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51.
People's dependence on firewood as a primary source of energy is causing serious deforestation problems in many developing countries. Reliable information on firewood consumption rates is needed to develop afforestation plans and to control deforestation. This study compares three methods used to determine firewood consumption in a Nepali village. Cultural and environmental factors that affect firewood consumption in the village are also examined.Theweight survey proved to be the most accurate method used. The less precisedaily recall andannual recall surveys overestimated actual firewood consumption by factors of 1.76 and 1.95, respectively. Overestimates are attributed to both physical and social factors. In view of the good agreement between daily and annual recall surveys, and the much greater ease of conducting the latter, annual recall surveys are recommended as the most practical method of monitoring firewood consumption rates. Validating the survey with occasional weighed measurements is suggested as a means of improving accuracy.  相似文献   
52.
Muramic acid (Mur) is found in bacterial peptidoglycan (PG) whereas 3-hydroxy fatty acids (3-OH FAs) are found in Gram-negative bacterial lipopolysaccharide (LPS). Thus Mur and 3-OH FAs serve as markers to assess bacterial levels in indoor air. An initial survey, in a school, demonstrated that the levels of dust, PG and LPS (pmol m(-3)) were each much higher in occupied rooms than in the same rooms when unoccupied. In each instance, the Mur content of dust was increased and the hydroxy fatty acid distribution changed similarly suggesting an alteration in the bacterial population. Here, findings are compared with results from two additional schools. Follow-up aerosol monitoring by particle size was also performed for the first time for all 3 schools. The particle size distribution was shown to be quite different in occupied versus unoccupied schoolrooms. Within individual classrooms, concentrations of airborne particles [greater-than-or-equal]0.8 [micro sign]m in diameter, and CO(2) were correlated. This suggests that the increased levels of larger particles are responsible for elevation of bacterial markers during occupation. Release of culturable and non-culturable bacteria or bacterial aggregates from children (e.g. from flaking skin) might explain this phenomenon.  相似文献   
53.
Self‐report measures of job stressors have been criticized for being too subjective, rendering relations with other variables inconclusive. The Factual Autonomy Scale (FAS) was developed to reduce subjectivity by careful choice of fact‐based items. Results of two studies showed that when compared to the Job Diagnostic Survey autonomy scale, the FAS demonstrated superior convergent validity with alternate sources (supervisors in Study 1 and coworkers in Study 2), and discriminant validity when correlated with the remaining JDS core characteristics subscales. In addition, the FAS was correlated to a lesser extent than the JDS autonomy scale with job satisfaction. Incumbent FAS scores and not JDS scores correlated significantly with job performance as assessed by supervisors. It is suggested that it is feasible to develop fact‐based items for scales of the work environment that reduce the degree of subjectivity of responses. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
54.
55.
During the 1950s and 1960s, reproductive failures and population declines were observed in fish-eating birds such as gulls, terns, cormorants, herons, and eagles in the Great Lakes. DDE-induced eggshell thinning contributed to these declines, but other factors such as embryo toxicity also were implicated. With reduced releases of many pollutants, reproduction recovered in some species. However, biomonitoring during the 1980s and 1990s indicates continuing effects at highly contaminated sites. Improved analytical techniques and bioassays have allowed the assessment of the total dioxin-like toxicity of complex mixtures of organochlorines (TCDD-equivalents). Developmental defects such as embryo mortality, deformities, and edema have been associated with dioxin-like PCBs in several avian species. Improved biochemical techniques have allowed the measurement of biomarkers that detect physiological alterations associated with contaminants. Specific biomarkers studied in Great Lakes birds include cytochrome P-450 monooxygenases, highly carboxylated porphyrins, thyroxine, vitamin A, and immune function. Reproductive and physiological alterations are associated with population-level effects in Caspian terns and bald eagles that feed on highly contaminated fish. Biomonitoring using biomarkers and population-level measures in fish-eating birds will continue to be important for assessing the effects of contaminants on the Great Lakes ecosystem.  相似文献   
56.
Few empirical works have examined the process through which CEO dispositions relate to organizational outcomes. In this study we examined the relationships between CEO values and organizational culture, and between organizational culture and firm performance. Data were collected from different sources (26 CEOs, 71 Senior Vice Presidents and 185 other organizational members), and include organizational financial performance data collected at two points in time. In support of our hypotheses, CEO self‐directive values were associated with innovation‐oriented cultures, security values were associated with bureaucratic cultures and benevolence values were related to supportive cultures. In turn, cultural dimensions showed differential associations with subsequent company sales growth, an index of organizational efficiency and assessments of employee satisfaction. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
57.
Warren C  Mackay D  Whelan M  Fox K 《Chemosphere》2007,68(7):1232-1244
It is useful to have available a variety of catchment-scale water quality models that range in complexity, spatial resolution and data requirements. In a previous paper [Warren, C., Mackay, D., Whelan, M., Fox, K., 2005. Mass balance modelling of contaminants in river basins: a flexible matrix approach. Chemosphere 61, 1458-1467] a series of simple to intermediately complex mass balance models was presented which can be used for tiered exposure assessments in river basins. The connectivity of the segments is expressed using a matrix that permits flexibility in application, enabling the model to be re-segmented and applied to different catchments as required. In this paper, the intermediate models, QWASI matrix-rate constant (QMX-R) and QWASI matrix-fugacity (QMX-F) are used to estimate concentrations of linear alkylbenzene sulfonates (LAS) in the rivers Aire and Calder, UK, and of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the Fraser River basin, Canada. The results compare satisfactorily with monitoring data, suggesting that these QWASI-based models for exposure and risk assessment may be applicable under data-limited conditions. The use of QWASI-based models for regulatory purposes in an evaluative river system is also discussed with reference to assessments of para-dichlorobenzene (pDCB), trichloroethylene (TCE), bis(2-ethylhexyl) phthalate (DEHP) and toluene. It is shown that multi-media QWASI model predictions can be usefully depicted graphically on chemical space diagrams and used to highlight regions in which advection, partitioning to sediments and volatilization may be important determinants of chemical fate in river systems.  相似文献   
58.
A new generic approach for estimating chemical concentrations in rivers at catchment and national scales is presented. Domestic chemical loads in waste water are estimated using gridded population data. River flows are estimated by combining predicted runoff with topographically derived flow direction. Regional scale exposure is characterised by two summary statistics: PEC(works), the average concentration immediately downstream of emission points, and, PEC(area), the catchment-average chemical concentration. The method was applied to boron at national (England and Wales) and catchment (Aire-Calder) scales. Predicted concentrations were within 50% of measured mean values in the Aire-Calder catchment and in agreement with results from the GREAT-ER model. The concentration grids generated provide a picture of the spatial distribution of expected chemical concentrations at various scales, and can be used to identify areas of potentially high risk.  相似文献   
59.
The response of shrubs of Larrea tridentata (DEC) Coville (creosotebush) exposed to sulphur dioxide (SO(2)) was evaluated using in situ plants of the Majove Desert. Larrea was exposed to acute levels of 0.3 to 2.0 microl litre(-1) SO(2) for periods up to 13 days using field chambers or an open-air fumigation system. Plants exposed in the spring exhibited considerable leaf injury (necrosis and defoliation) when exposed to 2.0 microl litre(-1) SO(2), and in the autumn had leaf injury when exposed to >0.4microl litre(-1) SO(2). Injured plants had higher transpiration rates, less negative water pressure potentials, and/or lower photosynthetic rates than control plants. It is likely that Larrea would not be injured by the typically low SO(2) concentrations and dry environmental conditions of the Mojave Desert. However, if injury were to occur, it would be accompanied by changes in plant-water relations and photosynthesis, followed by recovery after the SO(2) stress was removed.  相似文献   
60.
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