全文获取类型
收费全文 | 5124篇 |
免费 | 117篇 |
国内免费 | 349篇 |
专业分类
林业 | 210篇 |
农学 | 442篇 |
基础科学 | 276篇 |
173篇 | |
综合类 | 2640篇 |
农作物 | 471篇 |
水产渔业 | 95篇 |
畜牧兽医 | 745篇 |
园艺 | 455篇 |
植物保护 | 83篇 |
出版年
2024年 | 34篇 |
2023年 | 143篇 |
2022年 | 176篇 |
2021年 | 180篇 |
2020年 | 157篇 |
2019年 | 195篇 |
2018年 | 101篇 |
2017年 | 137篇 |
2016年 | 196篇 |
2015年 | 188篇 |
2014年 | 188篇 |
2013年 | 243篇 |
2012年 | 270篇 |
2011年 | 317篇 |
2010年 | 295篇 |
2009年 | 326篇 |
2008年 | 329篇 |
2007年 | 275篇 |
2006年 | 227篇 |
2005年 | 255篇 |
2004年 | 245篇 |
2003年 | 201篇 |
2002年 | 196篇 |
2001年 | 153篇 |
2000年 | 96篇 |
1999年 | 90篇 |
1998年 | 64篇 |
1997年 | 40篇 |
1996年 | 59篇 |
1995年 | 42篇 |
1994年 | 41篇 |
1993年 | 19篇 |
1992年 | 29篇 |
1991年 | 18篇 |
1990年 | 32篇 |
1989年 | 18篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有5590条查询结果,搜索用时 15 毫秒
131.
采用PCR-SSCP技术,对五指山猪、海南地方猪2个品系(临高猪、屯昌猪)等猪种的IGFBP6基因的多态性进行研究。结果表明,引物P1和P2的PCR片断SSCP分析表现有多态性,且出现3种基因型。随后的测序结果表明,它们都在相应的区域存在着变异;引物P1在海南地方猪种大多表现BB基因型和以B等位基因为主,引物P2大多表现CC基因型和以C等位基因为主。SPSS软件分析五指山猪IGFBP6基因多态性与其3个生长阶段的关联程度,结果发现,引物P1 AA基因型和引物P2 DD基因型的猪个体在2月龄、8月龄、12月龄的生长体重高于其它基因型,但个体差异均不显著(P0.05)。 相似文献
132.
LIU Yong-fa HUANG Yu-mei ZHANG Zong-yao WAN Hong WANG Mei LV Jia-min LUO Kai-jian 《中国畜牧兽医》2015,42(8):2176-2182
To investigate the pathogenicity of A/Hero/Guangdong/C1/2013(H5N6), an AIV strain isolated from Heron on ducks and mice, pathogenicity of this new virus strain and changing of histopathology as well as a preliminary study on its biological characteristics were studied by virus challenges test via intranasal and eye-drop and in chicken via jugular vein injection.Results showed that the EID50 of this strain of virus was 10-8.16/0.1 mL in embryonated chicken eggs and the intravenous inoculation of pathogenic index (IVPI) was 2.76.In ducks and mice, the 50% lethal doses (LD50) of it were determined to be 10-4.0/0.2 mL and 10-4.67/0.05 mL, respectively.Symptoms of infection included loss of appetite, depression, swollen head and tears after being infected with 106 EID50 per duck by intranasal and eye-drop administration.Most of ducks died 4 to 7 days post-infection, liver, lung and kidney still eliminated toxicants at day 7 post-infection.Anatomy showed symptoms of pericardial effusion, pulmonary congestion and kidney enlargement, while pathological section showed pathological change like karyopycnosis and inflammatory cell infiltration in heart, liver, kidney and spleen.Mice developed symptoms of infection like loss of appetite, depression, shaggy coat and ruffled coat after being infected with 5×105 EID50 per mouse by intranasal and eye-drop administration.Most of the infected mice died 5 to 7 days post-infection and only liver still eliminated toxicants at day 7 post-infection.Although organ anatomy showed no obvious pathological changes, pathological section showed pathological changes like karyopycnosis and inflammatory cell infiltration in heart, kidney and lung.Our research demonstrated that this H5N6 subtype AIV had a strong pathogenicity and could be defined as a highly pathogenic AIV strain as its IVPI was greater than 1.2.Our work laid a theory foundation for study, prevention and control of H5N6 subtype AIV. 相似文献
133.
134.
135.
KANG Jing-jing ZHAO De-ming TENG Ke-dao JIAO Xi-lan WANG Ping-li SUN Zhe NI Pei-pei WANG Zhi-feng ZHANG Rui YANG Yu-rong LIANG Hong-de 《农业科学学报》2014,13(4):858-869
Ulcerative colitis (UC) is a lifelong illness with profound emotional and social impacts, and could cause serious damage to large intestine, especially in colon. However, the pathogenesis of UC remained unclear. The present study attempts to find out the role of matrix metalloproteinases-7 (MMP-7) and lysozyme in the pathogenesis of UC through a mice model induced by dextran sulfate sodium (DSS). The UC model was evaluated both by disease activity index (DAI) and the intestinal histopathology. The results show that there is a high correlation between the DAI score and the pathological changes of colon. Interleukin-6 (IL-6) serum levels and large intestinal fluids levels in UC mice are always higher than that of the control groups, which might be associated with the degree of the inflammation damage in the colon. The change tendency of the MMP-7 mRNA and protein expressions are both up-regulated firstly and then down-regulated from 1 to 5 d in the colon, but only the MMP-7 protein is up-regulated at 7 d again. The up-regulated MMP-7 levels in the early stage of UC may play a protective role through the activated defensins, while the down-regulated levels in the mid-later stage of UC may be connected with the severe lesions in the colon. However, the up-regulated MMP-7 levels in the later stage of UC in the colon may also contribute to the tissue repair or be served as a marker to CRC (colorectal cancer). The distribution of lysozyme protein indicates that there may be Paneth-like cells in the colon. Both the changes of MMP-7 and lysozyme in the small intestine may play a protective role for the safe environment of the whole gut, especially to the colon of UC. 相似文献
136.
5个芒果品种在广西龙州的引种试验 总被引:2,自引:0,他引:2
2008年在广西龙州县引种栽培热农1号、热农2号、西贡芒、红芒6号、金煌芒共5个芒果品种。经过田间观察比较,热农2号抗逆性强,丰产性好,果实中等,肉质细腻,香甜多汁,纤维中等,品质优良;金煌芒抗逆性强,丰产性好,果实特大,外观好,晚熟,耐贮运,味甜多汁,纤维少,品质好,这2个品种可在龙州县推广种植。 相似文献
137.
138.
枯草芽孢杆菌PB6菌株是由建明工业(Kemin Industries)生产,在美国FDA注册的从健康鸡肠道中分离出来的益生菌。PB6活性菌株能通过分泌细菌素,直接杀灭魏氏梭菌(产气荚膜梭菌),并抑制大肠杆菌、沙门氏菌等需氧菌的生长,促进乳酸杆菌、双歧杆菌等有益厌氧菌的增殖,从而防止由梭菌引起的坏死性肠炎的爆发。同时,PB6活性菌株还能抵御高温的破坏,与生产应用上常用的酸、抗生素兼容。 相似文献
139.
140.
一书是《动物药剂科技精典》电子版全书,一网是"南宁兽药科技网"(南网),"1+6"就是畜禽渔"1+6工程药剂",以上简称"1书1网1+6"。这是广西大学"产学研"基地所属"广西北部湾(南宁)兽药科技网络中心"(南药中心)研发推广用于保障畜禽渔"养殖安全生产"的成套科技,使养殖获得满意效果的服务性举措。现代养殖与兽药科技的发展日新月异,养殖生产者要防治疫病侵、提高动物保健的能力,必须掌握现代养殖及兽药(含饲料药剂)应用的科学技术",1书1网1+6"能够全面提供这些方面的知识和有效药品(科技+药品),是目前能够给力予养殖业的有效配套工具,用以促进良好养殖愿望的实现。 相似文献