全文获取类型
收费全文 | 76866篇 |
免费 | 4333篇 |
国内免费 | 41篇 |
专业分类
林业 | 3362篇 |
农学 | 2587篇 |
基础科学 | 507篇 |
9286篇 | |
综合类 | 12275篇 |
农作物 | 2980篇 |
水产渔业 | 3690篇 |
畜牧兽医 | 40302篇 |
园艺 | 932篇 |
植物保护 | 5319篇 |
出版年
2018年 | 1037篇 |
2017年 | 1152篇 |
2016年 | 1071篇 |
2015年 | 891篇 |
2014年 | 1119篇 |
2013年 | 2912篇 |
2012年 | 2083篇 |
2011年 | 2469篇 |
2010年 | 1685篇 |
2009年 | 1698篇 |
2008年 | 2498篇 |
2007年 | 2353篇 |
2006年 | 2170篇 |
2005年 | 2098篇 |
2004年 | 1964篇 |
2003年 | 2092篇 |
2002年 | 1929篇 |
2001年 | 2334篇 |
2000年 | 2277篇 |
1999年 | 1818篇 |
1998年 | 755篇 |
1997年 | 801篇 |
1996年 | 716篇 |
1995年 | 891篇 |
1994年 | 770篇 |
1993年 | 777篇 |
1992年 | 1554篇 |
1991年 | 1696篇 |
1990年 | 1653篇 |
1989年 | 1663篇 |
1988年 | 1525篇 |
1987年 | 1498篇 |
1986年 | 1574篇 |
1985年 | 1500篇 |
1984年 | 1309篇 |
1983年 | 1109篇 |
1982年 | 794篇 |
1979年 | 1202篇 |
1978年 | 918篇 |
1977年 | 871篇 |
1976年 | 836篇 |
1975年 | 858篇 |
1974年 | 1066篇 |
1973年 | 1098篇 |
1972年 | 1044篇 |
1971年 | 980篇 |
1970年 | 952篇 |
1969年 | 933篇 |
1968年 | 772篇 |
1967年 | 870篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
Reasons for performing study: Tears of the radial head of the deep digital flexor (DDF) have not previously been documented. Objectives: To describe the presentation, clinical, ultrasonographic and tenoscopic features associated with tears of the radial head of the DDF and to report the results of treatment. Hypotheses: Tears of the radial head of the DDF cause lameness and distension of the carpal sheath of the digital flexor tendons. Removal of disrupted tissue that is extruded into the sheath can result in clinical resolution and restoration of function. Methods: Case records and diagnostic images of horses in which tearing of the radial head of the DDF was diagnosed were reviewed retrospectively and follow‐up information obtained. Results: Eleven cases were identified. Clinical, ultrasonographic and tenoscopic commonality was recorded and treatment techniques were documented. All cases returned post operatively to pre‐injury levels of work. Conclusion: Tearing of the radial head of the DDF is a clinical entity with consistent diagnostic features. Tenoscopic removal of the torn tissue is associated with a good outcome. Potential relevance: Clinicians evaluating lame horses should include tearing of the radial head of the DDF as a differential diagnosis in animals with distended carpal sheaths. Tenoscopic surgery is a recommended treatment. 相似文献
932.
Nakamura RK Tompkins E Braasch EL Martinez JG Bianco D 《The Journal of small animal practice》2012,53(3):155-160
Objective: To evaluate the hand hygiene (HH) practices among veterinary technicians (VT) and veterinary support staff (VSS) in small animal private practice. Methods: This was a prospective questionnaire‐based study involving 182 VT and VSS from 18 small animal hospitals in the USA. Questions asked included gender, number of animals handled per work shift, frequency of hand washing, reason for not washing more frequently, most common available hand washing agent, education regarding the importance of HH and frequency of ring wearing. Results: Less than half of the respondents [76 of 182 (41·7%)] reported washing their hands regularly between handling patients and 154 of 182 (85·6%) believed they should have washed more frequently. The most commonly employed HH agent was hand soap [154 of 182 (84·6%)] and the most common reason cited for not washing more frequently was being too busy [132 of 182 (72·5%)]. Only 96 of 182 (52·7%) respondents were educated by doctors at their hospital regarding the importance of HH. Clinical Significance: The HH practices among VT and VSS in small animal private practice is poor. Hand soap was the most commonly employed agent among respondents in this study. Education of VT and VSS regarding the importance of HH requires improvement. 相似文献
933.
934.
935.
936.
937.
Michel's medium as a preservative for immunofluorescent staining of cutaneous biopsy specimens in dogs and cats 总被引:2,自引:0,他引:2
Paired 3-mm skin biopsy specimens from 24 dogs and 11 cats with suspected autoimmune dermatopathies were stained with fluorescein-conjugated antisera. In each case, 1 specimen was immediately embedded in optimum cutting temperature compound, quick frozen to -30 C, processed, stained, and examined. The other sample was placed in Michel's transport medium, held for 7 days, and then processed, stained, and examined. The location, quality, and intensity of immunofluorescent staining (when positive) were then compared in the 2 specimens. There were no differences in the staining patterns between the specimens processed immediately and those held in Michel's medium, thus demonstrating the validity of preserving canine and feline skin biopsy specimens in Michel's medium for immunofluorescent examination. 相似文献
938.
939.
H.W. Brooks G.A. Hall A.J. Wagstaff A.R. Michell 《Veterinary journal (London, England : 1997)》1998,155(3):263-274
This paper examines the possibility that treatment of diarrhoea with conventional oral rehydration solutions (ORSs) may be detrimental to villus structure by imposing nutrient deprivation and that such detrimental effects may be reduced or avoided by using a nutrient ORS. A conventional WHO-type ORS (W) was compared with two nutrient solutions (N and G) both containing high glucose concentrations and the latter containing glutamine; their effects on enteric structure were assessed by morphometric analysis of samples obtained from diarrhoeic calves after 96h treatment. Comparisons were also made with samples from controls and diarrhoeic calves at the stage where oral rehydration would have begun in the treated groups. As in our previous ORS studies, diarrhoea was induced with enterotoxigenic Escherichia coli (09:K30:K99). We measured villus length and width, crypt depth and width and calculated villus surface area in proximal, mid and distal small intestine (PSI, MSI, DSI), using standard morphometric techniques. Proximal and distal spiral colon samples (PC, DC) were examined for crypt depth and width; mitoses per crypt were counted in samples from all regions. Non-diarrhoeic calves showed the expected gradient of villus length through PSI, MSI and DSI, hence data for each region are normalized as a percentage of the control value for that region. PSI showed the greatest loss of villus length and surface area (50%) with diarrhoea. In MSI and DSI the villus loss was greater with solution W and N or G, as were increased mitoses and crypt depth. Crypt depth and mitoses also increased in the colon with solution W. Colonic crypt width increased with diarrhoea and conventional oral rehydration but less so with G; there is reason to believe that such changes have functional significance. Crypt changes in colon, MSI and DSI were least with solution G. The changes developing in diarrhoeic calves prior to treatment were thus less apparent in those treated with a nutritional ORS, particularly if it contained glutamine. 相似文献
940.