全文获取类型
收费全文 | 3460篇 |
免费 | 184篇 |
国内免费 | 1篇 |
专业分类
林业 | 126篇 |
农学 | 129篇 |
基础科学 | 8篇 |
581篇 | |
综合类 | 370篇 |
农作物 | 480篇 |
水产渔业 | 248篇 |
畜牧兽医 | 1502篇 |
园艺 | 40篇 |
植物保护 | 161篇 |
出版年
2022年 | 56篇 |
2021年 | 88篇 |
2020年 | 50篇 |
2019年 | 56篇 |
2018年 | 90篇 |
2017年 | 86篇 |
2016年 | 90篇 |
2015年 | 95篇 |
2014年 | 131篇 |
2013年 | 184篇 |
2012年 | 199篇 |
2011年 | 245篇 |
2010年 | 131篇 |
2009年 | 116篇 |
2008年 | 207篇 |
2007年 | 208篇 |
2006年 | 141篇 |
2005年 | 151篇 |
2004年 | 149篇 |
2003年 | 133篇 |
2002年 | 114篇 |
2001年 | 77篇 |
2000年 | 69篇 |
1999年 | 48篇 |
1998年 | 17篇 |
1997年 | 26篇 |
1996年 | 18篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 37篇 |
1991年 | 40篇 |
1990年 | 37篇 |
1989年 | 31篇 |
1988年 | 22篇 |
1987年 | 34篇 |
1986年 | 30篇 |
1985年 | 35篇 |
1984年 | 30篇 |
1983年 | 21篇 |
1979年 | 20篇 |
1978年 | 12篇 |
1977年 | 21篇 |
1976年 | 12篇 |
1974年 | 17篇 |
1973年 | 23篇 |
1972年 | 18篇 |
1971年 | 14篇 |
1970年 | 18篇 |
1969年 | 20篇 |
1968年 | 13篇 |
排序方式: 共有3645条查询结果,搜索用时 218 毫秒
941.
First report of Exobasidium gracile causing hypertrophied leaves of Camellia sasanqua in South Korea
下载免费PDF全文
![点击此处可从《Forest Pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This study presents the first report of Exobasidium gracile in South Korea. In 2012, a Camellia sasanqua tree with typical Exobasidium disease symptoms was observed for the first time in South Korea. The causal fungus was determined as E. gracile. The identification was based on host range, symptomatology, morphology and two‐gene sequence analyses. 相似文献
942.
K Auty M Auty T Faragher M Harrison D Paxton P Young J Whittem 《Australian veterinary journal》2014,92(8):291-291
943.
A. E. Mouradian‐Darby B. D. Young J. F. Griffin IV J. Mansell J. M. Levine 《The Journal of small animal practice》2014,55(9):471-474
This study presents a case of lymphocytic ganglioneuritis in a dog secondary to intervertebral disc extrusion that mimicked a peripheral nerve sheath tumour on magnetic resonance imaging. A four‐year‐old spayed female dachshund with lumbar pain was imaged via magnetic resonance. A tubular, space‐occupying, contrast‐enhancing lesion was noted in the right intervertebral foramen at L6 to L7. This was presumed to represent focal enlargement of the right sixth lumbar spinal nerve. A right‐sided haemilaminectomy was performed at L6 to L7 and material that grossly resembled extruded nucleus pulposus was removed. The right L6 dorsal root ganglion, dorsal nerve root and proximal spinal nerve were severely enlarged and a partial thickness biopsy was collected from the dorsal root ganglion. Results of histopathological examination of the submitted tissue samples were consistent with extruded disc material and lymphocytic ganglioneuritis. To the author's knowledge, this is the first published report of lymphocytic ganglioneuritis secondary to intervertebral disc disease in a dog. 相似文献
944.
The present study was undertaken to compare the effect of salinomycin and Bacillus subtilis on growth performance, serum antibody levels against Clostridium spp. and Eimeria spp., and cytokine mRNA expression levels in broiler chickens raised in the used litter. Broiler chickens fed a diet containing salinomycin showed lower (P < 0.05) body weights compared with the control diet-fed counterparts. Serum nitric oxide levels were significantly (P < 0.05) elevated in chickens fed the B. subtilis-enriched diet compared with those on either the salinomycin-fed or control diet-fed chickens. None of the dietary treatments affected (P > 0.05) serum antibody levels against Clostridium perfringens toxins. Both salinomycin and B. subtilis significantly lowered (P < 0.05) the serum levels of Eimeria-specific antibodies compared with the control group. Salinomycin, but not B. subtilis, significantly modulated (P < 0.05) the expression of cytokines encoding interferon-γ (IFN-γ), interleukin10 (IL-10) and tumor necrosis factor superfamily 15 (TNFSF15) compared with the control group. In conclusion, dietary salinomycin and B. subtilis affected serum anticoccidial antibody and intestinal cytokine expression, but failed to improve growth performance in broiler chickens. Further study is warranted to investigate the mode of action of salinomycin on host immune response and growth performance in broiler chickens. 相似文献
945.
946.
Ian Young Lisa Waddell Javier Sanchez Barbara Wilhelm Scott A. McEwen Andrijana Rajić 《Preventive veterinary medicine》2014
Knowledge synthesis refers to the integration of findings from individual research studies on a given topic or question into the global knowledge base. The application of knowledge synthesis methods, particularly systematic reviews and meta-analysis, has increased considerably in the agri-food public health sector over the past decade and this trend is expected to continue. The objectives of our review were: (1) to describe the most promising knowledge synthesis methods and their applicability in agri-food public health, and (2) to summarize the recent advancements, challenges, and opportunities in the use of systematic review and meta-analysis methods in this sector. We performed a structured review of knowledge synthesis literature from various disciplines to address the first objective, and used comprehensive insights and experiences in applying these methods in the agri-food public health sector to inform the second objective. We describe five knowledge synthesis methods that can be used to address various agri-food public health questions or topics under different conditions and contexts. Scoping reviews describe the main characteristics and knowledge gaps in a broad research field and can be used to evaluate opportunities for prioritizing focused questions for related systematic reviews. Structured rapid reviews are streamlined systematic reviews conducted within a short timeframe to inform urgent decision-making. Mixed-method and qualitative reviews synthesize diverse sources of contextual knowledge (e.g. socio-cognitive, economic, and feasibility considerations). Systematic reviews are a structured and transparent method used to summarize and synthesize literature on a clearly-defined question, and meta-analysis is the statistical combination of data from multiple individual studies. We briefly describe and discuss key advancements in the use of systematic reviews and meta-analysis, including: risk-of-bias assessments; an overall quality-of-evidence approach; engagement of stakeholders; Bayesian, multivariate, and network meta-analysis; and synthesis of diagnostic test accuracy studies. We also highlight several challenges and opportunities in the conduct of systematic reviews (e.g. inclusion of grey literature, minimizing language bias, and optimizing search strategies) and meta-analysis (e.g. inclusion of observational studies and approaches to address the insufficient reporting of data and significant heterogeneity). Many of these developments have yet to be comprehensively applied and evaluated in an agri-food public health context, and more research is needed in this area. There is a need to strengthen knowledge synthesis capacity and infrastructure at the regional, national, and international levels in this sector to ensure that the best available knowledge is used to inform future decision-making about agri-food public health issues. 相似文献
947.
948.
949.
950.
Z. Edea H. Dadi S.‐W. Kim J.‐H. Park G.‐H. Shin T. Dessie K.‐S. Kim 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2014,131(5):358-366
Despite the wide range of observed phenotypic diversities and adaptation to different ecological conditions, little has been studied regarding the genetics of adaptation in the genome of indigenous cattle breeds of developing countries. Here, we investigated the linkage disequilibrium (LD) and identified the subset of outlier loci that are highly differentiated among cattle populations adapted to different ecological conditions in Ethiopia. Specifically, we genotyped 47 unrelated animals sampled from high‐ versus low‐altitude environments using a Bovine 50K SNP BeadChip. Linkage disequilibrium was assessed using both D′ and r2 between adjacent SNPs. We calculated FST and heterozygosity at different significance levels as measures of genetic differentiation for each locus between high‐ and low‐altitude populations following the hierarchical island model approach. We identified 816 loci (p < 0.01) showing selection signals and are associated with genes that might have roles in local adaptation. Some of them are associated with candidate genes that are involved in metabolism (ATP2A3, CA2, MYO18B, SIK3, INPP4A, and IREB2), hypoxia response (BDNF, TFRC, and PML) and heat stress (PRKDC, CDK1, and TFDC). Average r2 and D′ values were 0.14 ± 0.21 and 0.57 ± 0.34, respectively, for a minor allele frequency (MAF) ≥ 0.05 and were found to increase with increasing MAF value. The outlier loci identified in the studied Ethiopian cattle populations indicate the presence of genetic variation produced/shaped by adaptation to different environmental conditions and provide a basis for further validation and functional analysis using a reasonable sample size and high‐density markers. 相似文献