全文获取类型
收费全文 | 1134篇 |
免费 | 111篇 |
专业分类
林业 | 59篇 |
农学 | 24篇 |
基础科学 | 1篇 |
215篇 | |
综合类 | 92篇 |
农作物 | 53篇 |
水产渔业 | 51篇 |
畜牧兽医 | 600篇 |
园艺 | 35篇 |
植物保护 | 115篇 |
出版年
2023年 | 12篇 |
2022年 | 9篇 |
2021年 | 37篇 |
2020年 | 30篇 |
2019年 | 46篇 |
2018年 | 28篇 |
2017年 | 30篇 |
2016年 | 24篇 |
2015年 | 26篇 |
2014年 | 42篇 |
2013年 | 49篇 |
2012年 | 80篇 |
2011年 | 89篇 |
2010年 | 46篇 |
2009年 | 44篇 |
2008年 | 85篇 |
2007年 | 77篇 |
2006年 | 64篇 |
2005年 | 56篇 |
2004年 | 56篇 |
2003年 | 43篇 |
2002年 | 54篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1993年 | 5篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1971年 | 3篇 |
1967年 | 6篇 |
1966年 | 4篇 |
1964年 | 3篇 |
1963年 | 4篇 |
1962年 | 5篇 |
1961年 | 5篇 |
1960年 | 8篇 |
1959年 | 7篇 |
1958年 | 5篇 |
1955年 | 8篇 |
1932年 | 4篇 |
排序方式: 共有1245条查询结果,搜索用时 93 毫秒
121.
Lefebvre R Theoret C Doré M Girard C Laverty S Vaillancourt D 《The Canadian veterinary journal. La revue veterinaire canadienne》2005,46(11):1029-1033
An 8-year-old Arabian mare was admitted for a large ovarian anovulatory follicle. A clinical diagnosis of ovarian tumor and endometritis was established. Histological examinations revealed an ovarian teratoma and a grade II endometritis. Three months after unilateral ovariectomy, the mare was confirmed pregnant and eventually gave birth uneventfully. 相似文献
122.
Bleul UT Schwantag SC Bachofner C Hässig MR Kähn WK 《Journal of the American Veterinary Medical Association》2005,226(7):1119-1123
OBJECTIVE: To determine milk flow, somatic cell counts (SCCs), and the incidence of clinical mastitis in cows that had undergone theloresectoscopy for treatment of teat stenosis caused by mucosal detachment in the region of the streak canal or Fürstenberg's rosette. DESIGN: Retrospective study. ANIMALS: 52 cows with teat stenosis that were treated via theloresectoscopy. PROCEDURE: Medical records of eligible cows were reviewed. Additional data regarding milking ease, SCC, development of clinical mastitis of the affected gland, and whether the cow remained in the herd were collected via owner-completed questionnaires. RESULTS: 49 of 52 questionnaires were completed. At referral, teat sinusitis was diagnosed in 29 of 52 cows. Milk flow was normal in 38 of 41 treated teats at discharge and in 24 of 40 during the next lactation. Thirteen of 49 cows were culled during the next lactation because of abnormal udder health. High SCC and teat sinusitis at referral and development of clinical mastitis during the 10-day period after surgery resulted in high SCCs in the remainder of the current lactation. The incidence of clinical mastitis during the remainder of the current and during the next lactation was higher in cows that had teat sinusitis at the time of surgery, compared with those that did not. CONCLUSIONS AND CLINICAL RELEVANCE: Teat stenoses resulting from mucosal lesions in the region of the streak canal or Fürstenberg's rosette may be successfully treated via theloresectoscopy. Inflammation of the teat sinus and gland at the time of surgery may adversely affect udder health. 相似文献
123.
Ex vivo whole blood stimulation with endotoxin has proved to be a useful method for quantitative evaluations of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) response ability in humans. In the present study, a dose- and time-response study was carried out in order to develop an ex vivo whole blood stimulation assay for the quantification of TNF-alpha production in pigs. The TNF-alpha response was enhanced with increasing endotoxin stimulation dose. The maximum TNF-alpha response occurred after 2-8 h of stimulation. Subsequently, the assay was used to evaluate the TNF-alpha response in pigs (n=32) in relation to weaning. The TNF-alpha response was 332 pg ml(-1) (+/-59 pg) plasma 2 days before weaning and 127 pg ml(-1) (+/-23 pg) plasma 2 days after weaning, which was a significant reduction (p<0.001). Total and differential counts of leucocytes were the same before and after weaning. Thus the lower TNF-alpha response may be due to reduced monocyte responsiveness to the endotoxin, rather than caused by a reduction in monocyte numbers. The reduced TNF-alpha response in piglets after weaning may be a factor of importance to the increased disease susceptibility seen in piglets in this period. 相似文献
124.
McCann ME Rickes EL Hora DF Cunningham PK Zhang D Brideau C Black WC Hickey GJ 《American journal of veterinary research》2005,66(7):1278-1284
OBJECTIVE: To determine cyclooxygenase (COX)-2 selectivity, pharmacokinetic properties, and in vivo efficacy of firocoxib (ML-1,785,713) in cats. ANIMALS: 5 healthy male and 14 healthy female domestic shorthair cats. PROCEDURE: Selectivity of firocoxib for inhibiting COX-2 was determined by comparing the potency for inhibiting COX-1 with that of COX-2 in feline blood. Pharmacokinetic properties were determined after i.v. (2 mg/kg) and oral (3 mg/kg) administration in male cats. In vivo efficacy was evaluated in female cats with lipopolysaccharide (LPS)-induced pyrexia with administration of firocoxib 1 or 14 hours before LPS challenge. RESULTS: Blood concentrations resulting in 50% inhibition of COX-1 and COX-2 activity in vitro were 75 +/- 2 microM and 0.13 +/- 0.03 microM, respectively, and selectivity for inhibiting COX-2 relative to COX-1 was 58. Firocoxib had moderate to high oral bioavailability (54% to 70%), low plasma clearance (4.7 to 5.8 mL/min/kg), and an elimination half-life of 8.7 to 12.2 hours. Firocoxib at doses from 0.75 to 3 mg/kg was efficacious in attenuating fever when administered to cats 1 or 14 hours before LPS challenge. CONCLUSIONS AND CLINICAL RELEVANCE: Firocoxib is a potent COX-2 inhibitor and is the only selective COX-2 inhibitor described for use in cats to date. It is effective in attenuating febrile responses in cats when administered 14 hours before LPS challenge, suggesting it would be suitable for once-a-day dosing. Because selective COX-2 inhibitors have an improved therapeutic index relative to nonselective nonsteroidal anti-inflammatory drugs in humans, firocoxib has the potential to be a safe, effective anti-inflammatory agent for cats. 相似文献
125.
Dirofilaria immitis, the etiological agent for heartworm disease, is a zoonotic, vector-borne parasite. The dog is the most common natural host. Heartworm disease is present in all US states, as well as in South and Central America, Asia, Europe, Africa and Australia [. Prevalence of feline heartworm disease - a global review. In: Proceedings of the Heartworm Symposium'95, Auburn, Alabama, USA, 31 March-2 April, 1995. American Heartworm Society, Batavia, USA, pp. 79-86]. According to Menda [Menda, J.A., 1989. Transplacental migration of Dirofilaria immitus microfilariae. Companion Anim. Pract. 19 (6-7), 18-20], 18% of the canine population in the city of Santo Domingo tested positive for heartworm using the Filar Assay Kit. In the year 2000, clinical veterinarians from the Samana Peninsula in the Dominican Republic stated that the incidence of heartworm was minimal (Goodman, personal communication). In this small epidemiological study performed during the summer of 2001, 104 dogs from the Samana Peninsula were tested for heartworm antigen with the WITNESS HW Test and a wet mount evaluation for microfilaria under light microscopy. It was found that 18.2% of the canine population tested positive according to either one or both of the diagnostic methods. It would be advisable to apply prevention measures to control Dirofilaria immitis infection in the canine population of the Samana Peninsula in the Dominican Republic. 相似文献
126.
127.
Kreuder C Miller MA Lowenstine LJ Conrad PA Carpenter TE Jessup DA Mazet JA 《American journal of veterinary research》2005,66(2):289-299
OBJECTIVE: To describe cardiac lesions and identify risk factors associated with myocarditis and dilated cardiomyopathy (DCM) in beach-cast southern sea otters. ANIMALS: Free-ranging southern sea otters. PROCEDURE: Sea otters were necropsied at the Marine Wildlife Veterinary Care and Research Center from 1998 through 2001. Microscopic and gross necropsy findings were used to classify sea otters as myocarditis or DCM case otters or control otters. Univariate, multivariate, and spatial analytical techniques were used to evaluate associations among myocarditis; DCM; common sea otter pathogens; and potential infectious, toxic, and nutritional causes. RESULTS: Clusters of sea otters with myocarditis and DCM were identified in the southern aspect of the sea otter range from May to November 2000. Risk factors for myocarditis included age, good body condition, and exposure to domoic acid and Sarcocystis neurona. Myocarditis associated with domoic acid occurred predominantly in the southern part of the range, whereas myocarditis associated with S. neurona occurred in the northern part of the range. Age and suspected previous exposure to domoic acid were identified as major risk factors for DCM. A sample of otters with DCM had significantly lower concentrations of myocardial L-carnitine than control and myocarditis case otters. CONCLUSIONS AND CLINICAL RELEVANCE: Cardiac disease is an important cause of death in southern sea otters. Domoic acid toxicosis and infection with S. neurona are likely to be 2 important causes of myocarditis in sea otters. Domoic acid-induced myocarditis appears to progress to DCM, and depletion of myocardial L-carnitine may play a key role in this pathogenesis. 相似文献
128.
Studies of Johne's Disease in Canada: XII. Electrophoretic Analysis of Changes in Serum Proteins in Infected Cattle and Sheep
下载免费PDF全文
![点击此处可从《Canadian journal of veterinary research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Delma Cochrane Christine E. Rice J. Carrière 《Canadian journal of veterinary research》1965,29(8):209-213
Electrophoretic examinations were made on sera collected monthly for a period of eleven months from ten cattle naturally or experimentally infected with Johne''s bacilli and from ten contact sheep. With one exception, the percentage estimates for the four major classes of serum proteins, albumin, alpha1-, alpha2-, beta- and gamma-globulins did not differ significantly in sera from infected and non-infected, presumably healthy cattle. One cow with a persistently high complement-fixing titre with Johne''s bacillus antigen, showed an exceptionally high proportion of gamma-globulin in its serum. The percentage of gamma-globulin tended to be higher in sera of contact sheep than in that of normal sheep sera but the monthly variation in the relative proportion of these and other globulins showed no evident relationship to the fluctuations observed in the specific complement-fixing and anti-complementary properties of these sera. 相似文献
129.
The Effect of Unheated Normal Bovine Serum on the Complement-Fixing Activity of Heat Inactivated Bovine Antiserum with Homologous Antigen: III. Immunodiffusion Studies
下载免费PDF全文
![点击此处可从《Canadian journal of veterinary research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Christine E. Rice 《Canadian journal of veterinary research》1962,26(9):212-217
Examination by immuno-diffusion methods in agar gel plates demonstrated that the supplementing fraction precipitated from normal bovine serum by dialysis against dilute buffer, pH 5.0 to 6.6, contains at least three main antigens, and a weaker fourth. Two of these antigens or antigen determinants appeared to be present in globulin fractions prepared by dilution with distilled water or differential precipitation with ammonium or sodium sulphate. 相似文献
130.