全文获取类型
收费全文 | 23582篇 |
免费 | 260篇 |
国内免费 | 834篇 |
专业分类
林业 | 233篇 |
农学 | 570篇 |
基础科学 | 123篇 |
244篇 | |
综合类 | 5077篇 |
农作物 | 196篇 |
水产渔业 | 1043篇 |
畜牧兽医 | 16324篇 |
园艺 | 344篇 |
植物保护 | 522篇 |
出版年
2024年 | 81篇 |
2023年 | 242篇 |
2022年 | 288篇 |
2021年 | 304篇 |
2020年 | 307篇 |
2019年 | 469篇 |
2018年 | 133篇 |
2017年 | 302篇 |
2016年 | 437篇 |
2015年 | 540篇 |
2014年 | 1226篇 |
2013年 | 1141篇 |
2012年 | 1704篇 |
2011年 | 1820篇 |
2010年 | 1381篇 |
2009年 | 1590篇 |
2008年 | 1629篇 |
2007年 | 1532篇 |
2006年 | 1381篇 |
2005年 | 1306篇 |
2004年 | 1004篇 |
2003年 | 957篇 |
2002年 | 669篇 |
2001年 | 611篇 |
2000年 | 486篇 |
1999年 | 321篇 |
1998年 | 354篇 |
1997年 | 388篇 |
1996年 | 341篇 |
1995年 | 333篇 |
1994年 | 267篇 |
1993年 | 242篇 |
1992年 | 249篇 |
1991年 | 201篇 |
1990年 | 175篇 |
1989年 | 185篇 |
1988年 | 20篇 |
1987年 | 11篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1977年 | 2篇 |
1965年 | 3篇 |
1958年 | 3篇 |
1957年 | 5篇 |
1956年 | 4篇 |
1953年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
以猪瘟弱毒疫苗免疫空怀母猪,待母猪分娩后,分别收集10d内的乳汁,以建立的间接ELISA法检测猪瘟IgA、IgG、IgM水平,并观察各种抗体动态变化规律。试验结果表明,猪初乳中的IgA、IgG、IgM抗体效价均在分娩当天达到最高值,随后迅速下降,7d后抗体水平与常乳基本一致(>0.05)。对照组母猪仅在分娩当天检测到较低的抗体水平。 相似文献
995.
鱼用基因疫苗的研究进展 总被引:2,自引:0,他引:2
DNA疫苗是一种新型疫苗。本文主要对鱼用DNA疫苗的构建、作用机制、使用方法、使用效果及安全问题等方面研究近况作一综述,以促进我国对鱼用DNA疫苗进一步的研究和应用,为深入研究和掌握鱼类的免疫防御机制提供一些理论依据。 相似文献
996.
997.
MO Jiayuan GAO Jiuyu FENG Lingli LI Yueyue TIAN Weilong LIU Xiaoxiao CHENG Feng LIANG Liang LEI Shuqiao WEN Wei LIANG Jing LAN Ganqiu 《中国畜牧兽医》2007,47(12):3965-3975
In order to identify the molecular markers related to alive litter size of Bama Xiang pigs,the genome-wide association study (GWAS) was used to map and screen the candidate genes affecting the alive litter size trait.Ear tissue samples of 297 Bama Xiang pigs with multiple parity records were collected,and DNA was extracted and genotyped by porcine 50K SNP beadchip.After quality control and genotype imputation,the alive litter size of Bama Xiang pigs were GWAS by Tassel.The results showed that the average number born alive per litter of Bama Xiang pigs increased gradually with the increasing of parity in the range of 1-9 parities.A total of 32 816 SNPs were obtained after quality control and filtration.8 SNPs related to alive litter size of Bama Xiang pigs were screened by genome-wide association analysis,which were significant at genome or chromosome level.Based on the enrichment analysis of the coding genes in the region between 500 kb upstream and downstream of the associated significant SNP loci,and the QTL regions and gene functions related to porcine reproductive traits,4 genes (CAPZB,MSH3,CITED2 and HSD17B7) were finally identified to be candidate genes related to alive litter size of Bama Xiang pigs. 相似文献
998.
XIONG Xiaoyan QIN Zhenbin MO Hongfang HE Dongxian YU Lintian XU Jiarong 《中国畜牧兽医》2007,47(12):4032-4040
This study was designed to evaluate the synergistic effect of VA5 immunopotentiator on pigeon ND4416 inactivated vaccine.160 healthy pigeons were randomly divided into four groups,including ND4416 strain inactivated vaccine group (NDV group),ND4416 strain inactivated vaccine and immunopotentiator (VA5) mixed group (NDV+VA5 group),La Sota inactivated vaccine group (La Sota group) and normal saline as the control group (C group),to assess their vaccine efficacy against virulent pigeon NDV by serological analysis and animal testing.Pigeons sera were collected at different time points after immunization and measured the HI antibody titer of each group.The results showed that VA5 immunopotentiator significantly improved the serum antibody level of pigeons immunized with pigeon Newcastle disease inactivated vaccine (P<0.05).In addition,comparative test of spleen lymphocyte transformation was conducted at various time points after immunization.The results indicated that VA5 effectively stimulated the lymphocyte transformation of immune pigeon.Pigeons in each groups were challenged with ND4416 strain at the 30th,90th and 180th d after immunization.The results presented that the NDV+VA5 group had 100% protection rate and higher than La Sota group.The duration of immunization test showed that the antibody titer of NDV+VA5 group reached peak 11.20log2 at the 21st d,remained 7.50log2 at 180th d,and the protection rate remained 100% at 180th d.It indicated that VA5 immunopotentiator sustained the immune duration of pigeon NDV vaccine up to 180 d.Moreover,the in vitro detoxification test results suggested that VA5 immunopotentiator reduced the in vitro detoxification cycle of pigeons after challenge.Overall,this study suggested VA5 immunopotentiator could significantly improve the immune efficacy of pigeon Newcastle disease inactivated vaccine,which provided a basis for further enhancing the efficacy of Newcastle disease vaccine,as well increased experimental data for the application of immunopotentiators. 相似文献
999.