全文获取类型
| 收费全文 | 1162篇 |
| 免费 | 62篇 |
专业分类
| 林业 | 27篇 |
| 农学 | 15篇 |
| 基础科学 | 14篇 |
| 118篇 | |
| 综合类 | 157篇 |
| 农作物 | 39篇 |
| 水产渔业 | 46篇 |
| 畜牧兽医 | 760篇 |
| 园艺 | 14篇 |
| 植物保护 | 34篇 |
出版年
| 2020年 | 13篇 |
| 2019年 | 18篇 |
| 2018年 | 11篇 |
| 2017年 | 18篇 |
| 2016年 | 21篇 |
| 2015年 | 17篇 |
| 2014年 | 8篇 |
| 2013年 | 81篇 |
| 2012年 | 50篇 |
| 2011年 | 47篇 |
| 2010年 | 32篇 |
| 2009年 | 17篇 |
| 2008年 | 47篇 |
| 2007年 | 58篇 |
| 2006年 | 33篇 |
| 2005年 | 41篇 |
| 2004年 | 45篇 |
| 2003年 | 28篇 |
| 2002年 | 35篇 |
| 2001年 | 30篇 |
| 2000年 | 37篇 |
| 1999年 | 22篇 |
| 1998年 | 14篇 |
| 1997年 | 21篇 |
| 1996年 | 18篇 |
| 1995年 | 19篇 |
| 1994年 | 12篇 |
| 1993年 | 10篇 |
| 1992年 | 29篇 |
| 1991年 | 24篇 |
| 1990年 | 29篇 |
| 1989年 | 17篇 |
| 1988年 | 32篇 |
| 1987年 | 31篇 |
| 1986年 | 17篇 |
| 1985年 | 21篇 |
| 1984年 | 8篇 |
| 1983年 | 10篇 |
| 1981年 | 8篇 |
| 1979年 | 15篇 |
| 1978年 | 15篇 |
| 1977年 | 9篇 |
| 1975年 | 9篇 |
| 1973年 | 10篇 |
| 1972年 | 12篇 |
| 1971年 | 15篇 |
| 1970年 | 8篇 |
| 1969年 | 10篇 |
| 1967年 | 12篇 |
| 1965年 | 8篇 |
排序方式： 共有1224条查询结果，搜索用时 15 毫秒
101.
Genes, genetics, and epigenetics: a correspondence 总被引：2，自引：0，他引：2
Over the past months, as this special issue took shape, the Editors of Science have monitored an exchange of seven letters initiated by three queries from M. Bacon. These queries concern the popular definitions of "genes," "genetics," and "epigenetics." Below, we reprint excerpts from these letters, referring interested readers to www.sciencemag.org/cgi/content/full/293/5532/1103/DC1 for the complete text and additional references. 相似文献
102.
Soft-bodied and lightly sclerotized Burgess shale fossils have been found at more than a dozen new localities in an area extending for 20 kilometers along the front of the Cathedral Escarpment in the Middle Cambrian Stephen Formation of the Canadian Rockies. Five different fossil assemblages from four stratigraphic levels have been recognized. These assemblages represent distinct penecontemporaneous marine communities that together make up a normal fore-reef faunal complex. 相似文献
103.
104.
Four Paleozoic bivalved genera are assigned to the new molluscan class Rostroconchia: Eopteria, Euchasma, Conocardium, and Pseudoconocardium. These mollusks have ani uncoiled univalved larval shell; an untorted bivalved adult shell; no hinge teeth, ligament, or adductor muscles; and a fused, almost inflexible. hinge. Rostroconchianis developed separately from the pelecypods through the ribeirioids, but are regarded as more closely related to the Pelecypoda and Scaphopoda than to other known classes of mollusks. 相似文献
105.
106.
107.
Humans, but no other animal, make meaningful use of spoken language. What is unclear, however, is whether this capacity depends on a unique constellation of perceptual and neurobiological mechanisms or whether a subset of such mechanisms is shared with other organisms. To explore this problem, parallel experiments were conducted on human newborns and cotton-top tamarin monkeys to assess their ability to discriminate unfamiliar languages. A habituation-dishabituation procedure was used to show that human newborns and tamarins can discriminate sentences from Dutch and Japanese but not if the sentences are played backward. Moreover, the cues for discrimination are not present in backward speech. This suggests that the human newborns' tuning to certain properties of speech relies on general processes of the primate auditory system. 相似文献
108.
109.
110.
Sundareshwar PV Murtugudde R Srinivasan G Singh S Ramesh KJ Ramesh R Verma SB Agarwal D Baldocchi D Baru CK Baruah KK Chowdhury GR Dadhwal VK Dutt CB Fuentes J Gupta PK Hargrove WW Howard M Jha CS Lal S Michener WK Mitra AP Morris JT Myneni RR Naja M Nemani R Purvaja R Raha S Vanan SK Sharma M Subramaniam A Sukumar R Twilley RR Zimmerman PR 《Science (New York, N.Y.)》2007,316(5822):204-205