全文获取类型
收费全文 | 597篇 |
免费 | 32篇 |
国内免费 | 4篇 |
专业分类
林业 | 30篇 |
农学 | 15篇 |
109篇 | |
综合类 | 97篇 |
农作物 | 26篇 |
水产渔业 | 39篇 |
畜牧兽医 | 273篇 |
园艺 | 13篇 |
植物保护 | 31篇 |
出版年
2023年 | 5篇 |
2021年 | 5篇 |
2020年 | 13篇 |
2019年 | 7篇 |
2018年 | 15篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 15篇 |
2013年 | 39篇 |
2012年 | 31篇 |
2011年 | 33篇 |
2010年 | 19篇 |
2009年 | 17篇 |
2008年 | 21篇 |
2007年 | 26篇 |
2006年 | 23篇 |
2005年 | 24篇 |
2004年 | 24篇 |
2003年 | 26篇 |
2002年 | 27篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 7篇 |
1996年 | 8篇 |
1995年 | 14篇 |
1994年 | 8篇 |
1993年 | 11篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1977年 | 4篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1969年 | 3篇 |
1967年 | 3篇 |
1946年 | 3篇 |
1944年 | 8篇 |
1942年 | 3篇 |
排序方式: 共有633条查询结果,搜索用时 15 毫秒
81.
82.
83.
Joe P. Morgan DVM Vet med dr Takayoshi Miyabayashi BVS MS 《Veterinary radiology & ultrasound》1988,29(2):72-77
A group of 160 Beagles were studied radiographically to determine the pattern of degenerative changes within the vertebral column, especially involving the intervertebral discs. The normal radiographic appearance of both disc and surrounding vertebrae is described. Disc space narrowing and calcification of discal tissues provide radiographic patterns that assist in diagnosis and prognosis. Because of the older age of the dogs, severe degeneration of the endplates with marked instability between vertebral segments was seen. 相似文献
84.
Weese JS Caldwell F Willey BM Kreiswirth BN McGeer A Rousseau J Low DE 《Veterinary microbiology》2006,114(1-2):160-164
There are increasing reports of methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization in horses and evidence that MRSA can be transmitted between horses and humans. The objective of this study was to investigate reports of skin infection in personnel working with a foal with community-associated MRSA colonization and subsequent infection. Clinical diagnostic specimens were collected from individuals reporting skin lesions following contact with the affected foal. Nasal and groin screening swabs were collected from other veterinary personnel that attended a voluntary screening clinic. MRSA skin infections were identified in three neonatal intensive care unit personnel. Nasal colonization was subsequently identified in 10/103 (9.7%) other veterinary hospital personnel. Isolates were indistinguishable by pulsed field gel electrophoresis, classified as Canadian epidemic MRSA-5, possessed SCCmecIV, were negative for the Panton-Valentine leukocidin and were multidrug resistant. Transmission to veterinary personnel despite short-term contact with standard protective barriers highlights the potential importance of MRSA as an emerging zoonotic pathogen, and indicates that further evaluation of interspecies transmission of MRSA and means to prevent zoonotic infection are required. 相似文献
85.
86.
The future of radiography will be digital. In exotic pet radiography, where some of the animals have a very low body weight and anatomic structures can be small, detail rendition plays an important feature in image quality. Veterinarians should be familiar with the technical principles, image quality criteria, and radiation exposure issues associated with the various types of digital systems currently available. This article discusses basic principles of digital radiography, technical solutions, and selected parameters characterizing detectors, processing, and monitors. An overview of reported experiences is given, and results from experimental clinical studies are reviewed to evaluate the current options and limitations in applying digital radiography to exotic pet medicine. 相似文献
87.
The urban forest of three arctic and near-arctic cities (Murmansk in Russia, Nuuk in Greenland, and Reykjavik in Iceland) were surveyed to determine tree species composition and structure. Interviews with local authorities were conducted to learn about the history of urban tree planting. The urban forests of all three cities were composed of a limited number of trees and tree species due to abiotic constraints of the arctic and near-arctic environment. These limitations include: low temperature, short growing season, high wind velocity and permafrost. A total of 28 species were observed in the three cities. Only three of these (Alnus incana (L.) Moench, Picea abies (L.) Karst., Betula pubescens Ehrh., and Salix glauca L.) were observed in all three of the cities. Planting designs that created windbreaks for pedestrians were common along streets in Murmansk and Reykjavik. Street trees have not yet been introduced in Nuuk, but trees were found in cemeteries, parks, and on private property. Older portions of cemeteries in all three cities were characterized by trees planted directly on graves. These grave trees were the first trees to be introduced in these cities. Subsequently, ‘trial and error’ was used by local residents to plant trees. Much of these plantings failed. In recent times arboreta were established near all three cities to identify species suited for planting under arctic and near-arctic conditions. Trees identified in these test gardens are now being planted in Murmansk and Reykjavik. 相似文献
88.
Variations in intracranial dural venous sinus anatomy have been widely reported in humans, but there have been no studies reporting this in dogs. The purpose of this retrospective study was to describe variations in magnetic resonance (MR) venographic anatomy of the dorsal dural venous sinus system in a sample population of dogs with structurally normal brains. Medical records were searched for dogs with complete phase contrast, intracranial MR venograms and a diagnosis of idiopathic epilepsy. Magnetic resonance venograms were retrieved for each dog and characteristics of the dorsal dural sinuses, symmetry of the transverse sinuses and other anatomic variations were recorded. A total of 51 dogs were included. Transverse sinus asymmetry was present in 58.8% of the dogs, with transverse sinus hypoplasia seen in 39.2%, and aplasia in 23.5% of dogs. For 70.6% of dogs, at least one anatomic variation in the dorsal sagittal sinus was observed, including deviation from the midline (33.3%) and collateral branches from either the dorsal sagittal sinus or dorsal cerebral veins (54.9%). In 5 dogs (9.8%) a vessel was also identified running from the proximal transverse sinus to the distal sigmoid sinus, in a similar location to the occipital sinus previously reported in children. Findings from this study indicated that, as in humans, anatomic variations are common in the intracranial dural venous sinus system of dogs. These anatomic variations should be taken into consideration for surgical planning or diagnosis of cerebrovascular disease. 相似文献
89.
90.
D.W. Caldwell M.R.C.V.S. 《New Zealand veterinary journal》2013,61(8):167-172
Extract The development of the commercial operation of artificial insemination (A.I.) in New Zealand has in the main been associated with the New Zealand Dairy Board and the affiliated Herd Improvement Associations with a relatively minor contribution from the practising profession. 相似文献