全文获取类型
收费全文 | 578篇 |
免费 | 15篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 43篇 |
环保管理 | 63篇 |
综合类 | 76篇 |
基础理论 | 124篇 |
环境理论 | 1篇 |
污染及防治 | 187篇 |
评价与监测 | 47篇 |
社会与环境 | 35篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 9篇 |
2022年 | 26篇 |
2021年 | 29篇 |
2020年 | 15篇 |
2019年 | 21篇 |
2018年 | 31篇 |
2017年 | 22篇 |
2016年 | 22篇 |
2015年 | 22篇 |
2014年 | 40篇 |
2013年 | 45篇 |
2012年 | 36篇 |
2011年 | 52篇 |
2010年 | 26篇 |
2009年 | 28篇 |
2008年 | 35篇 |
2007年 | 29篇 |
2006年 | 25篇 |
2005年 | 25篇 |
2004年 | 8篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1991年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有598条查询结果,搜索用时 15 毫秒
41.
Candice DeLeo Caio Augusto Pinotti Maria do Carmo Gonçalves Sachin Velankar 《Journal of Polymers and the Environment》2011,19(3):689-697
Plasticized starch (PLS) is a renewable, degradable, and inexpensive polymer, but it suffers from poor mechanical properties.
The mechanical properties can be improved by blending PLS with polyolefins, nonetheless, at high PLS content, the mechanical
properties remain poor. Here we show that addition of clay can greatly improve the mechanical properties of PLS/polypropylene
blends at high starch content. Unmodified and organically modified montmorillonite clays, MMT and Cloisite 30B respectively,
were added to blends of glycerol-plasticized starch and polypropylene, compatibilized using maleated polypropylene. TEM indicates
that MMT is well dispersed in the PLS phase of the blends, while Cloisite 30B is located both within the PLS phase as well
as at the interface between PLS and PP. At high PLS content, the addition of clay increased the tensile strength and tensile
modulus by an order of magnitude, while reducing the ultimate elongation only slightly. Such improvements are attributable
to both the addition of clay as a reinforcing component, as well as to the change in the two phase morphology due to addition
of clay. 相似文献
42.
Bruna Castro Porto Pedro Esteves Duarte Augusto Marcelo Cristianini 《Journal of Polymers and the Environment》2015,23(3):392-399
Arabic gum (AG) is the most common emulsifier used for beverage emulsions. Cashew tree gum (CG) is a biological macromolecule that has been proposed as a substitute for the AG, although their technological properties comparison is still necessary. The aim of this study was to evaluate an isolation method for CG, and then evaluate CG technological properties in comparison to AG. The CG isolation methodology was improved using a small solvent amount. CG zeta-potential ranged from +8.0 mV (pH 2) to ?9.7 mV (pH 5), while the electric charge in solution of AG ranged from ?2.7 mV (pH 2) to ?28.6 mV (pH 6). As compared to AG, the CG showed a 50 % higher swelling, a 36 % lower oil absorption capacity, a slightly lower (4–8 %) solubility and lower consistency. CG is a feasible polyelectrolyte, promotes lower consistency solutions, and exhibits good swelling property. 相似文献
43.
The activity of 210Po and 210Pb was determined in mussels of the same size (3.5-4.0 cm shell length) sampled monthly over a 17-month period at the Atlantic coast of Portugal. Average radionuclide concentration values in mussels were 759 ± 277 Bq kg−1 for 210Po (range 460-1470 Bq kg−1 dry weight), and 45 ± 19 Bq kg−1 for 210Pb (range 23-96 Bq kg−1 dry weight). Environmental parameters and mussel biometric parameters were monitored during the same period. Although there was no seasonal variation of radionuclide concentrations in sea water during the study period, the concentration of radionuclide activity in mussels varied seasonally displaying peaks of high concentrations in winter and low concentrations in summer. Analysis of radionuclide data in relation to the physiological Condition Index of mussels revealed that 210Po and 210Pb activities in the mussel (average activity per individual) remained nearly constant during the investigation period, while mussel body weight fluctuated due to fat storage/expenditure in the soft tissues. Similar variation of radionuclide concentrations was observed in mussels transplanted from the sea coast into the Tejo Estuary. However, under estuarine environmental conditions and with higher food availability throughout the year, transplanted mussel Condition Index was higher than in coastal mussels and average radionuclide concentrations were 210 ± 75 Bq kg−1 (dry weight) for 210Po and 10 ± 4 Bq kg−1 (dry weight) for 210Pb, therefore lower than in coastal mussels with similar shell length. It is concluded that the apparent seasonal fluctuation and inter-site difference of radionuclide concentrations were mostly caused by mussel body weight fluctuation and not by radionuclide body burden fluctuation. This interpretation can be extended to the apparent seasonal fluctuation in concentrations of lipophilic and lipophobic contaminants in mussels, and provides an explanation for occasional high concentrations of 210Po and man-made contaminants measured in mussels far from pollution sources. 相似文献
44.
Bruno Nunes Ana Raquel Barbosa Sara C. Antunes Fernando Gonçalves 《Environmental science and pollution research international》2014,21(9):6258-6262
The simultaneous presence of distinct compounds in the aquatic environment can be causative of various toxicological interactions. This scenario challenges ecotoxicologists, since the assessment of toxicological effects caused by the simultaneous presence of multiple substances is by far more complicated. An illustrative example can be given by mentioning the anticholinesterasic compounds: by studying the level of cholinesterase impairment of an exposed organism, it is possible to ascertain the level of exposure to all anticholinesterasics (despite their chemical classes and natures) that the organism was subjected to. In this work, we describe the effects of three chemically different, albeit mechanistically, and toxicologically similar compounds (copper, chlorfenvinphos, and pyridostigmine) on cholinesterases of the fish Gambusia holbrooki. The results showed that the combinatorial effects may be of considerable extent, even for levels of exposure that are close to the ones already reported in the wild, for each isolated compound. 相似文献
45.
This paper presents an overview of cell phone recycling programs currently available in the United States. At the same time, it also provides analyses of the current recycling situation and possible recycling alternatives for Brazil. Although there are several recycling options in the United States, collection rates are still only 10% of all potential devices because customers are not aware of these possibilities. The whole system is financially based on reselling refurbished cell phones and recycled materials to developing countries which represent an effective and strong market. Several recyclers offer funds to collection partners who are either charities or who work with charities while obtaining the materials that they need in order to run their operations. A mobile phone recycling system for Brazil considering the United States experience and the Extended Producer Responsibility (EPR) principle is suggested. A deposit/refund/advance-recycling fee is proposed which might be implemented as a voluntary industrial initiative managed by PRO Brazil, a producer responsibility organization. One widespread public–private agreement will integrate all mobile phone stakeholders, and environmental education actions and promotional events will promote citizen’s participation. 相似文献
46.
Bruno Nunes Fátima Brandão Tânia Sérgio Sara Rodrigues Fernando Gonçalves Alberto Teodorico Correia 《Environmental science and pollution research international》2014,21(12):7501-7511
Flatfish species, such as the turbot (Scophthalmus maximus), are common targets for toxic effects, since they are exposed through the food chain (ingestion of contaminated preys) and are in direct contact with the waterborne contaminant and sediments. Furthermore, these fish species live in close proximity to interstitial water that frequently dissolves high amounts of contaminants, including metals. Despite this significant set of characteristics, the present knowledge concerning flatfish contamination and toxicity by metals is still scarce. To attain the objective of assessing the effects of metals on a flatfish species, S. maximus specimens were chronically exposed to lead, copper and zinc, at ecologically relevant concentrations, and biochemical (oxidative stress: catalase and glutathione S-transferases activities, and lipid peroxidation; neurotoxicity: cholinesterase activity) parameters were assessed on selected tissues (gills and liver). Copper had no significant effects on all tested parameters; lead was causative of significant increases in liver GSTs activities and also in lipoperoxidation of gill tissue; exposure to zinc caused a significant increase in catalase activity of gill tissue. None of the tested metals elicited noteworthy effects in terms of neurotoxicity. The obtained results showed that only the metal lead is of some environmental importance, since it was able to cause deleterious modifications of oxidative nature at relevant concentrations. 相似文献
47.
Morello Thiago Fonseca da Silva e Silva Luís Fernando 《Environmental Economics and Policy Studies》2023,25(2):115-142
Environmental Economics and Policy Studies - To test if tax return can effectively and efficiently increase the acceptance of externality taxation, a laboratory experiment with a negative... 相似文献
48.
Rivelino M. Cavalcante Francisco W. Sousa Ronaldo F. Nascimento Edilberto R. Silveira George S.S. Freire 《Journal of environmental management》2009,90(2):328-335
This investigation represents the first environmental diagnosis of the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments from a tropical mangrove in Fortaleza, northeastern Brazil. Sediment cores from six sampling stations in the Cocó and Ceará Rivers were retrieved in June-July 2006 to determine 17 priority PAHs. The total PAH concentrations (ΣPAHs) ranged from 3.04 to 2234.76 μg kg?1(Cocó River) and from 3.34 to 1859.21 μg kg?1 (Ceará River). These levels are higher than those of other cities with more industrial development. PAH concentrations did not reach probable effect levels (PELs). However, from 4.5 to 87.5% of individual PAH concentrations can occasionally cause adverse biological effects for aquatic organisms. The PAH molecular ratios indicate that the PAHs in the sediment core were derived mainly from petroleum, wood, and charcoal combustion (pyrogenic source), and that atmospheric deposition and urban runoff may serve as important pathways for PAH input to the sediment. Clearly, the ΣPAHs in sediments collected in the Cocó and Ceará Rivers indicate that ongoing pollution is more severe than past pollution. 相似文献
49.
Predictive value of cardiovascular parameters in stages 1 and 2 of twin-to-twin transfusion syndrome
50.
Marcela Rodrigues De Camargo Luís Fernando Barbisan Meire França Martinez Carla Adriene Da Silva Franchi João Lauro Viana De Camargo Ana Lúcia Tozzi Spinardi-Barbisan 《Journal of environmental science and health. Part. B》2013,48(7):607-613
The noxious effects of low or effective dose exposure to single or mixed pesticides on macrophage activity and the lymphohematopoietic organs were investigated. Male Wistar rats were orally exposed to dichlorvos, dicofol, endosulfan, dieldrin and permethrin, either as single or combined mixtures during a 28-day study containing eight groups: one group received a semipurified diet (non-treated); two groups received a semipurified diet containing low dose mixture (dieldrin 0.025 mg/kg, endosulfan, 0.6 mg/kg, dicofol 0.22 mg/kg, dichlorvos 0.23 mg/kg, permethrin 5 mg/kg) or an effective dose mixture (dichlorvos 2.3 mg/kg, dicofol 2.5 mg/kg, endosulfan 2.9 mg/kg, dieldrin 0.05 mg/kg and permethrin 25.0 mg/kg), respectively; the other five groups received a semipurified diet containing each single pesticide in effective doses. At sacrifice, the thymus, spleen, mesenteric lymph nodes, Payer's patches and bone marrow were removed for histological analysis. Peritoneal macrophages were obtained to determine the phagocytosis and spreading indexes and tumoral necrosis factor alpha (TNF-α), nitric oxide (NO) and H2O2 production. Exposure to pesticide mixtures did not alter the percentage of macrophage phagocytosis and spreading, TNF-α production or the NO and H2O2 release when compared to the non-treated group. Neither was there any apparent evidence that a pesticide mixture at low or effective doses altered the histological structure of the lymphohematopoietic organs. The findings indicate that short-term treatment with pesticide mixtures did not induce an apparent immunotoxic effect in male Wistar rats. 相似文献