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271.
It is well known that explosive mixtures can exist at temperatures below the flash point (FP). Experiments show that the difference between the FP and the lower explosion point (LEP) may be up to 15 K and in some special cases even more. Consequently, an industrial process even running a few Kelvin below the FP may operate in an explosive vapour/air-atmosphere. Operating at temperatures below the LEP gives sufficient safety. Calculated LEPs are discussed and compared with experimental results.  相似文献   
272.
Input–output modeling and cluster analysis are used to assess the impacts of oil consumption industries on environmental quality and inter-industry relationships in Taiwan. Results indicate that fuel oil has the greatest impact on the environment. The transportation sector has grown rapidly with high energy intensity and severe pollution emission in Taiwan. Also, power generation, other industrial chemicals, paper products, non-metallic mineral products, petro-chemical materials, rubber products, cement and textiles are identified as the most significant industries causing serious pollution problems in Taiwan. Results of inter-industry linkages confirm that investment of the above-mentioned industries should be adjusted to better energy efficiency, environmental quality and economic bases. This study indicates that energy policy should integrate environmental policy, in addition to assuring energy and economical gains.  相似文献   
273.
Electrosynthesis at pH 9, 12, and 11 of -carrageenan–gelatin complexes from electrolytes containing the components at proportions varying from 1:5 to 5:1 provided complexes in the composition varying in a range from 1:10 to 1:1.8. Components were bound mainly electrostatically, although partial insolubility of complexes in 7 M aqueous urea pointed to a part of the complexes bound covalently. None of the performed tests except solubility could confirm formation of covalent complexes. The complexation of -carrageenan to gelatin significantly increased the thermal stability of carrageenan, whereas the thermal stability of gelatin increased rather insignificantly.  相似文献   
274.
We investigated differences in vegetation composition and dynamics for two globally rare ecosystems, bracken–grasslands and northern–dry forests of northern Wisconsin. These ecosystems commonly have been viewed as degraded pine barrens. Bracken–grasslands contained a high dominance of exotic species, low native richness, and no obvious prairie species, suggesting logging-era anthropogenic origins. Differences in cover for common plants among ecosystems were examined using Mann-Whitney U tests of equivalence. Cover of all 8 graminoid species, 4 of 5 Ericaceae and Myricaceae species, and 10 of 17 species of forbs were significantly different between ecosystems. Vegetation changes over a 4-year period were examined through detrended correspondence analysis (DCA) and analysis of variance (ANOVA) repeated measures. DCA analyses of community composition failed to detect significant temporal trends within individual management units, although differences were apparent between ecosystems, regardless of sample year. In addition, no apparent patterns could be detected between years when comparing dominant individual species to management history (prescribed fire). This is contrary to what would be expected for a degraded pine barrens and questions the efficacy of using repeated prescribed fire as a management tool in bracken–grasslands. Methods for conservation and restoration of xeric ecosystems of northern Wisconsin have historically relied heavily on single species (e.g., sharp-tailed grouse) wildlife models, without full consideration of other factors. We suggest that stakeholders involved in these restoration projects examine historic processes and reference conditions prior to formulating management goals. Greater attention to the differentiation and individual management needs of pine barrens, northern–dry forests, and bracken–grasslands is needed.  相似文献   
275.
《组织行为杂志》2017,38(4):558-591
There are competing theoretical rationales and mechanisms used to explain the relation between leadership behaviors (e.g., consideration, initiating structure, contingent rewards, and transformational leadership) and follower performance (e.g., task performance and organizational citizenship behaviors). We conducted two studies to critically examine and clarify the leadership behaviors–follower performance relation by pitting the various theoretical rationales and mechanisms against each other. We first engaged in deductive (Study 1) and then inductive (Study 2) theorizing and relied upon 35 meta‐analyses involving 3327 primary‐level studies and 930 349 observations as input for meta‐analytic structural equation modeling. Results of our dual deductive–inductive approach revealed an unexpected yet surprisingly consistent explanation for why leadership behaviors affect follower performance. Specifically, leader–member exchange is a mediating mechanism that was empirically determined to be involved in the largest indirect relations between the four major leadership behaviors and follower performance. This result represents a departure from current conceptualizations and points to a common underlying mechanism that parsimoniously explains how leadership behaviors relate to follower performance. Also, results lead to a shift in terms of recommendations for what leaders should focus on to bring about improved follower performance. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
276.
《组织行为杂志》2017,38(8):1246-1259
Prior research suggests that leaders' social cynicism can undermine important follower outcomes such as followers' motivation and performance. However, these studies have exclusively focused on leaders' social cynicism and neglected that followers' views on the social world might also influence the leadership process. On the basis of theories of social beliefs and person–supervisor fit, we offer an integrative perspective and predict that it is the congruence between leaders' and followers' social cynicism that shapes leadership dynamics. Data from 116 leader–follower dyads from a broad range of organizations and industries support our model: Polynomial regression and response surface analyses show significant congruence effects of leaders' and followers' social cynicism on followers' extra‐role behaviors and followers' proactive work behaviors. These positive effects of congruence on follower outcomes are transmitted by leader–member exchange quality. Finally, congruence effects are stronger when leaders' and followers' social cynicism is low rather than high. Overall, our study suggests that it is the correspondence between leaders' and followers' social cynicism that influences followers' leader–member exchange, extra‐role, and proactive behavior. We discuss the theoretical and practical implications of these findings for designing functional leader–follower dyads in organizations.  相似文献   
277.
Lowland rice fields constitute a semi aquatic environment, which is potentially suitable for fish production. Little is known about the effect of fish on greenhouse gas emissions from integrated rice–fish systems. An experiment was carried out at the Bangladesh Agricultural University to assess the effect of the stocking of fish on methane emissions from rice fields. Common carp, Cyprinus carpio L., and Nile Tilapia, Oreochromis niloticus (L.) were stocked in a mixed culture and subjected to three different input regimes: (1) urea fertilization according to the recommendation of the Bangladesh Rice Research Institute (BRRI), (2) supplementary feeding at 2 × maintenance level and (3) an elevated feeding schedule where 4 × maintenance level was fed initially and 2 × maintenance level towards the end of the growth period. Rice only with urea fertilization according to BRRI-recommendation was included as the control. The presence of fish increased methane emissions in all three rice–fish treatments. Average emission over the cropping season was 34, 37, and 32 mg m−2 h−1 in the rice–fish treatments, respectively, and 20 mg m−2 h−1 in rice only. Apart from an increase in methane emission, a significant drop (p < 0.05) in floodwater pH and dissolved oxygen concentration was observed in the rice–fish plots. Both parameters were the lowest in the treatment where a higher feeding rate was provided. Due to the fish activity, floodwater in the rice–fish treatments was more turbid, as reflected in higher particulate inorganic matter (PIOM). An elevated level of dissolved methane was observed in the floodwater of the feed supplemented rice–fish plots. Methane emissions showed negative correlation with morning and afternoon pH of the floodwater (r = −0.46; r = −0.56, p < 0.001) and morning and afternoon dissolved oxygen level (r = −0.53; r = −0.46, p < 0.001). Positive correlations were recorded between morning and afternoon floodwater temperature (r = 0.49; r = 0.44, p < 0.001) and with air temperature (r = 0.54, p < 0.001). The results suggest that the stocking of fish has an increasing effect on methane emissions from rice fields.  相似文献   
278.
Carbon dioxide was photo-catalytically reduced to produce formic acid in an aqueous solution using visible light irradiation. Titania and zinc-phthalocyanine (ZnPc)-loaded titania were synthesized by a sol–gel method and in situ chemical synthesis technique. The photo-catalytic reactions were conducted in a Pyrex reactor with a visible light irradiating. XRD and DRS revealed that ZnPc was on the TiO2 surface. The optimum technique was in situ chemical synthesis and the optimum amount of ZnPc loading was 1.0 wt.% for the highest dispersion among catalysts. The formic acid yield of 1.0 wt.% in situ ZnPc/TiO2 was 978.6 μmol/g catalyst following 10 h of visible light illumination and the conversion was 0.37%. The yield was higher than those of sol–gel TiO2 and ZnPc/BH-1, whose yields were 321.0 and 756.2 μmol/g catalyst, respectively. Experimental results indicated that the formic acid yield was significantly increased by loading ZnPc. ZnPc has a higher selectivity than metal catalysts for the reduction of CO2. The photo-catalytic efficiency of ZnPc/TiO2 was markedly increased because of the lowering re-combination probability for hole–electron pairs.  相似文献   
279.
Environmental supply chain dynamics   总被引:8,自引:0,他引:8  
This paper investigates the circumstances under which “environmental supply chain dynamics” (ESCD) emerge. ESCD are a phenomenon where environmental innovations diffuse from a customer firm to a supplier firm. Its relevance is based on the argument that systemic approaches are needed to understand the environmental implications of industrial systems, of which supply chains are a key component. Furthermore, buyer–supplier relationships play a critical role in the decision-making processes of most suppliers, which in turn has the potential to stimulate environmental change within the supply chain. Based on case studies in the British and Japanese food retail sector and the British aerospace industry, it will be shown that ESCD emerge if there is a channel leader with sufficient channel power over their suppliers, technical competencies, and are themselves under specific environmental pressure.  相似文献   
280.
Lead contamination in the roadside soils of Slovenia   总被引:5,自引:0,他引:5  
The level of lead contamination along the roadway Ljubljana to Zagreb was established in 184 soil samples. The samples were taken from two depths (0–5cm and 15–20cm) and at different distances from the roadway. The influence of terrain morphology, prevailing winds, geological parent material and type of vegetation was estimated. Heavy traffic is confirmed as main source of lead contamination (average enrichment factor 17) in soils. The highest lead accumulation is localised in the top soil layer and within 10m from the roadside. Contamination with lead is more pronounced in soil samples from cuttings and slopes than in soils from plains and mounds. Soils derived from carbonate rocks contain higher lead concentration than those derived from other parent material.  相似文献   
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