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   157篇
  免费   17篇
  国内免费   1篇
农学   1篇
基础科学   1篇
  4篇
综合类   19篇
农作物   3篇
水产渔业   4篇
畜牧兽医   137篇
植物保护   6篇
  2023年   1篇
  2021年   3篇
  2020年   3篇
  2019年   3篇
  2018年   6篇
  2017年   4篇
  2016年   8篇
  2015年   5篇
  2014年   7篇
  2013年   13篇
  2012年   1篇
  2011年   4篇
  2010年   3篇
  2009年   15篇
  2008年   4篇
  2007年   5篇
  2006年   6篇
  2005年   3篇
  2004年   5篇
  2003年   3篇
  2002年   1篇
  1999年   5篇
  1998年   8篇
  1997年   9篇
  1996年   4篇
  1995年   4篇
  1994年   1篇
  1993年   5篇
  1992年   2篇
  1991年   6篇
  1990年   7篇
  1989年   4篇
  1988年   4篇
  1987年   1篇
  1979年   2篇
  1975年   1篇
  1974年   2篇
  1972年   3篇
  1971年   1篇
  1966年   1篇
  1947年   1篇
  1943年   1篇
排序方式: 共有175条查询结果,搜索用时 93 毫秒
61.
Summary The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 ± 6.9 min with TK and 82.8 ± 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.  相似文献   
62.
63.
Objective To determine the usefulness of a snake venom detection kit (SVDK) in the management of envenomed cats.
Design A clinical study.  

Animals


Twenty-two cats were investigated.
Procedure Cats injected subcutaneously with approximately 0.25 or 1.0 lethal dose (LD) of tiger snake venom or 1 or 4 LD of brown snake venom were observed for clinical symptoms of envenomation at intervals over the ensuring 24 to 48 hours(h). Blood and urine samples were taken at regular intervals and assayed in a quantitative laboratory assay for snake venoms. Selected samples were assayed in parallel in a rapid, semi-quantitative SVDK.
Results The studies showed that it was important to estimate the elapsed time from envenomation to presentation. If this time was less than 8 h, blood was the most appropriate sample and a negative result should exclude serious envenomation. If the elapsed time exceeded 8 h, it was essential that urine be sampled. Venom levels in urine were high at 8 h and approached the level of test sensitivity over 24 to 48 h; however by this time clinical signs were obvious in endangered cats.  

Conclusions


Careful use of the SVDK is a valuable aid in the management of a potentially envenomed cat.  相似文献   
64.
65.
66.
Tulathromycin, a long acting macrolide antibiotic, has demonstrated efficacy against respiratory pathogens including Mycoplasma bovis and M. hyopneumoniae. A pharmacokinetic study was performed to evaluate the clinical applicability of tulathromycin in desert tortoises following a single intramuscular dose of 5 mg/kg. A single blood sample was collected from 110 different desert tortoises at 0.25, 0.5, 1, 4, 8, 24, 48, 72, 120, and 240 h following drug administration. Plasma concentrations of the parent form of tulathromycin were measured using liquid chromatography/mass spectrometry. As each tortoise was only bled once, pharmacokinetic parameters were initially estimated using a naïve pooled data approach. Given the variability in the data, population‐based compartmental modeling was also performed. Using nonparametric population compartmental modeling, a two‐compartment model with first‐order absorption and elimination best fit the data. An observed Cmax of 36.2 ± 29.7 μg/mL was detected at 0.25 h (observed Tmax). The elimination half‐life (T½el) was long (77.1 h) resulting in detectable plasma concentrations 240 h postadministration. This study represents a preliminary step in evaluating the utility of tulathromycin in chelonian species and demonstrates that population data modeling offers advantages for estimating pharmacokinetic parameters where sparse data sampling occurs and there is substantial variability in the data.  相似文献   
67.
We assessed the effects of different feeding regimes on reproductive traits in coho salmon, Oncorhynchus kisutch. Ration treatments subjected fish to different energy levels during oocyte proliferation (Year 1) and oocyte maturation (Year 2). Fish from 10 full‐sibling families were fed at either the recommended feeding rate or double the recommended ration during the first year. At the beginning of the second year, each ration group was split again into recommended and double ration tanks for a total of four dietary treatments. At the end of the second year, 365 females from the four treatment groups were spawned and body weight, egg weight, and egg number were measured. Overall, the fish fed the double ration during both years grew the fastest (50.1% larger than controls), had the highest egg number (46.3% larger), and had the largest eggs (9.6% larger), although similar increases were observed feeding at the double ration level during the second year alone. Ration modification produced significant changes in some reproductive traits, especially egg number, while family effects had a greater influence on relative fecundity (eggs/g female body weight) and egg weight. In fact, family effects were significant for all of the traits. Results indicate that reproductive traits can be manipulated through changes in ration and/or via genetic selection, either directly or indirectly.  相似文献   
68.
The aim of this study was to determine the association between the oestrous response of pre‐pubertal gilts to gonadotrophin injection or boar exposure and their subsequent farrowing rate and litter size. At 154 days of age, randomly selected pre‐pubertal gilts received an intramuscular injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600®; Merck Animal Health; n = 181). From the remaining pool of animals not treated with hormones, the first gilts showing signs of oestrus were selected to act as controls (n = 201). Boar exposure began at 155 days of age for both groups, and gilts were bred at a weight of approximately 130 kg. Comparisons were made between PG600®‐treated gilts exhibiting oestrus or not within 7 days post‐injection (early and late responders, respectively) and control gilts exhibiting oestrus or not within 30 days after beginning of boar exposure (select and non‐select control gilts, respectively). By 162 days, oestrus was detected in 67.5% of PG600®‐treated gilts compared with 5.7% of control gilts (p < 0.0001). The proportion of animals observed in oestrus at least three times before breeding was greater for select control gilts compared with early and late responder PG600®‐treated gilts (p  0.001). There were no significant differences in farrowing rate and litter size between the four treatment groups. These data indicate that PG600® is an effective tool to induce an earlier oestrus in gilts, that subsequent farrowing rate and born alive litter size compare favourably to that of select gilts and that gilts failing to respond promptly to hormonal stimulation do not exhibit compromised fertility.  相似文献   
69.
To meet weekly breeding targets, it is occasionally necessary to inject exogenous gonadotrophins to induce oestrus in prepubertal gilts. However, the gilt oestrus response to equine chorionic gonadotrophin (eCG) either alone or in combination with human chorionic gonadotrophin (hCG) can be unpredictable. The objective of the present study was to examine possible reasons for this unpredictability. Prepubertal gilts (90 kg and 153 days of age, n = 109) received an injection of either 600 IU eCG or a combination of 400 IU eCG and 200 IU hCG (PG600), or were non-injected controls, and were then exposed to a mature boar for 15 min daily for 7 days for oestrus detection. At the time of injection, real-time ultrasound revealed that the gilt ovaries had primarily 1–2 mm follicles. Blood samples were obtained at time of hormone injection (day 0) and at days 3, 7 and 10 for assay of serum progesterone concentrations. The oestrus responses by 7 days were15.5%, 73.3% and 0%, for eCG, PG600, and control gilts, respectively (p < 0.001). The oestrus response improved (p < 0.05) with increasing body weight. Based on circulating progesterone levels, all oestrous gilts ovulated except for four of the PG600 gilts. Failure to express oestrus in PG600 gilts was not associated with a premature rise in progesterone.  相似文献   
70.
The follicle and hormone aspects of diameter deviation and development of one dominant (≥28 mm) follicle (1DF) vs two dominant follicles (2DF) were studied in 32 ovulatory follicular waves in mares. Follicles were ranked each day as F1 (largest) to F3. The beginning of deviation was designated day 0 and preceded the first increase in the differences in diameter between F1 and F2 in the 1DF group and between a combination of F1 and F2 vs F3 in the 2DF group. One dominant follicle and 2DF developed in 21 (66%) and 11 (34%) waves, respectively. Double ovulations occurred in only one of the waves with 2DF. In 8/11 waves with 2DF, a second deviation occurred between F1 and F2 on 2.5 ± 0.4 days after the first deviation. On day 0, 1DF and 2DF waves were similar in number of days after ovulation, number of follicles, difference in diameter between F1 and F2, and plasma concentrations of LH, estradiol and immunoreactive inhibin. The interval from maximum FSH concentration to day 0 was longer (p < 0.05) and FSH concentration was lower (p < 0.05) on days -1 to 4 in the 2DF group. The similarities on day 0 in the characteristics of 1DF and 2DF waves despite the differences in the declining portions of the FSH profile indicated that a specific day of the FSH decline or a specific concentration were not factors in initiating deviation. Unlike reported results in heifers, the results in mares did not indicate a hormonal basis for the development of 2DF or two deviations.  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