全文获取类型
收费全文 | 101669篇 |
免费 | 5669篇 |
国内免费 | 317篇 |
专业分类
林业 | 4503篇 |
农学 | 3619篇 |
基础科学 | 755篇 |
13132篇 | |
综合类 | 16159篇 |
农作物 | 3854篇 |
水产渔业 | 5063篇 |
畜牧兽医 | 52358篇 |
园艺 | 1288篇 |
植物保护 | 6924篇 |
出版年
2019年 | 953篇 |
2018年 | 1661篇 |
2017年 | 1789篇 |
2016年 | 1629篇 |
2015年 | 1391篇 |
2014年 | 1766篇 |
2013年 | 4126篇 |
2012年 | 3055篇 |
2011年 | 3647篇 |
2010年 | 2523篇 |
2009年 | 2599篇 |
2008年 | 3706篇 |
2007年 | 3374篇 |
2006年 | 3284篇 |
2005年 | 2941篇 |
2004年 | 2993篇 |
2003年 | 2962篇 |
2002年 | 2740篇 |
2001年 | 3359篇 |
2000年 | 3326篇 |
1999年 | 2633篇 |
1998年 | 1210篇 |
1997年 | 1154篇 |
1996年 | 1057篇 |
1995年 | 1183篇 |
1994年 | 1122篇 |
1993年 | 983篇 |
1992年 | 2058篇 |
1991年 | 2184篇 |
1990年 | 2213篇 |
1989年 | 2098篇 |
1988年 | 1954篇 |
1987年 | 1841篇 |
1986年 | 1933篇 |
1985年 | 1780篇 |
1984年 | 1504篇 |
1983年 | 1354篇 |
1979年 | 1474篇 |
1978年 | 1171篇 |
1977年 | 1023篇 |
1976年 | 988篇 |
1975年 | 1046篇 |
1974年 | 1163篇 |
1973年 | 1239篇 |
1972年 | 1183篇 |
1971年 | 1036篇 |
1970年 | 1056篇 |
1969年 | 1088篇 |
1967年 | 955篇 |
1966年 | 913篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Presentation,clinical pathological and post‐mortem findings in three related Scottish terriers with ligneous membranitis 下载免费PDF全文
S. L. Mason C. Fisher L. Ressel N. X. Bommer L. M. Buckley T. Nuttall 《The Journal of small animal practice》2016,57(5):271-276
Ligneous conjunctivitis and gingivitis were diagnosed in three related Scottish terrier dogs presented for investigation of severe conjunctivitis and respiratory signs. Hypoplasminogenaemia was confirmed in one of the three affected dogs. Supportive treatment was not effective, and the dogs died or were euthanased because of the disease. Post‐mortem analysis of two of the dogs revealed multiple abnormalities including severe proliferative fibrinous lesions affecting the conjunctiva, gingiva, trachea, larynx and epicardium and multiple fibrous adhesions throughout the thoracic and abdominal cavities. One dog had internal hydrocephalus and lacked a cerebellar vermis. Ligneous membranitis was confirmed on histopathology. This is a rare condition in dogs but an important differential diagnosis for severe conjunctivitis and gingivitis. 相似文献
962.
963.
964.
Influence of Breed Size,Age, Fecal Quality,and Enteropathogen Shedding on Fecal Calprotectin and Immunoglobulin A Concentrations in Puppies During the Weaning Period 下载免费PDF全文
965.
966.
967.
Pees MC Kiefer I Ludewig EW Schumacher JP Krautwald-Junghanns ME Oechtering GU 《American journal of veterinary research》2007,68(4):428-434
OBJECTIVE: To evaluate the use of computed tomography (CT) for detection of pneumonia in snakes. ANIMALS: 8 clinically normal Indian pythons (Python molurus) and 5 pythons with evidence of respiratory tract disease. PROCEDURES: Preliminary examinations (clinical examination, conventional radiography, and microbiologic examination of a transtracheal wash sample) were performed. The lungs of each snake were then examined by use of CT performed in accordance with a standardized protocol. Structures of the lungs were assessed, and thickness and attenuation of the parenchyma were determined. RESULTS: It was possible to assess lung parenchyma in all pythons. Mean +/- SD attenuation in healthy pythons was -744.4 +/- 47.1 Hounsfield units. Significant differences were not evident between the right and left lungs or among measurement areas within a lung. In all Indian pythons with clinical signs of dyspnea and microbiologic detection of pathogens, hyperattenuation of the alveolar tissue was evident. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of the results revealed the benefit of CT for use in the diagnosis of pneumonia in snakes. A standardized protocol and reference values were established as a basis for CT assessment of the lungs of snakes. 相似文献
968.
OBJECTIVE: To determine historical, physical, and microbiologic findings in horses with limb cellulitis and identify factors associated with short- and long-term outcome. DESIGN: Retrospective case series. ANIMALS: 44 horses with limb cellulitis. PROCEDURES: Information obtained from medical records included use, history, affected limb, diagnostic procedures, treatment, and short-term outcome. Long-term follow-up information was obtained by means of a telephone survey. RESULTS: Twenty-four horses had primary cellulitis, and 18 of the 24 (75%) had a hind limb affected. Results of microbiologic culture were positive for all 20 horses with primary cellulitis from which specimens were obtained, with coagulase-positive Staphylococcus spp recovered from 12 of the 20. Short-term survival rate was 67% (16/24) for horses with primary cellulitis; 7 of the 9 horses available for long-term follow-up were being used for their intended use, and 4 had had a recurrence. Results of microbiologic culture were positive for 13 of the 16 (81%) horses with secondary cellulitis from which specimens were obtained. Short-term survival rate for horses with secondary cellulitis was 90% (18/20). Eleven of the 17 horses available for long-term follow-up were being used for their intended use; 2 had had a recurrence. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that cellulitis can be a life-threatening condition in horses. Horses that were febrile at admission or that developed laminitis were significantly less likely to survive. The prognosis for return to function was guarded, and recurrence was a potential concern. 相似文献
969.
A 4-year-old Arab mare was diagnosed with disseminated cryptococcosis, including osteomyelitis of the proximal phalanx of the left hind limb, osteomyelitis with associated soft tissue granuloma of a rib and disseminated, large cryptococcal nodules in the lungs. The lesion in the dorsoproximal aspect of the proximal phalanx had a large area of cortical lysis with spiculated periosteal new bone and extensive soft tissue swelling. The affected rib had a pathological fracture. Cryptococcal osteomyelitis has not been previously reported in horses but should be considered as a differential diagnosis, particularly in endemic regions. 相似文献
970.
Evason MD Taylor SM Bebchuk TN 《The Canadian veterinary journal. La revue veterinaire canadienne》2007,48(3):296-298
A 4.5-month-old, male domestic shorthair was presented with bilateral femoral fractures after falling from a low height. Radiographs revealed reduced radio-opacity and thin cortices of all long bones. A presumptive diagnosis of osteodystrophy, secondary to osteogenesis imperfecta, was made on postmortem examination. 相似文献