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   106篇
  免费   3篇
  国内免费   1篇
林业   6篇
农学   4篇
基础科学   2篇
  14篇
综合类   15篇
农作物   3篇
水产渔业   10篇
畜牧兽医   43篇
园艺   5篇
植物保护   8篇
  2023年   2篇
  2021年   1篇
  2020年   5篇
  2019年   4篇
  2018年   6篇
  2017年   4篇
  2016年   3篇
  2015年   3篇
  2014年   4篇
  2013年   4篇
  2012年   2篇
  2011年   15篇
  2010年   5篇
  2009年   12篇
  2008年   3篇
  2007年   5篇
  2006年   3篇
  2005年   3篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  1999年   3篇
  1997年   1篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   3篇
  1984年   2篇
  1983年   1篇
  1980年   1篇
  1979年   1篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有110条查询结果,搜索用时 15 毫秒
41.
The content and glucosinolate composition of young shoots and raw flower buds of Capparis spinosa var. spinosa and Capparis ovata Desf. var. canescens at three different sizes (x 13 mm) were investigated by HPLC with UV detection. Samples were harvested in August 2001 in Turkey. Twelve different glucosinolates were identified in the young shoots and buds of both species. Total content of glucosinolates ranged from 6.55 micromol/g (large buds of C. spinosa) to 45.56 micromol/g (young shoots of C. ovata). The main glucosinolate was glucocapperin, which amounted to approximately 90% of the total glucosinolates. In both species the total glucosinolate content varied in dependence on the bud size, whereas a greater variability was given for buds from C. spinosa.  相似文献   
42.
Access to information by rural farmers in Nigeria is inefficient due to a variety of factors which include insufficient extension staff and dearth of information in the right format. In order to ensure delivery of timely and relevant information to rural farmers, Information Resource Centers (IRCs) were established in Adopted Villages across the country by the National Agricultural Extension and Research Liaison Services (NAERLS), an agricultural extension research institute based in Ahmadu Bello University, Zaria. Farmers’ access to information was enhanced through this approach and it was cost effective as both NAERLS and the farmers contributed to running the IRCs.  相似文献   
43.
This article described antimicrobial property and structure analysis of 2-hydroxypropane-1,2,3-tricarboxylic acid isolated from the crude extract of Citrus microcarpa. Presently, there was no report on compound from C. microcarpa that possessed antimicrobial property against fish pathogenic bacteria. Therefore, in this study, the bioactive principle in C. microcarpa extract was isolated using thin layer chromatography. It's structure was elucidated based on nuclear magnetic resonance (NMR) spectroscopic data, such as proton NMR (1HNMR), correlation spectroscopy, carbon 13 NMR, and heteronuclear multiple bond correlation data. This study showed that the bioactive compound isolated from C. microcarpa was 2-hydroxypropane-1,2,3-tricarboxylic acid monohydrate. The minimum inhibitory concentration (MIC) values of crude C. microcarpa extract and its bioactive component, 2-hydroxypropane-1,2,3-tricarboxylic acid as well as commercially available synthetic 2-hydroxypropane-1,2,3-tricarboxylic acid, were determined against 18 isolates of Edwardsiella tarda and 7 bacterial reference strains, namely, Escherichia coli (ATCC 25922), Citrobacter freundii (ATCC 8090), Aeromonas hydrophila (ATCC 49140), Pseudomonas aeruginosa (ATCC 35032), Streptococcus agalatiae (ATCC 13813), E. tarda (ATCC 15947), and Yersinia enterocolitica (ATCC 23715), using two-fold microdilution method. The MIC values for both the natural 2-hydroxypropane-1,2,3-tricarboxylic acid and the synthetic one were ranging from 15.6 to 62.5 mg mL-1, whereas that of the crude extract was ranging from 7.8 to 31.3 mg mL-1. These findings showed that both the crude extract and its bioactive component might have potential as antimicrobial agent for aquaculture use.  相似文献   
44.
A cross-sectional epidemiological study was conducted to determine seroprevalence and risk factors influencing the presence of Brucella antibodies in donkeys of Borno State, north-eastern Nigeria. The study aimed at providing baseline information that may be used in planning a control policy against equine brucellosis. Blood samples were collected from 601 donkeys, comprised of 374 males and 227 females from the six agricultural zones of the state between March 2013 and September 2014. The sera obtained were tested for Brucella antibodies using Rose Bengal plate test (RBPT) and competitive enzyme-linked immunosorbent assay (cELISA). Of the 601 donkeys tested, 43 (7.2%) and 40 (6.7%) were seropositive by RBPT and cELISA, respectively. A seroprevalence of 8.6% was obtained in male and 3.5% in female donkeys. According to age, the highest seroprevalence of 9.6% was obtained from donkeys of age group 4–6 years. With respect to pregnancy status, a higher seroprevalence (6.8%) was obtained from pregnant donkeys compared to 3.8% obtained from the non-pregnant ones. There were statistically significant associations between the presence of antibodies and sex (p < 0.05) and the presence of antibodies and age (p < 0.05) of the studied donkeys. However, no statistically significant association (p > 0.05) was observed between the pregnancy status and presence of antibodies. The study concludes that Brucella infection is present in donkeys in all the agricultural zones of the state. The relatively high seroprevalence (7.2%) obtained is of public health concern because of the close interaction between donkeys, ruminants, and humans in the study area.  相似文献   
45.
Antibiogram and heavy metal resistance patterns of pathogenic bacteria isolated from moribund cage cultured silver catfish (Pangasius sutchi) and red hybrid tilapia (Tilapia sp.) from Sungai Manir, Terengganu, Malaysia were studied and characterized. Sungai Manir is one of the famous rivers in Terengganu for its wide variety of cage cultured freshwater fish. However, to date, the baseline information of antibiogram and heavy metal resistance patterns of the pathogenic bacteria attacking the freshwater fish cultured in Sungai Manir is still lacking. Therefore, this study was carried out, which may be useful for fish farmers as a guideline for fish prophylactic and treatment purposes. Furthermore, present studies also provide information on the safety level of consuming freshwater fish produced from Sungai Manir. In the present study, bacteria were isolated from 100 fish of each moribund silver catfish and red hybrid tilapia using seven media including tryptic soy agar (TSA), Mac Conkey, thiosulphate citrate bile salt (TCBS), eosin methylene blue (EMB), glutamate starch pseudomonas (GSP), xylose lysine deoxycholate (XLD) and Baird Parker media. Identification of bacteria was carried out using conventional biochemical tests and confirmed by commercial bacterial identification kit. Antibiogram of the bacterial isolates against 18 antibiotics; oxolinic acid (2 μg), ampicillin (10 μg), erythromycin (15 μg), furazolidone (15 μg), lincomycin (15 μg), oleandomycin (15 μg), amoxicillin (25 μg), colistin sulphate (25 μg), sulphamethoxazole (25 μg), chloramphenicol (30 μg), doxycycline (30 μg), florfenicol (30 μg), flumequine (30 μg), kanamycin (30 μg), nalidixic acid (30 μg), tetracycline (30 μg), nitrofurantoin (50 μg) and spiramycin (100 μg) was carried out using disk diffusion method, whereas heavy metal resistance patterns (Hg2+, Cd2+, Cr6 + and Cu2+) of the bacterial isolates was determined through twofold agar dilution method. The results showed that the percentage of sensitivity case of the 120 bacterial isolates to the tested antibiotics was 62.7%. This was followed by resistance (26.9%) and intermediary sensitive (10.4%) cases. In terms of the heavy metal resistance patterns, all bacterial isolates were resistant to Hg2+ and Cr6 +. However, only 27.8% and 16.7% of the bacterial isolates were sensitive to Cu2+ and Cd2+, respectively. The multiple antibiotic resistance (MAR) indices indicated that the cage cultured silver catfish and red hybrid tilapia were under high exposure to the tested antibiotic. Overall, the results of the present studies showed that Sungai Manir may be polluted with heavy metal and antibiotic residues.  相似文献   
46.
Six healthy camels were treated with the tranquilizers propionyl promazine (Combelen), xylazine (Rompun), acepromazine (Calmivet) or chlorpromazine (Largactil) at single intramuscular doses of 0.5, 0.25, 0.1, or 3 mg/kg, respectively; and the onset, duration and degree of sedation produced by each drug was assessed for six hours. The effect of the treatments on some haematological and biochemical parameters was also studied. The onset and duration of action of the tranquilizers were 10 min and 2.1 +/- 0.5 h for propionyl promazine, 4 min and 3.1 +/- 0.4 h for xylazine, 5 min and 2.3 +/- 0.5 h for acepromazine, 7 min and 2.5 +/- 0.4 h for chlorpromazine, respectively. It was observed that 5-10 min after the administration of the four drugs, camels showed slight irritability, dropping of the lower lips and scratching of the nostrils against objects. During the first hour after medication camels showed frequent urination, defaecation and lacrimation. Xylazine seemed to be superior to the other three drugs in producing sedation. No significant effect on the rectal temperature or the respiratory rates of treated camels was seen after the administration of the four drugs. There were consistent, but statistically insignificant decreases (about 10 p. 100) in the haemoglobin concentration and erythrocyte counts of camels one hour after treatment with the tranquilizers. The four drugs, particularly xylazine and propionyl promazine produced significant hyperglycaemia, but did not alter significantly the plasma concentration of urea or activity of aspartate aminotransferase.  相似文献   
47.
Cawson  Jane G.  Hemming  Victoria  Ackland  Andrew  Anderson  Wendy  Bowman  David  Bradstock  Ross  Brown  Tegan P.  Burton  Jamie  Cary  Geoffrey J.  Duff  Thomas J.  Filkov  Alexander  Furlaud  James M.  Gazzard  Tim  Kilinc  Musa  Nyman  Petter  Peacock  Ross  Ryan  Mike  Sharples  Jason  Sheridan  Gary  Tolhurst  Kevin  Wells  Tim  Zylstra  Phil  Penman  Trent D. 《Landscape Ecology》2020,35(8):1775-1798
Landscape Ecology - Fire behaviour research has largely focused on dry ecosystems that burn frequently, with far less attention on wetter forests. Yet, the impacts of fire in wet forests can be...  相似文献   
48.
Waterlogging is a major constraint of faba bean (Vicia faba L.) production in the highland vertisols of Ethiopia. Genotypes are currently evaluated under both the drained conditions of Broad Bed and Furrow(BBF) and the undrained flatbeds. The objective of this research was to determine if selection of genotypes under BBF is efficient for identification of genotypes for the flatbed conditions. Yields under the flatbed conditions were lower by 20–50% (38% on average) than yields under the BBF. Genetic variation, heritability and predicted genetic gains for grain yield due to direct selection were also lower under the flatbeds than they are under the BBF. There were good levels of genetic correlation (r = 0.20–0.75 or0.45 on average) between yield performances under BBF and flatbeds, indicating that selection under BBF may identify good genotypes for flatbeds and vice versa. There was also high association (r =0.91) between relative yield reduction under flatbeds and the ratio of the predicted genetic gains from indirect selection under BBF to the predicted genetic gains from direct selection under flat beds. This indicates that indirect selection under BBF may be useful to identify better genotypes for flatbed conditions, but the relative efficiency of indirect selection was lower than direct selection under flatbeds themselves. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
49.
The genetic nature of bacterial wilt resistance in tomato was studied in two crosses based on the number of days of survival (quantitative) in the field before the appearance of wilt symptoms. Significant differences were observed between generation means in both crosses (LA 1421 × Cascade and LA 1421 × Caraibo). This study indicates that resistance identified in Lycopersicon esculentum var. cerasiforme LA 1421 may be different from that derived from L. pimpinellifolium. However, the genetic mechanism seems to be complex with a duplicate form of epistasis. Results suggest that selection for resistance from crosses between LA 1421 and Cascade should preferably be delayed until a high level of fixation of genes is attained. The variation observed in the F2 and BC2 progeny of the Caraibo cross, suggested that genetic combination between the two resistance sources can lead to higher levels of resistance. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
50.
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