全文获取类型
收费全文 | 741篇 |
免费 | 50篇 |
国内免费 | 216篇 |
专业分类
安全科学 | 79篇 |
废物处理 | 45篇 |
环保管理 | 55篇 |
综合类 | 366篇 |
基础理论 | 108篇 |
污染及防治 | 259篇 |
评价与监测 | 36篇 |
社会与环境 | 36篇 |
灾害及防治 | 23篇 |
出版年
2024年 | 1篇 |
2023年 | 21篇 |
2022年 | 49篇 |
2021年 | 41篇 |
2020年 | 37篇 |
2019年 | 28篇 |
2018年 | 35篇 |
2017年 | 41篇 |
2016年 | 45篇 |
2015年 | 58篇 |
2014年 | 41篇 |
2013年 | 62篇 |
2012年 | 71篇 |
2011年 | 69篇 |
2010年 | 51篇 |
2009年 | 53篇 |
2008年 | 47篇 |
2007年 | 47篇 |
2006年 | 27篇 |
2005年 | 19篇 |
2004年 | 21篇 |
2003年 | 16篇 |
2002年 | 25篇 |
2001年 | 23篇 |
2000年 | 5篇 |
1999年 | 9篇 |
1998年 | 12篇 |
1997年 | 11篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1007条查询结果,搜索用时 15 毫秒
971.
972.
Younggu Her Conrad D. Heatwole Moon S. Kang 《Journal of the American Water Resources Association》2015,51(4):1072-1087
The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) has been a valuable resource for hydrological analysis, providing elevation data at a consistent resolution on a near‐global scale. However, its resolution (three arc‐second or 90 m) is sometimes too low to obtain the desired level of accuracy and precision for hydrologic analysis. We evaluated the performance of several methods for interpolating SRTM three arc‐second data to a 30‐m resolution grid to better represent topography and derive terrain characteristics of the landscape. STRM data were interpolated to 30‐m DEMs on a common grid using spline, inverse distance weighting (IDW), kriging (KR), natural neighbor methods, and cubic convolution (CC) resampling. Accuracy of the methods was assessed by comparing interpolated and resampled 30‐m grids with the reference data. Slope, aspect, sinks, and stream networks were derived for the 30‐m grids and compared on a cell‐by‐cell basis to evaluate their performance in reproducing the derivatives. The comparisons identify spline and KR as the most accurate interpolation methods, of which spline is preferred because of its relative simplicity. IDW provided the greatest bias in all methods with artifacts evident in slope and aspect maps. The performance of CC projection directly to a 30‐m resolution was comparable to spline interpolation, thus is recommended as the most convenient method for interpolating SRTM to a higher resolution. 相似文献
973.
猕猴桃是我国特有的珍贵果树资源,长江三峡库区是猕猴桃的原产中心地带,物种资源丰富,生态条件优越,发展潜力较大。本文分析了三峡库区猕猴桃的资源特点,阐述了开发利用猴桃桃资源的必要性和优越性,以及有利条件,提出了发展猕猴桃生产的若干策略。 相似文献
974.
975.
976.
TianTian Xiong Camille Dumat Antoine Pierart Muhammad Shahid Yuan Kang Ning Li Georges Bertoni Christophe Laplanche 《Environmental geochemistry and health》2016,38(6):1283-1301
The quality of cultivated consumed vegetables in relation to environmental pollution is a crucial issue for urban and peri-urban areas, which host the majority of people at the global scale. In order to evaluate the fate of metals in urban soil–plant–atmosphere systems and their consequences on human exposure, a field study was conducted at two different sites near a waste incinerator (site A) and a highway (site B). Metal concentrations were measured in the soil, settled atmospheric particulate matter (PM) and vegetables. A risk assessment was performed using both total and bioaccessible metal concentrations in vegetables. Total metal concentrations in PM were (mg kg?1): (site A) 417 Cr, 354 Cu, 931 Zn, 6.3 Cd and 168 Pb; (site B) 145 Cr, 444 Cu, 3289 Zn, 2.9 Cd and 396 Pb. Several total soil Cd and Pb concentrations exceeded China’s Environmental Quality Standards. At both sites, there was significant metal enrichment from the atmosphere to the leafy vegetables (correlation between Pb concentrations in PM and leaves: r = 0.52, p < 0.05) which depended on the plant species. Total Cr, Cd and Pb concentrations in vegetables were therefore above or just under the maximum limit levels for foodstuffs according to Chinese and European Commission regulations. High metal bioaccessibility in the vegetables (60–79 %, with maximum value for Cd) was also observed. The bioaccessible hazard index was only above 1 for site B, due to moderate Pb and Cd pollution from the highway. In contrast, site A was considered as relatively safe for urban agriculture. 相似文献
977.
Youhua Tang Pius Lee Marina Tsidulko Ho-Chun Huang Jeffery T. McQueen Geoffrey J. DiMego Louisa K. Emmons Robert B. Pierce Anne M. Thompson Hsin-Mu Lin Daiwen Kang Daniel Tong Shaocai Yu Rohit Mathur Jonathan E. Pleim Tanya L. Otte George Pouliot Jeffrey O. Young Kenneth L. Schere Paula M. Davidson Ivanka Stajner 《Environmental Fluid Mechanics》2009,9(1):43-58
A sensitivity study is performed to examine the impact of lateral boundary conditions (LBCs) on the NOAA-EPA operational Air
Quality Forecast Guidance over continental USA. We examined six LBCS: the fixed profile LBC, three global LBCs, and two ozonesonde
LBCs for summer 2006. The simulated results from these six runs are compared to IONS ozonesonde and surface ozone measurements
from August 1 to 5, 2006. The choice of LBCs can affect the ozone prediction throughout the domain, and mainly influence the
predictions in upper altitude or near inflow boundaries, such as the US west coast and the northern border. Statistical results
shows that the use of global model predictions for LBCs could improve the correlation coefficients of surface ozone prediction
over the US west coast, but could also increase the ozone mean bias in most regions of the domain depending on global models.
In this study, the use of the MOZART (Model for Ozone And Related chemical Tracers) prediction for CMAQ (Community Multiscale
Air Quality) LBC shows a better surface ozone prediction than that with fixed LBC, especially over the US west coast. The
LBCs derived from ozonesonde measurements yielded better O3 correlations in the upper troposphere. 相似文献
978.
Fenton's destruction of benzene, toluene, ethylbenzene, and xylene (BTEX) was investigated in soil slurry batch reactors. The purpose of the investigation was to quantify the enhancement of oxidation rates and efficiency by varying process conditions such as iron catalyst (Fe(II) or Fe(III); 2, 5, and 10mM), hydrogen peroxide (H2O2; 30, 150, 300 mM), and metal chelating agents (l-ascorbic acid, gallic acid, or N-(2-hydroxyethyl)iminodiacetic acid). Rapid contaminant mass destruction (97% after 3h) occurred in the presence of 300 mM H2O2 and 10 mM Fe(III). An enhanced removal rate (>90% removal after 15 min and 95% removal after 3h) was also observed by combining Fe(III), N-(2-hydroxyethyl)iminodiacetic acid and 300 mM H2O2. The observed BTEX mass removal rate constants (3.6-7.8 x 10(-4)s(-1)) were compared to the estimated rate constants (4.1-10.1 x 10(-3)s(-1)). The influence of non-specific oxidants loss (by reaction with iron hydroxides and soil organic matter) was also explored. 相似文献
979.
980.
钼酸铵分光光度法测定水中总磷的不确定度评估 总被引:1,自引:0,他引:1
依据JJG1059-1999对钼酸铵分光光度法测定水中总磷的不确定度进行了评估。分析了影响测量不确定度的各个因素。对测量结果的不确定度进行了评定和表述。 相似文献