全文获取类型
收费全文 | 667篇 |
免费 | 15篇 |
专业分类
林业 | 47篇 |
农学 | 7篇 |
基础科学 | 2篇 |
83篇 | |
综合类 | 268篇 |
农作物 | 15篇 |
水产渔业 | 35篇 |
畜牧兽医 | 163篇 |
园艺 | 17篇 |
植物保护 | 45篇 |
出版年
2023年 | 9篇 |
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 23篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 15篇 |
2013年 | 15篇 |
2012年 | 46篇 |
2011年 | 49篇 |
2010年 | 28篇 |
2009年 | 19篇 |
2008年 | 53篇 |
2007年 | 53篇 |
2006年 | 66篇 |
2005年 | 54篇 |
2004年 | 38篇 |
2003年 | 34篇 |
2002年 | 34篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1966年 | 2篇 |
1958年 | 1篇 |
1954年 | 1篇 |
1944年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有682条查询结果,搜索用时 15 毫秒
81.
M Adrian B Grant M Ratzlaff J Ray C Boulton 《American journal of veterinary research》1977,38(4):431-435
Electrogoniometry was used qualitively and quantitatively to assess the movements of the normal and pathologic metacarpophalangeal joints of selected horses. A total of 4 Thoroughbreds, 1 normal and 3 with clinical and radiographic changes in the metacarpophalangeal joints of 1 limb, were evaluated at the walk and trot. Goniograms of the affected joints were compared with those of the normal horse and the normal contralateral metacarpophangeal joint. Qualitative asymmetry was recognized on the goniograms, and the ranges of motion were quantified and related to the clinical and radiologic observations. 相似文献
82.
83.
84.
ABSTRACT Rhizomania disease of sugar beet represents a major economic threat to the sugar industry in the United Kingdom. Here we use the UK rhizomania epidemic as an exemplar of a range of highly infectious spatially heterogeneous diseases. Using a spatially explicit stochastic model, we investigated the efficacy of a spectrum of possible control strategies, both locally reactive and national in character. These include the use of novel cultivars of beet with different responses to infection, changes in cultivation practice, and reactive containment policies at the farm scale. We show that strictly local responses, including a containment policy similar to that initially implemented in the United Kingdom in response to the disease, are largely ineffective in slowing the spread because they fail to match the natural scale of the epidemic. Larger spatial-scale processes are considerably more successful. We conclude that epidemics have intrinsic temporal and spatial scales that must be matched by any control strategy if it is to be both effective and efficient. We have generated probability distributions for the proportion of farms symptomatic. Over the course of the epidemic, such distributions develop a bimodality that we hypothesize to correspond to the matching of spatial heterogeneity in the susceptible population to the intrinsic scales of the epidemic. 相似文献
85.
86.
87.
88.
Mellema SC Doherr MG Wechsler B Thueer S Steiner A 《Veterinary journal (London, England : 1997)》2006,172(2):274-283
To assess short- and long-term effects of bloodless castration methods with and without local anaesthesia, behavioural and cortisol responses of lambs were used as indicators of pain and distress. Seventy lambs, aged 2-7 days, were control-handled or castrated by Burdizzo or rubber ring methods with and without local anaesthesia. Either 5 mL of diluted lidocaine (4 mg/kg) or physiological sodium chloride solution was distributed in both spermatic cords and the scrotal neck. The serum cortisol response was monitored for 48 h, and behavioural and clinical traits were followed for three months. Local anaesthesia tended to reduce behavioural and cortisol responses after Burdizzo castration and provided a significant reduction after rubber ring castration. Prolonged pain after rubber ring castration with anaesthesia was not evident. If combined with local anaesthesia, both the rubber ring and the Burdizzo methods are acceptable methods for castration of lambs up to one week of age. 相似文献
89.
Cho A 《Science (New York, N.Y.)》2006,313(5795):1872-1875
90.
Owen AM Coleman MR Boly M Davis MH Laureys S Pickard JD 《Science (New York, N.Y.)》2006,313(5792):1402
We used functional magnetic resonance imaging to demonstrate preserved conscious awareness in a patient fulfilling the criteria for a diagnosis of vegetative state. When asked to imagine playing tennis or moving around her home, the patient activated predicted cortical areas in a manner indistinguishable from that of healthy volunteers. 相似文献