全文获取类型
收费全文 | 962篇 |
免费 | 10篇 |
国内免费 | 31篇 |
专业分类
安全科学 | 38篇 |
废物处理 | 86篇 |
环保管理 | 80篇 |
综合类 | 72篇 |
基础理论 | 163篇 |
环境理论 | 1篇 |
污染及防治 | 351篇 |
评价与监测 | 157篇 |
社会与环境 | 50篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 11篇 |
2022年 | 120篇 |
2021年 | 107篇 |
2020年 | 20篇 |
2019年 | 38篇 |
2018年 | 44篇 |
2017年 | 50篇 |
2016年 | 66篇 |
2015年 | 37篇 |
2014年 | 53篇 |
2013年 | 123篇 |
2012年 | 44篇 |
2011年 | 67篇 |
2010年 | 31篇 |
2009年 | 36篇 |
2008年 | 24篇 |
2007年 | 25篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1969年 | 1篇 |
1964年 | 1篇 |
1963年 | 2篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有1003条查询结果,搜索用时 0 毫秒
11.
Decisions on selecting an appropriate site for temporary shelter used to be taken in a limited amount of time after a disaster. The need for a systematic method in this area inspired the MADM (multi‐attribute decision making) for complex disaster management decisions. This research proposes a model for appropriate and systematic site selection for temporary shelters, before an earthquake, using a geographical information system and MADM based on an earthquake damage assessment. After the effective criteria for site selection of temporary shelters are determined, the geographical layers of these criteria are prepared for Municipal District No.1 of Greater Tehran, the capital of Iran. Given these attributes and the required shelter area (415–610 hectares), 14 zones are proposed initially. Various MADM methods are used for the final selection. The mean of the aggregated ranking results are determined, and 10 of the 14 initial zones are ranked. 相似文献
12.
The condensation of substituted cinnamaldehydes and arylacetonitriles using sodium ethoxide in ethanol at room temperature afforded 2,5‐diaryl‐2,4‐pentadienenitriles in good yield. The structure of the reaction products was established on the basis of their infrared, nuclear magnetic resonance and elemental analysis data. Two representative compounds were studied for their mutagenic activity. One of them showed a weak mutagenicity while the second showed a high mutagenic activity in TA97a Salmonella strain. Both were negative in TA100. Some of these pentadienenitriles showed fluorescence in solutions. 相似文献
13.
The Gulf of Aqaba exhibits a strong seasonality due to convective mixing during winter and stratification during summer. The present study provides a detailed appraisal of summer and winter sea-water characteristics at the northern coast of the Gulf of Aqaba, that is witnessing rapid development and increasing changes in its geomorphological characteristics. Sea-water temperature, salinity, nutrients, and chlorophyll a concentrations were measured biweekly at five coastal and four cross-sectional stations during the periods February to April and July to September 2004. Meteorological conditions were continuously recorded at the Marine Science Station. The coastal study sites included four open coastal stations and a marina with one-way exchange with the open water. The effect of convective mixing was clearly apparent on the sea-water characteristics. Natural seasonal characteristics of higher nutrients and chlorophyll a concentrations were recorded during winter at most of the open coastal stations. In the cross-sectional stations, the concentrations of nutrients and chlorophyll a were not different between the surface and the bottom during winter, but the bottom waters had generally higher concentrations during summer. Some deviations from the natural seasonal cycle were recorded at the marina and other coastal stations. Here, higher nutrient and chlorophyll a concentrations were recorded in summer than in winter. These deviations that are most likely due to anthropogenic effects are discussed. 相似文献
14.
Mohammad Fareed Manoj Kumar Pathak Vipin Bihari Mohana Krishna Reddy Mudiam Devendra Kumar Patel Neeraj Mathur 《毒物与环境化学》2013,95(10):1919-1928
The aim of this study was to examine the hematological and cholinesterase (ChE) activity levels of pesticide sprayers employed in mango plantations at Lucknow. Fifty-two sprayers from mango plantations who regularly spray mixtures of pesticides including organochlorines (OC), organophosphates (OP), and carbamates were included as exposed group. Twenty residents living close to mango plantations, but not involved in pesticide spraying were taken as controls. Pesticide residues for OC were analyzed in blood by gas chromatography with electron capture detector. There was a significant decrease in acetylcholinesterase and butyrylcholinesterase activities in pesticide sprayers (n?=?52) relative to the control group (n?=?20). A significant difference in the frequency distribution of hematological variations in red blood cell, white blood cell, monocytes, neutrophils, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and platelet count was observed. Residues of OC pesticides including α-hexachlorocyclohexane (HCH) and total HCH were found to be significantly higher in the blood of sprayers compared to controls. Hematological variations were quantitatively more frequent among the sprayers with 5 years of pesticide exposure compared to the controls and to subjects with less than 5 years of exposure group. Hematological abnormalities in sprayers were correlated with pesticide exposure as evidenced by lower ChE activity as well as the presence of OC pesticides in blood. The poorly controlled use of pesticides in the plantation appeared to have produced sub-clinical intoxication in the sprayers and indicated the need for training and implementation of proper, safer hygiene practices. 相似文献
15.
A heteropolyacid Zr(IV) tungstate-based cation exchanger has been synthesized. An amorphous sample, prepared at pH 1.2 and having a Na+ ion exchange capacity of 0.92?meq?g?1, was selected for further studies. Its physicochemical properties were determined using Fourier transform infrared spectrometer, X-ray diffraction, thermogravimetric, and scanning electron studies. To understand the cation exchange behavior of the material, distribution coefficients (K d) for metal ions in various solvent systems were determined. Some important binary separations of metal ions, namely Mg2+–Bi3+, Cd2+–Bi3+, Fe3+–Bi3+, Th4+–Bi3+, and Fe3+–Zn2+, were achieved on such columns. The practical utility of these separations was demonstrated by separating Fe3+ and Zn2+ ions quantitatively in commercial pharmaceutical formulation. The cation exchanger has been successfully applied also for the treatment of industrial wastewater and a synthetic mixture. All the results suggests that Zr(IV) tungstate has excellent potential for the removal of metals from aqueous systems using packed columns of this material. 相似文献
16.
Seidi Farzad Arabi Shamsabadi Ahmad Ebadi Amooghin Abtin Saeb Mohammad Reza Xiao Huining Jin Yongcan Rezakazemi Mashallah 《Environmental Chemistry Letters》2022,20(2):1083-1128
Environmental Chemistry Letters - The application of natural biopolymers such as polysaccharides for the fabrication of bio-based membranes has recently attracted attention for CO2... 相似文献
17.
Utility of North Atlantic Right Whale Museum Specimens for Assessing Changes in Genetic Diversity 总被引:2,自引:0,他引:2
Howard C. Rosenbaum †§§ Mary G. Egan Phillip J. Clapham ‡ Robert L. Brownell JR. § Sobia Malik Moira W. Brown ††‡‡ Bradley N. White Peter Walsh † and Rob Desalle 《Conservation biology》2000,14(6):1837-1842
Abstract: We examined six historical specimens of the endangered North Atlantic right whale ( Eubalaena glacialis ) using DNA isolated from documented baleen plates from the late nineteenth and early twentieth centuries. Sequences from the mitochondrial DNA (mtDNA) control region from these samples were compared with those from a near-exhaustive survey (269 of approximately 320 individuals) of the remaining right whales in the western North Atlantic Ocean. Our results suggest that there has been only relatively modest change in maternal lineage diversity over the past century in the North Atlantic right whale population. Any significant reduction in genetic variation in the species most likely occurred prior to the late nineteenth century. One historical specimen was from the last documented female capable of propagating one of the maternal lineages in the population today; no females in the existing population have been found to carry this mtDNA haplotype. Analysis of the only specimens from the eastern North Atlantic right whale population ever to be examined revealed that eastern and western North Atlantic right whales may not have been genetically differentiated populations. Loss of gene diversity experienced by North Atlantic right whales over the last century has been modest, and the six decades of protection have been successful in maintaining much of the maternal lineage diversity that was present in the late nineteenth century. 相似文献
18.
19.
The purpose of this review is to describe the various aspects of pressure-sensitive adhesives prepared from natural rubber.
Pressure-sensitive adhesives (PSAs) adhere instantaneously to a variety of surfaces upon application of slight pressure and
can be obtained using different technologies. PSAs are materials that develop tack for low pressures and short contact times.
There are number of factors affecting the adhesion property of natural rubber based pressure-sensitive adhesives. In this
review, factors affecting adhesion property such as tack, peel and shear are examined in light of their relevance to adhesion
in addition to measurement methods of each of the three major adhesion properties. This review paper covers the work being
carried out from the last 20 years in the field of natural rubber based pressure sensitive adhesives. 相似文献
20.
Fenton process, as a pretreatment method, was found to be effective in the primary treatment of mature/medium landfill leachate. However, the main problem of the process is the large amount of produced sludge that requires an accurate feasibility evaluation for operational applications. In this study, the response surface methodology was applied for the modeling and optimization of Fenton process in three target responses, (1) overall COD removal, (2) sludge to iron ratio (SIR) and (3) organics removal to sludge ratio (ORSR), where the latter two were new self-defined responses for prediction of sludge generation and applicability assessment of the process, respectively. The effective variables included the initial pH, [H2O2]/[Fe2+] ratio and Fe2+ dosage. According to the statistical analysis, all the proposed models were adequate (with adjusted R2 of 0.9116–0.9512) and had considerable predictive capability (with prediction R2 up to 0.9092 and appropriate adequate precision). It was found that all the variables had significant effects on the responses, specifically by their observed role in dominant oxidation mechanism. The optimum operational conditions obtained by overlay plot, were found to be initial pH of 5.7, [H2O2]/[Fe2+] ratio of 17.72 and [Fe2+] of 195 mM, which led to 69% COD removal, 2.4 (l sludge/consumed mole Fe2+) of SIR and 16.5 (gCOD removed/l produced sludge) for ORSR in verification test, in accordance with models-predicted values. Finally, it was observed that [H2O2]/[Fe2+] ratio and Fe2+ dosage had significant influence on COD removal, while Fe2+ dosage and [H2O2]/[Fe2+] ratio had remarkable effects on SIR and ORSR responses, respectively. 相似文献