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   94篇
  免费   3篇
农学   2篇
基础科学   2篇
  20篇
综合类   5篇
农作物   5篇
水产渔业   19篇
畜牧兽医   27篇
园艺   11篇
植物保护   6篇
  2022年   2篇
  2021年   1篇
  2020年   3篇
  2019年   1篇
  2018年   4篇
  2017年   1篇
  2016年   6篇
  2015年   5篇
  2014年   3篇
  2013年   11篇
  2012年   6篇
  2011年   9篇
  2010年   5篇
  2009年   7篇
  2008年   6篇
  2007年   6篇
  2006年   3篇
  2005年   3篇
  2004年   1篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  2000年   2篇
  1998年   1篇
  1994年   1篇
  1985年   1篇
排序方式: 共有97条查询结果,搜索用时 15 毫秒
81.
Determination of temporal and spatial distribution of water use (WU) within agricultural land is critical for irrigation management and could be achieved by remotely sensed data. The aim of this study was to estimate WU of dwarf green beans under excessive and limited irrigation water application conditions through indicators based on remotely sensed data. For this purpose, field experiments were conducted comprising of six different irrigation water levels. Soil water content, climatic parameters, canopy temperature and spectral reflectance were all monitored. Reference evapotranspiration (ET0), crop coefficient Kc and potential crop evapotraspiration (ETc) were calculated by means of methods described in FAO-56. In addition, WU values were determined by using soil water balance residual and various indexes were calculated. Water use fraction (WUF), which represents both excessive and limited irrigation applications, was defined through WU, ET0 and Kc. Based on the relationships between WUF and remotely sensed indexes, WU of each irrigation treatments were then estimated. According to comparisons between estimated and measured WU, in general crop water stress index (CWSI) can be offered for monitoring of irrigated land. At the same time, under water stress, correlation between measured WU and estimated WU based on CWSI was the highest too. However, canopy-air temperature difference (Tc − Ta) is more reliable than others for excessive water use conditions. Where there is no data related to canopy temperature, some of spectral vegetation indexes could be preferable in the estimation of WU.  相似文献   
82.
Frass is the by‐product of the larval meal industry and includes larval waste, exoskeleton sheds and residual feed ingredients. Experimental frass was derived from the larvae of black solder flies fed distillers' dried grains with solubles and had a protein and fat content of 216 and 60 g/kg, respectively. A 10‐week study was conducted to evaluate the effect of dietary levels of frass on growth, feed utilization, and body proximate and mineral composition of channel catfish, Ictalurus punctatus. Five diets containing 0, 50, 100, 200 and 300 g frass per kg diet were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. Final weight gain was significantly increased in fish fed diets containing frass at levels from 100 to 300 g/kg. Fish fed diets without frass, and with 300 g/kg frass, showed the lowest and highest feed intake, respectively. Feed and protein efficiencies, however, were significantly lower in fish fed frass at levels of 200 g/kg and higher compared to the control diet. Survival, whole‐body composition and mineral content were not affected by frass. In summary, black soldier fly larval frass has potential as a protein source or just an ingredient for enhancing palatability of catfish diets.  相似文献   
83.
Wheat production is a major source of income for most people and forms the backbone of the economy in Central Anatolia, Turkey. Sunn pest, known in Turkey since 1927, is one of the most harmful pests of wheat in this region where the infested area has reached 0.3 million ha and the cost of chemical application has reached US$ 2 million per year. Two species of Eurygaster, E. maura and E. austriaca, are prevalent in the region. Observations of tests carried out on different genotypes under natural field conditions and controlled greenhouse tests showed variable response of wheat to sunn pest. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
84.
In order to study the effect of brassinosteroids on the amelioration of the inhibitory effect of salinity on strawberry plants, a short-term experiment was conducted in greenhouse to test different concentrations of 24-epibrassinolide (24-EBL) (0.0, 0.5, and 1 μM) by foliar application on some agro-physiological properties, such as shoot dry weight, and root dry weight, stomatal conductance (SC), leaf relative water content (LRWC), leaf chlorophyll reading values (LCRV) and membrane permeability (MP) of strawberry ‘Fern’ and ‘A6’ cultivars irrigated with salt water (35 mM NaCl). 24-EBL solutions were applied twice during late afternoon hours with 7 d intervals using a hand-held sprayer. Plant shoot dry weight, root dry weight, SC, LRWC and LCRV were reduced by 29–33%, 45–15%, 71–55%, 11–13%, and 12–13% for ‘A6’ and ‘Fern’ cultivars at 35 mM (without 24-EBL applied), respectively, as compared to the nonsaline treatment, but MP increased 40% and 12%. An exogenous supply of 24-EBL was found to be successful in alleviating of the inhibitory effects of salt stress on plant growth parameters and nutrient contents. 24-EBL (1 μM) application under saline condition significantly increased shoot and root dry matter, SC, LRWC and LCRV of plants, and alleviation effects of 1 μM 24-EBL application was 20%, 15%, 122%, 5.8%, and 10.9% for ‘A6’ and 47%, 8.0%, 83%, 33.3% and 6.0% for ‘Fern’ cultivars, respectively. Macro-micro element content of plant leaf and root increased with increase 24-EBL except for Na under salinity stress. These results support the view that supplementary 24-EBL application can overcome the effects of salinity stress on plant growth and growth parameter under saline conditions.  相似文献   
85.
This study was conducted to evaluate the roles of glycine betaine (GB) in mitigating deleterious effect of salt stress on lettuce. Lettuce plants were subjected to two salinity (0 and 100 mmol l?1 NaCl) and four GB levels (0, 5, 10, 25 mmol l?1). Salinity resulted in a remarkable decrease in growth parameters, relative leaf water content and stomatal conductance. Plants subjected to salt stress exhibited an increase in membrane permeability (MP), lipid peroxidation (MDA), leaf chlorophyll reading value, H2O2 and sugar content. Exogenous foliar applications of GB reduced MP, MDA and H2O2 content in salt-stressed lettuce plants. Salt stress increased Na and generally decreased other nutrient elements. GB reduced Na accumulation, but significantly increased other element contents under salinity conditions. The study showed that gibberellic acid (GA) and salicylic acid (SA) content in salt-stressed plants were lower than those of nonstressed plants. However, salinity conditions generally increased the abscisic acid content. GB treatments elevated the concentrations of GA, SA and indole acetic acid (IAA) at especially 10 and 25 mmol l?1 GB under salt stress conditions. It could be concluded that exogenous GB applications could ameliorate the harmful effects of salt stress in lettuce.  相似文献   
86.
The aim of this study was to evaluate the effect of plant growth promoting bacteria (PGPB) on emergence, growth, physiology, and mineral content of radish under salinity stress. The study was conducted in pot experiments using a mixture of soil: sand (1:1 v: v) under greenhouse conditions. Bacillus subtilis EY2, Bacillus atrophaeus EY6, and Bacillus spharicus GC subgrup B EY30 were isolated in highly salty soils in Upper Coruh Valley in Turkey. Seeds were soaked in the bacterial suspension incubated at 27°C for 2 h. Emergence percentage (EP) was reduced and mean emergence time (MET) raised with sodium chloride (NaCl) solutions. Inoculated seeds displayed greater EP and less MET compared to the non-inoculated ones. Salinity negatively affected growth of radish; however, plant growth promoting bacteria treatments positively affected growth parameters such as fresh weight (278% for shoot, 371% for root) and dry weights (250% for shoot, 422% for root) compared to non-treated plants that were challenged with salt stress. Furthermore, selected bacteria caused an increase in uptake of minerals except sodium (Na) compared to the non-treated controls in both salt stress and salt stress absence. Sodium concentration of plant leaves was increased by salt stress while bacterial inoculation decreased its concentration. Bacterial treatments increased chlorophyll content and decreased electrolyte leakage of plants in saline conditions. Leaf relative water content (LRWC) of plants in the salt stress condition increased with bacterial application, but reduced without bacterial application. The present study suggests that PGPB seed treatments can ameliorate the deleterious effects of salt stress on radish plants and PGPB could offer an economical and simple application to reduce problems of radish production in an Aridisol caused by high salinity.  相似文献   
87.
The aim of this study is to characterize 10 European chestnut (Castanea sativa Mill.) accessions which were selected among 80 accessions at the end of a selection study in Nazilli in Turkey. During the harvest periods in 2001, 2002 and 2003, European chestnut accessions were examined. Nineteen morphological, pomological and biochemical characters were used. Significant genotype×year interaction were found for all traits but one. Multivariate methods, including cluster and principal component analysis were performed to characterize the accessions. The first five principal components account for 86.44% of the total variance of all traits, indicating a high degree of correlation among the characteristics analyzed. High level of phenotypic proximity was found between the accessions N-20-2 and N-5-1 based on pomological, morphological and biochemical characteristics.  相似文献   
88.
The predatory insect Anthocoris minki Dohrn (Heteroptera: Anthocoridae) is an indigenous Anthocoris species for the biological control of pests in pistachio orchards. The pistachio psylla Agonoscena pistaciae Burckhardt and Lauterer (Homoptera: Psyllidae) is an important insect pest in pistachio trees in Turkey. Similarly, Brachycaudus (Thuleaphis) amygdalinus (Schouteden) (Hemiptera: Aphididae) is a pest of almond trees that is considered as alternative prey for A. minki when pistachio psylla are not available in early spring on pistachio trees. The development time, survival percentage of immature stages, longevity, fecundity, prey consumption, and life table parameters of A. minki fed on A. pistaciae and B. amygdalinus nymphs were determined at 25 ± 1°C, 70 ± 5% r.h., and a 16 h:8 h (L:D) photoperiod under laboratory conditions. The nymphal survival rate was significantly higher when nymphs were fed on A. pistaciae (an average of 96.7%) than on B. amygdalinus (an average of 71.4%). The development time of A. minki was significantly shorter when nymphs were fed on B. amygdalinus (10.3 days) as opposed to A. pistaciae (11.0 days). No significant differences among prey species were found for longevity and fecundity. The total female longevity and fecundity of A. minki was 38.0 days and 247.2 eggs, respectively, when nymphs were fed on A. pistaciae; and 35.4 days and 233.0 eggs, respectively, when nymphs were fed on B. amygdalinus. On average, 104.4 A. pistaciae and 77.7 B. amygdalinus nymphs were consumed during the nymphal development time for A. minki. Adults of A. minki consumed significantly more psyllids than aphids throughout their life span. The greater difference did not significantly inpact the longevity and fecundity of A. minki. Females of A. minki consumed an average of 631.0 A. pistaciae and an average of 273.3 B. amygdalinus nymphs, while female predators consumed significantly more prey than males. The intrinsic rate of increase (r m ) of A. minki fed on A. pistaciae (0.174) was significantly greater than those fed on B. amygdalinus (0.148). The successful development and reproduction of both A. pistaciae and B. amygdalinus indicates that they are suitable prey for A. minki.  相似文献   
89.

Background

Rapid determination of blood electrolyte concentrations can help determine electrolyte status and delivery of effective volume of electrolyte solutions in field conditions.

Objective

To evaluate reliability of the i‐STAT, a point‐of‐care (POC) device, in measuring blood K+, Na+, and CI concentrations in cattle.

Animals

Ninety‐eight cattle with various diseases.

Methods

In this prospective study, blood samples collected from the jugular vein were processed for determination of K+, Na+, and CI concentrations in blood and plasma using the i‐STAT and auto‐analyzer (Cobas C501), respectively. Blood and plasma electrolyte data were subjected to student t‐test for comparison, the concordance analysis for agreement, accuracy, and precision, the Passing‐Bablok regression and the Bland‐Altman plot for reliability, and receiver operating characteristics curves for sensitivity (Se) and specificity (Sp).

Results

Plasma concentrations of K+ (4.39 versus 4.2 mmol/L; < .0001) and CI (100.30 versus 99.4 mmol/L; < .04) were greater than their concentrations in blood. Plasma and blood Na+ concentrations were similar (136.95 versus 136.8 mmol/L). The i‐STAT results were highly correlated with the Cobas C501 results (= 0.970, 0.922, and 0.866 for K+, Na+, and CI , respectively). Regression equations fitting blood (Y) and plasma (X) concentration did not deviate from the identity line for K+ (Y = −0.10 + 0.98 × X), Na+ (Y = X), and CI (Y = 3.04 + 0.96 × X). The mean bias (blood concentration ‐ plasma concentration) was −0.20 for K+ (= .03), −0.16 for Na+ (= .12), and −0.87 for CI (= .93). The i‐STAT had 76–100% Se and 87.7–100% Sp for assessing electrolyte statuses.

Conclusions and Clinical Importance

The i‐STAT yielded results that were in agreement with the auto‐analyzer, with negligible biases in measurement of plasma K+, Na+, and CI concentrations. The i‐STAT is a reliable POC device and can be used in field condition to assess electrolyte status in cattle.  相似文献   
90.
In this study, genetic analysis of Triticum spp. was carried out using AFLP markers. Six AFLP selective combinations were scored as presence and absence of bands for all the individual samples obtained from a single seed of each accession (70 accessions); T. baeoticum (21), T. monococcum (5), T. urartu (16), T. araraticum (7), T. dicoccoides (16) and T. dicoccon (5), resulting in 506 polymorphic AFLP bands. The phylogenetic tree showed two major clusters; one was composed of T. monococcum (AA) and T. baeoticum (AA), and the other cluster included T. araraticum (AAGG), T. dicoccon (AABB), T. dicoccoides (AABB), and T. urartu (AA). T. urartu, although having a diploid AA genome, did not cluster with other A genome diploids such as T. monococcum and T. baeoticum; instead it clustered together with the tetraploid species, confirming that T. urartu is the A genome progenitor. The extent of variations within and among species is discussed.  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