全文获取类型
收费全文 | 418942篇 |
免费 | 35634篇 |
国内免费 | 297篇 |
专业分类
454873篇 |
出版年
2018年 | 4877篇 |
2017年 | 4667篇 |
2016年 | 6090篇 |
2015年 | 6359篇 |
2014年 | 8134篇 |
2013年 | 11604篇 |
2012年 | 13173篇 |
2011年 | 14106篇 |
2010年 | 9706篇 |
2009年 | 8590篇 |
2008年 | 12427篇 |
2007年 | 12840篇 |
2006年 | 12263篇 |
2005年 | 11576篇 |
2004年 | 11468篇 |
2003年 | 11123篇 |
2002年 | 10977篇 |
2001年 | 18988篇 |
2000年 | 18845篇 |
1999年 | 14580篇 |
1998年 | 4462篇 |
1997年 | 4460篇 |
1996年 | 4288篇 |
1995年 | 3910篇 |
1994年 | 3814篇 |
1992年 | 11405篇 |
1991年 | 11319篇 |
1990年 | 11308篇 |
1989年 | 11097篇 |
1988年 | 10316篇 |
1987年 | 9704篇 |
1986年 | 8745篇 |
1985年 | 9267篇 |
1984年 | 7341篇 |
1983年 | 6225篇 |
1982年 | 4341篇 |
1981年 | 3912篇 |
1980年 | 3728篇 |
1979年 | 6792篇 |
1978年 | 5174篇 |
1977年 | 4781篇 |
1976年 | 4664篇 |
1975年 | 5475篇 |
1974年 | 5949篇 |
1973年 | 5965篇 |
1972年 | 5278篇 |
1971年 | 4966篇 |
1970年 | 4306篇 |
1969年 | 4092篇 |
1968年 | 3865篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
V. V. Neimorovets 《Entomological Review》2006,86(3):294-297
Trapezonotus dispar Stål, 1872 is subdivided into two subspecies, T. dispar dispar (Europe) and T. dispar breviceps Jakovlev, 1882 (= T. seductor Horváth, 1883) (Caucasus and Asia Minor). T. inglorius Vinokurov, 1990 is synonymized with T. desertus Sedienstücker, 1951. 相似文献
992.
G. S. C. BUSO Z. P. S. AMARAL R. P. V. BRONDANI M. E. FERREIRA 《Molecular ecology resources》2006,6(1):252-254
Efforts to develop molecular tools for genetic analysis and breeding of common bean in the tropics are still limited. The number of microsatellite markers available for the crop is small compared to other crops of similar social and economic importance. As part of a project to broaden the use of molecular tools in bean breeding, a genomic library enriched for AG/TC repeat sequences was constructed for Phaseolus vulgaris. Twenty microsatellite markers were initially developed and 10 were characterized using a panel of 85 representative accessions of the bean gene bank. The number of alleles per marker ranged from three to 10. The polymorphism information content (PIC) varied from 0.23 to 0.80. The results indicate that the new markers can be readily used in genetically analysis of common bean. 相似文献
993.
994.
995.
V A Dobrykh 《Fiziologiia cheloveka》1987,13(6):1035-1037
996.
997.
998.
The alteration of hepatic drug-metabolizing enzyme activities in mice given Salmonella endotoxin by single or multiple intraperitoneal injections was investigated. An essentially the same biphasic, early and late phase, endotoxin tolerance was observed in the animals receiving a single injection of endotoxin or repetitive daily injections. The results of reciprocal cross tolerance tests using lipopolysaccharide and free lipid A preparations derived from Salmonella minnesota, Salmonella typhimurium, E. coli, Pseudomonas aeruginosa, and Chromobacterium violaceum suggested that lipid A moiety plays an important role in the induction of early endotoxin tolerance to endotoxin response. 相似文献
999.
R Kh Iafaev V V Dudareva T G Ivanova E B Kaganer L V Loseva 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1986,(11):16-20
The short-term prognosis of the epidemic situation requires the establishment of the system of constant surveillance, which takes into account the data on morbidity rates for several years, both total and in various age groups, the data on the morbidity level and its changes, induced by meningococci of the epidemic group, in the IV quarter of the year, the data on the level of carriership among the indicator groups of the population in this period, as well as the data on changes in antibody titers in the sera of donor blood samples taken in summer and in December. 相似文献
1000.
A. V. Shakhbazau G. A. Yakovleva I. A. Rod’kina N. A. Kartel 《Cytology and Genetics》2008,42(2):75-80
The pleiotropic effects of transgenesis includes different consequences of the insertion of a transgene that are not related to the direct action of its product. It is necessary to evaluate the outlook for the application in selection of the transgenic potato strain containing the bacterial chitinase gene chiA we created for studying the possible nonspecific influence of the introduction of the transgene on the phenotypical properties of the transgenic lines. In the present investigation we will consider the effect of the introduction of the chitinase transgene on such agronomically important characteristics as yield and nonspecific resistance. 相似文献