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441.
This prospective study investigates the relationship between insulin-dependent diabetes and maternal serum levels of alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG). It also examines the potential impact on screening for Down syndrome. The population-based cohort included 20 321 pregnant women in Maine who underwent routine serum screening for Down syndrome in the second trimester. The cohort included 52 women with insulin-dependent diabetes. Maternal serum AFP levels are now routinely adjusted for insulin-dependent diabetes. These adjustments, therefore, were made routinely in the diabetic women, but no equivalent adjustments were made for uE3 and hCG values. The initial false-positive rate (using all three markers) among the women with diabetes was not significantly different from that in the non-diabetic population (7·7 and 5·4 per cent, respectively). Prior to adjustment for insulin-dependent diabetes, the median AFP level in the 52 women was 0·73 multiples of the median (MOM); the median levels of uE3 and hCG were 0·93 and 0·98 MOM, respectively. When the uE3 and hCG levels were adjusted, the initial false-positive rate was unchanged. Median serum levels of uE3 were significantly higher in the 33 women whose onset of diabetes was prior to 19 years of age (0·99 MOM) than in the 19 women whose onset of diabetes was at age 19 or older (0·84 MOM). This is the first population-based study to investigate the relationship between diabetes and serum levels of AFP, uE3, and hCG, and confirms earlier observations from a case—control study that found only slightly lower uE3 and hCG levels. 相似文献
442.
In order to determine whether clinoptilolite, a naturally occurring zeolite, had any ameliorative effect on lead (Pb) toxicity to fungi, a series of growth experiments were performed. Three fungi, Aspergillus niger, Botrytis cinerea, and Fusarium culmorum, were grown on appropriately amended solid agar media, and their linear extension rates determined. B. cinerea was 25% inhibited, as compared to a control, at 100 mg dm(-3) Pb, and completely inhibited at 1000 mg dm(-3) Pb. F. culmorum was completely inhibited, and A. niger 97% inhibited at 1000 mg dm(-3) Pb. The addition of 3% clinoptilolite partially removed this inhibition in the case of A. niger and B. cinerea and almost completely removed it for F. culmorum. At a constant 500 mg dm(-3) Pb, increasing concentrations of clinoptilolite increased the linear extension rate of F. culmorum and B. cinerea, close to the rates achieved by the untreated controls. A. niger was not inhibited markedly at this Pb concentration. The evidence suggests that the Pb is adsorbed by the clinoptilolite which reduces the availability, and hence toxicity, of the metal to the fungi. 相似文献
443.
McFarland MJ Palmer GR Kordich MM Pollet DA Jensen JA Lindsay MH 《Journal of the Air & Waste Management Association (1995)》2005,55(8):1111-1121
The U.S. Department of Defense approved activities conducted at the Utah Test and Training Range (UTTR) include both operational readiness test firing of intercontinental ballistic missile motors as well as the destruction of obsolete or otherwise unusable intercontinental ballistic missile motors through open burn/open detonation (OB/ OD). Within the Utah Division of Air Quality, these activities have been identified as having the potential to generate unacceptable noise levels, as well as significant amounts of hazardous air pollutants. Hill Air Force Base, UT, has completed a series of field tests at the UTTR in which sound-monitoring surveillance of OB/OD activities was conducted to validate the Sound Intensity Prediction System (SIPS) model. Using results generated by the SIPS model to support the decision to detonate, the UTTR successfully disposed of missile motors having an aggregate net explosive weight (NEW) of 56,500 lbs without generating adverse noise levels within populated areas. These results suggest that, under appropriate conditions, missile motors of even larger NEW may be detonated without exceeding regulatory noise limits. In conjunction with collecting noise monitoring data, air quality data was collected to support the development of air emission factors for both static missile motor firings and OB/OD activities. Through the installation of 15 ground-based air samplers, the generation of combustion fixed gases, hazardous air pollutants, and chlorides were monitored during the 56,500-lb NEW detonation event. Comparison of field measurements to predictions generated from the U.S. Navy's energetic combustion pollutant formation model, POLU4WN, indicated that, as the detonation fireball expanded from ground zero, organic compounds as well as carbon monoxide continued to oxidize as the hot gases reacted with ambient air. Hazardous air pollutant analysis of air samplers confirmed the presence of chloromethane, benzene, toluene, 1,2-propadiene, and 2-methyl-l-propene, whereas the absence of hydrogen chloride gas suggested that free chlorine is not generated during the combustion process. 相似文献
444.
The activity of the enzymes aminoacyl-tRNA synthetases (AARS) in adult females and males and copepodites stage V of Calanus helgolandicus was studied at the L4 time-series station in the English Channel from June 2002 to December 2003. AARS activity was explored
as an index of somatic growth in the laboratory as well as in the field by comparison with other methods of measuring growth:
(1) the direct method (Heinle in Chesapeake Sci 7:59–74, 1966), (2) the weight increment (WI) method, (3) the Hirst and Bunker (HB) equation (Limnol Oceanogr 48(5):1988–2010, 2003) and (4) the egg production (EPR) method. AARS activity showed a significant correlation with the direct measurement of growth
in the laboratory (R
2=0.55). However, the correlation was lower for growth assessed either with the WI or the HB approaches in the field (R
2=0.05–0.17). Female AARS activity showed a positive correlation with specific EPR during the reproductive season (R
2=0.40) but no relationship was found during the non-reproductive period. 相似文献
445.
446.
447.
Glenn L. Wise 《环境质量管理》1995,4(3):21-32
Ciba-Geigy is a specialty chemical and pharmaceutical company that is managing over 100 CERCLA and RCRA remediation sites in 38 states. The potential cost is over $500 million. The sites vary in their scope and technical complexity. For years management was frustrated by their lack of control over the selection of cleanup remedies and associated costs. This article shows how the company changed the method of managing remediation projects in an attempt to gain control over the process and improve overall environmental quality performance. 相似文献
448.
Glenn E. Moglen Richard H. McCuen 《Journal of the American Water Resources Association》1990,26(1):145-156
ABSTRACT: A framework for combining economic factors and the hydrolo of detention basins is provided. The general development of economic production functions for water quality (sediment) and flood control is discussed. Example production functions are generated to compare water quality (sediment control only) and flood control. For the given example, the design of a detention basin for downstream sediment control is economically unwarranted. When compared to on-site detention facilities, regional detention structures appear to be more practical from an economic standpoint for water quality control. Since sediment was the only water quality parameter assessed, it is entirely possible that the design of a detention basin for water quality control would be justified if the effects of all pollutants of concern could be quantified. Policy aspects of detention facilities that relate to the economics of water quality control are also discussed. 相似文献
449.
Sociological edge effects: Spatial distribution of human impact in suburban forest fragments 总被引:4,自引:0,他引:4
Glenn R. Matlack 《Environmental management》1993,17(6):829-835
Suburban forest fragments often experience heavy recreational and waste disposal use, with considerable damage to the vegetation.
To suggest strategies for conservation of the forest flora, spatial distributions of human impact were described in 40 fragmentary
stands in northern New Castle County, Delaware. The distribution of human impact showed a significant bias to the forest edge,
with 95% of localized damage occurring in the first 82 m. Forms of impact related to lawn maintenance fell significantly closer
to the edge than impacts related to recreation and showed the strongest edge orientation. Edge distances of campsites, vandalized
trees, and firewood gathering were negatively correlated with distance to the nearest graded road, indicating the importance
of road access. Several forms of impact were also clustered near footpaths, although distance to paths was independent of
edge distance in all cases. In terms of penetration of the forest and severity of damage, human impact greatly exceeds natural
edge effects reported for this community. These findings suggest that damage may be minimized by limiting road access and
avoiding the creation of small forest fragments. 相似文献
450.
This article describes how Boeing'S program to conduct environmental assessments has developed since its inception five years ago, and has contributed to the company'S overall Quality Improvement process. 相似文献