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   146篇
  免费   4篇
林业   10篇
  55篇
综合类   11篇
农作物   13篇
水产渔业   8篇
畜牧兽医   40篇
园艺   4篇
植物保护   9篇
  2023年   1篇
  2022年   3篇
  2021年   4篇
  2020年   3篇
  2019年   4篇
  2018年   1篇
  2016年   3篇
  2015年   5篇
  2014年   4篇
  2013年   6篇
  2012年   17篇
  2011年   16篇
  2010年   6篇
  2009年   6篇
  2008年   7篇
  2007年   9篇
  2006年   16篇
  2005年   11篇
  2004年   4篇
  2003年   5篇
  2002年   2篇
  2001年   5篇
  1999年   2篇
  1998年   2篇
  1996年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1981年   1篇
  1968年   1篇
  1958年   2篇
排序方式: 共有150条查询结果,搜索用时 15 毫秒
1.
Pharmacokinetic and clinical effectiveness of liposome-encapsulated N-methylglucamine antimoniate (LMA) was performed in dogs suffering from experimental leishmaniosis. LMA was compared with N-methylglucamine antimoniate (MGA), the same drug in its free form. Sb plasma concentrations for LMA were always higher than those for MGA. Mean residence time (MRT), half-life time (t(1/2)) and clearance (Cl) showed that Sb was eliminated slower after liposome administration. The high volume of distribution (Vd) obtained with LMA suggests that Sb could achieve therapeutic concentrations in parasite-infected tissues. Average plasma concentration at steady state (Css(ave)) shows that Sb body concentrations after LMA treatment (9.8 mg/kg Sb, each 24h) would be effective in Leishmania infantum canine infection. Comparing LMA with MGA in a 1-year follow-up we observed no relapses for LMA and total protein and gammaglobulin concentrations were within normal range, while for MGA both began to rise 3 months after treatment. Use of antimonial liposomal formulations may restore effectiveness to an existing drug and reduce toxicity.  相似文献   
2.
A nested polymerase chain reaction (PCR) assay was developed using primers selected from the genomic DNA of Leishmania infantum and applied to the diagnosis of leishmaniosis in peripheral blood in dogs. Blood of 39 dogs of different breeds, all sampled in Catalonia (Spain), were tested for leishmaniosis by enzyme linked immunosorbent assay (ELISA), western blotting (WB) and peripheral blood mononuclear cell (PBMC) culture and nested PCR. Twenty negative controls (healthy dogs less than 1-year-old that had not been exposed to a sandfly season) were also studied. Nineteen of the 39 dogs studied were positive by ELISA and/or WB, and 18 of these had a positive PBMC nested PCR. PBMC nested PCR was negative in all the remaining animals that were negative by serological examination, including the 20 negative controls. Parasitological examination and nested PCR of bone marrow and lymph node aspirate from the 19 dogs positive by serological examination, were also positive. These results indicate that PBMC nested PCR is a sensitive and specific tool to diagnose leishmaniosis in dogs. The use of PBMC has the advantage over bone marrow and lymph node aspirates in that it is a less invasive sample.  相似文献   
3.
4.
In the present study a technique was developed with the aim of guaranteeing the composition and security of fish meals, since it allows verification of whether these meals contain land animal remains. The method is based on polymerase chain reaction (PCR) and length polymorphism, followed by a restriction fragment length polymorphism (RFLP). Specific primers for every species were designed and calibrated, generating exclusively a PCR product with a specific size when DNA for each species was present in the sample. This technique allows the detection of land animal remains in fish meals, specifically cow, chicken, pig, horse, sheep, and goat. The identity of the PCR products can be confirmed by RFLP analysis using only one restriction enzyme. The selected restrictase generated one characteristic restriction profile for every species included in this study. The detection limit of this method was calculated by using mixtures of fish meals in different proportions and meal that exclusively contained remains of one of these land species studied. The analytical strategy herein proposed was applied to fish and meat meals, giving good results, both in the analyzed standards and in commercial samples.  相似文献   
5.
Osmotic dehydration was assessed as an operation for supplementing a solid foodstuff (a gel was used as the model food) with grape phenolics from a concentrated red grape must to increase its antioxidant properties. The model food was processed for up to 24 h, and the osmotic pressure was adjusted by diluting the concentrated red grape must. In all conditions tested, low molecular weight phenolics (相似文献   
6.
Journal of Pest Science - Conservation biological control involves manipulation of the environment to enhance the effectiveness of natural enemies in controlling crop pests. In this study, we...  相似文献   
7.
The focus of this review is the response of insulin and glucagon to various experimental and physiological conditions in fish. Circulating levels of insulin and glucagon have been analyzed in several fish species, principally salmonids. It is generally accepted that, in fish, the insulin secretion in response to amino acids is stronger than to glucose, although this information has been obtained mainly from carnivorous species. Studies of other species demonstrate that the alimentary pattern affect hormonal secretion and should be taken into account when the effects of secretagogues are analyzed. There are few studies of glucagon secretion, even in salmonids, although it is known that amino acids also stimulate its release. The level of this response and its relationship to insulin secretion depends upon the species of fish. We will discuss the significance of these observations, while also considering other important factors, including the influence of neuropeptides and interactions with other pancreatic and gastro-intestinal hormones. Finally, seasonal, temperature and reproductive stage effects will be discussed, all of which should be taken into account when attempting to understand the role of pancreatic hormones in fish. This short review will not cover the action of these hormones on their target tissues.  相似文献   
8.
Polyunsaturated aldehydes (PUAs) are organic compounds mainly produced by diatoms, after cell wounding. These compounds are increasingly reported as teratogenic for species of grazers and deleterious for phytoplanktonic species, but there is still scarce information regarding concentration ranges and the composition of PUAs in the open ocean. In this study, we analyzed the spatial distribution and the type of aldehydes produced by the large-sized (>10 μm) phytoplankton in the Atlantic Ocean surface. Analyses were conducted on PUAs released after mechanical disruption of the phytoplankton cells, referred to here as potential PUAs (pPUAs). Results show the ubiquitous presence of pPUA in the open ocean, including upwelling areas, as well as oligotrophic gyres. Total pPUA concentrations ranged from zero to 4.18 pmol from cells in 1 L. Identified PUAs were heptadienal, octadienal and decadienal, with heptadienal being the most common (79% of total stations). PUA amount and composition across the Atlantic Ocean was mainly related to the nitrogen:phosphorus ratio, suggesting nutrient-driven mechanisms of PUA production. Extending the range of trophic conditions considered by adding data reported for productive coastal waters, we found a pattern of PUA variation in relation to trophic status.  相似文献   
9.
The spectrum and dynamics of xylophagous insects infesting Pinus pinaster after a fire event were studied from November 2007 to December 2008 at Sierra de Outes (Galicia, NW Spain). Insects were collected within and outside the fire area. Relationships among species status, species abundance, tree parameters and tree injury were assessed. Mortality of injured trees was also recorded. Insect colonization built up consistently during the first year after the fire, although the pests did not colonize unburned trees in nearby areas. Thirteen insect species from six xylophagous families were collected. Tomicus spp., Buprestis novenmaculata, Anobium punctatum and Pissodes castaneus were the first species detected. Tomicus spp. (29%) and Ips sexdentatus (23%) were the dominant taxa. Bole char height and soil burn severity were positively correlated with insect presence. Trees with short stem diameter and thinner bark were also preferred. B. novenmaculata presence was positively correlated with crown scorch. Loss of cambium hydration was negatively related to the occurrence of pests, likely because sapwood desiccation and loss of nutrient impede brood development. About 33.3% of the fire-scorched pines died. The results recommend the removal of injured and dying pines after fire, to avoid the rise of pest population threatening recovering trees in the burned areas.  相似文献   
10.
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