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571.
大力发展低碳经济,是山西省转变经济发展方式、实现可持续发展的必由之路.本文从产业结构、能源结构、碳排放强度、以及山西省在全国的碳排放水平等方面分析了山西省的碳排放特征,在此基础上提出山西省的低碳发展策略.  相似文献   
572.
文章运用了能值分析方法进行了碳排放核算,核算帐户不仅包括能源消耗产生的二氧化碳,也包括生物质资源消费和废弃物排放所产生的二氧化碳。并在此基础上,将人口、经济和二氧化碳排放量综合起来考虑,引入对污染敏感的收入指数衡量一个地区碳排放绩效。并通过对天津市、上海市、北京市及重庆市2001年-2011年数据,分析和衡量四市将人口、经济和二氧化碳排放量综合考虑碳的排放绩效,通过案例区研究表明将全碳排核算的计算结果与经济、社会因素统一在同一个指标中,更加有利于区域对环境、经济和社会做全面考虑。  相似文献   
573.
我国绿色物流的发展现状和应对措施   总被引:6,自引:0,他引:6  
所谓绿色物流,就是以降低对环境的污染、减少资源消耗为目标的物流活动。但是,绿色物流的理念才刚刚传入我国,对政府和企业而言都还是一个全新的话题,不少企业对其重要性还缺乏认识。对此,政府应该根据5R原则对企业进行规制与政策激励,加强企业的环境自律和消费者的绿色理念宣传,把绿色理念的传播贯穿全社会。  相似文献   
574.
The theoretical value of encounters with parasitized hosts for parasitoids   总被引:1,自引:1,他引:0  
A female parasitoid searching for hosts in a patch experiences a diminishing encounter rate with unparasitized and thus suitable hosts. To use the available time most efficiently, it constantly has to decide whether to stay in the patch and continue to search for hosts or to search for and travel to another patch in the habitat. Several informational cues can be used to optimize the searching success. Theoretically, encounters with unparasitized hosts should lead to a prolonged search in a given patch if hosts are distributed contagiously. The results of empirical studies strongly support this hypothesis. However, it has, to date, not been investigated theoretically whether encounters with already parasitized hosts (which usually entail time costs) provide a parasitoid with valuable information for the optimization of its search in depletable patches, although the empirical studies concerning this question so far have produced ambiguous results. Building on recent advances in Bayesian foraging strategies, we approached this problem by modeling a priori searching strategies (which differ in the amount of information considered) and then testing them in computer simulations. By comparing the strategies, we were able to determine whether and how encounters with already parasitized hosts can yield information that can be used to enhance a parasitoid’s searching success.
Munjong KolssEmail: Phone: +41-26-3008856Fax: +41-26-3009698
  相似文献   
575.
针对简易瞬态工况法机动车尾气排放检测过程中层出不穷的违规检测现象,为对其检测过程实施有效监管,通过分析简易瞬态工况法的检测原理,筛选出可用于监管的车辆基准质量、(CO+CO2)浓度、O2浓度、实时检测尾气流量4个参数,分析其用于监管的原理和理由,并通过五气分析仪漏气实验和实测尾气流量异常案例验证其监管可行性,以期为监管...  相似文献   
576.
The measurement of urban population carrying capacity is the basis for cities' sustainable development. However, the traditional study on population carrying capacity which was based on food supply is not applicable to the single urban area. This paper built a model for the analysis of urban carrying capacity, and took Haidian District in Beijing as an example to calculate the urban carrying capacity of Haidian District in the future, which was the basis for the improvement of the population carrying capacity. This study would also provide a reference to the measurement of the urban population carrying capacity for other cities and districts in China.  相似文献   
577.
The measurement of urban population carrying capac- ity is the basis for cities' sustainable development.However,the traditional study on population carrying capacity which was based on food supply is not applicable to the single urban area.This paper built a model for the analysis of urban carrying capacity, and took Haidian District in Beijing as an example to calculate the urban carrying capacity of Haidian District in the future,which was the basis for the improvement of the population carrying capac...  相似文献   
578.
Fluctuations in the abundance of insular groups of sea otters on the Commander Archipelago are analyzed with regard to changes in meteorological conditions. The main factors responsible for the abrupt decline of the Bering Sea group between 2002 and 2004 are discussed. A statistically significant correlation has been revealed between fluctuations of sea otter abundance and the cycles of solar activity in the period since 1992. Changes in the age and sex structure of the insular groups of sea otters are evaluated.  相似文献   
579.
在中国城市化迅速发展的背景下.城市人口、经济、空间与城市环境的矛盾日益复杂和激化,从可持续发展的角度出发.迫切需要研究城市人口、经济、空间与城市环境之闻的协调关系。运用主成分分析和回归分析等方法。在市区尺度上构建城市人口、经济、空阃与城市环境的协调评价体系,并以老工业城市沈阳为例,进行实证分析。分析结果表明:沈阳城市人口经济空间的综合发展于1993—1999年处于困境.2000年以后城市综合发展逐步好转;沈阳城市环境在1998年以后稳定上升;沈阳城市综合发展与城市环境的静态协调度具有明显的阶段性和波动性特征,动态协调度具有平滑和滞后性的特点;静态协调度于1993—1994年属于基本不协调阶段.1995—2005年基本处于协调状态。于1999年出现了低谷。并存在着下降的趋势;动态协调度于1993—1996年属于基本不协调阶段。1997年以后总体上属于基本协调阶段。  相似文献   
580.
The continuous growth of world population and the intensification of urbanization process create a challenge to environment quality and sustainable development around the world. In this paper I tried to conduct a forecast analysis of near-future urbanization related population growth worldwide, based on recent demographic trends. Such an analysis can provide important insights into the prospects for changes in the size and composition of world population and in urbanization process. Optimal polynomial functions were used to fit historical trajectories of population dynamics, and the detailed forecasts of the population mainly over the period 2010–2030 were conducted and analyzed. If the past pattern continues, world total population would increase to 7.94–8.33 billion in 2030 and the annual growth is expected to continually decline in the forecast period. Global total population would stop increasing during the period 2050–2060 and would not exceed 9.5 billion in the future. The total population of Africa, Asia, Oceania, South America, North & Central America would separately increase to 1.35–1.41, 4.86–5.65, 0.04–0.05, 0.44–0.45, and 0.71–0.72 billion in 2030. Europe’s total population is forecast to decline to 0.64–0.67 billion in 2030. World’s rural population is expected to grow to the maximum during the period 2015–2020 and would greatly decline after that period. Global rural population would reach 3.12–3.41 billion in 2030. Rural population in Asia and Africa is estimated to increase and achieve the maximum around 2025 and decline thereafter. For other regions, the rural population would continually decline in the forecast period. Urban population in the world would continually grow and reach 4.72–5.00 billion in 2030, an increase of 48.6–57.8%. However the annual growth of urban population is expected to increase to the maximum (6.86 million/year) during the period 2020–2025 and then decline in the following years. Urban population is projected to continually grow in all regions excepting Europe. Europe’s urban population is expected to decline in the period 2010–2030. Urbanization process worldwide, represented by the ratio urban population versus total population (RUT) and the ratio rural population versus urban population, is expected to continue during the period 2010–2030. The RUT of the world is projected to reach 0.5 before 2010 and would continue to increase in the forecast period. Global RUT is estimated to reach 0.56 in 2030. However, the regional patterns of urbanization process would be diverse. Europe’s RUT is estimated to continually decline in the forecast period and reach 0.68 in 2030. The RUT for Africa and Caribbean would continually increase before 2030, while the RUTs for Asia and South America are estimated to achieve their maximums around 2025 and decline in the following years. Oceania and North & Central America would thoroughly realize urbanization (≈1) during the periods 2020–2025 and 2025–2030. The expansion of world population and urbanization will continually exert a stronger stress to environment quality and sustainable development in a near future. However we may expect this situation would start to change from mid-21st century after total population has achieved its maximum. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
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