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   65篇
  免费   2篇
  国内免费   1篇
林业   1篇
  1篇
综合类   24篇
水产渔业   4篇
畜牧兽医   37篇
植物保护   1篇
  2022年   1篇
  2021年   1篇
  2018年   2篇
  2016年   2篇
  2013年   2篇
  2011年   1篇
  2009年   3篇
  2008年   3篇
  2007年   1篇
  2006年   1篇
  2005年   3篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1998年   3篇
  1997年   1篇
  1996年   6篇
  1995年   3篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   5篇
  1985年   1篇
  1984年   2篇
  1979年   1篇
  1977年   1篇
  1971年   1篇
  1947年   1篇
  1944年   1篇
排序方式: 共有68条查询结果,搜索用时 15 毫秒
11.
Response     
  相似文献   
12.
Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.  相似文献   
13.
14.
The concentrations of several post mortem aqueous humour chemical constituents were compared with ante mortem serum chemical values in the horse. Urea nitrogen and creatinine values in post mortem aqueous humour were good predictors of ante mortem serum values. Aqueous humour urea nitrogen increased only slightly and creatinine did not change significantly for up to 24 h after death. Formulae were derived for calculating estimated ante mortem serum urea nitrogen and creatinine from aqueous humour values obtained after death. These results from normal horses identify analytes that are accurate predictors of ante mortem serum values. Determination of post mortem aqueous humour urea nitrogen of creatinine may assist in interpretation of the functional significance of equivocal histological lesions in the kidney.  相似文献   
15.
16.
Fossils discovered in Lower Cretaceous (Aptian) rocks in the Tenere Desert of central Niger provide new information about spinosaurids, a peculiar group of piscivorous theropod dinosaurs. The remains, which represent a new genus and species, reveal the extreme elongation and transverse compression of the spinosaurid snout. The postcranial bones include blade-shaped vertebral spines that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous.  相似文献   
17.
Changes in the plasma and liver concentrations of alpha-tocopherol in sheep kept in an animal house, grazed on pasture, grazed on pasture and fed an oat/lupin grain supplement, or grazed on toxic lupin stubble were monitored following no, oral or intramuscular administration of alpha-tocopherol. It was concluded that intramuscular administration was most effective because it caused longer periods of elevated plasma alpha-tocopherol concentrations in most situations investigated and consistently higher concentrations of alpha-tocopherol in the liver, compared to oral administration. The dose rates of alpha-tocopherol given, the vehicle for alpha-tocopherol in the injectable preparation, the different diets consumed and the concurrent occurrence of lupinosis all influenced the results. In spite of this a significant positive correlation existed between the terminal liver and plasma alpha-tocopherol concentrations.  相似文献   
18.
Four hundred and four dogs from 9 pounds in Sydney were examined for circulating microfilariae and antigens of Dirofilaria immitis. One hundred of these were also examined post mortem for adult heartworms. The prevalence of infection in the 404 dogs as shown by serology was 11.4%, and 5.9% had circulating microfilariae of D immitis. Adult heartworms were present in 15 of 100 dogs. Dipetalonema reconditum microfilariae were present in 3.7% of dogs. Dirofilariosis is still a common and important parasite of dogs in the Sydney region and chemoprophylaxis is recommended.  相似文献   
19.
20.
The aim of the study was to identify beta‐haemolytic streptococci in the vagina of bitches who had delivered healthy litters and bitches who had delivered litters in which neonatal deaths occurred. Fifty‐one bitches divided into two groups were used. Group 1 (G1) included 28 bitches that had delivered healthy litters and group 2 (G2) included 23 bitches that had delivered puppies who died in the neonatal period. Two vaginal samples were taken, one in proestrus and the other at the end of gestation (EG). Beta‐haemolytic Streptococcus (BS) was isolated from 16 bitches (57%) in G1 and from 21 bitches (91%) in G2. The bacteriological cultures, serological tests (Streptex®) and PCR assay allowed identification of Streptococcus canis and Streptococcus dysgalactiae in G1 and G2. Ultramicroscopic studies allowed the observation of M Protein and capsules in strains of S. dysgalactiae and S. canis in G1 and G2. The S. canis strains isolated from G2 showed thicker capsules than S. canis strains isolated from G1 (234 ± 24.2 vs 151.23 ± 28.93 nm; p < .001.). No differences were observed in capsule thickness between strains of S. dysgalactiae isolated from G1 and G2 (210 ± 13.54 vs 211.66 ± 19.67 nm; p > .70). All strains of beta‐haemolytic Streptococcus isolated were penicillin sensitive. Penicillin was administered from EG to 5 days post‐partum in 10 G2 females with isolation of BS (G2A). Saline solution was administered in eleven G2 females with isolation of BS (G2B). Ninety per cent of the puppies survived in G2A and 25% survived in G2B. Our results suggest BS is involved in canine neonatal deaths.  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