首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2454篇
  免费   11篇
  国内免费   7篇
安全科学   42篇
废物处理   87篇
环保管理   146篇
综合类   758篇
基础理论   437篇
环境理论   7篇
污染及防治   749篇
评价与监测   136篇
社会与环境   104篇
灾害及防治   6篇
  2022年   36篇
  2021年   33篇
  2020年   18篇
  2019年   22篇
  2018年   55篇
  2017年   57篇
  2016年   78篇
  2015年   43篇
  2014年   90篇
  2013年   145篇
  2012年   66篇
  2011年   127篇
  2010年   78篇
  2009年   84篇
  2008年   122篇
  2007年   112篇
  2006年   92篇
  2005年   88篇
  2004年   64篇
  2003年   58篇
  2002年   61篇
  2001年   63篇
  2000年   41篇
  1999年   34篇
  1998年   20篇
  1997年   23篇
  1996年   19篇
  1995年   21篇
  1994年   34篇
  1993年   15篇
  1992年   14篇
  1991年   15篇
  1986年   13篇
  1984年   14篇
  1981年   17篇
  1969年   14篇
  1968年   13篇
  1967年   16篇
  1966年   24篇
  1965年   29篇
  1964年   18篇
  1963年   26篇
  1962年   23篇
  1961年   31篇
  1960年   21篇
  1959年   21篇
  1958年   14篇
  1957年   25篇
  1956年   16篇
  1955年   16篇
排序方式: 共有2472条查询结果,搜索用时 15 毫秒
851.
Waste plastic (WP) and tall oil pitch (T), which are organic recycled industrial by-products, have been used as a binder with bitumen in stone mastic asphalt (SMA) and asphalt concrete (AC). We compared the exposure over one workday in 16 road pavers participating in a survey at four paving sites, using mixes of conventional asphalt (SMA, AC) or mixes containing waste material (SMA-WPT, AC-WPT). The concentrations of 11 aldehydes in air were 515 and 902 microg m(-3) at the SMA-WPT and AC-WPT worksites, being 3 and 13 times greater than at the corresponding worksites laying conventional asphalt. Resin acids (2-42 microg m(-3)), which are known sensitizers, were detected only during laying of AC-WPT. The emission levels (microg m(-3)) of total particulates (300-500), bitumen fumes (60-160), bitumen vapour (80-1120), naphthalene (0.59-1.2), phenanthrene (0.21-0.32), pyrene (<0.015-0.20), benzo(a)pyrene (<0.01) and the sum of 16 PAHs (polycyclic aromatic hydrocarbons, 1.28-2.00) were similar for conventional and WPT asphalts. The dermal deposition of 16 PAHs on exposure pads (on workers' wrist) was low in all pavers (0.7-3.5 ng cm(-2)). Eight OH-PAH biomarkers of naphthalene, phenanthrene and pyrene exposures were quantified in pre- and post-shift urine specimens. The post-shift concentrations (mean +/- SD, micromol mol(-1) creatinine) of 1- plus 2-naphthol; 1-,2-,3-,4- plus 9-phenanthrol; and 1-hydroxypyrene were, respectively, for asphalt workers: 18.1+/- 8.0, 2.41 +/- 0.71 and 0.66+/- 0.58 (smokers); 6.0+/- 2.3, 1.70+/- 0.72 and 0.27+/- 0.15 (non-smokers); WPT asphalt workers: 22.0+/- 9.2, 2.82+/- 1.11 and 0.76+/- 0.18 (smokers); 6.8+/- 2.6, 2.35+/- 0.69 and 0.46+/- 0.13 (non-smokers). The work-related uptake of PAHs was low in all pavers, although it was significantly greater in smokers than in non-smokers. The WPT asphalt workers complained of eye irritation and sore throat more than the pavers who had a much lower exposure to aldehydes and resin acids.  相似文献   
852.
For characterisation of landscapes in north-eastern Estoniaaffected by alkaline oil shale fly ash and cement dust the zonation-method based on average annual (C y) and short-termconcentrations of pollutants in the air was used, as well as on deposition loads of dust and Ca2+. In the overground layer of atmosphere the zones with different air pollution loads were distinguished. A comparative analysis of pollution zones characteristics and biomonitoring data revealed that for sensitive lichen the dangerous level of alkaline dust in the air, introducingthe degradation of Sphagnum sp. at the level of C y of dust 10–20 g m-3 and at 0.5–1 hr maximums 100–150 g m-3. For Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) this limited concentration (decline of growth parameters) of cement dust is correspondingly following: 30–50 g m-3 and 150–500 g m-3, in case of fly ash the limit level of C y amounting 100 g m-3. Daily deposition load of Ca2+ should not exceed approximately 4.5–15 mg m-2 for lichen; for conifers the harmful pollution load is higher – >22 mg m-2.  相似文献   
853.
Environmental Science and Pollution Research - This study estimated unbalanced panel data analysis to investigate the relationship among CO2 emissions, GDP, renewable and non-renewable energy...  相似文献   
854.
Introduction. Musculoskeletal symptoms related to using traditional computer workstations are common. Quantitative methods for measuring muscle stress and strain are needed to improve ergonomics of workstations. We hypothesize that infrared thermography (IRT) is suited for this purpose. Methods. This hypothesis was evaluated by estimating muscle activity in upright and traditional working postures with IRT and surface electromyography (sEMG). IRT and sEMG measurements were conducted in 14 female participants with both working postures. First, measurements with the traditional posture were performed. Later, participants had 1?month to adjust to the upright working posture before repeating the measurements. IRT images were acquired before and after a full working day, with sEMG recordings being conducted throughout the measurement days. Participants evaluated their neck pain severity using neck disability index (NDI) questionnaires before the first and after the second measurement day. Results. Spatial variation in upper back temperature was higher (p?=?0.008) when working in traditional posture and the upright working posture reduced (p?p?=?0.003) after working in the upright posture. Conclusion. IRT was found suitable for evaluating muscle activity and upright working posture to reduce the NDI and muscle activity in the upper back.  相似文献   
855.
Projections for the next 50 years predict a widespread distribution of hypoxic zones in the open and coastal ocean due to environmental and global changes. The Tidal Garonne River (SW France) has already experienced few episodic hypoxic events. However, predicted future climate and demographic changes suggest that summer hypoxia could become more severe and even permanent near the city of Bordeaux in the next few decades. A 3D model, which couples hydrodynamic, sediment transport, and biogeochemical processes, is applied to assess the impact of factors submitted to global and regional climate changes on oxygenation in the turbidity maximum zone (TMZ) of the Tidal Garonne River during low-discharge periods. The model simulates an intensification of summer hypoxia with an increase in temperature, a decrease in river flow or an increase in the local population, but not with sea level rise, which has a negligible impact on dissolved oxygen. Different scenarios were tested by combining these different factors according to the regional projections for 2050 and 2100. All the simulations showed a trend toward a spatial and temporal extension of summer hypoxia that needs to be considered by local water authorities to impose management strategies to protect the ecosystem.  相似文献   
856.
857.
Soil inventories of anthropogenic radionuclides were investigated in altitudinal transects in 2 French regions, Savoie and Montagne Noire. Rain was negligible in these 2 areas the days after the Chernobyl accident. Thus anthropogenic radionuclides are coming hypothetically only from Global Fallout following Atmospheric Nuclear Weapon Tests. This is confirmed by the isotopic signatures (238Pu/239+240Pu; 137Cs/239+240Pu; and 241Am/239+240Pu) close to Global Fallout value. In Savoie, a peat core age-dated by 210Pbex confirmed that the main part of deposition of anthropogenic radionuclides occurred during the late sixties and the early seventies. In agreement with previous studies, the anthropogenic radionuclide inventories are well correlated with the annual precipitations. However, this is the first time that a study investigates such a large panel of annual precipitation and therefore of anthropogenic radionuclide deposition. It seems that at high-altitude sites, deposition of artificial radionuclides was higher possibly due to orographic precipitations.  相似文献   
858.
859.
Concentrations of NO2, NO, and O3 from a rooftop monitoring station in Gothenburg, Sweden (2002–2006) were analysed to characterise NO2 pollution. [NO2] was shown to correlate strongly and non-linearly with [NO x ] (NO x ?=?NO?+?NO2), in line with observations in other cities. The [NO2] to [NO x ] fraction fell initially with increasing [NO x ]. At [NO x ] levels >200 ppb, the decline in [NO2]/[NO x ] with increasing [NO x ] levelled out and [NO2]/[NO x ] converged towards approximately 0.15–0.16, independent of [NO x ]. Data from a traffic route site showed the same pattern. This value of [NO2]/[NO x ] at high [NO x ] can be interpreted as the NO2 fraction of the NO x emissions from vehicle exhaust. Situations with high NO x pollution and minimum [NO2]/[NO x ] were always associated with [O3] close to zero. Plotting [Ox] (Ox?=?NO2?+?O3) vs. [NO x ] provided a strong linear correlation for situations dominated by local pollution ([NO]/[NO2]>1). The slope of the regression, a measure of the primary NO2 fraction in NO x emissions, was 0.13 during the day and 0.14 during the night. With stronger winds, the rooftop monitoring station became more similar, in terms of NO2 pollution, to a city street site and a traffic route site, although [NO2] was almost always higher at the street/traffic route locations. The EU standard for the annual average of [NO2] (40 μg m?3) was exceeded, while the hourly standard (200 μg m?3, not to be exceeded more than 18 times per year by 2010) was not exceeded at any of the sites.  相似文献   
860.
Understanding and managing ecosystems affected by several anthropogenic stressors require methods that enable analyzing the joint effects of different factors in one framework. Further, as scientific knowledge about natural systems is loaded with uncertainty, it is essential that analyses are based on a probabilistic approach. We describe in this article about building a Bayesian decision model, which includes three stressors present in the Gulf of Finland. The outcome of the integrative model is a set of probability distributions for future nutrient concentrations, herring stock biomass, and achieving the water quality targets set by HELCOM Baltic Sea Action Plan. These distributions can then be used to derive the probability of reaching the management targets for each alternative combination of management actions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号