首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5582篇
  免费   306篇
  国内免费   5篇
林业   406篇
农学   207篇
基础科学   17篇
  1473篇
综合类   305篇
农作物   402篇
水产渔业   524篇
畜牧兽医   2018篇
园艺   130篇
植物保护   411篇
  2024年   6篇
  2023年   62篇
  2022年   80篇
  2021年   243篇
  2020年   240篇
  2019年   289篇
  2018年   230篇
  2017年   226篇
  2016年   222篇
  2015年   176篇
  2014年   242篇
  2013年   378篇
  2012年   454篇
  2011年   455篇
  2010年   258篇
  2009年   210篇
  2008年   371篇
  2007年   379篇
  2006年   270篇
  2005年   224篇
  2004年   190篇
  2003年   176篇
  2002年   168篇
  2001年   33篇
  2000年   28篇
  1999年   30篇
  1998年   18篇
  1997年   19篇
  1996年   18篇
  1995年   14篇
  1994年   17篇
  1993年   14篇
  1992年   10篇
  1991年   7篇
  1990年   16篇
  1989年   12篇
  1988年   7篇
  1987年   9篇
  1986年   10篇
  1985年   12篇
  1984年   13篇
  1983年   8篇
  1982年   5篇
  1980年   5篇
  1977年   4篇
  1973年   5篇
  1972年   4篇
  1969年   4篇
  1966年   5篇
  1955年   2篇
排序方式: 共有5893条查询结果,搜索用时 31 毫秒
61.
Duodenal and jejunal resections were performed in a cat with septic peritonitis due to small intestinal perforations by a linear foreign body. Three days later jejunal resection and anastomosis were repeated due to dehiscence of the anastomosis site. This segment of intestine was exteriorized through the body wall and managed with bandages for 5 days before it was surgically replaced into the abdomen. The cat made a full recovery.  相似文献   
62.
63.
64.
65.
A 5.5‐year‐old, intact male Rottweiler dog was admitted with a history of multifocal nodular tongue lesions which progressively deteriorated during the previous year. Physical examination revealed several reddish nodules with central depression on the surface of the tongue in an otherwise healthy dog. Clinicopathologic abnormalities included eosinophilia and hyperproteinemia. Lingual nodule cytopathology, histopathology, and immunohistochemistry revealed Leishmania spp. amastigotes and a severe granulomatous glossitis. The dog was also seroreactive to L infantum antigens by an indirect immunofluorescence assay. Clinical reevaluation 3 months after the institution of treatment with allopurinol and miltefosine indicated that the nodular lesions had completely regressed. In endemic areas, lingual nodular lesions may rarely be the sole clinical sign of canine leishmaniosis. Standard medical treatment may provide an excellent prognosis.  相似文献   
66.
Blood transfusions in veterinary medicine have become increasingly more common and are now an integral part of lifesaving and advanced treatment in small and large animals. Important risks associated with transfusion of blood products include the transmission of various infectious diseases. Several guidelines suggest what infectious agents to screen for in canine and feline transfusion medicine. However, while the risk of bacterial contamination of blood products during storage and administration has not been documented in veterinary medicine, it has emerged as a cause of morbidity and mortality in human transfusion medicine. Clinical experience shows that the majority of blood component bacterial contaminations are caused by only a few species. Unlike other types of bacteria, psychrotolerant species like Pseudomonas spp. and Serratia spp. can proliferate during the storage of blood units at 4°C from a very low titer at the time of blood collection to a clinically significant level (> 105 CFU/mL) causing clinical sepsis resulting from red blood cell concentrate transfusions in human medicine. The purpose of this report was to describe the detection and quantification procedures applied in 4 cases of bacterial contamination of canine and feline blood units, which suggest the need for further investigations to optimize patients’ safety in veterinary transfusion medicine.  相似文献   
67.
OBJECTIVE: To assess the effect of maternal cells or cellular components on neonatal immune responses to intracellular pathogens in calves. ANIMALS: 15 Holstein calves. PROCEDURES: Calves were fed whole colostrum, frozen colostrum, or cell-free colostrum within 4 hours after birth. Leukocytes were obtained from calves before feeding colostrum and 1, 2, 7, 14, 21, and 28 days after ingestion. Proliferative responses against bovine viral diarrhea virus (BVDV) and mycobacterial purified protein derivatives were evaluated. Dams received a vaccine containing inactivated BVDV, but were not vaccinated against mycobacterial antigens. RESULTS: All calves had essentially no IgG in circulation at birth, but comparable and substantial concentrations by day 1. Calves that received whole colostrum had enhanced responses to BVDV antigen 1 and 2 days after ingestion of colostrum. In contrast, calves that received frozen colostrum or cell-free colostrum did not respond to BVDV. No differences were identified among the 3 groups in response to mycobacterial antigens. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that transfer of live maternal cells from colostrum to neonatal calves enhanced responses to antigens against which the dams had previously responded (BVDV), but not to antigens to which the dams were na?ve (mycobacterial purified protein derivatives). Results suggested that cell-mediated immune transfer to neonates can be enhanced by maternal vaccination.  相似文献   
68.
Twenty-eight research dogs were enrolled to determine the prevalence of salmonellae shedding after consumption of 1 Salmonella-contaminated commercial raw food diet meal. Sixteen dogs were exposed to Salmonella-contaminated commercial raw food diets and 12 to Salmonella-free commercial raw food diets. Seven of the exposed dogs shed salmonellae 1-7 days after consumption of Salmonella-contaminated raw food diets. None of the dogs fed Salmonella-free diets shed salmonellae. No clinical signs were observed in either group. Five of the 7 dogs shed the same serotypes as those recovered from food samples used for feeding. Results showed the same serotypes and antimicrobial resistance pattern in 2 of the 7 shedders. Dogs fed Salmonella-contaminated raw food diets can shed salmonellae and may, therefore, be a source of environmental contamination potentially leading to human or animal illness.  相似文献   
69.
OBJECTIVE: To evaluate use of electroacupuncture combined with standard Western medical treatment versus Western medical treatment alone for treatment of thoracolumbar intervertebral disk disease in dogs. DESIGN: Prospective controlled study. ANIMALS: 50 dogs with signs of thoracolumbar intervertebral disk disease. PROCEDURES: Dogs were randomly allocated to 1 of 2 treatment groups and classified as having grade 1 to 5 neurologic dysfunction. Dogs in group 1 received electroacupuncture stimulation combined with standard Western medical treatment; those in group 2 received only standard Western medical treatment. A numeric score for neurologic function was evaluated at 4 time points to evaluate effects of treatments. RESULTS: Time (mean +/- SD) to recover ambulation in dogs with grade 3 and 4 dysfunction in group 1 (10.10 +/- 6.49 days) was significantly lower than in group 2 (20.83 +/- 11.99 days). Success (able to walk without assistance) rate for dogs with grade 3 and 4 dysfunction in group 1 (10/10 dogs) was significantly higher than that of similarly affected dogs in group 2 (6/9 dogs). Dogs without deep pain perception (grade 5 dysfunction) had a success (recovery of pain sensation) rate of 3 of 6 and 1 of 8 in groups 1 and 2, respectively, but the difference was not significant. Overall success rate (all dysfunction grades) for group 1 (23/26; 88.5%) was significantly higher than for group 2 (14/24; 58.3%). CONCLUSIONS AND CLINICAL RELEVANCE: Electroacupuncture combined with standard Western medical treatment was effective and resulted in shorter time to recover ambulation and deep pain perception than did use of Western treatment alone in dogs with signs of thoracolumbar intervertebral disk disease.  相似文献   
70.
Horseshoeing is a common practice, but effects on the hoof wall are poorly understood. Strain gauges were used to document and compare hoof behavior in vitro during flat weight bearing and after artificial heel elevation. Ten front limbs of Thoroughbred race horses, shod with conventional flat shoes, were used. Eight strain gauges were symmetrically distributed around the toe, quarters, and heels. Each limb was mounted to a testing machine (Kratos K5002; Kratos Dynamômetros, Ltda., Cotia-SP-Brazil) and subjected to a load equivalent to 30% of the donor's body weight. Strains (μ) were acquired by means of a computerized system and the results compared using Friedman and Wilcoxon statistical tests. There was greater strain variation when the heels were elevated. Compression predominated during flat weight bearing, with a tendency to horizontal traction after heel elevation. The changes in strain caused by heel elevation were not always symmetrical. Elevation of the heels tensed the toe and the medial quarter horizontally, increased load at the posterior portion of the hoof capsule, and hindered its expansion.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号