全文获取类型
收费全文 | 7055篇 |
免费 | 65篇 |
国内免费 | 35篇 |
专业分类
安全科学 | 128篇 |
废物处理 | 432篇 |
环保管理 | 540篇 |
综合类 | 1033篇 |
基础理论 | 1443篇 |
环境理论 | 10篇 |
污染及防治 | 2484篇 |
评价与监测 | 622篇 |
社会与环境 | 435篇 |
灾害及防治 | 28篇 |
出版年
2023年 | 83篇 |
2022年 | 190篇 |
2021年 | 249篇 |
2020年 | 109篇 |
2019年 | 102篇 |
2018年 | 257篇 |
2017年 | 238篇 |
2016年 | 363篇 |
2015年 | 201篇 |
2014年 | 402篇 |
2013年 | 647篇 |
2012年 | 449篇 |
2011年 | 461篇 |
2010年 | 350篇 |
2009年 | 259篇 |
2008年 | 422篇 |
2007年 | 434篇 |
2006年 | 366篇 |
2005年 | 266篇 |
2004年 | 215篇 |
2003年 | 174篇 |
2002年 | 161篇 |
2001年 | 93篇 |
2000年 | 75篇 |
1999年 | 52篇 |
1998年 | 26篇 |
1997年 | 26篇 |
1996年 | 17篇 |
1995年 | 39篇 |
1994年 | 24篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 15篇 |
1989年 | 11篇 |
1985年 | 7篇 |
1967年 | 9篇 |
1966年 | 14篇 |
1965年 | 16篇 |
1964年 | 31篇 |
1963年 | 12篇 |
1962年 | 17篇 |
1961年 | 11篇 |
1960年 | 10篇 |
1959年 | 28篇 |
1958年 | 37篇 |
1957年 | 20篇 |
1956年 | 14篇 |
1955年 | 19篇 |
1954年 | 9篇 |
排序方式: 共有7155条查询结果,搜索用时 250 毫秒
241.
The manufacturing industry produces a lot of different by-products and waste. In this research, the utilization of different industrial wastes as a part of wood-plastic composites was tested. Limestone waste and carton cutting waste were tested by replacing part of the reinforcing fibers of the composite with these materials. The materials were made with the extrusion process, and they were tested for their mechanical properties, water absorption and thickness swelling. The materials were also viewed with a scanning electron microscope. The results showed that both industrial wastes affected the properties of the composite. Mining waste in the composite improved the moisture properties, impact strength and hardness of the material. Carton cutting waste improved the impact strength remarkably. 相似文献
242.
Larissa Stieven Montagna Thaís Larissa do Amaral Montanheiro Fábio Roberto Passador Ana Paula Lemes Mirabel Cerqueira Rezende 《Journal of Polymers and the Environment》2018,26(4):1511-1519
The potential use of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/graphite nanosheets (GNS) as a biodegradable nanocomposite has been explored. PHBV/GNS nanocomposites films were prepared by solution casting at various concentrations of GNS—0.25, 0.50 and 1.00 wt% GNS. The films were exposed to artificial ultraviolet radiation (UV) during 52 h. The effect of GNS on PHBV photodegradation was investigated and compared to neat PHBV film. The artificial photodegradation induced changes in physical (weight loss), chemical carbonyl index by Fourier transform infrared spectroscopy, thermal degree of crystallinity and melting temperature by differential scanning calorimetry and morphological scanning electron microscopy characteristics. Based on the results obtained from aforementioned analyzes it was verified that GNS inhibits the oxidative degradation of PHBV matrix. 相似文献
243.
Markéta Julinová Roman Slavík Martina Vyoralová Alena Kalendová Pavol Alexy 《Journal of Polymers and the Environment》2018,26(4):1459-1472
The demand for biodegradable plastic material is increasing worldwide. However, the cost remains high in comparison with common forms of plastic. Requirements comprise low cost, good UV-stability and mechanical properties, as well as solubility and water uptake lead to the preparation of multi-component polymer blends based on polyvinyl alcohol and starch in combination with waste products that are hard to utilize—waste lignin and hydrolysate extracted from chromium tanned waste. Surprisingly the addition of such waste products into PVA gives rise to blends with better biodegradability than commercial PVA in an aquatic aerobic environment with non-adapted activated sludge. These blends also exhibited greater solubility in the water and UV stability than commercial PVA. Tests on the processing properties of the blends (melt flow index, tensile strength and elongation at break of the films) as well as their mechanical properties showed that materials based on these blends might be applied in agriculture (for example as the systems for controlled-release pesticide or fertilizer) and, somewhat, in the packaging sector. 相似文献
244.
Baked Foams Based on Cassava Starch Coated with Polyvinyl Alcohol with a Higher Degree of Hydrolysis
Fabíola Azanha de Carvalho Ana Paula Bilck Fabio Yamashita Suzana Mali 《Journal of Polymers and the Environment》2018,26(4):1445-1452
The aims of this work were to produce trays based on cassava starch, coated with polyvinyl alcohol (PVA) with a higher degree of hydrolysis (98%), and to study the effects of the coating on the mechanical and water sorption properties of the trays. Two types of PVA were tested: SELVOL? 325 (degree of polymerization?=?1000–1500) and SELVOL? 107 (degree of polymerization?=?350–650). A decrease in the water absorption capacity of 50% was observed when the coated samples were compared with the control sample after 30 min of immersion in water. It was observed in both coated samples a reduction of the initial rate of water adsorption sorption and a decrease in hydrophilicity compared with the control sample. Tensile strength and elongation were increased with application of the coatings. The use of the two types of PVA resulted in materials with similar mechanical and water sorption properties. 相似文献
245.
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
246.
Anna Zubrowska Ewa Piorkowska Joanna Bojda 《Journal of Polymers and the Environment》2018,26(1):145-151
Blending of polylactide (PLA) with low stereoregularity and polyhedral oligomeric silsesquioxane grafted with arms of poly(ethylene glycol) methyl ether, acting as a plasticizer, allowed us previously to obtain a novel stable elastomeric-like material. The present contribution focuses on the properties of semi-crystalline PLA plasticized with this compound. Melt blends of PLA with 5–15 wt% of the plasticizer, were compression molded, quenched and annealed, which enabled cold-crystallization. The glass transition temperature of the blends and their drawability depended on their crystallinity and plasticizer content. The best ductility was reached at the plasticizer content of 15 wt%; the achieved strain at break was 6.5 (650%) and 1.3 (130%), for the quenched and annealed material, respectively. The latter value exceeded 20 times the strain at break of neat crystalline PLA. The tensile toughness of the annealed 15 wt% blend was 12 times larger than that of crystalline PLA. Moreover, annealing of 15 wt% blend improved its yield strength by 40%. Despite the two peaks of the loss modulus, indicating the two glass transitions in this blend, no heterogeneities were found by scanning electron microscopy, indicating that the plasticizer enriched phase formed instead of distinct inclusions of the plasticizer. 相似文献
247.
Anke Fischer Wouter Spekkink Christine Polzin Alberto Díaz-Ayude Ambra Brizi Irina Macsinga 《环境政策》2018,27(4):621-643
There is a substantial body of literature on public understandings of large-scale ‘environmental’ phenomena such as climate change and resource degradation. At the same time, political science and economics analyse the governance arrangements to deal with such issues. These realms of research rarely meet: there has been little research into people’s understandings of the governance of environmental change. This study adds a psychological perspective to governance research by investigating social representations of governance that promotes societal change towards sustainability, and related practices. It examines data from qualitative interviews with sustainability-interested people in seven European countries (n = 105). The analysis identified building blocks of representations suitable as an analytical framework for future research on governance representations. The diversity of their content reflected a range of pathways to societal change. Representations often seemed to have a creative function as a guiding vision for individuals’ own practices, but their wider transformative potential was constrained. 相似文献
248.
Maartje J. Klapwijk Anna J. M. Hopkins Louise Eriksson Maria Pettersson Martin Schroeder Åke Lindelöw Jonas Rönnberg E. Carina H. Keskitalo Marc Kenis 《Ambio》2016,45(2):223-234
Intensifying global trade will result in increased numbers of plant pest and pathogen species inadvertently being transported along with cargo. This paper examines current mechanisms for prevention and management of potential introductions of forest insect pests and pathogens in the European Union (EU). Current European legislation has not been found sufficient in preventing invasion, establishment and spread of pest and pathogen species within the EU. Costs associated with future invasions are difficult to estimate but past invasions have led to negative economic impacts in the invaded country. The challenge is combining free trade and free movement of products (within the EU) with protection against invasive pests and pathogens. Public awareness may mobilise the public for prevention and detection of potential invasions and, simultaneously, increase support for eradication and control measures. We recommend focus on commodities in addition to pathways, an approach within the EU using a centralised response unit and, critically, to engage the general public in the battle against establishment and spread of these harmful pests and pathogens. 相似文献
249.
250.
Marcela Capcarova Katarina Zbynovska Anna Kalafova Jozef Bulla Peter Bielik 《Journal of environmental science and health. Part. B》2016,51(4):236-244
The contamination of food and feed by mycotoxins as toxic metabolites of fungi is a risk not only for consumers resulting in various embarrassment regarding health status and well-being, but also for producers, companies and export market on the ground of economic losses and ruined stability of economic trade. As it is given in historical evidence, the contamination of food by mycotoxins is a topic as old as a history of mankind, finding some evidence even in the ancient books and records. Nowadays, the mycotoxins are used in modern biotechnological laboratories and are considered an agent for targeting the specific cells (e.g., defected cells to eliminate them). However, this promising procedure is only the beginning. More concern is focused on mycotoxins as abiotic hazard agents. The dealing with them, systematic monitoring, and development of techniques for their elimination from agricultural commodities are worldwide issues concerning all countries. They can be found alone or in co-occurrence with other mycotoxins. Thus, this review aims to provide widened information regarding mycotoxins contamination in environment with the consequences on health of animals and humans. The inevitability for more data that correctly determine the risk points linked to mycotoxins occurrence and their specific reactions in the environment is demonstrated. This review includes various symptoms in animals and humans that result from mycotoxin exposure. For better understanding of mycotoxin's impact on animals, the sensitivities of various animal species to various mycotoxins are listed. Strategies for elimination and preventing the risks of mycotoxins contamination as well as economical approach are discussed. To complete the topic, some data from past as historical evidences are presented. 相似文献