全文获取类型
收费全文 | 1572篇 |
免费 | 5篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 71篇 |
环保管理 | 80篇 |
综合类 | 522篇 |
基础理论 | 362篇 |
污染及防治 | 363篇 |
评价与监测 | 97篇 |
社会与环境 | 68篇 |
灾害及防治 | 10篇 |
出版年
2017年 | 14篇 |
2016年 | 20篇 |
2014年 | 21篇 |
2013年 | 69篇 |
2012年 | 22篇 |
2011年 | 45篇 |
2010年 | 44篇 |
2009年 | 48篇 |
2008年 | 66篇 |
2007年 | 51篇 |
2006年 | 46篇 |
2005年 | 45篇 |
2004年 | 41篇 |
2003年 | 37篇 |
2002年 | 48篇 |
2001年 | 59篇 |
2000年 | 54篇 |
1999年 | 34篇 |
1998年 | 20篇 |
1997年 | 30篇 |
1996年 | 28篇 |
1995年 | 30篇 |
1994年 | 28篇 |
1993年 | 26篇 |
1992年 | 19篇 |
1991年 | 36篇 |
1990年 | 50篇 |
1989年 | 23篇 |
1988年 | 27篇 |
1987年 | 20篇 |
1985年 | 21篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 30篇 |
1979年 | 18篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1976年 | 13篇 |
1974年 | 17篇 |
1972年 | 17篇 |
1971年 | 12篇 |
1969年 | 11篇 |
1968年 | 12篇 |
1967年 | 23篇 |
1966年 | 19篇 |
1965年 | 13篇 |
1964年 | 12篇 |
1962年 | 13篇 |
1958年 | 14篇 |
1957年 | 12篇 |
排序方式: 共有1583条查询结果,搜索用时 734 毫秒
161.
U. Pinto 《中国人口.资源与环境(英文版)》2015,13(3):250-264
The demand for potable water is rising rapidly due to an ever-increasing population, economic activities, and dwindling water supplies. To provide adequate water supplies in the future, understanding the issues and challenges in the reuse of water and developing appropriate strategies for reuse will be critical. One way to augment water supplies for residential use is to reuse graywater – the wastewater from kitchens, bathrooms, and laundries. In this article, we critically review the evolution of water reuse, the definition of graywater, graywater reuse practices, volumes and flow in different situations, and graywater characteristics. We then examine the issues associated with different graywater treatment methods and how using graywater for irrigation around homes affects soil quality and plant growth. The study concludes that graywater treatment costs, human health risks, and its effect on soil quality are some of the challenges that need to be addressed in the future for widespread and sustainable reuse of graywater for irrigation around homes. 相似文献
162.
Sullivan TJ Moore JA Thomas DR Mallery E Snyder KU Wustenberg M Wustenberg J Mackey SD Moore DL 《Environmental management》2007,40(6):958-965
An experimental study was conducted in Tillamook, Oregon, USA, to quantify the effectiveness of edge-of-field vegetated buffers
for reducing transport of fecal coliform bacteria (FCB) from agricultural fields amended with dairy cow manure. Installation
of vegetated buffers on loamy soils dramatically reduced the bacterial contamination of runoff water from manure-treated pasturelands,
but the size of the vegetated buffer was not an important determinant of bacterial removal efficiency. Only 10% of the runoff
samples collected from treatment cells having vegetated buffers exhibited FCB concentrations >200 colony forming units (cfu)/100
mL (a common water quality standard value), and the median concentration for all cells containing vegetated buffers was only
6 cfu/100 mL. The presence of a vegetated buffer of any size, from 1 to 25 m, generally reduced the median FCB concentration
in runoff by more than 99%. Results for FCB load calculations were similar. Our results suggest that where substantial FCB
contamination of runoff occurs from manure-treated pasturelands, it might be disproportionately associated with specific field
or management conditions, such as the presence of soils that exhibit low water infiltration and generate larger volumes of
runoff or the absence of a vegetated buffer. Buffer size regulations that do not consider such differences might not be efficient
or effective in reducing bacterial contamination of runoff. 相似文献
163.
164.
Dilek Topcu Horst Behrendt U. Brockmann U. Claussen 《Environmental monitoring and assessment》2011,174(1-4):361-388
Natural background concentrations of nutrients are needed for the assessments of eutrophication processes and their status. Natural background concentrations of total nitrogen (TN) and total phosphorus (TP) were modelled for the rivers discharging into the German Bight and the Rhine considering individual catchment sizes, freshwater flows and soil types. These data were validated by comparison with data from unpolluted rivers. The consistency of modelled and some compiled nutrient concentrations was confirmed by their area-specific load dependency on freshwater discharges. Pristine inorganic nutrient concentrations were deduced from modelled relations to TN and TP in unpolluted rivers. Pristine nutrient gradients between rivers and offshore waters were estimated by linear mixing until a salinity of 32, continued by hyperbolic fits towards recent mean offshore values (salinity 34.5?C35). Based on these gradients and recent mean salinities, maps of pristine surface gradients were plotted for the whole German Bight. Variability was transferred from recent conditions as percentage of standard deviation. Reported historical nutrient data and concentrations from unpolluted rivers, coastal and offshore North Sea waters are discussed concerning their relations to natural background conditions. 相似文献
165.
The Channel of Santa Cruz is a mangrove area in northeastern Brasil 40 km north of Recife. Until 1991 a chlor-alkali factory
discharged large amounts of mercury into the main tributary of the channel, the Rio Botafogo. The objective of this study
was to assess the potential of the mangrove oyster Crassostrea rhizophorae as a bioindicator for mercury in this area and to examine the influence of condition on mercury concentrations in the oysters.
The investigation was carried out in the late rainy season (July to September) 1993, in the rainy season (April to June) 1994
and in the dry season (November/December) 1994. At 11 stations in the channel, mangrove oysters, surface sediments and suspended
matter were sampled, representing different compartments of the system. The distribution of mercury in the Channel of Santa
Cruz exhibited for all compartments the same distinct spatial pattern with maxima in the Rio Botafogo. Seasonal variations
were small and revealed no clear tendencies. In addition, mangrove oysters were transplanted from more contaminated stations
to less contaminated stations and vice versa. These experiments were designed to study the oysters' capability to adjust their
mercury concentrations to a changing bioavailability of mercury. The transplantation experiments suggest that the oysters
are capable to adjust to changing ambient mercury availability within a few months. The transplantation experiments also revealed
the importance of condition changes on the mercury concentration of the oysters. This factor should not be ignored during
pollution studies. However, condition had apparently no strong influence on the spatial or seasonal mercury variations of
the oysters. The mangrove oyster is a suitable bioindicator for long-term changes in mercury availability.
Received: 20 August 1997 / Accepted: 15 January 1998 相似文献
166.
Summary Extensive field and laboratory studies show that Damaraland mole-rats, like naked mole-rats, have an extreme form of vertebrate sociality. Colonies usually contain 2 reproductives and up to 39 non-breeding siblings, 90% of whom live a socially-induced lifetime of sterility; they remain in the natal colony, forage for food, defend the colony and care for successive litters. Although there is heightened dispersal following good rainfall, the majority of adult non-reproductives remain in their natal colony and failure to disperse is not directly attributable to habitat saturation or unfavourable soil conditions. A major dispersal event follows the death of a reproductive. Differences in colony cohesion, ethology and the hormonal profiles of non-reproductive animals suggests that eusociality evolved along different pathways in these two phylogenetically divergent genera of the Bathyergidae. 相似文献
167.
R. Wassmann H.U. Neue J.K. Ladha M.S. Aulakh 《Environment, Development and Sustainability》2004,6(1-2):65-90
The rice-wheat belt comprises nearly 24–27 million ha in South and East Asia. Rice is generally grown in flooded fields whereas the ensuing wheat crop requires well-drained soil conditions. Consequently, both crops differ markedly in nature and intensity of greenhouse gas (GHG) fluxes, namely emission of (1) methane (CH4) and (2) nitrous oxide (N2O) as well as the sequestration of (3) carbon dioxide. Wetland rice emits large quantities of CH4; strategies to CH4 emissions include proper management of organic inputs, temporary (mid-season) field drainage and direct seeding. As for the wheat crop, the major GHG is N2O that is emitted in short-term pulses after fertilization, heavy rainfall and irrigation events. However, N2O is also emitted in larger quantities during fallow periods and during the rice crop as long as episodic irrigation or rainfall result in aerobic-anaerobic cycles. Wetland rice ensures a relatively high content of soil organic matter in the rice-wheat system as compared to permanent upland conditions. In terms of global warming potential, baseline emissions of the rice-wheat system primarily depend on the management practices during the rice crop while emissions from the wheat crop remain less sensitive to different management practices. The antagonism between CH4 and N2O emissions is a major impediment for devising effective mitigation strategies in rice-wheat system - measures to reduce the emission of one GHG often intensify the emission of the other GHG. 相似文献
168.
Vertical migration ofGonyaulax catenata andMesodinium rubrum 总被引:1,自引:0,他引:1
U. Passow 《Marine Biology》1991,110(3):455-463
Diel migration patterns ofGonyaulax catenata andMesodinium rubrum in the central Baltic during spring 1986 are presented. The depth at which maximum cell concentration of these species occurred was dependent during daytime to a great degree on light intensity; it is hypothesized that the organisms migrated upwards toward higher light intensities until a certain threshold irradiance was reached, after which migration was directed downwards to avoid light intensities higher than the threshold. This threshold level probably depended on nutrient conditions and on the daily average of total irradiance of the foregoing days (light history). Furthermore, it is hypothesized that migration is an important mechanism for adapting to daily irradiance fluctuations. The dependence of migration on irradiance was more obvious forG. catenata than forM. rubrum. 相似文献
169.
170.
Ivemark syndrome with agenesis of the corpus callosum: a case report with a review of the literature
Asplenia associated with situs ambiguus, symmetric liver, bilateral trilobulated lungs, and a complex heart defect was diagnosed on autopsy in a 14-day-old infant. Furthermore, examination of the brain displayed agenesis of the corpus callosum (ACC) with pachygyria and hydrocephalus. The characteristic association of asplenia with visceroatrial heterotaxia is traditionally named after the Swedish pediatrician, Ivemark. Although exceptional, association of Ivemark syndrome with callosal agenesis has been reported recently. The concept of ‘developmental fields’ describes morphogenetically reactive units of the embryo determining and controlling the development of complex structures in a hierarchical manner. Lateralization defects such as situs inversus, asplenia or polysplenia due to defective left–right axis development, as well as decussation defects such as ACC, are considered as defects of the primary developmental field. Therefore, additional callosal agenesis in Ivemark syndrome may be a coherent and synchronic defect in the primary developmental field rather than a causally independent malformation. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献