首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   69篇
  免费   0篇
林业   3篇
  28篇
综合类   9篇
水产渔业   1篇
畜牧兽医   23篇
园艺   3篇
植物保护   2篇
  2023年   1篇
  2021年   2篇
  2019年   4篇
  2017年   2篇
  2014年   2篇
  2013年   4篇
  2012年   4篇
  2011年   9篇
  2010年   1篇
  2009年   5篇
  2008年   6篇
  2007年   4篇
  2006年   7篇
  2005年   3篇
  2004年   2篇
  2003年   4篇
  2000年   1篇
  1998年   1篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1984年   1篇
  1981年   1篇
排序方式: 共有69条查询结果,搜索用时 31 毫秒
1.
2.
3.
Nine isolates ofBacillus thuringiensis Berliner belonging to var.kenyae, var.aizawai and var.entomocidus, were bioassayed against 1st instar larvae ofBoarmia (Ascotis) selenaria Schiffermüller and compared withB. thuringiensis var.kurstaki, HD-1-S-1980. None were found to have a higher potency than HD-1-S-1980, which is used for commercial control of young larvae of this pest in avocado plantations in Israel.  相似文献   
4.
5.
OBJECTIVE: To estimate the impact of choosing food products labelled either as low or high in salt on salt intake in the Finnish adult population. SETTING AND SUBJECTS: The National FINDIET 2002 survey with 48-hour recalls from 2007 subjects aged 25-64 years. Sodium intake was calculated based on the Fineli food composition database including the sodium content of natural and processed foods as well as the salt content of recipes. The distribution of salt intake was calculated in different ways: the present situation; assuming that all breads, cheeses, processed meat and fish, breakfast cereals and fat spreads consumed would be either 'lightly salted' or 'heavily salted' based on the current labelling practice; and, in addition, assuming that all foods would be prepared with 50% less or more salt. RESULTS: Excluding underreporters, the mean salt intake would be reduced by 1.8 g in men and by 1.0 g in women if the entire population were to choose lightly salted products and further by 2.5 and 1.8 g, respectively, if also salt used in cooking were halved. Choosing heavily salted products would increase salt intake by 2.1 g in men and by 1.4 g in women. In the worst scenarios, salt intake would be further increased by 2.3 g in men and by 1.6 g in women. CONCLUSIONS: These calculations show that the potential impact of labelling and giving consumers the possibility to choose products with less salt is of public health importance. In addition, strategies to reduce the salt content of all food groups are needed.  相似文献   
6.
Canine idiopathic pulmonary fibrosis is a chronic, progressive interstitial lung disease particularly prevalent in West Highland White Terriers. In the present prospective pilot study, we evaluated the feasibility of modified VetMousetrap? device in high resolution CT to detect idiopathic pulmonary fibrosis in West Highland White Terriers. Twelve awake West Highland White Terriers with canine idiopathic pulmonary fibrosis and 24 clinically healthy West Highland White Terriers were scanned using a helical dual slice scanner utilizing VetMousetrap? device without or with minimal chemical restraint with butorphanol. Three evaluators blindly assessed the images for image quality and the presence of canine idiopathic pulmonary fibrosis related imaging findings such as ground glass opacity and reticular opacities. Additionally, the attenuation of the lung was quantified with ImageJ software using histogram analysis of density over the lung fields. Computed tomography was successfully completed and motion artifact ranked in statistical analysis barely noticeable to mild in all dogs. The agreement between imaging findings and clinical status was very good with overall κ value 0.91 and percentage of agreement of 94%. There was also very good intraobserver (κrange = 0.79‐0.91) and interobserver agreement (κ = 0.94). Moderate to severe ground glass opacity was present in all affected dogs. In the ImageJ analysis, a significant difference in lung attenuation between the study groups was observed. We conclude that modified VetMousetrap? device is applicable in diagnosing canine idiopathic pulmonary fibrosis in awake West Highland White Terriers avoiding anesthetic risk in these often severely hypoxic patients.  相似文献   
7.
We examined the quality and decomposition of naturally abscised leaves of silver birch (Betula pendula) seedlings subjected to three different levels of fertilization under ambient and elevated levels of temperature and CO2. At the end of the second growing season, the chemical composition of the litter collected from the seedlings was analyzed. Whole-leaf samples from pooled litter from each of the four replicates from each treatment were put in mesh bags and transferred to ambient climate in the field. The remaining mass of litter was measured by sampling bags in May and October throughout the four-year incubation period. Fertilization with all nutrients decreased the initial carbon and tannin contents of litter, and increased the proportion of the fast-decomposing fraction, but still fertilization slowed down the decomposition of this fraction. Initially, the estimated proportion of the fast-decomposing fraction was smallest in elevated CO2 + temperature, and largest in ambient climate. During decomposition, elevated growth-temperature slowed down decomposition of the fast fraction under ambient CO2 but increased it under elevated CO2. The changes in litter decomposition rates found over four years were not very large. However, we conclude that the interactions of different factors lead to different results than if the factors had been studied separately, and future studies should take interactions into account.  相似文献   
8.
The compensation point of bidirectional NOx fluxes of plants is often determined in chamber measurements by varying the NOx concentration and searching for the point where the net flux is zero. We hypothesized that the compensation point can vary with changing conditions so much that one constant value is not sufficiently accurate. The compensation point for NOx fluxes of Scots pine was analysed with a model describing the NOx consumption and production processes. Consumption was assumed to occur via the stomata and on needle surfaces, with the rate depending on ambient concentration and degree of stomatal opening. Production was assumed to occur on the needle surfaces depending on solar UV-A irradiance. We used NOy flux data measured with two gas-exchange chambers in southern Finland to parameterize the model. The estimated compensation points increased with increasing UV-A irradiance and decreased with increasing stomatal conductance. With open stomata, it varied several ppb even under field conditions.  相似文献   
9.
10.
This study investigated the effects of allergic skin disease on the penetration kinetics of hydrocortisone through canine skin in vitro. Full-thickness lesional and nonlesional (normal) skin was removed from the dorsal lumbosacral and dorsocaudal thoracic regions, respectively, of five canine cadavers. The dogs were suspected of having flea allergy dermatitis based on their distribution and types of skin lesions. Nonlesional skin was confirmed to be histologically normal, and the histopathology of the lesional skin was consistent with allergic dermatitis. Excised skin was clipped, mounted in Franz-type diffusion cells, and the transdermal penetration of a saturated, radiolabelled hydrocortisone solution was measured over 30 h. When the penetration data for all five dogs were pooled, a restricted (or residual) maximal likelihood mixed model predicted that the permeability coefficient and pseudosteady-state flux of hydrocortisone was more than twice as great (95% confidence interval 1.55-2.71 times as great; P < 0.0001) through lesional compared with nonlesional skin. There was no significant difference in the lag time for hydrocortisone penetration through lesional compared with nonlesional skin of the dogs. This study has confirmed that the transdermal penetration of hydrocortisone may be altered, typically increased twofold, but could be as high as 10-fold, through lesional compared with nonlesional skin of dogs with suspected flea allergy dermatitis. This is likely to be affected by variables such as disease severity, concurrent infections and interindividual differences in skin characteristics.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号