全文获取类型
收费全文 | 11233篇 |
免费 | 892篇 |
国内免费 | 8篇 |
专业分类
12133篇 |
出版年
2022年 | 61篇 |
2021年 | 100篇 |
2020年 | 56篇 |
2019年 | 92篇 |
2018年 | 131篇 |
2017年 | 146篇 |
2016年 | 198篇 |
2015年 | 356篇 |
2014年 | 391篇 |
2013年 | 525篇 |
2012年 | 633篇 |
2011年 | 661篇 |
2010年 | 446篇 |
2009年 | 443篇 |
2008年 | 590篇 |
2007年 | 668篇 |
2006年 | 637篇 |
2005年 | 641篇 |
2004年 | 614篇 |
2003年 | 617篇 |
2002年 | 624篇 |
2001年 | 154篇 |
2000年 | 138篇 |
1999年 | 180篇 |
1998年 | 216篇 |
1997年 | 164篇 |
1996年 | 144篇 |
1995年 | 144篇 |
1994年 | 133篇 |
1993年 | 157篇 |
1992年 | 185篇 |
1991年 | 136篇 |
1990年 | 146篇 |
1989年 | 119篇 |
1988年 | 101篇 |
1987年 | 96篇 |
1986年 | 73篇 |
1985年 | 119篇 |
1984年 | 103篇 |
1983年 | 79篇 |
1982年 | 101篇 |
1981年 | 84篇 |
1980年 | 75篇 |
1979年 | 78篇 |
1978年 | 63篇 |
1977年 | 77篇 |
1976年 | 70篇 |
1975年 | 47篇 |
1974年 | 47篇 |
1973年 | 52篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
231.
Florence Quesada Calvo Marianne Fillet Dr. Dominique de Seny Marie‐Alice Meuwis Raphael Maree Céline Crahay Geneviève Paulissen Natacha Rocks Maud Gueders Louis Wehenkel Marie‐Paule Merville Renaud Louis Jean‐Michel Foidart Agnes Noël Didier Cataldo 《Proteomics》2009,9(8):2163-2170
Asthma is a complex inflammatory disease of airways. A network of reciprocal interactions between inflammatory cells, peptidic mediators, extracellular matrix components, and proteases is thought to be involved in the installation and maintenance of asthma‐related airway inflammation and remodeling. To date, new proteic mediators displaying significant activity in the pathophysiology of asthma are still to be unveiled. The main objective of this study was to uncover potential target proteins by using surface‐enhanced laser desorption/ionization‐time of flight‐mass spectrometry (SELDI‐TOF‐MS) on lung samples from mouse models of allergen‐induced airway inflammation and remodeling. In this model, we pointed out several protein or peptide peaks that were preferentially expressed in diseased mice as compared to controls. We report the identification of different five proteins: found inflammatory zone 1 or RELMα (FIZZ‐1), calcyclin (S100A6), clara cell secretory protein 10 (CC10), Ubiquitin, and Histone H4. 相似文献
232.
Cysteine: Depolarization-Induced Release from Rat Brain In Vitro 总被引:1,自引:2,他引:1
Hans Jörg Keller Kim Quang Do Markus Zollinger Kaspar H. Winterhalter Michel Cuénod 《Journal of neurochemistry》1989,52(6):1801-1806
Compounds released on depolarization in a Ca2+-dependent manner from rat brain slices were screened to identify candidates for neuroactive substances. Lyophilized superfusates were analyzed by reversed-phase HPLC after derivatization with 9-fluorenyl N-succinimidyl carbonate. One of the compounds that showed an increase of concentration in superfusates in the presence of iodoacetamide was identified as the cysteine (Cys) derivative, S-carboxamidomethylcysteine, by fast atom bombardment mass spectrometry and other methods. This stable Cys derivative originates from endogenous, extracellular Cys. The finding led to a method for quantification of Cys in superfusates by immediate cooling of the superfusates to 0 degrees C and reaction of Cys with N-ethylmaleimide. Depolarization-induced Ca2+-dependent release of Cys was most prominent in the neocortex, followed by the mesodiencephalon, striatum, and cerebellum. This suggests that Cys is released from a neuronal compartment and might be involved in neurotransmission. 相似文献
233.
234.
235.
Urizar E Montanelli L Loy T Bonomi M Swillens S Gales C Bouvier M Smits G Vassart G Costagliola S 《The EMBO journal》2005,24(11):1954-1964
The monomeric model of rhodopsin-like G protein-coupled receptors (GPCRs) has progressively yielded the floor to the concept of GPCRs being oligo(di)mers, but the functional correlates of dimerization remain unclear. In this report, dimers of glycoprotein hormone receptors were demonstrated in living cells, with a combination of biophysical (bioluminescence resonance energy transfer and homogenous time resolved fluorescence/fluorescence resonance energy transfer), functional and biochemical approaches. Thyrotropin (TSHr) and lutropin (LH/CGr) receptors form homo- and heterodimers, via interactions involving primarily their heptahelical domains. The large hormone-binding ectodomains were dispensable for dimerization but modulated protomer interaction. Dimerization was not affected by agonist binding. Observed functional complementation indicates that TSHr dimers may function as a single functional unit. Finally, heterologous binding-competition studies, performed with heterodimers between TSHr and LH/CG-TSHr chimeras, demonstrated the unsuspected existence of strong negative cooperativity of hormone binding. Tracer desorption experiments indicated an allosteric behavior in TSHr and, to a lesser extent, in LH/CGr and FSHr homodimers. This study is the first report of homodimerization associated with negative cooperativity in rhodopsin-like GPCRs. As such, it may warrant revisitation of allosterism in the whole GPCR family. 相似文献
236.
237.
Claude Auriault Joël Pestel Michel Joseph Jean-Paul Dessaint Andre Capron 《Cellular immunology》1981,62(1):15-27
Discharge of lysosomal enzymes, measured by release of β-glucuronidase and cytotoxicity against Schistosoma mansoni schistosomula, was studied when rat macrophages were incubated in the presence of either IgG peptides, resulting from the cleavage of nonimmune IgG by parasitic proteases, or nonimmune aggregated IgG. With peptides, the macrophage activity showed a dramatic decrease while they were stimulated by IgG aggregates. In contrast, the synthesis of lymphocyte activating factor by macrophages was unaffected. The hydrolysis of IgG is carried out by two distinct enzymatic molecules released into the medium by the larvae. The mechanism by which nonimmune IgG peptides or aggregates inhibit or stimulate macrophage activity, regulated by both parameters indicated above, is discussed and is suggested as a general regulation mechanism for the macrophage activity required for parasite survival in the host. 相似文献
238.
Several lines of evidence indicate that the i.v. injection of 3H-pimozide results in a specific in vivo binding of the neuroleptic to dopaminergic receptors.First, 3H-pimozide is preferentially accumulated in the striatum as compared to non-dopaminergic structures like the cerebellum. Second, the selective accumulation of 3H-pimozide is prevented by prior administration of various neuroleptics as well as by apomorphine. Moreover, doses of antagonists which prevent this accumulation were identical to those which lead to an increased striatal HVA level. Third, 3H-pimozide accumulation is not modified by the administration of a variety of non-dopaminergic agents.However, 3H-pimozide binding is not prevented either by indirect dopamine agonists and is even greatly increased by d-amphetamine at high doses. The possibility that direct or indirect dopamine agonists may favour the binding of the antagonist through a modification of receptor sites is discussed. 相似文献
239.
The cellular growth ofChlamydomonas reinhardii is modified by the addition of a total exogenous histone fraction. These modifications may be related to chloroplast DNA replication; they are different according to the different classes of histones. The H1 subfraction seems to be responsible for the effect of the total histone fraction. 相似文献
240.
Intrauterine growth retardation induced by ligation of the uterine vessels in pregnant rats on the 5th day before delivery was associated with brain and body weights of hypotrophic offspring significantly lower than those of pair-aged control rats, even after 6 weeks of postnatal rearing under normal conditions. In vitro measurements in homogenates indicated that Na+/K+-ATPase in the forebrain, cerebellum and hippocampus was less active in hypotrophic rats than in pair-aged controls for at least the first month after birth. However, 5-HT and related agonists (RU-24969, bufotenine, and to a lower extent, tryptamine) stimulated Na+/K+-ATPase activity more efficiently in tissues from hypotrophic rats than in those from control animals. Opposite changes were noted in the brain stem: basal Na+/K+-ATPase activity was higher in hypotrophic rats during the second half of the first postnatal month but the stimulatory effect of 5-HT was lower than in pair-aged control animals. Since potent 5-HT antagonists such as cinanserin, methiothepin and methysergide, prevented the 5-HT induced-activation of Na+/K+-ATPase in brain homogenates, these results are discussed in relation with the possible existence of a specific 5-HT receptor controlling Na+/K+-ATPase activity in the rat brain. 相似文献