全文获取类型
收费全文 | 3958篇 |
免费 | 107篇 |
国内免费 | 41篇 |
专业分类
安全科学 | 177篇 |
废物处理 | 177篇 |
环保管理 | 936篇 |
综合类 | 533篇 |
基础理论 | 853篇 |
环境理论 | 2篇 |
污染及防治 | 913篇 |
评价与监测 | 301篇 |
社会与环境 | 159篇 |
灾害及防治 | 55篇 |
出版年
2023年 | 24篇 |
2022年 | 36篇 |
2021年 | 57篇 |
2020年 | 37篇 |
2019年 | 49篇 |
2018年 | 88篇 |
2017年 | 95篇 |
2016年 | 104篇 |
2015年 | 83篇 |
2014年 | 111篇 |
2013年 | 379篇 |
2012年 | 150篇 |
2011年 | 217篇 |
2010年 | 164篇 |
2009年 | 183篇 |
2008年 | 228篇 |
2007年 | 212篇 |
2006年 | 176篇 |
2005年 | 148篇 |
2004年 | 137篇 |
2003年 | 166篇 |
2002年 | 137篇 |
2001年 | 109篇 |
2000年 | 75篇 |
1999年 | 49篇 |
1998年 | 59篇 |
1997年 | 39篇 |
1996年 | 43篇 |
1995年 | 58篇 |
1994年 | 40篇 |
1993年 | 57篇 |
1992年 | 52篇 |
1991年 | 18篇 |
1990年 | 27篇 |
1989年 | 23篇 |
1988年 | 29篇 |
1987年 | 17篇 |
1986年 | 24篇 |
1985年 | 35篇 |
1984年 | 27篇 |
1983年 | 32篇 |
1982年 | 42篇 |
1981年 | 38篇 |
1980年 | 34篇 |
1979年 | 23篇 |
1978年 | 24篇 |
1977年 | 12篇 |
1976年 | 10篇 |
1974年 | 8篇 |
1972年 | 10篇 |
排序方式: 共有4106条查询结果,搜索用时 15 毫秒
161.
Mean values of eight contaminants in Herring Gull (Larus argentatus) eggs were calculated for 15 Great Lakes sites for the 5 year period 1998–2002. The sites were ranked according to the concentrations of each of seven compounds relative to fish flesh criteria for the protection of piscivorous wildlife, and a single overall rank of contamination was calculated for each site. Based on this weighted ranking scheme, we found that sum PCBs, dioxin and DDE contributed the most (60.2, 30.5% and 8.5%, respectively) to the overall rankings. The weighted ranking scheme showed that eggs from Channel-Shelter Island (Saginaw Bay, Lake Huron), Strachan Island (St. Lawrence River) and Gull Island (northern Lake Michigan) ranked as the three most contaminated sites, while Agawa Rocks (eastern Lake Superior), Chantry Island (southern Lake Huron) and Port Colborne (eastern Lake Erie) ranked as the three least contaminated sites. Two of the three most contaminated sites are Areas of Concern; none of the three least contaminated sites are Areas of Concern. 相似文献
162.
163.
Ana L. De Toffoli Bruno H. Fumes 《Journal of environmental science and health. Part. B》2018,53(7):434-440
On-line in-tube solid phase microextraction (in-tube SPME) coupled to high performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) was successfully applied to the determination of selected triazines in water samples. The method based on the employment of a packed column containing graphene oxide (GO) supported on aminopropyl silica (Si) showed that the extraction phase has a high potential for triazines extraction aiming to its physical-chemical properties including ultrahigh specific surface area, good mechanical and thermal stability and high fracture strength. Injection volume and loading time were both investigated and optimized. The method validation using Si-GO to extract and concentrate the analytes showed satisfactory results, good sensitivity, good linearity (0.2–4.0 µg L?1) and low detection limits (1.1–2.9 ng L?1). The high extraction efficiency was determined with enrichment factors ranging from 1.2–2.9 for the lowest level, 1.3–4.9 intermediate level and 1.2–3.0 highest level (n = 3). Although the analytes were not detected in the real samples evaluated, the method has demonstrated to be efficient through its application in the analysis of spiked triazines in ground and mineral water samples. 相似文献
164.
Jian Liu Peter J. A. Kleinman Helena Aronsson Don Flaten Richard W. McDowell Marianne Bechmann Douglas B. Beegle Timothy P. Robinson Ray B. Bryant Hongbin Liu Andrew N. Sharpley Tamie L. Veith 《Ambio》2018,47(6):657-670
Winter manure application elevates nutrient losses and impairment of water quality as compared to manure applications in other seasons. In conjunction with reviewing global distribution of animal densities, we reviewed worldwide mandatory regulations and voluntary guidelines on efforts to reduce off-site nutrient losses associated with winter manure applications. Most of the developed countries implement regulations or guidelines to restrict winter manure application, which range from a regulative ban to guidelines based upon weather and field management conditions. In contrast, developing countries lack such official directives, despite an increasing animal production industry and concern over water quality. An analysis of five case studies reveals that directives are derived from a common rationale to reduce off-site manure nutrient losses, but they are also affected by local socio-economic and biophysical considerations. Successful programs combine site-specific management strategies along with expansion of manure storage to offer farmers greater flexibility in winter manure management. 相似文献
165.
166.
Sanjeev Debipersadh Timothy Sibanda Ramganesh Selvarajan Richard Naidoo 《Environmental monitoring and assessment》2018,190(8):476
Contamination of the ocean by heavy metals may have ecosystem-wide implications because they are toxic even if present in trace levels, and the relative ease of their bioaccumulation by marine organisms may affect human health, primarily through consumption of contaminated fish. We evaluated metal concentrations in six different popular edible fish species and estimated the potential health risks from consumption of contaminated fish. There was no correlation between fish length and average metal accumulation although the fish species tended to accumulate significantly more Al and Zn (P?<?0.05) than any of the other metals. Significantly higher Mn concentrations were found in fish gills compared to other body parts in all fish species. Bronze seabream, Catface rockcod, and Slinger seabream had significantly higher mean Cr concentration in the liver than in either the tissues or gills. The highest concentration of Zn in fleshy tissue was in Horse mackerel (56.71 μg g?1) followed by Bronze seabream (31.07 μg g?1). Al levels ranged from 5.6 μg g?1 in Atlantic mackerel to 35.04 μg g?1 in Horse mackerel tissue while Cu and Cr concentrations were highest in the tissues of Horse mackerel (6.83 and 1.81 μg g?1, respectively) followed by Santer seabream (3.15; 1.09 μg g?1) and Bronze seabream (3.09; 1.30 μg g?1), respectively. The highest tissue concentration of Mn was detected in Bronze seabream (8.23 μg g?1) followed by Catface rockcod (6.05 μg g?1) and Slinger seabream (5.21 μg g?1) while Pb concentrations ranged from a high of 8.44 μg g?1 in Horse mackerel to 1.09 μg g?1 in Catface rockcod. However, the estimated potential health risks from fish consumption as determined by the target hazard quotient (THQ) and hazard index (HI) were significantly lower than 1, implying that metals were not present in sufficiently high quantities to be of any health and/or food and security concern in the studied fishes. 相似文献
167.
Katrine A. Gorham Nicola J. Blake Richard A. VanCuren Henry E. Fuelberg Simone Meinardi Donald R. Blake 《Atmospheric environment (Oxford, England : 1994)》2010,44(19):2271-2279
We present a study of the seasonal and diurnal variability of carbon monoxide and selected volatile organic compounds in the Los Angeles area. Measurements were made during four different nine-day field campaigns in April/May, September, and November, 2007, and February, 2008, at the Mt. Wilson sampling site, which is located at an elevation of approximately 1700 m in the San Gabriel Mountains overlooking Pasadena and the Los Angeles basin. The results were used to characterize the Mt. Wilson site as a representative location for monitoring integrated Los Angeles basin emissions, and, by reference to carbon monoxide emissions, to estimate average annual emissions. The considerable seasonal variability of many hydrocarbons, in both their measured mixing ratios and their relationship to carbon monoxide, was indicative of variable source strengths. Most interestingly, perturbation of C4 hydrocarbon ratios suggested an enhanced role for chlorine chemistry during the month of September, likely as the result of Los Angeles’ coastal location. Such coastal influence was confirmed by observations of enhanced mixing ratios of marine halocarbons, as well as air mass back trajectories. 相似文献
168.
Emma L. Yates Richard G. Derwent Peter G. Simmonds Brian R. Greally Simon O’Doherty Dudley E. Shallcross 《Atmospheric environment (Oxford, England : 1994)》2010,44(23):2705-2713
Continuous in-situ measurements of NMHCs at Mace Head, Ireland during two full annual cycles from January 2005 to January 2007 were used to investigate NMHC emission sources and transport including dilution and photochemical oxidation. The Mace Head research station is ideally located to sample a wide range of air masses including polluted European transport, clean North Atlantic and Arctic air masses and the ultra-clean, Southern Atlantic air masses. The variety in air mass sampling is used to investigate interaction of emissions, transport, dilution and photochemistry. Variability of long-lived hydrocarbon ratios is used to assess and estimate typical transport times from emission source to the Mace Head receptor. Seasonality in the ratios of isomeric alkane pairs (for butane and pentanes) are used to assess the effects of atmospheric transport and photochemical ageing. Finally, the natural logarithms of NMHC ratios are used to assess photochemical oxidation. 相似文献
169.
Jasper Lewis Russell De Young Richard Ferrare D. Allen Chu 《Atmospheric environment (Oxford, England : 1994)》2010,44(35):4510-4520
Aerosol distributions from two aircraft lidar campaigns conducted in the California Central Valley are compared in order to identify seasonal variations. Aircraft lidar flights were conducted in June 2003 and February 2007. While the ground PM2.5 (particulate matter with diameter ≤ 2.5 μm) concentration was highest in the winter, the aerosol optical depth (AOD) measured from the MODIS and lidar instruments was highest in the summer. A multiyear seasonal comparison shows that PM2.5 in the winter can exceed summer PM2.5 by 68%, while summer AOD from MODIS exceeds winter AOD by 29%. Warmer temperatures and wildfires in the summer produce elevated aerosol layers that are detected by satellite measurements, but not necessarily by surface particulate matter monitors. Temperature inversions, especially during the winter, contribute to higher PM2.5 measurements at the surface. Measurements of the mixing layer height from lidar instruments provide valuable information needed to understand the correlation between satellite measurements of AOD and in situ measurements of PM2.5. Lidar measurements also reflect the ammonium nitrate chemistry observed in the San Joaquin Valley, which may explain the discrepancy between the MODIS AOD and PM2.5 measurements. 相似文献
170.
Henrieta Dulaiova Richard Camilli Matthew A. Charette 《Journal of environmental radioactivity》2010,101(7):553-8921
We constructed a survey system of radon/methane/nitrate/salinity to find sites of submarine groundwater discharge (SGD) and groundwater nitrate input. We deployed the system in Waquoit Bay and Boston Harbor, MA where we derived SGD rates using a mass balance of radon with methane serving as a fine resolution qualitative indicator of groundwater. In Waquoit Bay we identified several locations of enhanced groundwater discharge, out of which two (Childs and Quashnet Rivers) were studied in more detail. The Childs River was characterized by high nitrate input via groundwater discharge, while the Quashnet River SGD was notable but not a significant source of nitrate. Our radon survey of Boston Harbor revealed several sites with significant SGD, out of these Inner Harbor and parts of Dorchester Bay and Quincy Bay had groundwater fluxes accompanied by significant water column nitrogen concentrations. The survey system has proven effective in revealing areas of SGD and non-point source pollution. 相似文献