全文获取类型
收费全文 | 214篇 |
免费 | 3篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 8篇 |
环保管理 | 60篇 |
综合类 | 17篇 |
基础理论 | 38篇 |
污染及防治 | 45篇 |
评价与监测 | 24篇 |
社会与环境 | 12篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 3篇 |
2013年 | 35篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2003年 | 9篇 |
2002年 | 2篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有222条查询结果,搜索用时 15 毫秒
91.
92.
Safety belt effectiveness in preventing fatalities to drivers is examined versus a number factors (vehicle, accident, and environmental) by applying the double-pair comparison method to appropriate subsets of the Fatal Accident Reporting System (FARS) data. For each of 13 factors studied, safety belt effectiveness (the percent of fatally injured unbelted drivers who would not have been killed if they had been wearing safety belts) is estimated, as is an associated standard error of the estimate. The results, which are presented graphically, provide no evidence that safety belt effectiveness is systematically influenced by most of the factors investigated, including car mass and model year. The absence of any systematic relationship with car mass is in agreement with an earlier finding based on the pedestrian fatality exposure method; this agreement adds plausibility to the assumptions used for both the earlier and the present methods. Safety belt effectiveness is greater for single-car crashes (62 ± 5) % than for crashes involving two cars (30 ± 8) % , this difference being statistically significant at p<.02. The results suggest weakly that safety belt effectiveness is greater for two-door (48 ± 6) % than for four-door (38 ± 10) % cars, and is greater for striking (44 ± 6) % cars than for struck (27 ± 12)% cars. The above differences probably reflect higher effectiveness in frontal (or rollover) crashes than in side impacts. 相似文献
93.
Leonard J. Greenfield Curtis R. Hare 《Journal of the American Water Resources Association》1973,9(5):923-931
ABSTRACT: Analyses of soil and water were made in a stretch of shallow ground north of a cypress head in South Florida. The area is covered with water for part of the year, and it flows slowly southward. The soil is primarily peat formed from the local graminid vegetation during its decay. The top layer consists of a blue-green algal mat whose decay products contribute to the peat also. Collections of soil (including the top layer) were made layer by layer and anlyzed for cations and anions and for ion exchange capacity. The latter appears to be high enough in all layers to account for the ion content within the soil and surrounding waters. It probably is a very important buffer system that retards limestone erosion. CEC values ranged from 20 to 190 meg/100 gm dry soil from bedrock to surface. 相似文献
94.
Summary The influence of resident females on the settling patterns of subsequent females was examined for marsh wrens (Cistothorus palustris). Proportionally more females responded to a playback of a female intruder during the pre-laying stage than during the laying
and incubation stages. The strength of the response was also greatest during pre-laying and laying stages (Table 1). Female
wrens did not settle randomly with respect to the presence of other females, but rather settled with bachelor males more often
than predicted by chance (Table 3). Female settlement within territories was more asynchronous than settlement between territories.
An attempt to fit these data to two models of female settlement suggested that prospecting females were not displaced by residents,
but rather avoided settling with mated males (Table 3). Females within territories were also more dispersed than predicted
by chance, a pattern that may be enforced through aggression on the part of the resident female. Staggered settlement reduces
the overlap in nestling stages of harem mates and so may be a strategy to reduce competition for resources at this critical
stage. 相似文献
95.
Native plant species suitable as bioindicators and biomonitors for airborne fluoride 总被引:4,自引:0,他引:4
For 30-40 years airborne fluoride, usually in the form of HF or SiF4, was one of the most important and damaging air pollutants affecting forests, crops and natural vegetation. It is much more toxic than most other air pollutants such as O3 or SO2 because injury to the most sensitive species begins when they are exposed to a concentration below 1 ppb (ca. 0.8 microg m(-3)) for a 1- to 3-day period. The long-term threshold concentration is around 0.25-0.30 microg m(-3). Higher concentrations and longer durations of exposure induce much more rapid and extensive injury. However, there is a difference in sensitivity between the most and least sensitive species of around 2-3 orders of magnitude and most species possess a degree of resistance. Dramatic improvements in engineering technology have greatly reduced emissions but because of the high toxicity, cases of vegetation injury are still common, even in developed countries, and cases involving litigation still occur. Therefore there is a continuing need for bioindicators and biomonitoring of fluorides, so this paper reviews the subject, drawing attention to the strengths and limitations of the techniques. Visible symptoms are described and illustrated and tables of relative sensitivity are given and their limitations discussed. Finally, examples of biomonitoring in Europe and the USA are presented. 相似文献
96.
97.
98.
Provisioning rules in tree swallows 总被引:7,自引:0,他引:7
Conflict between parents and offspring may result in offspring exaggerating their needs and parents devaluing their begging
signals. To determine whether this occurs, it is first necessary to establish the link between need, begging and parental
response. The purpose of our study was to examine these relationships in tree swallows (Tachycineta bicolor). Parents preferentially fed nestlings that begged sooner, reached higher and were closer to the front of the nestbox (Fig.
1). Begging intensity of both individuals and entire broods increased with relatively long periods between feeding visits.
Within broods, parents responded to increased begging intensity by increasing their feeding rate, although this effect was
relatively weak. Large and small nestlings did not differ in their begging behavior and all nestlings, regardless of size,
were fed at similar rates. Despite the overall equity in feeding, male parents preferentially fed larger nestlings while female
parents fed smaller nestlings. Nestlings did not increase their begging intensity in response to begging by nestmates. Our
results suggest that begging is related to need in this species and that parents respond to variation in begging intensity.
Received: 4 May 1995/Accepted after revision: 17 December 1995 相似文献
99.
Water solubilities (SW) determined by the HPLC generator column method are reported for a series of chlorinated dibenzo--dioxins (PCDDs) with SW ranging from 0.4 ng/L (ppt) for octa-chlorodibenzo--dioxin to 430 ng/L for 1,2,3,7-tetrachlorodibenzo--dioxin at 20°C. A correlation is demonstrated between SW and HPLC capacity factors (k′) for these extremely hydrophobic compounds, allowing calculation of SW of PCDDs from k′ and melting point data. 相似文献
100.
Burger J Myers O Boring CS Dixon C Jeitner JC Leonard J Lord C McMahon M Ramos R Shukla S Gochfeld M 《Environmental monitoring and assessment》2003,89(3):285-303
There are important linkages between the health of humans and theenvironment, restoration of degraded lands, and long-term stewardship of public lands, yet most environmental indicators deal only with assessing the physical and biological aspects ofecosystems. In this article, we examine the ratings of perceptionsof several environmental problems for their utility as indicatorsof environmental quality, and examine perceptions of future land use by people interviewed in Santa Fe, New Mexico, near the Department of Energy's (DOE) Los Alamos National Laboratory (LANL). Overall, people with lower incomes rated environmental problems as more severe than others, were more willing to spend federal funds to solve them, and were consistent in their ratingsof severity of environmental problems and their willingness to spend federal funds. Cleaning up LANL and other Department of Energy sites, received the highest rating for expenditure of federal funds. The highest rated future uses for DOE sites were for recreation and for National Environmental Research Parks. People with less education generally gave higher ratings to mostfuture land uses for DOE than did those with more education. However, those with higher education gave higher ratings to nuclear reprocessing, and nuclear material storage. Where there were differences, the people interviewed at Santa Fe rated all environmental problems (except pesticides) as more severe than did those previously interviewed in Albuquerque (located fartherfrom the LANL site), and they were more willing to spend federalfunds on these problems. Ratings for all future land uses did notdiffer between the Santa Fe and Albuquerque respondents. These perception-based indicators show general agreement among peopleliving close and farther away from LANL with respect to cleaningup LANL and the future land uses for the site. These indicators should be considered by regulators, site personnel, and policy makers in future management and land use decisions. 相似文献