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81.
在实验室研究城市生物有机垃圾好氧和厌氧处理的生物降解能力,分析反应物质的输入和输出,研究好氧堆肥及厌氧消化反应过程中的参数变化,并得出相关结论:(1)堆肥过程中,箱体温度可以达到55℃以上,并持续3 d以上,达到无害化处理;堆肥过程中物料的pH值先降低后升高,最终稳定呈弱碱性,弱碱性pH值有利于提高土壤中阳离子交换能力,提高土壤肥力;(2)源分类后城市生物有机垃圾在堆肥处理的第一周减量化最明显,为21.23%,明显高于后2周,好氧生物降解率平均为63.20%;(3)沈阳市源分类生物有机垃圾实验室沼气产量为619 m3/(t VS),其中甲烷浓度平均为54.36%,沼气生物能为19.52 MJ/m3,厌氧生物降解率为70.14%。  相似文献   
82.
-  DOI: http://dx.doi.org/10.1065/jss2005.11.002 Background and Scope. Apart from their function as indicator or memory for local pollutant inputs, sediments, and especially sediment cores, can be used as a tool for assessing emissionimmission relationships of contaminants on a river-basin scale. Methods. In the framework of the SEDYMO program, source effects, i.e. intensity of sediment erosion under different shear stress, were investigated using a combination of core profile or sampling box studies in laboratory flumes and a mobile in-situ testing device for sediment stability. Results. Calculations of immission risks on downstream areas, e.g., from a three-step approach (substances of concern, areas of concern, areas of risk; Heise et al. 2004), may be directly confirmed from sediment core data, specifically from flood layers, at the target site.  相似文献   
83.
On-line capillary gas chromatography-isotope ratio mass spectrometry was used in the combustion (HRGC-C-IRMS) and the pyrolysis (HRGC-P-IRMS) modes to determine delta(13)C(PDB), delta(2)H(SMOW), and delta(18)O(SMOW) data of estragole (1) and methyl eugenol (2) originating from various sources. For 1, similar delta(13)C values, i.e., ranging from -35.4 to -29.9 per thousand and from -36.4 to -28.8 per thousand for the product of synthetic and natural origins, respectively, were found. The delta(2)H values ranged from -155 to -3 per thousand for synthetic 1 and from -193 to -105 per thousand for 1 from natural origin, whereas the determination of delta(18)O data gave values from +1.8 to +24.8 per thousand and from +2.7 to +18.7 per thousand for 1 from synthetic and natural origins, respectively. As synthetic 2 is produced by methylation of natural eugenol, the IRMS techniques did not allow differentiation of synthetic 2 from the product of natural origin. The recorded data ranges were nearly identical, i.e., delta(13)C = -37.4 to -35.0 per thousand and -41.1 to -32.2 per thousand; delta(2)H = -155 to -126 per thousand and -217 to -107 per thousand; delta(18)O = +5.5 to +6.6 per thousand and +2.7 to +6.9 per thousand, each for 2 from synthetic and natural origins, respectively.  相似文献   
84.
Acidity of throughfall precipitation is increased by the filtering of S and N from the atmosphere by trees. An element balance for a beech forest is given. As a consequence of acidification the soil chemical conditions are changed in a way that plants rooting close to the soil surface are affected. Losses of nutrients may pose a problem in forest plant nutrition in the near future in Central European forests on light or medium textured acid soils.  相似文献   
85.
In the optimisation of grain yield and quality of wheat, plant distribution is a key factor. In contrast to high yield levels, at moderate levels, widening the row space did not decrease grain yield. To gain information about changes in the quality and yield with changing in row spacings in organic farming systems, experiments were conducted at two locations in the Swiss midlands in 2001/2002. Winter wheat (Triticum aestivum L., cv. Titlis) was directly drilled in rows 0.1875 and 0.3750 m apart at the same seeding rate per area. An unfertilised treatment and the usual application of 60 m3 ha−1 liquid farmyard manure were compared. While the grain yield was not decreased by the wider row spacing, the thousand kernel weight (TKW), and grain protein content were increased from 42.6 to 43.5 g and from 11.7 to 12.7%, respectively, compared to the narrow row spacing. Liquid manure, on average of both experimental sites, increased the yield (from 3.725 to 4.765 Mg ha−1) and the grain protein content (from 12.0 to 12.5%). Doubling the space between the rows from 0.1875 to 0.3750 m seemed to be a suitable strategy for managing directly drilled winter wheat in organic farming systems.  相似文献   
86.
The purpose of this study was to gain knowledge about the micromorphology of the porcine common carotid artery (CCA) during the period of growth over the bodyweight range of 10–40 kg. CCA samples from German landrace pigs (DL) aged either 2 or 3 months (DL-2 and DL-3) were compared with samples from Göttingen minipigs (GM) aged either 18 or 40 months (GM-18 and GM-40) using transmitted light (phase-contrast mode) and transmission electron microscopy. The GM-18, GM-40 and the DL-3 groups had typical muscular artery histological characteristics. Contrasting to this, the 2-month-old DL pigs had a transitional artery type being characterized by a significantly higher proportion of elastic fibres and a significantly lower number of smooth muscle cells than did the 1 month older DL-3. During the period of maturation, the tunica media of the CCA in GM animals thickened by 1.3× and in DL animals by 2.5× resulting in an overall increased vessel wall thickness. The cumulated thickness of the tunica interna (endothelium, stratum subendotheliale and internal elastic lamina) and the tunica media (including the external elastic lamina) of DL-3 and GM-40 pigs were similar to each other and comparable to that of humans. With an increasing vessel wall thickness, the luminal diameter decreased in GM by 19% and in DL by 11%. Additionally, in the older age groups, GM-40 and DL-3, the internal elastic lamina principally was continuous, but there were also interrupted large segments of elastic lamina separated by gaps. In addition, the principal internal elastic lamina was duplicated in several places.  相似文献   
87.
The importance of the soil humus content is indisputable. Soil humus plays an important role in preserving soil fertility and exerts great influence on plant production and yield potential. However, proofing that management‐related changes in the stock of soil organic matter (SOM) have taken place against the background of spatial and temporal variation is a difficult task. In most cases, sampling over a long period of time is needed to verify these changes. Alternatively, potential changes in the SOM stock can be estimated using humus balancing models, which help to identify the need for humus reproduction on a farm. In general, a humus balance is the difference between the humus demand of cultivated crops and humus supply through crops and organic fertilizers. In this study, the ‘Dynamic Humus Unit Method' within the modelling program REPRO was applied to calculate the humus balance for 29 model‐farms that are representative of most of the agricultural production in Austria. Each model‐farm represents a specific production type (PT) and farming system in a defined region or main production area (MPA). This approach gives an overview of the humus balances at a large scale and allows a general trend in Austria to be estimated. Besides differing between conventional and organic farming systems, specific site conditions can also be selected in the model. The constructed model‐farms belong to different PTs such as “forage production”, “cash crops”, “refinement”, and “permanent crops”. The PT “permanent crops” refers to the cultivation of wine. The cropping system of each PT was analyzed in detail, while livestock keeping was considered only when applicable. Positive humus balances were found for all PTs except for permanent crops. The results ranged from –122 to 890 kg C ha?1 y?1. Regions and farm structure, e.g., forage production compared to cash crop, were found to have a greater influence than the kind of farming system (i.e., organic vs. conventional farming). Comparing the different PTs, forage production had the highest positive humus balances (219 to 890 kg C ha?1 y?1), followed by cash crop (24 to 239 kg C ha?1 y?1), refinement (–64 to 402 kg C ha?1 y?1) and permanent crops (–122 to –38 kg C ha?1 y?1). Regarding the farming system, organic farming led to more humus accumulation than conventional farming due to a higher share of fodder legumes and catch crops and more diverse crop rotations. The results were within the range of available empirical data on SOM change, and it was therefore concluded that the results are reasonable. In general, humus reproduction can be regarded as sufficient for agricultural production.  相似文献   
88.
Nuclear insulin-like growth factor 2 gene (IGF-2), growth hormone 1 gene (GH-1) and internal transcribed spacer 1 (ITS-1) of the ribosomal DNA as well as the mitochondrial NADH-3 and NADH-4 dehydrogenase genes (ND-3/4) exhibited species-specific restriction fragment patterns and three microsatellite loci (Sfo18, Ssa85 and Ssa197) had non-overlapping allele size ranges in Arctic charr and brook trout and were used as diagnostic markers for testing genetic purity of hatchery stocks and wild populations of Arctic charr and brook trout in Bavaria, Germany. Screening of four wild populations (three in Arctic charr and one in brook trout) revealed only a single hybrid (back-cross to brook trout) individual in L. Starnberg. In contrast, in three (out of five) hatchery stocks of Arctic charr and in both hatchery stocks of brook trout hybrids were detected with the frequency from 3 to 100%. Three hatchery stocks (SS2, SA and BS1) represent a hybrid swarm because they contained a very high proportion of hybrids (from 83 to 100%) and most or all hybrid individuals had alien alleles at only one or a few of six unlinked diagnostic loci, indicating that post-F1 hybrids represent the majority of individuals in these stocks and introgression has taken place. Release or escape of introgressed individuals from hatcheries into natural water bodies should be avoided in order to protect the biological diversity and genetic integrity of native fish populations.  相似文献   
89.
One feeding and two digestion experiments were performed in order to study the effect of feed processing by extrusion and pelleting on feed conversion and on the digestibility of energy, protein and amino acids. Feed conversion was 1·24 when trout was reared on an extruded diet as compared with 1·61 when reared on the same but pelleted diet. The specific growth rates of 1·56 and 1·55%, respectively, attained with both diets, were almost identical due to a depression of voluntary intake of the extruded diet. The effect of different daily feed intakes in percentage of body weight (NI, %) on the digestibility of energy (D, %) could be described using the following linear regression equations: D(%) = 78·3 ? 5·9 NI(%) for the pelleted diet and D(%) = 87·5 ? 3·9 NI(%) for the extruded diet. Though conversion of the extruded and pelleted diets differed significantly the digestible energy needed to produce 1 kg of gain was nearly the same, 17 370 kJ and 17 580 kJ respectively, indicating that differences in conversion were due to the digestible energy content. The digestion coefficients of the protein and amino acids were not influenced significantly (p < 0·05) by a change in the feed process, but different digestion coefficients for individual amino acids were observed. The use of digestible carbohydrate for trout nutrition is limited by the incidence of liver degeneration.  相似文献   
90.
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