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541.
Effluents from wastewater treatment plant (WWTP) have been reported to have a broad spectrum of endocrine disrupting compounds (EDCs). The majority of studies have focused on the occurrence of estrogenic activity, while ignoring nuclear hormone receptors (NRs) pathways. In the present study, a battery of in vitro yeast bioassays and a cell bioassay, including antagonistic and agonistic effects on estrogen receptor (ER), androgen receptor (AR), progesterone receptor (PR), estrogen- related receptor (ERR) and aryl hydrocarbon receptor (AHR), were conducted to evaluate the removal efficien- cies of EDCs by different treatment processes of a WWTP located in Beijing. Estrogenic, anti-estrogenic, anti- androgenic, anti-progesteronic, anti-ERR and the activa- tion of AHR activities were detected in samples from all treatment processes and the receiving water. The concen- tration of estrogenic contaminants with estradiol (E2) equivalent concentrations ranged from 0.82 x 10-9 to 3.54 x 10 9g Ee_EQ.L-1. The concentration of anti-estrogenic contaminants with 4-hydroxytamoxifen (4-OHT) equiva- lent concentrations ranged from 1.24 × 10-6 to 2.36 x 10-6 g 4-OHT-EQ.L-1. The concentration of anti-androgenic contaminants ranged from 2.21 x 10-s to 3.52 × 10-6g flutamide-EQ. L-1. The concentration of anti-progesteronic contaminants ranged from 3.15 x 10^-5 to 2.71 x 10^-4g RU486-EQ. L-1. The concentration of anti-ERR contami- nants ranged from 7.09 x 10-5 to 6.50 x 104 g 4-OHT-EQ × L^-10. The concentration of AHR activators ranged from 1.7 × 10-10 to 3.4 × 10^-10g TCDD-EQ-L-1. These processes including secondary clarifier, coagulation, as well as coal and sand filtration could eliminated 67.2% of estrogenic contaminants, 47.0% of anti-estrogenic contaminants, 98.3% of anti-androgenic contaminants, 88.4% of anti- progesteronic contaminants, 65.4% of anti-ERR contami- nants and 46.9% of AHR activators. WWTP effluents contain multiple receptor disruptors may have very complex adverse effects on exposed organisms.  相似文献   
542.
Contemporary human activities such as tropical deforestation, land clearing for agriculture, pest control and grassland management lead to biomass burning, which in turn leads to land-cover changes. However, biomass burning emissions are not correctly measured and the methods to assess these emissions form a part of current research area. The traditional methods for estimating aerosols and trace gases released into the atmosphere generally use emission factors associated with fuel loading and moisture characteristics and other parameters that are hard to estimate in near real-time applications. In this paper, fire radiative power (FRP) products were extracted from Moderate Resolution Imaging Spectroradiometer (MODIS) and from the Geostationary Operational Environmental Satellites (GOES) fire products and new South America generic biomes FRE-based smoke aerosol emission coefficients were derived and applied in 2002 South America fire season. The inventory estimated by MODIS and GOES FRP measurements were included in Coupled Aerosol-Tracer Transport model coupled to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS) and evaluated with ground truth collected in Large Scale Biosphere–Atmosphere Smoke, Aerosols, Clouds, rainfall, and Climate (SMOCC) and Radiation, Cloud, and Climate Interactions (RaCCI). Although the linear regression showed that GOES FRP overestimates MODIS FRP observations, the use of a common external parameter such as MODIS aerosol optical depth product could minimize the difference between sensors. The relationship between the PM2.5μm (Particulate Matter with diameter less than 2.5 μm) and CO (Carbon Monoxide) model shows a good agreement with SMOCC/RaCCI data in the general pattern of temporal evolution. The results showed high correlations, with values between 0.80 and 0.95 (significant at 0.5 level by student t test), for the CATT-BRAMS simulations with PM2.5μm and CO.  相似文献   
543.
 Summer phytoplankton assemblages from surface waters off Kuwait were enriched with levels of eolian dust (105, 106, and 107 mg/m3), similar to seasonal dust fallout for this region. Algal growth was positive and dose dependent. Highest biomass was up to 527 μg chlorophyll a/l on day 5. The maximum doublings of biomass per day were 0.64, 0.77, and 1.42, corresponding to 105, 106, and 107 mg/m3 enrichment and were significantly higher than the 0.56 for control. Changes in the phytoplankton species composition occurred with changes in biomass, with small algae dominating peak populations. It is suggested that through enrichment of trace elements via eolian dust, a high level of phytoplankton biomass and growth can be sustained in this arid environment. Received: 15 October / Accepted in revised form: 16 June 1999  相似文献   
544.
稀土湿法冶炼废水处理与资源化研究   总被引:3,自引:0,他引:3  
对某稀土湿法冶炼工艺进行了以清洁生产为核心的技改方案研究,在清洁工艺设计的基础上,通过工艺原理分析和试验,说明其革新工艺的经济有效性;从酸浸废液中年回收硫酸亚铁3000t,从碱转废液中年回收硫酸钠3000t;从废水回收冰晶石,氟回收86%;  相似文献   
545.
白永峰  顾强 《环境科技》1999,12(3):26-28
排污收费制度是中国环境政策中一个核心的管理手段。它是我国为强化环境管理,运用经济手段,促进工业企业污染防治的一个独特的制度。在新的市场经济体制下和环境目标下,这项制度已不能适应社会主义市场经济发展的需要,因而在必要进行改革以适应新形势下环境保护工作的需要。在分析现行排污收费制度基础上,对我国现行的收费制度、政策和标准等的改革提出见解。  相似文献   
546.
Many animals use body coloration as a strategy to communicate with conspecifics, prey, and predators. Color is a trade-off for some species, since they should be visible to conspecifics but cryptic to predators and prey. Some flower-dwelling predators, such as crab spiders, are capable of choosing the color of flowers where they ambush flower visitors and pollinators. In order to avoid being captured, visitors evaluate flowers visually before landing. The crab spider Mecaphesa dubia is a polymorphic species (white/purple color morphs), which inhabits the flower heads of a dune plant, Palafoxia lindenii. Using full-spectrum photography of spiders and flowers, we evaluated how honeybees perceived the spiders at different distances. Using visual modeling, we obtained the chromatic and achromatic contrasts of the spiders on flower heads as perceived by honeybees. Purple morphs were found mainly on the receptacle area and white morphs were equally likely to be found in the flowers and receptacle. According to theoretical modeling, white morphs were visible to honeybees from a distance of 10 cm in receptacle area but appeared to be cryptic in the flower area. Purple morphs were cryptic on the receptacle and less so when they were on the flowers. Spiders on flower heads are predicted to be more easily detected by honeybees using chromatic contrast. Our study shows that the conspicuousness of flower dwelling spiders to honeybees depends on the color morph, the distance of observation, and the position of spider on the flower head.  相似文献   
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549.
Air pollution is increasingly recognized as a significant contributor to global health outcomes. A methodological framework for evaluating the global health-related outcomes of outdoor and indoor (household) air pollution is presented and validated for the year 2005. Ambient concentrations of PM2.5 are estimated with a combination of energy and atmospheric models, with detailed representation of urban and rural spatial exposures. Populations dependent on solid fuels are established with household survey data. Health impacts for outdoor and household air pollution are independently calculated using the fractions of disease that can be attributed to ambient air pollution exposure and solid fuel use. Estimated ambient pollution concentrations indicate that more than 80% of the population exceeds the WHO Air Quality Guidelines in 2005. In addition, 3.26?billion people were found to use solid fuel for cooking in three regions of Sub Saharan Africa, South Asia and Pacific Asia in 2005. Outdoor air pollution results in 2.7?million deaths or 23?million disability adjusted life years (DALYs) while household air pollution from solid fuel use and related indoor smoke results in 2.1?million deaths or 41.6?million DALYs. The higher morbidity from household air pollution can be attributed to children below the age of 5 in Sub Saharan Africa and South Asia. The burden of disease from air pollution is found to be significant, thus indicating the importance of policy interventions.  相似文献   
550.
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