全文获取类型
收费全文 | 376篇 |
免费 | 19篇 |
国内免费 | 1篇 |
专业分类
林业 | 52篇 |
农学 | 9篇 |
基础科学 | 1篇 |
89篇 | |
综合类 | 34篇 |
农作物 | 22篇 |
水产渔业 | 16篇 |
畜牧兽医 | 123篇 |
园艺 | 17篇 |
植物保护 | 33篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 12篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 22篇 |
2013年 | 13篇 |
2012年 | 27篇 |
2011年 | 32篇 |
2010年 | 21篇 |
2009年 | 25篇 |
2008年 | 29篇 |
2007年 | 30篇 |
2006年 | 27篇 |
2005年 | 23篇 |
2004年 | 11篇 |
2003年 | 15篇 |
2002年 | 19篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有396条查询结果,搜索用时 547 毫秒
91.
Martina Mosing Dr med vet Diplomate ECVAA Jan M Kuemmerle† Dr med vet Agnes Dadak‡ PhD & Yves PS Moens Dr med vet PhD Diplomate ECVAA 《Veterinary anaesthesia and analgesia》2009,36(3):255-260
Observations A case of a pony with severe cyanide intoxication as a result of cherry ingestion is presented. General anaesthesia was performed for colic surgery. Severe metabolic lactate acidosis in combination with a high arterial oxygen partial pressure and clinically good peripheral perfusion parameters were the remarkable signs during anaesthesia. Severe hypothermia was obvious during recovery. Ten hours post-surgery the pony was euthanized as a result of neurological signs. The diagnosis of cyanide intoxication was made post-mortem.
Conclusion Cherry ingestion can lead to lethal cyanide intoxication in horses indicated by severe nonhypoxic lactic acidosis during anaesthesia. 相似文献
Conclusion Cherry ingestion can lead to lethal cyanide intoxication in horses indicated by severe nonhypoxic lactic acidosis during anaesthesia. 相似文献
92.
Zoulikha Krimi Aïda Raio Annik Petit Xavier Nesme Yves Dessaux 《European journal of plant pathology / European Foundation for Plant Pathology》2006,116(3):237-246
In the Sidi M’djahed nursery (Algeria), over 60,000 eucalyptus (Eucalyptus occidentalis) plantlets exhibited tumour-like growths localized at the crown of the plants that resembled crown galls caused by Agrobacterium tumefaciens. Bacteria colonizing the galls were isolated and purified. Most (22 out of 24) of the isolates had cultural and biochemical characteristics similar to those of strains of the biovar 1 of A. tumefaciens. Twenty out of 22 Agrobacterium isolates induced tumour formation on various test plants. In PCR experiments, DNA extracted from these virulent strains yielded an amplification signal corresponding to a 247-bp fragment located within the virulence region of nopaline type Ti plasmid. Consistent with this, the opine nopaline was detected in the tumours induced on test plants – but not on eucalyptus plants. Nopaline was degraded by the 20 pathogenic isolates that were also sensitive to agrocin 84, indicating the presence of a nopaline-type pTi in these strains. The chromosomal region encoding the 16S rRNA was analyzed in a sub-population of the pathogenic agrobacterial isolates. The analyzed strains were found to belong to the ribogroup of the reference strain B6. Interestingly, Eucalyptus camaldulensis and Eucalyptus cladocalyx grown in the same nursery and in the same soil substrate developed no galls. 相似文献
93.
The idea that landscape has been created by human activities on a biophysical basis allows for clear cause–effect reasoning.
However, landscape planning and management practice learns that it is impossible to neglect the social perception of landscape,
i.e. the ways people think about nature and landscape. It is the result of social research and human sciences of the last
decade that a differentiation in views of nature and landscape can be identified in the different groups of social actors
in the landscape. Case studies from France and the Netherlands show a marked change in values attributed to nature and landscape
in the end of the last century. Social demand for landscape is growing and a shift from a functional image of nature and landscape
to a more hedonistic image like the Arcadian and wilderness images has taken place. Comparing the Netherlands with France
and rural with urban inhabitants, the influence of urbanisation is evident in this process. It is further shown that images
of nature vary considerably between for example farmers, urban residents, hunters and conservationists. The way people perceive
landscape seems determined by their functional ties with the landscape and the social praxis in which they encounter the landscape.
It is concluded that the concept of landscape is nearer to the lifeworld of people than the abstract notions of nature and
biodiversity. This implies a big challenge both for national and international landscape policies and for local landscape
management initiatives to be developed, taking into due consideration both the material and immaterial nature of landscape. 相似文献
94.
Comparison of efficacy and safety of paste formulations of firocoxib and phenylbutazone in horses with naturally occurring osteoarthritis 总被引:1,自引:0,他引:1
Doucet MY Bertone AL Hendrickson D Hughes F Macallister C McClure S Reinemeyer C Rossier Y Sifferman R Vrins AA White G Kunkle B Alva R Romano D Hanson PD 《Journal of the American Veterinary Medical Association》2008,232(1):91-97
OBJECTIVE: To compare efficacy and safety of paste formulations of firocoxib and phenylbutazone in horses with naturally occurring osteoarthritis. DESIGN: Randomized controlled clinical trial. ANIMALS: 253 client-owned horses with naturally occurring osteoarthritis. PROCEDURES: Horses were treated with firocoxib (0.1 mg/kg [0.045 mg/lb], PO, q 24 h) or phenylbutazone (4.4 mg/kg [2 mg/lb], PO, q 24 h) for 14 days. Physical examinations and lameness evaluations were performed prior to treatment and after 7 and 14 days. Clinical improvement was defined as a reduction of at least 1 lameness grade or a combined reduction of at least 3 points in scores for pain during manipulation or palpation, joint swelling, joint circumference, and range of motion. RESULTS: Proportion of horses clinically improved on day 14 for the firocoxib group (104/123 [84.6%]) was not significantly different from the proportion for the phenylbutazone group (103/119 [86.6%]). Proportion of horses that were improved on day 14 was significantly greater for horses treated with firocoxib than for horses treated with phenylbutazone with regard to score for pain on manipulation or palpation (P = 0.028), joint circumference score (P = 0.026), and range of motion score (P = 0.012), but not for overall lameness score or joint swelling score. No direct treatment-related adverse effects were detected during the study. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that overall clinical efficacy of a paste formulation of firocoxib in horses with naturally occurring osteoarthritis was comparable to efficacy of a paste formulation of phenylbutazone. 相似文献
95.
Ververken C Geysen D Loots K Janssens ME Guisez Y Goddeeris BM 《Veterinary immunology and immunopathology》2008,124(3-4):253-263
East Coast fever, an acute lymphoproliferative disease of cattle, is caused by the apicomplexan parasite Theileria parva. Protective immunity is mediated by CD8(+) cytotoxic T lymphocytes directed against schizont-infected cells. The polymorphic immunodominant molecule, although an antibody-inducing surface molecule of the schizont, has been hypothesized to play a role in protective immunity. In order to evaluate the immunogenicity of PIM for inducing CTL, cattle were immunized with PIM in isolation from other T. parva antigens, forcing the presentation of PIM-derived epitopes on the MHC class I molecules. Although parasite-specific cytotoxicity was induced in both vaccinated animals, their immune response was clearly different. One animal generated MHC-restricted parasite-specific CTL against PIM while the other calf exhibited a strong PIM-specific proliferative response but non-MHC-restricted parasite-specific cytotoxicity. Only calf 1 survived a lethal sporozoite challenge. This DNA immunization technique with an antigen in isolation of CTL-immunodominant antigens might open possibilities for directing CTL responses against predefined antigens, such as strain cross-reacting CTL antigens. 相似文献
96.
97.
98.
Chaste Emeline Girardin Martin P. Kaplan Jed O. Bergeron Yves Hély Christelle 《Landscape Ecology》2019,34(2):403-426
Landscape Ecology - The Canadian boreal forest provides valuable ecosystem services that are regionally and globally significant. Despite its importance, the future of the Canadian boreal forest is... 相似文献
99.
Denis Faure Yves Dessaux 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(3):353-365
Quorum sensing is a regulatory mechanism that connects gene expression to cell density in bacteria. Amongst proteobacteria,
numerous functions are regulated in this way, including pathogenicity in the Enterobacteriaceae genus Pectobacterium. In Pectobacterium, the signalling molecules involved in this regulatory process belong to the N-acyl-homoserine lactone class. Over the last
6 years, various studies have shown that these signal molecules could be degraded by other bacteria or by plant and animal
cells, opening the path to innovative biocontrol strategies. This review explores the various determinants of pathogenicity
in Pectobacterium and describes approaches that have been developed to quench the quorum-sensing-dependent pathogenicity in Pectobacterium. These approaches range from signal degradation by physicochemical constraints to the identification of signal-sensing inhibitors
and from the identification of enzymes degrading acyl-homoserine lactones to the construction of transgenic plants tolerant
to Pectobacterium. 相似文献
100.
Scale-dependent determinants of heterogeneity in fire frequency in a coniferous boreal forest of eastern Canada 总被引:1,自引:0,他引:1
Despite the recognized importance of fire in North American boreal forests, the relative importance of stochastic and determinist
portions of intra-regional spatial variability in fire frequency is still poorly understood. The first objective of this study
is to identify sources of spatial variability in fire frequency in a landscape of eastern Quebec’s coniferous boreal forest.
Broad-scale environmental factors considered included latitude, longitude, human activities and belonging to a given bioclimatic
domain, whereas fine-scale factors included slope, position on the slope, aspect, elevation, surficial deposit and drainage.
The average distance to waterbodies was also considered as a potential intermediate-scale source of variability in fire frequency.
In order to assess these environmental factors’ potential influence, they were incorporated into a proportional hazard model,
a semi-parametric form of survival analysis. We also used a digital elevation model in order to evaluate the dominant aspect
within neighborhoods of varying sizes and successively incorporated these covariates into the proportional hazard model. We
found that longitude significantly affects fire frequency, suggesting a maritime influence on fire frequency in this coastal
landscape. We also found that position on the slope was related to fire frequency since hilltops and upperslopes were subject
to a lower fire frequency. Dominant aspect was also related to fire frequency, but only when characterized within a neighborhood
delimited by 4,000 to 10,000-m radii (5,027–31,416 ha). A 2–6-fold variation in fire frequency can be induced by geographic
and topographic contexts, suggesting a substantial intra-regional heterogeneity in disturbance regime with potential consequences
on forest dynamics and biodiversity patterns. Implications for forest management are also briefly discussed.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献