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171.
172.
对微生物资源在农业可持续发展中的作用及其合理开发利用进行了阐述和总结。认为微生物作为一种宝贵的资源,它与农业可持续发展的关系十分密切,它在土壤肥力的提高与保持、营养元素的转化、环境净化与生态系统的平衡等方面起着极其重要的作用。因此,加强以微生物肥料、微生物农药、微生物食品、微生物饲料、环境激素和环境工程微生物等为核心的农业清洁生产技术的研究与开发利用将具有广阔的应用前景。微生物农业即所谓的"白色农业"将成为未来农业可持续发展的重要方向之一。 相似文献
173.
农村面源污染治理的政策与管理服务体系优化——以上海郊区农村为例 总被引:2,自引:0,他引:2
农村面源污染控制不仅是技术问题,也是管理体制与机制问题,探讨并完善农村面源污染治理的政策、管理与服务体系已成为当前研究的热点与难点。以上海郊区农村为例,梳理总结农村面源污染及其控制现状;在肯定当前治理效果的同时,识别其局限性,指出农业政策与环境保护政策的不协调、农村发展模式转变下制度与服务体系的相对滞后是根本原因;针对当前农村面源污染重要的贡献者——化肥、农药、畜禽粪便以及农村生活污水,分别从改革农业补贴制度、重构实现农村多重价值的制度以及完善农业生产服务体系等方面给出了治理的对策与建议。 相似文献
174.
研究了杭州市城郊文教居民区、风景旅游区、市郊农业区、市内商业区和市郊工业区等5种土地利用背景下的32个土样中8个重金属元素(Cd、Co、Cr、Cu、Ni、Pb、Zn、Mn)的含量和形态。结果表明,杭州市城郊土壤已受重金属的明显污染,其中以Pb的污染最为严重。污染程度为:市郊工业区>市内商业区>风景旅游区>文教居民区>市郊农业区。用连续提取方法对重金属分级表明,Cd、Co、Cr和Ni主要以残余态为主,平均占总量的60%以上,而Cu、Pb、Zn和Mn主要以酸可提取态、氧化物结合态和有机结合态存在,有较大的释放潜力和生物有效性。 相似文献
175.
农业绿色转型已经成为乡村振兴与农业农村深化改革的关键路径,亟待探索农业生产转型与其环境效应的耦合关系与机制,从而推进农业的高质量发展。近年来,学者们基于不同的空间尺度,对农业生产转型及其环境效应的过程、格局、机理与优化调控开展了广泛探讨。为系统梳理该方面研究的相关进展,识别出相应的研究不足,本文采用文献分析与系统归纳相结合的方法,分析了农业生态环境问题的识别、测度与成因等方面的研究态势,从关键要素的视角解析了农业生产转型对生态环境影响的研究进展,并对农业经济增长与农业面源污染和农业生产转型与农业生态效率的相互关系进行了总结。研究指出:未来农业生产转型及其环境效应研究应加强从系统科学的视角解读二者的互馈关系,并关注二者互馈响应的区域异质性,深化基于土地系统科学视角的耕地利用转型的环境影响研究,通过多学科交叉融合加强对中国特色“小农”生产方式转型所引发的环境问题的微观机理探析。 相似文献
176.
The Landscape Development Intensity index (LDI), which is based on non-renewable energy use and integrates diverse land use
activities, was compared to other measures of LU (e.g., %agriculture, %urban) to determine its ability for predicting benthic
diatom composition in freshwater marshes of peninsular Florida. In this study, 70 small, isolated herbaceous marshes located
along a human disturbance gradient (generally agricultural) throughout peninsular Florida were sampled for benthic diatoms
and soil and water physical/chemical parameters (i.e., TP, TKN, pH, specific conductance, etc.). Landscape measures of percent
agriculture, percent urban, percent natural, and LDI index values were calculated for a 100 m buffer around each site. The
strongest relationships using Mantel's r statistic, which ranges from −1 to 1, were found between benthic diatom composition, the combined soil and water variables,
and LDI scores (r=0.51, P<0.0001). Although similar, soil and water variables alone (r=0.45, P<0.0001) or with percent agriculture or percent natural were not as strongly correlated (both Mantel's r=0.46, P<0.0001). Little urban land use was found in the areas surrounding the study wetlands. Diatom data were clustered using flexible
beta into 2 groups, and stepwise discriminant analysis identified specific conductance, followed by LDI score, soil pH, water
total phosphorus, and ammonia, as cluster-separating variables. The LDI explained slightly more of the variation in species
composition than either percent agriculture or percent natural, perhaps because the LDI can combine disparate land uses into
a single quantitative value. However, the ecological significance of the difference between land use metrics and diatom composition
is controvertible, and additional tests including more varied land uses appear warranted. 相似文献
177.
为了使农用地级别划分和基准地价评估真正统一,以黄金坪水电站水库淹没区为例,将淹没区农用地划分为119个定级估价单元,在Arcmap/info,SPSS软件技术平台上,用回归分析法建立水库淹没区农用地定级因素与纯收益之间关系的综合模型,划分农用地级别,然后用收益还原法计算各级别基准地价。结果为:估算纯收益与实际纯收益间绝对误差为0.05元/m^2,相对误差为13.85%,相关系数达0.86;一级地价23元/m^2,二级地价19元/m^2,三级地价15元/m。,四级地价12元/m^2。表明:回归分析综合模型在淹没区农用地定级估价中取得了较理想的效果,使定级估价数据资料直接共享,省去了专家确定权重的难关,适合水库淹没区农用地市场不发育的现状。 相似文献
178.
生态农业发展与小城镇建设 总被引:4,自引:0,他引:4
以3家生态村为例说明乡镇企业在生态农业产值中占据主导地位。通过对乡镇企业的经济效益、环境效益和社会效益以及小城镇发展的优越性分析可知,乡镇企业不宜在农村发展,应该在小城镇中发展,农村生态建设要立足农业,通过减少土地的人口承载量,提高劳动生产率和增加农民收入。 相似文献
179.
Validation of an agricultural non-point source (AGNPS) pollution model for a catchment in the Jiulong River watershed, China 总被引:4,自引:0,他引:4
LIU Jianchang ZHANG Luoping ZHANG Yuzhen HONG Huasheng DENG Hongbing 《环境科学学报(英文版)》2008,20(5):599-606
This study tested and evaluated the agricultural non-point source(AGNPS)model for the Wuchuan catchment, a typical agricultural area in the Jiulong River watershed, Fujian Province. China. The AGNPS model was calibrated and validated for the study area with observed data onten storms. Thedata on eight stormsin 2002 were used for calibration while data on two stormswere used for validation of the model. Considering the lack of water quality data over a long-term series, a novel method, comparing an internal nested catchment with its surrounding catchment, was used to supplement the less long-term series data. Dual calibration and validation of the AGNPS model was obtained by this comparison. The results indicate that the correlation coefficients were 0. 99 and 0. 98 for runoff, 0. 94 and 0. 95 forthe peak runoff rate of the large catchment and the small catchment, respectively, and 0. 76 forthe sediment of the small catchment only. Each pair of correlation coefficients is homogeneous for the same event for the two catchments. With the exception of the sediment yield and particulate phosphorus, the peak nmofr rate and other nutrients were well predicted. Sensitivity analysis showed that the Soil Conservation Service curve number and rainfall quantity were the most sensitive parameters, which resulted in high output variations. Erosivitv and other parameters had little influence on the hydrological and quality outputs. 相似文献
180.
I. A. Romanenko V. A. Romanenkov P. Smith J. U. Smith O. D. Sirotenko N. V. Lisovoi L. K. Shevtsova D. I. Rukhovich P. V. Koroleva 《Regional Environmental Change》2007,7(2):63-77
This study estimates the consequences of climate change on cropland with and without implementation of adaptation measures,
paying special attention to the maintenance of soil organic carbon (C) stocks. We examine the possibility for regional sustainable
agricultural management practice that combines both maintenance and gain in soil carbon level with profit maximization. Future
scenarios of Regional Agricultural Production Systems (RAPS) were constructed for 2000–2070 based on linking the effects of
global climate change, predicted change in productivity parameters for the main agricultural crops, land-use and soil database
parameters. The RAPS were used to examine profitability and feasibility of alternative agricultural scenarios, based on an
economic model. A number of recommendations for decision making were proposed based on an assessment of the efficiency of
adaptation in animal husbandry and in the crop production sector, after analysis of current percentage of perennial grass
in rotation in comparison with future economic scenarios.
Figures in color are available at 相似文献