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171.
This research examined whether trainee demographics and pre‐training competence predicted participation in voluntary diversity training. Results indicate that demographic variables had no impact on interest in training (Study One) or on actual training participation (Study Two). However, pre‐training competence levels had a positive effect on both outcomes. More competent trainees expressed more interest in additional training (Study One) and were more likely to attend a voluntary training session (Study Two). The authors suggest that trainees with low competence in the diversity domain are unaware of their low competence levels and therefore are not motivated to participate in training programs designed to increase diversity competence. Implications of these findings for organizations offering voluntary diversity training are discussed. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
172.
It is difficult to make general recommendations that apply to all ecosystems. There is still a relative dearth of studies that allow the manager or visitor to come up with specific practices that are the best for their area. The preferred method of disposal remains to dig a small hole (cat hole) and bury the waste. Other site specific methods are also discussed. Treatment of drinking water has become standard practice for most backcountry travel. With such treatment, there is little evidence currently to suggest that the health hazard to humans is great enough to impose further regulation in areas currently using cat holes.  相似文献   
173.
Although radon can be present within buildings at sufficient levels to pose a health risk, levels can be reduced relatively easily. Recent studies on a group of radon-remediated homes, based on assessment of collective population-average risk coefficients, have estimated the benefits and cost effectiveness accruing from remediation and have confirmed that domestic remediation in UK radon Affected Areas would result in significantly reduced cancer risks to the population in those areas. Although the population-average approach used hitherto has applied occupancy and lung-cancer risk factors, these are potentially misleading in assessing discrete populations. The study reported here uses the recently developed European Community Radon Software (ECRS) to quantify individual risks in a sample of householders who remediated their homes following indications that radon levels exceeded the action level. The study proceeds from population-averaged to 'individual risk' evaluation, successfully comparing individual and collective risk assessments, and demonstrates that those who remediate are not representative of the general population. Health benefits accruing from remediation are three times lower than expected, largely because remediators are older, live in smaller households, and smoke less than the population average, leading to the conclusion that the current strategy employed in the UK is failing to target those most at risk.  相似文献   
174.
175.
The effects of the aflatoxins on ATPase activities in mouse and rat tissues were investigated in vitro. The hepatic oligomycin-sensitive (O.S.) Mg++ ATPase was inhibited significantly. The order of inhibition was G1 greater than B1 greater than G2 greater than B2. Mouse O.S. Mg++ ATPase was more sensitive than the corresponding rat enzyme. The oligomycin-insensitive (O.I.) Mg++ ATPase activities in rat and mouse liver were not altered. Although aflatoxins G1 and B1 were more potent inhibitors of hepatic O.S. Mg++ ATPase, no concentration-response was observed, whereas aflatoxins G2 and B2 inhibited enzyme activity in a concentration-dependent manner. Spectral analysis of aflatoxin G1 solutions suggested that solubility was not related to the observed effects. In addition, the effects of aflatoxin B1 and G1 on mouse brain microsomal Na+-K+ ATPase were examined. Although aflatoxin B1 was more potent that G1, both mycotoxins significantly inhibited enzyme activity in a concentration-dependent fashion.  相似文献   
176.
An investigation of the mechanisms of detoxication of copper and zinc by the oyster Ostrea edulis (L) has been carried out using naturally occurring green-sick (contaminated by copper) and unpolluted oysters. Electron microprobe X-ray analysis of tissues in the electron microscope gives direct evidence for the structural compartmentation of copper and zinc in separate, specific, granular amoebocytes. The metals are immobilized in membrane-limited vesicles as different chemical compounds, copper being associated with sulphur and zinc with phosphorus. Chemical analyses of serum and tissues of normal and green-sick oysters indicate that (a) Cu and Zn are accumulated independently, (b) the Cu and Zn in the serum, while higher than in the surrounding sea water, are maintained at a 10-fold smaller level than the tissues, (c) toxicity is reduced by active uptake from the serum into granular amoebocytes, where it is further reduced by compartmentation in membrane-limited vesicles. It is calculated that the individual cell types may contain as much as 13,000 ppm Cu and 25,000 ppm Zn.  相似文献   
177.
Methyl iodide (MeI) is a promising alternative to methyl bromide in soil fumigation. The pest-control efficacy and ground water contamination risks of MeI as a fumigant are highly related to its gas-phase distribution and leaching after soil application. In this study, the distribution and leaching of MeI in soil following shank injection and subsurface drip application were investigated. Methyl iodide (200 kg ha(-1)) was directly injected or drip-applied at a 20-cm depth into Arlington sandy loam (coarse-loamy, mixed, thermic Haplic Durixeralfs) columns (12-cm i.d., 70-cm height) tarped with virtually impermeable film. Concentration profiles of MeI in the soil air were monitored for 7 d. Methyl iodide diffused rapidly after soil application, and reached a 70-cm depth within 2 h. Relative to shank injection, drip application inhibited diffusion, resulting in significantly lower concentration profiles in the soil air. Seven days after MeI application, fumigated soil was uncapped, aerated for 7 d, and leached with water. Leaching of MeI was significant from the soil columns under both application methods, with concentrations of >10 mug L(-1) in the early leachate. The leaching was greater following shank injection than drip application, with an overall potential of 33 g ha(-1) for shank injection and 19 g ha(-1) for drip application. Persistent residues of MeI remaining in soils after leaching were 50 to 240 ng kg(-1), and the contents were slightly higher following shank injection than drip application. The results suggest that fumigation with MeI may pose a risk of ground water contamination in vulnerable areas.  相似文献   
178.
An investigation of radon levels in the caves of Creswell Crags, Derbyshire, an important Site of Special Scientific Interest (SSSI) shows that the Lower Magnesian Limestone (Permian) caves have moderate to raised radon gas levels (27-7800 Bq m(-3)) which generally increase with increasing distance into the caves from the entrance regions. This feature is partly explained in terms of cave ventilation and topography. While these levels are generally below the Action Level in the workplace (400 Bq m(-3) in the UK), they are above the Action Level for domestic properties (200 Bq m(-3)). Creswell Crags has approximately 40,000 visitors per year and therefore a quantification of effective dose is important for both visitors and guides to the Robin Hood show cave. Due to short exposure times the dose received by visitors is low (0.0016 mSv/visit) and regulations concerning exposure are not contravened. Similarly, the dose received by guides is fairly low (0.4 mSv/annum) due in part to current working practice. However, the risk to researchers entering the more inaccessible areas of the cave system is higher (0.06 mSv/visit). This survey also investigated the effect of seasonal variations on recorded radon concentration. From this work summer to winter ratios of between 1.1 and 9.51 were determined for different locations within the largest cave system.  相似文献   
179.
The effects of livestock grazing on selected riparian and stream attributes, water chemistry, and algal biomass were investigated over a two-year period using livestock enclosures and by completing stream surveys in the Cypress Hills grassland plateau, Alberta, Canada. Livestock enclosure experiments, partially replicated in three streams, comprised four treatments: (1) early season livestock grazing (June–August), (2) late season livestock grazing (August–September), (3) all season grazing (June–September), and (4) livestock absent controls. Livestock grazing significantly decreased streambank stability, biomass of riparian vegetation, and the extent to which aquatic vegetation covered the stream channels compared with livestock-absent controls. Water quality comparisons indicated significant differences among the four livestock grazing treatments in Battle and Graburn creeks but not in Nine Mile Creek. In Graburn Creek, the concentration of total phosphorus in the all-season livestock grazing treatment was significantly higher than that in the livestock-absent control, and the early season and late season grazing treatments. Concentrations of soluble reactive phosphorus in the all-season livestock grazing treatment also exceeded that in livestock-absent control. In contrast, differences in water quality variables in the remaining 22 comparisons (i.e., 22 of the total 24 comparisons) were minor even when differences were statistically significant. Effects of livestock grazing on algal biomass were variable, and there was no consistent pattern among creeks. At the watershed scale, spatial variation in algal biomass was related (P < 0.05) with concentrations of NO2 + NO3 and soluble reactive phosphorus in two of the four study creeks. Nutrient diffusing substrata experiments showed that algal communities were either nitrogen-limited or not limited by nutrients, depending on stream and season.  相似文献   
180.
The study was designed to determine seasonal differences in personal exposures to respirable suspended particles (RSP) and environmental tobacco smoke (ETS) for nonsmokers in Bremen, Germany. The subjects were office workers, either living and working in smoking locations or living and working in nonsmoking locations. One hundred and twenty four randomly selected nonsmoking subjects collected air samples close to their breathing zone by wearing personal monitors for 24 h or, in some cases, for 7-day periods during the winter of 1999. The investigation was repeated in the summer with 126 subjects, comprised of as many of the studied winter population (89 subjects) as possible. Saliva cotinine analyses were undertaken to verify the nonsmoking status of the subjects. Subjects wore one personal monitor while at work and one while away from the workplace on weekdays, and a third monitor at the weekend. Collected air samples were analysed for RSP, nicotine, 3-ethenylpyridine (3-EP) and ETS particles. The latter were estimated using ultraviolet absorbance (UVPM), fluorescence (FPM) and solanesol (SolPM) measurements. ETS exposure was consistently higher in the winter than in the summer, this pattern being particularly evident for subjects both living and working with smokers. The highest median 24-h time weighted average (TWA) concentrations of ETS particles (SolPM, 25 microg m(-3)) and nicotine (1.3 microg m(-3)) were recorded for subjects performing weekday monitoring during the winter. These were significantly higher than equivalent levels of ETS particles (SolPM, 2.4 microg m(-3)) and nicotine (0.26 microg m(-3)) determined during the summer. There were no appreciable differences between winter and summer percent workplace contributions to median TWA ETS particle and nicotine weekday concentrations, the workplace in Bremen, in general, contributing between 35% and 61% of reported median concentrations. Workers, on average, spent one-third of their time at work during a weekday, indicating that concentrations were either comparable or higher in the workplace than in the home and other locations outside the workplace. Median 24-h weekend ETS particle and nicotine concentrations for smoking locations were not significantly different from equivalent weekday levels during the winter, but were significantly lower during the summer. Based upon median 24-h TWA SolPM and nicotine concentrations for the winter, extrapolated to 1 year's ETS exposure, those subjects both living and working in smoking locations (the most highly exposed group) would potentially inhale 13 cigarette equivalents/year (CEs/y). However, based on a similar extrapolation of summer measurements, the same group of subjects would potentially inhale between 1.3 and 1.9 CEs/y. The most highly exposed subjects in this study, based upon 90th percentile concentrations for those both living and working in smoking locations during the winter, would potentially inhale up to 67 CEs/y in the winter and up to 22 CEs/y in the summer. This clearly demonstrates that seasonal effects should be taken into account in the design and interpretation of ETS exposure studies. Air sampling over a 7-day period was shown to be technically feasible, and subsequent RSP, ETS particle and nicotine levels determined by 7-day monitoring were not found to be significantly different from equivalent levels determined by 24-h monitoring. However, the longer sampling period resulted in the collection of an increased quantity of analytes, which improved the limits of quantitation (LOQ) and allowed a more accurate determination of low level ETS exposure. This was reflected by a reduced percentage of data falling below the LOQ for 7-day monitoring compared with 24-h monitoring. The use of a liquid chromatographic method with tandem mass spectrometric detection for saliva cotinine measurement afforded a greatly improved LOQ and greater accuracy at low concentrations compared with the radioimmunoassay (RIA) method used in previous studies by these authors. In this study, 17 subjects out of 180 tested (9.4%) were found to have saliva cotinine levels exceeding the selected threshold of 25 ng ml(-1) used to discriminate between smokers and nonsmokers.  相似文献   
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