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   63篇
  免费   7篇
综合类   7篇
畜牧兽医   60篇
园艺   2篇
植物保护   1篇
  2023年   1篇
  2020年   4篇
  2019年   1篇
  2017年   1篇
  2016年   6篇
  2015年   1篇
  2014年   1篇
  2013年   6篇
  2012年   1篇
  2011年   1篇
  2010年   4篇
  2009年   2篇
  2008年   2篇
  2007年   1篇
  2006年   1篇
  2005年   3篇
  2004年   1篇
  2001年   3篇
  1999年   2篇
  1998年   1篇
  1997年   7篇
  1996年   7篇
  1995年   2篇
  1994年   2篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
排序方式: 共有70条查询结果,搜索用时 31 毫秒
21.
22.
It is well established that reproductive function is metabolically gated. However, the mechanisms whereby energy stores and metabolic cues influence appetite, energy homeostasis and fertility are yet to be completely understood. Adipose tissue is no longer considered as only a depot to store excess energy. Recent findings have identified numerous genes, several neurotrophic factors, interleukins, insulin-like growth factor binding protein-5, ciliary neurotrophic factor and neuropeptide Y (NPY) as being expressed by adipose tissue during pubertal development. These studies demonstrated for the first time the expression of several major adipokines or cytokines in pig adipose tissue which may influence local and central metabolism and growth. Leptin appears to be the primary metabolic signal and is part of the adipose tissue-hypothalamic regulatory loop in the control of appetite, energy homeostasis and luteinizing hormone (LH) secretion. Leptin's actions on appetite regulation are mediated by inhibition of hypothalamic NPY and stimulation of proopiomelanocortin. Its effects on gonadotropin-releasing hormone (GnRH)/LH secretion are mediated by NPY and kisspeptin. Thus, leptin appears to be an important link between metabolic status, the neuroendocrine axis and subsequent fertility in the gilt and sow.  相似文献   
23.
Cattle are fed moderate amounts of long chain fatty acids (FA) with the objective to enhance lactation and growth; however, recent interest on lipid feeding to cows has focused on reproduction, immunity and health. Increasing the caloric density of the ration by fat feeding has generally improved measures of cow reproduction, but when milk yield and body weight losses were increased by fat supplementation, positive effects on reproduction were not always observed. Feeding fat has influenced reproduction by altering the size of the dominant follicle, hastening the interval to first postpartum ovulation in beef cows, increasing progesterone concentrations during the luteal phase of the oestrous cycle, modulating uterine prostaglandin (PG) synthesis, and improving oocyte and embryo quality and developmental competence. Some of these effects were altered by the type of FA fed. The polyunsaturated FA of the n-6 and n-3 families seem to have the most remarkable effects on reproductive responses of cattle, but it is not completely clear whether these effects are mediated only by them or by other potential intermediates produced during rumen biohydrogenation. Generally, feeding fat sources rich in n-6 FA during late gestation and early lactation enhanced follicle growth, uterine PG secretion, embryo quality and pregnancy in cows. Similarly, feeding n-3 FA during lactation suppressed uterine PG release, and improved embryo quality and maintenance of pregnancy. Future research ought to focus on methods to improve the delivery of specific FA and adequately powered studies should be designed to critically evaluate their effects on establishment and maintenance of pregnancy in cattle.  相似文献   
24.
Focal intramural nodules were palpated in the rectal wall of a 12-year-old pony mare presented for rectal prolapse. Eosinophilic proctitis was diagnosed by examination of fine needle aspirates and biopsy of the largest rectal nodule. After treatment with a course of corticosteroids, the rectal nodule and accompanying peripheral eosinophilia resolved. There was no recurrence of the condition during the follow-up period of 20 months. Focal eosinophilic proctitis appeared to be an unusual cause of tenesmus and rectal prolapse in this case.  相似文献   
25.
Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.  相似文献   
26.
27.
Objective To assess the effect of amoxycillin treatment on urinary excretion of leptospires from cattle infected with Leptospira borgpetersenii serovar hardjo .
Design A chemotherapy trial with controls.
Procedure Fourteen heifers serologically negative to L hardjo were inoculated with L hardjo via the conjunctival route and assessed for evidence of infection by serological, fluorescent antibody and microbiological tests. Two injections (48 h apart) of amoxycillin at a dose of 15 mg/kg were administered intramuscularly to seven heifers 6.5 weeks after infection; the remaining heifers acted as untreated controls. Later, these seven control group heifers were treated with a single dose of amoxycillin (15 mg/kg). Samples of urine were collected before and after amoxycillin treatments; kidneys were collected at slaughter, and examined by fluorescent antibody test and microbiological culture.
Results Leptospires were isolated from the urine of 11 of 14 heifers inoculated with L hardjo . After treatment of six of these with two injections of amoxycillin, leptospires were not isolated. Of the controls, four of the five initially leptospiruric heifers continued to shed leptospires; after a single injection of amoxycillin, no leptospires were detected in the kidneys of these four.
Conclusion Amoxycillin may be an acceptable alternative to dihydrostreptomycin sulphate for the treatment of cattle infected with L hardjo .  相似文献   
28.
29.
ObjectiveTo compare the effects of tramadol alone, or in combination with dipyrone or meloxicam, on postoperative pain and analgesia requirement after unilateral mastectomy with or without ovariohysterectomy in dogs.Study designProspective, randomized, clinical study.AnimalsTwenty seven bitches undergoing unilateral mastectomy with or without ovariohysterectomy.MethodsAnesthesia was induced with propofol and maintained with isoflurane and a constant rate infusion of morphine. Before the end of surgery, dogs were randomly assigned to receive intravenous tramadol alone (3 mg kg?1, group T), combined with dipyrone (30 mg kg?1, group TD) or meloxicam (0.2 mg kg?1, group TM). Dogs received additional doses of tramadol (groups T and TM) or tramadol with dipyrone (group TD) at 8 and 16 hours after extubation. Postoperative pain was assessed by a blinded observer before anesthesia (baseline) and at 1, 2, 3, 4, 6, 8, 12, 16 and 24 hours after extubation using a visual analog scale (VAS) and a modified Glasgow scale. Rescue analgesia (morphine, 0.5 mg kg?1) was administered if the Glasgow pain score was >3.5.ResultsThere were no significant differences among groups in pain scores evaluated by the VAS or the Glasgow scale. In groups T, TD and TM, pain scores were significantly higher than at baseline for 6, 8 and 2 hours, respectively. Rescue analgesia was administered to 3/9, 2/9 and 1/9 dogs in groups T, TD and TM, respectively (p > 0.05) [Correction added on 15 August 2013, after first online publication: ‘T, TM and TD’ was changed to ‘T, TD and TM’.].Conclusions and clinical relevanceUnder the conditions of this study, tramadol alone or in combination with dypyrone or meloxicam provided effective analgesia for 24 hours in most dogs after unilateral mastectomy with or without ovariohysterectomy. Further evaluation of combination therapies is needed in larger groups of dogs.  相似文献   
30.
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