全文获取类型
收费全文 | 502278篇 |
免费 | 53960篇 |
国内免费 | 394篇 |
出版年
2018年 | 4657篇 |
2016年 | 6056篇 |
2015年 | 7337篇 |
2014年 | 8978篇 |
2013年 | 12619篇 |
2012年 | 14064篇 |
2011年 | 14819篇 |
2010年 | 9923篇 |
2009年 | 9228篇 |
2008年 | 13102篇 |
2007年 | 13465篇 |
2006年 | 13039篇 |
2005年 | 12507篇 |
2004年 | 12282篇 |
2003年 | 11995篇 |
2002年 | 11720篇 |
2001年 | 26444篇 |
2000年 | 26627篇 |
1999年 | 20390篇 |
1998年 | 6154篇 |
1997年 | 6460篇 |
1996年 | 6129篇 |
1995年 | 5589篇 |
1994年 | 5527篇 |
1993年 | 5514篇 |
1992年 | 16177篇 |
1991年 | 15987篇 |
1990年 | 15547篇 |
1989年 | 15247篇 |
1988年 | 14255篇 |
1987年 | 13369篇 |
1986年 | 12065篇 |
1985年 | 12184篇 |
1984年 | 9628篇 |
1983年 | 8419篇 |
1982年 | 5965篇 |
1981年 | 5391篇 |
1980年 | 5086篇 |
1979年 | 8909篇 |
1978年 | 6872篇 |
1977年 | 6309篇 |
1976年 | 5849篇 |
1975年 | 6692篇 |
1974年 | 7136篇 |
1973年 | 7064篇 |
1972年 | 6203篇 |
1971年 | 5786篇 |
1970年 | 5143篇 |
1969年 | 4831篇 |
1968年 | 4438篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
211.
212.
Microsatellite DNA in peach (Prunus persica L. Batsch) and its use in fingerprinting and testing the genetic origin of cultivars. 总被引:11,自引:0,他引:11
R Testolin T Marrazzo G Cipriani R Quarta I Verde M T Dettori M Pancaldi S Sansavini 《Génome》2000,43(3):512-520
We isolated and sequenced 26 microsatellites from two genomic libraries of peach cultivar 'Redhaven', enriched for AC/GT and AG/CT repeats, respectively. For 17 of these microsatellites, it was possible to demonstrate Mendelian inheritance. Microsatellite polymorphism was assayed in 50 peach and nectarine cultivars. Of the 1300 PCRs carried out, all but two produced amplified products of the expected size. All microsatellites were polymorphic, showing 2-8 alleles per locus. Heterozygosity ranged from 0.04-0.74 (mean 0.47); the discrimination power (PD) ranged from 0.04-0.84 (mean 0.60). Cultivar heterozygosity varied greatly, with one cultivar ('Independence') being homozygous at all loci. The set of microsatellites discriminated all cultivars investigated, except several sport mutations, i.e., 'Dixitime' vs. 'Springcrest', 'Compact Redhaven' vs. 'Redhaven', and two pairs of cultivars, 'Venus' vs. 'Orion' and 'Elegant Lady' vs. 'Rome Star', whose pedigrees are controversial. We were able to analyze the paternity of several cultivars. In most cases, the parenthood was confirmed. The comparison of three long-living 'Redhaven' accessions supplied by different repositories did not provide any evidence of somatic instability of microsatellites. Hence, microsatellites, ranked according to their information content, are recommended as markers of choice for peach fingerprinting and suggestions are provided for interpreting band profiles and the correct sizing of alleles. 相似文献
213.
Ia I Serkiz A I Lipskaia L B Pinchuk V V Trishin Iu F Kataevski? G N Koval' 《Radiobiologiia》1991,31(5):629-634
Irradiation conditions in which laboratory animals were kept in experimental laboratories of Chernobyl and Kiev after the accident at the Chernobyl A.P.S. are described. The data are presented on the spectral structural and activity of radionuclides in the diet as well as in the organs and tissues of the animals. The radiation loads have been estimated with regard to an external gamma component and the internal one contributed by the incorporated radionuclides. It has been shown that radiation doses received by the animals during their lifetime due to these contributions do not exceed units of cGy. 相似文献
214.
215.
216.
E T Iwamoto 《Life sciences》1988,43(6):503-508
Intracerebroventricular (i.c.v.) administration of dynorphin A [1-17] induced significant place preference conditioning in male, Sprague-Dawley rats. Place preferences were induced by 2.3 and 3.5 nmole, but not 1.2 nmole of dynorphin A. Co-administration of naloxone, 27.5 nmole but not 5.5 nmole, antagonized the reward response induced by 2.3 nmole of dynorphin A. Leu-enkephalin, 5 or 25 nmole, and dynorphin A [2-17], 2.3 or 3.5 nmole, had no effect in the place conditioning paradigm. 相似文献
217.
N B Terenina 《Parazitologiia》1988,22(6):476-480
Identification of serotonin and dopamine in M. salmonis was conducted by means of some fluorometric methods. The presence of negligible amount of a serotonin-like component and substance close in its spectral characteristics to dopamine was shown. 相似文献
218.
E A Rybnikova V G Shaliapina O N Zamuruev 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1999,49(1):77-83
The effects of corticotropin-releasing hormone (CRH) injected into the dorsal neostriatum on the open-field and shuttle-box behavior were studied in rats with high (Koltushi high avoidance, KHA) and low (Koltushi low avoidance, KLA) capability for avoidance learning. The effects of this hormone on the behavior of these rat strains were different. In KLA rats with passive strategy of behavior the CRH injection led to a rapid locomotor activation in the open field, while the rats with active behavioral strategy (KHA) reacted to the injection by a significant decrease in locomotion and change for the passive mode of behavior. The same CRH effects on locomotion were obtained in the shuttle-box experiments. Moreover, in the KLA rats the neurohormone injection resulted in an improvement of avoidance learning in contrast to the KHA rats, in which CRH substantially impaired avoidance learning. The obtained evidence is discussed in terms of the important role of striatal CRH in the choice of behavioral strategy in stress. 相似文献
219.
220.