全文获取类型
收费全文 | 4775篇 |
免费 | 311篇 |
国内免费 | 293篇 |
出版年
2024年 | 6篇 |
2023年 | 53篇 |
2022年 | 110篇 |
2021年 | 270篇 |
2020年 | 192篇 |
2019年 | 208篇 |
2018年 | 161篇 |
2017年 | 136篇 |
2016年 | 215篇 |
2015年 | 315篇 |
2014年 | 336篇 |
2013年 | 360篇 |
2012年 | 493篇 |
2011年 | 405篇 |
2010年 | 232篇 |
2009年 | 227篇 |
2008年 | 236篇 |
2007年 | 189篇 |
2006年 | 175篇 |
2005年 | 136篇 |
2004年 | 111篇 |
2003年 | 98篇 |
2002年 | 103篇 |
2001年 | 85篇 |
2000年 | 76篇 |
1999年 | 69篇 |
1998年 | 45篇 |
1997年 | 40篇 |
1996年 | 36篇 |
1995年 | 42篇 |
1994年 | 39篇 |
1993年 | 24篇 |
1992年 | 30篇 |
1991年 | 33篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1969年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有5379条查询结果,搜索用时 31 毫秒
171.
Chunbin Zou Yan Chen Rebecca M. Smith Courtney Snavely Jin Li Tiffany A. Coon Bill B. Chen Yutong Zhao Rama K. Mallampalli 《The Journal of biological chemistry》2013,288(9):6306-6316
Histone acetyltransferase binding to origin recognition complex (HBO1) plays a crucial role in DNA replication licensing and cell proliferation, yet its molecular regulation in cells is relatively unknown. Here an uncharacterized protein, Fbxw15, directly interacts with HBO1, a labile protein (t½ = ∼3 h), to mediate its ubiquitination (Lys338) and degradation in the cytoplasm. Fbxw15-mediated HBO1 depletion required mitogen-activated protein kinase 1 (Mek1), which was sufficient to trigger HBO1 phosphorylation and degradation in cells. Mek1 ability to produce HBO1 degradation was blocked by Fbxw15 silencing. Lipopolysaccharide induced HBO1 degradation, an effect abrogated by Fbxw15 or Mek1 cellular depletion. Modulation of Fbxw15 levels was able to differentially regulate histone H3K14 acetylation and cellular proliferation by altering HBO1 levels. These studies authenticate Fbxw15 as a ubiquitin E3 ligase subunit that mediates endotoxin-induced HBO1 depletion in cells, thereby controlling cell replicative capacity. 相似文献
172.
Zou Keyuan 《Ocean Development & International Law》2013,44(1):69-93
The United States is the sole superpower in the contemporary world and its role in the development of the law of the sea cannot be ignored. Although having not yet acceded to the U.N. Convention on the Law of the Sea, the United States has contributed to the development of the international law of the sea in numerous ways, including responding to the so-called excessive maritime claims in East Asia and creating new rules of maritime enforcement. This article assesses this recent U.S. practice. 相似文献
173.
In January 1998, Taiwan promulgated the Law of the Republic of China (ROC) on the Territorial Sea and the Contiguous Zone and the Law of the Republic of China on the Exclusive Economic Zone (EEZ) and the Continental Shelf, both of which came into force on January 21, 1998. On June 26, 1998, China adopted the Law of the People's Republic of China on the Exclusive Economic Zone and the Continental Shelf, which is the most significant maritime legislation since its 1992 Law on the Territorial Sea and the Contiguous Zone. This article studies the recent maritime legislation developments in Mainland China and Taiwan, the differences and similarities between the two sets of laws, their implications for the Asia-Pacific region, and the potential challenges for the United States. 相似文献
174.
175.
Qiang Zhang Richou Han Zhongliang Huang Fasheng Zou 《Biodiversity and Conservation》2013,22(9):1965-1989
As forests undergo natural succession following artificial afforestation, their bird assemblages also change. However, interspecific avian social organization associated with forest succession has not been fully understood, particularly for mixed-species bird flocks. To disentangle how mixed-species flocks change as a function of local forest structure, we analyzed flock characteristics (particularly species richness, flocking frequency and propensity) and vegetation physiognomies along a presumed successional series (early, middle, and advanced) simultaneously in subtropical forests in southern China. As hypothesized, monthly point counts demonstrated that complexity of flocks increases with the progression of natural forest succession at a local scale. Advanced forests differed significantly from pioneering plantations with respect to vegetation structure, flock characteristics and constituents (especially for understory specialists). Importantly, forest succession affected flock patterns particularly in relation to the flocking propensity of regular species, and the frequency of nuclear species (Huet’s fulvetta Alcippe hueti), which in turn determined flocking occurrence at different successional stands. Canonical correspondence analysis indicated that understory flocking species (mainly Timaliidae babblers) were significantly associated with intact native canopy cover, complex DBH diversity, as well as high densities of dead trees and large trees, representing a maturity level of successional stands. Our study reveals that the effect of natural forest succession on mixed-species bird flocks is species-specific and guild-dependent. From a conservation perspective, despite a high proliferation of pine plantation in southern China, priority should be placed on protecting the advanced forest with a rich collection of understory flocking specialists. 相似文献
176.
Peter W. Glunz Xiaojun Zhang Yan Zou Indawati Delucca Alexandra H. Nirschl Xuhong Cheng Carolyn A. Weigelt Daniel L. Cheney Anzhi Wei Rushith Anumula Joseph M. Luettgen Alan R. Rendina Mark Harpel Gang Luo Robert Knabb Pancras C. Wong Ruth R. Wexler E. Scott Priestley 《Bioorganic & medicinal chemistry letters》2013,23(18):5244-5248
Aminoisoquinoline and isoquinoline groups have successfully replaced the more basic P1 benzamidine group of an acylsulfonamide factor VIIa inhibitor. Inhibitory activity was optimized by the identification of additional hydrophobic and hydrophilic P′ binding interactions. The molecular details of these interactions were elucidated by X-ray crystallography and molecular modeling. We also show that decreasing the basicity of the P1 group results in improved oral bioavailability in this chemotype. 相似文献
177.
Xianwen Cao Jing Jiang Shoude Zhang Lili Zhu Juan Zou Yanyan Diao Weilie Xiao Lei Shan Handong Sun Weidong Zhang Jin Huang Honglin Li 《Bioorganic & medicinal chemistry letters》2013,23(11):3329-3333
Eleven compounds were identified as estrogen receptor modulators from an in-house natural product database (NPD) by structure-based virtual screening for ERα and ERβ. Among them, 3 compounds were confirmed as ER agonists and 8 compounds were confirmed as ER antagonists by yeast two-hybrid (Y2H) assay, with EC50 values ranging from several micromolar to 100 micromolar. In this study, a novel series of cycloartane triterpenoids isolated from Schisandra glaucescens Diels was found to have ER antagonistic effect, the most potent antagonist of which exhibited activity with EC50 value of 2.55 and 4.68 μM for ERα and ERβ, respectively. Moreover, the types of modulation and subtype selectivity were also investigated through molecular docking simulation. 相似文献
178.
YP Chen MQ Zou C Qi MX Xie DN Wang YF Wang Q Xue JF Li Y Chen 《Biosensors & bioelectronics》2013,39(1):112-117
A rapid, sensitive, and simple immunosensor was developed for the detection of Kanamycin (KM) in milk. This immunosensor is based on magnetic relaxation switch (MRS) assay and biotin-streptavidin system (B-SA system). The target analyte (KM) competed with those on the surface of the superparamagnetic iron oxide (SPIO) nanoparticles and hence affected the formation of SPIO aggregates. The dispersed and aggregated states of SPIO can modulate the spin-spin relaxation time (T(2)) of the neighboring water molecule. T(2) was then changed as an effect of the target analyte. The B-SA system was used to amplify the SPIO binding, thus enhance the sensitivity. The detection working was 1.5 to 25.2ngmL(-1) and limit of detection (LOD) was determined to be 0.1ngmL(-1). The LOD of the immunosensor decreased tenfold, and its analysis time (45min) was much shorter than that of enzyme-linked immunosorbent assay (6h to 8h). The average recoveries of the KM at various spiking levels ranged from 80.2% to 85.6% with a relative standard deviation (RSD) below 4.0%. The results showed that the MRS immunosensor was a promising platform for the determination of small molecular residues because of its high sensitivity, specificity, homogeneity, and speed. 相似文献
179.
180.
- Download : Download full-size image