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   125篇
  免费   5篇
林业   7篇
农学   17篇
  18篇
综合类   6篇
农作物   10篇
水产渔业   12篇
畜牧兽医   49篇
园艺   1篇
植物保护   10篇
  2023年   1篇
  2022年   3篇
  2021年   4篇
  2020年   7篇
  2019年   4篇
  2018年   5篇
  2017年   3篇
  2016年   11篇
  2015年   2篇
  2014年   1篇
  2013年   9篇
  2012年   8篇
  2011年   8篇
  2010年   9篇
  2009年   3篇
  2008年   9篇
  2007年   5篇
  2006年   6篇
  2005年   4篇
  2004年   3篇
  2003年   3篇
  2002年   5篇
  2001年   5篇
  2000年   1篇
  1999年   5篇
  1998年   1篇
  1994年   1篇
  1990年   1篇
  1989年   1篇
  1987年   1篇
  1973年   1篇
排序方式: 共有130条查询结果,搜索用时 0 毫秒
91.
A total of 113 diarrheic samples comprising of 68 buffalo calves and 45 cow calves were screened by RNA-PAGE for the detection of presence of rotavirus. RNA-PAGE analysis of these samples revealed 11 (9.73%) was found positive for rotavirus. Out of 68 faecal samples of buffalo calves tested for viral gastroenteritis, 8 (11.76%) were found positive for rotavirus. Similarly, out of 45 faecal samples of cattle calves tested for viral gastroenteritis, 3 (6.66%) was found positive for rotavirus. Rotavirus-positive samples represented long electropherotype. All RNA-PAGE-positive faecal samples for rotavirus subjected to RT-PCR for VP7 gene, ten samples yielded a specific product of 1,013 bp of VP7 gene. All the PCR-positive samples of the present study were subjected to genotyping with primers for G6, G8 and G10 genotype. All positive samples showed G10 genotype. This indicates that G10 may be predominant genotype among bovine calves in Mumbai region in India.  相似文献   
92.
Herein, an intelligent cotton fabric was fabricated using a non-ionic surfactant based macro structured carbonaceous coating through the ‘knife-over-roll’ technique. The developed novel fabric was tested as flexible, mechanically robust with prolonged chemical/moisture resistance. Various characterization techniques were thoroughly used to analyze the fabric. The as-prepared fabric shows an outstanding electromagnetic interference (EMI) shielding efficiency (SE) of about 21.5 dB even at the lowest possible coating thickness (0.20 mm) where the highest EMI SE of 30.8 dB is obtained at only 0.30 mm coating thickness over the X-band frequency range (8.2-12.4 GHz), possibly due to the three-dimensionally interconnected network structure of conducting carbon particles. The micro-computed tomography disclosed the porous architecture and “void-filler” arrangement within the fabrics. For the betterment of serviceability and practicability of the coated fabric, the water tolerance and contact angle studies were conducted. The relatively high contact angle than pure cotton fabric, and excellent water resistance after coating ensure improved endurance for external or industrial uses. Therefore, this proof-of-construct manifests commercialization of the developed fabric for multipurpose applications in a facile, less-hazardous and economical way.  相似文献   
93.
Mondal SN  Timmer LW 《Phytopathology》2002,92(12):1267-1275
ABSTRACT Mycosphaerella citri, the cause of citrus greasy spot, produces pseudothecia and ascospores in decomposing leaf litter on the grove floor. In laboratory studies, the effect of wetting and drying and temperature on the formation, maturation, and production of pseudothecia and ascospores was evaluated on mature, detached grapefruit leaves. Production of pseudothecia was most rapid when leaves were soaked five times per week for 2 h per day, but pseudothecial density and total ascospore production were greatest when leaves were soaked three times per week for 2 h per day. In duration of wetting studies, 3 h per day, 3 days per week brought about the most rapid production, but 10 to 30 min per day resulted in production of the most pseudothecia and ascospores. Pseudothecia and ascospore production were greatest at 28 degrees C and declined rapidly at lower and higher temperatures. Maturation of pseudothecia was slow at 20 and 24 degrees C, but production was high at 24 degrees C; at 32 degrees C, pseudothecia matured rapidly, but degenerated quickly. No mature pseudothecia were produced on leaves maintained continuously under wet conditions. In field studies, leaves were placed on the grove floor monthly from April 2000 to September 2001. Pseudothecia production was rapid during the summer rainy season from June to September. Pseudothecia produced on leaves placed in the grove from October to May developed and matured more slowly but were produced in much larger numbers than in summer. The number of days to first pseudothecial initials, 50% maturation, first discharge of ascospores, leaf decomposition, as well as pseudothecial density and incidence, were negatively related to average temperature. Total ascospore production was unrelated to temperature.  相似文献   
94.
Concern about the impact of pesticides on both health and environment has resulted in the search for alternative control measures for stored-product insect pest. Amongst such alternatives are insect growth regulators (IGRs), a class of biorational compounds that disrupt the normal development of insects. Because of their selectivity of action, these compounds appear to fit the requirements for Third Generation Pesticides, environmentally benign and safer grain protectants. IGRs have been developed commercially and are being used to control insect pests in agriculture, forestry, public health and stored products. IGRs affect the biology of treated insects, for example, both embryonic and post-embryonic development, reproduction, behaviour and mortality. Abnormal morphogenesis is the observed effect of IGR action on the insects. Many of them are more potent than current insecticides, even against the eggs.Compared with the conventional insecticides, IGRs do not exhibit quick knock-down in insects or cause mortality, but the long-term exposure to these compounds largely stops the population growth, as a result of the effects mentioned in both the parents and progeny.The present paper focuses on the previous works on different IGRs available commercially. Also, their possible role in the management of stored-product insect pests has been discussed.  相似文献   
95.
Citrus scab, caused by Elsinoë fawcettii (anamorph Sphaceloma fawcettii), is a common foliar fungal disease affecting many citrus cultivars, including grapefruit. No commercial grapefruit cultivar is resistant to scab, and the disease results in severely blemished fruit which reduces its marketability. Transgenic ‘Duncan’ grapefruit trees expressing the antimicrobial attE gene were produced via Agrobacterium-mediated transformation. In in vitro leaf and greenhouse assays, several transgenic-lines had significantly lower susceptibility to E. fawcettii compared to the non-transformed control (P?P?P?attE mRNA was inversely related to the number of copies detected by Southern blot. The least susceptible line had a single inserted copy of the attE transgene whereas more susceptible lines had multiple copies. Since the attacin mode of action was thought to be specific to Gram-negative bacteria, it was unexpected to find that there was a significant activity against E. fawcettii.  相似文献   
96.
Journal of Soils and Sediments - Huge amounts of radiocesium, radiostrontium, and fission products were released into the atmosphere during the Fukushima Daiichi Nuclear Power Plant (FDNPP)...  相似文献   
97.
The effects of dietary administration of inorganic zinc (zinc sulphate, ZnSO4) and nano zinc (zinc oxide nanoparticles, ZnO‐NP) were evaluated in rohu, Labeo rohita fingerlings. Fish were fed with a basal diet (Control) supplemented with ZnSO4 (T1, T2 and T3) and ZnO‐NP (T4, T5 and T6) at 10, 20 and 30 mg/kg, respectively, for a duration of 45 days. The results revealed that fish fed diet containing 20 mg ZnO‐NP per kg (T5) had the highest weight gain and specific growth rate (SGR, % per day), which was significantly different (p < .05) from the other experimental diets. Significantly (p < .05), higher activities of the digestive and metabolic enzymes were recorded in the fish fed ZnO‐NP containing diets as compared to the diets containing inorganic Zn or control diet. The maximum serum glucose and protein levels were noted in fish reared on diet T5. Both SGOT and SGPT activities were significantly increased in fish fed Zn‐supplemented diets (T1 to T6), as compared to the control group. Similarly, innate immune parameters were improved with feeding Zn incorporated diets. The highest phagocytic (40.74 ± 0.65%) and respiratory burst (0.33 ± 0.001, OD 630nm) activities were recorded in the fish fed diet containing ZnO‐NPs at 20 mg/kg (T5). The maximum superoxide production and serum peroxidase activity were detected in the fish fed T5 and T6 diets. Overall, results indicated that short‐duration feeding (≤45 days) of dietary ZnO‐NP (20 mg/kg) improved growth, enzyme activity, serum biochemical parameters and immune function in rohu fingerlings.  相似文献   
98.
Understanding biodiversity and community composition is a prerequisite to sustainable exploitation and conservation of fisheries. We assessed the spatial and seasonal patterns of fish community composition and biodiversity in seasonal no-take riverine sanctuaries in Bangladesh, which aim to conserve the anadromous hilsa shad (Tenualosa spp. and Hilsa keele). Fish samples were collected during monsoon, as well as pre- and postmonsoon, from five sites within two sanctuaries and one site in an open fishing area. Although total abundance was similar along the rivers, species richness was significantly higher at the open fishing site due to its connectivity to nearby habitats. The diversity apparently decreased in a downstream direction. Fish communities at two upstream sites were separated from other sites in multivariate space largely due to higher abundance of hilsa at downstream sites and presence of floodplain-oriented species at the two upstream sites. Short body length and high trophic level at all sites indicated that fish communities were overexploited. Our results also indicated that riverine hilsa sanctuaries in Bangladesh are rich in fish species diversity and support several threatened species designated by the International Union for Conservation of Nature (IUCN). Our study also suggested that since hilsa abundance shapes community patterns, it can therefore impact riverine ecosystem functioning in the sanctuary areas. The findings of this study can serve as an important baseline for future biodiversity assessment, conservation and impact assessment of conservation in rivers, and therefore help to establish multispecies ecosystem-based management of riverine fisheries around the world.  相似文献   
99.
Molecular diversity and association of simple sequence repeat (SSR) markers with rust and late leaf spot (LLS) resistance were detected in a set of 20 cultivated groundnut genotypes differing in resistance against both diseases. Out of 136 bands amplified from 26 primers, 104 were found polymorphic (76.5%). Cluster analysis (UPGMA) revealed two main clusters separated at 52% Jaccard's similarity coefficient according to disease reaction to rust and LLS. Based on the Kruskal–Wallis one-way anova and simple regression analysis three and four SSR alleles were found associated with rust and LLS resistance, respectively.  相似文献   
100.
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