全文获取类型
收费全文 | 5820篇 |
免费 | 516篇 |
专业分类
林业 | 48篇 |
农学 | 25篇 |
131篇 | |
综合类 | 77篇 |
农作物 | 26篇 |
水产渔业 | 39篇 |
畜牧兽医 | 5901篇 |
园艺 | 11篇 |
植物保护 | 78篇 |
出版年
2024年 | 7篇 |
2023年 | 93篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 186篇 |
2019年 | 23篇 |
2018年 | 133篇 |
2017年 | 152篇 |
2016年 | 105篇 |
2015年 | 154篇 |
2014年 | 246篇 |
2013年 | 289篇 |
2012年 | 238篇 |
2011年 | 270篇 |
2010年 | 196篇 |
2009年 | 270篇 |
2008年 | 210篇 |
2007年 | 154篇 |
2006年 | 133篇 |
2005年 | 130篇 |
2004年 | 210篇 |
2003年 | 207篇 |
2002年 | 225篇 |
2001年 | 166篇 |
2000年 | 126篇 |
1999年 | 122篇 |
1998年 | 177篇 |
1997年 | 187篇 |
1996年 | 161篇 |
1995年 | 162篇 |
1994年 | 142篇 |
1993年 | 156篇 |
1992年 | 177篇 |
1991年 | 148篇 |
1990年 | 194篇 |
1989年 | 134篇 |
1988年 | 116篇 |
1987年 | 145篇 |
1986年 | 59篇 |
1985年 | 81篇 |
1984年 | 84篇 |
1983年 | 80篇 |
1982年 | 38篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1961年 | 1篇 |
1955年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有6336条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
Kevin P. Winkler DVM DACVS Cathy L. Greenfield DVM MS DACVS 《Journal of Veterinary Emergency and Critical Care》2000,10(4):259-265
The purpose of this study was to identify prognostic indicators that may help to predict outcome in clinical cases of diffuse peritonitis treated with open peritoneal drainage. Medical records from 19 canine patients with generalized peritonitis treated with open peritoneal drainage between 1990 and 1996 were reviewed. The signalment, preoperative complete blood count (CBC), preoperative biochemical profiles, and number of days of open peritoneal drainage of surviving patients (n = 15) were compared to nonsurviving patients (n = 4). Significant differences were noted between the surviving and nonsurviving groups in the ALT (p = 0.02) and GGT (p = 0.01) values. Seventy-nine percent of the patients in this study survived. 相似文献
996.
OBJECTIVE: To clone the 5' end of type III collagen and describe its pattern of mRNA and protein expression in normal and healing tendons in horses. ANIMALS: 14 healthy adult horses. PROCEDURE: The tensile region of collagenase-injured superficial digital flexor tendons was harvested at intervals from 1 to 24 weeks after injury. Total RNA was reverse-transcribed into cDNA for cloning and sequencing of type III collagen. Equine-specific nucleic acid probes were developed and used for northern blot analysis and in situ hybridization. Type III collagen protein and cyanogen bromide-cleaved collagen peptides were assessedby gel electrophresis. RESULTS: Type III collagen mRNA expression and protein content increased immediately after injury and remained increased. Type III collagen was localized to the endotenon in normal tendon and in injured tendon at 1 week. At 8 and 24 weeks, expression became more widely distributed throughout the tendon parenchyma. Injured tendon contained 6 times more type I than type III collagen mRNA. Quantities of type III collagen protein were maximal in the first 4 weeks after injury (approx 33%) and then began to decrease. CONCLUSIONS AND CLINICAL RELEVANCE: Type III collagen expression is increased initially in endotenon and subsequently in parenchyma of healing tendon; however, type III remains the minor collagen throughout the healing process. The role of type III collagen in tendon healing is not fully elucidated. 相似文献
997.
Johnson L Gough J Spencer Y Hewinson G Vordermeier M Wangoo A 《Veterinary immunology and immunopathology》2006,111(3-4):219-229
Development of necrotic granulomas in response to Mycobacterium bovis infection in cattle is pathognomonic for bovine tuberculosis. Previously our laboratory reported on M. bovis granuloma classification by stage of lesion advancement within bovine lymph nodes and developed immunohistochemical markers to further characterize these granulomas. In this study of bovine lymph node granulomas we applied this classification system to assess the dynamics of vaccination challenge. Lymph nodes collected from cattle vaccinated with M. bovis bacillus Calmette-Guerin (BCG) and subsequently challenged with virulent M. bovis were compared to lymph nodes from unvaccinated, challenged cattle. Expression of interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), type I procollagen and cell marker identification of T cells, B cells, macrophages and WC1(+)gammadelta TCR+ cells were assessed. Granulomas formed in vaccinated cattle were greatly reduced in number, area, degree of necrosis and peripheral fibrosis and contained fewer Langhans' giant cells, acid fast bacilli, WC1(+)gammadelta TCR+ cells and less TGF-beta expression in comparison to controls. B cells clustered intensely along the outer granuloma margins within vaccinated calves, with significantly more IFN-gamma producing cells identified in the medullary regions of lymph nodes from BCG-vaccinated animals compared to unvaccinated controls. This may be indicative of immune activation and surveillance in regions not directly associated with ongoing disease. Lymph node evaluation using light microscopy and immunohistochemical markers is useful to assess the immune response and discriminate granulomas to determine vaccine efficacy and disease severity. 相似文献
998.
This report describes the diagnosis of a fracture of the greater tubercle of the humerus and successful repair with 2 cancellous bone screws in a 420 kg adolescent horse. 相似文献
999.
Kelly M. Tart DVM Danielle M. Babski DVM Justine A. Lee DVM DACVECC 《Journal of Veterinary Emergency and Critical Care》2010,20(3):319-329
Objective – To evaluate a clinical population of dogs diagnosed with presumptive aspiration pneumonia (AP) and determine diagnostic and treatment modalities contributing to survival. Design – Retrospective study. Setting – A university veterinary teaching hospital in an urban setting. Animals – One hundred and twenty‐five dogs with presumed AP treated from 2005 to 2008. Interventions – None. Measurements and Main Results – Dogs with presumptive AP identified by a review of medical records had an overall survival of 81.6% (102/125). Male large‐breed dogs (mean 24.9 kg; 82/125) were overrepresented and were more likely to develop AP in this study population. Recent anesthesia had been performed in 16% (20/125), and vomiting was reported in 64% (80/125). The most common radiographic findings were a predominantly alveolar pattern (187/272, [68.8%] total lung lobes) in the right middle lung lobe (80/115, [69.6%]). A mean of 2 lung lobes were involved radiographically, and the relationship between survival and the number of lung lobes affected was statistically significant (P=0.04). Neutrophilia with a left shift was common with no significant change on consecutive daily evaluations. The mean PaO2 was 77.7 mm Hg (SD, 17.5 mm Hg) (range, 40.7–100 mm Hg) with a median alveolar‐arterial gradient of 41.1 mm Hg (range, 8.1–81.8 mm Hg). In this study population, 37.6% (47/125) of dogs had microbial cultures performed and of these, 76.6% (36/47) were positive for growth; Escherichia coli (38.8%), Mycoplasma spp. (21.3%), Pasturella spp. (19.1%), and Staphylococcus spp. (17%) were the most common isolates in either single or multiagent infections. No treatment modality was statistically associated with increased survival. Colloid therapy was a negative prognostic indicator. Conclusions – In this study the overall prognosis for AP was good. Patients with only 1 affected lung lobe appeared more likely to survive. Supportive treatment modalities are warranted for the hospitalized patient, although no individual treatment method was found to be clearly superior to others. 相似文献
1000.
J.A. Hudson DVM PhD J.E. Steiss DVM PhD K.G. Braund BVSc MVSc PhD FRCVS M. Toivio-Kinnucan PhD 《Veterinary radiology & ultrasound》1996,37(4):302-312
Ultrasonography was performed on sciatic, tibial and/or peroneal nerves and interosseous muscles in 7 dogs using a ultrasound machine with a 7.5 MHz linear array transducer. A tibial nerve was transected near the distal aspect of the bellies of the gastroenemius muscle. Serial neurologic examinations, electromyography, and ultrasonography were performed before and after surgery. Dogs were euthanized at variable intervals and histopathology performed on nerve samples. In sagittal images, normal nerves had hyperechoic walls with multiple internal linear echoes. In transverse images, the nerves were round or oval hyperechoic structures with internal punctate echoes. After transection, the proximal stump was consistently seen whereas the distal stump and nerve were harder to identify. Neuromas were present in all 5 dogs followed beyond 2 days and appeared as hypoechoic bulbous swellings most apparent at 3 weeks after surgery. Only 1 dog developed a neuroma large enough to be considered of potential clinical significance. Four dogs were followed beyond 2 months. Regeneration was evidenced by a steady growth of nerve with an irregular outline (2 dogs) or by a knobby connection between the proximal and distal stumps (1 dog). Regeneration was not detected in 1 dog. 相似文献