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   101篇
  免费   2篇
林业   21篇
  6篇
综合类   13篇
水产渔业   6篇
畜牧兽医   52篇
植物保护   5篇
  2020年   1篇
  2018年   2篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2013年   16篇
  2011年   2篇
  2010年   2篇
  2009年   5篇
  2008年   2篇
  2007年   1篇
  2006年   2篇
  2005年   5篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  1999年   5篇
  1998年   7篇
  1997年   2篇
  1996年   6篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1991年   3篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1986年   2篇
  1984年   4篇
  1983年   3篇
  1982年   3篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1970年   1篇
排序方式: 共有103条查询结果,搜索用时 281 毫秒
91.
A Late Cretaceous (92 to 86 million years ago) vertebrate assemblage from the high Canadian Arctic (Axel Heiberg Island) implies that polar climates were warm (mean annual temperature exceeding 14 degreesC) rather than near freezing. The assemblage includes large (2.4 meters long) champsosaurs, which are extinct crocodilelike reptiles. Magmatism at six large igneous provinces at this time suggests that volcanic carbon dioxide emissions helped cause the global warmth.  相似文献   
92.
93.
When Bill Manktelow died at his home in his 74th year on the 3rd of May, the veterinary profession lost a major figure whose work over 50 years has influenced many people in all branches of the profession.  相似文献   
94.
Abstract

Extract

A single case of the inherited lysosomal storage disease known as mucopolysaccharidosis-IIIA (MPS-IIIA), due to a deficiency of the enzyme heparan sulphatase, was reported in an 18-month-old male Huntaway dog (Jolly et al 2000 Jolly, RD, Allan, FJ, Collett, MG, Rozaklis, T, Muller, VJ and Hopwood, JJ. 2000. Mucopolysaccharidosis IIIA (Sanfilippo syndrome) in a New Zealand Huntaway dog with ataxia. New Zealand Veterinary Journal, 48: 144148. [Taylor &; Francis Online], [Web of Science ®] [Google Scholar]). He had developed normally but when presented with a history of progressive ataxia over the preceding month, had a high stepping, prancing gait and difficulty in jumping into a utility vehicle. In addition, he had started to defaecate in his kennel. Following diagnosis of the enzyme deficiency, the mutant heparan sulphatase gene was sequenced and a PCR/restriction enzyme diagnostic test developed, based on the mutation. This is capable of detecting both homozygous and heterozygous individuals (Yogalingam et al 2000 Yogalingam, G, Pollard, T, Gliddon, B, Jolly, RD and Hopwood, JJ. 2001. Identification of a mutation causing mucopolysaccharidosis type IIIA in New Zealand Huntaway dogs. Genomics, 79: 150153.  [Google Scholar]).  相似文献   
95.
Extract

A lethal congenital polycystic kidney disease (PCKD) has been known in lambs in New Zealand for more than 50 years and assumed to be genetic in origin. We have studied this in lambs from an experimental mating in a flock experiencing an outbreak the previous year. Two Perendale rams identified by DNA profiling (SignaGen) as sires of PCKD lambs were each mated to the other's daughters. From 71 such matings, 10 ewes gave birth to 15 PCKD lambs of both sexes. The results are in accord with those expected for a recessive autosomal trait. All lambs were dead or died shortly after birth. Their abdomens were distended by enlarged kidneys 40–140 mm in length. Their cut surface showed a multitude of cystic spaces 1–5 mm in diameter in both the cortex and medulla. Livers of affected lambs showed complex tubular and cystic patterns of bile ducts containing bile, and supported by an excess of fibrous tissue. Cystic changes also occurred in the pancreas and salivary glands.  相似文献   
96.
97.
Bovine venereal campylobacteriosis (BVC) is a major cause of economic loss to the cattle industries in different parts of the world. Camplylobacter fetus subsp. venerealis (Cfv), the main causative agent of BVC, is highly adapted to the genital tract of cattle and is transmitted by carrier bulls. However, infertility and abortions can also be caused by the intestinal pathogens C. fetus subsp. fetus (Cff), and C. jenuni, which are not venereally transmitted. Bovine venereal campylobacteriosis, caused by Cfv associated with lowered fertility, embryo mortality and abortion, repeated returns to service, reduced pregnancy rates and extended calving intervals, has the highest prevalence in developing countries where natural breeding in cattle is widely practised. The epidemiology, pathogenesis and diagnosis of the disease have been the subject of previous reviews. The main focus of this review is to highlight the epidemiology of this disease with particular reference to geographical distribution and recent advances in molecular diagnostic techniques. It is hoped that further research interest of scientists will be stimulated with a view to finding lasting solutions to the reproductive problems associated with the disease for better livestock productivity, particularly in developing endemic countries.  相似文献   
98.
In 1998, Countdown Downunder, Australia's national mastitis and cell count control programme, was created. With funding from the country's leading dairy organisation, Dairy Australia, this programme was originally intended to run for three years but is now in its tenth year. As it was the first time Australia had attempted a national approach to mastitis control on the farm, the first three years of the programme were largely concerned with the development of resources to be used by farmers and service providers. The second three years were devoted to training with both groups. Since that time, Countdown Downunder has entered into a second resource development phase. The goal of the programme was to achieve a reduction in the bulk milk somatic cell count from the Australian dairy herd. To achieve this, the programme had to develop resources with clear and consistent messages around mastitis and somatic cell count control on farms. It was determined that progress toward the goals would be made more rapidly if service providers were trained in the use of these resources prior to farmers. This paper reviews the Countdown Downunder programme from 1998 to 2007.  相似文献   
99.
"Dip-Pen" nanolithography   总被引:1,自引:0,他引:1  
A direct-write "dip-pen" nanolithography (DPN) has been developed to deliver collections of molecules in a positive printing mode. An atomic force microscope (AFM) tip is used to write alkanethiols with 30-nanometer linewidth resolution on a gold thin film in a manner analogous to that of a dip pen. Molecules are delivered from the AFM tip to a solid substrate of interest via capillary transport, making DPN a potentially useful tool for creating and functionalizing nanoscale devices.  相似文献   
100.
The pre‐medicant chosen may influence the ease with which gastroduodenoscopy (GD) is performed. The purpose of this study was to evaluate the relative ease of GD in cats under ketamine and isoflurane anesthesia after IM injection of hydromorphone (H, 0.1 mg kg?1), hydromorphone plus glycopyrrolate (HG, 0.1 mg kg?1 (H), 0.01 mg kg?1 (G)), medetomidine (M, 0.03 mg kg?1), or butorphanol (B, 0.4 mg kg?1). Eight cats were assigned randomly to receive each treatment in a cross‐over design with at least 7 days between treatments. Twenty minutes after pre‐medication, medetomidine produced greater (p = 0.001) sedation than the other treatments when assessed, using a subjective ordinal scale. The cats were injected with ketamine (10 mg kg?1 IM), orotracheally intubated, connected to a pediatric circle breathing system, and allowed to spontaneously breathe isoflurane in oxygen. Once end‐tidal isoflurane concentration was stable at 1.4% for 15 minutes, endoscopy was started. A single endoscopist (REG), who was unaware of the treatment used, performed all endoscopies. The endoscopist scored the difficulty of endoscopy subjectively (0–3). The significance of differences between treatments was evaluated using Friedman's test. Time for entering the stomach was 9.4 (4.7–15.9) (median (minimum–maximum)), 6.6 (5.2–11.7), 8.4 (6.3–16.5), and 7.7 (5.1–14.7) seconds and for entering the duodenum from the stomach was 20.5 (13.8–40.9), 18.2 (10.3–39.8), 20.2 (16.2–119.5), and 22.2 (11.8–83.8) seconds for H, HG, M, and B treatments, respectively. There were no significant differences in the time for, or difficulty of, endoscopy. We conclude that any of these drugs can be used satisfactorily at the doses and combinations tested to pre‐medicate cats prior to general anesthesia for GD.  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