全文获取类型
收费全文 | 159231篇 |
免费 | 7305篇 |
国内免费 | 63篇 |
专业分类
166599篇 |
出版年
2021年 | 1207篇 |
2020年 | 1043篇 |
2019年 | 1089篇 |
2018年 | 3133篇 |
2017年 | 3119篇 |
2016年 | 5381篇 |
2015年 | 9297篇 |
2014年 | 9099篇 |
2013年 | 10198篇 |
2012年 | 10438篇 |
2011年 | 7471篇 |
2010年 | 5476篇 |
2009年 | 4730篇 |
2008年 | 4922篇 |
2007年 | 4611篇 |
2006年 | 4488篇 |
2005年 | 9863篇 |
2004年 | 8494篇 |
2003年 | 6389篇 |
2002年 | 3917篇 |
2001年 | 2690篇 |
2000年 | 1894篇 |
1999年 | 2710篇 |
1998年 | 1021篇 |
1992年 | 2570篇 |
1991年 | 2568篇 |
1990年 | 2567篇 |
1989年 | 2506篇 |
1988年 | 2452篇 |
1987年 | 2223篇 |
1986年 | 2033篇 |
1985年 | 2096篇 |
1984年 | 1559篇 |
1983年 | 1163篇 |
1982年 | 804篇 |
1981年 | 693篇 |
1979年 | 1359篇 |
1978年 | 1042篇 |
1977年 | 826篇 |
1976年 | 786篇 |
1975年 | 1100篇 |
1974年 | 1252篇 |
1973年 | 1271篇 |
1972年 | 1162篇 |
1971年 | 1106篇 |
1970年 | 1007篇 |
1969年 | 1018篇 |
1968年 | 916篇 |
1967年 | 908篇 |
1966年 | 722篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
41.
Marc Mercken Ursula Lübke Marc Vandermeeren Jan Gheuens A. Beate Oestreicher 《Developmental neurobiology》1992,23(3):309-321
The growth-associated protein B-50 also termed GAP-43, F1, pp46, P-57 and neuromodulin is a nervous tissuespecific protein kinase C (PKC) substrate that is considered to play a major role in neurite formation, regeneration, and neuroplasticity. We describe the isolation of seven mouse monoclonal antibodies (Mabs) directed against B-50. The Mabs are produced against the bovine B-50, selected by ELISA for cross-reactivity with its human counterpart, and evaluated on Western blots in comparison with the well-characterized affinity-purified rabbit polyclonal antibodies to rat-B-50. The Western blots show that the Mabs NM1, NM4, and NM6 recognize specifically the B-50 of bovine, human, and rat brain extract and the purified PKC phosphorylated and unphosphorylated rat B-50 isoforms. The Mabs NM2 and NM3 cross-react with bovine B-50 immunoreactive c-kinase substrate (BICKS), a protein sharing a 17 amino acid sequence homology with B-50. Two Mabs are useful for the detection of B-50 immunoreactivity in formalin-fixed human and rat brain tissues. In human specimen of the hippocampus, a characteristic neuropil distribution of B-50 is detected by the Mabs. In human muscle, Mabs reveal B-50 in nerve bundles and in axons at motor end plates. Thus, these Mabs are useful in investigating the function and localization of the B-50 protein. 相似文献
42.
I P Grigor'ev A A Neokesari?ski? 《Biulleten' eksperimental'no? biologii i meditsiny》1986,102(9):288-289
The effects of different concentrations of L-ascorbic acid (Asc) on Na+-dependent binding of 3H-GABA and 3H-DL-glutamic acid to rat brain cortical synaptosomes were studied. Asc, at a concentration nearly equal to brain extracellular one (3 X 10(-4) M), had no effect on specific and nonspecific 5H-GABA binding. At higher concentrations (10(-3) M) Asc strongly inhibited, and at lower concentrations (10(-6) M) considerably stimulated 3H-GABA binding. At a concentration of 10(-5)-10(-3) M Asc tended to decrease 3H-DL-glutamic acid binding. 相似文献
43.
D G Astaf'ev I V Maianskaia A K Akatov A N Maianski? 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1986,(7):48-51
In investigations based on the use of a highly sensitive test system permitting the detection of normal human antibodies to S. aureus peptidoglycan, the antigenic relationships between the peptidoglycans of S. aureus and other representatives of the genus Staphylococcus have been studied. Among other staphylococcal species, S. simulans, S. xylosus, S. hyicus, S. cohnii, S. hyicus s. s. chromogenes have been found to possess peptidoglycans most closely related to S. aureus peptidoglycans, while S. warneri and S. epidermidis peptidoglycans have proved to be least closely related to it. 相似文献
44.
ESR spectra of gamma-irradiated and frozen at 77 K human oxyhemoglobin and partially denaturated methemoglobin solutions were analysed. The quartet signal ascribed to the anion-radical of proximal histidine was shown to dominate in the spectra of both solutions. The spectra of methemoglobin solution irradiated with relatively small doses have an intensive singlet ascribed to the stabilized electron. The formation mechanism of free radicals is discussed. 相似文献
45.
Interaction between cytotoxin of the Central Asia cobra venom and dimiristoylphosphatidylcholine bilayer depending on its phase state was studied by ESR with spin label. A conclusion can be drawn that the efficiency of cytotoxin effect on the membranes depends on their phase state. Cytotoxin molecules are incorporated into myophile region of the bilayer, only if the latter is in the liquid crystal state. The interaction between cytotoxins and lipids of the bilayer in a gel state is in the main conditioned by electrostatic forces. 相似文献
46.
47.
48.
49.
Indomethacin and substance BW-755C in experiments on isolated myometrium striae of pregnant white rats exert an inhibiting effect on the contractile uterus function due to inhibition of cyclooxygenase or lipoxygenase ways of the arachidonic acid transformation. Prostaglandin F2 alpha is sensitive to functioning of the cyclooxygenase and lipoxygenase ways of the arachidonic acid transformation, while oxytocin--only lipoxygenase one. Conclusions rest on results from multiparametric analysis of the contractile uterus function suggested by authors and confirmed by the pattern recognition method--the Karunen-Loev orthogonal decomposition. 相似文献
50.