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91.
In two field trials (T1 and T2), the effect of two different extenders for buck semen was tested. Semen from six (T1) and seven (T2) bucks of the Norwegian Dairy Goat breed was diluted either in a milk‐based extender containing egg yolk (M) or in a commercially available extender without egg yolk [Andromed® (A)]. Dilution in M was performed in a two‐step procedure including centrifugation of the ejaculates and removal of the supernatant, while dilution in A was performed in one step. During the two trials (T1 and T2) 514 and 714, does, respectively, were artificially inseminated during natural oestrus, and the farmers performed the inseminations themselves after attending an artificial insemination (AI) training course. Vaginal insemination with 200 × 106 spermatozoa diluted in M resulted in a 25‐day non‐return rate (NRR) and kidding rate of 37.3% and 24.5%, respectively, while semen diluted in A resulted in 31.7% NRR and a kidding rate of 19.8% (T1). In T2, NRR and kidding rate for AI performed with semen diluted with M were 42.7% and 28.5%, respectively, while dilution in A gave 37.2% NRR and a kidding rate of 26.8%. There was no significant effect of extender in the two trials [T1:p = 0.068 (NRR), p = 0.148 (kidding rate), T2:p = 0.096 (NRR), p = 0.38 (kidding rate)], but farmer had a significant effect on the fertility parameters in both trials. In conclusion, the present studies may indicate that Andromed® is suitable for buck semen. However, more research is necessary to confirm the results and to improve the fertility of does after vaginal AI with frozen‐thawed semen.  相似文献   
92.
A seasonal variation of both particle and gaseous Hg concentrations in the atmosphere is present in south-western Sweden. An average gaseous Hg level of 3.7 ng m?3 is found in winter, compared to 2.8 ng m?3 in summer. A weak decreasing south-north gradient for gaseous Hg in air over the Nordic countries is also present, with yearly average values from 3.2 to 2.8 ng m?3. A gradient for particulate Hg is less clear. An air parcel trajectory sector classification of gaseous Hg levels in air, and to some extent the particulate associated Hg, clearly demonstrates the increased concentrations in the southern sectors, especially in south-western Sweden where the gaseous Hg increase is about I ng m?3. These observations are consistent with an influence from the European continent. The average concentrations of Hg in precipitation at the various stations show a pronounced decreasing south-north gradient. A major portion of the total Hg present in precipitation is associated with particles. For the southern stations, a strong correlation between Hg and sulfate, or pH, is present suggesting a connection between Hg in precipitation and anthropogenic activities.  相似文献   
93.
The influence of hydrological conditions and overburden type on the stream-water quality in a catchment effected by fine-grained sulfide-bearing sediments was studied. Water samples for measurement of pH and electric conductivity were collected at 16 sites along the main course of the stream during autumn and spring high water flow and during low and intermediate water flow. On one occasion (spring high-water flow) samples for analysis of total organic carbon were collected at these sites. Seventeen water samples for analyses of chemical elements (ICP-MS and ICP-AES) were taken within the catchment basin during autumn high water flow. The pH and conductivity of snow, and the geochemistry of the sulfide sediments were also studied. The occurrence of fine-grained sediments within the catchment was estimated from topographic and geologic maps and by visit to areas were the overburden type could not be determined from the maps. The hydrological conditions had a strong influence on the water quality. During high water flow in spring and autumn the concentrations of ionic components (conductivity) and hydrogen ions in the stream water were high, while the concentrations were much lower during low and intermediate water flow and when the ground was frozen. Extensive leaching of the sulfide-bearing sediments, which had higher contents of S and metals than the fine fraction of till in the study area, resulted in elevated contents of Li, Ni, Zn, Co, B, Al, Mg, U, Sr, Ca, K and Na in the stream water during autumn high water flow. The contents of Cr, Ba, Pb, Si and Fe in stream water were not much influenced by the type of overburden, while V was depleted in drainage waters from the sulfide sediments. Humic substances flocculated in the water in the middle section of the stream, which may have been caused by di- and trivalent metal cations leached in large quantities from the oxidizing sulfide sediments.  相似文献   
94.
The structure and aims of the Fédération Cynologique Internationale (FCI) are outlined, with a focus on the rules and regulations that are relevant to breeding and genetic health of dogs. Recently adopted strategies to enhance canine genetic health and activities to counteract exaggerated anatomical features are highlighted. Actions by the FCI regarding recognition of breeds and doping rules, under direct control by cynological organisations, are included, based on their relevance to canine health.  相似文献   
95.
Mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae), is a forest insect that undergoes intermittent population eruptions, causing landscape-level mortality to mature pines. Currently, an outbreak covers over 16.3 million ha of British Columbia and Alberta in western Canada. Recent incursion into the jack pine (Pinus banksiana Lamb.) of northwestern Alberta threatens further range expansion through the boreal forest to central and eastern Canada. The spread from British Columbia into northwestern Alberta has been facilitated by above-canopy dispersal of the insect by meso-scale atmospheric currents. At these scales, dispersing D. ponderosae may behave like inert particles, causing terrain-induced tropospheric convective and advective currents to influence population dispersal and establishment. We use spatial point process regression models to examine the association of meso-scale variables, including landscape features and their orientations, habitat suitability, elevation and treatment efforts, with occurrence of D. ponderosae infestations in 2004, 2005, and 2006. Infestations of D. ponderosae primarily established in canyons and valleys, before moving into more open-sloped areas. Southwestern slopes of midslope ridges and small hills, southwest facing open slopes, and valleys that run in a northeast–southwest cardinal direction were positively associated with higher intensities of infestation. This study provides insight into the influences of complex terrain on landscape disturbance by a forest insect, and can be used to prioritize areas for potential management.  相似文献   
96.
97.
Storm-felled trees left in the forest for a shorter or longer period, affect the quality of the logs. The change in quality is mainly because of attack of fungi and insects, which in turn depends on the moisture content (MC) of the sapwood. The purpose of this study was to receive more knowledge about drying of storm-felled trees by investigating how fast winter storm-felled Norway spruce and Scots pine dried when left in the forest. Sixteen storm-felled spruces with part of the roots still in ground contact were selected from three stands and in addition to 10 pines from one of the stands. The trees were examined for MC in the sapwood until 21 months after the storm. This study indicates that wind-thrown trees with roots still connected to the soil can survive one summer without any value loss caused by draught, fungi and insects. The stand conditions can be of importance as the storm-felled trees in the stand, with scattered windthrow, were in best condition after one year, as they were shadowed by the trees still standing. Comparing spruces and pines with the stand with scattered windthrow, pines were more sensitive to drought and reached critical MC earlier.  相似文献   
98.
Insulin-receptor binding in skeletal muscle of trout   总被引:2,自引:0,他引:2  
Two hundred rainbow trout (Oncorhynchus mykiss) age 0 +, weight range 11.3 – 11.5 g, were distributed randomly in two groups and maintained for five weeks on either 10% dextrin, or 20% dextrin diet. The fish were sampled 3–5 h and 18–20 h after the last feeding and insulin binding to partially purified insulin receptors in white and red skeletal muscles and to liver plasma membranes was assessed. Plasma insulin, plasma glucose, and liver glycogen content were analyzed in the same fish.Fish fed a diet with higher carbohydrate content (HC) had elevated insulin and glucose levels in peripheral blood, but lower liver glycogen contents compared to the fish fed a diet with lower carbohydrate content (LC). No growth retardation was observed in the fish from HC group.Three to five hours after the last feeding, insulin-receptor binding in white skeletal muscles was higher in HC group of fish, mostly because of an increase in number of high affinity binding sites. Eighteen to twenty hours after the last feeding this difference disappeared. In contrast, the specific binding of insulin to the liver plasma membranes appeared to be lower in the HC group of fish. The lower insulin binding to the liver plasma membranes observed 3–5 h after feeding, could be attributed to the lower quantity of binding sites, while the same phenomenon 18 h after feeding was likely a result of affinity changes. We conclude that higher glycemic levels observed in trout fed a HC diet as compared to LC group of fish, are not a consequence of impaired binding of insulin to its receptors in skeletal muscles.Presented in part at the Annual Meeting of American Society of Zoologists, December 26–30, 1989, Boston, U.S.A. Supported by a grant (Personal investigador en el extranjero) of Ministerio de Educacion y Ciencia, (CYCIT) Spain to J.G. and by grants of the U.S. National Science Foundation (DCB 8615551 and DCB 8915935 to E.P.) and North Atlantic Treaty Organization (NATO) 0926/87 to C. Ottolenghi and E.P.  相似文献   
99.
Market-based fisheries management systems give incentives to reduce the fleet size and employment, which increases earnings and contributes to resolve the tragedy of the commons. However, the often-stated expectation that economies of scale cause the disappearance of small-scale fishery is not observed in many cases. In this study, we investigate the effects on fleet structure in the period after introducing individual fishing quotas or individual fishing days with various degrees of transferability in selected fisheries in the seven Nordic countries. Despite observing economies of scale in most cases, it is found that the market-based fisheries management often does not reduce the small-scale fleet more than the fleet of large vessels. This is explained partly by small vessels targeting demersal species and large vessels pelagic species, and partly by the larger need of larger than small vessels to continuously utilize their capital stocks through fast adaptation to ensure return. A more important explanation is the regulation design, with limitations in sale of fishing rights and lease between vessel groups and regions and in the share of the total quota holdings of fishing rights by individuals and vessels. This is important for countries considering the introduction of market-based fisheries management, since the Nordic experiences show that with proper regulation design, economic gains can be achieved with small-scale fishing surviving even under economies of scale.  相似文献   
100.
A common limitation for the identification of novel activities from functional (meta) genomic screens is the low number of active clones detected relative to the number of clones screened. Here we demonstrate that constructing libraries with strains known to produce bioactives can greatly enhance the screening efficiency, by increasing the “hit-rate” and unmasking multiple activities from the same bacterial source.  相似文献   
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