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191.
During distribution and retail display, fruits and vegetables are often exposed to undesirable temperature and humidity conditions which often result in increased waste due to weight loss and objectionable appearance. Unwaxed fresh-market slicing cucumbers (cv. Calypso) were harvested from a commercial operation and shipped to a distribution center (DC) in Florida. At the DC, 2 d after harvest, cucumbers were sorted and either commercially machine packaged in expanded polystyrene trays covered with a polyvinylchloride film or remained unpackaged for bulk retail display. Cucumbers were transported the next day by truck to a retail store in Gainesville, collected from the store, and stored under optimum (10 °C and 90% RH) or simulated retail display conditions (4 °C or 14 °C and 90–92% RH). Sensory (visual and instrumental color, firmness, shriveling, chilling injury and decay) and compositional quality (pH, titratable acidity, soluble solids and chlorophyll contents) were evaluated initially at the DC and after a 4-d simulated retail display period. Overall, bulk cucumbers were softer, appeared more shriveled, and were more affected by pitting and decay than packaged cucumbers. Bulk cucumbers also appeared lighter green and more yellowish than packaged fruit. Hue angle was less in bulk than in packaged cucumbers, but no consistent differences were observed in the L*, chroma, and hue values between the different temperatures. Small variations in the L*, hue, and chroma values compared to significant losses in chlorophyll content suggest that insufficient chlorophyll degradation occurred to cause major visual color changes. The greater weight loss in bulk cucumbers compared to packaged fruit was associated with accelerated chlorophyll degradation, lower acidity, and lower soluble solids content. Although packaged cucumbers had better visual quality than bulk cucumbers, there was higher RH inside the packages and greater development of decay on packaged fruit. Overall, after the 4-d simulated retail display, the appearance of the cucumbers used in this study was considered to be objectionable due to either yellowing, loss of firmness, shriveling or decay, regardless of the treatment. Results from this study demonstrate the importance of using an appropriate protective package in addition to maintaining the optimum temperature during distribution and retail display. Moreover, initial quality evaluation should be performed upon reception at the DC, and before cucumbers are displayed at the retail store, in order to estimate the remaining shelf life before this product becomes unacceptable for sale.  相似文献   
192.
Conventional methods used in laboratory animals for collection of resident macrophages (MAC) proved suitable for isolation of hepatic, splenic, dermic, peritoneal and alveolar MAC of healthy dogs. Phagocytic assays of IgG opsonised SRBC were performed with resident MAC obtained from these organs. Results showed the existence of statistically significant differences among phagocytic capacity of the investigated MAC. According to this, three groups of MAC could be defined: a first group comprising dermic, splenic and alveolar MAC; a second group comprising hepatic MAC and a third group comprising peritoneal MAC.  相似文献   
193.
The structure of the corneas of adult and young reindeer, roedeer and elk was studied. The corneas were strikingly similar in general appearance. The number of squamous cells was found to be the main difference. The thickness of the cornea and that of the membrane of Descemet was found to be greater in older animals.  相似文献   
194.
Hydrocolloid interaction with water, protein, and starch in wheat dough   总被引:1,自引:0,他引:1  
Interaction of hydrocolloids (xanthan gum, locust bean gum, guar gum, and high-methoxyl pectin) with macrocomponents of dough (water, starch, and protein) was evaluated by different techniques. (1)H spin-spin NMR relaxation assays were applied to study the mobility of the gluten-hydrocolloid-water matrix, and the amount of freezable water was determined by differential scanning calorimetry (DSC). Starch gelatinization parameters (T, enthalpy) were also analyzed by DSC. The influence of additives on the protein matrix was studied by Fourier transform (FT) Raman assays; analysis of the extracted gliadins and glutenins was performed by electrophoresis (SDS-PAGE). A significantly higher molecular mobility was found in matrices containing xanthan gum, whereas pectin led to the lowest molecular mobility. Freezable water showed a trend of increasing in the presence of hydrocolloids, particularly under conditions of water restriction. Starch gelatinization final temperature was decreased when hydrocolloids were added in the presence of enough water. In general, FT-Raman and SDS-PAGE indicated that hydrocolloid addition promoted a more disordered and labile network, particularly in the case of pectin addition. On the other hand, results obtained for dough with guar gum would indicate a good compatibility between this hydrocolloid and the gluten network.  相似文献   
195.
Chusquea ramosissima is a native monocarpic bamboo species growing in subtropical forests of northeastern Argentina, which can dominate gaps and open forests in the region, particularly after human disturbance. This bamboo species started to flower in different areas of northeastern Argentina in 2001, with the flowering peak during 2002 and 2003 and small isolated flowering events still occurring until 2010. We studied the effects of C. ramosissima flowering and die-back on microclimate, litter decomposition, nutrient availability, sapling growth, abundance and regeneration of tree canopy species. We wanted to know how environmental conditions and ecosystem processes change through time after bamboo flowering and if bamboo die-back would favor regeneration of canopy trees. Twenty 50 × 50 m plots of flowering and non-flowering bamboo were permanently marked and vegetation dynamics as well as nutrient cycling and microclimate studies were performed. C. ramosissima die-back enhanced growth and reduced mortality rate of tree saplings during the first year after flowering. Only growth of tree saplings previously established was enhanced by the flowering event and tree-species richness and saplings abundance of canopy trees did not change as expected due to bamboo flowering. The short-term effect of tree saplings growth was likely due to incident solar radiation at the forest floor which doubled in the first year after the bamboo flowering event. Increased light availability at the forest floor simultaneously promoted the growth of other understory plants such as ferns, lianas and Piper spp. that rapidly colonized gaps and intercepted a percentage of the incident solar radiation after the first year, which together with an increased litter layer due to the senescence of the bamboo, may have inhibited establishment of new tree individuals and affected tree growth. Contrary to predictions, soil water, litter decomposition and soil nutrients were not significantly affected by bamboo flowering. Thus, successful tree regeneration in gaps following bamboo flowering appears to be restricted to a very narrow window of increased light availability (i.e., 1 year) before growth of other understory plants and rapid re-colonization of bamboo. Changes in resource availability, and the opportunity for overstory regeneration after bamboo flowering events appears to depend on climatic and community characteristics of the ecosystem where the flowering event occurs and also, on the flowering patterns and their synchronicity.  相似文献   
196.
Peel damage originated by wind is the main abiotic cause of citrus fruit discards for export in Uruguay. Natural windbreaks such as Eucalyptus and Casuarinas have not been effective in reducing it. This research was carried out during three years in a citrus orchard situated in the coastal plain of Uruguay (35° SL). The purpose of this work was to study wind climate inside the orchard, fruit seasonal sensitivity, basal leaf effect on the onset and evolution of peel damage, and the efficiency of artificial windbreaks to reduce fruit discard of ‘Ellendale’ tangor. Average wind velocity in the orchard did not exceed 5 m s−1. First peel scars were evident two weeks after petal fall and damaged fruit percentage importantly increased during the first stage of fruit growth. Low energy vortexes caused almost permanent friction between basal leaves and the developing fruitlets growing in their axil. Removal of the basal leaf decreased significantly wind damaged fruit. Natural wind flow modification through the use of semi-porous artificial windbreak nets (5 cm by 10 cm mesh) modified low energy vortexes and increased significantly the percentage of export quality fruit. We conclude that this type of net is more efficient than natural windbreaks or classical nets to reduce wind damage in citrus fruit.  相似文献   
197.
The utilization of phosphites (Phi) could be considered as another strategy to be included in integrated disease management programmes to reduce the intensive use of fungicides and production costs. The aim of the present work was to analyze whether the beneficial effects of phosphite treatment previously observed in potato plants grown under greenhouse conditions, were reflected after harvest of field grown potatoes, both in disease protection and in yield. In addition, biochemical compounds possibly involved in induced defence responses by Phi, like phytoalexins, pathogenesis related proteins and oxidative stress enzymes were measured. Foliar applications of KPhi to field grown crops resulted in post-harvest tubers with a reduced susceptibility to Phytophthora infestans, Fusarium solani and Erwinia carotovora infections, suggesting that this compound induced a systemic defence response. An increase in phytoalexin content in P. infestans inoculated tubers obtained from Phi-treated plants suggests their participation in the defence response. Chitinase content increased 72 h after wounding or inoculation with P. infestans in tubers from KPhi-treated plants compared to wounded or infected tubers from non-treated plants. Contrary to this, the isoforms of β-1,3-glucanases analyzed did not increase in the tubers of Phi-treated plants. The increment in peroxidase and polyphenol oxidase activities indicated that these enzymes could be part of the Phi defence mechanism. No negative effects were observed in potato yield at harvest, measured as total tuber weight and dry matter, after foliar KPhi treatment. This suggests that the energetic cost involved in the defence response activation would not be detrimental to plant growth.  相似文献   
198.
The objective was to quantify the effect of furosemide and carbazochrome on exercise-induced pulmonary hemorrhage (EIPH) in Standardbred horses using red blood cell count and hemoglobin concentration in bronchoalveolar lavage (BAL) fluid. Six healthy Standardbred horses with prior evidence of EIPH performed a standardized treadmill test 4 h after administration of placebo, furosemide, or furosemide–carbazochrome combination. Red blood cell (RBC) counts and hemoglobin concentrations were determined on the BAL fluid. The RBC count in BAL ranges were (2903–26 025 cells/μL), (45–24 060 cells/μL), and (905–3045 cells/μL) for placebo, furosemide, and furosemide–carbazochrome, respectively. Hemoglobin concentration ranges were (0.03–0.59 mg/mL), (0.01–0.55 mg/mL), and (0.007–0.16 mg/mL) for placebo, furosemide, and furosemide– carbazochrome groups, respectively. No significant differences were detected among treatments. However, there was great variability among horses, suggesting that a larger sample size or better selection of horses was needed.  相似文献   
199.
Spider plant exists as semi-cultivated indigenous leafy vegetable with ecological, social and cultural values in most home gardens in Kenya. It plays a significant role in the food and nutrition security of local communities. The tender leaves are usually consumed as a cooked vegetable while the roots, stem and whole leaves are used for medicinal purposes. The importance of spider plant has been discussed in the context of biodiversity conservation and food security because the vegetable is rich in micronutrients and phytochemicals associated with antioxidant, anti-malaria, and anti-microbial properties.  相似文献   
200.
Downy mildew (DM), caused by the fungus Peronospora parasitica, is a destructive disease of radish (Raphanus sativus L.) worldwide. Host resistance has been considered as an attractive and environmentally friendly approach to control the disease. However, the genetic mechanisms of resistance in radish to the pathogen remain unknown. To determine the inheritance of resistance to DM, F1, F2 and BC1F1 populations derived from reciprocal crosses between a resistant line NAU-dhp08 and a susceptible line NAU-qtbjq-06 were evaluated for their responses to DM at seedling stage. All F1 hybrid plants showed high resistance to DM and maternal effect was not detected. The segregation for resistant to susceptible individuals statistically iftted a 3:1 ratio in two F2 populations (F2(SR) and F2(RS)), and 1:1 ratio in two BC1F1 populations, indicating that resistance to DM at seedling stage in radish was controlled by a single dominant locus designated as RsDmR. A total of 1 972 primer pairs (1 036 SRAP, 628 RAPD, 126 RGA, 110 EST-SSR and 72 ISSR) were screened, and 36 were polymorphic between the resistant and susceptible bulks, and consequently used for genotyping individuals in the F2 population. Three markers (Em9/ga24370, NAUISSR826700 and Me7/em10400) linked to the RsDmR locus within a 10.0 cM distance were identiifed using bulked segregant analysis (BSA). The SRAP marker Em9/ga24370 was the most tightly linked one with a distance of 2.3 cM to RsDmR. These markers tightly linked to the RsDmR locus would facilitate marker-assisted selection and resistance gene pyramiding in radish breeding programs.  相似文献   
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