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   582篇
  免费   18篇
  国内免费   6篇
安全科学   28篇
废物处理   28篇
环保管理   125篇
综合类   42篇
基础理论   147篇
污染及防治   158篇
评价与监测   32篇
社会与环境   18篇
灾害及防治   28篇
  2022年   9篇
  2021年   13篇
  2020年   13篇
  2019年   12篇
  2018年   19篇
  2017年   16篇
  2016年   22篇
  2015年   19篇
  2014年   17篇
  2013年   48篇
  2012年   22篇
  2011年   33篇
  2010年   26篇
  2009年   20篇
  2008年   21篇
  2007年   28篇
  2006年   26篇
  2005年   18篇
  2004年   16篇
  2003年   16篇
  2002年   31篇
  2001年   4篇
  2000年   8篇
  1999年   7篇
  1998年   11篇
  1997年   7篇
  1996年   8篇
  1995年   3篇
  1994年   7篇
  1993年   9篇
  1992年   3篇
  1991年   5篇
  1990年   3篇
  1989年   6篇
  1988年   3篇
  1986年   4篇
  1985年   6篇
  1984年   4篇
  1983年   3篇
  1982年   10篇
  1981年   7篇
  1980年   6篇
  1979年   8篇
  1978年   5篇
  1977年   7篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1971年   3篇
排序方式: 共有606条查询结果,搜索用时 234 毫秒
221.
We explored the utility of incorporating easily measured, biologically realistic movement rules into simple models of dispersal. We depart from traditional random walk models by designing an individual-based simulation model where we decompose animal movement into three separate processes: emigration, between-patch movement, and immigration behaviour. These processes were quantified using experiments on the omnivorous insect Dicyphus hesperus moving through a tomato greenhouse. We compare the predictions of the individual-based model, along with a series of biased random walk models, against an independent experimental release of D. hesperus. We find that in this system, the short-term dispersal of these insects is described well by our individual-based model, but can also be described by a 2D grid-based biased random walk model when mortality is accounted for.  相似文献   
222.
The ontogeny of diving and foraging behavior of northern fur seal pups from a stable population on Bering Island, Russia, was recorded with animal-borne instruments during their first few months at sea, a critical period during their first year at sea. Thirty-five pups were instrumented with satellite-linked time-depth recorders and stomach temperature pills. Diving occurred predominantly at night with deeper and longer dives as the pups matured. Mean dive depths were correlated with lunar illumination, whereas mean dive durations were also correlated with time of day and sex. Foraging success did not differ between sexes, and there was no relationship between meal size (as indicated by feeding event duration and minimum stomach temperature) and lunar illumination fraction or maximum foraging depth. Although most pups were able to successfully forage within 3 days of starting their migration, the number of feeding events recorded each day remained low (mean 1.6 events day?1). There was no indication of an appreciable increase in meal size after the first 2 weeks of the migration despite an increase in dive frequency and depth. The results are consistent with observations that pups do not gain mass during their first year and emphasize the risk of starvation from infrequent foraging in cold water.  相似文献   
223.
Codium fragile ssp. tomentosoides is one of the five most invasive macroalgae worldwide. We compared epiphytic assemblages between native (ssp. tasmanicum and ssp. novae-zelandiae combined) and non-indigenous (ssp. tomentosoides) subspecies of Codium fragile on three rocky intertidal shores in southeast Australia. Twelve species of epiphytes covered up to 20% of the surface of both native and non-indigenous Codium subspecies, but none were unique to either subspecies. For C. fragile subspecies, epiphytic cover declined from the lower (older) parts of the thallus to the branch tips. The abundance and species composition of epiphytes differed significantly between native and non-indigenous C. fragile, but differences varied among rocky shores. Results demonstrate that non-indigenous C. fragile does not play a functionally similar role to closely related native Codium subspecies. Spatial differences in epiphytic assemblages between Codium subspecies among rocky shores demonstrate that effects of non-indigenous species may be strongly location specific. Thus, our study emphasises the need to investigate variation in the effects of invaders across the regional landscape.  相似文献   
224.
Climate change driven ocean acidification and hypercapnia may have a negative impact on fertilization in marine organisms because of the narcotic effect these stressors exert on sperm. In contrast, warmer, less viscous water may have a positive influence on sperm swimming speed and so ocean warming may enhance fertilization. To address questions on future vulnerabilities we examined the interactive effects of near-future ocean warming and ocean acidification/hypercapnia on fertilization in intertidal and shallow subtidal echinoids (Heliocidaris erythrogramma, H. tuberculata, Tripneustes gratilla, Centrostephanus rodgersii), an asteroid (Patiriella regularis) and an abalone (Haliotis coccoradiata). Batches of eggs from multiple females were fertilized by sperm from multiple males in all combinations of three temperature and three \textpH/P\textCO2 {\text{pH}}/P_{{{\text{CO}}_{2} }} treatments. Experiments were placed in the setting of projected near-future conditions for southeast Australia, an ocean change hot spot. There was no significant effect of warming and acidification on the percentage of fertilization. These results indicate that fertilization in these species is robust to temperature and \textpH/P\textCO2 {\text{pH}}/P_{{{\text{CO}}_{2} }} fluctuation. This may reflect adaptation to the marked fluctuation in temperature and pH that characterises their shallow water coastal habitats. Efforts to identify potential impacts of ocean change to the life histories of coastal marine invertebrates are best to focus on more vulnerable embryonic and larval stages because of their long time in the water column where seawater chemistry and temperature have a major impact on development.  相似文献   
225.
Duffy MA  Cáceres CE  Hall SR  Tessier AJ  Ives AR 《Ecology》2010,91(11):3322-3331
In nature, multiple parasite species infect multiple host species and are influenced by processes operating across different spatial and temporal scales. Data sets incorporating these complexities offer exciting opportunities to examine factors that shape epidemics. We present a method using generalized linear mixed models in a multilevel modeling framework to analyze patterns of variances and correlations in binomially distributed prevalence data. We then apply it to a multi-lake, multiyear data set involving two Daphnia host species and nine microparasite species. We found that the largest source of variation in parasite prevalence was the species identities of host-parasite pairs, indicating strong host-parasite specificity. Within host-parasite combinations, spatial variation (among lakes) exceeded interannual variation. This suggests that factors promoting differences among lakes (e.g., habitat characteristics and species interactions) better explain variation in peak infection prevalence in our data set than factors driving differences among years (e.g., climate). Prevalences of parasites in D. dentifera were more positively correlated than those for D. pulicaria, suggesting that similar factors influenced epidemic size among parasites in D. dentifera. Overall, this study demonstrates a method for parsing patterns of variation and covariation in infection prevalence data, providing greater insight into the relative importance of different underlying drivers of parasitism.  相似文献   
226.
有效、可靠的数据和信息是环境管理的基础和主线,是政府部门确定环境管理目标、衡量进展以及同所有利益相关方共享信息的基础。美国环保局(EPA)从整体视角和跨学科观点提出环境信息生命周期模型,能够更好地理解环境信息的生产者、管理者、提供者和使用者等不同角色的作用。本文介绍了环境信息生命周期模型的各环节和要素,包括政策、规划和项目,数据采集和管理,信息交换和共享,信息管理,发现、获取信息,理解、使用信息,用户/公众反馈等,用于评估环境管理业务的数据和信息需求,帮助提高数据质量,增强公众获取环境信息的能力。环保部门需要关注数据质量的不确定性以及不同部门之间缺乏信息共享的问题,将环境信息生命周期的方法融入中国的环境管理和信息化建设,将提高环境数据的质量和政府透明度。本文针对中国的环保信息化建设提出了若干政策建议。  相似文献   
227.
Uses of science by environmental justice (EJ) activists reflect struggles to challenge professional scientific expertise, achieve fair outcomes, and effectively participate in decision-making processes. This qualitative research analyses the relationship between citizen science and EJ in a new waste facility siting conflict in urban Los Angeles, namely connections between citizen science and four dimensions of EJ: fair distribution, respect and recognition, participation in decision-making, and community capabilities. Citizen science is one tactic in EJ, yet little research investigates its role in a new facility siting conflict, particularly in relation to multi-faceted EJ goals. The research reveals opportunities for individual empowerment and community capacity building using citizen science, and a small measure of improved respect and recognition for participants who brought their own knowledge, research, and voices to the table. At the same time, the work identifies limitations on citizen science to improve local participatory procedures and decision-making, which also constricted the achievement of outcomes most desired by the EJ group: to prevent approval and construction of the new waste facility. This paper argues that uses of citizen science contributed to partial achievement of EJ goals, while hindered by governance processes that call for public participation yet shield decision-makers from substantive engagement with the volume or content of that participation.  相似文献   
228.
Urban green/blue spaces are put under pressure as urban areas grow, develop and evolve. It is increasingly recognized, however, that green/blue spaces provide important ecosystem services, stimulate higher real estate prices and prevent flooding problems. This paper aims to assess and compare the socio-economic impacts of potential green/blue space, urban residential and road infrastructure development scenarios in the Lyon Confluence project area (France), using the Sustainable Urbanizing Landscape Development (SULD) hedonic pricing simulation model. Results show four major tendencies regarding the value-added of green/blue spaces in urban landscapes: (1) cities become more compact; (2) population densities increase; (3) real estate values rise; and (4) demographic distribution patterns change. The magnitude of these impacts depends, however, on the quality and size of the intervention, the social classes attracted to the intervention area and on the location of the intervention relative to existing residential areas, urban centres, road infrastructure and environmental amenities.  相似文献   
229.
Key attributes of the source zone and the expanding dissolved plume at a trichloroethene (TCE) site in Australia were evaluated using trends in groundwater monitoring data along with data from on-line volatile organic compound (VOC) samplers and passive flux meters (PFMs) deployed in selected wells. These data indicate that: (1) residual TCE source mass in the saturated zone, estimated using two innovative techniques, is small ( 10 kg), which is also reflected in small source mass discharge ( 3 g/day); (2) the plume is disconnecting, based on TCE concentration contours and TCE fluxes in wells along a longitudinal transect; (3) there is minimal biodegradation, based on TCE mass discharge of  6 g/day at a plume control plane  175 m from source, which is also consistent with aerobic geochemical conditions observed in the plume; and (4) residual TCE in the vadose zone provides episodic inputs of TCE mass to the plume during infiltration/recharge events. TCE flux data also suggest that the small residual TCE source mass is present in the low-permeability zones, thus making source treatment difficult. Our analysis, based on a synthesis of the archived data and new data, suggests that source treatment is unwarranted, and that containment of the large TCE plume ( 1.2 km long,  0.3 km wide; 17 m deep;  2000–2500 kg TCE mass) or institutional controls, along with a long-term flux monitoring program, might be necessary. The flux-based site management approach outlined in this paper provides a novel way of looking beyond the complexities of groundwater contamination in heterogeneous domains, to make intelligent and informed site decisions based on strategic measurement of the appropriate metrics.  相似文献   
230.
Macrocapsules, composed of a pH-sensitive polymer and phosphate buffer, offer a novel remediation alternative for acidic ground waters. To test their potential effectiveness, laboratory experiments were carried out followed by a field trial within a coal pile runoff (CPR) acidic contaminant plume. Results of traditional limestone and macrocapsule treatments were compared in both laboratory and field experiments. Macrocapsules were more effective than limestone as a passive treatment for raising pH in well water from 2.5 to 6 in both laboratory and field experiments. The limestone treatments had limited impact on pH, only increasing pH as high as 3.3, and armoring by iron was evident in the field trial. Aluminum, iron and sulfate concentrations remained relatively constant throughout the experiments, but phosphate increased (0.15-32 mg/L), indicating macrocapsule release. This research confirmed that macrocapsules may be an effective alternative to limestone to treat highly acidic ground water.  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