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151.
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153.
中国黄土地区耕作侵蚀模拟 总被引:1,自引:3,他引:1
耕作侵蚀是国际上新近开展的一个研究领域。为了对中国黄土地区的耕作侵蚀规律进行定量描述,采用施放小立方块作为示踪材料进行耕作试验及测量来示踪和监测土壤运动,并通过相关分析与理论推导,对该地区的耕作侵蚀进行了模拟,获得了能够直接计算出坡面剖面任何一点净侵蚀模数的耕作侵蚀模型,结果表明,在采用当地由动物牵引的传统犁在坡面上自下而上进行往返横坡等高向下翻土耕作方式下:1)一次耕作导致的耕层土壤朝坡向方向平均水平运动距离随坡度的变化表现为线性相关;2)一次耕作导致的坡面剖面任何位置耕层断面的净侵蚀模数,受土壤容重、耕作深度、土壤与耕作条件决定的系数和地形曲率的影响。 相似文献
154.
155.
Alexandra D. Solomou Athanassios I. Sfougaris 《Communications in Soil Science and Plant Analysis》2015,46(4):317-325
The present study aimed to compare the woody plant species richness and cover (%) of five abandoned olive groves and five maquis ecosystems in central Greece and to describe the relationship between woody plant species richness and a set of environmental variables [soil pH, nitrogen (N), phosphorus (P), potassium (K), and organic matter; air temperature and humidity; altitude; slope; type of ecosystem; and presence of leaf litter]. Although woody plants are abundant in the abandoned olive groves, the number of species and amount of cover (%) are significantly greater in maquis. According to principal component analysis, woody plant species richness was positively correlated with soil organic matter, plant litter, and soil P and K in maquis. Also, woody plant species richness was positively correlated with slope in the abandoned olive groves. Olive grove ecosystems abandoned for at least 12 years have developed species compositions similar to the corresponding features of neighboring maquis, although the number of species and amount of cover (%) are significantly greater in maquis. 相似文献
156.
岔巴沟流域地貌形态分形特征量化研究 总被引:13,自引:2,他引:13
分形理论和方法为地貌学的非线性研究开辟了新的思路。本文基于分形基本理论和GIS技术,对地处黄土高原丘陵沟壑区第一副区的岔巴沟流域地貌形态分形特征进行了量化研究,提出了流域地貌形态特征分形信息维数的计算模型和方法,并依此获得了岔巴沟流域及各支流域的地貌形态特征分形信息维数。研究表明,岔巴沟流域及各支流域的地貌形态特征分形信息维数均小于1,且与流域面积保持很强的正相关;分形信息维数揭示了流域地貌形态复杂本质的量化特征,为黄土高原小流域侵蚀产沙预报模型中宏观地貌形态因子的量化提供了新的思路和方法。 相似文献
157.
María?C.?Camilión Marcelo?J.?Manassero Martín?A.?Hurtado Alicia?E.?RoncoEmail author 《Journal of Soils and Sediments》2003,3(3):213-220
Background, Aim and Scope. The compositional study of suspended matter in water from rivers of different latitudes and climates has revealed that the
fine fraction reflects both substrate lithology from source areas or topsoil composition along the course. Metal distribution
patterns are also strongly related to the clay mineral fate in fluvial aquatic systems. For the particular case of the coastal
area of the Río de la Plata estuary in South America, previous studies have, on the one hand, focused on the analysis of distribution
patterns of heavy metals in bottom river sediments and, on the other hand, on the assessment of metal contents in topsoils.
The present study was conducted to evaluate the Cu, Pb and Zn distribution in soils and sediments from four drainage basins
crossing two differentiated geomorphologic units composed of unconsolidated materials and to understand the metal behaviour.
Methods Data used included the existent, self-produced soil and sediment data sets (grain size, organic matter and Cu, Pb and Zn contents
from 124 samples). Analyses were performed by using standardised methods: grain size analysis by sieving and settling; organic
matter content based on the reduction of dichromate ion followed by titration; metal content by atomic absorption spectrophotometry
following acid digestion. Results and Discussion. The average (% w/w) clay and organic matter content were 45.9 ± 17.1 and
1.5 ± 1.7 for sediments and 32.0 ± 19.8, and 7.5 ± 7.6 for soils, respectively. The raw mean metal concentrations (mg-kg-1 dry weight) for sediments and soils were: Cu: 28.02 ± 27.28, 32.08 ± 21.64; Pb: 32.08 ± 46.94, 68.44 ± 69.25 and Zn: 83.09
± 150.33, 118.22 ± 74.20, respectively. A good correlation for each clay-normalised metal concentration was found between
soil and sediments using regression analysis considering average data for each basin sampling site (r > 0.89, p < 0.05). A
comparison between metal concentration levels taking into account geomorphologic units by a t independent sample test showed significant differences for the normalised soil-sediment metal data (p < 0.001), responding
to differences in grain size, clay mineralogy, organic matter and neoformed Fe-Mn oxide composition.
Conclusion, Recommendation and Outlook A clear parenthood between the topsoils and the bottom sediments in the study area was found. The Argiudolls from the inner
zone are frequently affected by rainwater erosion, which washes the fine materials with sorbed metals and carries them to
the streams. These watercourses reach the flat coastal plain, where soil flooding and bottom sediment depositional processes
predominate. Here, both soils and bottom sediments are enriched in clay, organic matter and metals. The topography and lithology,
under the environmental conditions of a temperate and humid climate control the fate of metals within these small basins.
The influence of the physical media on the distribution and fate of pollutants should not be minimised in the understanding
of the governing processes from natural systems. 相似文献
158.
Paolo Tarolli Giulia Sofia Simone Calligaro Massimo Prosdocimi Federico Preti Giancarlo Dalla Fontana 《Land Degradation \u0026amp; Development》2015,26(1):92-102
Vineyard landscapes are a relevant part of the European culture, and several authors concluded that they are the agricultural practice that causes the highest soil loss. Grape quality depends on the availability of water, and soil erosion is an important parameter dictating the vineyard sustainability; therefore, soil and water conservation measures are often implemented. Among them, the construction of terraces is the most widely used system. However, while favouring agricultural activities, terraces if not properly maintained can lead to local instabilities creating hazards for settlements and cultivations, and for the related economy. Terraced fields are also served by agricultural roads that can have deep effects on water flows triggering surface erosion. The goal of this research is to use lidar elevation data for a hydro‐geomorphological analysis of terraced vineyards. The work is divided in two parts. At first, the Relative Path Impact Index is tested in two vineyards to identify terrace‐induced and road‐induced erosions. Statistical thresholds of the Relative Path Impact Index are then defined to label the most critical areas. On the second step, using the index and the defined thresholds, we simulate different scenarios of soil conservation measures, establishing the optimal solution to reduce erosion. The results highlight the effectiveness of high‐resolution topography in the analysis of surface erosion in terraced vineyards, when the surface water flow is the main factor triggering the instabilities. The proposed analysis can help in scheduling a suitable planning to mitigate the consequences of the anthropogenic alterations induced by the terraces and agricultural roads. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
159.
江苏省土壤有机碳空间差异性以及影响因素研究 总被引:2,自引:0,他引:2
Soil organic carbon (SOC) plays a key role in the global carbon cycle.In this study,we used statistical and geostatistical methods to characterize and compare the spatial heterogeneity of SOC in soils of Jiangsu Province,China,and investigate the factors that influence it,such as topography,soil type,and land use.Our study was based on 24 186 soil samples obtained from the surface soil layer (0-0.2 m) and covering the entire area of the province.Interpolated values of SOC density in the surface layer,obtained by kriging based on a spherical model,ranged between 3.25 and 32.43 kg m 3.The highest SOC densities tended to occur in the Taihu Plain,Lixia River Plain,along the Yangtze River,and in high-elevation hilly areas such as those in northern and southwest Jiangsu,while the lowest values were found in the coastal plain.Elevation,slope,soil type,and land use type significantly affected SOC densities.Steeper slope tended to result in SOC decline.Correlation between elevation and SOC densities was positive in the hill areas but negative in the low plain areas,probably due to the effect of different land cover types,temperature,and soil fertility.High SOC densities were usually found in limestone and paddy soils and low densities in coastal saline soils and alluvial soils,indicating that high clay and silt contents in the soils could lead to an increase,and high sand content to a decrease in the accumulation of SOC.SOC densities were sensitive to land use and usually increased in towns,woodland,paddy land,and shallow water areas,which were strongly affected by industrial and human activities,covered with highly productive vegetation,or subject to long-term use of organic fertilizers or flooding conditions. 相似文献
160.
为研究我国马铃薯收获损失大小及其影响因素,在广东、内蒙古和甘肃3省共11个地块进行田间小区试验,测试不同收获方式、地块和品种下的马铃薯收获损失率的变化情况。研究发现:相较于传统的人工收获方式,机械化收获尽管效率高,但由于机械适用性方面的限制,收获损失率也高;地形尤其是土壤条件对马铃薯机械收获损失有很大影响,在其他收获条件相同的情况下,低洼地、土壤有板结地块中的机械收获损失率明显高于平地;品种主要对马铃薯机械收获的损失有直接影响,块茎体形大、生长深、结薯不集中的马铃薯品种,机械收获的损失率相对更高。 相似文献