全文获取类型
收费全文 | 627篇 |
免费 | 38篇 |
专业分类
林业 | 37篇 |
农学 | 12篇 |
100篇 | |
综合类 | 53篇 |
农作物 | 17篇 |
水产渔业 | 25篇 |
畜牧兽医 | 360篇 |
园艺 | 21篇 |
植物保护 | 40篇 |
出版年
2023年 | 13篇 |
2022年 | 13篇 |
2021年 | 18篇 |
2020年 | 31篇 |
2019年 | 35篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 18篇 |
2014年 | 19篇 |
2013年 | 29篇 |
2012年 | 44篇 |
2011年 | 55篇 |
2010年 | 31篇 |
2009年 | 21篇 |
2008年 | 32篇 |
2007年 | 41篇 |
2006年 | 45篇 |
2005年 | 26篇 |
2004年 | 32篇 |
2003年 | 28篇 |
2002年 | 23篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1950年 | 1篇 |
排序方式: 共有665条查询结果,搜索用时 15 毫秒
181.
182.
183.
184.
Toepfer Stefan Kuhlmann Ulrich Kansiime Monica Onyango David Owino Davis Tamsin Cameron Katherine Day Roger 《植物病害和植物保护杂志》2019,126(2):103-106
Journal of Plant Diseases and Protection - This is an opinion paper to the perspective paper “The spread of the Fall Army Worm Spodoptera frugiperda in Africa—what should be done... 相似文献
185.
Factors associated with the outcome of peritonitis in horses are seldom described. The objectives of this study were to determine the common clinical signs and clinicopathologic findings and to reveal prognostic factors associated with the outcome of peritonitis in equine patients. Data were examined in a retrospective manner in 55 horses diagnosed with and treated for peritonitis. The most common clinical and clinicopathologic findings were tachycardia (94%), increased amount of peritoneal fluid on ultrasound (84%), altered mucous membranes (82%), bacteria noted on the direct smear (67%), hyperfibrinogenaemia (58%) and left shift (40%). The most commonly isolated organism was E. coli (37%). Survival rates were as follow: 78% in the whole study, 81% in the abdominal lavage group, 93% in the medically and 46% in the surgically managed groups. Complications were more common in the non-survivor group (P < 0.001). Initial haematocrit and surgical interventions were strongly associated with non-survival in the multivariate logistic regression model (P = 0.049, OR: 1.07 and P = 0.01, OR: 9.87, respectively). Prognosis of peritonitis without gastrointestinal rupture depends on the initial hydration status, surgical interventions and development of secondary complications, while other clinical and clinicopathologic findings do not appear to correlate with survival. Prospective evaluation of hydration and perfusion parameters and abdominal lavage warrants further investigation. 相似文献
186.
Katherine M.Halloran Emily C.Hoskins Claire Stenhouse Robyn M.Moses Kathrin A.Dunlap M.Carey Satterfield Heewon Seo Gregory A.Johnson Guoyao Wu Fuller W.Bazer 《畜牧与生物技术杂志(英文版)》2021,(3):952-971
Background: Administration of progesterone(P4) to ewes during the first 9 to 12 days of pregnancy accelerates blastocyst development by day 12 of pregnancy, likely due to P4-induced up-regulation of key genes in uterine epithelia responsible for secretion and transport of components of histotroph into the uterine lumen. This study determined if acceleration of blastocyst development induced by exogenous P4 during the pre-implantation period affects fetal-placental development on day 125 of pregnancy. Suffolk ewes(n = 35) were mated to fertile rams and assigned randomly to receive daily intramuscular injections of either corn oil vehicle(CO, n = 18) or 25 mg progesterone in CO(P4, n = 17) for the first 8 days of pregnancy. All ewes were hysterectomized on day 125 of pregnancy and: 1) fetal and placental weights and measurements were recorded; 2) endometrial and placental tissues were analyzed for the expression of candidate mRNAs involved in nutrient transport and arginine metabolism; and 3) maternal plasma, fetal plasma, allantoic fluid, and amniotic fluid were analyzed for amino acids,agmatine, polyamines, glucose, and fructose.Results: Treatment of ewes with exogenous P4 did not alter fetal or placental growth, but increased amounts of aspartate and arginine in allantoic fluid and amniotic fluid, respectively. Ewes that received exogenous P4 had greater expression of mRNAs for SLC7 A1, SLC7 A2, SLC2 A1, AGMAT, and ODC1 in endometria, as well as SLC1 A4, SLC2 A5, SLC2 A8 and ODC1 in placentomes. In addition, AZIN2 protein was immunolocalized to uterine luminal and glandular epithelia in P4-treated ewes, whereas AZIN2 localized only to uterine luminal epithelia in CO-treated ewes.Conclusions: This study revealed that exogenous P4 administered in early pregnancy influenced expression of selected genes for nutrient transporters and the expression of a protein involved in polyamine synthesis on day 125 of pregnancy, suggesting a ‘programming' effect of P4 on gene expression that affected the composition of nutrients in fetal-placental fluids. 相似文献
187.
188.
Dennis F. Lawler DVM AIan J. Templeton PhD Katherine L. Monti PhD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1993,7(6):383-387
Quantitative genetic evaluation of clinical dilated cardiomyopathy (DCM) was conducted in a large cattery with known history. Data showed that clinically affected cats were significantly more interrelated than randomly chosen case-control populations from the same colony. The results of this study suggest that quantitative inheritance, either interactive with or independent of nutrition or presently unknown factors, is involved in feline dilated cardiomyopathy. (Journal of Veterinary Internal Medicine 1993; 7:383–387. Copyright © 1993 by the American College of Veterinary Internal Medicine.) 相似文献
189.
190.
Katherine A. Houpt Sharon L. Smith 《The Canadian veterinary journal. La revue veterinaire canadienne》1981,22(4):77-81
In the laboratory situation the preferences of dogs and cats for food seem to be relatively uniform. Cats prefer fish and commercial cat food to rats. Dogs prefer beef, pork and lamb to chicken, liver and horsemeat and strongly prefer meat to cereal diets. They prefer canned meat to fresh meat, ground meat to cubed meat and cooked meat to raw meat. Canned or semimoist preparations are preferred to dry ones. Pet dogs have much more variable preferences according to their owner's subjective evaluation. A variety of factors seem to be related in an as yet unknown way to some flavor preferences of pet dogs, i.e. the dog's sex/reproductive status, weight and relationship to owners and the content of the dog's meals. The complicated interaction between (a) a pet's taste, texture and olfactory sensation, (b) its owner's perception of the pet and its preferences and (c) its physical and social environment deserves further investigation.
Obesity can result from endocrinological causes such as those following ovariohysterectomy, but most cases appear to be related to owner-induced variables. In a kennel situation most, but not all, dogs can be allowed free access to palatable food without becoming obese.
相似文献