全文获取类型
收费全文 | 12474篇 |
免费 | 544篇 |
国内免费 | 1951篇 |
专业分类
安全科学 | 619篇 |
废物处理 | 551篇 |
环保管理 | 1022篇 |
综合类 | 4669篇 |
基础理论 | 2322篇 |
环境理论 | 4篇 |
污染及防治 | 3089篇 |
评价与监测 | 906篇 |
社会与环境 | 1563篇 |
灾害及防治 | 224篇 |
出版年
2023年 | 154篇 |
2022年 | 442篇 |
2021年 | 439篇 |
2020年 | 393篇 |
2019年 | 340篇 |
2018年 | 393篇 |
2017年 | 464篇 |
2016年 | 493篇 |
2015年 | 493篇 |
2014年 | 679篇 |
2013年 | 1076篇 |
2012年 | 734篇 |
2011年 | 773篇 |
2010年 | 614篇 |
2009年 | 644篇 |
2008年 | 729篇 |
2007年 | 642篇 |
2006年 | 594篇 |
2005年 | 478篇 |
2004年 | 425篇 |
2003年 | 423篇 |
2002年 | 396篇 |
2001年 | 396篇 |
2000年 | 362篇 |
1999年 | 194篇 |
1998年 | 174篇 |
1997年 | 153篇 |
1996年 | 132篇 |
1995年 | 128篇 |
1994年 | 117篇 |
1993年 | 101篇 |
1992年 | 93篇 |
1991年 | 79篇 |
1990年 | 88篇 |
1989年 | 66篇 |
1988年 | 54篇 |
1987年 | 38篇 |
1986年 | 53篇 |
1985年 | 47篇 |
1984年 | 55篇 |
1983年 | 37篇 |
1982年 | 53篇 |
1981年 | 38篇 |
1980年 | 44篇 |
1979年 | 45篇 |
1978年 | 32篇 |
1973年 | 34篇 |
1972年 | 42篇 |
1971年 | 32篇 |
1969年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 953 毫秒
541.
Using environmental analytical data to estimate levels of community consumption of illicit drugs and abused pharmaceuticals 总被引:1,自引:0,他引:1
A solid phase extraction (SPE) method has been developed and applied in conjunction with a previously reported liquid chromatography tandem mass spectrometry (LC-MS-MS) procedure for the determination of illicit drugs and abused pharmaceuticals in treated wastewater and surface water samples at the ng L(-1) level. A full method validation was also performed and determined levels of analytical sensitivity were found to lie in the 1-10 ng L(-1) range using river water as a test sample matrix and a sample size of 500 mL. The developed procedure was successfully applied for the determination of the chosen analytes in wastewater treatment plants in Dublin, Ireland and rapidly expanding commuter towns in the surrounding counties. Cocaine was detected in 70% of the collected samples in the range of 25-489 ng L(-1), its primary metabolite, benzoylecognine (BZE) was also detected in the range of 22-290 ng L(-1). Other substances detected included morphine, Tempazepam and the primary metabolite of methadone. 相似文献
542.
Source to sink tracking of selected human pharmaceuticals from two Oslo city hospitals and a wastewater treatment works 总被引:4,自引:0,他引:4
Thomas KV Dye C Schlabach M Langford KH 《Journal of environmental monitoring : JEM》2007,9(12):1410-1418
The occurrence of twenty pharmaceutical compounds was quantitatively determined in effluents from two major Oslo city hospitals, Rikshospitalet and Ullev?l, along with influent, sludge and final effluent from the city's VEAS wastewater treatment works (WTW). Composite hospital effluents were collected over a twelve week period and were showed to contain paracetamol, metoprolol, diclofenac, ibuprofen, 17beta-Estradiol, estriol, estrone, oxytetracycline, tetracycline, doxycycline, chlorotetracycline, demeclocycline, trimethoprim, ciprofloxacin, sulfamethoxazole, cyclophosphamide and ifosfamide. Three pharmaceuticals were not detected above the limit of detection; cefuroxime, 17alpha-ethinylestradiol and meclocycline. Composite influent, sludge and effluent samples were collected from VEAS WTW over a seven week period. The influent into VEAS WTW contained all of the same selected substances detected in the hospital effluents, except for oxytetracycline, chlorotetracycline, demeclocycline, cyclophosphamide and ifosfamide. The percentage of pharmaceuticals entering the works from the hospitals was <10% for all of the selected compounds. VEAS sludge samples contained a different profile of substances reflecting their physico-chemical properties. Hydrophobic antibiotics, such as oxytetracycline, tetracycline and ciprofloxacin, were detected in all of the collected sludge samples. Their absence in the collected influent samples suggests that they enter the works bound to effluent particles, with the dissolved fraction observed in the hospital effluents partitioning onto particulate matter within the sewerage network. The final effluent from VEAS WTW contained reduced concentrations of many pharmaceuticals, including paracetamol, ibuprofen and sulfamethoxazole. For other compounds, such as metoprolol, diclofenac and trimethoprim, there were often higher concentrations in the effluent than the influent. These effluent concentrations represent median inputs varying from low g day(-1) (e.g. paracetamol and ibuprofen) to nearly 200 g day(-1) (e.g. metoprolol and trimethoprim) into Oslofjord. A simple risk assessment showed that the antibiotic ciprofloxacin may at times pose an acute risk to the Oslofjord aquatic environment. 相似文献
543.
HPLC-DAD, HPLC-MS/MS, GC-MS and spectrophotometric methods are employed to investigate the degradation process of sodium 1-amino-5-naphthalene sulfonate (1A5NS) aqueous solutions, when exposed to sunlight and UV-lamp (254 nm) irradiations. Experimental results show that both sunlight and 254 nm UV-lamp irradiations destroy the chemical and give rise to major degradation products, characterised by the same m/z ratios. Degradation times are lower for sunlight irradiation, for which a t(1/2) value of 137.4 min has been evaluated, in comparison with the value of t(1/2) of 26.8 min, observed for UV-lamp irradiation. The degradation pathway and the structures of the degradation products are proposed. 相似文献
544.
DFT-B3LYP method with 6-31G(**) basis set was employed to fully optimize the electronic structures of 135 polychlorinated dibenzofurans and parent compound, namely dibenzofuran. It was demonstrated that polarizability anisotropy and mean polarizability could change sensitively and systematically with chlorine number and substitution pattern. And new quantitative structure-activity relationships (QSARs) focused on the binding affinities of aryl hydrocarbon receptor (AhR), aryl hydrocarbon hydroxylase (AHH) and 7-ethoxyresorufin O-deethylase (EROD) induction potencies of PCDFs were developed. It was concluded that polarizability anisotropy in conjunction with hyperpolarizabilties and hyper-order electric moments, e.g. octupole moments could well interpret the variation of toxicity of different congeners and dispersion interaction should be the leading form among various interactions. Although the terms of hyperpolarizabilities and hyper-order electric moments were not the same significant ones as polarizability anisotropy, the long-range interactions characterized by them should not be ignored in explaining the toxicity. 相似文献
545.
Evaluation of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen leaching in undisturbed soil columns 总被引:3,自引:0,他引:3
The application of nitrogen fertilizers leads to various ecological problems such as nitrate leaching. The use of nitrification inhibitors (NI) as nitrate leaching retardants is a proposal that has been suggested for inclusion in regulations in many countries. In this study, the efficacy of the new NI, 3,4-dimethyl pyrazole phosphate (DMPP), was tested under simulated high-risk leaching situations in two types of undisturbed soil columns. The results showed that the accumulative leaching losses of soil nitrate under treatment of urea with 1.0% DMPP, from columns of silt loam soil and heavy clay soil, were 66.8% and 69.5% lower than those soil columns tested with regular urea application within the 60 days observation, respectively. However, the losses of ammonium leaching were reversely increased 9.7% and 6.7% under the former treatment than the latter one. Application of regular urea with 1.0% DMPP addition can reduce about 59.3%-63.1% of total losses of inorganic nitrogen via leaching. The application of DMPP to urea had stimulated the inhibition effects of DMPP on the ammonium nitrification process in the soil up to 60 days. It is proposed that the DMPP could be used as an effective NI to control inorganic N leaching losses, minimizing the risk of nitrate pollution in shallow groundwater. 相似文献
546.
Adamo P Crisafulli P Giordano S Minganti V Modenesi P Monaci F Pittao E Tretiach M Bargagli R 《Environmental pollution (Barking, Essex : 1987)》2007,146(2):392-399
Lobes of the lichen Pseudevernia furfuracea (L.) Zopf and shoots of the moss Hypnum cupressiforme Hedw. were subjected to different treatments (water washing, oven drying, HNO3 washing, NH4-oxalate extraction) to assess the influence of vitality on accumulation efficiency, during a 6-week exposure in bags in two Italian cities, Trieste and Naples. No trend emerged between treatments, in terms of accumulation ability, for major and trace elements. Only water-washed lichens showed an increased C and N content after exposure in both cities. Element concentrations generally reached higher values in mosses than in lichens, especially for Al, Fe, and Zn (both cities), and for Cu, Mg and Na (Naples). Surface development strongly influenced accumulation capacity of the biomonitors. Quartzose and cation exchange filters revealed, on a weight basis, a poor performance. In urban environments, surface interception of atmospheric particulate seems to play a major role in accumulation, irrespective of organism vitality. 相似文献
547.
Real time remote monitoring of air pollutants and their online transmission to the web using internet protocol 总被引:1,自引:0,他引:1
Anjaneyulu Y Jayakumar I Bindu VH Rao PV Sagareswar G Ramani KV Rao TH 《Environmental monitoring and assessment》2007,124(1-3):371-381
Recent advances in both information and sensor technologies have enabled the development of Real Time Remote Monitoring (RTRM)
capabilities for environmental management. An online and real time remote monitoring system for air pollution has been designed
and installed at a traffic police station at Punjagutta in Hyderabad, India. The system is optimized using electrochemical
sensors and a real time particulate matter analyzer. The system also monitors meteorological parameters such as temperature,
humidity, rainfall, barometric pressure, wind speed and wind direction. The system periodically monitors both pollution and
meteorological parameters at pre- programmed intervals of hr during peak periods and 1 hr during non peak periods of the day and continuously uploads to a predestinated web site (www.appcb.org/home.htm)
using File Transfer Protocol. The web site renders a quick, simple and graphical display of air pollution levels and meteorological
parameters and their significance to humans. The present paper highlights design considerations of a pollution monitoring
system, system hardware and software requirements and practical limitations and future directions for real time remote monitoring
of air pollution. 相似文献
548.
Leachate recirculation or liquid injection in municipal solid waste landfills offers economic and environmental benefits. The key objective of this study was to carry out numerical evaluation of key design variables for leachate recirculation system consisting of vertical wells. In order to achieve the objective, numerical modeling was carried out using the finite-element model HYDRUS-2D. The following design parameters were evaluated by simulating liquid pressure head on the liner and the wetted width of the waste under steady-state flow conditions: (1) hydraulic conductivities of the waste and vertical well backfill; (2) liquid injection rate and dosing frequency; (3) well diameter, screen height and screen depth; and (4) hydraulic conductivity of the leachate collection system, slope of the leachate collection system and spacing of the leachate collection pipes. The key findings of this study are as follows. The well diameter, hydraulic conductivity of the well drainage pack, and screen height and screen depth of the well have very little effect on the wetted width for a given liquid flux. The wetted width and the injection pressure for a given liquid flux decrease with the increase in the hydraulic conductivity of the waste. The pressure head on the liner increases with the decrease in the vertical distance between the bottom of the well screen and the top of leachate collection system. The liquid injection flux increases with the decrease in hydraulic conductivity of the leachate collection system. Unlike sand (k approximately 10(-4)m/s), pea gravel (k approximately 0.01 m/s) resulted in less than 0.3m pressure head on the liner for all simulations carried out in this study. 相似文献
549.
Francois V Feuillade G Matejka G Lagier T Skhiri N 《Waste management (New York, N.Y.)》2007,27(9):1259-1272
The purpose of this study is to determine the impact of leachate recirculation on the degradation of municipal solid wastes (bioreactor concept). The study was carried out using columns containing approximately 50 kg of waste, in order to follow waste degradation over a limited time. Three types of waste were studied: fresh waste of standard composition, fresh waste of fermentable composition and some 8-yr-old waste extracted from a site in France. Measurement of the global parameters, such as chemical oxygen demand (COD), volatile acidity, alkalinity, leachate conductivity, methane potential of the wastes and biogas production monitoring (volume of CO2 and CH4 produced), were carried out. The quantity of oxydizable matter and biogas production was increased by the leachate recirculation, and the duration of the first degradation phases was reduced in all cases. Chloride, ammonium and organic pollution accumulation was observed according to the duration of recirculation. After 400 days of degradation, waste stabilization seemed to be reached for all of the recirculated columns (COD<300 mg/L O2, and methane potential reached). 相似文献
550.
Effective removal of coordinated copper from wastewater using a new dithiocarbamate-type supramolecular heavy metal precipitant 总被引:1,自引:0,他引:1
A new dithiocarbamate-type heavy metal precipitant, sodium 1,3,5-hexahydrotriazinedithiocarbamate (HTDC), was prepared and used to remove coordinated copper from wastewater. In the reported dithiocarbamate-type precipitants, HTDC possesses the highest percentage of the effective functional groups. It could effectively precipitate copper to less than 0.5 mg l−1 from both synthetic and actual industrial wastewater containing CuEDTA in the range of pH 3–9. UV–vis spectral investigation and elemental analysis suggested that the precipitate was a kind of coordination supramolecular compound, [Cu3(HTDC)2]n. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) indicated that the supramolecular precipitate was non-hazardous and stable in weak acid and alkaline conditions. Tests of an anion exchange resin D231 provided a clue to simultaneously remove excess HTDC and residual CuEDTA in practical process of wastewater treatment. 相似文献