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431.
环保投资增长规律及其模型研究   总被引:1,自引:0,他引:1  
孙冬煜 《四川环境》2002,21(3):29-32
本文从国内外环保投资的实践入手,分析和总结出环保投资长期增长规律,并依据环境-经济-社会的技术经济关系,建立起“污染平衡方程式”,从理论上对该规律进行了证明,这样旨在为环保投资决策 参考依据,使其科学化和合理化,从而促进环境与经济的协调发展,保证我国可持续发展战略的顺利实施。  相似文献   
432.
从室内微环境生态平衡的构成及其打破这种平衡的因素出发,详细探讨了室内微环境生态平衡对人体健康的重要性,并进而指出:为了减少疾病的发病率,就应首先从改善室内微环境生态平衡作起,这也是控制疾病的最佳途径.  相似文献   
433.
ABSTRACT: An irrigation model based on a modified Thornthwaite water balance was used to simulate the effects of various hypothetical climatic changes on annual irrigation demand in a humidtemperate climate. The climatic-change scenarios consisted of combinations of changes in temperature, precipitation, and stomatal resistance of plants to transpiration. The objectives were to (1) examine the effects of long-term changes in these components of climatic change on annual irrigation demand, and (2) identify which of these factors would cause the largest changes in annual irrigation demand. Hypothetical climatic changes that only included increases in temperature and changes in precipitation resulted in increased annual irrigation demand, even with a 20 percent increase in precipitation. The model results showed that, for the ranges of changes in temperature and precipitation used in this study, changes in irrigation demand were more sensitive to changes in temperature than to changes in precipitation. Model results also indicated that increased stomatal resistance to transpiration counteracted the effects of increases in temperature and decreases in precipitation on irrigation demand. Changes in irrigation demand were even more sensitive to changes in stomatal resistance than to changes in temperature. A large amount of uncertainty is associated with predictions of future climatic conditions; however, uncertainty associated with natural climatic variability may be larger and may mask the effects of climatic change on irrigation demand.  相似文献   
434.
蔡正帮 《四川环境》1992,11(3):35-40
本文运用生态学原理,恢复沱江流域生态,以增流量;运用生态工程治理污染,平衡水体生态。从总本上提出了防治沱江水质污染的措施。  相似文献   
435.
黄河山东段断流的成因及对策   总被引:1,自引:0,他引:1  
近年来黄河下游断流时段、断流河段逐年延长, 断流开始日期逐年提前, 下游黄河面临决口改道的险境。同时, 下游的经济发展受到很大损失, 生态平衡受到严重破坏。本文分析产生的原因、指出危害、总结过去认识上的不足、探讨性的提出解决的对策  相似文献   
436.
ABSTRACT. Most of Utah's rapid population and industrial expansion is taking place along the western base of the Wasatch Mountains, with consequent increases in water demand. As a part of Utah's “Developing a State Water Plan,” a foundation investigation of the Utah Lake drainage area, which is at the Southern end of the Wasatch Front, was completed which delineated the quantity and quality of the water resources, present water uses, and opportunities for further water conservation. To prepare water budgets, land use data was collected to delineate all areas using water in excess of normal precipitation, which includes agricultural croplands, phreatophytes, open water surfaces, industrial areas, and urban areas. The water budgets were prepared for the time base 1931-1960, but adjusted to physical conditions existing in 1960. The Initial Phase of the Bonneville Unit of the Central Utah Project is presently under construction, with costs expected to exceed 300 million dollars. The principal feature of this project is the exportation of waters from the Colorado River Basin into the Utah Lake drainage area (Great Basin). This importation provides a large number of alternatives for allocation, reallocation of present supplies, and exportation. The possible effects of the Central Utah Project for realizing some of the above alternatives is delineated. Fortunately, the features of this project allow a wide latitude for water management in Utah, thereby facilitating its corporation into a “State Water Plan.”  相似文献   
437.
Stable isotope (18O–H2O, 2H–H2O 34S–SO4 2-) andhydrochemical data (SO4 2-, Fe-concentrations) have beenused to estimate the annual groundwater inflow and outflow of mining lake ML 111 and to calculate the total amount of dissolvedsulfate and iron that is carried into the lake by groundwater. The hydrological balance suggests an annual groundwater inflow of 23 700 m3 and an annual groundwater outflow of 15 700 m3. The calculation of the sulfur and iron balances yielded an annual sulfate input of 37 800 kg and an annual iron input of 7000 kg with the groundwater inflow. Furthermore it was shown that significant fluxes of these elements go into the lake sediments which results in continuous release of acidity in the lake water.  相似文献   
438.
To simulate the behavior of agricultural mulch coextruded poly(lactic acid)(PLA)/starch films, two stages were carried out. The first was an ultraviolet treatment (UV) at 315 nm, during which glass transition temperature Tg, weight, and molecular weight (MW) decreased and a separation between PLA and starch phase was observed. For the second stage, the mineralization of the carbon of the material was followed using the ASTM (D 5209–92 and 5338–92) and ISO/CEN (14852 and 14855) standard procedures. To measure the biodegradability of polymer material, the assessment of the carbon balance allowed determination of the distribution between the carbon rate used to the biomass synthesis or the respiration process (released CO2), as well as the dissolved organic carbon into the culture medium and the carbon in the residual insoluble material. The influence of the nature of the medium and the standardized procedures on the final rate of biodegradation was investigated. Whatever the standardized method, the biodegradation percentage was significantly stronger in liquid medium (92.4–93.4) than on inert medium (80–83%). In the case of the compost process, only released CO2 was measured and corresponded to 79.1–80.3%.  相似文献   
439.
通过对人类社会生态环境系统物质循环全过程的研究得出:实现资源高效可持续利用是实施可持续发展战略的关键;实施可持续经济发展战备必须从人类社会经济系统发展的全过程考虑;生产环节要推行清洁生产和标准化管理;消费领域要倡导绿色消费方式;发展循环经济,减少人类活动对自然环境的压力。  相似文献   
440.
Source resolution and risk apportionment of emission source categories for risk reduction purposes can be used to enhance the Bubble Policy of the Clean Air Act. This is performed by incorporating receptor modeling techniques of factor analysis and chemical mass balances to assess noncarcinogenic and carcinogenic inhalation risks to a target population for certain pollutants coming from major emission source categories in a steel plant air shed. Source resolution, using factor analysis, statistically interprets a “source” from ambient data. By subsequently quantifying risks from identified metal emission sources using chemical mass balances and risk apportionment, a total additive risk from main source contributors in the steel plant is estimated. From this methodology, the Bubble Policy can be enhanced by targeting only main risk sources or by “risk-trading” with minor impact sources to reduce the total risk (if deemed significant) without arbitrarily reducing risk for all sources in an industrial source complex’s “bubble.”  相似文献   
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