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151.
The effect of selenium on the vegetative reproduction of cultured Lemna minor was investigated. Cultures were grown for 28 days at a temperature of 23 ± 3°C and under a constant (24 h) light cycle. Growth was monitored every seven days. The growth of L. minor was inhibited at high concentrations (>5mg/L [Se]), but stimulated at low concentrations (0.2—2mg/L [Se]). This stimulation of growth at low selenium concentrations has significant implications for the use of selenium enriched superphosphate fertilisers on selenium deficient pastures. 相似文献
152.
Edouard Kraffe Réjean Tremblay Sonia Belvin Jeqn-René LeCoz Yanic Marty Helga Guderley 《Marine Biology》2008,156(1):25-38
In scallops, gametogenesis and spawning can diminish the metabolic capacities of the adductor muscle and reduce escape response
performance. To evaluate potential mechanisms underlying this compromise between reproductive investment and escape response,
we examined the impact of reproductive stage (pre-spawned, spawned and reproductive quiescent) of the giant scallop, Placopecten magellanicus, on behavioural (i.e., escape responses), physiological (i.e., standard metabolic rates and metabolic rates after complete
fatigue) and mitochondrial capacities (i.e., oxidative rates) and composition. Escape responses changed markedly with reproductive
investment, with spawned scallops making fewer claps and having shorter responses than pre-spawned or reproductive-quiescent
animals. After recuperation, spawned scallops also recovered a lower proportion of their initial escape response. Scallop
metabolic rate after complete fatigue (VO2max) did not vary significantly with reproductive stage whereas standard metabolic rate (VO2min) was higher in spawned scallops. Thus spawned scallops had the highest maintenance requirements (VO2min/VO2max). Maximal capacities for glutamate oxidation by muscle mitochondria did not change with reproductive stage although levels
of ANT and cytochromes as well as cytochrome C oxidase (CCO) activity did. Total mitochondrial phospholipids, sterols and the proportion of phospholipid classes differed
only slightly between reproductive stages. Few modifications were detected in the fatty acid (FA) composition of the phospholipid
classes except in cardiolipin (CL). In this class, pre-spawned and spawned scallops had fairly high proportions of 20:5n-3
whereas this FA in reproductive-quiescent scallops was threefold lower and 22:6n-3 was significantly higher. These changes
paralleled the increases in CCO activity and suggest an important role of CL on the modifications of CCO activity in scallops.
However, mitochondrial properties could not explain the decreased recuperation ability from exhausting exercise in spawned
scallops. Shifts in maintenance requirements (VO2min/VO2max) and aerobic scope (VO2max − VO2min) provided the best explanation for the impact of reproduction on escape response performance. 相似文献
153.
Sonia Akter Roy Brouwer Saria Choudhury Salina Aziz 《Mitigation and Adaptation Strategies for Global Change》2009,14(3):215-229
The study aims to assess the commercial viability of a potential crop insurance market in Bangladesh. In a large scale household
survey, agricultural farm households were asked for their preferences for a hypothetical crop insurance scheme using double
bounded (DB) contingent valuation (CV) method. Both revenue and production cost based indemnity payment approaches were applied
to assess the commercial viability of a crop insurance program assuming a partner-agent (PA) model of insurance supply. Crop
insurance is found marginally commercially viable in riverine flood plain areas. The expected indemnity payable consistently
exceeds the expected insurance premium receivable by the insurer for the households living in wetland basin and coastal floodplain.
We conclude that a uniform structure of crop insurance market does not exist in Bangladesh. The nature of the disaster risks
faced by the farm households and the socio-economic characteristics of the rural farm communities need to be taken into careful
consideration while designing such an insurance scheme.
相似文献
Sonia AkterEmail: |
154.
155.
Religious harassment claims in the United States have risen sharply over the past decade. However, victims of religious harassment may not always report harassment, and true rates may be higher. Hence, actions taken by third parties present (observers) are important in combating harassment in the workplace. The purpose of this paper is to extend a previous model of observer intervention and related research by testing it empirically in the context of religious harassment and identify factors that influence observers' decision to intervene (intervention), when they intervene (level of immediacy), and how much they intervene (level of involvement). Across two studies, we find evidence that verbal harassment, ambiguity of intent, relationship to target/harasser, recurrence belief, religious commitment, pro‐social orientation, and the interactive effect of shared religion and religious commitment predict intervention. Furthermore, individuals show higher levels of involvement and immediacy in intervention when costs are low and emotional reactions are high. Implications of these findings for engaging observers in combatting harassment are discussed. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
156.
Jenkins TF Hewitt AD Grant CL Thiboutot S Ampleman G Walsh ME Ranney TA Ramsey CA Palazzo AJ Pennington JC 《Chemosphere》2006,63(8):1280-1290
Environmental investigations have been conducted at 23 military firing ranges in the United States and Canada. The specific training facilities most frequently evaluated were hand grenade, antitank rocket, and artillery ranges. Energetic compounds (explosives and propellants) were determined and linked to the type of munition used and the major mechanisms of deposition. 相似文献
157.
Lee T Kreidenweis SM Collett JL 《Journal of the Air & Waste Management Association (1995)》2004,54(5):585-592
The ionic compositions of particulate matter with aerodynamic diameter < or = 2.5 microm (PM2.5) and size-resolved aerosol particles were measured in Big Bend National Park, Texas, during the 1999 Big Bend Regional Aerosol and Visibility Observational study. The ionic composition of PM2.5 aerosol was dominated by sulfate (SO4(2-)) and ammonium (NH4+). Daily average SO4(2-) and NH4+ concentrations were strongly correlated (R2 = 0.94). The molar ratio of NH4+ to SO4(2-) averaged 1.54, consistent with concurrent measurements of aerosol acidity. The aerosol was observed to be comprised of a submicron fine mode consisting primarily of ammoniated SO4(2-) and a coarse particle mode containing nitrate (NO3-). The NO3- appears to be primarily associated with sea salt particles where chloride has been replaced by NO3-, although formation of calcium nitrate (Ca(NO3)2) is important, too, on several days. Size-resolved aerosol composition results reveal that a size cut in particulate matter with aerodynamic diameter < or = 1 microm would have provided a much better separation of fine and coarse aerosol modes than the standard PM2.5 size cut utilized for the study. Although considerable nitric acid exists in the gas phase at Big Bend, the aerosol is sufficiently acidic and temperatures sufficiently high that even significant future reductions in PM2.5 SO4(2-) are unlikely to be offset by formation of particulate ammonium nitrate in summer or fall. 相似文献
158.
Global warming, the major environmental issue confronted by humanity today, is caused by rising level of green house gases. Carbon capture and storage technologies offer potential for tapering CO2 emission in the atmosphere. Adsorption is believed to be a promising technology for CO2 capture. For this purpose, a polyester was synthesized by polycondensation of1,3,5-benzenetricarbonyl trichloride and cyanuric acid in pyridine and dichloromethane mixture. The polymer was then characterized using FT-IR, TGA, BET surface area and pore size analysis, FESEM and CO2 adsorption measurements. The CO2 adsorption capacities of the polyester were evaluated at a pressure of 1 bar and two different temperatures(273 and 298 K).The performance of these materials to adsorb CO2 at atmospheric pressure was measured by optimum CO2 uptake of 0.244 mmol/g at 273 K. The synthesized polyester, therefore, has the potential to be exploited as CO2 adsorbent in pre-combustion capture process. 相似文献