全文获取类型
收费全文 | 1305篇 |
免费 | 12篇 |
国内免费 | 16篇 |
专业分类
安全科学 | 48篇 |
废物处理 | 56篇 |
环保管理 | 186篇 |
综合类 | 255篇 |
基础理论 | 273篇 |
环境理论 | 2篇 |
污染及防治 | 325篇 |
评价与监测 | 105篇 |
社会与环境 | 78篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 15篇 |
2022年 | 26篇 |
2021年 | 28篇 |
2020年 | 17篇 |
2019年 | 21篇 |
2018年 | 36篇 |
2017年 | 28篇 |
2016年 | 33篇 |
2015年 | 32篇 |
2014年 | 46篇 |
2013年 | 60篇 |
2012年 | 63篇 |
2011年 | 76篇 |
2010年 | 49篇 |
2009年 | 70篇 |
2008年 | 59篇 |
2007年 | 77篇 |
2006年 | 57篇 |
2005年 | 56篇 |
2004年 | 57篇 |
2003年 | 44篇 |
2002年 | 43篇 |
2001年 | 37篇 |
2000年 | 19篇 |
1999年 | 16篇 |
1998年 | 26篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 19篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 16篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 5篇 |
1978年 | 4篇 |
1974年 | 4篇 |
1972年 | 4篇 |
1969年 | 3篇 |
1968年 | 4篇 |
1965年 | 4篇 |
1962年 | 3篇 |
排序方式: 共有1333条查询结果,搜索用时 437 毫秒
341.
Hyland JL Balthis WL Engle VD Long ER Paul JF Summers JK Van Dolah RF 《Environmental monitoring and assessment》2003,81(1-3):149-161
Synoptic data on concentrations of sediment-associated chemical contaminants and benthic macroinfaunal community structure were collected from 1,389 stations in estuaries along the U.S. Atlantic and Gulf of Mexico coasts as part of the nationwide Environmental Monitoring and Assessment Program (EMAP). These data were used to develop an empirical framework for evaluating risks of benthic community-level effects within different ranges of sediment contamination from mixtures of multiple chemicals present at varying concentrations. Sediment contamination was expressed as the mean ratio of individual chemical concentrations relative to corresponding sediment quality guidelines (SQGs), including Effects Range-Median (ERM) and Probable Effects Level (PEL) values. Benthic condition was assessed using diagnostic, multi-metric indices developed for each of three EMAP provinces (Virginian, Carolinian, and Louisianian). Cumulative percentages of stations with a degraded benthic community were plotted against ascending values of the mean ERM and PEL quotients. Based on the observed relationships, mean SQG quotients were divided into four ranges corresponding to either a low, moderate, high, or very high incidence of degraded benthic condition. Results showed that condition of the ambient benthic community provides a reliable and sensitive indicator for evaluating the biological significance of sediment-associated stressors. Mean SQG quotients marking the beginning of the contaminant range associated with the highest incidence of benthic impacts (73–100% of samples, depending on the province and type of SQG) were well below those linked to high risks of sediment toxicity as determined by short-term toxicity tests with single species. Measures of the ambient benthic community reflect the sensitivities of multiple species and life stages to persistent exposures under actual field conditions. Similar results were obtained with preliminary data from the west coast (Puget Sound). 相似文献
342.
Sutton MA Asman WA Ellermann T Van Jaarsveld JA Acker K Aneja V Duyzer J Horvath L Paramonov S Mitosinkova M Tang YS Achermann B Gauger T Bartniki J Neftel A Erisman JW 《Environmental monitoring and assessment》2003,82(2):149-185
In the context of international efforts to reduce the impactsof atmospheric NH3 and NH4
+ (collectively, NHx), it is important to establish the link between NH3emissions and monitoring of NHx concentrations and deposition. This is equally relevant to situations where NH3emissions changes are certain (e.g. due to changed source sectoractivity), as to cases where NH3 abatement technologies havebeen implemented. Correct interpretation of adequate atmosphericmeasurements is essential, since monitoring data provide the onlymeans to evaluate trends in regional NH3 emissions.These issues have been reviewed using available measurements and modelling from nine countries. In addition to historic datasets,the analysis here considers countries where NH3 source sector activity changed (both increases and decreases) and countries where NH3 abatement policies have been implemented.In The Netherlands an `ammonia gap' was identified between the expected reduction and results of monitoring, and was attributedinitially to ineffectiveness of the abatement measures. The analysis here for a range of countries shows that atmospheric interactions complicate the expected changes, particularly sinceSO2 emissions have decreased at the same time, while at manysites the few years of available data show substantial inter-annual variation. It is concluded that networks need to beestablished that speciate between NH3 and aerosol NH4
+, in addition to providing wet deposition, and sample at sufficient sites for robust regional estimates to be established. Such measurements will be essential to monitor compliance of the international agreements on NH3 emission abatement. 相似文献
343.
De Rooij C Thompson RS Garny V Lecloux A van Wijk D 《Environmental monitoring and assessment》2004,97(1-3):3-22
This risk assessment on dichloromethane was carried out specifically for the marine environment, following methodology given in the EU risk assessment Regulation (1488/94) and Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of 'predicted environmental concentrations' (PEC) to 'predicted no-effect concentrations' (PNEC) for the marine aquatic environment. In total, 23 studies for fish, 17 studies for invertebrates and 6 studies for algae were evaluated. Both acute and chronic toxicity studies were taken into account and appropriate assessment factors used to define a PNEC value of 830 microg/l. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1983--1995) support a typical PEC for dichloromethane lower than 0.2 microg/l and a worst case PEC of 13.6 microg/l. Dichloromethane is not a 'toxic, persistent and liable to bioaccumulate' substance sensu the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). The calculated PEC/PNEC ratios give margins of 60 to 4000 between the PNEC and PEC, dilution within the sea would further increase these margins. It can be concluded that the present use of dichloromethane does not present a risk to the marine aquatic environment. 相似文献
344.
345.
William H. Parker Annette Van Niejenhuis Joell Ward 《Environmental monitoring and assessment》1996,39(1-3):589-599
A preliminary study was undertaken to reveal ecotypic differentiation in jack pine and black spruce corresponding to ecological land classification groups. Seed sources of jack pine (64) and black spruce (68) from northwestern Ontario were classified according to Vegetation Types (V-Types) and Soil Types (S-Types) defined by the Forest Ecosystem Classification (FEC) developed by the Ontario Ministry of Natural Resources and Forestry Canada for northwestern Ontario. Two short-term common garden field trials and a greenhouse trial were established for each species. Significant differences were present among ecological groupings of seed sources for both species. These differences were expressed according to V-Types and S-Types based on first, second, and third year heights as well as needle flushing dates for jack pine and second year growth increments for black spruce. Rank differences among the groups based on FEC V-Types and S-Types were generally consistent for each of the two species although certain groups showed rank reversals at the two field trials. Apparently, selection pressures corresponding to different FEC V-Types and S-Types have resulted in a detectable pattern of adaptive variation for both jack pine and black spruce in northwestern Ontario. However, the management implications for these two species are uncertain since additional tests are required to verify these results. 相似文献
346.
Surveys were completed on Tutuila Island, American Samoa, to characterize reef development and assess the impacts of non-point source pollution on adjacent coral reefs at six sites. Multivariate analyses of benthic and coral community data found similar modern reef development at three locations; Aoa, Alofau, and Leone. These sites are situated in isolated bays with gentle sloping foundations. Aoa reefs had the highest estimates of crustose coralline algae cover and coral species richness, while Leone and Alofau showed high abundances of macroalgae and Porites corals. Aoa has the largest reef flat between watershed discharge and the reef slope, and the lowest human population density. Masefau and Fagaalu have a different geomorphology consisting of cemented staghorn coral fragments and steep slopes, however, benthic and coral communities were not similar. Benthic data suggest Fagaalu is heavily impacted compared with all other sites. Reef communities were assessed as bio-criteria indicators for waterbody health, using the EPA aquatic life use support designations of (1) fully supportive, (2) partially supportive, and (3) non-supportive for aquatic life. All sites resulted in a partially supportive ranking except Fagaalu, which was non-supportive. The results of this rapid assessment based upon relative benthic community measures are less desirable than long-term dataset analyses from monitoring programs, however it fills an important role for regulatory agencies required to report annual waterbody assessments. Future monitoring sites should be established to increase the number of replicates within each geological and physical setting to allow for meaningful comparisons along a gradient of hypothesized pollution levels. 相似文献
347.
Edith?T.?Lammerts?Van?Bueren Paul?C.?StruikEmail author 《Journal of Agricultural and Environmental Ethics》2005,18(5):479-493
In addition to obviating the use of synthetic agrochemicals and emphasizing farming in accordance with agro-ecological guidelines, organic farming acknowledges the integrity of plants as an essential element of its natural approaches to crop production. For cultivated plants, integrity refers to their inherent nature, wholeness, completeness, species-specific characteristics, and their being in balance with their (organically farmed) environment, while accomplishing their “natural aim.” We argue that this integrity of plants has ethical value, distinguishing integrity of life, plant-typic integrity, genotypic integrity, and phenotypic integrity. We have developed qualitative criteria to ethically evaluate existing practices and have applied these criteria to assess whether current plant breeding and propagation techniques violate the integrity of crop plants. This process has resulted in a design of a holistic, scientific approach of organic plant breeding and seed production. Our evaluation has met considerable criticism from mainstream (crop) scientists. We respond to the following questions: (1). Can ethics be incorporated into objective crop sciences? (2). What is the nature of the intrinsic value of plants in organic farming? We argue that criteria to take integrity into account can only be assessed from a holistic perspective and we show that a holistic approach is needed to design such ethical notions in a consistent way. The ethical notions have been further elaborated by formulating human responsibility and respect towards crop plants. Responsibility and respect can only be shown by providing crop plants the right to be nurtured and to express natural behavior at all levels of integrity. 相似文献
348.
T. Vaněk A. Nepovím R. Podlipná S. Zeman M. Vágner 《Water, Air, & Soil Pollution: Focus》2003,3(3):259-267
The phytoremediation of trinitrotoluene (TNT), nitroglycerine (NG) and pentaerytritoltetranitrate (PETN) using in vitrocultures of Rheum palmatum, Saponaria officinalisand Populus simonii were studied. All above mentioned explosives were degradated to less toxic products and finally probably bound to the cell wall or further involved in the metabolism. The formation of trinitrobenzene (TNB) during degradation of TNT which is a product of alternative degradation pathway was found too. 相似文献
349.
This study sought for national characteristics that moderate the individual‐level relationship between job characteristics and job satisfaction. Data from two distinct questionnaire surveys administered to 107,292 employees in 49 countries was analyzed by employing multilevel modeling. Results showed that the link between intrinsic job characteristics and job satisfaction is stronger in richer countries, countries with better governmental social welfare programs, more individualistic countries, and smaller power distance countries. By contrast, extrinsic job characteristics are strongly and positively related to job satisfaction in all countries. In addition, we found that intrinsic job characteristics tend to produce motivating satisfaction in countries with good governmental social welfare programs irrespective of the degree of power distance, while they do not tend to work so in countries with poor governmental social welfare programs as well as a large power distance culture. Socio‐economic and cultural approaches to explaining cross‐national variation in work motivation are discussed. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
350.
The relationship between health complaints and flexible work schedules was studied in a patient population selected by general practitioners. Four hundred and eighty patients between 20 and 60 years, currently employed or on sick leave, completed questionnaires which compiled data on their work situation, subjective physical health, psychological well‐being, and quality of sleep. Subjective health measurements were performed by using the 21‐item Subjective Health Questionnaire (VOEG). Psychological well‐being was measured by applying a selection of the Sickness Impact Profile. Duration and quality of sleep were measured through a selection of the Groningen Sleep Scale. Patients working rotating shifts, compressed weeks, and irregularly changing hours showed significantly more health complaints, more problems related to their psychological performance, and more sleeping problems than a control group of workers with non‐flexible work schedules. Patients working on temporary employment contracts reported significantly more problems with their psychological performance. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献