全文获取类型
收费全文 | 247篇 |
免费 | 12篇 |
专业分类
林业 | 19篇 |
农学 | 2篇 |
95篇 | |
综合类 | 22篇 |
农作物 | 10篇 |
水产渔业 | 1篇 |
畜牧兽医 | 90篇 |
园艺 | 3篇 |
植物保护 | 17篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 13篇 |
2012年 | 12篇 |
2011年 | 22篇 |
2010年 | 7篇 |
2009年 | 8篇 |
2008年 | 13篇 |
2007年 | 12篇 |
2006年 | 8篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 15篇 |
2001年 | 3篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1986年 | 8篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 6篇 |
1971年 | 3篇 |
1970年 | 4篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1960年 | 1篇 |
1932年 | 1篇 |
1916年 | 1篇 |
排序方式: 共有259条查询结果,搜索用时 46 毫秒
1.
Studies on efficacy and stability of a vaccine bait containing ERA strain of rabies virus propagated in a BHK-21 cell line.
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)
K F Lawson H Chiu M Matson P Bachmann J B Campbell 《Canadian journal of veterinary research》1992,56(2):135-141
In a dose response study in foxes, the median protective dose of ERA BHK21 vaccine in a blister pack bait was 10(6.0) tissue culture infective doses (TCID)/mL, while artificially aged baits with titers of 10(6.3) TCID/mL induced seroconversion in 78% of foxes. There was no significant difference in the development of antibodies in foxes receiving 1, 2 or 3 mL volumes of vaccine in the bait. When baits were exposed to the elements and fed to foxes over a 21 day period, 85% of the animals seroconverted. Age, sex and the way in which the vaccine container was contacted did not appear to be factors in the responses of these animals. Juvenile foxes, approximately six months of age, were marked more readily with the tetracycline bait marker than older animals. Approximately 25% of foxes did not appear to respond well to vaccination and the titer of the vaccine was a critical factor in producing seroconversion in these animals. 相似文献
2.
Robert M. REES Juliette MAIRE Anna FLORENCE Nicholas COWAN Ute SKIBA Tony van der WEERDEN Xiaotang JU 《农业科学与工程前沿(英文版)》2020,7(1):75-80
Nitrous oxide (N2O) emissions make up a significant part of agricultural greenhouse gas emissions. There is an urgent need to identify new approaches to the mitigation of these emissions with emerging technology. In this short review four approaches to precision managements of agricultural systems are described based on examples of work being undertaken in the UK and New Zealand. They offer the opportunity for N2O mitigation without any reduction in productivity. These approaches depend upon new sensor technology, modeling and spatial information with which to make management decisions and interventions that can both improve agricultural productivity and environmental protection. 相似文献
3.
Wettability parameters determined for individual soils often show a considerable variation depending on the kind of sample (aggregated or homogeneous material) and the method used. To investigate the causes of this variation, we assessed wettability of both intact and crushed aggregates and bulk soil using different methods. Wettability of intact aggregates was characterized by a modified technique where the specific infiltration rates of water and a completely wetting liquid were used to define a repellency index. Contact angles were determined on crushed aggregates and bulk soil using the Wilhelmy plate and capillary rise methods. The repellency index was found to be sensitive to slight differences in wettability and was in good agreement with Wilhelmy plate contact angles. Contact angles measured with the capillary rise method showed a strong deviation from those determined with the Wilhelmy plate method. This can be ascribed to the underlying assumptions of the capillary rise method (i.e. cylindrical and parallel capillaries) resulting in an over‐estimation of contact angle, particularly for the small‐sized particle fraction because of the impact of inertia and pore structure. No significant differences were found between intact and crushed aggregates whereas the bulk soil was slightly more water‐repellent, probably because of a somewhat larger organic carbon content. We conclude that the contact angle determined by the Wilhelmy plate method and the repellency index are appropriate parameters for characterizing soil water repellency because they detected small changes in wettability over a wide range extending from subcritical water repellency to hydrophobicity. 相似文献
4.
Journal of Plant Diseases and Protection - The following text summarizes the different perspectives of presenters participating in the section Plant Protection in the Tropics and Subtropics, 61st... 相似文献
5.
6.
REASONS FOR PERFORMING STUDY: Studies on the prevalence of behavioural disorders in horses and on associated risk factors have revealed inconsistent results. There are many studies on the neuropharmacological, surgical or mechanical therapy of stereotypies, but little is known about their causation. OBJECTIVES: To explore risk factors associated with the occurrence of behavioural disorders in horses. METHODS: A sample of horse owners, selected randomly and representative for Switzerland, was contacted in a postal survey. Answers were provided for 622 stables (response rate 35.2%). Individual data of 2,341 horses were examined with path analysis (multivariable linear and logistic regression), and adjustment made for possible confounding effects due to age and breed. RESULTS: Out of 60 possible risk factors, 11 were associated with the outcome at the univariable level (null-hypothesis path model) and 3 factors remained after the backward logistic regression procedure. Mature Warmbloods and Thoroughbreds, assessed by the owners to be reactive, fed 4 times a day and without daily pasture, had increased odds of displaying crib-biting, weaving and box-walking. Furthermore, indirect associations of 5 factors with the outcome were identified. CONCLUSIONS: The final logistic regression model of risk factors leads to the hypotheses that causal prevention of stereotypic behaviours should be based upon housing and management conditions which allow tactile contact with other horses (e.g. mutual grooming), daily free movement (paddock or pasture), as well as the provision of high amounts of roughage but of little or no concentrates. POTENTIAL CLINICAL RELEVANCE: It is one of the aims of population medicine to prevent the development of behavioural disorders. Further research is needed to test the concluding hypotheses in experimental studies or to verify them in the context of similar observational studies. 相似文献
7.
Excretion and transmission of CSFV after vaccination with the CSF subunit marker vaccine "Porcilis Pesti" have been studied using the following different vaccination schedules: Group A--two vaccinations with an interval of 28 d, challenge 14 d after second vaccination (p.v2.); group B--two vaccinations with an interval of 14 d, challenge 14 d later; group C--two vaccinations with an interval of 28 d, challenge at time of booster vaccination; group D--two vaccinations with an interval of 14 d, challenge 7 d p.v2.; group E--single vaccination and infection 14 d later. After infection one sentinel pig was added to the vaccinated and infected pigs of each group. A single vaccination did not induce protective immunity against a CSFV challenge. Double vaccination at a four-week interval protected piglets from clinical infection, and neither viraemia and leukopenia nor virus excretion were detected if infected 14 d p.v2. Two vaccinations at a two-week interval followed by a challenge 7 d p.v2. led to a short viraemia on day 5 p.i. but without excretion of CSFV. Though all other vaccination schedules induced a reduction in virus shedding and a decrease in CSFV replication, in all these cases in-contact controls became infected. The results of transmission of CSFV are discussed in relation to a potential use of subunit marker vaccines in CSF control. 相似文献
8.
Jrg Bachmann 《植物养料与土壤学杂志》1998,161(6):699-699
9.
Volker Klaiber und Ute Seeling 《Forstwissenschaftliches Centralblatt》2002,121(6):267-282
Zusammenfassung: Die vorliegende Untersuchung hat zum Ziel, die Auswirkungen eines jahreszeitlich unterschiedlichen Einschlagszeitpunktes von Fichten (Winter- und Sommereinschlag) auf die Dimensionsstabilität des daraus erzeugten Schnittholzes zu erfassen und zu quantifizieren. Hierzu wurden jeweils 12 Fichten aus Winter- und Sommereinschlag unmittelbar nach der Aufarbeitung im Bestand zu Bauschnittholz in praxisüblichen Dimensionen verarbeitet. Die Erfassung der trocknungsbedingten Verwerfungen des Schnittholzes erfolgte mittels Vermessung der Kantholzform vor und nach einer technischen Kammertrocknung (Zielfeuchte u = 15 ± 3%). Dabei zeigte sich, dass der saisonal unterschiedliche Zeitpunkt der Fällung der Bäume keinen statistisch abgesicherten Einfluss auf die durchschnittlichen Verwerfungen bzw. die Dimensionsstabilität der daraus erzeugten Kanthölzer hatte. 相似文献
10.
Tom MISSELBROOK Zhaohai BAI Zejiang CAI Weidong CAO Alison CARSWELL Nicholas COWAN Zhenling CUI David CHADWICK Bridget EMMETT Keith GOULDING Rui JIANG Davey JONES Xiaotang JU Hongbin LIU Yuelai LU Lin MA David POWLSON Robert M. REES Ute SKIBA Pete SMITH Roger SYLVESTER-BRADLEY John WILLIAMS Lianhai WU Minggang XU Wen XU Fusuo ZHANG Junling ZHANG Jianbin ZHOU Xuejun LIU 《农业科学与工程前沿(英文版)》2022,9(3):475