全文获取类型
收费全文 | 1818篇 |
免费 | 112篇 |
国内免费 | 1篇 |
专业分类
林业 | 56篇 |
农学 | 16篇 |
基础科学 | 10篇 |
119篇 | |
综合类 | 550篇 |
农作物 | 69篇 |
水产渔业 | 160篇 |
畜牧兽医 | 868篇 |
园艺 | 21篇 |
植物保护 | 62篇 |
出版年
2021年 | 21篇 |
2020年 | 26篇 |
2019年 | 46篇 |
2018年 | 32篇 |
2017年 | 49篇 |
2016年 | 21篇 |
2015年 | 23篇 |
2014年 | 27篇 |
2013年 | 72篇 |
2012年 | 50篇 |
2011年 | 78篇 |
2010年 | 31篇 |
2009年 | 33篇 |
2008年 | 79篇 |
2007年 | 74篇 |
2006年 | 55篇 |
2005年 | 40篇 |
2004年 | 61篇 |
2003年 | 41篇 |
2002年 | 46篇 |
2001年 | 35篇 |
2000年 | 36篇 |
1999年 | 38篇 |
1998年 | 16篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1992年 | 33篇 |
1991年 | 33篇 |
1990年 | 36篇 |
1989年 | 22篇 |
1988年 | 29篇 |
1987年 | 30篇 |
1986年 | 33篇 |
1985年 | 22篇 |
1984年 | 15篇 |
1983年 | 20篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1975年 | 16篇 |
1974年 | 20篇 |
1973年 | 30篇 |
1972年 | 15篇 |
1970年 | 21篇 |
1969年 | 17篇 |
1968年 | 22篇 |
1901年 | 19篇 |
1898年 | 14篇 |
1897年 | 24篇 |
1896年 | 22篇 |
1895年 | 26篇 |
排序方式: 共有1931条查询结果,搜索用时 15 毫秒
991.
When 2 micrograms of antinomycin D was injected intracranially into goldfish immediately after a training session, the formation of long-term memory of a shock-avoidance was blocked. The results are discussed in relation to similar findings with acetoxycycloheximide and puromycin in the goldfish and with apparently conflicting results in the mouse. 相似文献
992.
993.
994.
995.
996.
The termination of a solid induces changes in the locations of the outermost atoms of the solid. The changes can be minor or as dramatic as the rearrangement of the atoms into a different crystallographic group. Surface crystallography studies have determined that all surfaces are altered by forces induced at the solid-vacuum interface. At the least, the outermost atomic layers are displaced away from positions that they would have had in the bulk environment. Results from experimental and theoretical investigations for the Al(110) surface are discussed to illustrate present understanding of the surface atomic displacements. Some effects that the truncation- induced forces have on the surfaces of binary metal alloys are also discussed. 相似文献
997.
998.
Whalen PJ Kagan J Cook RG Davis FC Kim H Polis S McLaren DG Somerville LH McLean AA Maxwell JS Johnstone T 《Science (New York, N.Y.)》2004,306(5704):2061
The amygdala was more responsive to fearful (larger) eye whites than to happy (smaller) eye whites presented in a masking paradigm that mitigated subjects' awareness of their presence and aberrant nature. These data demonstrate that the amygdala is responsive to elements of. 相似文献
999.
Polysomes extracted from Escherichia coli by freeze-thaw-lysozyme lysis 总被引:34,自引:0,他引:34
Polysomes can be extracted from Escherichia coli by freezing and thawing in the presence of lysozyme, followed by treatment with sodium deoxycholate. The method is simple and convenient; the yields consistently high. 相似文献
1000.
Teratogenicity of vitamin B6 deficiency: omphalocele, skeletal and neural defects, and splenic hypoplasia 总被引:1,自引:0,他引:1
Vitamin B(6) deficiency was induced in pregnant rats with a deficient diet and with 4-deoxypyridoxine, a B(6) antagonist. Treated animals developed typical skin changes of B(6) deficiency. Fetuses were small and appeared anemic. Major fetal malformations were omphalocele, exencephaly, cleft palate, micrognathia, digital defects, and splenic hypoplasia. This teratologic system was developed as a model for human syndromes that exhibit combined immunologic and neurologic or skeletal defects. 相似文献