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931.
932.
The removal of As(III) and As(V) from aqueous solution was investigated using waste cast iron, which is a byproduct of the iron casting process in foundries. Two types of waste cast iron were used in the experiment: grind precipitate dust (GPD) and cast iron shot (CIS). The X-ray diffraction analysis indicated the presence of Fe0 on GPD and CIS. Batch experiments were performed under different concentrations of As(III) and As(V) and at various initial pH levels. Results showed that waste cast iron was effective in the removal of arsenic. The adsorption isotherm study indicated that the Langmuir isotherm was better than the Freundlich isotherm at describing the experimental result. In the adsorption of both As(III) and As(V), the adsorption capacity of GPD was greater than CIS, mainly due to the fact that GPD had higher surface area and weight percent of Fe than CIS. Results also indicated the removal of As(III) and As(V) by GPD and CIS was influenced by the initial solution pH, generally decreasing with increasing pH from 3.0 to 10.5. In addition, both GPD and CIS were more effective at the removal of As(III) than As(V) under given experimental conditions. This study demonstrates that waste cast iron has potential as a reactive material to treat wastewater and groundwater containing arsenic. 相似文献
933.
An agenda for assessing and improving conservation impacts of sustainability standards in tropical agriculture 下载免费PDF全文
Jeffrey C. Milder Margaret Arbuthnot Allen Blackman Sharon E. Brooks Daniele Giovannucci Lee Gross Elizabeth T. Kennedy Kristin Komives Eric F. Lambin Audrey Lee Daniel Meyer Peter Newton Ben Phalan Götz Schroth Bambi Semroc Henk Van Rikxoort Michal Zrust 《Conservation biology》2015,29(2):309-320
Sustainability standards and certification serve to differentiate and provide market recognition to goods produced in accordance with social and environmental good practices, typically including practices to protect biodiversity. Such standards have seen rapid growth, including in tropical agricultural commodities such as cocoa, coffee, palm oil, soybeans, and tea. Given the role of sustainability standards in influencing land use in hotspots of biodiversity, deforestation, and agricultural intensification, much could be gained from efforts to evaluate and increase the conservation payoff of these schemes. To this end, we devised a systematic approach for monitoring and evaluating the conservation impacts of agricultural sustainability standards and for using the resulting evidence to improve the effectiveness of such standards over time. The approach is oriented around a set of hypotheses and corresponding research questions about how sustainability standards are predicted to deliver conservation benefits. These questions are addressed through data from multiple sources, including basic common information from certification audits; field monitoring of environmental outcomes at a sample of certified sites; and rigorous impact assessment research based on experimental or quasi‐experimental methods. Integration of these sources can generate time‐series data that are comparable across sites and regions and provide detailed portraits of the effects of sustainability standards. To implement this approach, we propose new collaborations between the conservation research community and the sustainability standards community to develop common indicators and monitoring protocols, foster data sharing and synthesis, and link research and practice more effectively. As the role of sustainability standards in tropical land‐use governance continues to evolve, robust evidence on the factors contributing to effectiveness can help to ensure that such standards are designed and implemented to maximize benefits for biodiversity conservation. 相似文献
934.
Linking irreplaceable landforms in a self‐organizing landscape to sensitivity of population vital rates for an ecological specialist 下载免费PDF全文
Wade A. Ryberg Michael T. Hill Charles W. Painter Lee A. Fitzgerald 《Conservation biology》2015,29(3):888-898
Irreplaceable, self‐organizing landforms and the endemic and ecologically specialized biodiversity they support are threatened globally by anthropogenic disturbances. Although the outcome of disrupting landforms is somewhat understood, little information exists that documents population consequences of landform disturbance on endemic biodiversity. Conservation strategies for species dependent upon landforms have been difficult to devise because they require understanding complex feedbacks that create and maintain landforms and the consequences of landform configuration on demography of species. We characterized and quantified links between landform configuration and demography of an ecological specialist, the dunes sagebrush lizard (Sceloporus arenicolus), which occurs only in blowouts (i.e., wind‐blown sandy depressions) of Shinnery oak (Quercus havardii) sand‐dune landforms. We used matrix models to estimate vital rates from a multisite mark‐recapture study of 6 populations occupying landforms with different spatial configurations. Sensitivity and elasticity analyses demonstrated demographic rates among populations varied in sensitivity to different landform configurations. Specifically, significant relationships between blowout shape complexity and vital rate elasticities suggested direct links between S. arenicolus demography and amount of edge in Shinnery oak sand‐dune landforms. These landforms are irreplaceable, based on permanent transition of disturbed areas to alternative grassland ecosystem states. Additionally, complex feedbacks between wind, sand, and Shinnery oak maintain this landform, indicating restoration through land management practices is unlikely. Our findings that S. arenicolus population dynamics depended on landform configuration suggest that failure to consider processes of landform organization and their effects on species’ population dynamics may lead to incorrect inferences about threats to endemic species and ineffective habitat management for threatened or endangered species. As such, successful conservation of these systems and the biodiversity they support must be informed by research linking process‐oriented studies of self‐organized landforms with studies of movement, behavior, and demography of species that dwell in them. 相似文献
935.
936.
Lynch Amanda H. Griggs David Joachim Lee Salminen Ed Heider Chris Kestin Tahl Zhu Xuan Veland Siri 《Regional Environmental Change》2017,17(3):767-776
Regional Environmental Change - Geographic information systems are a means to develop a common framework for the integration of a range of perspectives into natural resources management decisions.... 相似文献
937.
938.
939.
Sang Don Lee M. Worth Calfee Leroy Mickelsen Matt Clayton Abderrahmane Touati 《补救:环境净化治理成本、技术与工艺杂志》2014,24(2):123-133
The cleaning robots, a vacuum‐based robot (R2) and a wetted‐wipe‐based robot (R4), were evaluated in this study to determine their effectiveness for sampling Bacillus atrophaeus spores. The tests were designed to evaluate the benefit of robot sampling on large areas with two different contamination scenarios: a high‐concentration, low spatial extent contamination (hot spot) and a low concentration, high spatial extent contamination (widely dispersed). The hot spot tests were conducted with the high spore contamination (approximately 107 colony forming units [CFUs]) on a limited area (30.5 cm × 30.5 cm), 2 percent of the entire test. The widely dispersed tests were conducted with approximately 0.1 CFUs/cm2 for floor laminate and approximately 10 CFUs/cm2 for carpet surfaces. The widely dispersed tests distributed spores across the test surface and covered approximately 40 percent of the entire test area. The test results showed that both robots successfully sampled a large quantity of spores from carpet and floor laminate surfaces for both test scenarios. Robot performance is discussed in the context of currently used surface sampling methods. © 2014 Wiley Periodicals, Inc.* 相似文献
940.
Plants growing in waterlogged environments are subjected to low oxygen levels around submerged tissues. While internal oxygen
transport has been postulated as an important factor governing flooding tolerance, respiration rates and abilities to take
up oxygen under hypoxic conditions have been largely ignored in plant studies. In this study, physiological characteristics
related to internal oxygen transport, respiration, and oxygen affinity were studied in low intertidal marsh species (Spartina alterniflora and S. anglica) and middle to high intertidal species (S. densiflora, S. patens, S. foliosa, a S. alterniflora × S. foliosa hybrid, S. spartinae, and Distichlis spicata). These marsh plants were compared to the inland species S. pectinata and the crop species rice (Oryza sativa), corn (Zea mays), and oat (Avena sativa). Plants were grown in a greenhouse under simulated estuarine conditions. The low marsh species S. anglica was found to transport oxygen internally at rates up to 2.2 μmol O2 g fresh root weight−1 h−1. In contrast, marsh species from higher zones and crop species were found to transport significantly less oxygen internally,
although rice plants were able to transport 1.4 μmol g−1 h−1. Under hypoxic conditions, low marsh species were better able to remove dissolved oxygen from the medium compared to higher
marsh species and crops. The oxygen concentration at which respiration rates declined due to limited oxygen (P
crit) was significantly lower in low marsh species compared to inland and crop species; P
crit ranged from <4 μM O2 in the low marsh species S. anglica up to 20 μM in the inland species corn. Flooding-sensitive crop species had significantly higher aerobic respiration rates
compared to flooding-tolerant species in this study. Crop species took up 3.6–6.7 μmol O2 g−1 h−1 while all but one marsh species took up <3.5 μmol O2 g−1 h−1. We conclude that oxygen transport, aerobic demand, and oxygen affinity all play important and interrelated roles in flood
tolerance and salt marsh zonation. 相似文献