全文获取类型
收费全文 | 1117篇 |
免费 | 27篇 |
出版年
2021年 | 15篇 |
2019年 | 15篇 |
2018年 | 18篇 |
2017年 | 18篇 |
2016年 | 27篇 |
2015年 | 15篇 |
2014年 | 28篇 |
2013年 | 29篇 |
2012年 | 42篇 |
2011年 | 47篇 |
2010年 | 43篇 |
2009年 | 25篇 |
2008年 | 46篇 |
2007年 | 40篇 |
2006年 | 38篇 |
2005年 | 43篇 |
2004年 | 46篇 |
2003年 | 49篇 |
2002年 | 57篇 |
2001年 | 30篇 |
2000年 | 36篇 |
1999年 | 28篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1992年 | 17篇 |
1991年 | 28篇 |
1990年 | 21篇 |
1989年 | 24篇 |
1988年 | 21篇 |
1987年 | 12篇 |
1986年 | 18篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1983年 | 18篇 |
1980年 | 6篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1976年 | 11篇 |
1975年 | 14篇 |
1974年 | 13篇 |
1973年 | 15篇 |
1972年 | 13篇 |
1971年 | 13篇 |
1970年 | 9篇 |
1969年 | 8篇 |
1968年 | 11篇 |
1967年 | 8篇 |
1966年 | 12篇 |
1965年 | 14篇 |
排序方式: 共有1144条查询结果,搜索用时 24 毫秒
1.
E M Nikulina O V Trapezov N K Popova 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1985,35(6):1142-1146
Content of dopamine in the striatum; of serotonin, 5-hydroxyindolacetic acid and noradrenaline in the hypothalamus, striatum and midbrain was studied in three groups of minks from population of an animal farm, differing by their reaction to humans (cowardly, calm, aggressive). The reaction to humans was estimated by a system of marks at the attempt to catch the mink with a mitten. Aggressive animals had a lowered level of serotonin in the hypothalamus and striatum, a lesser content of serotonin metabolite--5-hydroxyindolacetic acid in the striatum. Minks of different groups did not differ by noradrenaline content, but dopamine level in the striatum of cowardly minks was higher than in calm and aggressive animals. Conclusion is made that polymorphism of behaviour corresponds to polymorphism of the state of monoaminergic systems. 相似文献
2.
Antibacterial activity of Turkish propolis and its qualitative and quantitative chemical composition 总被引:7,自引:0,他引:7
The antibacterial activity of propolis from different regions of Turkey was studied, accompanied by TLC and GC-MS analyses of its chemical composition and spectrophotometric quantification of the most important active principles. All six samples were active against the bacterial test strains used; however, samples 1 (Yozgat), 2 (Izmir) and 3 (Kayseri) were more active than samples 4 (Adana), 5 (Erzurum) and 6 (Artvin). By TLC comparison all samples were found to contain poplar taxonomic markers but in samples 4 (Adana), 5 (Erzurum) and 6 (Artvin), different substances were observed, which were not present in P. nigra L. bud exudate. The typical poplar samples 1 (Yozgat), 2 (Izmir) and 3 (Kayseri) displayed very similar phenolic and flavonoid content. Samples 4 (Adana), 5 (Erzurum) and 6 (Artvin) were characterized by low phenolic and very low flavonoid concentrations. Qualitative analysis by GC-MS revealed that sample 4 (Adana) contained diterpenic acids and high percent of cinnamyl cinnamate, sample 5 (Erzurum)-significant amounts of hydroxy fatty acids and triterpenic alcohoLs, and sample 6 (Artvin)-phenolic glycerides, characteristic for the bud exudate of Populus euphratica Oliv. The results confirm the importance of phenolics for propolis antibacterial activity, and the significance of P. nigra L. as a propolis source, which provides the hive with the best defense against microorganisms. 相似文献
3.
4.
5.
6.
7.
8.
EA Dukhanina TI Lukyanova EA Romanova V Guerriero NV Gnuchev GP Georgiev DV Yashin LP Sashchenko 《Cell cycle (Georgetown, Tex.)》2015,14(22):3635-3643
PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4+ and CD8+ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response. 相似文献
9.
V I Popova L M Va?ner I I Gorshkova O A Gromova V V Liakhovich 《Biokhimii?a (Moscow, Russia)》1985,50(1):53-62
The previously described, iodine-labeled alkylating stable nitroxyl radicals located at different distances between the N-O. group and the iodine atom were used for a comparative study of the structure of microsomal cytochromes P-450 and P-448 active centers. The radicals were shown to change the optical spectra of Fe3+ located in the active site of the enzyme that are similar to those induced by cytochrome P-450 substrates. Some differences in the type of the radicals binding to control, phenobarbital- and 3-methylcholanthrene-induced microsomes were revealed. The alkylating radical substrate analogs covalently bound to microsomal cytochrome P-450 in the vicinity of the active center, resulting in the inhibition of oxidation of type I and II substrates (e. g., aniline and naphthalene). The value of the spectral binding constant (Ks) for naphthalene in the presence of the radical covalently bound to the cytochrome P-450 active center showed a tendency to increase. Using the ESR technique, the interaction between Fe3+ and the radical localized in the active site of cytochrome P-450 was demonstrated. The contribution of Fe3+ to the relaxation of the radicals covalently bound to cytochrome P-450 was evaluated from the values of the spin label ESR spectra saturation curves at 77K. The distances between the N-O. group of these radicals and Fe3+ in the enzyme active center for the three types of microsomes were determined. The data obtained point to structural peculiarities of the active center of cytochrome P-450, depending on the microsomal type. 相似文献
10.
A review of experimental data documenting that domestication of animals is associated with hereditary reorganization of neuro-endocrine mechanisms, responsible for basic processes of ontogeny, is presented. The data demonstrated changes in gonadal and pituitary-adrenal systems in domesticated animals. Analysis of evidence that selection for low aggressiveness towards man is, in fact, the selection for definite activity of brain neurotransmitters regulating aggressive behaviour and emotional stress response has been carried out. Supposed role of modifications in the mechanisms of domestication is discussed. 相似文献