全文获取类型
收费全文 | 4767篇 |
免费 | 242篇 |
国内免费 | 333篇 |
专业分类
林业 | 215篇 |
农学 | 321篇 |
基础科学 | 34篇 |
391篇 | |
综合类 | 1464篇 |
农作物 | 404篇 |
水产渔业 | 204篇 |
畜牧兽医 | 833篇 |
园艺 | 1159篇 |
植物保护 | 317篇 |
出版年
2024年 | 14篇 |
2023年 | 70篇 |
2022年 | 102篇 |
2021年 | 122篇 |
2020年 | 193篇 |
2019年 | 242篇 |
2018年 | 175篇 |
2017年 | 181篇 |
2016年 | 246篇 |
2015年 | 234篇 |
2014年 | 247篇 |
2013年 | 265篇 |
2012年 | 333篇 |
2011年 | 381篇 |
2010年 | 262篇 |
2009年 | 284篇 |
2008年 | 281篇 |
2007年 | 335篇 |
2006年 | 233篇 |
2005年 | 149篇 |
2004年 | 187篇 |
2003年 | 148篇 |
2002年 | 127篇 |
2001年 | 82篇 |
2000年 | 77篇 |
1999年 | 56篇 |
1998年 | 47篇 |
1997年 | 34篇 |
1996年 | 38篇 |
1995年 | 30篇 |
1994年 | 23篇 |
1993年 | 21篇 |
1992年 | 24篇 |
1991年 | 14篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 6篇 |
1986年 | 9篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1962年 | 3篇 |
1956年 | 1篇 |
排序方式: 共有5342条查询结果,搜索用时 512 毫秒
1.
Single nucleotide polymorphisms (SNPs) of cytokine genes have been found to be involved in the clinical outcome of Tuberculosis. The present study was aimed to identify the high risk genotypes in Tuberculosis patients and their household contacts. A total of 490 subjects were studied which includes 150 active pulmonary tuberculosis patients (APTB), 190 household contacts (HHC) and 150 healthy controls (HC). The SNPs of TNF-α (-308A/G), IL-10(-1082G/A) and IL-6(-174G/C) were performed by ARMs PCR. The IL-10 GA genotype showed significant association in APTB and HHC and was 2.3 times higher risk in APTB and 3.7 times in HHC compared to HCs. The A allele was found to be significantly associated with the risk of disease. The CC genotype of IL-6 was found to be significantly associated in APTB and an insignificant positive association in HHCs. The multifactor dimensionality reduction (MDR) analysis indicated that the genotypes of IL-6 were showing high risk with GA genotype of IL-10. In conclusion the gene interaction may be useful for identification of genotypes as biomarkers to distinguish high risk individuals. 相似文献
2.
豫谷6号是应用有性杂交技术,经连续南繁、温室加代选择育成的夏谷新品种。具有高产稳产、高抗倒伏、高度抗旱、综合抗病力强等优良特性,适宜中等以上肥力水、旱地种植。 相似文献
3.
赤霉素及机械处理的相互作用对破除Sandersonia aurantiaca种子休眠的研究 总被引:11,自引:4,他引:7
在预备试验的基础上,选用了21种促进种子发芽的方法,结果显示,完整的s.aurantiaca种子对任何处理都无响应,砂纸磨擦 近胚根处切除小部分可使种子发芽率提高至11%。以上处理结合300mg/L GA3溶液的使用可破除种子休眠,使种子发芽率提高到69%以上。结果还表明,S.aurantiaca种子发芽的适宜温度为20℃;25℃ 16h/d光照及30℃的条件可降低种子的发芽率。研究还对S.aurantiaca种子的吸胀能力以及所含抑制物对生菜种子发芽的影响进行了比较。初步得出,S.aurantiaca种子具有种皮限制和种胚休眠的双重休眠机制,GA3和机械处理的相互作用可破除种子休眠。 相似文献
4.
Growth of triploid oyster, Crassostrea madrasensis (Preston) 总被引:1,自引:0,他引:1
The performance of I and II meiotic triploids and control oysters (Crassostrea madrasensis) reared at Tuticorin Bay was compared to determine if the improvements in the growth of edible oysters were additive to faster growth in triploids. After a grow‐out period of 12 months, both mean whole weights and shell heights were in order I meiotic triploid>II meiotic triploid>control. Mean whole weights and shell height of different oyster lines were all significantly different (P<0.05). On an average, larger morphological traits indicated that growth improvements from triploids were additive, and throughout the study triploid oysters maintained faster growth rate than their diploid siblings. Condition index and adductor muscle diameter of both triploids were higher than those of control. 相似文献
5.
6.
7.
8.
9.
10.
Although the molluscicide Frescon is a strong neurotoxin to the Lymnaea stagnalis central nervous system in vitro, it is probable that the exposure of the whole animal to this molluscicide fails to result in central nervous system abnormalities: Frescon does not appear to reach the brain in sufficient quantity to disrupt its normal activity. However, only those Frescon analogs found to be neurotoxic were molluscicidal, suggesting some related mode, if not site, of action. Frescon and its analogs may act by affecting excitable tissues other than the nervous system (e.g., the snail musculature) by altering certain functional and/or structural membrane properties. 相似文献