全文获取类型
收费全文 | 35788篇 |
免费 | 3066篇 |
国内免费 | 19篇 |
出版年
2023年 | 113篇 |
2022年 | 319篇 |
2021年 | 593篇 |
2020年 | 360篇 |
2019年 | 479篇 |
2018年 | 599篇 |
2017年 | 526篇 |
2016年 | 927篇 |
2015年 | 1567篇 |
2014年 | 1698篇 |
2013年 | 2080篇 |
2012年 | 2808篇 |
2011年 | 2871篇 |
2010年 | 1787篇 |
2009年 | 1678篇 |
2008年 | 2360篇 |
2007年 | 2421篇 |
2006年 | 2260篇 |
2005年 | 2106篇 |
2004年 | 2084篇 |
2003年 | 1930篇 |
2002年 | 1875篇 |
2001年 | 419篇 |
2000年 | 278篇 |
1999年 | 413篇 |
1998年 | 477篇 |
1997年 | 341篇 |
1996年 | 308篇 |
1995年 | 275篇 |
1994年 | 240篇 |
1993年 | 257篇 |
1992年 | 231篇 |
1991年 | 175篇 |
1990年 | 158篇 |
1989年 | 179篇 |
1988年 | 139篇 |
1987年 | 128篇 |
1986年 | 103篇 |
1985年 | 139篇 |
1984年 | 163篇 |
1983年 | 111篇 |
1982年 | 127篇 |
1981年 | 116篇 |
1980年 | 97篇 |
1979年 | 57篇 |
1978年 | 73篇 |
1977年 | 66篇 |
1976年 | 44篇 |
1974年 | 36篇 |
1973年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Gemma L. Moir-Meyer John F. Pearson Felicity Lose Rodney J. Scott Mark McEvoy John Attia Elizabeth G. Holliday Paul D. Pharoah Alison M. Dunning Deborah J. Thompson Douglas F. Easton Amanda B. Spurdle Logan C. Walker The Australian National Endometrial Cancer Study Group The Hunter Community Study Studies of Epidemiology Risk Factors in Cancer Heredity 《Human genetics》2015,134(3):269-278
52.
Striking difference in response to expanding brood parasites by birds in western and eastern Beringia
下载免费PDF全文
![点击此处可从《Journal of Field Ornithology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Vladimir Dinets Kristaps Sokolovskis Daniel Hanley Mark E. Hauber 《Journal of Field Ornithology》2018,89(2):117-125
Two species of obligate brood‐parasitic Cuculus cuckoos are expanding their ranges in Beringia. Both now breed on the Asian side, close to the Bering Strait, and are found in Alaska during the breeding season. From May to July 2017, we used painted 3D‐printed model eggs of two cuckoo host‐races breeding in northeastern Siberia to test behavioral responses of native songbirds on both sides of the Bering Strait, with particular attention to species that are known cuckoo hosts in their Siberian range. Each host nest was tested after the second egg was laid and, if possible, again 4 days later with a model of a different type. Although our Siberian study site was also outside the known breeding ranges of the cuckoos, we found that Siberian birds had strong anti‐parasite responses, with 14 of 22 models rejected. In contrast, birds in Alaska had virtually no detectable anti‐parasite behaviors, with only one of 96 models rejected; the rejecters were Red‐throated Pipits (Anthus cervinus). Such differences suggest that the cuckoos might successfully parasitize naïve hosts and become established in North America whether or not their historic host species are widely available. 相似文献
53.
54.
Mark Houston 《New Zealand journal of zoology.》2013,40(4):241-243
Abstract Agriculture is fundamental to the well being of the New Zealand economy. We are very much a trading nation and will continue, for the foreseeable future, to depend upon primary production for the generation of New Zealand's wealth. 相似文献
55.
56.
Xu Zhang Wei Zhang Santosh L. Saraf Mehdi Nouraie Jin Han Michel Gowhari Johara Hassan Galina Miasnikova Adelina Sergueeva Sergei Nekhai Rick Kittles Roberto F. Machado Joe G. N. Garcia Mark T. Gladwin Martin H. Steinberg Paola Sebastiani Donald A. McClain Victor R. Gordeuk 《Human genetics》2015,134(8):895-904
57.
58.
59.
Marion S. R?der Mark E. Sorrells Steven D. Tanksley 《Molecular & general genetics : MGG》1992,232(2):215-220
Summary The long-range structure of 5S rRNA gene clusters has been investigated in wheat (Triticum aestivum L.) by means of pulsed field gel electrophoresis. Using aneuploid stocks, 5S rRNA gene clusters were assigned to sites on chromosomes 1B, 1D, 513 and 5D. Cluster sizes were evaluated and the copy number of 5S DNA repeats was estimated at 4700-5200 copies for the short repeating unit (410 bp) and about 3100 copies for the long repeat (500 bp) per haploid genome. A comparison of wheat cultivars revealed extremely high levels of polymorphism in the 5S rRNA gene clusters. With one restriction enzyme digest all varieties tested gave unique banding patterns and, on a per fragment basis, 21-fold more polymorphism was detected among cultivars for 5S DNA compared to standard restriction fragment length polymorphisms (RFLPs) detected with single copy clones. Experiments with aneuploid stocks suggest that the 5S rRNA gene clusters at several chromosomal sites contribute to this polymorphism. A number of previous reports have shown that wheat cultivars are not easily distinguished by isozymes or RFLPs. The high level of variation detected in 5S rRNA gene clusters therefore offers the possibility of a sensitive fingerprinting method for wheat. 5S DNA and other macro-satellite sequences may also serve as hypervariable Mendelian markers for genetic and breeding experiments in wheat. 相似文献
60.