全文获取类型
收费全文 | 1266篇 |
免费 | 88篇 |
国内免费 | 1篇 |
专业分类
林业 | 80篇 |
农学 | 24篇 |
基础科学 | 4篇 |
196篇 | |
综合类 | 217篇 |
农作物 | 55篇 |
水产渔业 | 112篇 |
畜牧兽医 | 553篇 |
园艺 | 27篇 |
植物保护 | 87篇 |
出版年
2023年 | 16篇 |
2022年 | 15篇 |
2021年 | 27篇 |
2020年 | 40篇 |
2019年 | 34篇 |
2018年 | 34篇 |
2017年 | 29篇 |
2016年 | 34篇 |
2015年 | 22篇 |
2014年 | 25篇 |
2013年 | 48篇 |
2012年 | 72篇 |
2011年 | 86篇 |
2010年 | 48篇 |
2009年 | 41篇 |
2008年 | 80篇 |
2007年 | 91篇 |
2006年 | 52篇 |
2005年 | 73篇 |
2004年 | 66篇 |
2003年 | 58篇 |
2002年 | 80篇 |
2001年 | 31篇 |
2000年 | 18篇 |
1999年 | 9篇 |
1998年 | 16篇 |
1997年 | 8篇 |
1996年 | 15篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1992年 | 8篇 |
1991年 | 19篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 14篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 13篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1971年 | 4篇 |
1943年 | 3篇 |
1933年 | 3篇 |
1931年 | 3篇 |
排序方式: 共有1355条查询结果,搜索用时 15 毫秒
101.
Anesthesia of Artemia larvae: method for quantitative study 总被引:2,自引:0,他引:2
A B Robinson K F Manly M P Anthony J F Catchpool L Pauling 《Science (New York, N.Y.)》1965,149(689):1255-1258
Potency of anesthetics is quantitatively measured with laboratory-hatched larvae of the brine shrimp Artemia salina. Statistical fluctuations are minimized in that 100,000 animals are used to determine a single median anesthetic dose value. The technique was developed to study molecular mechanisms of general anesthesia. 相似文献
102.
Selective sparing of a class of striatal neurons in Huntington's disease 总被引:29,自引:0,他引:29
R J Ferrante N W Kowall M F Beal E P Richardson E D Bird J B Martin 《Science (New York, N.Y.)》1985,230(4725):561-563
A distinct subpopulation of striatal aspiny neurons, containing the enzyme nicotinamide adenine dinucleotide phosphate diaphorase, is preserved in the caudate nucleus in Huntington's disease. Biochemical assays confirmed a significant increase in the activity of this enzyme in both the caudate nucleus and putamen in postmortem brain tissue from patients with this disease. The resistance of these neurons suggests that the gene defect in Huntington's disease may be modifiable by the local biochemical environment. This finding may provide insight into the nature of the genetically programmed cell death that is a characteristic of the disease. 相似文献
103.
Rett syndrome is an autism spectrum disorder caused by mosaic expression of mutant copies of the X-linked MECP2 gene in neurons. However, neurons do not die, which suggests that this is not a neurodegenerative disorder. An important question for future therapeutic approaches to this and related disorders concerns phenotypic reversibility. Can viable but defective neurons be repaired, or is the damage done during development without normal MeCP2 irrevocable? Using a mouse model, we demonstrate robust phenotypic reversal, as activation of MeCP2 expression leads to striking loss of advanced neurological symptoms in both immature and mature adult animals. 相似文献
104.
105.
106.
The Gilbert Ridge and Tokelau Seamounts are the only seamount trails in the Pacific Ocean with a sharp 60 degrees bend, similar to the Hawaii-Emperor bend (HEB). These two bends should be coeval with the 47-million-year-old HEB if they were formed by stationary hot spots, and assuming Pacific plate motion only. New 40Ar/39Ar ages indicate that the bends in the Gilbert Ridge and Tokelau seamount trail were formed much earlier than the HEB at 67 and 57 million years ago, respectively. Such asynchronous bends cannot be reconciled with the stationary hot spot paradigm, possibly suggesting hot spot motion or magmatism caused by short-term local lithospheric extension. 相似文献
107.
Harris AC Kamenetsky VS White NC van Achterbergh E Ryan CG 《Science (New York, N.Y.)》2003,302(5653):2109-2111
At a porphyry copper-gold deposit in Bajo de la Alumbrera, Argentina, silicate-melt inclusions coexist with hypersaline liquid- and vapor-rich inclusions in the earliest magmatic-hydrothermal quartz veins. Copper concentrations of the hypersaline liquid and vapor inclusions reached maxima of 10.0 weight % (wt %) and 4.5 wt %, respectively. These unusually copper-rich inclusions are considered to be the most primitive ore fluid found thus far. Their preservation with coexisting melt allows for the direct quantification of important oreforming processes, including determination of bulk partition coefficients of metals from magma into ore-forming magmatic volatile phases. 相似文献
108.
109.
Bird J 《Science (New York, N.Y.)》1991,253(5022):848-849
110.