全文获取类型
收费全文 | 7043篇 |
免费 | 62篇 |
国内免费 | 35篇 |
专业分类
安全科学 | 200篇 |
废物处理 | 304篇 |
环保管理 | 585篇 |
综合类 | 1172篇 |
基础理论 | 1763篇 |
环境理论 | 7篇 |
污染及防治 | 2151篇 |
评价与监测 | 558篇 |
社会与环境 | 369篇 |
灾害及防治 | 31篇 |
出版年
2023年 | 67篇 |
2022年 | 141篇 |
2021年 | 162篇 |
2020年 | 86篇 |
2019年 | 97篇 |
2018年 | 225篇 |
2017年 | 250篇 |
2016年 | 309篇 |
2015年 | 232篇 |
2014年 | 318篇 |
2013年 | 562篇 |
2012年 | 376篇 |
2011年 | 452篇 |
2010年 | 307篇 |
2009年 | 267篇 |
2008年 | 428篇 |
2007年 | 391篇 |
2006年 | 320篇 |
2005年 | 245篇 |
2004年 | 223篇 |
2003年 | 210篇 |
2002年 | 184篇 |
2001年 | 115篇 |
2000年 | 86篇 |
1999年 | 65篇 |
1998年 | 43篇 |
1997年 | 35篇 |
1996年 | 42篇 |
1995年 | 54篇 |
1994年 | 49篇 |
1993年 | 30篇 |
1992年 | 40篇 |
1991年 | 41篇 |
1990年 | 32篇 |
1989年 | 31篇 |
1988年 | 28篇 |
1987年 | 24篇 |
1986年 | 36篇 |
1985年 | 29篇 |
1984年 | 31篇 |
1983年 | 19篇 |
1982年 | 34篇 |
1981年 | 26篇 |
1980年 | 25篇 |
1979年 | 28篇 |
1978年 | 21篇 |
1977年 | 24篇 |
1976年 | 24篇 |
1975年 | 20篇 |
1966年 | 18篇 |
排序方式: 共有7140条查询结果,搜索用时 218 毫秒
61.
Philippe Crabbé 《Environmental monitoring and assessment》1992,20(2-3):249-252
62.
Prohaska T Quétel CR Hennessy C Liesegang D Papadakis I Taylor PD Latkoczy C Hann S Stingeder G 《Journal of environmental monitoring : JEM》2000,2(6):613-620
Many fields in environmental analytical chemistry deal with very low limits and thresholds as set by governmental legislations or transnational regulations. The need for the accuracy, comparability and traceability of analytical measurements in environmental analytical chemistry has significantly increased and total uncertainties are even asked for by accreditation bodies of environmental laboratories. This paper addresses achieving these goals to guarantee accuracy, quality control, quality assurance or validation of a method by means of certified reference materials. The assessment of analytical results in certified reference materials must be as accurate as possible and every single step has to be fully evaluated. This paper presents the SI-traceable certification of Cu, Cr, Cd and Pb contents in geological and environmentally relevant matrices (three sediments and one fly ash sample). Certification was achieved using isotope dilution (ID) ICPMS as a primary method of measurement. In order to reduce significantly the number of analytical steps and intermediate samples a multiple spiking approach was developed. The full methodology is documented and total uncertainty budgets are calculated for all certified values. A non-element specific sample digestion process was optimised. All wet chemical digestion methods examined resulted in a more or less pronounced amount of precipitate. It is demonstrated that these precipitates originate mainly from secondary formation of fluorides (essentially CaF2) and that their formation takes place after isotopic equilibration. The contribution to the total uncertainty of the final values resulting from the formation of such precipitates was in general < 0.1% for all investigated elements. Other sources of uncertainty scrutinised included the moisture content determination, procedural blank determination, cross-contamination from the different spike materials, correction for spectral interferences, instrumental background and deadtime effects, as well as the use of either certified values or IUPAC data in the IDMS equation. The average elemental content in the sediment samples was 30-130 micrograms g-1 for Pb, 0.5-3 micrograms g-1 for Cd and 50-70 micrograms g-1 for Cu. Cr was measured in one sample and was about 60 micrograms g-1. The concentrations in the fly ash sample were up to 2 orders of magnitude higher. Expanded uncertainty for the investigated elements was about 3% (coverae factor k = 2) except for Cr, (measured by high resolution ICPMS), for which the expanded uncertainty was about 7% (k = 2). 相似文献
63.
64.
Using environmental stressor information to predict the ecological status of Maryland non-tidal streams as measured by biological indicators 总被引:4,自引:0,他引:4
Vølstad JH Roth NE Mercurio G Southerland MT Strebel DE 《Environmental monitoring and assessment》2003,84(3):219-242
In Maryland, U.S., an interim framework has recentlybeen developed for using biologically based thresholds, or `biocriteria', to assess the health of nontidal streams statewide at watershed scales. The evaluation of impairment is based on indices of biological integrity from the Maryland Biological Stream Survey (MBSS). We applied logistic regression to quantify how the biotic integrity of streams at a local scale is affected by cumulative effects resulting from catchment land uses, point sources, and nearby transmission line rights-of-way. Indicators for land use were developed from the remote sensing National Land Cover Data and applied at different scales. We determined that the risk of local impairment in nontidal streams rapidly increases with increased urban land use in the catchment area. The average likelihood of failing biocriteria doubled with every 10% points increment in urban land, thus an increase in urban land use from 0 to 20% quadruples the risk of impairment. For the basins evaluated in this study, catchments with more than 40–50% urban land use had greater than 80% probability of failing biocriteria, on average. Inclusion of rights-of-way and point sources in the model did not significantly improve the fit for this data set, most likely because of their low numbers. The overall results indicate that our predictive modeling approach can help pinpoint stream ecosystems experiencing or vulnerable to degradation. 相似文献
65.
Using existing monitoring data, the present study attempts to characterize spatial patterns of surface water nutrients in the Baltic Sea. The analysis was made for two different spatial scales, differences between and within sub-basins.Non-parametric methods were chosen to reduce problems with the distributional properties of the data. By dividing the data into four seasons care was taken as to seasonality. To avoid bias due to different laboratory analysis, only data from Nordic countries were used, whose results did not apparently depart from each other. Bias due to different sampling frequency was another problem. This was reduced by using only the last observation in each season for every station and year.The results suggested differences in the nutrient concentrations between basins. The two northernmost basins (Bothnian Bay and Bothnian Sea) had lower phosphate concentrations and higher silicate concentrations compared to the rest of the Sea. Bothnian Bay and the Gulf of Finland had higher nitrate concentrations.The concentration structure within basins was studied using transects in both latitudinal and longitudinal direction. A gradient for phosphate and nitrate was found in the Gulf of Finland, with lower concentrations at the mouth. The Bothnian Sea showed lower concentrations in the middle of the basin compared to the coasts. The highest concentrations of phosphate were found close to the Finnish coast and for silicate the highest concentrations were located near the Swedish coast. It was not possible to study variation in the west-east direction within the Baltic proper, due to data shortage. For the transects in the north-south direction no differences were detected for nitrate and silicate. Phosphate gave one significant result during autumn for the transect in the eastern part of the Baltic proper.This study revealed several problems associated with the data available. Uneven sampling in space and time put severe constraints on the study. A better design of the monitoring program is suggested, where spatial properties are considered explicitly. Revision of the program in this direction is needed for reasonable calculation of total amounts and concentrations representative for a basin. 相似文献
66.
C. K. Jørgensen 《Die Naturwissenschaften》1980,67(4):188-189
67.
Frank Wania Yushan Su 《Ambio-人类环境杂志》2004,33(3):145-152
由于有广泛的理化特性,多氯联苯(PCBs)在全球分馏假设求导中担任着重要角色,这种假设预测持久性有机污染混合物的组成随纬度产生变化.最新的历史排放估计、内部一致的特性数据集和按气候带平均的全球命运和运输模型结合在一起允许把PCBs所经历的成分转移作为环境区划、纬度和时间的一个函数的定量调查.模型模拟复制出纬度越高在大气和土壤中所观察到的较轻PCB同类物的相对丰度就越高,并量化了分割、持久性和排放在建立PCB格局过程中的相对重要性.组成变化不仅与倒转的浓度剖面一致(北极区浓度高于低纬度区)也与全球分馏一致,但只与向北转移的全球PCB存量的较小部分一致. 相似文献
68.
69.
Dr. C. Dawn DeLozier-Blanchet Eric Engel Philippe Extermann Béatrice Pastori 《黑龙江环境通报》1988,8(4):281-286
Cytogenetic study of chorionic villi sampled because of advanced maternal age revealed, after overnight culture, an apparently non-mosaic trisomy 7. Amniocentesis showed exclusively normal mitoses, and the pregnancy continued normally. One hundred mitoses from cord blood of the normal newborn revealed a non-mosaic 46,XX complement. No cells with a proven trisomy 7 were found in cultures from either of two biopsies of the morphologically normal placenta, but the peripheral biopsy showed in multiple cultures an abnormal clone: 47,XX, + 20,-2,-21, + t(2;21)(p13;q22). To our knowledge, this is the first case of non-mosaic trisomy 7 detected on CVS which has had follow-up studies of amniotic fluid, cord blood, and term placenta. 相似文献
70.
Dr Claire Julian-Reynier Genevieve Macquart-Moulin Jean-Paul Moatti Anderson Loundou Yvette Aurran Françoise Chabal Ségolene Aymé 《黑龙江环境通报》1993,13(7):613-627
The objective of this study was to explore women's attitudes towards prenatal diagnosis of trisomy 21 and to examine some of the factors possibly responsible for these attitudes before implementing in real practice serological screening of pregnant women at risk for trisomy 21. We carried out a telephone survey on a representative sample of women who had recently had a normal livebirth delivery in the Marseille district in 1990. The participation rate was 80 per cent and the average age of the mothers was 28-9 years. Among the 514 women interviewed, 78 per cent stated that they would ask for an amniocentesis for a 1 per cent risk of trisomy 21 at their next pregnancy. When adjusting for confounding factors, the decision to have or not to have an amniocentesis was found to depend not only on the women's attitude towards induced abortion, but also on their understanding of the risk involved and on the social context (knowing a handicapped child, discussion with the father). It also depended on the women's age and on what they knew about amniocentesis from the medical point of view. The risk of miscarriage can influence a woman's choice but this objection was not found to affect the women's decisions significantly in our survey. The data showed the existence of a high potential demand for fetal karyotyping. 相似文献