全文获取类型
收费全文 | 259篇 |
免费 | 1篇 |
专业分类
林业 | 16篇 |
基础科学 | 1篇 |
12篇 | |
综合类 | 191篇 |
农作物 | 5篇 |
水产渔业 | 3篇 |
畜牧兽医 | 30篇 |
植物保护 | 2篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 5篇 |
2011年 | 8篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 27篇 |
2007年 | 24篇 |
2006年 | 29篇 |
2005年 | 27篇 |
2004年 | 26篇 |
2003年 | 19篇 |
2002年 | 27篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1960年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有260条查询结果,搜索用时 15 毫秒
81.
Holden C 《Science (New York, N.Y.)》2002,295(5563):2202-2203
82.
83.
Investigation on the use of 0.3% tacrolimus lotion for canine atopic dermatitis: a pilot study 总被引:1,自引:0,他引:1
The efficacy of 0.3% tacrolimus lotion (maximum dosage: 0.3 mg kg-1 per day) for treatment of atopic dermatitis (AD) was evaluated. Systemic absorption and effects on complete blood cell counts (CBC) and chemistry panels were also investigated. Eight dogs were assigned randomly to either a tacrolimus or a vehicle lotion treatment group. Both owners and investigator were blinded to the treatment. After 4 weeks, there was a 2-week wash-out period and treatments were reversed. Owners scored pruritus weekly while the investigator scored pruritus and erythema at the beginning and end of each treatment period. Investigator scores for pruritus in the tacrolimus group significantly decreased by the end of the study (P = 0.03). Investigator scores for erythema in the tacrolimus group were significantly lower than those in the placebo group at the end of the study (P = 0.005). There was no difference between groups with respect to owner scores for pruritus. No changes in the CBC and chemistry panels were noted. Mean blood concentrations of tacrolimus were below toxic levels. 相似文献
84.
Akucewich LH Philman K Clark A Gillespie J Kunkle G Nicklin CF Greiner EC 《Veterinary parasitology》2002,109(1-2):129-139
Ectoparasites are a common and important cause of skin disorders in cats. Ectoparasites are capable of disease transmission and can cause life-threatening anemia in young or debilitated animals. The objective of this study was to determine the potential feline ectoparasites in domestic cats by using a cohort of feral cats from north central Florida that have not received veterinary care and have no known exposure to insecticide application. A total of 200 feral cats were randomly selected for this study. Four monthly sessions were scheduled for feral cat ectoparasite examination and sample collection. Five minutes flea combing revealed that 185/200 (92.5%) of the cats were infested with fleas. The cat flea, Ctenocephalides felis was the most common flea infesting 92.5% feral cats (mean = 13.6; standard deviation +/- 16.4 fleas per cat). Pulex simulans was identified on 9/200 (4.5%) (mean = 1 +/- 0.50 fleas per cat). Echidnophaga gallinacea was found on 11/200 (5.5%) of cats (mean = 14.8 +/- 9.63 fleas per cat). There was a significant difference (P = 0.0005) in the average number of C. felis counted per cat between months. Mean counts in June (18.3 +/- 2.4) and July (16.6 +/- 2.1) were significantly (P < 0.01) higher than in August (8.4 +/- 2.5) and September (7.7 +/- 2.0). Only 15/200 cats had skin disease. Flea infestation may potentially be the underlying cause in 10/15. Otoscopic examination of both ears revealed mite movement and black ceruminous exudate typically indicative of the presence of Otodectes cynotis in 45/200 (22.5%) cats. Examination of a swab specimen from both ear canals of all cats revealed O. cynotis in 74/200 (37%) cats. Of 74 cats positive on ear swab, 8 (10.8%) showed a normal ear canal appearance (no or mild ceruminous exudate) in both ears upon otoscopic examination. A total of nine ticks were recovered from five cats. The number and species of ticks recovered were: one adult female Rhipicephalus sanguineus; one adult female Amblyomma americanum; one adult male A. americanum; five adult female Dermacentor variabilis; and one adult female Ixodes scapularis. All superficial skin scrapes were negative. Hair clippings from the abdomen of all cats revealed 2/200 (1%) of the cats were infested with Felicola subrostratus. 相似文献
85.
Constance L 《Science (New York, N.Y.)》1983,222(4628):1113-1114
86.
Carrie J. Ewing Constance E. Hausman John Pogacnik Jason Slot Pierluigi Bonello 《Forest Pathology》2019,49(2)
Beech leaf disease (BLD) is a currently undiagnosed and seemingly lethal disease that was discovered in 2012 on American beech trees (Fagus grandifolia) in north‐east Ohio in the United States. Since its discovery, BLD has spread rapidly and can now be found in forests in 10 counties in Ohio, eight counties in Pennsylvania and five counties in Ontario, Canada. The initial symptoms of the disease appear as a dark green, interveinal banding pattern on the lower canopy foliage. These initial symptoms typically occur in the shrub or sampling layer of a beech stand. The later symptoms result in solidly darkened leaves that are shrunken and crinkled. The symptoms appear to progress through the buds as the affected buds are eventually aborted and no new leaves are produced. We fear this disease has the potential to drastically alter the Eastern deciduous forests of the United States on its own and through potential compounding disease effects. In addition, BLD poses a threat to global forests as symptoms of the disease were detected on European (F. sylvatica) and Oriental (F. orientalis) beech species in nurseries in north‐eastern Ohio. Due to its rapid spread and variability in environmental conditions where it has been detected, it seems unlikely that BLD is an abiotic disorder. Thus, intense efforts are underway to determine the causal agent of BLD. Relevant stakeholders are advised to be alert for BLD symptoms in beech forests in the Northern Hemisphere, and substantial resources should be invested in understanding this emerging forest disease. 相似文献
87.
88.
89.
90.
Regulating the global fisheries: The World Wildlife Fund, Unilever, and the Marine Stewardship Council 总被引:1,自引:1,他引:0
This analysis uses an analytical frameworkgrounded in political economy perspectives of theglobalization of the agro-food sector combined with acase study approach focusing on the Marine StewardshipCouncil (MSC) to inform discussions regarding thecharacteristics of societal regulation in thepost-Fordist era. More specifically, this analysisuses the case of the emergence of the MSC toinvestigate propositions regarding the existence of,and location of, nascent forms of a transnationalState. The MSC proposes to regulate the certificationof sustainable fisheries at the global level throughan eco-labeling program. The MSC was created in 1996by the transnational environmental organization theWorld Wildlife Fund and the transnational corporationUnilever. The emergence of the MSC has generatedheated discussion in fisheries management circles thatis in general divided along North/South lines. Thisanalysis indicates that the case of the MSC providesvaluable insights into the possible characteristics ofsupranational regulatory mechanisms that might emulatethe role of the nation-State in the post-Fordist era. 相似文献