全文获取类型
收费全文 | 345篇 |
免费 | 6篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 14篇 |
环保管理 | 70篇 |
综合类 | 46篇 |
基础理论 | 94篇 |
污染及防治 | 84篇 |
评价与监测 | 19篇 |
社会与环境 | 11篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 8篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 10篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 13篇 |
2013年 | 27篇 |
2012年 | 6篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 12篇 |
2008年 | 17篇 |
2007年 | 16篇 |
2006年 | 16篇 |
2005年 | 18篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 11篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1964年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有356条查询结果,搜索用时 515 毫秒
91.
92.
Tran D Massabuau JC Garnier-Laplace J 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):821-826
Multi-stress situations are a major question and low-oxygenated waters (hypoxia) are a growing problem. Importantly, hypoxia stimulates the ventilatory flow rate in aquatic animals and this increases gill exposure to contaminants. Surprisingly, in the freshwater clam Corbicula fluminea, this is associated with increased bioaccumulation of uranium in gills but not in deep tissues. We searched for an explanation by analyzing hemolymph U-transport in Corbicula exposed to 0.36 μM dissolved uranium at various O2-levels for 10 days. In hypoxia, one observed an increased U concentration in the arterial hemolymph flowing from gills to tissues but this was not associated with an increased U concentration in the venous hemolymph nor in the other tissues. We conclude that the cardiac flow rate must have decreased to explain this absence of over-accumulation. In addition to its already known deleterious effects, uranium can thus deeply impair cardiac flow rate in exposed aquatic animals during multi-stress exposures. 相似文献
93.
94.
This article investigates how remotely sensed lawn characteristics, such as parcel lawn area and parcel lawn greenness, combined
with household characteristics, can be used to predict household lawn fertilization practices on private residential lands.
This study involves two watersheds, Glyndon and Baisman’s Run, in Baltimore County, Maryland, USA. Parcel lawn area and lawn
greenness were derived from high-resolution aerial imagery using an object-oriented classification approach. Four indicators
of household characteristics, including lot size, square footage of the house, housing value, and housing age were obtained
from a property database. Residential lawn care survey data combined with remotely sensed parcel lawn area and greenness data
were used to estimate two measures of household lawn fertilization practices, household annual fertilizer nitrogen application
amount (N_yr) and household annual fertilizer nitrogen application rate (N_ha_yr). Using multiple regression with multi-model inferential procedures, we found that a combination of parcel lawn area and
parcel lawn greenness best predicts N_yr, whereas a combination of parcel lawn greenness and lot size best predicts variation in N_ha_yr. Our analyses show that household fertilization practices can be effectively predicted by remotely sensed lawn indices and
household characteristics. This has significant implications for urban watershed managers and modelers. 相似文献
95.
Raymond P. Morgan II Kathleen M. Kline John B. Churchill 《Environmental monitoring and assessment》2013,185(3):2123-2137
Management of stream nutrients is becoming increasingly important in order to protect both water quality and aquatic resources throughout the USA. Using an extensive water quality database from the long-term Maryland Biological Stream Survey (MBSS), we describe nutrient relationships to landscape characteristics as total nitrogen (TN) and total phosphorus (TP) of small-order, non-tidal streams in USEPA L2 and L3 ecoregions in Maryland and by MBSS stream order at the L2 and L3 ecoregion levels. To protect stream ecosystem integrity, preliminary reference nutrient estimates (TN and TP) as percentiles (25th of all stream reaches and 75th of stream reference reaches) for the six Maryland L3 ecoregions are: Blue Ridge TN 0.29 and 0.64 mg/L, TP 0.0065 and 0.0090 mg/L; Central Appalachians TN 0.40 and 1.0 mg/L, TP 0.0060 and 0.015 mg/L; Middle Atlantic Coastal Plains TN 0.93 and 2.5 mg/L, TP 0.094 and 0.065 mg/L; Northern Piedmont TN 1.6 and 1.8 mg/L, TP 0.010 and 0.015 mg/L; Ridge and Valley TN 0.40 and 0.98 mg/L, TP 0.0063 and 0.012 mg/L; and Southeastern Plains TN 0.33 and 0.82 mg/L, TP 0.016 and 0.042 mg/L. High levels of both TN and TP are present in many streams found in non-tidal watersheds associated with all Maryland ecoregions, but are especially elevated in the Northern Piedmont and Middle Atlantic Coastal Plain ecoregions, with the latter second-order streams (average TN?>?2.9 mg/L) significantly higher than all other ecoregion–order combinations. Across all six ecoregions, mean nutrient loading for both TN and TP was generally equivalent in first-order streams to nutrient concentrations seen in both second- and third-order streams, indicating a definite need to increase efforts in preventing nutrients from entering first-order streams. Small-order stream nutrient levels are the drivers for subsequent TN and TP inputs into the upper freshwater tidal reaches of the Chesapeake Bay, resulting in a potential risk for altered estuarine ecosystems. 相似文献
96.
Arthur J. Morgan J. L. Thomas 《Journal of the American Water Resources Association》1973,9(5):884-891
ABSTRACT: There is a lamentable absence of comprehensive planning in the current cursade to improve water quality. A serious shortcoming is the lack of evaluation of the effects of waste water treatment upon environmental quality. At some point in time the public may ask what they have obtained for their money. The nature of pollution in a river basin demands a coordinated attack against it. Engineering and economic criteria suggest that a properly empowered river basin authority would be the logical organization to plan and operate a water quality management system. Several forms of such authorities have operated effectively and efficiently for many years in the United States and other industrialized countries. Examples of successful river basin authorities and their advantages and methods of operation are discussed. 相似文献
97.
98.
99.
VanWieringen LM Harrison JH Nennich T Davidson DL Morgan L Chen S Bueler M Hoisington F 《Journal of environmental quality》2005,34(1):164-173
Legislation in the United States has recently focused on improving water quality by establishing management practices that limit the quantities of nutrients entering the water supply. Timely application and quantification of the amount of manure applied throughout the grass-growing season can reduce the loss of nutrients into ground or surface water while improving the quality and quantity of grass harvested. During the 2001 and 2002 growing seasons, we measured the effects of different manure application rates on grass yields, grass nutritive value, and soil chemistry on a dairy farm. On-farm estimates of manure N were combined with yield estimates and forage quality measures to evaluate the effects of varying levels of manure application. Yield estimates, N content of grass, and the amount of N in soil and manure were monitored at each cutting for plots amended at different manure application rates. There are three major outcomes of this evaluation: (i) new grass seedings were at higher risk of elevated levels of nitrate N in forage; (ii) increased forage nitrate N at harvest was associated with malfermented silage and increased levels of ammonia N, which resulted in less efficient use of metabolizable protein for milk production; and (iii) increased understanding of N cycling between manure, soil, and plant provided an opportunity to reduce purchased fertilizer. 相似文献
100.
Andrew D. Kliskey Christopher C. Hoogsteden Richard K. Morgan 《Journal of Environmental Planning and Management》1994,37(4):431-445
The paper examines the application of a spatial‐perceptual approach to the wilderness management issue of preserving natural ecological processes while also permitting appropriate wilderness use in protected areas. An approach to delimit the spatial extent of multiple perceptions of wilderness held by backcountry users is used—the wilderness perception mapping (WPM) methodology. The results obtained from employing the WPM.methodology are considered for the North West Nelson region of New Zealand. The map product provides new and useful information that has applicability to protected areas management. The role of WPM is discussed with reference to wilderness management in North West Nelson and New Zealand, and to protected areas management in general. The study demonstrates how a technology can be combined with a critical and sensible analysis of needs and procedures to give useful results, and highlights the value of applied interdisciplinary research. 相似文献