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991.
A novel mixed bacterial culture was enriched from an endosulfan (6, 7, 8, 9, 10, 10 - hexachloro-1, 5, 5a, 6, 9, 9a-hexahydro-6, 9-methano-2, 3, 4-benzo (e) dioxathiepin-3-oxide) processing industrial surface soil. The cultures were successful in the degradation of aqueous phase endosulfan in both aerobic and anaerobic conditions. Using the cultures, endosulfan degradation in silty gravel with sand (GM) was examined via pilot scale reactor at an endosulfan concentration of 0.78 +/- 0.01 mg g(- 1) of soil, and optimized moisture content of 40 +/- 1%. During operation, vertical spatial variability in endosulfan degradation was observed within the reactor. At the end of 56 days, maximum endosulfan degradation efficiency of 78 +/- 0.2% and 86.91 +/- 0.2% was observed in the top and bottom portion of the reactor, respectively. Both aerobic and anaerobic conditions were observed within the reactor. However, endosulfan degradation was predominant in anaerobic condition and the total protein concentration in the reactor was declined progressively down the soil depth. Throughout the study, no known intermediate metabolites of endosulfan reported by previous researchers were observed. 相似文献
992.
Sex-specific nest defense in house sparrows (Passer domesticus) varies with badge size of males 总被引:2,自引:0,他引:2
Heinz-Ulrich Reyer Wiltrud Fischer Pascale Steck Thomas Nabulon Philip Kessler 《Behavioral ecology and sociobiology》1998,42(2):93-99
According to indicator models of sexual selection, females can benefit from choosing males with above average epigamic traits,
but empirical evidence for such benefits is scarce. Here, we report results from an experiment with 29 pairs of house sparrows
(Passer domesticus) where the intensity of nest defense against a mounted mustelid predator was related to the size of the black throat and
breast patch (“badge”) in males. Using principal components analysis (PCA), original response variables of both sexes were
reduced to two factors: “Approach” to the predator and “Distant warning”. “Approach”, the more risky behavior, increased from
small- through medium- to large-badged males and decreased in their females. Since large-badged males have a higher certainty
of paternity (i.e. greater benefits from defense) and may be older and more experienced (i.e. incur lower costs), the most
likely explanation for male defense intensity increasing with badge size is an improving benefit/cost ratio. The resulting
optimal response of their females and evolutionarily stable participation in joint parental care is illustrated by a graphical
model. It shows that females would, indeed, benefit directly from choosing large-badged males. This, however, is no proof
of a direct evolutionary tie between badge size and paternal behavior, as assumed by indicator models of sexual selection.
It may simply represent a spurious relationship, originating from the correlation of badge size and defense with confidence
of paternity.
Received: 22 September 1997 / Accepted after revision: 3 November 1997 相似文献
993.
Sotiriou M Ferguson SF Davey M Wolfson JM Demokritou P Lawrence J Sax SN Koutrakis P 《Environmental monitoring and assessment》2008,137(1-3):351-361
Particles in a dental office can be generated by a number of instruments, such as air-turbine handpieces, low-speed handpieces,
ultrasonic scalers, bicarbonate polishers, polishing cups, as well as drilling and air sprays inside the oral cavity. This
study examined the generation of particles during dental drilling and measured particle size, mass, and trace elements. The
air sampling techniques included both continuous and integrated methods. The following particle continuous measurements were
taken every minute: (1) size-selective particle number concentration (Climet); (2) total particle number concentration (PTRAK),
and; (3) particle mass concentration (DustTrak). Integrated particle samples were collected for about 5 h on each of five
sampling days, using a PM2.5 sampler (ChemComb) for elemental/organic carbon analysis, and a PM10 sampler (Harvard Impactor) for mass and elemental analyses. There was strong evidence that these procedures result in particle
concentrations above background. The dental procedures produced number concentrations of relatively small particles (<0.5 μm)
that were much higher than concentrations produced for the relatively larger particles (>0.5 μm). Also, these dental procedures
caused significant elevation above background of certain trace elements (measured by X-ray fluorescence) but did not cause
any elevation of elemental carbon (measured by thermal optical reflectance). Dental drilling procedures aerosolize saliva
and products of drilling, producing particles small enough to penetrate deep into the lungs. The potential health impacts
of the exposure of dental personnel to such particles need to be evaluated. Increased ventilation and personal breathing protection
could be used to minimize harmful effects. 相似文献
994.
Wang Y Hopke PK Rattigan OV Chalupa DC Utell MJ 《Journal of the Air & Waste Management Association (1995)》2012,62(8):880-887
Black carbon (BC), an important component ofthe atmospheric aerosol, has climatic, environmental, and human health significance. In this study, BC was continuously measured using a two-wavelength aethalometer (370 nm and 880 nm) in Rochester; New York, from January 2007 to December 2010. The monitoring site is adjacent to two major urban highways (I-490 and I-590), where 14% to 21% of the total traffic was heavy-duty diesel vehicles. The annual average BC concentrations were 0.76 microg/m3, 0.67 microg/m3, 0.60 microg/m3, and 0.52 microg/m3 in 2007, 2008, 2009, and 2010, respectively. Positive matrix factorization (PMF) modeling was performed using PM2.5 elements, sulfate, nitrate, ammonia, elemental carbon (EC), and organic carbon (OC) data from the US. Environmental Protection Agency (EPA) speciation network and Delta-C (UVBC370nm-BC880nm) data. Delta-C has been previously shown to be a tracer of wood combustion factor It was used as an input variable in source apportionment models for the first time in this study and was found to play an important role in separating traffic (especially diesel) emissions from wood combustion emissions. The result showed the annual average PM2.5 concentrations apportioned to diesel emissions in 2007, 2008, 2009, and 2010 were 1.34 microg/m3, 1.25 microg/m3, 1.13 microg/m3, and 0.97 microg/m3, respectively. The BC conditional probability function (CPF) plots show a large contribution from the highway diesel traffic to elevated BC concentrations. The measurements and modeling results suggest an impact of the US Environmental Protection Agency (EPA) 2007 Heavy-Duty Highway Rule on the decrease ofBC and PM2.5 concentrations during the study period. 相似文献
995.
Philip de Pous Albert Montori Fèlix Amat Delfí Sanuy 《Regional Environmental Change》2016,16(4):995-1009
Many studies have identified climate warming to be among the most important threats to biodiversity. Climate change is expected to have stronger effects on species with low genetic diversity, ectothermic physiology, small ranges, low effective populations sizes, specific habitat requirements and limited dispersal capabilities. Despite an ever-increasing number of studies reporting climate change-induced range shifts, few of these have incorporated species’ specific dispersal constraints into their models. Moreover, the impacts of climate change on genetic variation within populations and species have rarely been assessed, while this is a promising direction for future research. Here we explore the effects of climate change on the potential distribution and genetic variation of the endemic Pyrenean newt Calotriton asper over the period 2020–2080. We use species distribution modelling in combination with high-resolution gridded climate data while subsequently applying four different dispersal scenarios. We furthermore use published data on genetic variation of both mtDNA and AFLP loci to test whether populations with high genetic diversity (nucleotide diversity and expected heterozygosity) or evolutionary history (unique haplotypes and K clusters) have an increased extinction risk from climate change. The present study indicates that climate change drastically reduces the potential distribution range of C. asper and reveals dispersal possibilities to be minimal under the most realistic dispersal scenarios. Despite the major loss in suitable climate, the models highlight relatively large stable areas throughout the species core distribution area indicating persistence of populations over time. The results, however, show a major loss of genetic diversity and evolutionary history. This highlights the importance of accounting for intraspecific genetic variation in climate change impact studies. Likewise, the integration of species’ specific dispersal constraints into projections of species distribution models is an important step to fully explore the effects of climate change on species potential distributions. 相似文献
996.
997.
Arthur L. Benson Philip L. Levins Arthur A. Massucco Donald B. Sparrow James R. Valentine 《Journal of the Air & Waste Management Association (1995)》2013,63(3):274-277
This paper is directed to those interested in measuring trace metals in high-temperature particulate emissions. Particulate handsheet filters with satisfactory purity, efficiency, thermal stability, cost, strength (about 1 lb/in.), and flexibility for analysis of particulates in gases up to 800°C have been made with 99.2% Si02 Microquartzfibers. Almost all purity requirements for optimum atomic absorption and flame emission spectrophotometric analysis for trace metals have been achieved. The filters appear highly promising for X-ray fluorescence analysis but should be further evaluated. Suitability of the filters for neutron activation analysis is uncertain and should also be further evaluated. Dioctyl phthal-ate (DOP) aerosol efficiencies of 99 to 99.99% have been achieved by using fibers of various diameters. The filters are insensitive to humidity, insoluble In most acids and organic solvents. The handsheet filters have a slightly alkaline pH, but similar filters have been made on a papermaking machine with a pH of 6.4. Cost is estimated to be about $2.00/ft2. 相似文献
998.
John W. Spence Philip L. Hanst Bruce W. Gay Jr. 《Journal of the Air & Waste Management Association (1995)》2013,63(10):994-996
Chlorinated atmospheric pollutants are presently receiving much attention because of expected chlorine-ozone interactions in the stratosphere.1,2 The fully halogenated pollutants,such as CCI3F, CCl2F2, and CCl4, have no known removal processes that operate in the troposphere. These compounds are accumulating on a global scale, their atmospheric mixing ratios having reached about 2 X 10-10 for CCl2F2,1.2 X 10-10 for CCl3F, and 9 X 10-11 for CCl4.3-5 相似文献
999.
Philip H. Taylor John F. Chadbourne 《Journal of the Air & Waste Management Association (1995)》2013,63(6):729-731
A viable chemical surrogate for monitoring the effectiveness of hazardous waste incinerators must include high thermal stability and low toxicity among its characteristics. The relationship between sulfur hexafluoride (SF6) and hazardous constituent thermal stability for a mixture of chlorinated hydrocarbons indicates that SF6 has the potential to satisfy the basic requirements of a chemical surrogate for hazardous waste incineration. 相似文献
1000.
Paris E. Georghiou Philip A. Blagden David A. Snow Linda Winsor David T. Williams 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1583-1585
Abstract Hazardous waste sites and industrial facilities contain area sources of fugitive emissions. Emission rate measurements or estimates are necessary for air pathway assessments for these sources. Emission rate data can be useful for the design of emission control and remediation strategies as well as for predictive modeling for population exposure assessments. This paper describes the use of a direct emission measurement approach – the enclosure approach using an emission isolation flux chamber – to measure emission rates of various volatile organic compounds (VOCs) from contaminated soil and water. A variety of flux chamber equipment designs and operating procedures have been employed by various researchers. This paper contains a review of the design and operational variables that affect the accuracy and precision of the method. Guidance is given as to the optimum flux chamber design and operating conditions for various types of emission sources. Also presented is a generic quality control program that gives the minimum number of duplicate, blank, background, and repeat samples that should be performed. 相似文献