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   1107篇
  免费   8篇
  国内免费   13篇
安全科学   27篇
废物处理   53篇
环保管理   134篇
综合类   170篇
基础理论   217篇
污染及防治   369篇
评价与监测   95篇
社会与环境   57篇
灾害及防治   6篇
  2023年   13篇
  2022年   32篇
  2021年   31篇
  2020年   24篇
  2019年   15篇
  2018年   33篇
  2017年   41篇
  2016年   50篇
  2015年   40篇
  2014年   61篇
  2013年   113篇
  2012年   69篇
  2011年   85篇
  2010年   46篇
  2009年   51篇
  2008年   77篇
  2007年   64篇
  2006年   52篇
  2005年   48篇
  2004年   27篇
  2003年   35篇
  2002年   18篇
  2001年   13篇
  2000年   9篇
  1999年   6篇
  1998年   7篇
  1997年   6篇
  1996年   10篇
  1995年   3篇
  1994年   8篇
  1993年   3篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1987年   3篇
  1986年   2篇
  1984年   2篇
  1983年   2篇
  1982年   3篇
  1981年   4篇
  1978年   1篇
  1976年   3篇
  1974年   1篇
  1973年   1篇
  1968年   1篇
  1967年   2篇
  1954年   1篇
排序方式: 共有1128条查询结果,搜索用时 15 毫秒
941.
Water quality has degraded dramatically in the Chocancharava River (Río Cuarto, Córdoba, Argentina) due to point and non-point sources. This paper aims to assess spatial and temporal variations of physical and chemical parameters of the river. Six sampling sites and six sampling campaigns were developed. During the period 2007–2008, wet and dry seasons were included. A statistical analysis was carried out with 23 physical and chemical variables. Then, a new statistical analysis was carried out including the Riparian Corridors Quality Index and the physical and chemical variables (24 variables). Considering a multivariate system, analysis of variance, principal component analysis and cluster analysis were used. From the statistical analysis, the river was divided into two zones with different degrees of contamination. The most polluted zone is due to pollution inputs of urban, industrial and agricultural sources. This area showed a remarkable deterioration in water quality, mainly due to wastewater discharges. According to Riparian Quality, better results were found in sections of poor water quality, due to the fact that the river bank forest was less degraded downstream of the sewage discharge.  相似文献   
942.
The Mondego River estuary demonstrates signs of pollution, but the levels of endocrine disrupting compounds (EDCs), such as the natural (17β-estradiol and estrone) and pharmaceutical (17α-ethynylestradiol) estrogens, xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol, and their mono- and diethoxylates and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, and genistein), and sitosterol were either poorly or never measured in this area. Thus, to conclude about the influx of EDCs in this estuary, water samples were taken every 2 months, during 1 year (2010) in low tide, at eight sites distributed along the estuary. Water samples (1 L) were preconcentrated in the Oasis HLB cartridges and cleaned in silica cartridges before their analysis by GC-MS. In summer, potentially hazardous amounts of estrogens (≈26 ng L?1), alkylphenols (≈11.5 μg L?1), alkylphenolethoxylates (≈13 μg L?1), and phytoestrogens (≈5.6 μg L?1) were measured. These data suggest that changes in the hydrodynamics of the estuary coupled with the increase of water temperatures interfere with the amount of EDCs in the water. Complementary physicochemical parameters also point to high levels of anthropogenic pollution in this area. Globally, the estrogenic load, expressed in ethynylestradiol equivalents, attained 71.8 ng L?1 demonstrating that, all together, the measured EDCs pose important health risks for both biota and humans.  相似文献   
943.
944.
945.

Introduction

This article describes one experiment that studied the influence of Daytime Running Lamps (DRL) on pedestrian detection of turn indicators.

Method

An experimental device including one DRL and one turn indicator was used in order to determine Visual Reaction Times (VRT) of 148 observers in different situations involving turn indicator activation. Such situations were combinations of three main variables: color of DRL, separation between DRL and Turn Indicator, and observation angle.

Results

Significant changes in VRT were found depending on the configurations above, especially the observation angle and the color of DRL. This second result demonstrates that amber DRLs inhibit the detection of Turn Indicators.

Impact on industry

One of the main targets of this paper is to recommend that carmakers introduce only white DRLs on new vehicles. We also intend to advise regulatory bodies working on automotive regulation about the consequences of allowing amber DRLs and also about the danger of introducing constrains on the distance between DRL and Turn Indicator without further experimental evidences.  相似文献   
946.
This article introduces a management tool for salmon farming, with a scope in the local sustainability of salmon aquaculture of the Aysen Fjord, Chilean Patagonia. Based on Integrated Coastal Zone Management (ICZM) principles, the tool combines a large 3-level nested hydrodynamic model, a particle tracking module and a GIS application into an assessment tool for particulate waste dispersal of salmon farming activities. The model offers an open source alternative to particulate waste modeling and evaluation, contributing with valuable information for local decision makers in the process of locating new facilities and monitoring stations.  相似文献   
947.
Environmental Science and Pollution Research - Making good environmental damage caused by industrial accidents and restoring impaired ecosystems may be associated with high costs. The European...  相似文献   
948.
Introduction. The effect of different kinds of work on the psychosocial assessment of workers under the same management and organizational environment is investigated. Methods. A voluntary assessment in a utility company was carried out using the short version of the Copenhagen psychosocial questionnaire (CoPsoQ) on two occasions, 1.5 years apart. Initially, 25 office workers (11 men and 14 women) participated, while 14 of those workers (8 women and 6 men) participated in the second assessment together with 32 field workers. The sewage, water treatment and maintenance workers, totaling 32 men, also participated in a field ergonomics assessment using the Washington State Department of Labor and Industries field work ergonomic checklist. Results. The longitudinal outlook was fairly stable, with sustained severe scores in many CoPsoQ subscales and intensification of severity of workers’ control over work and esteem for men. A significantly higher esteem score resulted for field rather than office workers. Workers subjected to foul odors showed similar severity of psychosocial factors. Discussion. For most psychosocial dimensions, the organizational design and management system in place, as well as the overall cultural environment in which it operates, create a much stronger and more decisive impact than job-specific factors.  相似文献   
949.
In this research tannic acid was used to prepare soy-based adhesives for making plywood and fiber board. The different resin formulations were analyzed by Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and its derivative as a function of temperature (DTG) and Fourier Transform Infra-red (FTIR) spectroscopy. The results showed that the addition of tannic acid to soy-based adhesive decreased soy-based adhesive viscosity and its pH. The DSC analysis showed that the denaturation temperature of soy-based adhesives decrease by adding tannic acid. The TGA and DTG curves showed that the thermal degradation of soy flour starts above 146 °C. The FTIR spectroscopy results also showed that the soy flour amino acids appeared to react well with tannic acid. Furthermore, delamination and shear strength test results showed the good water resistance of plywood bonded with soy-based tannic acid-modified adhesive. The mechanical and physical properties such as MOR, MOE, IB, and water resistance of fiberboard were improved, by adding tannic acid to the soy-based adhesive.  相似文献   
950.
Continuous measurements of the CO2 concentration were repeatedly carried out from 1996 to 2007 between Italy and New Zealand by means of a Siemens Ultramat 5E analyzer assembled for shipboard use. Along the ship routes discrete air samples were collected from 1998 to 2005 using four-litre Pyrex flasks. The δ13C of the CO2 from the flask air samples was measured according to well-established techniques. The decadal changes of these two variables can now be evaluated from these results. Large variations of the CO2 concentration were normally recorded in the Mediterranean and the Red Sea. Completely different trends of the CO2 concentration were observed in the Red Sea (30° N to about 13° N) between 2007 (a marked southward decrease) and 2005 and 2003 when a marked southward increase is apparent, at least between 23° and 13° N. A further difference among different expeditions is related to the decrease or increase of the CO2 concentration in the Gulf of Aden. The backward trajectories of the air masses help to explain, at least partially, these differences. In the Indian Ocean and Southern Ocean a decrease of a few ppmv of the CO2 concentration takes place from Cape Guardafui (Northern Somaliland) to southern New Zealand, particularly during 2005 and 2007. The yearly rate of increase of the CO2 concentration between 1996 and 2007 for the Indian Ocean is of about 1.9 ppmv yr?1, in excellent agreement with the NOAA/CMDL measurements carried out during the same period at Mahé Isld. (Indian Ocean) and Cape Grim (Tasmania). The δ13C results obtained from the CO2 of flask samples collected in the Mediterranean show the effect of anthropogenic emissions, though this is considerably smaller than expected. This inconsistency may be related to the large terrestrial biospheric sink of CO2 in the Northern Hemisphere. The results obtained from the Red Sea are quite variable through time and space, particularly in its southern section; their interpretation is not easy. The Indian Ocean and the Southern Ocean show rather homogeneous δ13C results even though a variable carbon isotope shift can be calculated from period/cruise to period/cruise. In the case of the Indian Ocean the mean δ13C value from the flask air samples collected in 2005 is ?8.29‰ and the calculated rate of the carbon isotope shift between 1998 and 2005 is ?0.034‰ yr?1, considerably larger than that calculated at the closest NOAA station (Mahé Isld.) of ?0.026‰ yr?1. This discrepancy may be, at least partially, caused by the small number of measurements carried out at sea. However, the atmosphere over the Indian Ocean is less affected by anthropogenic emissions than in other areas.  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