全文获取类型
收费全文 | 11107篇 |
免费 | 715篇 |
国内免费 | 2篇 |
出版年
2023年 | 73篇 |
2021年 | 129篇 |
2020年 | 116篇 |
2019年 | 137篇 |
2018年 | 229篇 |
2017年 | 243篇 |
2016年 | 338篇 |
2015年 | 437篇 |
2014年 | 474篇 |
2013年 | 688篇 |
2012年 | 797篇 |
2011年 | 764篇 |
2010年 | 473篇 |
2009年 | 400篇 |
2008年 | 613篇 |
2007年 | 564篇 |
2006年 | 559篇 |
2005年 | 486篇 |
2004年 | 484篇 |
2003年 | 433篇 |
2002年 | 409篇 |
2001年 | 215篇 |
2000年 | 163篇 |
1999年 | 148篇 |
1998年 | 90篇 |
1997年 | 82篇 |
1996年 | 70篇 |
1995年 | 72篇 |
1994年 | 56篇 |
1993年 | 59篇 |
1992年 | 103篇 |
1991年 | 77篇 |
1990年 | 91篇 |
1989年 | 107篇 |
1988年 | 88篇 |
1987年 | 64篇 |
1986年 | 82篇 |
1985年 | 98篇 |
1983年 | 64篇 |
1982年 | 53篇 |
1981年 | 55篇 |
1979年 | 87篇 |
1978年 | 57篇 |
1974年 | 82篇 |
1973年 | 77篇 |
1972年 | 52篇 |
1970年 | 69篇 |
1969年 | 63篇 |
1968年 | 59篇 |
1967年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
381.
382.
383.
Hadhemi Kaddour Yosra Hamdi David Vaudry Magalie Basille Laurence Desrues Jérôme Leprince Hélène Castel Hubert Vaudry Marie‐Christine Tonon Mohamed Amri Olfa Masmoudi‐Kouki 《Journal of neurochemistry》2013,125(4):620-633
Oxidative stress, induced by various neurodegenerative diseases, initiates a cascade of events leading to apoptosis, and thus plays a critical role in neuronal injury. In this study, we have investigated the potential neuroprotective effect of the octadecaneuropeptide (ODN) on 6‐hydroxydopamine (6‐OHDA)‐induced oxidative stress and apoptosis in cerebellar granule neurons (CGN). ODN, which is produced by astrocytes, is an endogenous ligand for both central‐type benzodiazepine receptors (CBR) and a metabotropic receptor. Incubation of neurons with subnanomolar concentrations of ODN (10?18 to 10?12 M) inhibited 6‐OHDA‐evoked cell death in a concentration‐dependent manner. The effect of ODN on neuronal survival was abrogated by the metabotropic receptor antagonist, cyclo1–8[DLeu5]OP, but not by a CBR antagonist. ODN stimulated polyphosphoinositide turnover and ERK phosphorylation in CGN. The protective effect of ODN against 6‐OHDA toxicity involved the phospholipase C/ERK MAPK transduction cascade. 6‐OHDA treatment induced an accumulation of reactive oxygen species, an increase of the expression of the pro‐apoptotic gene Bax, a drop of the mitochondrial membrane potential and a stimulation of caspase‐3 activity. Exposure of 6‐OHDA‐treated cells to ODN blocked all the deleterious effects of the toxin. Taken together, these data demonstrate for the first time that ODN is a neuroprotective agent that prevents 6‐OHDA‐induced oxidative stress and apoptotic cell death. 相似文献
384.
Dóra K. Menyhárd Anna Kiss-Szemán éva Tichy-Rács Balázs Hornung Krisztina Rádi Zoltán Szeltner Klarissza Domokos Ilona Szamosi Gábor Náray-Szabó László Polgár Veronika Harmat 《The Journal of biological chemistry》2013,288(24):17884-17894
Oligopeptidases impose a size limitation on their substrates, the mechanism of which has long been under debate. Here we present the structure of a hexameric serine protease, an oligopeptidase from Pyrococcus horikoshii (PhAAP), revealing a complex, self-compartmentalized inner space, where substrates may access the monomer active sites passing through a double-gated “check-in” system, first passing through a pore on the hexamer surface and then turning to enter through an even smaller opening at the monomers'' domain interface. This substrate screening strategy is unique within the family. We found that among oligopeptidases, a residue of the catalytic apparatus is positioned near an amylogenic β-edge, which needs to be protected to prevent aggregation, and we found that different oligopeptidases use different strategies to achieve such an end. We propose that self-assembly within the family results in characteristically different substrate selection mechanisms coupled to different multimerization states. 相似文献
385.
Jérôme Fuchs Juan L. Parra Steven M. Goodman Marie Jeanne Raherilalao Jeremy Vanderwal Rauri C. K. Bowie 《Biological journal of the Linnean Society. Linnean Society of London》2013,108(3):658-676
We conduct a phylogeographic study of the Crested Drongo (Dicrurus forficatus forficatus), a broadly distributed bird species on Madagascar. We first determined the demographic and spatial pattern inferred from mitochondrial and nuclear data, and then compared these results with predictions from a present to 0.120‐Myr‐old reconstruction of the spatial dynamics of the range of D. f. forficatus on Madagascar, enabling putative areas of stability (lineage persistence) to be detected. Weak genetic structure along an east–west pattern and comparatively low genetic diversity were recovered, with strong evidence of population expansion found at all ten loci sampled. The palaeoclimatic distribution models over the past 0.120 Myr suggest the presence of extensive areas of suitable climate in the east and west for the species since its colonization of Madagascar, a result in strong concordance with the spatial and genetic signal derived from our multilocus data set. © 2013 The Linnean Society of London 相似文献
386.
Nil Rahola Jér?me Depaquit Boris Kevin Makanga Christophe Paupy 《Memórias do Instituto Oswaldo Cruz》2013,108(7):845-849
During a research project aimed at the study of the Culicinae fauna of Gabon and
carried out in the National Park of La Lopé, we captured an unknown sandfly male
specimen (genus Phlebotomus) by CDC miniature light trap
belonging to a new species for Science. Furthermore, the originality of his
genitalia does not allow us to include this species in one of the existing
subgenus, thus in this paper we propose the creation of a new subgenus, as
Phlebotomus (Legeromyia) multihamatus sp. nov., subg. nov.
described from the National Park of La Lopé, through one male captured with CDC
miniature light trap. A new species and a new subgenus of sandfly is
characterised by a short style with three spines, a paramere wearing a basal
hook as well as a basal pouch and the absence of basal lobe on the coxite. The
originality of the genitalia of the male gives way to discussion about potential
primary homologies between P. multihamatus sp. nov. and
Phlebotomus (Abonnencius) fortunatarum, Phlebotomus
(Anaphlebotomus) stantoni and Phlebotomus (Euphlebotomus)
argentipes, which should be verified for future studies. The
discovery of this new species in Gabon must encourage the study of sandflies in
this country. 相似文献
387.
388.
389.