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   74篇
  免费   6篇
林业   8篇
农学   3篇
基础科学   9篇
  23篇
综合类   5篇
农作物   2篇
水产渔业   2篇
畜牧兽医   17篇
植物保护   11篇
  2023年   1篇
  2022年   3篇
  2021年   1篇
  2020年   11篇
  2019年   2篇
  2018年   3篇
  2017年   9篇
  2016年   3篇
  2015年   1篇
  2014年   2篇
  2013年   7篇
  2012年   4篇
  2011年   8篇
  2010年   4篇
  2009年   2篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2001年   1篇
  1997年   2篇
  1996年   1篇
  1994年   2篇
  1992年   4篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
排序方式: 共有80条查询结果,搜索用时 15 毫秒
41.
Recent introduction of H5N1 highly pathogenic avian influenza virus (HPAIV) in wild birds from poultry in Eurasia signaled the possibility that this virus may perpetuate in nature. Surveillance of avian influenza especially in migratory birds, therefore, has been conducted to provide information on the viruses brought by them to Hokkaido, Japan, from their nesting lakes in Siberia in autumn. During 2008-2009, 62 influenza viruses of 21 different combinations of hemagglutinin (HA) and neuraminidase (NA) subtypes were isolated. Up to September 2010, no HPAIV has been found, indicating that H5N1 HPAIV has not perpetuated at least dominantly in the lakes where ducks nest in summer in Siberia. The PB2 genes of 54 influenza viruses out of 283 influenza viruses isolated in Hokkaido in 2000-2009 were phylogenetically analysed. None of the genes showed close relation to those of H5N1 HPAIVs that were detected in wild birds found dead in Eurasia on the way back to their northern territory in spring.  相似文献   
42.
Eugenol (1) and thymol (2) exhibit excellent fungicidal activity against pathogenic yeasts, including isolates resistant to azoles. The rapid irreversible action of compound-1 and compound 2 on fungal cells suggested a membrane-located target for their action. We investigated their effect on H+-ATPase mediated H+-pumping by various Candida species. Both compounds inhibit H+-ATPase activity at their respective MIC values — 500 and 100 μg/ml. Glucose stimulated H+-extrusion was also inhibited significantly by compound 1 and compound 2. Inhibition of H+-ATPase leads to intracellular acidification and cell death. Inhibition of cell growth and H+-efflux by test compounds suggests that their antifungal properties are related to their inhibitory effects on H+-ATPase.  相似文献   
43.
Cattle hypodermosis (warble fly infestation) is a notorious veterinary problem throughout the world. Larvae of Hypoderma species cause a subcutaneous myiasis of domesticated and wild ruminants. This disease is caused by, Hypoderma bovis, Hypoderma lineatum in cattle whereas, Hypoderma diana, Hypoderma actaeon, and Hypoderma tarandi, affect roe deer, red deer, and reindeer, respectively. Adults of the cattle grub are commonly known as heel flies, warble flies, bomb flies or gad flies. The biology of hypodermosis is complex because it passes through ecto- as well as endoparasitic stages in the life cycle. The parasitic stage of hypodermosis lasts about 1 year in domesticated as well as in the wild animals, while in the adult stage, a free-living fly lasts only for few days. The diagnosis of hypodermosis is of prime importance for planning treatment and the eradication program. Generally, there are two methods that are routinely used for diagnosis of hypodermosis, i.e., the direct clinical examination and immuno diagnosis by the use of pooled serum and/or milk sample. For the control of hypodermosis, different preparations are available and their use in most of the countries is limited to an individual level but never cover the whole cattle population of a country. Re-infestation in the herd occurs due to the untreated animals that remain the reservoir of the disease. The disease causes huge economic losses in animal production due to the effect of this disease on meat, milk, and the leather industry. It can also affect the general health status as well as the immune system of the body of the diseased animals. As regards the control measures of the disease, different methods have been efficiently practiced and consequently this disease is controlled at national level in many European countries.  相似文献   
44.
1. The present study was designed to analyse ochratoxin A (OTA) in poultry feed samples (mixed types) along with different poultry feed ingredients collected from different farms and market of Lahore, Pakistan.

2. The whole year (2012–2013) was divided into three sub-periods depending upon environmental conditions, that is, July–October (hot and humid), November–February (winter) and March–June (moderate). During each sub-period 120 samples were collected for each feed and each ingredient constituting a total of 840 samples (120x7 of feed and feed ingredients in each sub-period).

3. The results of this study indicated that the incidence of OTA-positive samples was highest in July–October followed by that during March–June while the incidence was minimum during November–February. Similarly, the largest number of samples was below the maximum tolerable level (MTL) during November–February followed by March–June while the least number of samples was below MTL during hot weather (July–October).

4. This is the first elaborative study regarding the levels of OTA in poultry feed and its ingredients collected from Lahore, Pakistan.  相似文献   

45.
The residual efficacy of diatomaceous earth alone and in combination with Beauveria bassiana (Balsamo) Vuillemin or a neonicotinoid insecticide thiamethoxam against Rhyzopertha dominica (Coleoptera: Bostrychidae) was studied under laboratory conditions. The mortality of adult R. dominica was decreased over the 9?months of storage period and the combined application of the test materials enhanced the mortality rates compared with alone treatments. The greatest mortality was observed in the combination of DE with thiamethoxam. Progeny suppression was decreased with the extended storage period. The maximum rate of mycosis and sporulation in the cadavers of R. dominica was observed where B. bassiana was applied alone at the lowest-dose rate. The results of this study indicate that all three control measures may provide safety for an extended period of time against R. dominica.  相似文献   
46.
Field experiments were conducted at Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan, to check the effect of polymer-coated diammonium phosphate (DAP) on maize–wheat cropping system. Different rates of polymer-coated and uncoated phosphorus (P) were applied first to maize then followed by wheat after harvesting of maize on same field. Results showed that application of 100% of recommended P from polymer-coated DAP increased plant height (10%), chlorophyll content (4%), biological yield (17%), grain yield (36%), agronomic efficiency (43%), and nitrogen, phosphorus, and potassium contents of maize produces, while in case of wheat 75% recommended P from polymer-coated DAP increased plant height (6%), chlorophyll content (18%), biological yield (20%), grain yield (14%), agronomic efficiency (72%), and nitrogen, phosphorus, and potassium contents of grains and straw as compared with uncoated DAP. So, it can be summarized that polymer-coated DAP can effectively improve growth, yield, and phosphorus-use efficiency of maize and wheat crop.  相似文献   
47.
48.
Mosquito netting side panels of targets used for tsetse control were treated with lambda-cyhalothrin, either dissolved in a mixture of acetone and a chlorohydrocarbon oil, ‘Cereclor’® > (ICI, UK) or as a conventional wettable powder formulation suspended in water. Treated netting samples were weathered under natural conditions in full sun in Zimbabwe. Following brief tarsal contact of test insects (adults of Glossina morsitans morsitans Westw.) with treated netting, the wettable powder induced 100% knockdown for four months after treatment but 24-hour mortality levels were reduced from the third month onwards. The oil formulation induced 100% knockdown for up to ten months following treatment and 100% mortality at 24 hours for up to eight months. Chemical assay showed that after two months there had been a rapid reduction in the amount of active ingredient to only 20% of that applied using the wettable powder, whereas the oil formulation took seven months to fall to this level. Provided that at least 5% of the original amount of pyrethroid remained on the fabric it was quite effective and the superiority of the oil formulation was further enhanced by the observation that the starting concentration was only 25% of that of the wettable powder.  相似文献   
49.
Salt tolerance is a physiologically and genetically complex trait controlled by multiple genes. To analyze the genetic basis of salt tolerance we evaluated 18 F1 along with their nine parents under three salt stress levels i.e. control, 10 dS m−1 and 15 dS m−1 in the summer of 2017 and 2018. Data were recorded for the number of bolls, seed cotton yield, boll weight, Na+, K+, K+/Na+ ratio, H2O2, SOD, POD, CAT and TSP. Line × tester analysis indicated that the contribution of lines was greater than testers. Except for Na+, most of the traits were controlled by non-additive genes. With the rise of salt stress, SCA variances increased and were higher than GCA variances for most of the traits indicating the traits were controlled by a few largely dominant genes. KEHKSHAN, FH-118 and FH-114 were found good general combiner whereas the cross KEHKSHAN × FH-114 was a good specific combiner and also indicated significant better parent heterosis for most traits during two years under salt stress and can be utilized in a breeding programme for salt tolerance.  相似文献   
50.
Random amplified polymorphic DNA (RAPD) markers were used to estimate the genetical variability of three salt-resistant genotypes, SARC-1, SARC-5 and S-24, exposed to saline environment. High-yielding and salt-sensitive variety MH-97 was used as standard for comparison. The behavior of these genotypes under saline environment was analyzed by using the hydroponics screening methods at the seedling stage. One hundred and fifty primers were tested of which 52 primers revealed differences between SARC-1 and SARC-5, 54 revealed differences between SARC-1 and S-24 and 61 revealed differences between SARC-5 and S-24. Polymorphism differences between MH-97 and SARC-1, MH-97 and SARC-5 and MH-97 and S-24 were 53%, 64% and 42%, respectively. Four primer pairs amplified special fragments, which were located in all the three salt-resistant genotypes but none on the salt-sensitive genotype MH-97. Primer GLD-15 (5?-CCGTGGCATT-3?) generated a prominent fragment of length 1460 bp; primer GLF-18 (5?-ACCCGGAACC-3?) produced a fragment of length nearly 980 bp in the salt-resistant genotype; the primer pair GLE-5 (5?-TTCAAGCCCG-3?) located one polymorphic amplified band of 1290 bp and the primer GLH-9 (5?-ATCCAGGTCA-3?) performed as a weak polymorphic band of 640 bp, respectively.  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