全文获取类型
收费全文 | 490028篇 |
免费 | 53218篇 |
国内免费 | 204篇 |
专业分类
543450篇 |
出版年
2018年 | 4668篇 |
2016年 | 6471篇 |
2015年 | 8880篇 |
2014年 | 10410篇 |
2013年 | 14350篇 |
2012年 | 16644篇 |
2011年 | 17155篇 |
2010年 | 11723篇 |
2009年 | 10783篇 |
2008年 | 15594篇 |
2007年 | 16165篇 |
2006年 | 15252篇 |
2005年 | 14742篇 |
2004年 | 14840篇 |
2003年 | 13800篇 |
2002年 | 13597篇 |
2001年 | 18161篇 |
2000年 | 17972篇 |
1999年 | 14664篇 |
1998年 | 6010篇 |
1997年 | 6018篇 |
1996年 | 5595篇 |
1995年 | 5278篇 |
1994年 | 5118篇 |
1993年 | 5140篇 |
1992年 | 12136篇 |
1991年 | 12048篇 |
1990年 | 11795篇 |
1989年 | 11460篇 |
1988年 | 10958篇 |
1987年 | 10521篇 |
1986年 | 9759篇 |
1985年 | 9762篇 |
1984年 | 8409篇 |
1983年 | 7269篇 |
1982年 | 5835篇 |
1981年 | 5305篇 |
1980年 | 5090篇 |
1979年 | 7852篇 |
1978年 | 6339篇 |
1977年 | 5866篇 |
1976年 | 5672篇 |
1975年 | 5948篇 |
1974年 | 6752篇 |
1973年 | 6576篇 |
1972年 | 5997篇 |
1971年 | 5466篇 |
1970年 | 4882篇 |
1969年 | 4822篇 |
1968年 | 4620篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
171.
172.
173.
174.
175.
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
176.
A A Grinev E I Samokhvalov N A Petrov S K Vasilenko V P Iuferov 《Molekuliarnaia genetika, mikrobiologiia i virusologiia》1988,(9):43-45
The primary structure of hemagglutinin (HA) gene of Influenza virus A/USSR/90/77 (H1N1) variants after 3 and 11 passages has been determined. In the HA1 coding region of mice-adapted virus (11 passages) there are two amino acid substitutions: Thr 89----Ala and Asn 127----Asp. At the first stage of adaptation (3-rd passage) only a single mutation was detected: Asn 127----Asp. The adaptation is accompanied by the loss of specific carbohydrate attachment sites adjacent to the receptor-binding site located at HA1 subunit with a concomitant variation in antigenicity. 相似文献
177.
Bharat Lagu John M. Wetzel Carlos Forray Michael A. Patane Mark G. Bock 《Bioorganic & medicinal chemistry letters》2000,10(24)
The binding affinities and selectivities of antagonists Figure 1 and Scheme 2 for the α1A-adrenoceptor are dependent on the stereochemical orientation of the groups at the C-4 and C-5 positions of the oxazolidinone ring. The unambiguous assignment of the relative and absolute configurations of the diastereomers of SNAP 7915 (Figure 1 and Scheme 2) is reported. 相似文献
178.
179.
Evidence that the intestinal microbiota is intrinsically linked with overall health, including cancer risk, is emerging. Moreover, its composition is not fixed but can be influenced by several dietary components. Dietary modifiers, including the consumption of live bacteria (probiotics) and indigestible or limited digestible food constituents such as oligosaccharides (prebiotics) and polyphenols or both (synbiotics), are recognized modifiers of the numbers and types of microbes and have been reported to reduce colon cancer risk experimentally. Microorganisms also have the ability to generate bioactive compounds from food components. Examples include equol from isoflavones, enterodiol and enterolactone from lignans and urolithins from ellagic acid, which have also been demonstrated to retard experimentally induced cancers. The gastrointestinal microbiota can also influence both sides of the energy balance equation, namely, as a factor influencing energy utilization from the diet and as a factor that influences host genes that regulate energy expenditure and storage. Because of the link between obesity and cancer incidence and mortality, this complex complexion deserves greater attention. Overall, a dynamic interrelationship exists between the intestinal microbiota and colon cancer risk, which can be modified by dietary components and eating behaviors. 相似文献
180.