全文获取类型
收费全文 | 6420篇 |
免费 | 112篇 |
国内免费 | 94篇 |
专业分类
安全科学 | 259篇 |
废物处理 | 295篇 |
环保管理 | 1498篇 |
综合类 | 777篇 |
基础理论 | 1403篇 |
环境理论 | 6篇 |
污染及防治 | 1633篇 |
评价与监测 | 420篇 |
社会与环境 | 273篇 |
灾害及防治 | 62篇 |
出版年
2023年 | 42篇 |
2022年 | 36篇 |
2021年 | 75篇 |
2020年 | 48篇 |
2019年 | 84篇 |
2018年 | 113篇 |
2017年 | 131篇 |
2016年 | 168篇 |
2015年 | 176篇 |
2014年 | 177篇 |
2013年 | 618篇 |
2012年 | 251篇 |
2011年 | 351篇 |
2010年 | 284篇 |
2009年 | 283篇 |
2008年 | 341篇 |
2007年 | 355篇 |
2006年 | 310篇 |
2005年 | 208篇 |
2004年 | 258篇 |
2003年 | 230篇 |
2002年 | 227篇 |
2001年 | 145篇 |
2000年 | 135篇 |
1999年 | 113篇 |
1998年 | 90篇 |
1997年 | 91篇 |
1996年 | 91篇 |
1995年 | 102篇 |
1994年 | 81篇 |
1993年 | 71篇 |
1992年 | 87篇 |
1991年 | 67篇 |
1990年 | 62篇 |
1989年 | 60篇 |
1988年 | 39篇 |
1987年 | 42篇 |
1986年 | 46篇 |
1985年 | 45篇 |
1984年 | 49篇 |
1983年 | 52篇 |
1982年 | 48篇 |
1981年 | 64篇 |
1980年 | 47篇 |
1979年 | 31篇 |
1978年 | 27篇 |
1977年 | 19篇 |
1975年 | 17篇 |
1971年 | 15篇 |
1970年 | 16篇 |
排序方式: 共有6626条查询结果,搜索用时 15 毫秒
161.
Phytoremediation, the use of plants for in situ contaminant cleanup, is gaining new appreciation as an aesthetically pleasing, sustainable method that naturally makes use of solar power. Hybrid poplars are widely used because they grow rapidly and have high transpiration rates, making them advantageous for hydraulic control of groundwater. However, the tendency for trees and other vegetation to uptake metals may be a disadvantage in some settings due to potential redistribution of metals from groundwater to the ground surface. Therefore, a pilot test in the upper midwestern United States was implemented to evaluate the applicability of poplars to groundwater withdrawal and metals transport. © 2009 Wiley Periodicals, Inc. 相似文献
162.
163.
Liz Root Erwin van der Krabben Tejo Spit 《Journal of Environmental Planning and Management》2015,58(4):701-718
Based on a case study of the Stadshaven port redevelopment in Rotterdam, this paper explores whether existing spatial planning mechanisms and processes can be used to facilitate local-level investment in climate-resilient public infrastructure and/or whether new processes and mechanisms are required to encourage investment in climate adaptation. The study reveals several key findings. First, a lack of conventional funding sources or formalised regulatory framework allowed room for experimentation with existing mechanisms and flexible strategies. Second, project planners are currently ambivalent towards introducing new mechanisms as a means to overcome implementation challenges. The case provides evidence about the role of the governance process, not simply as a means of system coordination that exists in isolation from institutional norms and values, but rather as a space for innovation, which can contribute towards reducing the financial gap associated with climate adaptation. 相似文献
164.
Doug P. Armstrong Elizabeth H. Parlato Barbara Egli Wendy J. Dimond Renske Kwikkel Åsa Berggren Mhairi McCready Kevin A. Parker John G. Ewen 《Conservation biology》2021,35(3):859-869
Inbreeding depression is an important long-term threat to reintroduced populations. However, the strength of inbreeding depression is difficult to estimate in wild populations because pedigree data are inevitably incomplete and because good data are needed on survival and reproduction. Predicting future population consequences is especially difficult because this also requires projecting future inbreeding levels and their impacts on long-term population dynamics, which are subject to many uncertainties. We illustrate how such projections can be derived through Bayesian state-space modeling methods based on a 26-year data set for North Island Robins (Petroica longipes) reintroduced to Tiritiri Matangi Island in 1992. We used pedigree data to model increases in the average inbreeding level (F ) over time based on kinship of possible breeding pairs and to estimate empirically Ne/N (effective/census population size). We used multiple imputation to model the unknown components of inbreeding coefficients, which allowed us to estimate effects of inbreeding on survival for all 1458 birds in the data set while modeling density dependence and environmental stochasticity. This modeling indicated that inbreeding reduced juvenile survival (1.83 lethal equivalents [SE 0.81]) and may have reduced subsequent adult survival (0.44 lethal equivalents [0.81]) but had no apparent effect on numbers of fledglings produced. Average inbreeding level increased to 0.10 (SE 0.001) as the population grew from 33 (0.3) to 160 (6) individuals over the 25 years, giving a ratio of 0.56 (0.01). Based on a model that also incorporated habitat regeneration, the population was projected to reach a maximum of 331–1144 birds (median 726) in 2130, then to begin a slow decline. Without inbreeding, the population would be expected stabilize at 887–1465 birds (median 1131). Such analysis, therefore, makes it possible to empirically derive the information needed for rational decisions about inbreeding management while accounting for multiple sources of uncertainty. 相似文献
165.
Development of soil chemical and biological properties in the initial stages of post-mining deposition sites 总被引:2,自引:0,他引:2
Nikolaos Monokrousos George Boutsis John D. Diamantopoulos 《Environmental monitoring and assessment》2014,186(12):9065-9074
The aim of this study was to assess the seasonal development of the physicochemical (pH, organic C, organic N, extractable P, Ca2+, Mg2+) and biological soil properties (microbial biomass, activities of urease, dehydrogenase and alkaline phosphatase) of the topsoil of mine deposition sites that differed based on the material used exclusively for their creation: (a) marlstones, (b) red-grey formations (RGF), and (c) fly ash (FA), during the first year after their creation. Our hypothesis was that all deposition sites, regardless the material they consist of, present equal opportunities for the establishment of spontaneous vegetation. All macronutrients concentrations (P, Ca2+, and Mg2+) remained constant with time and were found to be higher in the FA sites. Organic C, organic N, all enzyme activities, and microbial biomass were higher in the RGF and marl depositions, with marl sites presenting the highest values. All values of biological variables, with the exception of alkaline phosphatase, increased with time. The alkaline environment along with the slow improvement in soil biological properties of the FA sites seemed to present the most unfavorable conditions for spontaneous vegetation growth. On the contrary, the other two spoil materials presented significant improvement in the initial stages of soil formation in terms of soil functionality. 相似文献
166.
John Kelly 《Journal of Land Use Science》2020,15(2-3):203-220
ABSTRACT Sketch-map-facilitated interviews were conducted in 23 villages in two adjacent regions in the southern Yucatan Peninsula of Mexico – the Maya (and increasingly Mennonite) forest-agriculture mosaic of the Chenes, and the late-20th-century-settlement forest frontier of Calakmul – to determine the frequency and typology of local-scale reserves, including the external (e.g. Payments for Environmental Services programs) and internal sources of their generation. 9% of the study communities are found to satisfy the author’s criteria for deliberate, autochthonous reserves. The static polygon reserve and static map are found to have limited value for understanding the evolving cultural ecologies of these regions. Alternative approaches are discussed, particularly those employed by geographers. 相似文献
167.
van Heezik Yolanda Freeman Claire Davidson Katherine Lewis Blake 《Environmental management》2020,66(1):42-55
Environmental Management - Activities undertaken by householders in their gardens have huge potential to enhance city-wide biodiversity, but programs aimed at activating householders require an... 相似文献
168.
Rosaleen Duffy Freya A. V. St John Bram Büscher Dan Brockington 《Conservation biology》2016,30(1):14-22
Conservation organizations have increasingly raised concerns about escalating rates of illegal hunting and trade in wildlife. Previous studies have concluded that people hunt illegally because they are financially poor or lack alternative livelihood strategies. However, there has been little attempt to develop a richer understanding of the motivations behind contemporary illegal wildlife hunting. As a first step, we reviewed the academic and policy literatures on poaching and illegal wildlife use and considered the meanings of poverty and the relative importance of structure and individual agency. We placed motivations for illegal wildlife hunting within the context of the complex history of how wildlife laws were initially designed and enforced to indicate how hunting practices by specific communities were criminalized. We also considered the nature of poverty and the reasons for economic deprivation in particular communities to indicate how particular understandings of poverty as material deprivation ultimately shape approaches to illegal wildlife hunting. We found there is a need for a much better understanding of what poverty is and what motivates people to hunt illegally. 相似文献
169.
170.
The recent intensification of human disturbances in the Caribbean has increased the prevalence of partial mortality on coral colonies. Partial mortality can change colony size by directly shrinking colonies or by splitting colonies into fragments. A reduction in colony size can also adversely affect fecundity and fitness as internal resources shift away from reproduction toward colony maintenance. This study aimed to determine whether three Caribbean coral species, Siderastrea siderea, Montastraea faveolata, and Diploria strigosa, along the reef tract in Puerto Morelos, Mexico (20o52′N, 86o51′W), continued to dedicate resources to reproduction when colonies were fragmented to pre-maturation size. Contrary to expectations, eggs were found in colonies that were smaller than the maturation size and had been subjected to partial mortality. The continued dedication of resources toward reproduction, even in the smallest colonies, suggests that resource trade-offs away from reproduction are not as rigid as previously suggested in stressed corals. 相似文献