全文获取类型
收费全文 | 309篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 18篇 |
环保管理 | 84篇 |
综合类 | 28篇 |
基础理论 | 65篇 |
污染及防治 | 71篇 |
评价与监测 | 7篇 |
社会与环境 | 16篇 |
灾害及防治 | 2篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 33篇 |
2012年 | 11篇 |
2011年 | 18篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 8篇 |
2007年 | 13篇 |
2006年 | 19篇 |
2005年 | 12篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 2篇 |
1979年 | 6篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1962年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有316条查询结果,搜索用时 421 毫秒
81.
Michelle Cardoso Fred Fulton Jack P. Callaghan Michel Johnson 《International journal of occupational safety and ergonomics》2019,25(3):344-354
Purpose. The main purpose of this research study was to evaluate changes in fatigue, stress and vigilance amongst commercially licensed truck drivers involved in a prolonged driving task. The secondary purpose was to determine whether a new ergonomic seat could help reduce both physical and cognitive fatigue during a prolonged driving task. Two different truck seats were evaluated: an industrial standard seat and a new truck seat prototype. Methods. Twenty male truck drivers were recruited to attend two testing sessions, on two separate days, with each session randomized for seat design. During each session, participants performed two 10-min simulated driving tasks. Between simulated sessions, participants drove a long-haul truck for 90 min. Fatigue and stress were quantified using a series of questionnaires whereas vigilance was measured using a standardized computer test. Results. Seat interactions had a significant effect on fatigue patterns. Conclusion. The new ergonomic seat design holds potential in improving road safety and vehicle accidents due to fatigue-related accidents. 相似文献
82.
Dense nonaqueous phase liquids (DNAPLs) are immiscible with water and can give rise to highly fingered fluid distributions when infiltrating through water-saturated porous media. In this paper, a conceptual mobile–immobile–zone (MIZ) model is presented to describe the structure of a DNAPL finger in water-saturated porous media and the velocity of finger propagation. A finger is composed of a finger body and a tip. The finger body has a mobile core and an immobile sheath. All the DNAPL within the tip of a finger is mobile. Lab experiments utilizing image analyses of a DNAPL (PCE) penetrating into water-saturated homogeneous glass beads were carried out in a two-dimensional transparent chamber. The results show that the fingers elongated almost linearly with time. The fingers did not grow laterally after the tip of the finger had passed. The average finger diameters were between 3.9 and 5.4 mm for PCE propagation in water-saturated glass bead porous media with mean particle diameters from 0.32 to 1.36 mm. The estimated mobile core diameters were 51–60% of the average finger diameters. 相似文献
83.
The changes in the vascular plant flora of Tasiilaq, low arctic Southeast Greenland, between around 1900 and 2007 were studied
by comparing the data from historical literature with those of the field observations performed between the late 1960s and
2007. Since 1900, the percentage of widely distributed arctic species distinctly decreased, whereas that of the low arctic
species somewhat increased, and boreal species hardly increased. Vegetation monitoring revealed minor changes and showed that
several thermophilous and xerophilous species increased between 1968/1969 and 2007, whereas some hygrophilous species decreased.
Repeated vegetation mapping of a shallow pond revealed conspicuous changes suggesting increased evaporation/precipitation
ratios associated with environmental warming up and decreasing snow accumulation in winter, in line with results of previous
investigations. In spite of climate warming, expansion of the town and increasing human impact, flora and vegetation on the
whole appeared rather stable during the last 40 years without invading species or introductions. 相似文献
84.
Fred M. Vukovich John Sherwell 《Journal of the Air & Waste Management Association (1995)》2013,63(5):573-584
Abstract This study compared the variations in the mass of certain particles at an urban site, Washington, DC, and at a remote site, Shenandoah National Park, VA, in the eastern United States. Seven years (1991-1997) of Interagency Monitoring of Protected Visual Environments (IMPROVE) fine particulate matter (PM2.5), PM10, coarse fraction, SO4 2?, and total sulfur data were used for this study together with available meteorology/climatology data. Various statistical modeling and analysis procedures, including time series analysis, factor analysis, and regression modeling, were employed. Time series of the constituents were divided into four terms: the long-term mean, the intra-annual perturbation, the interannual perturbation, and the synoptic perturbation. PM2.5 at the two sites made up ~72% of the total mass for PM10, and the coarse fraction made up the remaining 28%, on average. Thirty-one percent of the PM2.5 at the DC site and 42% at the Shenandoah site was SO4 2?, based on average data for the entire period. At the DC site, the two main contributors to the constituent mass were the long-term mean and the synoptic perturbation terms, and at the Shenandoah site, they were the long-term mean and the intra-annual perturbation terms. This suggested that the constituent mass at the two sites was affected by very different processes. The terms that provided the principal contribution to the constituent mass at the two sites were studied in detail. At the DC site, dew point trends, a climate variable, were the primary driver of the 7-year trends for PM2.5, PM10, the coarse fraction, and total sulfur, and SO2 emission trends were the primary driver of the trends for SO4 2?. SO2 emission trends influenced the trends for PM2.5 and total sulfur, appearing as the second term in the model, but only parameters dealing with climate trends had significant effects on the trends for PM10 and the coarse fraction. At the Shenandoah site, only parameters dealing with climate trends affected long-term particle trends. 相似文献
85.
86.
Norman J. Beloin Fred H. Haynie 《Journal of the Air & Waste Management Association (1995)》2013,63(4):399-403
Six building materials were exposed at five sites in Birmingham, Alabama, to determine the rates of soiling by different levels of suspended particulate. The exposed materials were (1) painted cedar siding, (2) concrete block, (3) brick, (4) limestone, (5) asphalt shingles, and (6) window glass. Suspended particulate levels ranged from an annual geometric mean of 60 μg/m3 at the clean site to 250 μg/m3 at the most polluted site. Degrees of soiling were determined by measuring reflectance from the opaque surfaces and haze through the glass. Excellent dose-response relationships were obtained for the white surfaces— painted cedar siding and asphalt shingles. The degree of soiling of the paints was directly proportional to the square root of the suspended particulate dose. The shingle soiling was directly proportional to the dose. These regression equations can account for from 74 to 92% of the variability in reflectance measurements. Similar regressions for brick can account for from 34 to 50 % of the variability. Poor correlations were obtained for concrete, limestone, and window glass. 相似文献
87.
Jun Wu Douglas Houston Fred Lurmann Paul Ong Arthur Winer 《Atmospheric environment (Oxford, England : 1994)》2009,43(12):1962-1971
The Ports of Los Angeles and Long Beach are the entry point for almost half of all cargo containers entering the United States. The use of diesel trucks to move Port-related goods has raised significant public health concerns associated with black carbon and other air pollutants. It is difficult to reliably estimate people's exposure to vehicle-related pollutants due to the narrow impact zone of traffic, usually within 200–300 m downwind of major roadways. Previous studies suffer from the lack of traffic count data on surface streets and the lack of neighborhood-level population data. We examined seasonal and annual average exposures of particulate matter less than 2.5 μm (PM2.5) and elemental carbon (EC) at a neighborhood scale for communities heavily impacted by diesel trucks near these ports. We assembled a traffic-activity database that distinguishes gasoline and diesel vehicles on both freeways and surface streets, by consolidating information from several sources, including our own field measurements. The CALINE4 model was used to estimate residential exposure of the study population to PM2.5 and EC. Parcel property data were used to allocate Census block group (BG) population to increase spatial resolution. The annual average PM2.5 and EC exposure due to local traffic was 3.8 and 0.4 μg m?3, respectively. On average, surface streets contributed a little more than freeways (55% vs. 45% for EC and 57% and 43% for PM2.5). Light-duty vehicles contributed significantly more than heavy-duty trucks for PM2.5 (61% vs. 39%), but slightly less than heavy-duty trucks for EC (49% vs. 51%). Community mean population exposure was similar using parcel, census block, and BG population data, but extreme values and standard deviations varied significantly at different spatial resolutions. The intake fraction for the study population was in the range of 1.0–2.2 × 10?5 by vehicle type, roadway type, and season. 相似文献
88.
89.
Improving the Evaluation of Conservation Programs 总被引:5,自引:0,他引:5
Devra G. Kleiman Richard P. Reading † Brian J. Miller † Tim W. Clark ‡ J. Michael Scott § John Robinson Richard L. Wallace ‡§ Robert J. Cabin †† and Fred Felleman‡‡ 《Conservation biology》2000,14(2):356-365
Abstract: The evaluation of conservation programs is rare but increasingly important in improving their effectiveness. Regular evaluations of conservation programs and the implementation of recommendations resulting from such assessments are infrequent because of resistance by participants and lack of funding. Evaluations may be internal or external, depending on the purpose of the review and how broadly it is focused. We strongly recommend external peer review of long-term complex conservation programs every 5 years, supported by more frequent (annual) internal reviews. Criteria for success must encompass both biological and social measures and include learning and the application of new knowledge to management. Evaluations must also go beyond monitoring to assess the value of the program. We emphasize the need to include the organization and function of a conservation program (the process) in any evaluation in addition to substantive criteria for success, which usually involve biological measures (numbers). A dysfunctional program organization and process can as effectively cripple a conservation effort as can a major biological catastrophe. We provide examples of different types of conservation program evaluations, including moderated workshops and case-study analysis, and provide advice on the logistics and organization of the review, emphasizing the importance of the evaluation process itself to a successful outcome. One important aspect of an evaluation is having an individual with leadership ability and considerable expertise to organize the format and oversee the review process itself. Second, it is essential at the outset to ensure agreement among the program participants and the review committee on the goals and objectives of the conservation program, what is to be evaluated, and the criteria for defining success. Finally, the best evaluations are inclusive and involve all participants and stakeholders. 相似文献
90.
大鼠类Alu重复序列的克隆及其在染色体DNA突变分析中的应用 总被引:1,自引:0,他引:1
从大鼠低Cot值DNA文库分离到一种类Alu的重复序列,命名为RALRS-1。对RALRS-1克隆并进行了测序,长度为283bp,发现其中含有单一的微卫星(microsatellite)序列AG,AGG和AGGG。RALRS-1DNA序列在大鼠单倍体基因组中的拷贝数为150000~330000。依RALRS-1中的一段序列合成了一28寡核苷酸探针(AGGG)7,对大鼠正常组织和肿瘤组织DNA指数谱 相似文献