全文获取类型
收费全文 | 19050篇 |
免费 | 650篇 |
国内免费 | 3303篇 |
专业分类
安全科学 | 721篇 |
废物处理 | 1288篇 |
环保管理 | 1907篇 |
综合类 | 6703篇 |
基础理论 | 4535篇 |
环境理论 | 2篇 |
污染及防治 | 4494篇 |
评价与监测 | 1475篇 |
社会与环境 | 1513篇 |
灾害及防治 | 365篇 |
出版年
2024年 | 29篇 |
2023年 | 188篇 |
2022年 | 524篇 |
2021年 | 500篇 |
2020年 | 459篇 |
2019年 | 377篇 |
2018年 | 1814篇 |
2017年 | 1810篇 |
2016年 | 1642篇 |
2015年 | 696篇 |
2014年 | 718篇 |
2013年 | 915篇 |
2012年 | 1254篇 |
2011年 | 2116篇 |
2010年 | 1305篇 |
2009年 | 1219篇 |
2008年 | 1553篇 |
2007年 | 1753篇 |
2006年 | 532篇 |
2005年 | 391篇 |
2004年 | 320篇 |
2003年 | 396篇 |
2002年 | 432篇 |
2001年 | 261篇 |
2000年 | 286篇 |
1999年 | 242篇 |
1998年 | 229篇 |
1997年 | 182篇 |
1996年 | 172篇 |
1995年 | 153篇 |
1994年 | 124篇 |
1993年 | 107篇 |
1992年 | 83篇 |
1991年 | 52篇 |
1990年 | 32篇 |
1989年 | 18篇 |
1988年 | 27篇 |
1987年 | 3篇 |
1986年 | 12篇 |
1985年 | 3篇 |
1984年 | 20篇 |
1983年 | 13篇 |
1982年 | 17篇 |
1981年 | 5篇 |
1978年 | 6篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
421.
The inhibition and dispersion of polyepoxysuccinate (PESA, self-manufactured) to inorganic scale was evaluated by scale static beaker test to CaC03 and Ca3(P04)2, stability test to zinc salt, and dispersion test to ferric oxide. The experimental results demonstrated that PESA functioned excellent scale inhibition to CaC03 and Ca3(P04)2, good stability to zinc salt and special dispersion to ferric oxide. Under the water with hardness 500-1200 mg/L, alkalinity 1000 mg/L, and dosage of PESA 31.2 mg/L, PESA scale inhibition ratio reached more than 85.0%. At dosage of PESA 20.8 mg/L inhibition ratio on calcium phosphate reached 38.9%, at optimum dosage of PESA 9.1 mg/L, the stability ratio was up to 96.1%; while at dosage of PESA 3.6 mg/L, transmittance ratio reached 64.4%. Therefore, PESA can be considered a soluble, high effective and versatile inhibitor. 相似文献
422.
The Role of Disaggregation of Asset Values in Flood Loss Estimation: A Comparison of Different Modeling Approaches at the Mulde River,Germany 总被引:3,自引:0,他引:3
Anja Wünsch Ulrich Herrmann Heidi Kreibich Annegret H. Thieken 《Environmental management》2009,44(3):524-541
In loss estimation there is a spatial mismatch of hazard data that are commonly modeled on an explicit raster level and exposure
data that are often available only for aggregated administrative units. Usually disaggregation methods that use ancillary
information to distribute lumped exposure data in a finer spatial resolution help to bridge this gap. However, the actual
influence of different mapping techniques and ancillary data on the final loss estimation has not been analyzed yet. In this
paper three methods are applied to disaggregate residential building assets using two kinds of land use/land cover (LULC)
data. The resulting disaggregated assets are validated and compared using census data of the residential building number on
the community and constituency level. In addition, the disaggregated assets are taken to estimate residential building losses
due to the flood in August 2002 in 21 municipalities on the River Mulde in Saxony, Germany. Losses are calculated with the
help of four loss models. In general, disaggregation helps to decrease the error variance within the loss estimation. It must,
however, be stated that the application of sophisticated disaggregation methods does not lead to significant improvements
compared to the straightforward binary method. Therefore more effort should instead be put into the provision of high-resolution
LULC data. Finally, the remaining uncertainties in loss estimation are high and demand further improvements in all modeling
aspects. 相似文献
423.
424.
Adaptive maritime spatial planning (MSP) uses monitoring and evaluation of the effectiveness of spatial and temporal management
measures to promote understanding and improve planning and decision-making. An adaptive approach to MSP involves exploring
alternative ways to meet management objectives, predicting the outcomes of alternative management measures, implementing one
or more of these alternative management measures, monitoring to learn about the effects of management measures, and then using
the results to update knowledge and adjust management actions. A monitoring and evaluation plan should be designed to be both
cost effective and comprehensive. The process of setting and assessing performance metrics requires that the ecological and
socio-economic objectives of the spatial management plan must be clearly stated up front for management actions to reflect
those objectives accurately. To evaluate the effectiveness of a MSP plan, a range of ecological, socio-economic and institutional
indicators need to be developed and monitored. 相似文献
425.
In this paper, we explore a range of concerns that arise in measuring short-term effects of ozone on health. In particular,
we tackle the problem of measuring exposure using alternative daily measures of ozone derived from hourly concentrations.
We adopt the exposure paradigm of Chiogna and Bellini (Environmetrics 13:55–69, 2002) extending it to ozone concentrations,
and we compare its performances with respect to traditional exposure measures by exploiting model selection. To investigate
the stability of model selection, we then apply the idea of bootstrapping the modelling process. 相似文献
426.
Salinity levels vary spatially in coastal areas, depending on proximity to freshwater sources, and may also be slowly decreasing
as a result of anthropogenic climatic changes. The impact of salinity on host–parasite interactions is potentially a key regulator
of transmission processes in intertidal areas, where trematodes are extremely common parasites of invertebrates and vertebrates.
We investigated experimentally the effects of long-term exposure to decreased salinity levels on output of infective stages
(cercariae) and their transmission success in the trematode Philophthalmus sp. This parasite uses the snail Zeacumantus subcarinatus as intermediate host, in which it asexually produces cercariae. After leaving the snail, cercariae encyst externally on hard
substrates to await accidental ingestion by shorebirds, which serve as definitive hosts. We found that at reduced salinities
(25 or 30 psu), the cercarial output of the parasite was lower, the time taken by cercariae to encyst was longer, fewer cercariae
successfully encysted and encysted parasites had lower long-term survival than at normal seawater salinity (35 psu). The strong
effect of salinity on the replication and transmission of this parasite suggests that there may be sources and sinks of transmission
to birds along coastal areas, depending on local salinity conditions. Also, unless it evolves to adapt to changing conditions,
the predicted reduction in salinity as a consequence of climate change may have negative impact on the parasite’s abundance. 相似文献
427.
Loss of zooxanthellae (dinoflagellate Symbiodinium) from corals will sometimes lead to mass mortality of corals. To detect and quantify Symbiodinium released from corals, we developed a zooxanthellae “trap” and a quantitative PCR (qPCR) system with Symbiodinium clades A–F-specific primer sets. The trap was attached to a branch or the surface of several wild stony corals, and the water
samples within the traps, including released Symbiodinium, were subjected to qPCR. All tested corals released clade C Symbiodinium at estimates of ~5,900 cells h−1 cm−2 of coral surface. Although all tested Pocillopora eydouxi harboured both clades C and D, some of these colonies released only clade C or released a lesser amount of clade D than that
in the tissues. Our Symbiodinium quantification system revealed that wild hermatypic corals constantly release Symbiodinium to the environment. Our result suggests that some corals may discharge certain clades of Symbiodinium alternatively. 相似文献
428.
429.
Derek Vollmer Maíra Ometto Bezerra Natalia Acero Martínez Octavio Rodríguez Ortiz Ivo Encomenderos Maria Clara Marques Lina Serrano-Durn Isabelle Fauconnier Raymond Yu Wang 《Ambio》2021,50(4):870
Quantitative assessments have long been used to evaluate the condition of the natural environment, providing information for standard setting, adaptive management, and monitoring. Similar approaches have been developed to measure environmental governance, however, the end result (e.g., numeric indicators) belies the subjective and normative judgments that are involved in evaluating governance. We demonstrate a framework that makes this information transparent, through an application of the Freshwater Health Index in three different river basins in Latin America. Water Governance is measured on a 0–100 scale, using data derived from perception-based surveys administered to stakeholders. Results suggest that water governance is a primary area of concern in all three places, with low overall scores (Guandu-26, Alto Mayo-38, Bogotá-43). We conclude that this approach to measuring governance at the river basin scale provides valuable information to support monitoring and decision making, and we offer suggestions on how it can be improved.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01407-8) contains supplementary material, which is available to authorized users. 相似文献
430.
Xia Chengcheng Liu Guodong Zhou Jing Meng Yuchuan Chen Ke Gu Pengfei Yang Mengxi Huang Xiaohua Mei Jie 《Environmental science and pollution research international》2021,28(30):40160-40177
Environmental Science and Pollution Research - In recent years, the development and utilization of water resources have imposed great impacts on hydrological characteristics and ecological... 相似文献