首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   924篇
  免费   8篇
  国内免费   15篇
安全科学   27篇
废物处理   53篇
环保管理   94篇
综合类   143篇
基础理论   204篇
环境理论   2篇
污染及防治   308篇
评价与监测   55篇
社会与环境   59篇
灾害及防治   2篇
  2023年   2篇
  2022年   15篇
  2021年   17篇
  2020年   8篇
  2019年   8篇
  2018年   29篇
  2017年   36篇
  2016年   36篇
  2015年   31篇
  2014年   29篇
  2013年   94篇
  2012年   47篇
  2011年   73篇
  2010年   56篇
  2009年   56篇
  2008年   67篇
  2007年   54篇
  2006年   48篇
  2005年   31篇
  2004年   29篇
  2003年   32篇
  2002年   19篇
  2001年   9篇
  2000年   7篇
  1999年   7篇
  1998年   8篇
  1997年   9篇
  1996年   4篇
  1995年   12篇
  1994年   2篇
  1993年   4篇
  1991年   4篇
  1990年   3篇
  1987年   2篇
  1981年   3篇
  1965年   7篇
  1964年   3篇
  1963年   4篇
  1962年   9篇
  1961年   11篇
  1960年   1篇
  1958年   2篇
  1957年   1篇
  1956年   1篇
  1954年   1篇
  1947年   1篇
  1942年   1篇
  1941年   2篇
  1938年   1篇
  1932年   1篇
排序方式: 共有947条查询结果,搜索用时 171 毫秒
471.
In publicly available waste reports only the totals of waste produced for municipal, or industry waste typically feature. The types of waste generated and the generating industry sector are usually omitted. We propose the direct inputs waste estimation methodology to create a detailed estimate of municipal solid waste and industrial solid waste for an economy (including sectoral and waste type disaggregation) using a top-down estimation methodology that links the aforementioned limited publicly available waste data with an input–output table’s direct inputs (A) matrix. We then provide an application of the direct inputs waste estimation methodology upon the 2008 waste generation of Australia resulting in a 344 industry sector and 14 waste type data set. The resulting estimation gives unique insights into Australian waste generation; including the large C&I tonnages of waste estimated to be produced from the Service sectors such as the Education, Hospitality, and Health sectors as well as the large amount of food waste produced throughout the economy.  相似文献   
472.
Hydrologic modeling can be used to provide warnings before, and to support operations during and after floods. Recent technological advances have increased our ability to create hydrologic models over large areas. In the United States (U.S.), a new National Water Model (NWM) that generates hydrologic variables at a national scale was released in August 2016. This model represents a substantial step forward in our ability to predict hydrologic events in a consistent fashion across the entire U.S. Nevertheless, for these hydrologic results to be effectively communicated, they need to be put in context and be presented in a way that is straightforward and facilitates management‐related decisions. The large amounts of data produced by the NWM present one of the major challenges to fulfill this goal. We created a cyberinfrastructure to store NWM results, “accessibility” web applications to retrieve NWM results, and a REST API to access NWM results programmatically. To demonstrate the utility of this cyberinfrastructure, we created additional web apps that illustrate how to use our REST API and communicate hydrologic forecasts with the aid of dynamic flood maps. This work offers a starting point for the development of a more comprehensive toolset to validate the NWM while also improving the ability to access and visualize NWM forecasts, and develop additional national‐scale‐derived products such as flood maps.  相似文献   
473.
474.
Environmental changes strongly impact the distribution of species and subsequently the composition of species assemblages. Although most community ecology studies represent temporal snap shots, long‐term observations are rather rare. However, only such time series allow the identification of species composition shifts over several decades or even centuries. We analyzed changes in the species composition of a southeastern German butterfly and burnet moth community over nearly 2 centuries (1840–2013). We classified all species observed over this period according to their ecological tolerance, thereby assessing their degree of habitat specialisation. This classification was based on traits of the butterfly and burnet moth species and on their larval host plants. We collected data on temperature and precipitation for our study area over the same period. The number of species declined substantially from 1840 (117 species) to 2013 (71 species). The proportion of habitat specialists decreased, and most of these are currently endangered. In contrast, the proportion of habitat generalists increased. Species with restricted dispersal behavior and species in need of areas poor in soil nutrients had severe losses. Furthermore, our data indicated a decrease in species composition similarity between different decades over time. These data on species composition changes and the general trends of modifications may reflect effects from climate change and atmospheric nitrogen loads, as indicated by the ecological characteristics of host plant species and local changes in habitat configuration with increasing fragmentation. Our observation of major declines over time of currently threatened and protected species shows the importance of efficient conservation strategies.  相似文献   
475.
476.
In recent years the concept of economic de-growth (decroissance) based on the literature of Nicolas Georgescu-Roegen e.g. [1], [2], [3] has found a revival in France, Italy, Spain and other countries, in the popular as well as in the academic literature. Therein authors took on board Georgescu-Roegens' categorical rejection of a steady-state economy (SSE), as proposed by Herman Daly [4]. They argue that economic de-growth is the only viable alternative goal to the growing economy. This position is challenged in this article and it is concluded that the two concepts are in fact complements. Economic de-growth is not a goal in itself, but the rich North's path towards a globally equitable SSE. Moreover the de-growth literature can benefit from the strong economic historic roots of the SSE and from Daly's macroeconomic concepts, while in return being able to give lessons about bottom-up approaches. This would be particularly important for the population issue, where Daly proposes limited birth licences. Unfortunately statements on demography are inconsistent and underdeveloped in the de-growth literature. Further it is concluded that most criticisms of the SSE are due to a too narrow and technocratic interpretation of the concept. Instead the SSE should be defined as a quasi steady-state, resting in a dynamic equilibrium and as an “unattainable goal”, which can and probably should be approximated.  相似文献   
477.
Zusammenfassung  Der Beitrag besch?ftigt sich mit der bald notwendigen Einführung einer Umweltvertr?glichkeitsprüfung für Pl?ne und Programme in das deutsche Umwelt-und Planungsrecht. Zun?chst werden Ziel und Zweck sowie europ?ischer Hintergrund dieses Umweltinstruments erl?utert. Sodann geht es um das Recht der Bauleitplanung. Es werden überlegungen angestellt, wie man den europ?ischen Anforderungen in diesem Bereich gerecht werden k?nnte. Siehe UWSF12 (6) 350 (2000) Schlagw?rter: deutsches Umwelt- und Planungsrecht; Pl?ne; Plan-UVP-Richtlinie; Programme; SEIA; Strategic Environmental Assessment (SEIA); Umweltvertraglichkeitsprüfung (UVP); UVP  相似文献   
478.
Abstract

Objective: Particular testing by functional decomposition of the automated driving function can potentially contribute to reducing the effort of validating highly automated driving functions. In this study, the required size of test suites for scenario-based testing and the potential to reduce it by functional decomposition are quantified for the first time.

Methods: The required size of test suites for scenario-based approval of a so-called Autobahn-Chauffeur (SAE Level 3) is analyzed for an exemplary set of scenarios. Based on studies of data from failure analyses in other domains, the possible range for the required test coverage is narrowed down and suitable discretization steps, as well as ranges for the influence parameters, are assumed. Based on those assumptions, the size of the test suites for testing the complete system is quantified. The effects that lead to a reduction in the parameter space for particular testing of the decomposed driving function are analyzed and the potential to reduce the validation effort is estimated by comparing the resulting test suite sizes for both methods.

Results: The combination of all effects leads to a reduction in the test suites’ size by a factor between 20 and 130, depending on the required test coverage. This means that the size of the required test suite can be reduced by 95–99% by particular testing compared to scenario-based testing of the complete system.

Conclusions: The reduction potential is a valuable contribution to overcome the parameter space explosion during the validation of highly automated driving. However, this study is based on assumptions and only a small set of exemplary scenarios. Thus, the findings have to be validated in further studies.  相似文献   
479.
Objective: The main objective of this article is to examine whether the Driving Anger Expression Inventory (DAX) applies to German drivers because this scale has previously been given to drivers in many different countries.

Methods: We applied German versions of the DAX, the Driving Anger Scale (DAS), and the State-Trait Anger Expression Inventory (STAXI) to a sample of 501 German drivers. We computed confirmatory factor analysis and principal axis factoring (PAF) analysis to examine the structure of driving anger expression in Germany. Finally, we related the drivers’ anger exp ression scores to their driving anger experiences and their general anger propensities to assess the validity of the DAX for German drivers.

Results: Results indicated that the DAX’s original factor structure does not apply to German drivers because the confirmatory factor analysis did not show a good model fit. An item analysis revealed that many DAX items had no meaningful variability. They were excluded from further analysis. The subsequent PAF analysis indicated that German drivers do not use personal physical aggression to express their driving anger. Instead, they reported unique preventive anger expression management behavior. In addition, their driving anger expressions were significantly related to their driving anger experiences and their general anger propensities indicated the validity of the refined DAX for German drivers.

Conclusions: We conclude that German drivers do not use strong behaviors to express their driving anger. Many statements of Deffenbacher et al.’s (Behav Res Ther. 40:717–737, 2002) original American questionnaire were not applicable for our sample of German drivers. These findings are in line with several other studies showing discrepancies in driving anger expression in various countries. Future investigations should examine the reasons for discrepancies in driving anger expression.  相似文献   

480.
The widespread usage of antibiotics in agriculture leads to releases into the environment, but there is insufficient knowledge of the side-effects on non-target organisms. Therefore, we investigated the effects of the sulfonamide-antibiotic sulfamethoxazole (SMX) on Caenorhabditis elegans at phenotypic, biochemical and molecular biological levels. Multiple endpoints, including life history traits, thermal stress resistance and lipid peroxidation, as well as gene expression profiles, were determined after exposure of the nematodes to SMX. In contrast to expectations, SMX prolonged the lifespan and increased both the body size and pharynx pumping rate. On the other hand, SMX delayed reproductive timing and caused lipid peroxidation. The total number of offspring and thermal stress resistance were unaffected. The up-regulation of hsp-16.1 indicated stress in general and the increased lipid peroxidation oxidative stress in particular. This oxidative stress indicated that mitohormesis was the likely cause of the longevity and that enhanced pumping frequency was probably the reason for the increased growth. The sole adverse effect was delayed initial reproduction. This delay, however, can be crucial for r-strategists, such as the bacterivorous model animal used, in sustaining their populations in the environment in the presence of predators. Bacterivorous animals, in turn, are essential to maintaining nutrient recycling via the microbial loop.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号