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91.
92.
In Germany, Bio-beaker and infra-red irradiation (PSP) are used for beak trimming in turkey chicks as routine methods to prevent feather pecking and cannibalism. By both procedures the animals suffer from extensive damage and considerable continuous pain. Beak trimming is allowed by animal welfare legislation, but the operation requires an official permission and must be carried out under anesthesia. The official intention, due to animal welfare reasons, to decrease this operation and to question it permanently fails because beak trimming without anesthesia is tolerated. Elaboration of alternative programs has been demanded for a long time. Therefore selection of stocks tending less to cause feather pecking and cannibalism as well as adequate keeping and housing conditions during hatching and rearing are proposed.  相似文献   
93.
In Tabasco the petroleum industry pollutes soil recurrently by oil spills. We analysed Pb, V, Ni and Cr concentrations in water samples, and total metal contents and metal fractions in soil samples of contaminated and non-contaminated soils and in sediments. Besides, we determined Eh, pH, DOC and major ions in water and Eh, pH, Corg in soils and sediments. Sediments contained considerably larger heavy metal (HM) concentrations than soils. Local background concentrations of V, Ni and Cr in soils are larger than global means and oil spillages have not added these metals in quantities that exceed the natural variation. Spillage of formation water increases Pb concentrations in soils, particularly in mobile fractions. The contribution of the oil industry to HM loads is diluted by large fluvial water and sediment discharges and difficult to assess by comparison of total metal contents. Therefore, easily mobile metal fractions are much better indicators.  相似文献   
94.
Oxisols are a product of long and intense weathering. Their actual characteristics can neither be traced back to a certain climatic period, nor do they reveal the present soil-forming factors. In this paper, therefore, a reconstruction of the soil genesis of a strongly weathered Oxisol is attempted by comparing the present mineralogical status and the recent dynamics of selected elements with a nearby Inceptisol from the same catena. The parent rock of both soils is serpentinized dunite with nepheline-syenitic veins; the soil moisture regime is udic. Chemical and mineralogical parameters, as well as the concentration of elements in the soil solution of a Typic Haploperox and an Oxic Dystrochrept from the same catena were analyzed for one year. The dynamics of Si and Mg strongly depended on the state of weathering. In the saprolite of the Dystrochrept, Si is partially removed and partially fixed by the formation of quartz and mixed layer minerals. Mg is first fixed in mixed layer minerals, but is during consecutive weathering leached from the transition zone from saprolite to the oxic horizon. Due to the high redox potential, Fe is not soluble, forming goethite in the upper part of the saprolite. Al is also not removed and is finally fixed in kaolinite. In the weathered upper part of both profiles the concentration of Al, Si, Mg and Fe in the soil solution is too low to perceive a further weathering. The present dynamics of Fe, Al, Mg and Si and the mineralogical status of the Dystrochrept indicate that these processes are similar to those that have led to the formation of the Haploperox. The soils, therefore, developed exclusively by the relative enrichment of Al and Fe, the partial loss of Si and the almost complete loss of Mg. Desilification and ‘laterisation’ are hence processes occurring also presently under a tropical rain forest climate.  相似文献   
95.
96.
Linear–bilinear models are frequently used to analyze two-way data such as genotype-by-environment data. A well-known example of this class of models is the additive main effects and multiplicative interaction effects model (AMMI). We propose a new Bayesian treatment of such models offering a proper way to deal with the major problem of overparameterization. The rationale is to ignore the issue at the prior level and apply an appropriate processing at the posterior level to be able to arrive at easily interpretable inferences. Compared to previous attempts, this new strategy has the great advantage of being directly implementable in standard software packages devoted to Bayesian statistics such as WinBUGS/OpenBUGS/JAGS. The method is assessed using simulated datasets and a real dataset from plant breeding. We discuss the benefits of a Bayesian perspective to the analysis of genotype-by-environment interactions, focusing on practical questions related to general and local adaptation and stability of genotypes. We also suggest a new solution to the estimation of the risk of a genotype not exceeding a given threshold.  相似文献   
97.
Fiedler PC 《Science (New York, N.Y.)》1984,224(4654):1251-1254
Satellite infrared temperature images illustrate several effects of the 1982-1983 El Ni?o: warm sea-surface temperatures with the greatest anomalies near the coast, weakened coastal upwelling, and changes in surface circulation patterns. Phytoplankton pigment images from the Coastal Zone Color Scanner indicate reduced productivity during El Ni?o, apparently related to the weakened coastal upwelling The satellite images provide direct evidence of mesoscale changes associated with the oceanwide El Ni?o event.  相似文献   
98.
Influence of varied soil temperature and moisture on microbial activities under laboratory conditions Under laboratory conditions the influence of temperature (10°C, 20°C, fluctuation from 5° to 30°C within 12 h with additional freezing for 3 days) and soil moisture (30%, 60% w.h.c., remoistening to 60% for 1 week) on several microbial activities was investigated. The biomass-related, glucose-induced short-term respiration and the dehydrogenase activity (TTC reduction) were higher at 10°C in most cases as compared to 20°C. Independent of freezing fluctuating temperature caused the lowest activities. The nitrogen mineralization (including nitrification), however, was affected in the opposite way. No marked influences were observed with β-glucosidase, arylsulfatase, and alkaline phosphatase. In the sandy loam nearly no effects of the soil moisture occurred and in the loamy sand especially the dehydrogenase activity was higher at 30% w.h.c., whereas the nitrogen mineralization was lower. From the results it can be concluded, that ecological conditions favouring mineralization without substrate addition may even reduce microbial biomass by decomposition.  相似文献   
99.
Precipitation chemistry and atmospheric element-deposition in an agroecosystem at the North-Sea Coast of Schleswig-Holstein The objective of this study was to examine the chemistry of bulk precipitation and atmospheric element inputs in an arable soil near the North Sea coast of Schleswig-Holstein, North Germany. Bulk precipitation was collected at weekly intervals from November 1989 to October 1991. Precipitation amount, pH, electrical conductivity, and concentrations of Na+, K+, NH4+, Mg2+, Ca2+, Cl?, NO3?, and SO42? were recorded. The average volume-weighted pH was 5.5 and the average EC was 92 μS cm?1. Sodium and Cl? were with 64% and 76% the dominant ions (equivalent concentration) in bulk precipitation indicating the influence of the North Sea. The contribution of marine alkalinity to neutralization reactions of bulk precipitation was negligible (1%). The neutralizing substances NH3 (63%) and Carbonate (36%) were more important. Deposition rates were in 1990 and 1991 97.0 and 51.7 kg Na+ ha?1, 6.2 and 4.0 kg K+ ha?1, 15.0 and 8.4 kg Mg2+ ha?1, 13.2 and 10.4 kg Ca2+ ha?1, 12.3 and 9.5 kg NH4+-N ha?1, 8.0 and 5.9 kg NO3?-N ha?1, 168 and 83.1 kg Cl? ha?1 and 19.1 and 12.7 kg SO42?-S ha?1. In 1990 both more westerly winds and stronger wind-forces occurred than in 1991 and resulted in higher inputs of marine origin. Calculated on Cl? basis 93% of Na+, 55% of K+, 74% of Mg2+, 24% of Ca2+, and 36% of SO42? were of marine origin. Atmospheric input of marine origin supplied 39–72% of Mg and 21–37% of S requirement for crop production. The North Sea is an important source providing significant amounts of these elements to agricultural crops.  相似文献   
100.
Variance componentsare quantities of central interest in many applications, e.g., in cultivar yield stability analysis and in the analysis of measurement errors. In some applications, the feasible sample size is rather limited, leading to estimates of variance components that are subject to considerable sampling variation. For example, new crop cultivars are tested in only a few environments before release to the market, so the sample size for the variance across environments is small. Similarly, testing a new measurement instrument for some chemical compound may be costly, allowing only a limited number of replications. This article investigates the potential for improving the usual sample variance estimator by exploiting covariate information. In a cultivartrial, yield data may be available for only a few environments while meteorological data or data on a standard cultivar has been recorded for a very large number of environments. Likewise, in the analysis of measurement errors, there may be long-term data on a standard measurement procedure that can be used as a covariate to improve the variance estimate for a new instrument. It is shown in this article that the gain in accuracy achieved by using a covariate can be considerable, provided there is sufficient correlation between the covariate and the variable of interest.  相似文献   
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