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241.
OBJECTIVE: Key features of graduated licensing were introduced in 46 states and the District of Columbia between 1993 and 2003. State evaluations consistently have reported positive overall effects and positive effects of nighttime and passenger restrictions. Sixteen year-olds are the main target of graduated licensing, and the present study investigated changes in their fatal crash involvement and crash characteristics that have taken place nationally during 1993-2003. By looking at 16 year-olds nationally, the study does not constitute a direct test of the effect of graduated licensing laws per se. METHODS: Data on fatal crashes were obtained from the Fatality Analysis Reporting System. Sixteen year-olds were compared with older drivers. RESULTS: During these years, the extent to which 16-year-old drivers were in fatal crashes decreased substantially compared with older age groups. The drop in the per capita crash rate for 16 year-olds was 26%. The major change was a reduction in crashes involving transporting young passengers, especially in jurisdictions with restrictions that target these crashes. There was no change in the proportion of fatal late-night crashes even in states restricting this activity. CONCLUSIONS: There has been some progress nationally in reducing the crash problem for 16 year-olds, but this still is a big problem. To achieve further progress, the gaps and weaknesses in present graduated licensing laws will need to be addressed.  相似文献   
242.
OBJECTIVE: This study addressed the effects of vehicle height mismatch in side impact crashes. A light truck or SUV tends to strike the door of a passenger car higher causing the upper border to lead into the occupant space. Conversely, an impact centered lower on the door, from a passenger car, causes the lower border to lead. We proposed the hypothesis that the type of injury sustained by the occupant could be related to door orientation during its intrusion into the passenger compartment. METHOD: Data on door orientation and nearside occupant injuries were collected from 125 side impact crashes reported in the CIREN database. Experimental testing was performed using a pendulum carrying a frame and a vehicle door, impacting against a USDOT SID. The frame allowed the door orientation to be changed. A model was developed in MADYMO (v 6.2) using the more biofidelic dummies, BIOSID, and SIDIIs as well as USDOT SID. RESULTS: In side impact crashes with the lower border of the door leading, 81% of occupants sustained pelvic injury, 42% suffered rib fractures, and the rate of organ injury was 0.84. With the upper border leading, 46% of occupants sustained pelvic injury, 71% sustained rib fracture, and the rate of organ injuries per case increased to 1.13. The differences in the groups with respect to pelvic injury were significant at p = 0.01, rib fracture, p = 0.10, and organ injury, p = 0.001. Experimental testing showed that when the door angle changed from lower to upper border leading, peak T4 acceleration increased by 273% and pelvic acceleration decreased by 44%. The model demonstrated that when the door angle changed from lower to upper border leading, the USDOT SID showed a 29% increase in T4 acceleration and a 57% decrease in pelvic acceleration. The BIOSID dummy demonstrated a 36% increase in T1 acceleration, a 44% increase in abdominal rib 1 deflection, a 91% increase in thoracic rib 1 deflection, and a 33% decrease in pelvic acceleration. CONCLUSIONS: These data add more insight to the problem of mismatch during side impacts, where the bumper of the striking vehicle overrides the door beam, causing the upper part of the door to lead the intrusion into the passenger compartment. Even with the same delta V and intrusion, with the upper border of the door leading, more severe chest and organ injuries resulted. This data suggests that door orientation should be considered when testing subsystems for side impact protection.  相似文献   
243.
The diversity of shelters used in transitional settlements for internally displaced persons (IDPs) in Herat, Afghanistan is described. The information is based on a field survey undertaken in March 2002 and highlights the adaptation techniques, which IDPs undertake to improve any provided shelter. Potential areas for improvement are indicated; for example, the possibility for using insulated, demountable liners to prevent cold-related deaths without sacrificing shelter flexibility along with the likely need for better agency coordination of the shelter responses they provide. The wider context in which the technical recommendations would be implemented must also be considered. Such issues include agency resources, political impediments to providing the desired option, and the preference of many IDPs that the best shelter would be their home.  相似文献   
244.
Researchers attempting to integrate socio-economic data in watershed planning often draw on nationally collected census data. However, there are critical limitations to the usefulness of this type of data for decision makers operating at the watershed scale. In this paper we demonstrate the relevance of spatially referenced socio-economic data collected using mail surveys to random selections of rural landholders. The issue explored was dryland salinity management in two large watersheds in the Murray-Darling Basin of south-eastern Australia. Contrary to the assumptions underlying public policy in Australia, but consistent with the literature on farmer knowledge, comparisons of expert maps and landholder identified salinity sites suggested that landholders in these watersheds had excellent knowledge of the current extent of salinity on their property. Our research also suggested that salinity education was a sound investment by governments. At the same time, the expert maps failed to predict half of the saline affected sites identified by landholders. Accurately mapping the extent of salinity would seem a first step in addressing this nationally significant land degradation issue.  相似文献   
245.
A graduated licensing (GL) program was introduced in Nova Scotia, Canada, in October 1994. Previous research has shown that it reduced collisions in the short term. The present study examined the relative contribution of each stage of the program (i.e., learner and intermediate levels) and the program's impact after beginning drivers graduated to full licensure. The research focused on teenage beginning drivers (age 16-17), but the effects on older beginners also was examined. Per-driver crash rates of two groups of novices selected from driver records in Nova Scotia were compared. One group (pre-GL) received their learner's permits during the 2 years before the program was implemented, and the second group (GL) received their learner's permits during the 2 years after implementation. The findings clearly establish that most of the collision reduction in Nova Scotia's program occurred during the first year of the program, particularly during the first 6 months when the majority of novices were driving under supervision. The collision rate for 16 to 17-year-old GL novices was 50% lower than the rate for pre-GL novices during the 6 months after they received their learner's permits, and about 10% lower during their first 2 years of licensure when unsupervised driving from midnight to 5 A.M. was prohibited. Much of this improvement for 16 to 17-year-olds occurred during restricted night hours. Collision rates also were lower during nonrestricted hours in the initial 6 months of licensure. The 3-month "time discount" for driver education provided no safety benefit, and GL novices with driver education had collision rates that were not lower than pre-GL novices. There was no long-term effect found for the program after 16 to 17-year-olds graduated to full licensure. For older beginning drivers, crash rates during the first year after obtaining a learner's permit showed a 31% reduction. This effect diminished rapidly. There was only a 2% reduction during the first year of licensure, and crash rates increased during the following 2 years. Overall the data indicate substantial benefits of graduated licensing for 16 to 17-year-old beginners, but no benefits beyond the learner stage for older beginners.  相似文献   
246.
Determining the human health dangers from potential contamination sources, within a wellhead protection area (WHPA), requires that a risk analysis be undertaken. In this study, a desktop geographic information system and spreadsheet software are used to implement an EPA risk screening methodology for WHPAs called 'Managing Ground Water Contamination Sources in Wellhead Protection Areas--A Priority Setting Approach'. The methodology was applied to a WHPA in Gaston County, North Carolina. Results indicate that the risk of well contamination from an interstate highway and gas station with old steel underground storage tanks were comparatively high. Medium risks included a thoroughfare and highway, while low risks were assigned to machine shops, a body shop, septic systems and a gas station with new underground storage tanks and secondary containment. A sensitivity analyses of the Priority Setting Approach indicated that risk scores were extremely sensitive to hydrogeologic variables such as hydraulic conductivity. It is recommended that risk assessors utilize a range of hydrogeologic parameters to assess overall risk from each potential contamination source.  相似文献   
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249.
Life table estimates of intrinsic rate of natural increase (r) were used to assess chronic toxicity of Kepone to the copepod Eurytemora affinis (Poppe). The acute toxicity (48-h LC 50) was determined to be 40g 1-1 (95% CL 33.9–47.2). A reduction in r was observed at all concentrations above 5 g 1-1, and r was near zero at 20 g 1-1. This was due to the combination of lowered survivorship, delayed onset of reproduction and reduced fecundity. We discuss the value of the life table approach both as an experimental protocol and an ecologically realistic bioassay of chronic effects, and document that as few as 21 d are sufficient as an adequate test duration.  相似文献   
250.
/ Regional resource use planning relies on key regional stakeholder groups using and having equitable access to appropriate social, economic, and environmental information and assessment tools. Decision support systems (DSS) can improve stakeholder access to such information and analysis tools. Regional resource use planning, however, is a complex process involving multiple issues, multiple assessment criteria, multiple stakeholders, and multiple values. There is a need for an approach to DSS development that can assist in understanding and modeling complex problem situations in regional resource use so that areas where DSSs could provide effective support can be identified, and the user requirements can be well established. This paper presents an approach based on the soft systems methodology for identifying DSS opportunities for regional resource use planning, taking the Central Highlands Region of Queensland, Australia, as a case study.  相似文献   
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