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171.
Rafael Fleischman Ran Amiel Jan Czerwinski Andreas Mayer Leonid Tartakovsky 《环境科学学报(英文版)》2018,30(5):273-286
Retrofitting older vehicles with diesel particulate filter(DPF) is a cost-effective measure to quickly and efficiently reduce particulate matter emissions. This study experimentally analyzes real-world performance of buses retrofitted with CRT DPFs. 18 in-use Euro III technology urban and intercity buses were investigated for a period of 12 months. The influence of the DPF and of the vehicle natural aging on buses fuel economy are analyzed and discussed. While the effect of natural deterioration is about 1.2%–1.3%, DPF contribution to fuel economy penalty is found to be 0.6% to 1.8%, depending on the bus type. DPF filtration efficiency is analyzed throughout the study and found to be in average 96% in the size range of 23–560 nm. Four different load and non-load engine operating modes are investigated on their appropriateness for roadworthiness tests. High idle is found to be the most suitable regime for PN diagnostics considering particle number filtration efficiency. 相似文献
172.
An experiment under laboratory conditions was conducted to test the hypothesis that development and growth of copepodite
stages in Calanus chilensis are temperature-dependent and not subject to food shortage in the upwelling area of the Humboldt Current, northern Chile.
Field data obtained from June 1994 to May 1995 in Bahía Mejillones (23°S) were used to define four combinations of temperature
and food under which copepodites were reared from Stage CIII to adulthood. The high temperature was 18.1 °C and the low temperature
13.1 °C, whereas the high food level was in the range of 6.8 to 24.8 μg l−1 chlorophyll a and the low level 1.0 to 6.8 μg l−1 chlorophyll a. As food a mixture of three unknown species of phytoflagellates and the diatom Navicula cryptocephala was used. This phytoplankton was initially obtained from the same sampling sites as copepods and kept in f/2 media at stable levels and composition throughout the experiment. The development rate (1/t), estimated from the time (t) elapsing between Stage CIV and adult, was significantly affected by both temperature and food, although low-food effects
were much more remarkable. Low-food conditions also significantly reduced body length and “structural” (lipid-discounted)
body mass at adulthood, while temperature only affected body length. The weight-specific growth rate was also affected by
food and temperature, but again food effects were much more drastic. The results indicate that C. chilensis is a highly sensitive species to lack of food, and is possibly subject to food shortage during its annual cycle in the coastal
upwelling area of northern Chile. Food limitation may help explain the seasonal pattern of adult size reported by previous
studies in the area and the lack of consistence between the number of generations predictable from a temperature-dependent
model and that observed in the field during the annual cycle.
Received: 10 September 1996 / Accepted: 29 October 1996 相似文献
173.
Jud Harvey Jesus Gomez‐Velez Noah Schmadel Durelle Scott Elizabeth Boyer Richard Alexander Ken Eng Heather Golden Albert Kettner Chris Konrad Richard Moore Jim Pizzuto Greg Schwarz Chris Soulsby Jay Choi 《Journal of the American Water Resources Association》2019,55(2):369-381
Downstream flow in rivers is repeatedly delayed by hydrologic exchange with off‐channel storage zones where biogeochemical processing occurs. We present a dimensionless metric that quantifies river connectivity as the balance between downstream flow and the exchange of water with the bed, banks, and floodplains. The degree of connectivity directly influences downstream water quality — too little connectivity limits the amount of river water exchanged and leads to biogeochemically inactive water storage, while too much connectivity limits the contact time with sediments for reactions to proceed. Using a metric of reaction significance based on river connectivity, we provide evidence that intermediate levels of connectivity, rather than the highest or lowest levels, are the most efficient in removing nitrogen from Northeastern United States’ rivers. Intermediate connectivity balances the frequency, residence time, and contact volume with reactive sediments, which can maximize the reactive processing of dissolved contaminants and the protection of downstream water quality. Our simulations suggest denitrification dominantly occurs in riverbed hyporheic zones of streams and small rivers, whereas vertical turbulent mixing in contact with sediments dominates in mid‐size to large rivers. The metrics of connectivity and reaction significance presented here can facilitate scientifically based prioritizations of river management strategies to protect the values and functions of river corridors. 相似文献
174.
Paul W. Hadley Peter Gathungu Juan T. Koponen Perry Myers Jesus I. Sotelo 《补救:环境净化治理成本、技术与工艺杂志》2014,24(4):7-26
In 1976, the discovery of the Love Canal Superfund Site in New York thrust environmental cleanups into the forefront of the national conscience and essentially launched the remediation industry. Since then, vast efforts have been devoted to improving site remediation. Despite the attention given to key subject areas, such as site characterization, risk assessment, and remediation technologies, relatively little attention has been given to the objectives set forth for conducting cleanups, and they have generally not been rigorously evaluated in the literature. Several of the more common objectives for remediation projects are discussed. © 2014 Wiley Periodicals, Inc. 相似文献
175.
Porto Rafael Silveira Pinheiro Rafael Silvio Bonilha Rath Susanne 《Environmental science and pollution research international》2021,28(42):59040-59049
Environmental Science and Pollution Research - Benzimidazoles are anthelmintics frequently used in sheep farming due to the high susceptibility of these animals to parasitic diseases. Sheep excreta... 相似文献
176.
dos Santos Clécia Andrade de Souza Cruz Daiane Requião da Silva Wenes Ramos de Jesus Gleyce Kelly Santos Alessandra Ferreira da Cunha Graziele Costa Wisniewski Alberto Romão Luciane Pimenta Cruz 《Environmental science and pollution research international》2021,28(19):23929-23945
Environmental Science and Pollution Research - A simple, efficient, environmentally friendly, and inexpensive synthesis route was developed to obtain a magnetic nano-hybrid (GH) based on graphene... 相似文献
177.
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179.
The evolution over time of the levels and distribution of dichlorodiphenyltrichloroethane (DDT) in water, surface sediments, and fish from the River Cinca (Spain), a tributary of the River Ebro, during the period 1999 to 2004, was investigated by means of gas chromatography coupled with mass spectrometry. The sampling site corresponded to a point downstream from Monzón, a heavily industrialized town with drainage into the river. This river has historically been a source of emissions of DDT and its metabolites. The highest levels were found in 1999 and 2000, although the concentrations of organic compounds in sediments and fish have decreased since then. The levels of DDT in water were below the quantification limit during the period of study. The average composition of DDT isomers measured in sediments and fish showed the prevalence of p,p'-DDE, the product of aerobic degradation of p,p'-DDT. Concentrations in fish were compared with sediment samples, and high quotients indicate that they are highly bioavailable. 相似文献
180.