全文获取类型
收费全文 | 1600篇 |
免费 | 98篇 |
国内免费 | 546篇 |
专业分类
安全科学 | 49篇 |
废物处理 | 34篇 |
环保管理 | 190篇 |
综合类 | 907篇 |
基础理论 | 291篇 |
污染及防治 | 510篇 |
评价与监测 | 224篇 |
社会与环境 | 35篇 |
灾害及防治 | 4篇 |
出版年
2024年 | 3篇 |
2023年 | 47篇 |
2022年 | 50篇 |
2021年 | 55篇 |
2020年 | 70篇 |
2019年 | 78篇 |
2018年 | 55篇 |
2017年 | 51篇 |
2016年 | 79篇 |
2015年 | 84篇 |
2014年 | 70篇 |
2013年 | 125篇 |
2012年 | 114篇 |
2011年 | 149篇 |
2010年 | 111篇 |
2009年 | 170篇 |
2008年 | 162篇 |
2007年 | 125篇 |
2006年 | 85篇 |
2005年 | 81篇 |
2004年 | 59篇 |
2003年 | 70篇 |
2002年 | 39篇 |
2001年 | 68篇 |
2000年 | 46篇 |
1999年 | 39篇 |
1998年 | 35篇 |
1997年 | 28篇 |
1996年 | 27篇 |
1995年 | 11篇 |
1994年 | 15篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 10篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有2244条查询结果,搜索用时 828 毫秒
641.
Nonpoint-Source Agricultural Hazard Index: A Case Study of the Province of Cremona, Italy 总被引:1,自引:0,他引:1
This paper reports the results of a study aimed at the evaluation of the hazard level of farming activities in the province
of Cremona, Italy, with particular reference to groundwater. The applied methodology employs a parametric approach based on
the definition of potential hazard indexes (nonpoint-source agricultural hazard indexes, NPSAHI). Two categories of parameters
were considered: the hazard factors (HF), which represent all farming activities that cause or might cause an impact on groundwater
(use of fertilizers and pesticides, application of livestock and poultry manure, food industry wastewater, and urban sludge),
and the control factors (CF), which adapt the hazard factor to the characteristics of the site (geographical location, slope,
agronomic practices, and type of irrigation). The hazard index (HI) can be calculated multiplying the hazard factors by the
control factors and, finally, the NPSAHI are obtained dividing HI into classes on a percentile basis using a scale ranging
from 1 to 10. Organization, processing, and display of all data layers were performed using the geographical information system
(GIS) ArcView and its Spatial Analyst extension. Results show that the potential hazard of groundwater pollution by farming
activities in the province of Cremona falls mainly in the fifth class (very low hazard). 相似文献
642.
Ester Heath Nives Ogrinc Jadran Faganeli Stefano Covelli 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):605-614
To reconstruct a history of polycyclic aromatic hydrocarbon (PAH) pollution in the Gulf of Trieste, one of the largest urbanized
areas in the Adriatic Sea, we analyzed three long sediment cores collected between 1996 and 1997. Concentrations of total
PAHs, the sum of 16 PAH compounds and six of their methylated analogues, in all three cores show a decrease from 600–800 ng
g−1, at the surface, to levels below 250 ng g−1 in deepest layers (down to 3 m). The same trend was shown with separate representative pyrogenic PAHs (pyrene, benzofluoranthene
and phenanthrene). Using Hg as a recent geochronological tracer, we observe an increasing input of PAHs since the beginning
of the 20th Century and, especially, after the Second World War coinciding with increasing industrialization and urbanization
of the region. This correlation is supported by PAH ratios that are indication of combustion processes and represent a marker
for anthropogenic inputs. No correlation exists between PAHs and black carbon within the core profiles, indicating two different
fractions of the ‘black carbon continuum’. 相似文献
643.
This article suggests that Asia’s groundwater socio‐ecology is at an impasse. Rapid growth in groundwater irrigation in South Asia and the North China plains during the period 1970–95 has been the main driver of the agrarian boom in these regions. India, Pakistan, Bangladesh and China account for the bulk of the world’s use of groundwater in agriculture. On the plus side, groundwater development has provided sustenance to agrarian economies and millions of rural livelihoods. On the downside, it has created chronic problems of resource depletion and quality deterioration. While problems of groundwater depletion, pollution and quality deterioration are indeed serious, so are the consequences of the degradation of the resource for those that have come to precariously depend upon groundwater irrigation. Three problems currently afflict groundwater use: depletion due to overdraft; water logging and salinization; and pollution due to agricultural, industrial and other human activity. The pathology of the decline in groundwater socio‐ecology reflects a remarkably similar pattern across regions. The critical issue for Asia now is: what might be done to sustain and revive these groundwater socio‐ecologies vital to the region’s economy? This article reviews a variety of techno‐institutional approaches. However, transposing lessons from the industrialized world uncritically in the Asian context may not work. A more nuanced understanding of the peculiarities of Asia’s groundwater socio‐ecology is needed. 相似文献
644.
J.??áslavskyEmail author P.?Kotla?íková K.?Bene?ová 《Environmental Chemistry Letters》2004,2(2):89-92
Semipermeable membrane devices (SPMDs) are nowadays used as passive samplers of organic pollutants. The knowledge of the sampling rate values (RS) of each substance trapped on membranes is necessary to calculate their average concentration. Here we calculate RS values for 16 polycyclic aromatic hydrocarbons using the comparison of active sampling method results and the amounts sequestered by SPMDs at varying exposure times.Selected article from the Regional Symposium on Chemistry and Environment, Krusevac, Serbia, June 2003, organized by Dr. Branimir Jovancicevic. 相似文献
645.
Fernández Pilar Rose Neil L. Vilanova Rosa M. Grimalt Joan O. 《Water, Air, & Soil Pollution: Focus》2002,2(2):261-274
Spheroidal carbonaceous particles (SCP) and polycyclicaromatic hydrocarbons (PAH) have been measured in the dated sediment cores of 10 remote lakes distributed across Europe. The geographic trends were evaluated by examination of the superficial sediment fluxes and total sediment inventories. The highest levels of both markers were observed in the Eastern European lakes whereas the minimal values corresponded to the lake located in the Arctic. However, this SCP-PAH correlation was not observed after exclusion of the end member lakes from the series. The temporal trends of both pollutant markers are consistent with the history of pyrolytic emissions over Europe. However, the downcore SCP distributions are shorter than the PAH profiles in nearly all lakes. The differences are probably related to the different size particle fractions involved in the measurement of each marker, >5 and >1 m for SCP and PAH, respectively. Thus, the two proxies probably reflect pollution inputs from closer (SCP) and more distant sites (PAH). 相似文献
646.
Diem JE 《Environmental management》2002,29(3):373-384
This paper examines possible ozone-induced foliar injury to ponderosa pine areas in the Rincon Mountains of southern Arizona
from 1972 to 1992. Spatiotemporal differences in a satellite-derived vegetation index (VI) are examined with respect to antecedent
moisture conditions, temporal variations in ozone exposure levels, and measured foliar injury values from 1985. Seasonal ozone
exposure levels (SUM60 and W126) increased from 1982 to 1998 and were significantly correlated (r = 0.49 and 0.53, α= 0.05) with annual population totals in the Tucson area. Extensive masking of satellite images from 1972, 1986,
and 1992 resulted in two optimal change detection areas, with one site, TVWMica, exposed mostly to the Tucson air pollution
plume, while the other site, EMica, was more protected from Tucson-derived pollution. An overall increase in VI from 1972
to 1992 at both sites appears to have been caused by an increase in moisture availability. Larger foliar injury values in
1985 were associated with a smaller increase in VI (i.e., a smaller increase in green leaf biomass) from 1972 to 1986. From
1972 to 1986 and from 1986 to 1992, VI values at TV/WMica increased at a slower rate compared to those at EMica. The reduced
increase in “green-up” may have been caused partially by ozone-induced foliar injury and resulting decreases in green leaf
biomass. However, these spatial differences in VI values may have also been caused by a number of other factors. Results nevertheless
reveal the strong possibility of distinct, topographically based, spatial variations in ozone-induced foliar injury within
the Rincons. 相似文献
647.
K. Abbaspour V. Matta P. Huggenberger C. A. Johnson 《Journal of contaminant hydrology》2000,40(4):196
The investigation of contaminated sites is usually a long and expensive process. It is therefore desirable to use a combination of methodologies in an integrative approach that can reduce redundant information gathering. The objective of this study was to examine the usefulness of 2 non-intrusive exploration techniques in a contaminated site investigation. Borehole positioning based on geophysical measurements was compared to positioning based on the Bayesian expert system for flow-field modeling. The goal set at the field site was the assessment of the type and load of contaminants transported from the landfill site to the adjacent aquifer and the extent of leachate plumes within the groundwater. The two methods made different demands on information gathering and were found to be complementary. The geophysical approach focused attention on the waste compartments at the site and on mixing plumes in the adjacent aquifer but could not, without prior information, provided information on the flow field. The Bayesian approach to flow-field modeling determined areas of greatest model uncertainty at the model boundaries. The model highlighted areas of greatest uncertainty that might otherwise have been overlooked and provided information on the most likely mean direction of the leachate plumes. It was concluded that both methods contribute to a site investigation and should be used before additional drilling is carried out. 相似文献
648.
649.
对杭州湾潮滩表层沉积物样品中的多环芳烃(PAHs)进行了定量分析.结果表明,沉积物中PAHs总含量范围为45.78~849.93ng/g.PAHs的空间分布总体呈现钱塘江杭州河段>杭州湾南岸>杭州湾北岸.PAHs含量分布与有机碳(TOC)含量存在良好的线性关系,受人类活动和水动力条件的影响较大.样品中PAHs的燃烧来源所占的比重较大,呈现出油料燃烧与木材、煤燃烧的混合污染来源特征.该地区表层沉积物样品中的PAHs尚未对生物造成显著的负面影响. 相似文献
650.