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   68篇
  免费   4篇
林业   6篇
农学   1篇
基础科学   1篇
  9篇
综合类   3篇
农作物   5篇
水产渔业   6篇
畜牧兽医   20篇
园艺   11篇
植物保护   10篇
  2023年   2篇
  2022年   4篇
  2021年   2篇
  2019年   5篇
  2018年   7篇
  2017年   3篇
  2016年   5篇
  2015年   2篇
  2014年   2篇
  2013年   2篇
  2012年   3篇
  2011年   6篇
  2010年   6篇
  2009年   4篇
  2008年   2篇
  2007年   2篇
  2006年   4篇
  2005年   7篇
  2004年   2篇
  2002年   1篇
  1996年   1篇
排序方式: 共有72条查询结果,搜索用时 62 毫秒
1.
An outbreak ofDichelia cedricola (Diakonoff) (Lep.: Tortricidae), the cedar shoot moth (CSM), began in spring 1998 and lasted 3 years. This was the first monitored outbreak of the CSM in Isparta, Turkey. Tree crowns recovered to near normal condition by the middle of each growing season (in early June) during the outbreak. Tree volume and volume element increments were examined throughout the outbreak cycle from 1954 to 2001. In the past, CSM activity in stands of Lebanon cedar (Cedrus libani A. Rich.) was assessed through radial increment analyses. Cedar tree ring chronologies were analyzed for evidence of the CSM. Tree-ring chronologies from nonhost cedar (nondefoliated sample trees) were used to estimate potential growth in the host cedar (defoliated sample trees) during current and past outbreaks; all trees selected were the same subspecies and varieties. Regional outbreaks of the CSM were identified by synchronous and sustained growth periods of the trees. In 2001, increment cores were collected from 17 host and 16 nonhost dominant or codominant trees and annual radial growth indices from 1954–2001 were calculated for each of two host and two nonhost sample plots. Growth functions were defined as the cumulative sum of radial, height, and volume increment, and were graphically compared between CSM host cedar and nonhost cedar trees. Tree ring evidence suggests that a large-scale outbreak occurred in 1955 (from 1955 to 1966) and a small outbreak occurred in 1985 (1985–1990) and in 1998 (1998-continued) in the study area. The average diameter growth reductions around 1955, 1985 and 1998 were 40%, 46% and 7% of potential, respectively. It was concluded that a narrow latewood band is significant indicator of defoliation by the CSM and the outbreaks appear to be associated with dry winter and spring weather prior to the autumn and winter in which wood feeding occurred. http://www.phytoparasitica.org posting Nov. 24, 2004.  相似文献   
2.
Accelerated soil salinization is a worldwide concern. Our study was carried out to determine the effects of different rates (0, 5, 10, and 15?mmol kg?1) of iron (III) ferrocyanide application to remove salts from the soil. Within two weeks of its application, iron (III) ferrocyanide at 5, 10, and 15?mmol?kg?1 removed 12.2%, 26.5%, and 42.9% of the total salts from the soil, respectively. Results suggested that iron (III) ferrocyanide application at 15?mmol?kg?1 is one of the most rapid and effective ways to remove substantial amounts of salts from undrained soil (land) where fresh water is scarce.  相似文献   
3.
ABSTRACT:   The effects of the different catching methods (gillnet, longline, harpoon) on sensory, chemical (pH, total volatile base nitrogen, K -value) and microbiological (total viable count [TVC]) changes in pike perch Sander lucioperca stored in ice were investigated. The same soaking time was used for both gillnet and longline fishing. The catching method had considerable influence on the freshness quality of pike perch. The acceptable shelf life was 15 days for pike perch caught by gillnet, and 22 days for longline and harpoon. The initial concentrations of inosine monophosphate (2.4 μmol/g) in pike perch caught by gillnet were significantly lower ( P  < 0.05) than longline (4.1 μmol/g), and especially by harpoon (16.7 μmol/g). However, the initial K -values for fish caught by harpoon were significantly ( P  < 0.05) lower (24.36%) than fish caught by longline and gillnet (57.69%, 64.41%, respectively). The average K , Ki, G and H -values at rejection day in terms of sensory assessment were approximately 90, 98, 156 and 40%, respectively, for all catching methods during ice storage. However, TVC reached 7.0 log cfu/g after approximately 11 days of storage for fish caught by gillnet, 19 days for fish caught by longline and 8 days for fish caught by harpoon. The result of this study suggests that the best catching method for preserving the freshness of pike perch is longline, based on the data obtained from the sensory and microbiological analysis.  相似文献   
4.
5.
6.
Fig has been a typical fruit component of the health-promoting Mediterranean diet for a very long time. Phytochemical characters and antioxidant capacity of green-, yellow-, brown-, purple-, and black-fruited fig (Ficus carica L.) accessions were investigated. In this study, total phenolics (TP), total anthocyanins (TA), fructose (FRUC), glucose (GLUC), sucrose (SUC), and variables (such as L*, a*, C*, and hue°) describing fruit skin colors were examined. Also, the antioxidant capacity (TAC) of fig fruits was determined by the ferric reducing antioxidant power (FRAP) assay. Antioxidant capacity was significantly correlated with the polyphenol and anthocyanin (r = 0.74 and 0.63, respectively) contents of fruits. Black fig accessions had the highest TAC (range of 7.9–16.1, mean 12.4 Fe2+ mmol/kg FW), TA (range of 32.3–356.0, mean 128.4 μg cy-3-rutinoside/g FW), and TP content (range of 69.1–220.0, mean 118.9 mg GAE/100 g FW). These black-fruited accessions had 2-fold greater TAC, 15-fold greater TA, and 2.5-fold greater TP than green and yellow fig accessions. However, the FRUC, GLUC, and SUC content of brown and purple fig accessions were higher than those of other color groups. The predominant sugars present were fructose (∼56%) and glucose (∼43%), as determined by HPLC.  相似文献   
7.
1.?The study was conducted to determine the effects of dietary supplementation of enzyme and oregano essential oil at two levels, alone or together, on performance, digestive enzyme, nutrient digestibility, lipid metabolism and immune response of broilers fed on wheat–soybean meal based diets.

2.?The following dietary treatments were used from d 0 to 21. Diet 1 (control, CONT): a commercial diet containing no enzyme or oregano essential oil, diet 2 (ENZY): supplemented with enzyme, diet 3 (EO250): supplemented with essential oil at 250 mg/kg feed, diet 4 (EO500): supplemented with essential oil at 500 mg/kg feed, diet 5 (ENZY + EO250): supplemented with enzyme and essential oil at 250 mg/kg, and diet 6 (ENZY + EO500): supplemented with enzyme and essential oil at 500 mg/kg.

3.?Birds fed on diets containing ENZY, EO250 and ENZY + EO250 had significantly higher weight gain than those given CONT diet from d 0 to 7. No significant effects on feed intake, feed conversion ratio, mortality, organ weights except for jejunum weight and intestinal lengths was found with either enzyme or essential oil, alone or in combination, over the 21-d growth period. The supplementation of essential oil together with enzyme decreased jejunum weight compared with essential oil alone.

4.?Supplementation with enzyme significantly decreased viscosity and increased dry matter of digesta, but did not alter pH of digesta. There was no effect of essential oil alone at either concentration on viscosity, dry matter or pH of digesta. A significant decrease in viscosity of digesta appeared when essential oil was used with together enzyme.

5.?The supplementation of essential oil at both levels with or without enzyme significantly increased chymotrypsin activity in the digestive system, and improved crude protein digestibility.

6.?The higher concentration of essential oil with and without enzyme significantly increased serum total cholesterol concentrations. No significant effect on immune response was found with either enzyme or essential oil, alone or together.

7.?Enzymes and essential oil had different modes of actions. The supplementation of enzyme with essential oil in diets is likely more effective in view of performance, nutrient digestibility, enzyme activities and immune system.  相似文献   

8.
Several methods for measuring sulfite oxidases (EC 1.8.2.1 and EC 1.8.3.1) have been developed for microbial systems, but none have been systematically adopted for soils. We describe an assay method to measure sulfite oxidase in soil that is based on the use of potassium sulfite (K2SO3) serving as the substrate and electron donor, and potassium ferricyanide [K3Fe(CN6)] serving as the electron acceptor. Sulfite oxidase activity is expressed as micromoles of K3Fe(CN)6 reduced g-1 soil 4 h-1. Sulfite oxidase activity was linearly related to amount of soil in the assay (up to 3 g) and incubation time (up to 5 h). The average K m value for K2SO3 serving as the substrate for the sulfite oxidase reaction in four diverse soils was 3.48 mM. The activation energy values calculated for soil sulfite oxidase ranged from 40.4 to 61.4 kJ mol-1. The sulfite oxidase assay does not require any specialized equipment and is expected to be useful in studying biological sulfite oxidation in soils treated with sulfites or in naturally occurring soils where sulfur cycles between reduced (i.e., sulfite) and oxidized (i.e., sulfate) states due to flooding and drying.  相似文献   
9.
An outbreak of the pine processionary moth (PPM), Thaumetopoea wilkinsoni Tams (Lepidoptera: Thaumetopoeidae), began in spring 1998 and lasted 6 years in a Crimean pine (Pinus nigra Arnold) plantation in western Turkey. The effects of PPM on the radial, height and volume growth of Crimean pine trees were investigated by examining the increment losses for three defoliation intensities (groups). PPM activity in Crimean pine stand was assessed through radial increment analysis of cores extracted at breast height. In 2004, increment cores were collected from moderate and high defoliation and low defoliation dominant or co-dominant trees. Based on the sample, annual radial growth indices from 1998 to 2004 were calculated. Growth functions were defined as the cumulative sum of radial, height and volume increment graphically compared between Crimean pine defoliation group sample trees. The sample trees are the same subspecies and varieties. After the defoliations, radial, height and volume growth of low defoliation group trees was found to be significantly greater than that of the other affected groups. During the 1998–2004 period the total radial growth of low, moderately affected and highly affected trees was, respectively, 49, 33 and 31 mm; the total height growth was 3.1, 1.8 and 1.0 m; and the total volume growth was 50, 14 and 10 dm3.  相似文献   
10.
Fusarium oxysporum f. sp. lycopersici (FOL) races and F. oxysporum f. sp. radicis lycopersici (FORL), the causal agents of root rot and crown rot diseases, respectively, cause serious economic losses in tomato greenhouses where production is intensive in the West Mediterranean region of Turkey. The isolates were collected from West Mediterranean region of Turkey and were characterized by specific primers based on three races (r1, r2, r3), besides pathogenicity tests in in vivo conditions Additionally, a scheme was developed using newly tested ISSR and SRAP markers to a genotyping database and to determine the possible origin of these pathogens. The present study provided new information on these pathogens based on their races and their dominant existence in this region that has not been reported before. Genetic diversity detected in the same races of the pathogen may be associated with difficulties in controlling the pathogen and a possible resistance formation effort exerted by the pathogen to chemicals used in plant protection in tomato greenhouses. Molecular analyses indicated genetic diversity in pathogen isolates identified as r3, r2 and FORL, which may be associated with abiotic stress to which the pathogens were exposed.  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