while not performing goal-driven tasks. To understand the relationship between self-generated mental activity and intrinsic neural fluctuations, we developed the New York Cognition Questionnaire (NYC-Q) to assess the content and form of an individual''s experiences during the acquisition of resting-state fMRI data. The data were collected as a part of the Nathan Kline Rockland Enhanced sample. We decomposed NYC-Q scores using exploratory factor analysis and found that self-reported thoughts clustered into distinct dimensions of content (future related, past related, positive, negative, and social) and form (words, images, and specificity). We used these components to perform an individual difference analysis exploring how differences in the types of self-generated thoughts relate to whole brain measures of intrinsic brain activity (fractional amplitude of low frequency fluctuations, regional homogeneity, and degree centrality). We found patterns of self-generated thoughts related to changes that were distributed across a wide range of cortical areas. For example, individuals who reported greater imagery exhibited greater low frequency fluctuations in a region of perigenual cingulate cortex, a region that is known to participate in the so-called default-mode network. We also found certain forms of thought were associated with other areas, such as primary visual cortex, the insula, and the cerebellum. For example, individuals who reported greater future thought exhibited less homogeneous neural fluctuations in a region of lateral occipital cortex, a result that is consistent with the claim that particular types of self-generated thought depend on processes that are decoupled from sensory processes. These data provide evidence that self-generated thought is a heterogeneous category of experience and that studying its content can be helpful in understanding brain dynamics. 相似文献
6.
7.
Sebastian Kalamajski Dominique Bihan Arkadiusz Bonna Kristofer Rubin Richard W. Farndale 《The Journal of biological chemistry》2016,291(15):7951-7960
The hallmark of fibrotic disorders is a highly cross-linked and dense collagen matrix, a property driven by the oxidative action of lysyl oxidase. Other fibrosis-associated proteins also contribute to the final collagen matrix properties, one of which is fibromodulin. Its interactions with collagen affect collagen cross-linking, packing, and fibril diameter. We investigated the possibility that a specific relationship exists between fibromodulin and lysyl oxidase, potentially imparting a specific collagen matrix phenotype. We mapped the fibromodulin-collagen interaction sites using the collagen II and III Toolkit peptide libraries. Fibromodulin interacted with the peptides containing the known collagen cross-linking sites and the MMP-1 cleavage site in collagens I and II. Interestingly, the interaction sites are closely aligned within the quarter-staggered collagen fibril, suggesting a multivalent interaction between fibromodulin and several collagen helices. Furthermore, we detected an interaction between fibromodulin and lysyl oxidase (a major collagen cross-linking enzyme) and mapped the interaction site to 12 N-terminal amino acids on fibromodulin. This interaction also increases the activity of lysyl oxidase. Together, the data suggest a fibromodulin-modulated collagen cross-linking mechanism where fibromodulin binds to a specific part of the collagen domain and also forms a complex with lysyl oxidase, targeting the enzyme toward specific cross-linking sites. 相似文献
8.
9.
10.
Differential permeabilization of membranes by saponin treatment of isolated rat hepatocytes. Release of secretory proteins. 总被引:10,自引:1,他引:9 下载免费PDF全文
Monolayer cultures of rat hepatocytes were treated with increasing concentrations of saponin (prepared from Gypsophila plants) for 30 min at 6 degrees C. Differential permeabilization of the intracellular membranes could be demonstrated: at 0.040 mg of saponin/ml the plasma membrane was permeabilized, as assessed by the release of 50% of the total cellular amount of lactate dehydrogenase, and at 0.20 mg/ml the endoplasmic reticulum was permeabilized, as measured by the release of 50% of pulse-35S-labelled albumin. The Golgi complex was permeabilized at an intermediate saponin concentration, as indicated by the release of homogeneously 35S-labelled albumin; about half the intracellular albumin is located in this organelle. At 1.0 up to 5.0 mg of saponin/ml 90-95% of the radioactively labelled albumin was released. Even at 5.0 mg/ml less than 10% of the membrane of the endoplasmic reticulum was solubilized, as judged by the degree of release of a membrane-bound enzyme specific for this organelle. These results demonstrate the usefulness of saponin as a tool for investigating the interior of different intracellular compartments. 相似文献