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61.
Abstract

Dissolved gas supersaturation is hazardous to fish and can result in gas bubble disease (GBD). Signs of GBD typically include bubbles in the eyes, fins, skin, lateral line, and gill filaments. Ocular abnormalities in diseased salmonids typically occur after aberrant gas production in the eyes. In this study, freshwater rainbow trout Oncorhynchus mykiss were exposed experimentally to percent total gas pressure (TGP%) levels of 104% (control) and 115%. No mortalities occurred during the 7-d experimental period. Effects of GBD were observed externally as a darkened skin, exophthalmia, localized hemorrhage in the eye, and gas bubbles on the operculum. Additional signs included increased swimming activity and, more frequently, panic episodes. Carbonic anhydrase (CA) enzyme activities from the lens and retina were determined at days 0, 1, 3, 5, and 7 of the study. Venous blood gases were also measured on day 7. Retinal pH did not differ between normal and affected fish, but blood characteristics such as the partial pressure of O2, partial pressure of CO2, carboxyhemoglobin level, and bicarbonate ion concentration were significantly elevated in affected fish relative to normal fish. Venous blood pH and oxyhemoglobin levels were not significantly different between affected and normal fish. Patterns of response to total dissolved gas levels differed between the lens and the retina. Mean CA activities in the lenses of fish exposed to a TGP% level of 115% were significantly below those of control fish. However, retinal CA activities did not significantly differ between the two groups over the course of the experiment. These findings show that dissolved gas supersaturation reduces CA activity in the rainbow trout lens.

Received June 17, 2010; accepted March 20, 2011  相似文献   
62.
1. The aim of the study was to describe the effect of Epigallocatechin-3-gallate (EGCG), a polyphenol derived from green tea, on activator protein-1 (AP-1) components (phospho-c-Jun and c-Fos), cyclooxygenase-2 (COX-2) and heat shock proteins (HSPs) in the liver of heat-stressed quails.

2. A total of 180 5-week-old female Japanese quails were reared either at 22°C for 24 h/d (thermoneutral, TN) or 34°C for 8 h/d (heat stress, HS) for 12 weeks. Birds in both environments were randomly given 1 of 3 diets: basal diet and basal diet with 200 or 400 mg of EGCG added per kilogram of diet.

3. The hepatic c-Jun, c-Fos, COX-2 and HSPs gene expression for quails reared under the HS environment was greater than those reared under the TN environment. Supplemental EGCG decreased hepatic expression of these proteins at a greater extent under HS than TN.

4. In conclusion, suppression of AP-1 COX-2 and HSPs may partly account for the inhibitory effect of EGCG in heat-stressed quail.  相似文献   

63.
The diversity of pale flax (Linum bienne Mill.) as the progenitor of cultivated flax (L. usitatissimum L.) has not been well documented and the domestication syndromes in cultivated flax are poorly understood. An attempt was made to characterize 34 pale flax accessions and six cultivated flax accessions collected during 2007 summer in Turkey. A total of 12 quantitative and 7 qualitative characters covering vegetative and generative plant parts, including phenological traits, were assessed. The occurrence of yellow anthers well known in cultivated flax is reported for the first time in pale flax. Pale flax displayed larger variation in vegetative plant parts and growth habit than the cultivated flax and more heterogeneity within accessions. Within pale flax, a higher degree of variation was observed in many generative parts such as the flower characters than in the capsule and seed characters. Based on the assayed characters, the pale flax from Turkey was grouped into three clusters and these clusters were associated with site elevation and longitude, further confirming local genetic differentiation in pale flax from Turkey. These findings are significant for further studies of flax domestication history and useful for further exploitation of wild flax in genetic improvement of cultivated flax.  相似文献   
64.
65.
An experiment was conducted to determine the effects of optimal feeding frequency on growth performance, feed efficiency, nutrient utilization and body composition in juvenile flounder. Four feeding frequencies of one (F1), two (F2), three (F3) and four (F4) times a day were evaluated as treatments in triplicate for a period of 60 days. Forty-seven hatchery produced juveniles (2.5 ± 0.7 g) were stocked into 160-L rectangular fiberglass tanks and fed with a commercial diet containing 54 % protein to satiation. At the end of the experiment, the final weight of F1, F2, F3 and F4 were 5.06 ± 0.29, 5.91 ± 0.42, 6.24 ± 0.42 and 6.16 ± 0.46 g, respectively. Growth rates and feed consumption were highest in F3 and lowest in F1. Feed conversion ratios ranged between 0.83 ± 0.04 and 0.90 ± 0.03. There were no significant differences in either moisture or ash content of the fish groups. Protein content decreased with increasing feeding frequency, while lipid content partly increased with increasing feeding frequency. Nitrogen intake and lipid intake were significantly higher in fish fed under F3 and F4 treatment, whereas the nitrogen gain decreased and lipid gain increased with increasing feeding frequency. It is concluded that the flounder juveniles can achieve maximum growth performance and better nutrient utilization when they are fed a given ration two times a day. The findings have practical significance toward establishing an appropriate flounder nursery rearing and will directly benefit the nursery operations.  相似文献   
66.
Compatible segmented taper and volume functions were developed for Brutian pine, Cedar of Lebanon, and Cilicica fir in Turkey. The proposed models generally performed better for the whole tree, especially for Cilicica fir. Average diameter prediction error was less than 2.2 cm and average volume error was less than 0.009 m3. The proposed models provide needed merchantable stem volume and diameter estimates to any point in the bole based on the 10 relative height classes examined for the three species. Model estimates compared well to existing volume tables currently employed for these three important commercial species.  相似文献   
67.
Phosphorus (P) is one of the least available mineral nutrients to the plants in calcareous and alkaline soils. In this study, we investigated the synthesis, characterization and use of synthetic nano-hydroxyapatite (NHA), P uptake by plants as well as its residual effects. Soluble P source (H3PO4) was also included as treatment for comparison. NHA prepared by wet chemical techniques, characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and elemental dispersive X-ray (EDX) analysis. NHA and H3PO4 were applied at a rate of 200 mg kg?1 to find out their effects on phosphorus nutrition and growth of lettuce on the low and high calcareous soil. In addition to this, residual effects of NHA and H3PO4 were also determined for lettuce plants grown after first lettuce plants in the both soil. Dry weights of the first and second lettuce plants grown in low and high calcareous soil were significantly increased by applied phosphorus regardless of the source. NHA seems to be more effective than that of ordinary phosphorus source (H3PO4-P) on growth and P concentration of the lettuce plants. The promising results of this study needs to be supported with long term field studies regarding the uptake, translocation and interactions of nano-P with the other elements.  相似文献   
68.
A 12‐week feeding trial was conducted to estimate the effects of supplemented amino acids (lysine and methionine) with different dietary protein levels on growth, haematology and liver histology in meagre (Argyrosomus regius) at two different sizes: fingerling (15.2 g) and juvenile (44.4 g). Six practical diets were prepared, and three of these practical diets were formulated with 40 (P40), 44 (P44) and 48% (P48) crude protein without supplementation of amino acids. Other three diets having same protein levels were supplemented with lysine and methionine (P40AA, P44AA and P48AA) to bring these amino acids level up to that estimated to be at the least in the 48% protein diet. Final mean weight (FMW) and specific growth rate (SGR) of P48AA in fingerlings were higher than that of 40AA. According to FMW and SGR of juveniles, there was interaction found between dietary protein levels and the supplementation of amino acids. The FMW and SGR of meagre fed P44AA were higher than that of fish fed the other diets, except fish fed the P48. Economic profit index, packed cell volume and haemoglobin for juvenile meagre were significantly improved with the dietary protein level and amino acid supplementation. The liver tissues of the P48 group in both sizes displayed better structure compared with the other groups. In conclusion, dietary crude protein content of practical diets for juvenile meagre could be reduced from 48% to 44% by adding essential amino acids with an enhancement in growth, health and economic profit.  相似文献   
69.
The coalescence characteristics of oil droplets which are attached on flocs after coagulation is different from coalescence of droplets which are suspended in emulsions. The droplets attached on flocs are stationary and do not collide as those in emulsions. Objectives of this study were to investigate the change in size distribution of oil droplets that were attached on flocs after coagulation. The surface water–oil emulsion was prepared by mixing water, clay and ethyl benzene. Flocculation/coagulation experiments were conducted using standard jar test procedure and a polyelectrolyte. Microscopic images of flocs were taken at different times after the flocculation process and analyzed to characterize the changes in droplet size distribution as a result of coalescence and detachment of droplets from the flocs. Median droplet size increased during the first 40 h after the flocculation process and decreased after 45 h due to detachment of droplets from flocs. The number of droplets that were larger than 90 μm decreased over time. After 46 h, the flocs had very few oil droplets remaining attached and a significant fraction of the flocs settled to the bottom. Although the coalescence rate of oil droplets on flocs was slow, for oil–water separation applications, flocs should be removed from the solution as soon as possible to achieve higher separation efficiency of oil from the emulsion.  相似文献   
70.
In this study, the left and right cranial cervical ganglia (ganglion cervicale craniale) of eight young (four male, four female) domestic pigs weighing around 70-80 kg were inspected macro anatomically. The cranial cervical ganglion (CCG) was found cranio-ventrally of the distal ganglion of the vagus nerve, medial of the jugular process extremity, ventral of the atlas, dorsal of the epiglottis base and medial of the common root (CR) established by the internal carotid and occipital arteries. The internal carotid nerve and jugular nerve ramified from the cranial part of CCG. The jugular nerve gave branches that merged with the vagus and glossopharyngeal nerves. Other nerve branches originating from the cranial part of the ganglion reached to the external carotid artery and CR. The internal carotid nerve varied among cadavers in number of branches (two to four). These branches did not travel along the side of the internal carotid artery. The central part of CCG gave thin nerve branches that reached to various anatomical structures including the first and second cervical nerves, wall of the pharynx, accessory nerve, hypoglossal nerve, vagus nerve, external carotid artery and CR. The caudal part of CCG gave nerve branches that merged with the vagus, cranial laryngeal nerves, and common carotid artery. The external carotid nerves, which were two or three in number, also originated from the caudal part of CCG. In conclusion, the nerves ramifying from CCG of the pig varied in number among cadavers. Compared with literature raised in other species, there are also differences in number of nerve branches and course pattern of these nerves.  相似文献   
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