全文获取类型
收费全文 | 12742篇 |
免费 | 1006篇 |
国内免费 | 5篇 |
专业分类
13753篇 |
出版年
2023年 | 77篇 |
2022年 | 101篇 |
2021年 | 195篇 |
2020年 | 169篇 |
2019年 | 154篇 |
2018年 | 363篇 |
2017年 | 326篇 |
2016年 | 407篇 |
2015年 | 575篇 |
2014年 | 607篇 |
2013年 | 778篇 |
2012年 | 1120篇 |
2011年 | 1120篇 |
2010年 | 631篇 |
2009年 | 490篇 |
2008年 | 903篇 |
2007年 | 832篇 |
2006年 | 766篇 |
2005年 | 717篇 |
2004年 | 690篇 |
2003年 | 577篇 |
2002年 | 531篇 |
2001年 | 150篇 |
2000年 | 130篇 |
1999年 | 104篇 |
1998年 | 80篇 |
1997年 | 73篇 |
1996年 | 70篇 |
1995年 | 66篇 |
1994年 | 45篇 |
1993年 | 63篇 |
1992年 | 58篇 |
1991年 | 36篇 |
1990年 | 53篇 |
1989年 | 30篇 |
1988年 | 27篇 |
1987年 | 26篇 |
1986年 | 27篇 |
1985年 | 39篇 |
1984年 | 39篇 |
1983年 | 49篇 |
1982年 | 42篇 |
1981年 | 28篇 |
1980年 | 34篇 |
1979年 | 32篇 |
1978年 | 35篇 |
1977年 | 23篇 |
1976年 | 30篇 |
1975年 | 28篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
A survey on attitudes toward large carnivores was conducted in a representative sample of the Norwegian population (n = 3134). People were asked about the acceptability of carnivores living in remote wilderness, close to where people live, killing livestock, killing pets, or threatening humans. Large differences in acceptability appeared across the five situations. Wolves and bears were less acceptable than lynx and wolverines when observed close to where people live. Negative associations were found between acceptability and lack of personal control, economic loss, and respondents' age. Acceptability was higher among males than among females, and higher among urban than among rural residents. The results showed that general measures of attitudes alone toward large carnivores were of limited value in wildlife management. The situational and social specificity of these attitudes should be given more attention. 相似文献
42.
43.
44.
45.
María Capa João Miguel de Matos Nogueira Maíra Cappellani Silva Rossi 《Journal of morphology》2011,272(3):302-319
Fan worms (Sabellidae) possess paired modified prostomial structures at the base of the radiolar crown, dorso‐lateral to the mouth, called dorsal lips. The dorsal lips are involved in the sorting of particles collected by the radiolar crown. The range of variation in the morphology of dorsal lips is extensive, and probably this is not only due to adaptations to different environments and feeding preferences but also due to phylogenetic constraints. In this study, we describe and compare the morphology of dorsal lips in a range of sabellid taxa based on histological cross‐sections of these structures, and compare our data and terminology with those of previous studies. Dorsal lips are maintained erect in most taxa by a modified radiole fused to them known as dorsal radiolar appendage. We suggest that dorsal radiolar appendages with an internal supporting axis (cellular or acellular) and probably also the ventral lips are synapomorphies of the family. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc. 相似文献
46.
Marques-Carvalho MJ Sahoo N Muskett FW Vieira-Pires RS Gabant G Cadene M Schönherr R Morais-Cabral JH 《Journal of molecular biology》2012,423(1):34-46
KCNH channels are voltage-gated potassium channels with important physiological functions. In these channels, a C-terminal cytoplasmic region, known as the cyclic nucleotide binding homology (CNB-homology) domain displays strong sequence similarity to cyclic nucleotide binding (CNB) domains. However, the isolated domain does not bind cyclic nucleotides. Here, we report the X-ray structure of the CNB-homology domain from the mouse EAG1 channel. Through comparison with the recently determined structure of the CNB-homology domain from the zebrafish ELK (eag-like K(+)) channel and the CNB domains from the MlotiK1 and HCN (hyperpolarization-activated cyclic nucleotide-gated) potassium channels, we establish the structural features of CNB-homology domains that explain the low affinity for cyclic nucleotides. Our structure establishes that the "self-liganded" conformation, where two residues of the C-terminus of the domain are bound in an equivalent position to cyclic nucleotides in CNB domains, is a conserved feature of CNB-homology domains. Importantly, we provide biochemical evidence that suggests that there is also an unliganded conformation where the C-terminus of the domain peels away from its bound position. A functional characterization of this unliganded conformation reveals a role of the CNB-homology domain in channel gating. 相似文献
47.
48.
49.
de Vries SJ van Dijk AD Krzeminski M van Dijk M Thureau A Hsu V Wassenaar T Bonvin AM 《Proteins》2007,69(4):726-733
Here we present version 2.0 of HADDOCK, which incorporates considerable improvements and new features. HADDOCK is now able to model not only protein-protein complexes but also other kinds of biomolecular complexes and multi-component (N > 2) systems. In the absence of any experimental and/or predicted information to drive the docking, HADDOCK now offers two additional ab initio docking modes based on either random patch definition or center-of-mass restraints. The docking protocol has been considerably improved, supporting among other solvated docking, automatic definition of semi-flexible regions, and inclusion of a desolvation energy term in the scoring scheme. The performance of HADDOCK2.0 is evaluated on the targets of rounds 4-11, run in a semi-automated mode using the original information we used in our CAPRI submissions. This enables a direct assessment of the progress made since the previous versions. Although HADDOCK performed very well in CAPRI (65% and 71% success rates, overall and for unbound targets only, respectively), a substantial improvement was achieved with HADDOCK2.0. 相似文献
50.