全文获取类型
收费全文 | 272734篇 |
免费 | 14590篇 |
国内免费 | 933篇 |
专业分类
288257篇 |
出版年
2018年 | 13458篇 |
2017年 | 12256篇 |
2016年 | 9574篇 |
2015年 | 2710篇 |
2014年 | 3200篇 |
2013年 | 4467篇 |
2012年 | 8936篇 |
2011年 | 17910篇 |
2010年 | 15493篇 |
2009年 | 11417篇 |
2008年 | 14473篇 |
2007年 | 16296篇 |
2006年 | 5066篇 |
2005年 | 5017篇 |
2004年 | 5618篇 |
2003年 | 5588篇 |
2002年 | 5328篇 |
2001年 | 8626篇 |
2000年 | 8730篇 |
1999年 | 6333篇 |
1998年 | 1996篇 |
1997年 | 2056篇 |
1996年 | 1810篇 |
1993年 | 1701篇 |
1992年 | 5218篇 |
1991年 | 5401篇 |
1990年 | 5145篇 |
1989年 | 5123篇 |
1988年 | 4749篇 |
1987年 | 4498篇 |
1986年 | 4076篇 |
1985年 | 4234篇 |
1984年 | 3415篇 |
1983年 | 2929篇 |
1982年 | 1931篇 |
1981年 | 1728篇 |
1980年 | 1719篇 |
1979年 | 3211篇 |
1978年 | 2545篇 |
1977年 | 2279篇 |
1976年 | 2082篇 |
1975年 | 2551篇 |
1974年 | 2884篇 |
1973年 | 2802篇 |
1972年 | 2894篇 |
1971年 | 2684篇 |
1970年 | 2123篇 |
1969年 | 2022篇 |
1968年 | 1906篇 |
1967年 | 1743篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
I N Blokhina V M Lavrovskaia R Sh Al'tman 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1978,(7):112-115
The authors prepared under experimental-industrial conditions paper indicator systems for the express identification of microbes, including carbohydrate discs (by the method of Nikitin et al.), and newly worked out types for the determination of the activity of cytochromoxidase, urease, indol formation, and indicator amino acid decarboxylases (lysin, ornithin, arginine). The use of paper indicator discs proved to be expedient for rationalization of laboratory diagnosis of bacterial intestinal infections. 相似文献
902.
903.
The voltage-sensitive Na+ channel is responsible for the action potential of membrane electrical excitability in neuronal tissue. Three methods were used to demonstrate the presence of neurotoxin-responsive Na+ channels in two hybrid cell lines resulting from the fusion of excitable human neuroblastoma cells with mouse fibroblasts. Only one of the two electrically active hybrid cell lines maintained the sensitivity of the neuroblastoma parent to tetrodotoxin (TTX). The other hybrid, although electrically active, was not responsive to TTX or scorpion venom. Comparisons of the patterns of expression of membrane excitability and of chromosome complements in these human neuroblastoma cell hybrids suggest that the phenotype of membrane excitability is composed of genetically distinct elements. 相似文献
904.
Interaction of heat-denatured HeLa cell DNA with synthetic and natural polysaccharides 总被引:2,自引:0,他引:2
I L Graves 《Biopolymers》1968,6(11):1573-1578
Heat-denatured DNA from HeLa cells interacts with natural as well as synthetic polysaccharides. Glucose does not inhibit the interaction nor will it produce it. Polysaccharides with a molecular weight of 10000 or greater are required before the interaction takes place. 相似文献
905.
906.
TheSRM12/ADA1 gene sequence inserted into a recombinant circular plasmid improves its maintenance in budding yeast (Saccharomyces cerevisiae) cells. Plasmid stabilization caused by the integrated SRM12 sequence does not require the SRM12 function complementing the srm12 mutation and depends on the orientation of the inserted sequence in the vector. This stabilization is mainly due to a decrease in spontaneous plasmid underreplication/copy loss rather than an increase in the fidelity of mitotic plasmid segregation. 相似文献
907.
908.
Iu A Belaia V M Bondarenko V G Petrukhin I E Deev 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1982,(8):38-42
Genetic and immunoelectrophoretic studies confirm earlier data on the presence of 2 specific antigens of acidic nature in S. newcastle; one of them is a specific thermolabile K-antigen responsible for type IV specificity of these bacteria. The data concerning the differences in the genetic determinants controlling the synthesis of O- and K-antigens in S. newcastle have been obtained. S. newcastle O- and K-antigens did not react with S. flexneri in the group serum system 3, 4, which indicates that S. newcastle are serologically isolated and form a separate taxonomic group of dysentery bacteria. The existence of cross reactions between S. flexneri and S. newcastle due to the presence of neutral R-core antigens common to these 2 species has been shown . Immunoelectrophoresis in agar is the most promising and informative method in genetic and chemical studies of the antigenic structure of bacteria. 相似文献
909.
I Urasiński G Uhlenbruck C Dienst 《Folia haematologica (Leipzig, Germany : 1928)》1985,112(3):403-408
The capacity to phagocytosis in monocytic macrophages was investigated in 24 patients with plasmocytoma. The investigation of this capacity was made by using short-term cultures with sheep erythrocytes loaded with antibodies and complement. In comparison to the control group the percentage of phagocyting macrophages was lowered in 16 from 24 patients. This impairment of the function of monocytic macrophages seems to be bound neither to the type of plasmocytoma nor to the stage of disease. Among other things, the nature of cell defect is discussed. The necessity of further investigations is emphasized. 相似文献
910.