全文获取类型
收费全文 | 868037篇 |
免费 | 103350篇 |
国内免费 | 887篇 |
出版年
2018年 | 7391篇 |
2016年 | 10031篇 |
2015年 | 14396篇 |
2014年 | 16968篇 |
2013年 | 23649篇 |
2012年 | 26933篇 |
2011年 | 27437篇 |
2010年 | 18294篇 |
2009年 | 16936篇 |
2008年 | 24396篇 |
2007年 | 25439篇 |
2006年 | 23867篇 |
2005年 | 22964篇 |
2004年 | 22886篇 |
2003年 | 21805篇 |
2002年 | 21049篇 |
2001年 | 35968篇 |
2000年 | 36274篇 |
1999年 | 29169篇 |
1998年 | 11018篇 |
1997年 | 11256篇 |
1996年 | 10756篇 |
1995年 | 10334篇 |
1994年 | 10024篇 |
1993年 | 10036篇 |
1992年 | 25079篇 |
1991年 | 24866篇 |
1990年 | 24437篇 |
1989年 | 23712篇 |
1988年 | 22127篇 |
1987年 | 21145篇 |
1986年 | 19928篇 |
1985年 | 20047篇 |
1984年 | 16773篇 |
1983年 | 14699篇 |
1982年 | 11233篇 |
1981年 | 10516篇 |
1980年 | 9791篇 |
1979年 | 16292篇 |
1978年 | 12997篇 |
1977年 | 11760篇 |
1976年 | 11154篇 |
1975年 | 12582篇 |
1974年 | 13433篇 |
1973年 | 13049篇 |
1972年 | 12095篇 |
1971年 | 10872篇 |
1970年 | 9365篇 |
1969年 | 8992篇 |
1968年 | 8217篇 |
排序方式: 共有10000条查询结果,搜索用时 734 毫秒
931.
932.
933.
934.
V. v. Borbás P. L. Wiedermann Franz Hüfer E. Hackel 《Plant Systematics and Evolution》1890,40(11):427-428
Ohne Zusammenfassung 相似文献
935.
Treatment of cut-throat trout broodfish Salmo clarki (Richardson) with Sulphamerazine at 220 mg/kg (10 g/100 1b) of fish/day for 14 days resulted in severe kidney histopathology and increased mortality among males. Experimental data presented showed that cut-throat trout broodfish were extremely sensitive to Sulphamerazine toxicity. Hydropic degeneration of renal tubule epithelium and haemorrhage into tubule lumens were observed in kidneys of both male and female trout, but was more severe in the former. Death, which occurred only in males, was correlated with spawning stress and impaired renal function. 相似文献
936.
937.
938.
Brunner RM Srikanchai T Murani E Wimmers K Ponsuksili S 《Molecular biology reports》2012,39(1):97-107
Six genes that were known to exhibit expression levels that are correlated to drip loss BVES, SLC3A2, ZDHHC5, CS, COQ9, and
EGFR have been for candidate gene analysis. Based on in silico analysis SNPs were detected, confirmed by sequencing, and used for genotyping. The SNPs were genotyped in about 1,800 animals
from six pig populations including commercial herds of Pietrain (PI) and German Landrace (DL), different commercial herds
of Pietrain × (German Large White × German Landrace) (PIF1(a/b/c)), and one experimental F2-population Duroc × Pietrain (DUPI). Comparative and genetic mapping established the location of BVES on SSC1, of SLC3A2 and
ZDHHC5 on SSC2, of CS on SSC5, of COQ9 on SSC6 and of EGFR on SSC9, respectively, coinciding with QTL regions for carcass
and meat quality traits. BVES, SLC3A2, and CS revealed association at least with drip loss and with several other measures
of water holding capacity (WHC). Moreover, COQ9 and EGFR were associated with several meat quality traits such as meat color
and/or thawing loss. This study reveals statistic evidence in addition to the functional relationship of these genes to WHC
previously evidenced by expression analysis. This study reveals positional and genetic statistical evidence for a link of
genetic variation at these loci or close to them and promotes those six candidate genes as functional and/or positional candidate
genes for meat quality traits. 相似文献
939.
A. Gumbert J. Kunze L. Chittka 《Proceedings. Biological sciences / The Royal Society》1999,266(1429):1711
Evolutionary biologists have long hypothesized that the diversity of flower colours we see is in part a strategy to promote memorization by pollinators, pollinator constancy, and therefore, a directed and efficient pollen transfer between plants. However, this hypothesis has never been tested against a biologically realistic null model, nor were colours assessed in the way pollinators see them. Our intent here is to fill these gaps. Throughout one year, we sampled floral species compositions at five ecologically distinct sites near Berlin, Germany. Bee-subjective colours were quantified for all 168 species. A model of colour vision was used to predict how similar the colours of sympatric and simultaneously blooming flowers were for bees. We then compared flower colour differences in the real habitats with those of random plant communities. We did not find pronounced deviations from chance when we considered common plants. When we examined rare plants, however, we found significant divergence in two of the five plant communities. At one site, similarly coloured species were found to be more frequent than expected, and at the other two locations, flower colours were indistinguishable from a random distribution. These results fit theoretical considerations that rare plants are under stronger selective pressure to secure pollination than common plants. Our study illustrates the power of linking such distinct biological traditions as community ecology and the neuroethology of bee vision. 相似文献
940.