全文获取类型
收费全文 | 8996篇 |
免费 | 117篇 |
国内免费 | 16篇 |
专业分类
林业 | 862篇 |
农学 | 295篇 |
基础科学 | 55篇 |
1187篇 | |
综合类 | 404篇 |
农作物 | 563篇 |
水产渔业 | 683篇 |
畜牧兽医 | 4262篇 |
园艺 | 224篇 |
植物保护 | 594篇 |
出版年
2021年 | 46篇 |
2020年 | 26篇 |
2019年 | 30篇 |
2018年 | 154篇 |
2017年 | 221篇 |
2016年 | 213篇 |
2015年 | 304篇 |
2014年 | 277篇 |
2013年 | 298篇 |
2012年 | 556篇 |
2011年 | 434篇 |
2010年 | 148篇 |
2009年 | 145篇 |
2008年 | 173篇 |
2007年 | 138篇 |
2006年 | 141篇 |
2005年 | 858篇 |
2004年 | 737篇 |
2003年 | 524篇 |
2002年 | 165篇 |
2001年 | 172篇 |
2000年 | 55篇 |
1999年 | 161篇 |
1992年 | 120篇 |
1991年 | 147篇 |
1990年 | 170篇 |
1989年 | 148篇 |
1988年 | 173篇 |
1987年 | 115篇 |
1986年 | 148篇 |
1985年 | 122篇 |
1984年 | 94篇 |
1983年 | 81篇 |
1982年 | 35篇 |
1980年 | 25篇 |
1979年 | 134篇 |
1978年 | 99篇 |
1977年 | 94篇 |
1976年 | 77篇 |
1975年 | 137篇 |
1974年 | 131篇 |
1973年 | 117篇 |
1972年 | 139篇 |
1971年 | 120篇 |
1970年 | 88篇 |
1969年 | 102篇 |
1968年 | 114篇 |
1967年 | 126篇 |
1966年 | 103篇 |
1965年 | 70篇 |
排序方式: 共有9129条查询结果,搜索用时 15 毫秒
1.
大豆抗菌核病的全基因组关联研究 总被引:2,自引:0,他引:2
找到大豆与抗菌核病强关联的候选位点或候选基因,为抗病基因克隆和抗病分子标记开发提供借鉴,服务大豆抗菌核病育种。对126个加拿大大豆品种的基因组DNA用ApekⅠ酶消化后Illumina Hiseq2000平台测序进行基因分型,供试的126个材料用棉垫接种核盘菌菌丝体进行表型鉴定。采用Structure 2.3.4、SPSS 20.0、TASSEL 5.0和PLINKv 1.07软件分别模拟群体遗传结构、二元主成分分析、邻接法聚类,进行SNP-phenotype和Haplotype-phenotype的关联分析(只考虑加性效应)。最小等位基因频率0.01过滤,得到30 125个SNPs。主成分及群体结构聚类结果中度一致,将126个供试材料划分为2个组群,Kappa聚类一致度检验K=0.44。邻接法(The neighbor-joining algorithm,NJ)聚为3个组群。α≤0.05时,在单个SNP-phenotype的关联研究中,最强关联在3号染色体物理位置34387780、34387823和34387841处(P值都为8.669E-7),可分别解释表型变异的17.80%,其次在20,1,4,17号染色体上。Haplotype-phenotype的关联分析中,最强关联在17号染色体物理位置5575883/5647814/5648648/5734897处(P值为1.038E-6),可解释表型变异的17.56%。200 kb范围内,3号染色体上的候选基因有Glma.03g129100、Glma.03g129200、Glma.03g129300、Glma.03g129500、Glma.03g129800、Glma.03g129900。17号染色体上为Glma.17g071300、Glma.17g072200、Glma.17g073300。 相似文献
2.
3.
高产优质杂交稻新品种钱优3301系福建省农业科学院生物技术研究所与浙江省农业科学院作物与核技术利用研究所用钱江1A/闽恢3301联合培育的,2014年通过福建省农作物品种审定。2016年引入闽清县种植,平均产量达9 127.9 kg/hm~2,具有株型适中、群体整齐、综合性状好、稻米品质优等特点。总结了钱优3301在闽清县种植表现及高产栽培技术。 相似文献
4.
5.
6.
水稻机械化插秧能够大幅度提高劳动生产率,减轻劳动强度,降低生产成本,达到增产增收的效果。试验结果表明:水稻机插栽培有效穗数多,有利于形成较为合理的群体结构,从而穗粒数较多,结实率提高,产量高,增产效果明显。 相似文献
7.
Saddleback-like syndrome is one of the most frequently observed malformations in hatchery-reared red spotted grouper Epinephelus akaara. Saddleback-like syndrome is characterized by a V-shaped dorsal-profile depression behind the head region accompanied by deformities or misalignments of the first to fourth neural spines on the vertebral column and the first to fourth pterygiophores of the dorsal fin. Abnormal swim bladder inflation in several finfish species leads to malformations, particularly of the vertebral column. The present study examined the influence of swim bladder inflation on saddleback-like syndrome in hatchery-reared red spotted grouper. The incidence of saddleback-like syndrome increased as swim bladder inflation rate increased. Additionally, the incidence of saddleback-like syndrome among juveniles with inflated swim bladders was significantly higher than that among juveniles with uninflated swim bladders. The larval swim bladder is located just below the first to fifth vertebrae and the first to fifth dorsal spines, where saddleback-like syndrome occurs. Our results suggest that an inflated swim bladder increases the risk of saddleback-like syndrome in hatchery-reared red spotted grouper. 相似文献
8.
Recreational angling is a popular leisure activity globally and can be a threat or useful conservation tool depending on the management strategy. Miyabe charr Salvelinus malma miyabei is an endemic fish that inhabits Lake Shikaribetsu, and a management program was established to harmonise recreational fishery and conservation. To examine the suitability of this program, population assessment was conducted with the cooperation of anglers. The population size in 2014 as assessed by tag-and-release angling was estimated to be 105,300 [95% confidence interval (CI) 37,300–178,600], much higher than the reported estimate in 1995. Further, angling mortality was estimated to be quite low. Moreover, no decreasing population trend was detected on analysing 8 years of anglers’ catch data. Consequently, angling has facilitated stock assessments of Miyabe charr under the current program. This case is a good example of recreational angling acting as a conservation tool under appropriate management. 相似文献
9.
Fumitaka Kondo Takashi Ohta Toshiharu Iwai Atsushi Ido Chiemi Miura Takeshi Miura 《Fish physiology and biochemistry》2017,43(6):1543-1555
The improvement in feed efficiency is one of the most important subjects in fish culture. The development of feed, in terms of good intake, high growth performance, and high feed efficiency is needed. Squid viscera are one of the candidates for alternative material in improving feed efficiency in fish culture. In the present study, we described the dietary effect of the squid viscera hydrolysate (SVH) on the growth performance of the red sea bream. The addition of SVH to feed caused significant increases in feed intake, fork length, and body weight and produced a marked improvement in feed conversion after 4 weeks of feeding. Furthermore, the results of this feeding revealed that low dietary levels of SVH promote growth performance in the red sea bream. We physiologically analyzed digestion and appetite in fish fed diet containing SVH. SVH promoted the activity of hepatic trypsin and lipase, gene expression of stomach pepsin, hepatic lipase, and pyloric caeca trypsin, thereby improving the nutrient availability in red sea bream. Moreover, the mRNA expression of appetite regulating factor, such as brain NPY and stomach ghrelin was significantly improved by dietary SVH. Our current results indicate that dietary SVH as alternative material produced excellent effects on growth performance, which is dependent on the promoting effect on digestion and appetite in red sea bream. 相似文献
10.