全文获取类型
收费全文 | 12212篇 |
免费 | 95篇 |
国内免费 | 92篇 |
专业分类
安全科学 | 309篇 |
废物处理 | 554篇 |
环保管理 | 1485篇 |
综合类 | 2649篇 |
基础理论 | 2705篇 |
环境理论 | 5篇 |
污染及防治 | 3229篇 |
评价与监测 | 782篇 |
社会与环境 | 618篇 |
灾害及防治 | 63篇 |
出版年
2022年 | 126篇 |
2021年 | 131篇 |
2020年 | 76篇 |
2019年 | 87篇 |
2018年 | 199篇 |
2017年 | 163篇 |
2016年 | 270篇 |
2015年 | 216篇 |
2014年 | 294篇 |
2013年 | 898篇 |
2012年 | 336篇 |
2011年 | 485篇 |
2010年 | 377篇 |
2009年 | 424篇 |
2008年 | 485篇 |
2007年 | 546篇 |
2006年 | 475篇 |
2005年 | 378篇 |
2004年 | 390篇 |
2003年 | 399篇 |
2002年 | 359篇 |
2001年 | 443篇 |
2000年 | 320篇 |
1999年 | 209篇 |
1998年 | 118篇 |
1997年 | 123篇 |
1996年 | 111篇 |
1995年 | 157篇 |
1994年 | 156篇 |
1993年 | 129篇 |
1992年 | 134篇 |
1991年 | 149篇 |
1990年 | 122篇 |
1989年 | 127篇 |
1988年 | 133篇 |
1987年 | 114篇 |
1986年 | 84篇 |
1985年 | 100篇 |
1984年 | 126篇 |
1983年 | 126篇 |
1982年 | 125篇 |
1981年 | 99篇 |
1980年 | 93篇 |
1979年 | 107篇 |
1978年 | 90篇 |
1977年 | 84篇 |
1976年 | 78篇 |
1975年 | 91篇 |
1974年 | 101篇 |
1965年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
631.
Maria das Graças Lins Brandão Gustavo Pereira Cosenza Flávia Liparini Pereira Ariela Silva Vasconcelos Christopher William Fagg 《Environmental monitoring and assessment》2013,185(8):7013-7023
Plants continue to be an important source of new bioactive substances. Brazil is one of the world’s mega-diverse countries, with 20 % of the world’s flora. However, the accelerated destruction of botanically rich ecosystems has contributed to a gradual loss of native medicinal species. In previous study, we have observed a fast and intensive change in trade of medicinal plants in an area of Amazon, where human occupation took place. In this study, we surveyed 15 public markets in different parts of Brazil in search of samples of 40 plants used in traditional medicine and present in first edition of Brazilian Official Pharmacopoeia (FBRAS), published in 1926. Samples of plants commercialized as the same vernacular name as in Pharmacopoeia were acquired and submitted to analysis for authentication. A total of 252 plant samples were purchased, but the laboratory analyses showed that only one-half of the samples (126, 50.2 %) were confirmed as the same plant species so named in FBRAS. The high number of unauthenticated samples demonstrates a loss of knowledge of the original native species. The proximity of the market from areas in which the plant occurs does not guarantee that trade of false samples occurs. The impact of the commerce of the substitute species on their conservation and in public health is worrying. Strategies are necessary to promote the better use and conservation of this rich heritage offered by Brazilian biodiversity. 相似文献
632.
R. Maurício C. J. Dias N. Jubilado F. Santana 《Environmental monitoring and assessment》2013,185(10):8125-8133
In this report, the development of an online, noninvasive, measurement method of the biofilm thickness in a liquid phase is presented. The method is based in the analysis of the ultrasound wave pulse-echo behavior in a liquid phase reproducing the real reactor conditions. It does not imply the removal of the biomass from the support or any kind of intervention in the support (pipes) to detect and perform the measurements (non-invasiveness). The developed method allows for its sensor to be easily and quickly mounted and unmounted in any location along a pipe or reactor wall. Finally, this method is an important innovation because it allows the thickness measurement of a biofilm, in liquid phase conditions that can be used in monitoring programs, to help in scheduling cleaning actions to remove the unwanted biofilm, in several application areas, namely in potable water supply pipes. 相似文献
633.
J. L. F. Angeli T. H. Trevizani A. Ribeiro E. C. Machado R. C. L. Figueira B. Markert S. Fraenzle S. Wuenschmann 《Environmental monitoring and assessment》2013,185(10):8333-8342
Concentrations of arsenic and four additional trace elements (Cu, Cr, Ni, and Zn) were determined by inductively coupled plasma–optical emission spectrometry in the muscular tissue of the yellow catfish (Cathorops spixii) and the urutu catfish (Genidens genidens) from Paranaguá Estuarine Complex, Brazil (PEC). The PEC can be characterized by an environment of high ecological and economic importance in which preserved areas of rainforest and mangroves coexist with urban activities as ports and industries. The average concentrations (in milligram per kilogram dry weight) of elements in the muscle tissue of C. spixii are as follows: Zn (31), As (17), Cu (1.17), Cr (0.62), and Ni (0.28). Similar concentrations could be found in G. genidens with exception of As: Zn (36), As (4.78), Cu (1.14), Cr (0.51), and Ni (0.14). Fish from the geographic northern rural region (Guaraqueçaba–Benito) display higher As concentrations in the muscle tissues than fish found in the south-western (urban) part of the PEC. An international comparison of muscle tissue concentrations of trace elements in fish was made. Except for Ni in C. spixii, a tendency of decrease in element concentration with increasing size (age) of the fish could be observed. According to the National Health Surveillance Agency of Brazil, levels of Cr and As exceeded the permissible limits for seafood. An estimation of the provisional tolerable weekly intake of As was calculated with 109 % for C. spixii and with 29 % for G. genidens. 相似文献
634.
635.
C. M. Oliveira M. F. Camões P. Bigus A. A. Fachado R. B. Silva 《Environmental monitoring and assessment》2015,187(6):380
In this work, particulate matter was collected using an active sampling system consisting of a PM10 (<10 μm) inlet coupled to a multifold device containing six channels, connected to a vacuum pump. Each channel was equipped with a filter holder fitted with adequately chosen filters. The system was fixed on a metallic structure, which was placed on the roof of the laboratory building, at the Faculty of Sciences, in Lisbon. Sampling took place under flow-controlled conditions. Aerosols were extracted from the filters with water, in defined conditions, and the water-soluble fraction was quantified by ion chromatography (IC) for the determination of inorganic anions (Cl?, NO3 ? and SO4 2?). Equivalent sampling through the various channels was validated. Validation was based on the metrological compatibility of the content results for the various filters. Ion masses are metrologically equivalent when their absolute difference is smaller than the respective expanded uncertainty. When this condition is verified, the studied multifold device produces equivalent samples. 相似文献
636.
Alam R Munna G Chowdhury MA Sarkar MS Ahmed M Rahman MT Jesmin F Toimoor MA 《Environmental monitoring and assessment》2012,184(1):573-580
In rural areas in Bangladesh, groundwater is the principal source of water supply. This underground water is available in
considerable amount in shallow aquifers. It is free from pathogenic microorganisms and hence water-borne diseases. In plain
lands, other than hilly areas, water supply to 97% rural population comes from tube-wells, which is regarded to be a phenomenal
achievement in preserving public health. Besides, a dependable water supply system all throughout the country is offset by
two factors: (a) high salinity in surface plus groundwater in coastal areas; (b) want of suitable groundwater aquifers in
hilly areas and the high cost of setting up tube-wells due to deep underground water table and stony layers. However, presence
of arsenic in underground water now poses a serious threat to the success once made in water supply by setting up of manually
operated tube-wells in the village areas—the achievement is now on the brink of total collapse. In about 61 districts out
of 64, presence of arsenic exceeds a quantity of 0.05 mg/1, a permissible limit as per Bangladeshi water quality standard.
Harvesting rainwater can be a pragmatic solution to this problem, which is common in many places in Sylhet especially in the
hilly areas on the north eastern part of the city. This can be an alternative source of drinking water because of availability
of rainwater from March to October. Heavy rain occurs from end of May till mid September, which is commonly known as the rainy
season. This paper focuses on the possibility of harvesting rainwater in rural communities and thickly populated urban areas
of Sylhet. It also demonstrates the scopes of harvesting rainwater using simple and low-cost technology. With setting up of
a carefully planned rainwater storage tank, a family can have all of its drinking water from rain. Planned use of rainwater
through rainwater harvesting in the roof catchments may fulfill the entire annual domestic water demand of a family in the
rural areas of Bangladesh. 相似文献
637.
Mehmet Sinan Bilgili Gamze Varank Elif Sekman Selin Top Didem Özçimen Remziye Yazıcı 《Environmental Modeling and Assessment》2012,17(3):289-300
Since phenols and phenolic compounds in many industrial wastewaters are toxic organic contaminants for humans and aquatic
life, to remove these compounds via the most efficient way is very important for environmental remediation treatment. In this
context, almost all of the isotherm models (Freundlich, Langmuir, Temkin, Redlich–Peterson, Sips, and Khan) for adsorption
in the literature were applied to explain the adsorption mechanism of 4-chlorophenol on activated carbon in this study. Also
theoretical modeling data were obtained using model equations; interpolation and analysis of variance were made to compare
data by using statistics software. In addition, the thermodynamic and kinetic studies for adsorption mechanism were included
in the article. The adsorption of 4-chlorophenol on activated carbon fits well to the pseudo-first-order kinetic model than
the pseudo-second-order, intraparticular diffusion and Bangham models. It is also indicated that 4-chlorophenol adsorption
by granular activated carbon would be attributed to a type of transition between physical and chemical adsorption rather than
a pure physical or chemical adsorption process. As a result, an environmental remediation problem and the adsorption mechanism
on activated carbon that can be regarded as a solution to this problem are described and explained using the mathematical
models and calculations in this study. 相似文献
638.
I-Ting Hsieh Hin-Kiu Mok Fung-Chi Ko S. Açik 《Environmental monitoring and assessment》2013,185(3):2269-2279
This study is the first measurement of trace elements in sipunculan and their surrounding sediments. The bioaccumulation characteristics of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), and zinc (Zn) were analyzed and compared in two sipunculan species, Sipuncula nudus and Siphonosoma vastum, which were collected from seagrass beds and wetlands in Taiwan. The sipunculan and sediment samples were analyzed using an inductively coupled plasma mass spectrometer. Both sipunculan in the wetlands and seagrass beds had a high Cu bioaccumulation mechanism. Multivariate analysis, principle component analysis, and partial least squares for discriminant analysis of trace element levels and bioaccumulation factors were used to distinguish the element distributions that corresponded to the two habitats (seagrass beds and wetlands). Different levels of certain trace elements in these two sipunculan species may result not only from the environmental factors of various habitats but also from the accumulation characteristics of various species. The As, Cd, Cr, Cu, Hg, and Zn concentrations were markedly lower in sipunculan than in other invertebrates from the adjacent polluted regions. The public health issues regarding the consumption of sipunculan are also discussed. 相似文献
639.
José A. Murillo Pulgarín Luisa F. García Bermejo Armando Carrasquero Durán 《Environmental monitoring and assessment》2013,185(1):573-580
A flow injection analysis method based on ion chromatography and luminol chemiluminescence detection was used for the simultaneous determination of copper (II) and cobalt (II) trace levels in soils and sediments following microwave-assisted acid digestion. Detection was based on chemiluminescence (CL) of the luminol–perborate system in an alkaline medium, which is catalyzed by both transition metals. The concentration and pH of the eluent (oxalic acid) was found to affect CL intensities and retention times, both of which were inversely proportional to the oxalic acid concentration. The calibration curves for both metal ions were linear and allowed a limit of detection of 0.003 μg l?1 for cobalt (II) and 0.014 μg l?1 for cooper (II) to be calculated. The proposed method was successfully used to determine both metal ions in certified reference materials of stream and river sediments and soil samples. Based on the results, the determination is free of interferences from the usual concomitant ions. 相似文献
640.
Rui Galhano dos Santos Noemi F. Acero Sandro Matos Ricardo Carvalho Mário Vale Ana C. Marques João C. Bordado Maria M. Mateus 《Journal of Polymers and the Environment》2018,26(1):91-100
The use of petroleum-derived products should be avoided regarding the principles of green and sustainable chemistry. The work reported herein, is aimed at the liquefaction of pine shavings for the production of an environmentally-friendly polyol suitable to be used in the formulations of sprayable polyurethane foams. The biopolyols were obtained in high yield and were used to replace those derived from fossil sources, to produce more “greener” polyurethane foams and therefore, less dependent on petroleum sources, since the polyol component was substituted by products resulting from biomass liquefaction. The partial and fully exchange of the polyols was accomplished, and the results compared with a reference foam. The foams were afterward, chemical, physical, morphological, and mechanically characterized. The complete replacement of polyether polyol and polyol polyester has presented some similar characteristics as that used as a reference, validating that the path chosen for the development of more sustainable materials is on the right track for the contribution to a cleaner world. 相似文献