全文获取类型
收费全文 | 475篇 |
免费 | 12篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 39篇 |
废物处理 | 30篇 |
环保管理 | 74篇 |
综合类 | 84篇 |
基础理论 | 93篇 |
污染及防治 | 111篇 |
评价与监测 | 28篇 |
社会与环境 | 27篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 9篇 |
2014年 | 20篇 |
2013年 | 51篇 |
2012年 | 15篇 |
2011年 | 35篇 |
2010年 | 19篇 |
2009年 | 21篇 |
2008年 | 25篇 |
2007年 | 30篇 |
2006年 | 28篇 |
2005年 | 21篇 |
2004年 | 20篇 |
2003年 | 23篇 |
2002年 | 16篇 |
2001年 | 5篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 7篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1961年 | 2篇 |
1957年 | 1篇 |
1956年 | 2篇 |
1955年 | 3篇 |
1949年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有494条查询结果,搜索用时 558 毫秒
191.
Alfred L. Allen Jean Mayer Robert Stote David L. Kaplan 《Journal of Polymers and the Environment》1994,2(4):237-244
Eleven microorganisms were isolated from several temperate marine locations in the northeast Altantic coast of the United States and one tropical location in the Pacific Ocean (Hawaii) for the purpose of developing a rapid and accurate method of screening biodegradable materials for their susceptibility to mineralization. The materials evaluated in this study included chemically modified starch, amylose and pullulan, poly(3-hydroxybutyrate-co-valerate), (PHB/V), cellulose acetate, and a modified lignin/styrene. Some of the soluble, unmodified, biologically produced substrates such as starch, pullulan, and amylose mineralized rapidly. In general, the synthetic, insoluble polymers and the chemically modified polymers, such as acetylated and chlorinated amylose and pullulan, mineralized more slowly, although the ultimate mineralization of some of the substituted polysaccharides equaled or exceeded that of the unmodified substrate. The insoluble bacterial polyester, PHB/V, degraded rapidly after a short induction period. Initial respiration rate data, in general, could not be used as a predictor of ultimate mineralization. It was found that the cumulative level of carbon dioxide evolved signifies the minimum extent of biodegradation of the substrate, and the oxygen consumed is a good indicator of the maximum extent of substrate degradation.Paper presented at the Biodegradable Materials and Packaging Conference, September 22–23, 1993, Natick, Massachusetts. 相似文献
192.
Jean-Luc Volumenie Pascal de Lagausie Jean Guibourdenche Jean-François Oury Edith Vuillard Carole Saizou Dominique Luton 《黑龙江环境通报》2001,21(13):1171-1174
This study aimed to analyse the influence of amnio-infusion on superior mesenteric Doppler velocimetry and to correlate Doppler data with outcome in fetuses presenting with gastroschisis. Umbilical and intra- and extra-abdominal superior mesenteric artery Doppler velocimetry was measured prospectively before and after amnio-infusion in fetuses with gastroschisis. Doppler index values and changes were correlated with the following outcome parameters: importance of fibrous coating, duration of hospitalization in the neonatal intensive care unit, total duration of hospitalization, duration of parenteral feeding, duration of ventilatory assistance, and the interval to initiation of oral feeding. A significant improvement of diastolic flow was observed in the extra-abdominal superior mesenteric artery with amnio-infusion. No similar change was seen in the intra-abdominal superior mesenteric or in the umbilical artery. Pre-amnioinfusion extra-abdominal mesenteric Doppler index was correlated with maximal diameter of exteriorized bowel and slightly with duration of hospitalization in the neonatal intensive care unit, but no other relation between Doppler index and outcome parameter could be ascertained. Amnio-infusion induces modifications in the vascularization of exteriorized bowel in gastroschisis. This could partly explain the beneficial effect of this procedure on fetal gut. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
193.
Stocki TJ Armand P Heinrich P Ungar RK D'Amours R Korpach EP Bellivier A Taffary T Malo A Bean M Hoffman I Jean M 《Journal of environmental radioactivity》2008,99(11):1775-1788
Since 2001 a real-time radiation monitoring network of Canadian nuclear facilities and major population centres has been implemented for response to nuclear incidents including a possible terrorist attack. Unshielded NaI(Tl) spectroscopic detectors are employed to measure gamma radiation from airborne radioactivity and radioactivity deposited on the ground. These detectors are composed of a standard 3'x3' cylindrical NaI(Tl) spectrometers with data storage and integrated telemetry. Some of the detectors have been deployed in the Ottawa Valley near Chalk River Laboratories and Ottawa, which has a complex radioxenon environment due to the proximity of nuclear power reactors, and medical isotope facilities. Although not a health threat, these releases have provided an opportunity for the Canadian Meteorological Centre and the Commissariat à l'Energie Atomique to validate their meteorological models. The meteorological models of the two organizations are in good agreement on the origin and the source terms of these releases. 相似文献
194.
INTRODUCTION: The purpose of the study reported here was to develop and pilot test a comprehensive battery of assessment instruments for older drivers that would be inexpensive and easy to administer so that it could be used in longitudinal studies. METHOD: The resulting battery was developed by selecting a set of validated assessment instruments and combining them into a package, with a total acquisition cost of less than $900. As part of this battery, three questionnaires were developed utilizing items from established questionnaires with minor modifications. The battery was pilot tested with a convenience sample of 38 drivers aged 65 years or older. RESULTS: Results showed that the entire battery required less than one hour to complete. Data from the assessment outcomes fell within normative ranges. Feedback from subjects indicated that the battery was acceptable, free of problems, presented tasks in a good order, and was not too long. CONCLUSIONS: Based on study findings, the assessment battery appeared to be low-cost, transportable, easy to administer, easy for subjects to complete, provides a comprehensive assessment of a person's physical health, mental health, and driving behaviors, and would serve as a valuable data collection tool for a longitudinal study of older drivers. Such a longitudinal study is needed in order to answer some of the most important questions about older driver safety and mobility. 相似文献
195.
Shope JT 《Journal of Safety Research》2007,38(2):165-175
Unintentional injury from motor-vehicle crashes is the number one cause of death among teenagers in the United States. Increasingly, jurisdictions have adopted three-stage graduated driver licensing (GDL) systems for young novice drivers. Since a previous review of U.S. GDL evaluation results, many more U.S. states and Canadian provinces have implemented GDL and/or had enough time pass that additional evaluation results are now available. Twenty-one studies of GDL within 14 individual jurisdictions, and six studies of GDL in the U.S. nationwide, were collected, reviewed, and summarized. Positive results (usually crash reductions) of varying degrees were reported from nearly all the studies. Given differences in approaches, study goals, methods, and analyses, the results are surprisingly consistent. Overall, GDL programs have reduced the youngest drivers' crash risk by roughly 20 to 40%. Research on teen driving and comprehensive GDL enhancements could further reduce teen drivers' motor-vehicle crashes, injuries, and fatalities. IMPACT ON INDUSTRY: Policy-makers, as well as the motor vehicle, insurance, and other industries have been involved in teen driving safety and could enhance and coordinate their roles. 相似文献
196.
Studies of the influence of parasites on host fitness generally conclude that parasites have a strong negative effect on their
hosts. In this study, we have investigated experimentally the role of Polymorphus minutus, an acanthocephalan parasite, on the salinity tolerance of the freshwater amphipod Gammarus roeseli, one of its intermediate hosts. Unexpectedly, P. minutus-infected gammarids were more tolerant to salinity stress than uninfected ones. The mean lethal salt concentrations for 50%
mortality of hosts tested were 17.3 (infected) and 9.7 g/L (uninfected). The parasitic load (one or two parasites per host)
did not affect the result. The size of hosts had no significant influence on the salinity tolerance of either infected or
uninfected gammarids. The mobility of all types of gammarid decreased when the salinity exceeded 9.0 g/L, but there was no
significant difference between infected and uninfected gammarids. We discuss the higher salinity tolerance of infected amphipods
in relation to O2 consumption and osmoregulation. Finally, we demonstrate that the salinity tolerance is enhanced in the parasitized amphipod
but without a significant change in behavior or an osmoregulatory adjustment. 相似文献
197.
Reservoir Sedimentation Rates in the Little Washita River Experimental Watershed,Oklahoma: Measurement and Controlling Factors
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Daniel N. Moriasi Jean L. Steiner Sara E. Duke Patrick J. Starks Alan J. Verser 《Journal of the American Water Resources Association》2018,54(5):1011-1023
Forty‐five flood control reservoirs, authorized in the Watershed Protection and Flood Prevention Act 1954, were installed by United States Department of Agriculture (USDA) between 1969 and 1982 in the Little Washita River Experimental Watershed (LWREW), located in central Oklahoma. Over time, these reservoirs have lost sediment and flood storage capacity due to sedimentation, with rates dependent on upstream land use and climate variability. In this study, sedimentation rates for 12 reservoirs representing three major land use categories within LWREW were measured based on bathymetric surveys that used acoustic profiling system. Physiographic and climate attributes of drainage area of surveyed reservoirs were extracted from publicly available data sources including topographic maps, digital elevation models, USDA Natural Resource Conservation Service soils, and weather station databases. Correlation, principal component analysis, and stepwise regression were utilized to analyze the relationship between normalized reservoir sedimentation rates (ReSRa) and the drainage area characteristics to determine the major variables controlling sedimentation within the LWREW. Percent of drainage area with extreme slopes, saturated hydraulic conductivity, and maximum daily rainfall event recorded in spring explained most of the variability in ReSRa. It was also found that percent reduction in reservoir surface area can be used as a surrogate for estimating ReSRa. The implications of the results are discussed. 相似文献
198.
In order to comply with dioxin and furan (PCDD/F) emission regulations in Belgium, the IVRO municipal waste incinerator adopted catalytic filters for use in the plant's two existing fabric filters. This system replaced the injection of powdered activated carbon (PAC) because of concerns that PAC, used at temperatures above 200 degrees C, would ignite and lead to fires and plant down-time. The performance of the catalytic filter system, since its installation in 1997, is described. PCDD/F emissions are controlled to well below the regulatory limit of 0.1 ng I-TEQ/Nm3. The amount of PCDD/F entering and exiting the fabric filter is quantified. The resulting mass balance shows that greater than 99.5% of the gaseous PCDD/F entering the fabric filter is destroyed by the catalyst within the filter media. 相似文献
199.
Introduction
Police records are the most common source of data used to estimate motor-vehicle collision risks, understand causal or contributing factors, and evaluate the efficacy of interventions. The literature notes concerns about this information citing discrepancies between police reports and other sources of injury occurrence and severity data. The primary objective of the analysis was to assess the adequacy of police reports for an examination of weather-related injury collision risk.Method
Analyses of relative risk were carried out using both police records and comprehensive insurance claim data for Winnipeg, Canada over the period 1999-2001.Results and conclusions
Both data sets yielded very similar results—precipitation substantially increases the risk of injury collision (police records: RR 1.76, CI 1.55-2.00; insurance: RR 1.80, CI 1.62-1.99) and risk of injury (police records, RR 1.74, CI 1.55-1.96; insurance, RR 1.69, CI 1.55-1.85) relative to corresponding dry weather control periods. Both rainfall and snowfall were associated with large increases in collisions and injuries.Impact on Industry
While relative risks are almost identical, over 64% more injury collisions and 74% more injuries were identified using the insurance data, which is an important difference for evaluating absolute risk and exposure. 相似文献200.
Jean Rouchaud Marc Metsue Fabrice Gustin Frans van de Steene Christian Pelerents Frans Benoit 《毒物与环境化学》2013,95(1-4):215-226
For the protection of early and summer cauliflower and brussels sprouts crops against root fly, the insecticide chlorpyrifos was applied at planting onto soil around the stem of the plant, or in the planting line. In the soil, chlorpyrifos (1) was transformed into the insecticide metabolites oxon, 0,0‐diethyl‐0‐(3,5,6‐tri‐chloro‐2‐pyridinyl) phosphate (2), and 3,5,6‐trichloro‐2‐pyridinol (3). The soil half life time of chlorpyrifos could be 2.8 times greater (42 days relative to 15 days) when the field history as to cauliflower monoculture and insecticide treatments was short (1 year), than when it was long (8 years). Rains and season also had cumulative effects on the chlorpyrifos soil half life times. In the leaves of cabbage, chlorpyrifos and compound 3 were observed at concentrations which were higher, especially when their soil concentrations were high. Chlorpyrifos and compounds 2 and 3 however were not detected in the “flower” of cauliflower, nor in the brussels sprouts itself, the limit of sensitivity being 0.02 ppm of fresh weight. 相似文献