全文获取类型
收费全文 | 232篇 |
免费 | 6篇 |
专业分类
林业 | 18篇 |
农学 | 3篇 |
21篇 | |
综合类 | 22篇 |
农作物 | 17篇 |
水产渔业 | 26篇 |
畜牧兽医 | 115篇 |
园艺 | 2篇 |
植物保护 | 14篇 |
出版年
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 9篇 |
2012年 | 10篇 |
2011年 | 11篇 |
2010年 | 9篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 18篇 |
2005年 | 13篇 |
2004年 | 19篇 |
2003年 | 4篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有238条查询结果,搜索用时 125 毫秒
191.
192.
Erik J Olson Scott R R Haskell Rodney K Frank Howard D Lehmkuhl Lea Ann Hobbs Janet V Warg John G Landgraf Arno Wünschmann 《Journal of veterinary diagnostic investigation》2004,16(5):461-464
A dairy goat operation in Minnesota experienced a sudden, markedly increased mortality among its neonatal goats. Approximately 60 of 130 kids (46%) died. The animals had diarrhea and dyspnea of 1-2 days duration before death. Necropsy of 4 goat kids revealed marked, acute, catarrhal enteritis and fibrinous pleuropneumonia. Mannheimia haemolytica was isolated from the lungs. Basophilic inclusion bodies filling the entire nucleus were present in enterocytes of the ileum of 3 goats. Adenoviral particles were detected in the feces by electron microscopy and adenovirus was subsequently isolated from the intestinal content together with a parvo-like virus (dependovirus). Morphology, physicochemical characteristics, and neutralization tests indicated that the adenovirus resembled ovine adenovirus-2 (OAdV-2). However, the PstI restriction endonuclease pattern produced by the goat adenovirus was distinct from that of OAdV-2. This is the first report of enteritis in goats with an adenovirus antigenically related to OAdV-2 and with a parvo-like dependovirus. 相似文献
193.
Objective— (1) To determine the biomechanical stability of cervical spinal segment C5–C6 after ventral slot (VS) decompression and distraction–stabilization by a modified polymethylmethacrylate (PMMA) intervertebral plug technique (IVP) in an ovine model. (2) To determine if the distraction of the disk space is maintained after VS‐IVP, and the frequency of bony intervertebral union. Study Design— Experimental in vivo study in an ovine model with an in vitro control study. Animals— Adult (>2 years age), intact sheep (n=18). Methods— Ten sheep had VS/IVP surgery of C5–6 with computed tomography (CT) images obtained immediately before and after surgery, as well as 8 (n=10) and 24 (n=5) weeks postoperatively. Cervical spines harvested 8 weeks (8‐week group; n=5) and 24 weeks (24‐week group; n=5) after surgery had three‐dimensional (3D) flexibility tests in flexion–extension, axial rotation, and lateral bending. Image data was analyzed qualitatively and quantitatively in 3D. Eight ovine cervical spines served as controls and had biomechanical testing in intact condition (n=5) and after in vitro VS/IVP (n=5). Results— Significantly decreased range of motion (ROM) was noted in all loading modes when comparing in vitro operated spines and the 24‐week group to intact spines. The 8‐week group was not significantly different from the intact group, except in lateral bending. Quantitative CT analysis of treatment groups showed progressive disk space collapse and ventral implant migration. Intervertebral bony union did not occur. Conclusion— Biomechanical stability was obtained immediately after VS/IVP surgery, but ROM at 8 weeks was not different from intact spines. However, at 24 weeks, the operated level had regained stability similar to the immediate postoperative level. Distraction of the disk space was not maintained and bony union did not occur in this ovine model of VS/IVP. Clinical Relevance— In clinical situations requiring constant increased stability of cervical segments for an extended time, more rigid stabilization techniques are required. 相似文献
194.
195.
196.
197.
198.
Greta L. Heidner DVM Joe N. Kornegay DVM PhD Rodney L. Page DVM MS Richard K. Dodge MS Donald E. Thrall DVM PhD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1991,5(4):219-226
A retrospective study of 86 dogs with brain tumors was undertaken. Sixty-nine dogs had histologic confirmation of tumor type, whereas the remaining 17 dogs had CT evidence of a brain tumor. All dogs had neurologic abnormalities. Seven dogs received no treatment, 38 dogs received only symptomatic treatment, and 41 dogs received some form of definitive treatment, in addition to medical management. Types of definitive treatment included surgery, cobalt-60 radiation, whole-body hyperthermia, 125I implants, and chemotherapy, alone or in combination. The factor that was most associated with survival duration was mode of therapy. Those dogs who were treated with cobalt-60 radiation, with or without other combinations of therapy, lived significantly longer than dogs who received surgery (+/- 125I implants), or dogs who received symptomatic treatment (P = 0.01 and P less than 0.001, respectively). After statistic adjustment for treatment, multiplicity of brain involvement (solitary vs. multiple) provided prognostic information with respect to survival (P = 0.001), with dogs who had a solitary site of involvement having a better prognosis. After further adjustment, initial neurologic dysfunction (mild/moderate vs. severe) showed significance as prognostic variable (P = 0.005). Both the mild and moderate groups had a more favorable prognosis compared with dogs who had severe initial neurologic impairment. The median survival time for the 86 dogs was 1.0 month (range: 1 day-42.4 mo). Median survival times of dogs receiving: 1) no therapy or only symptomatic therapy, 2) surgery (+/- 125I), or 3) cobalt-60 radiation (+/- hyperthermia, +/- surgery) were 0.2, 0.9, and 4.9 months, respectively. 相似文献
199.
200.
Nuclear accidents that lead to melting of a reactor core create heterogeneous materials containing hundreds of radionuclides, many with short half-lives. The long-lived fission products and transuranium elements within damaged fuel remain a concern for millennia. Currently, accurate fundamental models for the prediction of release rates of radionuclides from fuel, especially in contact with water, after an accident remain limited. Relatively little is known about fuel corrosion and radionuclide release under the extreme chemical, radiation, and thermal conditions during and subsequent to a nuclear accident. We review the current understanding of nuclear fuel interactions with the environment, including studies over the relatively narrow range of geochemical, hydrological, and radiation environments relevant to geological repository performance, and discuss priorities for research needed to develop future predictive models. 相似文献