全文获取类型
收费全文 | 6006篇 |
免费 | 54篇 |
国内免费 | 39篇 |
专业分类
安全科学 | 248篇 |
废物处理 | 390篇 |
环保管理 | 431篇 |
综合类 | 951篇 |
基础理论 | 1142篇 |
环境理论 | 4篇 |
污染及防治 | 1990篇 |
评价与监测 | 554篇 |
社会与环境 | 369篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 70篇 |
2022年 | 183篇 |
2021年 | 189篇 |
2020年 | 81篇 |
2019年 | 83篇 |
2018年 | 224篇 |
2017年 | 180篇 |
2016年 | 300篇 |
2015年 | 167篇 |
2014年 | 315篇 |
2013年 | 568篇 |
2012年 | 371篇 |
2011年 | 400篇 |
2010年 | 326篇 |
2009年 | 279篇 |
2008年 | 365篇 |
2007年 | 322篇 |
2006年 | 310篇 |
2005年 | 225篇 |
2004年 | 182篇 |
2003年 | 143篇 |
2002年 | 123篇 |
2001年 | 76篇 |
2000年 | 53篇 |
1999年 | 60篇 |
1998年 | 24篇 |
1997年 | 19篇 |
1996年 | 15篇 |
1995年 | 29篇 |
1994年 | 22篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1985年 | 9篇 |
1966年 | 13篇 |
1965年 | 15篇 |
1964年 | 29篇 |
1963年 | 13篇 |
1962年 | 19篇 |
1961年 | 13篇 |
1960年 | 11篇 |
1959年 | 28篇 |
1958年 | 26篇 |
1957年 | 17篇 |
1956年 | 14篇 |
1955年 | 18篇 |
1954年 | 7篇 |
排序方式: 共有6099条查询结果,搜索用时 15 毫秒
11.
Francisco M. Baena-Moreno Mónica Rodríguez-Galán Fernando Vega Luis F. Vilches Benito Navarrete 《International Journal of Green Energy》2019,16(5):401-412
Biomethane production through biogas upgrading is a promising renewable energy for some industries which could be part of the equilibrium needed with fossil fuels consumption to achieve a sustainable society. This paper presents a comprehensive list of biogas upgrading technologies focused on carbon dioxide removal as well as recent advances reported by researcher with wide expertise in this topic. Additionally, an extensive costs–performance comparison among the technologies studied is discussed. Among the different alternatives, chemical scrubbing stood out to achieve high biomethane purities while cryogenic technologies proved to be effective against methane losses. Regarding the different costs, water scrubbing and membrane separation seem to be the most affordable techniques. 相似文献
12.
Goettems-Fiorin Pauline Brendler Costa-Beber Lilian Corrêa dos Santos Jaíne Borges Friske Paula Taís Sulzbacher Lucas Machado Frizzo Matias Nunes Ludwig Mirna Stela Rhoden Cláudia Ramos Heck Thiago Gomes 《Environmental science and pollution research international》2019,26(20):20581-20594
Environmental Science and Pollution Research - The reduction of estrogen levels, as a result of menopause, is associated with the development of metabolic diseases caused by alterations in... 相似文献
13.
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
14.
15.
Almeida CA Quintar S González P Mallea MA 《Environmental monitoring and assessment》2007,133(1-3):459-465
A study of the water quality of the Potrero de los Funes River (San Luis – Argentina) was carried out in order to evaluate
the possible effect of the anthropogenic activities on the river developed in the homonymous town. Samples were collected
during the period March 2000–November 2005 at three selected sampling sites (RP1, RP2 and RP3). Different physicochemical and bacteriological parameters (turbidity, pH, conductivity, suspended solids, alkalinity, potassium,
sodium, calcium, magnesium, chlorides, nitrates, phosphates, sulphates, chemical oxygen demand (COD), 5-day biological oxygen
demand (BOD5), dissolved oxygen, total coliforms, Escherichia coli and total heterotrophic bacteria) were analysed according to the Standard Method for the Examination of Water and Wastewater.
When comparing the values of total coliforms, E. coli, total heterotrophic bacteria, COD, BOD5 and phosphates from the zone without anthropogenic influence (RP1) and the urban zones (RP2 and RP3) an important variation in the parameters was observed. These results indicate that the urban activity produces a serious
and negative effect on the water quality, thus constituting a sanitary risk and may have a major impact on the trophic status
of the Potrero de los Funes dam. As case study, we report on the use of General Quality Index (GQI) to evaluate spatial and
seasonal changes in the water quality of Potrero de los Funes River. Results revealed a significant degradation of the water
quality at RP2 and RP3. 相似文献
16.
17.
Matthew Bates Paolo Bruno Mariangela Caputi Maurizio Caselli Gianluigi de Gennaro Maria Tutino 《Atmospheric environment (Oxford, England : 1994)》2008,42(24):6144-6151
The technique of thermal desorption (TD)–GC/MS was evaluated for measuring airborne, 4–6 ring polycyclic aromatic hydrocarbons (PAHs) collected onto quartz filters. TD provides a more readily automated and sensitive alternative to traditional solvent extraction, decreasing the time/cost of analysis and reducing the risk of analyte loss or sample contamination. The developed method was successfully applied to the analysis of PAH standard solutions loaded on sorbent tubes packed with quartz wool and the graphitized carbon black sorbent Carbograph2. The optimized method showed high desorption efficiency over the whole range of target PAHs with good precision, linearity and sensitivity. The proposed method was verified on an urban dust Standard Reference Material (SRM 1649a); the experimentally determined concentrations agreed with the certified ranges (95% confidence limit) for all target compounds except benzo[a]anthracene, which fell just outside the narrow certified range. The desorption efficiency and the reproducibility of the method was evaluated by analysing pieces of real sample filters sampled from urban air for a period of 24 h. The results confirmed the homogeneity of the filter and showed high recovery efficiencies for all target PAHs. 相似文献
18.
Dario Paladini Maria Giovanna Russo Antonio Tartaglione Annamaria Loffredo Pasquale Martinelli 《黑龙江环境通报》2002,22(13):1185-1187
Toriello–Carey syndrome is a rare malformative complex, described for the first time in 1988, characterized by agenesis of the corpus callosum, facial anomalies, cardiac defects and hypotonia. Relatively few neonatal cases have been reported. We describe here the first prenatal ultrasound diagnosis of the syndrome based on the detection of agenesis of the corpus callosum and spongious cardiomyopathy in a 22-week-old fetus of a couple with positive family history. The first sib of the couple was diagnosed with Toriello–Carey syndrome at 1 year of age, and had, in addition to the typical facial anomalies not detectable by ultrasound, agenesis of the corpus callosum and the same heart lesion (spongious cardiomyopathy). This report demonstrates that prenatal diagnosis of Toriello–Carey syndrome is feasible in the second trimester of pregnancy. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
19.
The structure of the choroid plexus was studied in five normal human embryos, three normal fetuses and three fetuses with choroid plexus cysts. These were detected by ultrasound and the fetuses were karyotypically normal. The choroid plexus appears in the lateral cerebral ventricles at the seventh developmental week. The early structure is lobulated with vessels running in the mesenchymal stroma and forming capillary nets under the single-layered ependymal epithelium. This embryonal structure is converted into the fetal type during the ninth developmental week as the embryonal capillary net is replaced by elongated loops of wavy capillaries that lie under regular longitudinal epithelial folds. The choroid plexus cysts exhibited accumulation of fluid within distended mesenchymal stroma and did not show the wavy folds on this surface, which was smooth. Within this connective tissue of the cyst wall were distended angiomatous interconnecting thin-walled capillaries. Therefore, filled cavities were not lined by any epithelium. We suggest that fetal choroid plexuses cysts (at least in many cases) are in fact pseudocysts exhibiting angiomatous patterns of capillaries in their walls. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
20.
To prevent acid mine drainage arising from oxygen and water penetration of sulphide-rich mine tailings, the tailings are covered with layers of dry sealing material. Plant roots have a great ability to penetrate dense materials, and if the roots are able to penetrate the sealing layer of a tailings deposit, its oxygen-shielding properties could be reduced. The objective of this study was to evaluate whether plant roots are able to penetrate sealing layers covering mine tailings deposits. Root penetration into layers of various sealing materials, such as clayey moraine (clay, 8-10%; silt, 22-37%; sand, 37-55%; gravel, 15-18%), moraine (unspecified), 6-mm bentonite (kaolin clay) fabric, lime and clay, Cefyll (mixture of pulverized coal fly ash, cement and water) and a mixture containing biosludge (30-35%) and bioashes (65-70%), was investigated. In the field, roots were studied by digging trenches alongside vegetation growing in 3- and 10-year-old mine sites. In the greenhouse root growth of Betula pendula, Pinus sylvestris, Poa pratensis and Salix viminalis were studied in compartments where the plants had been growing for 22 months. The results from the field experiment indicated that roots are able to penetrate both deep down in the cover layer (1.7 m) and also into the sealing layers of various materials, and even to penetrate hard Cefyll. The addition of nutrients in the top cover reduced deep root growth and thereby also penetration through the sealing layer. Low hydraulic conductivity of the sealing layer or a thick cover layer had less effect on root penetration. In the greenhouse experiment roots did not penetrate the thin bentonite fabric, due to low pH (2.1-2.7) that was created from the underlying weathered mine tailings. The clayey moraine was penetrated by all species used in the greenhouse experiment; Pinus sylvestris had the greatest ability to penetrate. To prevent root penetration of the other sealing layer, a suitable condition for the plants should be created in the upper part of the cover layer, namely a sufficient amount of plant nutrients. However, to define such a condition is difficult since different plant species have different requirements. 相似文献