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631.
中国与西方国家的生态工程比较   总被引:7,自引:0,他引:7  
生态工程正在世界上很多国家发展,但在中国与西方产生和发展的历史背景、社会、经济及当前科技水平有所不同,故在研究和应用目的、理论基础与发展现状、研究与应用对象、设计原则、技术路线、能源、生物多样性、价值等方面各有特点。为了取长补短、相互学习,以期推动生态工程在全球发展,本文比较了这些特点。  相似文献   
632.
我国生态教育体系建设   总被引:5,自引:0,他引:5  
生态教育是可持续发展的重要基础,文章分析了我国当前生态教育的现状和存在问题,提出生态教育体系建设的指导思想和终身教育、全民教育、分阶段实施、区别对待、因势利导的建设原则,构建了学校生态教育和社会生态教育的主要内容,对城乡生态教育不同侧重点进行了分析,并提出了保障该体系顺利建设的对策与措施。  相似文献   
633.
Keshan disease (KD) occurs in a wide geographic belt stretching from the Heilongjiang Province in northeastern China to Yunnan Province in southwestern China, including Huangling County, Shaanxi Province. In order to research relationships between eco-environmental geochemistry and KD pertaining to Se, Mo, B, Zn, Mn, and Cu, this investigation was conducted in the Jiantou KD area in Huangling County, one of the areas in China where the incidence of KD is highest. Environmental samples (rock, soil, plant and childrens hair) were collected from the area. Se in plants is low, ranging from 0.03 to 0.06 µg Se g–1 in corn, potato and soybean. Se contents in childrens hair are normal or reach the limitation of dangerous level. This study reports 0.18 µg Se g–1, B <40 µg g–1, and Mo <1.0 µg g–1 in aeolian soil, 0.14–0.38 µg Mo g–1 and 3–8 µg B g–1 in corn and potato (daily staple food for local human beings in the area). The Jiantou KD area is one where the elements Se, Mo and B are deficient. It is proposed that the deficiency of elements Se, Mo and B may be involved in the pathogenicity of KD with respect to the eco-environmental system because Se, Mo and B are essential micronutrients for plants and human beings. It seems that there is no significant relationship between the Zn–Mn–K–Pb–Ba associations and KD.  相似文献   
634.
我国东部七省生态系统对酸沉降的相对敏感性   总被引:1,自引:0,他引:1  
讨论了影响亚热带生态系统对酸沉降敏感性的生态因子,提出了敏感性等级划分的指标体系,根据大量资料编制了我国东部7省1市生态系统对酸沉降相对敏感性分区图。结果表明,在研究区域内生态系统的敏感性有相当大的差别,极敏感区和敏感区面积占全区总面积的1/3以上,主要分布在福建、浙江、江西3省。  相似文献   
635.
荒漠化是当今全球最严重的环境问题之一。结合中国国情来看,荒漠化不仅发生于干旱、半干旱地区;也发生于湿润、半湿润地区。中国已存在的荒漠化土地面积111.7万km ̄2,占国土面积的11.6%;其中风力作用、水蚀作用和物理及化学作用下的荒漠化土地约各占1/3。另外中国还有易受风力和水力作用影响的潜在荒漠化土地53.5万km ̄2和87.5万km ̄2,潜在盐渍化土地17.3万km ̄2。中国土地荒漠化是在脆弱生态条件下,人口过快增长,人为不合理的经营活动如水资源利用不当、过度开垦、过度放牧、过度樵采,以及工矿建设造成的土地与植被破坏、环境污染等所致,对它的防治实质上就是对退化环境的整治。中国荒漠化土地经过近几十年来的治理,个别地区有所好转,但总体上仍在发展中,因而它是环境保护与持续发展中的重要问题,必须引起重视。在总结中国防治荒漠化经验的基础上,提出了防治荒漠化的基本对策。  相似文献   
636.
Background Frequent application of Bordeaux mixture, which includes copper, as a fungicide in fruit and grape orchards may lead to copper accumulation in the soil, especially when orchard age and application times increase. The objectives of this study were: (i) to investigate the copper content and its spatial distribution in orchard soils; (ii) to identify the copper fractionation in soil and its relationship with plant uptake; (iii) to understand the characteristics of copper contamination in orchard soils. Materials and Methods Soil profile samples were taken in apple orchards with ages of 0, 5, 10, 20, 30 years and pot experiments were also carried out to study the effects of external copper input on copper fractionation. All soil samples were air-dried, ground and extracted with 0.43 mol L–1 HNO3 for the total absorbed copper. Fractionation determination was conducted following Tessier and Shuman sequential extraction methods, and copper was measured with AAS. Plant samples were first dry ashed, dissolved with 6 mol L–1 HCl and then copper and other elements were measured with ICP-MS.Results and Discussion Soil total Cu was higher in the apple orchards than that in non-orchard fields and was seen to have increased with orchard age. Soil Cu increased substantially with the average annual copper increase, ranging from 2.5 to 9 mg Cu kg–1. The distribution of copper in the soil profile was uneven, decreasing from surface to deeper layers, and the differences were significant, but the contents in every layer were also significantly correlated with those in the next layers. For all copper fractions, the organically bound, crystalline Mn oxide bound, and amorphous Fe bound fractions extracted with the Shuman method were much higher than the exchangeable and residual fractions. Using the Tessier method, organically bound, carbonate bound and Fe-Mn oxide bound fractions were much higher. With an increase in external copper input, the organically bound, crystalline Mn oxide bound and amorphous Fe bound fractions in the Shuman method and organically bound, carbonate bound and Fe-Mn oxide bound fractions in the Tessier method all increased significantly, while the changes in other fractions were not significant. Soil total copper and copper fractions were found to have good correlations with apple tree uptake. Copper in fruit flesh had significant correlations with soil total content in the 0–10 cm layer, all the copper fractions in the 0–5 cm layer, and some fractions in the deeper layers. Conclusion Copper content in orchard soils increased significantly with intensive application of Bordeaux mixtures and orchard age. Copper content decreased sharply from the topsoil to deeper soil layers. The copper contents in different layers also significantly correlated with those in the next layers. Dominant fractions of the copper in soil were mainly associated with organic matter, iron and manganese oxides and carbonates. A close relationship was found between the copper content in soils and in apple tree organs (which contained 8.9 to 66mg kg–1 Cu). Recommendation and Perspective Though most copper in the soil was specifically adsorbed or immobilized, and copper was mainly distributed in topsoil, which was essentially devoid of roots, the copper concentration of fruit still had significantly positive correlations with soil copper and most copper fractions. Therefore, measures must be taken to control copper accumulation in orchard soils and to make the apple fruit production sustainable.  相似文献   
637.
Croplands contribute to atmospheric nitric oxide (NO), but very limited data are available about NO fluxes from intensively managed croplands in China. In this study, NO fluxes were measured in a typical vegetable field planted with flowering Chinese cabbage (Brassica campestris L. ssp. Chinensis var. utilis Tsen et Lee), which is the most widely cultivated vegetable in Guangdong province, south China. NO emission drastically increased after nitrogen fertilizer application, and other practices involving loosening the soil also enhanced NO emission. Mean NO emission flux was 47.5 ng N m−2 s–1 over a complete growth cycle. Annual NO emission from the vegetable field was about 10.1 kg N ha−1 yr−1. Fertilizer-induced NO emission factor was estimated to be 2.4%. Total NO emission from vegetable fields in Guangdong province was roughly estimated to be 11.7 Gg N yr−1 based on the vegetable field area and annual NO emission rate, and to be 13.3 Gg N yr−1 based on fertilizer-induced NO emission factor and background NO emission. This means that NO emission from vegetable fields was approximately 6% of NOx from commercial energy consumption in Guangdong province.  相似文献   
638.
海洋环境污染监测是海洋环境管理的“耳目”和“哨兵”.离开海洋环境污染监测.海洋环境管理将寸步难行。在过去15年中,中国海洋环境污染监测工作取得了长足的进步,集中表现在三个方面:一是形成了从国家海洋环境监测中心一海区监测中心-管区-监察站的四级海洋环境监测体系;组建了由国务院有关部委、沿海11个省(市)、自治区等有关部门100多个单位2500人参加的全国海洋环境污染监测网;每年获取各类海洋环境污染监测数据十万余个,提供了估计全国海洋环境形势的基础。二是海洋环境污染监测工作有中国的特色。组织上实行了优化布点、分级管理,初步形成了有特色的监测网络体系;技术上推行站点网络化、布点采样规范化、分析方法标准化、数据处理计算机化、质量保证工作系统化规范化,具有自己特色的技术路线正在形成;管理上逐渐走上科学管理的道路。三是为海洋环境管理服务的能力有了明显提高。该文概略地介绍了中国海洋环境污染监测工作的全貌,全面地总结了中国海洋环境15年来的十条宝贵经验,宏观地描述了未来中国海洋环境污染监测的发展方向。  相似文献   
639.
In this study the frequencies of PM10 (as key urban pollutant) in 14 key environmental protection cities in northern China were analyzed. It follows that the PM10 concentration in the high-frequency period is higher with an extent 0.009–0.066 mg m−3 than in the low-frequency period of 2001–2002. Further the impacts of three kinds of dust events on the PM10 concentration in four cities (Beijing, Hohhot, Xi’an and Lanzhou) were explored. The results showed that different kinds of dust events have different influences on variation of PM10 concentration in these four cities. In Lanzhou and Hohhot, which are near the source areas of dust events, the contribution degree of these three dust events to the PM10 is: floating dust>dust storm>blowing dust. Whereas, in Beijing and Xi’an situated in dust event passing areas, the mean value of PM10 concentration is higher in blowing dust than in floating dust (no dust storm). In addition, the influences of dust events on PM10 concentration are different in the cities on different dust event paths. In Beijing and Hohhot (on the northern path), the high PM10 concentration is usually caused by blowing dust. But in both Lanzhou and Xi’an (on the western/northwestern path) the high PM10 pollution concentration is usually caused by floating dust.  相似文献   
640.
人为干扰对川西亚高山针叶林土壤物理性质的影响   总被引:23,自引:1,他引:23  
研究了川西亚高山针叶人工林在几种不同强度人为干扰下林地土壤物理性质。结果表明,随人为干扰强度的增加,土壤中细土(粉粒、粘粒)和大团聚体数量减少,小团聚体和原生土壤颗粒增加;土壤表层孔隙度减小,尤其是大孔隙明显减少;土壤有效水降低,持水供水能力减弱,渗透系数减小。川西亚高山人工针叶林土壤生态功能随人为干扰强度的增加而减弱,建议在最易受人为干扰的造林地区,最好是在造林初期封山育林。图1表5参13  相似文献   
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