全文获取类型
收费全文 | 565篇 |
免费 | 33篇 |
专业分类
林业 | 31篇 |
农学 | 8篇 |
基础科学 | 4篇 |
43篇 | |
综合类 | 83篇 |
农作物 | 23篇 |
水产渔业 | 14篇 |
畜牧兽医 | 347篇 |
园艺 | 7篇 |
植物保护 | 38篇 |
出版年
2018年 | 5篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 28篇 |
2012年 | 17篇 |
2011年 | 21篇 |
2010年 | 10篇 |
2009年 | 12篇 |
2008年 | 29篇 |
2007年 | 14篇 |
2006年 | 21篇 |
2005年 | 20篇 |
2004年 | 21篇 |
2003年 | 29篇 |
2002年 | 22篇 |
2001年 | 20篇 |
2000年 | 13篇 |
1999年 | 17篇 |
1998年 | 5篇 |
1997年 | 13篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 9篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1970年 | 6篇 |
1968年 | 5篇 |
1967年 | 6篇 |
1940年 | 4篇 |
1932年 | 3篇 |
排序方式: 共有598条查询结果,搜索用时 31 毫秒
1.
2.
3.
Outbreaks of infection due to a parapoxvirus were reported on eight New Zealand deer farms. Scabby lesions were seen variably on the muzzle, lips, face, ears and neck of red deer (Cervus elaphus) with morbidity rates reaching 100%. On three farms multifocal lesions were also present on the velvet. Deaths were reported on two properties where the lesions were extensive and secondary bacterial infections had occurred. On one of these farms multifactorial disease was suspected. Poxvirus particles were seen by negative contrast electron microscopy in scab material from all eight properties. Morphologically the deer virus resembled a parapoxvirus, but restriction endonuclease analysis showed its DNA fragment patterns were distinct from those of orf (contagious ecthyma) virus. 相似文献
4.
Schneider RR Hunter DB 《The Canadian veterinary journal. La revue veterinaire canadienne》1993,34(2):103-108
A study of the pattern and relative frequency of diseases in adult female mink during the lactation period was undertaken. All adult females that died between parturition (April/May) and July 1, 1990, from 48 farms in southern Ontario were selected for study, and the cause of death was determined by gross necropsy. In addition, the cause of death was determined by gross necropsy for all adults and weaned kits that died on one farm between April 1988 and March 1989.
The mortality rate among farms in the 1990 study, for adult females during the lactation period, ranged from 0.2% to 10.1%, with a median of 1.9%. Nursing disease (56%) was the most common diagnosis, followed by mastitis (11%), metritis (8%), and dystocia (7%). Escherichia coli and Staphylococcus spp. were the most frequent isolates from the cases of mastitis. In the 1988/1989 study, the mortality rate was highest from May to July, with a large increase in June as a result of nursing disease.
相似文献5.
6.
We have measured endometrial oxytocin receptor concentrations during prepuberty in ewe lambs, and have investigated the effect of progesterone on the activity of these receptors. In the first study, oxytocin receptor concentrations were undetectable in 2-week prenatal lambs but had increased immediately following birth and were then maintained throughout prepubertal life. Despite the presence of oxytocin receptors animals showed no prostaglandin F(2alpha) (PGF(2alpha)) release in response to exogenous oxytocin challenge at either 3 or 5 months of age. In a second study in 4-month-old ewe lambs treatment with exogenous progesterone resulted in the appearance of PGF(2alpha) release in response to oxytocin after 10 days of treatment. Thus, during the prepubertal life, ewe lambs possess the prerequisites of a luteolytic mechanism in that they have a dormant population of oxytocin receptors in which progesterone can induce oxytocin-stimulated PGF(2alpha) release. 相似文献
7.
Adrian Mutlow Ramiro Isaza James W Carpenter David E Koch Robert P Hunter 《Journal of zoo and wildlife medicine》2004,35(4):489-496
Using a crossover study design, the pharmacokinetics of carfentanil and naltrexone after i.v., i.m., and s.c. administration were determined in eight domestic goats (Capra hircus). Serial blood samples were taken up to 120 hr after carfentanil administration, and the plasma drug concentrations were determined using liquid chromatography and mass spectroscopy. All goats were immobilized with 40 microg/kg carfentanil i.m., although the resulting neurologic effects varied considerably. Plasma profiles showed rapid carfentanil absorption and a simple biphasic decline for 12-48 hr. Naltrexone given at 100 mg naltrexone/mg carfentanil 30 min after carfentanil administration produced rapid reversal of immobilization after all routes of administration. Variable fluctuations in the naltrexone plasma concentrations during the first 2.5-3.5 hr were observed, followed by a more consistent biphasic decline. The time to standing was significantly shorter after i.v. compared with s.c. naltrexone, although the time difference (1 min) had little clinical relevance. No statistically significant differences between the naltrexone pharmacokinetic parameters measured for the three routes of naltrexone administration were identified, although the recoveries after i.m. administration were, subjectively, the smoothest. The carfentanil half-life did not differ significantly in the goats given naltrexone by different routes. Although it is currently recommended that the naltrexone dose be divided into s.c. and i.v. portions, this practice does not appear to offer any benefit. 相似文献
8.
AIM: To report on the isolation and identification of canine adenovirus type-2 (CAV-2) from a greyhound dog with tracheitis/tonsillitis. METHODS: Virus isolation was performed with Madin and Darby canine kidney (MDCK) cell monolayers using standard virological techniques. The isolated virus was identified by haemagglutination inhibition and serum neutralisation tests. Viral DNA was extracted from infected MDCK cells and subjected to restriction endonuclease analysis using the endonuclease enzymes Bam HI, Bgl II, Eco RI and Hind III. RESULTS: A virus, designated 5 113-87, was isolated in MDCK cells yielding typical cytopathic effect. The virus could be neutralised with a CAV-2 specific reference antiserum and also showed some cross neutralisation with CAV-1 specific reference antiserum. The virus 5 113-87 had a high haemagglutination inhibition titre with CAV-2 antiserum using human group 0 red blood-cells and CAV-1 and CAV-2 reference antisera. This virus also had DNA restriction profiles identical to those of the reference CAV-2 (Toronto A26/61), whereas previously isolated strains of adenovirus from dogs in New Zealand had DNA restriction patterns identical to the prototype CAV-1 strain (Utrecht). CONCLUSION: The findings show that the virus 5 113-87 isolated from the upper respiratory tract of a dog in New Zealand is CAV-2. 相似文献
9.
Hunter J. Piegols Brittany E. Abrams Janis M. Lapsley Megan T. Cray Josephine A. Dornbusch Christina Murphy Brandan G. Wustefeld-Janssens Carlos H. Souza Marine Traverson Pierre Amsellem Elroy Williams Owen T. Skinner Julius M. Liptak Julie A. Stephens Laura E. Selmic 《Veterinary and comparative oncology》2023,21(4):673-684
Adrenalectomies for canine adrenal tumours are associated with peri-operative morbidity and mortality. Objectives of this study included assessing the prognostic value of tumour- or surgery-related variables in predicting peri-operative mortality and overall survival in dogs undergoing adrenalectomies for primary adrenal tumours as well as pre-treatment with phenoxybenzamine on survival to discharge with pheochromocytomas specifically. A multi-institutional retrospective cohort study was performed across nine institutions. Electronic medical record searches identified 302 dogs which met the inclusion criteria. Data collected included dog-related, tumour-related, treatment-related, surgery-related, and outcome variables. Univariate and multivariable logistic regression and cox proportional hazards models were used to identify variables associated with death prior to discharge and tumour-related survival. Overall, 87% of dogs survived to discharge with a tumour-related survival time of 3.96 years. Post-operative complications were reported in 25%. Increased surgical time (p = 0.002) and pre-surgical medical treatment other than phenoxybenzamine (p = 0.024) were significantly associated with increased peri-operative mortality while ureteronephrectomy (p = 0.021), post-operative pancreatitis (p = 0.025), and post-operative aspiration pneumonia (p < 0.001) were significantly associated with decreased overall survival. Phenoxybenzamine pretreatment had no effect on peri-operative mortality. Thirty-seven of 45 (82%) dogs with pheochromocytomas not pretreated survived to discharge, and 50 of 59 (85%) dogs with pheochromocytomas pretreated with phenoxybenzamine survived to discharge (p = 0.730). This study provides information on risk factors for death prior to discharge and tumour-related survival that may help guide clinical management and owner expectations. In addition, the study findings challenge the previously reported benefit of phenoxybenzamine for pretreatment of dogs undergoing adrenalectomies for pheochromocytomas. 相似文献
10.
Summary Lucerne was irrigated for three years on a slowly permeable, duplex soil, with saline water up to 2.4 dS m–1 without significant yield decline. Irrigation water of 4.5 dS m–1 significantly reduced yield. Lucerne yield was most closely related to the soil ECe of the 0–15 cm depth, rather than the total rootzone, and was described by; Relative yield=100–6.5 (ECe-2.1). While lucerne roots reached depths of at least 150 cm, approximately 80% of total root length was located in the 0–60 cm depth.Increasing salinity increased the plant concentrations of sodium and chloride, however, these changes were not closely related to changes in yield.Soil salinity increased with increasing salinity of the applied water. However, during the irrigation season water penetration and the accumulation of salt within the profile was predominantly restricted to the 0–60 cm depth. No portion of the applied irrigation water was available as a leaching fraction. Any leaching of salts to the watertable, particularly below 120 cm, was due to winter rainfall rather than the application of summer irrigation water.Ripping the soil to a depth of 75 cm increased water infiltration and resulted in increased crop yields, but did not significantly affect the crop relative yield-soil ECe relationship.From the results it is proposed that on the slowly permeable duplex soils, when watertable depth is controlled, management strategies for lucerne irrigated with saline water should be based on controlling the salinity of the shallow soil depths, to 60 cm. 相似文献