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   2468篇
  免费   231篇
林业   6篇
农学   4篇
  8篇
综合类   30篇
农作物   3篇
水产渔业   4篇
畜牧兽医   2636篇
植物保护   8篇
  2023年   52篇
  2020年   95篇
  2019年   3篇
  2018年   59篇
  2017年   67篇
  2016年   40篇
  2015年   68篇
  2014年   104篇
  2013年   109篇
  2012年   66篇
  2011年   82篇
  2010年   76篇
  2009年   85篇
  2008年   68篇
  2007年   50篇
  2006年   34篇
  2005年   31篇
  2004年   57篇
  2003年   61篇
  2002年   68篇
  2001年   63篇
  2000年   58篇
  1999年   68篇
  1998年   102篇
  1997年   101篇
  1996年   80篇
  1995年   79篇
  1994年   71篇
  1993年   89篇
  1992年   104篇
  1991年   80篇
  1990年   91篇
  1989年   79篇
  1988年   70篇
  1987年   77篇
  1986年   36篇
  1985年   49篇
  1984年   37篇
  1983年   52篇
  1982年   19篇
  1981年   2篇
  1980年   3篇
  1972年   1篇
  1969年   1篇
  1968年   2篇
  1966年   1篇
  1960年   1篇
  1933年   1篇
  1917年   1篇
  1910年   1篇
排序方式: 共有2699条查询结果,搜索用时 15 毫秒
131.
Objective — This study evaluates the association between dental procedures and bacteremia in dogs, including a comparison of bacteria isolated from plaque and blood, severity of the bacteremia versus the severity of dental disease, and the longevity of bacteremia.
Study Design — Bacteria cultured from the blood over time were compared with those isolated from the plaque and crevicular fluid and in relation to severity of dental disease.
Animals or Sample Population — Twenty adult greyhounds.
Methods — Blood samples were collected for culture before induction of general anesthesia, immediately after intubation, 20 minutes after initiation of the dental procedure, and at 10-minute intervals until 10 minutes after the dental procedure was completed. Samples of plaque were taken for microbiological culture.
Results — Sixty to ninety percent of the bacterial genera isolated from the plaque were present in the blood. Dogs classified according to severity of dental disease showed no difference in the total number of different species or number of different Gram-negative, Gram-positive, or anaerobic bacteria isolated from plaque or blood (P <.05). Bacteremia was present in all of the dogs studied, within 40 minutes from the initiation of the dental procedure, regardless of the severity of oral disease.
Conclusions — Gram-negative, Gram-positive, and anaerobic bacteria are present in blood during dental procedures; the bacteremia can persist beyond the dental procedure, and is not associated with the severity of dental disease.
Clinical Relevance — The nature and extent of bacteremia occuring during routine dental procedures is important in understanding a potential risk to dogs.  相似文献   
132.
Correlation Between Serum Creatine Kinase Activities And Anorexia in Cats   总被引:1,自引:1,他引:0  
There are no available biochemical analyses that will reliably identify malnourished cats or enable monitoring them during supportive alimentation. Studies in people indicate that creatine kinase (CK) activity is high in malnourished patients and may decrease in response to nutritional intervention. The purpose of this study was to determine the value of quantifying serum CK activities in anorectic cats and to assess the usefulness of this test in monitoring nutritional support in these patients. Serum CK activity was evaluated in nonanorectic cats (Group 1, n = 25), and in hospitalized, anorectic cats that received nutritional support through a nasoesophageal tube (Group 2, n = 25). Anorectic cats had a significantly higher serum CK activity (median = 2,529 U/L, range 88 to 153,000 U/L) than the control group (median = 175 U/L, range 81 to 363 U/L, P < .001). There were significant positive correlations between serum CK and both aspartate transaminase (AST) ( P < .05; r = .59) and lactate dehydrogenase (LDH) (P < .05; r = .41) activities. Serum CK activity was significantly lower in anorectic cats after 48 hours of nutritional support than at time 0 ( P < .001) and eventually returned to normal with continued support. Serum CK activity may serve as a useful marker in assessing and monitoring nutritional status in cats.  相似文献   
133.
Comparison was made of the holding power of 5.5 and 4.5 mm cortical orthopedic screws inserted into third metacarpal and metatarsal cadaver bones from 3- and 8-year-old horses. The tensile strength of these screws was tested mechanically. In nine comparative trials of these screws, 5.5 mm screws pulled out of bone in five trials at an average of 116.0 kg tensile force and broke in four trials at an average of 1383.2 kg. A 4.5 mm screw pulled out of bone at 834.5 kg in one trial, and screws broke at an average of 849.2 kg in eight trials. The larger 5.5 mm screw required a significantly greater (p = 0.022) pullout force than the mean force at 4.5 mm screw breakage. Fixation failure was due to screw breakage or bone shear, with 5.5 mm screws occasionally creating bone fragmentation during pullout. The average tensile breaking strengths of the 5.5 mm screws (1391.4 kg) and 4.5 mm screws (832.7 kg) determined mechanically were similar to forces at screw breakage during pullout testing in bone. Since the 5.5 mm screws have greater holding power and tensile strength than 4.5 mm screws, the use of the 5.5 mm screw in fracture repair in adult horses is recommended.  相似文献   
134.
135.
136.
A technique using a third bar and guide clamp was developed to permit reduction and stabilization of distal limb fractures with full pins and two connecting bars, one on each side of the bone. The system uses only single Kirschner clamps. Four distal limb fractures were stabilized using this technique. Closed reduction was used in three dogs to avoid devitalization of fragments and avoid contamination of a closed fracture. The fracture site stability achieved with this configuration allowed early return to weight bearing and rapid bone healing.  相似文献   
137.
Through the use of a purebred dog skull collection, specific positioning recommendations were established for radiography for the three skull types. It is suggested that the central ray of the beam be maintained at the following mean angles relative to the hard palate for the rostrodorsal-to-caudoventral oblique projection of the foramen magnum: dolicocephalic, 30° mesaticephalic, 20° and brachycephalic, 10°. It is recommended that the head be axially rotated as follows to radiographically separate the roots of the superior canine teeth: dolicocephalic, 48° mesaticephalic, 43° and brachycephalic, 35°. If only the cheek teeth require evaluation, the head should be rotated as follows: dolicocephalic, 37° mesaticephalic, 34° and brachycephalic, 25°. For evaluation of the inferior cheek teeth, it is recommended that the head be rotated as follows: dolicocephalic, 46° mesaticephalic, 44° and brachycephalic, 28°. It is recommended that radiographs of the temporo-mandibular joint be made with the skull axially rotated 10° and longitudinally obliqued as follows: dolicocephalic, 10° mesaticephalic, 14° and brachycephalic, 27°. Suggestions for open-mouth projections for evaluation of the tympanic bullae are that the central ray maintain the following angles relative to the hard palate: dolicocephalic, 4° mesaticephalic, 9° and brachycephalic, 21°. It is recommended that a caudoventral-rostrodorsal oblique projection of the nasal cavity made at 30° to the hard palate replace the open-mouth ventrodorsal in brachycephalic breeds.  相似文献   
138.
Gastric emptying time and small intestinal transit time in dogs are frequently discussed. However, it is often of interest to the radiologist to know what normal small intestinal emptying times should be. A total of 15 upper gastrointestinal studies was performed on five internal parasite-free, normal, standard Beagle dogs with three studies on each dog, 6 days apart. The ages and weights of the dogs ranged from 2–8 years and from 12.4–13.7 kg, respectively. Following 24-hour fasting, a dose of 10 ml/kg bw of 60% wt/vol barium sulfate suspension was administered through a stomach tube. Then, sequential radiographs were made at 30-minute intervals until the entire contrast medium column was in the colon and cecum. The mean, standard deviation, and range of gastric emptying time, small intestinal transit time, and small intestinal emptying time were 76 ± 16.7 (30–120), 73 ± 16.4 (30–120), and 214 ± 25.1 (180–300) minutes, respectively. This study offers the possibility that small intestinal emptying time may be used to further evaluate patients with suspected small intestinal partial obstruction, pseudo-obstruction, ischemia, or lymphangiectasia.  相似文献   
139.
Osteochondrosis of the lateral femoral condyles was diagnosed radiographically in an 8-month-old, female Arabian horse, which had been presented with a hindlimb lameness. The diagnosis was confirmed by gross and microscopic pathology. The location of the lesions was considered unusual for osteochondrosis in the horse.  相似文献   
140.
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