全文获取类型
收费全文 | 140篇 |
免费 | 17篇 |
专业分类
林业 | 1篇 |
农学 | 1篇 |
基础科学 | 1篇 |
6篇 | |
综合类 | 25篇 |
农作物 | 1篇 |
水产渔业 | 3篇 |
畜牧兽医 | 109篇 |
园艺 | 2篇 |
植物保护 | 8篇 |
出版年
2020年 | 2篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 2篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1962年 | 1篇 |
1893年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 31 毫秒
11.
João H Perotta Paulo A Canola Maristela CS Lopes Patrícia M Évora Paulo EB Martinez André Escobar Carlos AA Valadão 《Veterinary anaesthesia and analgesia》2014,41(4):357-364
ObjectiveTo evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses.Study designRandomized, crossover experimental study.AnimalsEight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years.MethodsBaseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2oAV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO2) and oxygen (PaO2) were obtained 5 minutes before administration of IV hyoscine (0.14 mg kg?1; group HIV), IM hyoscine (0.3 mg kg?1; group HIM), or an equal volume of physiologic saline IV (group C). Five minutes later, medetomidine (7.5 μg kg?1) was administered IV and measurements were recorded at various time points for 130 minutes.ResultsMedetomidine induced bradycardia, 2oAV blocks and increased SVR immediately after administration, without significant changes in CI or MAP in C. Hyoscine administration induced tachycardia and hypertension, and decreased the percentage of 2oAV blocks induced by medetomidine. Peak HR and MAP were higher in HIV than HIM at 88 ± 18 beats minute?1 and 241 ± 37 mmHg versus 65 ± 16 beats minute?1 and 192 ± 38 mmHg, respectively. CI was increased significantly in HIV (p ≤ 0.05). Respiratory rate decreased significantly in all groups during the recording period. pH, PaCO2 and PaO2 were not significantly changed by administration of medetomidine with or without hyoscine.Conclusion and clinical relevanceHyoscine administered IV or IM before medetomidine in horses resulted in tachycardia and hypertension under the conditions of this study. The significance of these changes, and responses to other dose rates, requires further investigation. 相似文献
12.
13.
A number of insecticides used for ectoparasite control in the livestock industry were screened for their efficacy against larvae of the screw-worm fly, Chrysomya bezziana, using in vivo and laboratory tests. Proprietary screw-worm fly treatments (after exposure to outdoor conditions for up to 10 days) were also tested against eggs and adults of C bezziana. Three of these were also evaluated on naturally acquired screw-worm infestations. Residual protection was generally of short duration. Among the organophosphorus compounds, the most effective formulations contained relatively high concentrations (3 to 4% al) of coumaphos, 2.5% fenchlorphos or low concentrations (0.05 to 0.5% al) of diazinon, chlorfenvinphos and fenthion methyl. Two chlorinated hydrocarbon insecticides containing 3% lindane and 5% dieldrin were very effective but are now prohibited for use in Australia. Preparations had serious deficiencies when used under field conditions, especially for treating large, deepseated myiases for which systemic insecticides are recommended. A comparison of methods demonstrated that a laboratory test could supersede live animal experimentation, at least for the initial screening of potential insecticides. 相似文献
14.
15.
Isotope fractionation and atmospheric oxygen: implications for phanerozoic O(2) evolution 总被引:1,自引:0,他引:1
Berner RA Petsch ST Lake JA Beerling DJ Popp BN Lane RS Laws EA Westley MB Cassar N Woodward FI Quick WP 《Science (New York, N.Y.)》2000,287(5458):1630-1633
Models describing the evolution of the partial pressure of atmospheric oxygen over Phanerozoic time are constrained by the mass balances required between the inputs and outputs of carbon and sulfur to the oceans. This constraint has limited the applicability of proposed negative feedback mechanisms for maintaining levels of atmospheric O(2) at biologically permissable levels. Here we describe a modeling approach that incorporates O(2)-dependent carbon and sulfur isotope fractionation using data obtained from laboratory experiments on carbon-13 discrimination by vascular land plants and marine plankton. The model allows us to calculate a Phanerozoic O(2) history that agrees with independent models and with biological and physical constraints and supports the hypothesis of a high atmospheric O(2) content during the Carboniferous (300 million years ago), a time when insect gigantism was widespread. 相似文献
16.
17.
18.
DH Lowndes DB Geohegan AA Puretzky DP Norton CM Rouleau 《Science (New York, N.Y.)》1996,273(5277):898-903
Pulsed laser deposition (PLD) is a conceptually and experimentally simple yet highly versatile tool for thin-film and multilayer research. Its advantages for the film growth of oxides and other chemically complex materials include stoichiometric transfer, growth from an energetic beam, reactive deposition, and inherent simplicity for the growth of multilayered structures. With the use of PLD, artificially layered materials and metastable phases have been created and their properties varied by control of the layer thicknesses. In situ monitoring techniques have provided information about the role of energetic species in the formation of ultrahard phases and in the doping of semiconductors. Cluster-assembled nanocrystalline and composite films offer opportunities to control and produce new combinations of properties with PLD. 相似文献
19.
Amounts of spray drifting downwind from a field sprayer applying picloram or paraquat were determined and compared with the damage done to bean and barley plants. Measurements downwind of a stationary spray-boom showed that drift increases rapidly with both wind speed and boom height. It was concluded that it is possible to set a safe distance downwind for the application of a herbicide which affects plants only in the wetted areas but with a sensitive crop and many growth-regulating materials this will be very difficult. 相似文献
20.
John R. Lake 《Pest management science》1977,8(5):515-520
The sizes and velocities of drops in sprays from farm sprayers are considered in relation to their impaction on plant surfaces. Examples from a study being carried out at the National Institute of Agricultural Engineering (NIAE) are given. The results showed that young leaves of barley (cv Mazurka) and wild oats (Avena fatua L.) were difficult to wet, only the smallest drops applied (about 100 um diameter) being readily retained. In the context of weed control in cereals the importance of detrmining the effect of the form of plant deposits on herbicidal activity is discussed, and examples of results of a joint study between the NIAE and the Agricultural Research Council Weed Research Organization are given. 相似文献