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   596篇
  免费   70篇
林业   35篇
农学   15篇
基础科学   1篇
  55篇
综合类   85篇
农作物   10篇
水产渔业   33篇
畜牧兽医   392篇
园艺   7篇
植物保护   33篇
  2024年   3篇
  2023年   5篇
  2022年   6篇
  2021年   9篇
  2020年   13篇
  2019年   25篇
  2018年   18篇
  2017年   21篇
  2016年   13篇
  2015年   10篇
  2014年   23篇
  2013年   31篇
  2012年   48篇
  2011年   53篇
  2010年   23篇
  2009年   18篇
  2008年   41篇
  2007年   43篇
  2006年   36篇
  2005年   31篇
  2004年   28篇
  2003年   28篇
  2002年   32篇
  1995年   4篇
  1994年   4篇
  1993年   3篇
  1989年   4篇
  1988年   4篇
  1987年   4篇
  1985年   6篇
  1984年   2篇
  1983年   4篇
  1982年   3篇
  1981年   2篇
  1980年   3篇
  1978年   4篇
  1977年   3篇
  1975年   2篇
  1974年   3篇
  1971年   2篇
  1970年   3篇
  1969年   4篇
  1968年   2篇
  1967年   2篇
  1966年   3篇
  1965年   2篇
  1964年   2篇
  1962年   2篇
  1958年   2篇
  1942年   2篇
排序方式: 共有666条查询结果,搜索用时 530 毫秒
81.
82.
83.
Severe hydroureter and hydronephrosis secondary to ureteral obstruction by calculus were present in a guinea pig. A palliative ultrasound-guided percutaneous antegrade hydropropulsion was performed under general anesthesia to relieve the ureteral obstruction and the associated clinical signs. We describe the technique and the considerations for its potential application in similar cases.  相似文献   
84.
CASE HISTORY: A mature male tuatara was presented with a history of recurrent cloacal prolapse.

CLINICAL AND PATHOLOGICAL FINDINGS: The prolapsed tissue included a 12 mm diameter mass, which histologically showed cords and nodules of neoplastic epithelial cells.

DIAGNOSIS: The mass was diagnosed as a squamous cell carcinoma with ulceration of the overlying stratified squamous epithelium and diffuse inflammation of the surrounding dermis.

CLINICAL RELEVANCE: This case presented a rare opportunity to investigate squamous cell carcinoma in a long-lived lower vertebrate species. Future recurrence or metastasis of the mass may add useful information to the current base of knowledge of the behaviour of malignant neoplasms in reptiles.  相似文献   
85.
Abstract

CASE HISTORY: A 13-year-old Thoroughbred mare was presented with a history of mild colic over 3 days. This colic had acutely exacerbated and was unresponsive to analgesic treatment, and was referred to Massey University Veterinary Teaching Hospital.

CLINICAL FINDINGS: On examination the heart rate was 100 beats per minute, and mucous membranes were pale and tacky. A large mass was detected on transrectal palpation in the caudal abdomen to the left of midline. Explorative laparotomy revealed severe haemoperitoneum and several masses that were associated with the reproductive tract. The mare was then subject to euthanasia. On post-mortem examination, adjacent and attached to each ovary were soft, lobulated dark red masses up to 200 mm in diameter. Similar masses were present in the omentum and on the peritoneal surface of the diaphragm and the serosa of the spleen and liver. Histopathology revealed that the neoplastic component of the masses comprised proliferating cuboidal to columnar cells forming disorganised acini and cords separated by dense collagenous stroma. Immunohistochemistry showed the neoplastic cells were positive for cytokeratin AE1/AE3 and vimentin, but negative for cytokeratin 7 and inhibin α.

DIAGNOSIS: Bilateral ovarian adenocarcinoma with transcoelomic metastasis and terminal decompensation due to rupture of a neoplastic mass and consequent haemoperitoneum.

CLINICAL RELEVANCE: To the authors' knowledge, bilateral ovarian adenocarcinoma has not been previously reported in a horse. Ovarian adenocarcinoma should be considered when horses present with haemoperitoneum and colic. Further research is required on the immunohistochemical differentiation of adenocarcinoma of ovarian and intestinal origin in the horse.  相似文献   
86.
87.
Mycobacterium avium subspecies paratuberculosis (MAP) disseminated infection in dairy cattle affects animal health and productivity and is also a potential public health concern. The study objectives were to characterize MAP disseminated infection in dairy cattle and to determine the role of antemortem tests in detecting cattle with disseminated infection. Forty culled dairy cows representing a variety of serum enzyme-linked immunosorbent assay (ELISA) results and body conditions were selected for the study. The physical condition of the cows was assessed via clinical examination prior to euthanasia and blood and feces were collected and tested by serum ELISA and fecal culture, respectively. Fifteen tissues were aseptically collected from each cow during necropsy and cultured for isolation of MAP. Disseminated infection was diagnosed when MAP was isolated in tissues other than the intestines or their associated lymph nodes (LNs) and was distinguished from infection found only in the gastrointestinal tissues and from absence of infection. Of the 40 cows in the study, 21 had MAP disseminated infection. Results showed that 57% (12/21) of cows with disseminated infection had average to heavy body condition and no diarrhea. Cows with disseminated infection had no to minimal gross pathologic evidence of infection in 37% (8/21) of cases. Only 76% (16/21) of cows with disseminated infection had positive historical ELISA results and only 62% (13/21) had a positive ELISA at slaughter. Thus, antemortem evidence of MAP infection was lacking in a high proportion of cows where MAP disseminated infection was confirmed.  相似文献   
88.
89.
For a suture that spans a joint to provide support without limiting range of motion, its attachment points on either side of the joint must remain the same distance from each other from full extension to full flexion. The effect of location of the tibial crest attachment for a fabello-tibial crest suture was studied in seven canine cadaveric stifles. The distance from a fabella marker to each of 11 tibial markers was determined from radiographs of each limb, as it progressed from 150 degrees to 130 degrees , 105 degrees , 90 degrees , 65 degrees and 45 degrees of flexion. The marker locations that were more proximal and cranial on the tibial crest had the least percent change in distance. The effect of anchoring the suture to the femur at a site other than the fabella was investigated using the same radiographs. Five marks were placed in a grid on the caudal portion of the femoral condyle and supracondylar region. The mean percent change in length from each femoral point to the five more proximal and cranial tibial markers was determined. The least change in length occurred for those femoral points located close to the origin of the cranial cruciate ligament. Locations more proximal or cranial resulted in large changes in length, particularly when matched with less ideal tibial locations. Although this study does not directly examine length changes in sutures, it demonstrates that there are some locations for the origin and insertion of an extracapsular suture that are associated with less length change than others, and also forms the basis for future investigations.  相似文献   
90.
Objective— To report surgical planning, technique, and long-term outcome of custom transcutaneous tibial implants used to restore ambulation after bilateral pelvic limb amputation in a dog.
Study Design— Case report.
Animals— A 4-year-old, 25.5 kg, female spayed, Siberian Husky.
Methods— Computed tomographic scans of the pelvic limbs were used to build sterolithographic models of the remaining tibia after bilateral amputation of the distal aspect of the tibiae. The sterolithographic models facilitated fabrication of implants that would replace the missing distal segments of the tibiae. Custom implants were surgically placed in both limbs.
Results— Assisted ambulation was restored immediately postoperatively and unassisted locomotion occurred at 7 days. At 14 months, aseptic loosening of the right implant occurred, it was removed and a 2nd transcutaneous implant was fabricated and implanted. At 26 months after initial surgery and 17 months after revision of the right implant, function is restored at a walk, trot, and run.
Conclusion— Based on over a 2-year follow-up, transcutaneous tibial implants allowed for restoration of locomotion.
Clinical Relevance— Transcutaneous tibial implants offer a potentially viable treatment option for restoring ambulation after amputation of the distal aspect of the tibiae in the dog.  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