全文获取类型
收费全文 | 2879篇 |
免费 | 152篇 |
国内免费 | 221篇 |
专业分类
林业 | 107篇 |
农学 | 137篇 |
基础科学 | 314篇 |
247篇 | |
综合类 | 883篇 |
农作物 | 61篇 |
水产渔业 | 101篇 |
畜牧兽医 | 1249篇 |
园艺 | 29篇 |
植物保护 | 124篇 |
出版年
2024年 | 15篇 |
2023年 | 58篇 |
2022年 | 62篇 |
2021年 | 114篇 |
2020年 | 77篇 |
2019年 | 127篇 |
2018年 | 57篇 |
2017年 | 83篇 |
2016年 | 122篇 |
2015年 | 95篇 |
2014年 | 114篇 |
2013年 | 148篇 |
2012年 | 244篇 |
2011年 | 197篇 |
2010年 | 152篇 |
2009年 | 188篇 |
2008年 | 161篇 |
2007年 | 162篇 |
2006年 | 145篇 |
2005年 | 123篇 |
2004年 | 114篇 |
2003年 | 97篇 |
2002年 | 94篇 |
2001年 | 78篇 |
2000年 | 59篇 |
1999年 | 45篇 |
1998年 | 44篇 |
1997年 | 39篇 |
1996年 | 35篇 |
1995年 | 42篇 |
1994年 | 29篇 |
1993年 | 15篇 |
1992年 | 24篇 |
1991年 | 12篇 |
1990年 | 20篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1956年 | 3篇 |
排序方式: 共有3252条查询结果,搜索用时 0 毫秒
81.
水貂阿留申病是水貂养殖业的重要疫病,目前无疫苗预防,主要通过发展诊断技术,淘汰感染貂防控该病。论文总结了在貂场应用的基因与抗体检测技术,基因检测具有高灵敏度和特异性,能够检测到动物带毒感染,不同类型的基因检测技术对变异性强的阿留申病毒检测各有所长;抗体检测是水貂阿留申病的主要检测方式,研究者不断创新和改进原有技术,趋向对阿留申病的规模化精准检测,但单一的抗体检测方法淘汰感染貂具有局限性。论文通过对两类检测技术分析,建议采用基因与抗体的联合检测方法,从感染貂群中区分耐受貂或抗性貂,期望为国内高感染率貂场的检测和选种提供参考。 相似文献
82.
83.
Kagawa S Klein F Corboz L Moore JE Murayama O Matsuda M 《Veterinary research communications》2001,25(7):565-575
Forty-six isolates of Taylorella equigenitalis were analysed by pulsed-field gel electrophoresis (PFGE) after separate digestion of the genomic DNA with ApaI and with NotI. The isolates had been obtained from horses in six European countries and were classified into 18 genotypes. In Belgium, 2 genotypes were detected in 2 isolates, in England 9 among 15, in Finland 2 in 2, in France 2 among 10, in Sweden 3 among 5, and in Switzerland 3 among 12. Two English isolates and 4 French isolates gave identical PFGE profiles to those of Kentucky 188 from the United States. A common genotype was found in 5 isolates from Belgium and England and also in 10 isolates from France and Switzerland. The analysis of genomic DNA from 12 isolates of T. equigenitalis obtained from male horses in France, Sweden and Switzerland gave no evidence of a sex-related difference in the genomic DNA. Genomic DNA from 11 streptomycin (STM)-susceptible isolates obtained in Sweden and Switzerland were classified into four genotypes by PFGE. Each of the six genotypes determined among the 17 isolates from these two countries had single phenotypes for resistance or susceptibility to STM. 相似文献
84.
Van den Bossche P Shumba W Njagu C Shereni W 《Tropical animal health and production》2001,33(5):391-405
Tsetse have been cleared from large areas of Zimbabwe during the past 65 years. In most areas, they are prevented from re-invading cleared areas by barriers of odour-baited, insecticide-treated targets. A trypanosomosis survey was conducted to determine the effectiveness of such barriers against re-invasion and to confirm the absence of tsetse in areas where they had previously been eradicated. Parasitological diagnostic methods and an anti-trypanosomal antibody detection enzyme-linked immunosorbent assay (antibody ELISA) were used. The prevalence of trypanosomal infections in the tsetse-cleared areas was generally low. However, the prevalence of anti-trypanosomal antibodies was unexpectedly high in some areas. This high proportion of cattle with antibodies could, in most cases, be explained by recent or historic information on the distribution and density of tsetse. The results from the survey demonstrated the value of anti-trypanosomal antibody detection as an additional sensitive tool for monitoring the effectiveness of tsetse control operations. 相似文献
85.
Leukocyte counts in bronchoalveolar lavage fluid obtained from normal and Maedi–Visna‐infected sheep
Panagiotis D. Katsoulos Georgios Christodoulopoulos Georgios Kontopidis Anastasios Minas Athanasia Tzivara Spyridon K. Kritas 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2009,38(3):397-402
Background: Bronchoalveolar lavage has proven helpful for the diagnosis of certain ovine diseases of the lungs. There is insufficient data concerning the leukocyte profile of bronchoalveolar lavage fluid (BALF) from MaediVisna infected sheep. Objective: The objective of this study was to assess the differential leukocyte profile of BALF associated with Maedi virus infection in sheep and to determine whether cytologic examination of BALF is an effective way to diagnose Maedi or determine the severity of lung lesions. Methods: BALF and serum samples were analyzed from 400 sheep. Sediment smears of bronchoalveolar lavage were stained with Diff‐Quik and examined microscopically to obtain a 200‐cell differential cell count. Serum was tested using a commercial kit for Maedi–Visna virus antibodies. Lung samples obtained at the time of slaughter were weighed and examined histologically. Results: Maedi‐infected sheep (n=267; seropositive with lung lesions) had a significantly higher percentage of lymphocytes and lower percentage of macrophages in BALF than normal sheep (n=133; seronegative and no lung lesions). These differences were significantly more severe in animals with advanced vs moderate lung lesions. Using classification trees, a cut‐off of 13.5% lymphocytes was predictive of Maedi infection and a cut‐off of 24.5% lymphocytes was predictive of advanced lung lesions. Conclusions: Cytologic examination of BALF is useful for the clinical diagnosis of Maedi in sheep and provides important information about the severity of the lung lesions. 相似文献
86.
87.
本研究以纯化的原核表达的猪轮状病毒VP7抗原表位区域为抗原,建立了检测猪轮状病毒抗体的间接ELISA诊断方法。特异性试验表明,该抗原与其他7种常见猪病病毒(TGEV、PEDV、CSFV、PCV2、PRRSV、PPV、PrV)的阳性血清不发生交叉反应,批内和批间重复性试验的变异系数均小于10%;对来自不同猪场的血清的检测结果表明,该ELISA方法与中和试验检测结果符合率达94.8%。本试验建立的ELISA诊断方法具有良好的重复性、敏感性和特异性,为PRV的快速诊断、免疫猪群抗体监测和轮状病毒流行病学调查提供了一种快速、简便的血清学诊断方法。 相似文献
88.
89.
90.