全文获取类型
收费全文 | 4121篇 |
免费 | 38篇 |
国内免费 | 16篇 |
专业分类
安全科学 | 89篇 |
废物处理 | 255篇 |
环保管理 | 298篇 |
综合类 | 584篇 |
基础理论 | 838篇 |
环境理论 | 7篇 |
污染及防治 | 1453篇 |
评价与监测 | 370篇 |
社会与环境 | 271篇 |
灾害及防治 | 10篇 |
出版年
2023年 | 49篇 |
2022年 | 109篇 |
2021年 | 159篇 |
2020年 | 64篇 |
2019年 | 67篇 |
2018年 | 159篇 |
2017年 | 149篇 |
2016年 | 215篇 |
2015年 | 132篇 |
2014年 | 243篇 |
2013年 | 384篇 |
2012年 | 279篇 |
2011年 | 283篇 |
2010年 | 219篇 |
2009年 | 142篇 |
2008年 | 222篇 |
2007年 | 256篇 |
2006年 | 188篇 |
2005年 | 158篇 |
2004年 | 115篇 |
2003年 | 97篇 |
2002年 | 91篇 |
2001年 | 49篇 |
2000年 | 42篇 |
1999年 | 24篇 |
1998年 | 18篇 |
1997年 | 13篇 |
1996年 | 10篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1988年 | 5篇 |
1980年 | 5篇 |
1970年 | 7篇 |
1967年 | 6篇 |
1966年 | 8篇 |
1965年 | 7篇 |
1964年 | 17篇 |
1963年 | 7篇 |
1962年 | 5篇 |
1961年 | 9篇 |
1960年 | 10篇 |
1959年 | 9篇 |
1958年 | 22篇 |
1957年 | 10篇 |
1956年 | 6篇 |
1955年 | 5篇 |
排序方式: 共有4175条查询结果,搜索用时 187 毫秒
231.
António A. Martins Marta Simaria Joaquim Barbosa Ricardo Barbosa Daniela T. Silva Cristina S. Rocha Teresa M. Mata Nídia S. Caetano 《Environment, Development and Sustainability》2018,20(1):129-153
This paper investigates multi-stakeholder arrangements initiated by businesses and NGOs from the North that aim to enhance a more sustainable agricultural production at specific localities in Southern countries. We aim to better understand the search for concerted action in multi-actor arrangements. Therefore, this paper presents a diagnostic framework with three strategic challenges the partnership projects are facing: linking global economic objectives to local needs, values and interests; bridging public and private interests and responsibilities; and seeking trade-offs between social, environmental and economic values. Starting from the partnerships’ Theory of Change, this diagnostic framework is applied to comparative case studies of partnership projects in the cocoa sector in Indonesia, which are part of a Northern-based public–private partnership to improve farmers’ prospective. It is concluded that the economic reality faced by the farmers differs from that of the Northern actors; collaboration with governments is difficult because of different organizational cultures; and the partnership projects underestimate the strength of vested social relations the smallholders are part of. Overall, the initiators of the partnerships seem to work with a too restricted economic interpretation of the local reality. 相似文献
232.
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
233.
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
234.
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
235.
Patricia Blanco-Piñeiro M. Pino Díaz-Pereira Aurora Martínez Vidal 《International journal of occupational safety and ergonomics》2018,24(2):316-323
Objective. Bad posture increases the risk that a musician may suffer from musculoskeletal disorders. This study compared posture quality required by different instruments or families of instruments. Methods. Using an ad-hoc postural observation instrument embracing 11 postural variables, four experts evaluated the postures of 100 students attending a Spanish higher conservatory of music. Results. The agreement of the experts’ evaluations was statistically confirmed by a Cohen's κ value between 0.855 and 1.000 and a Kendall value between 0.709 and 1.000 (p?0.001 in all cases). Moreover, χ2 tests revealed significant association between instrument families and seated posture with respect to pelvic attitude, dorsal curvature and head alignment in both sagittal and frontal planes. This analysis also showed an association between instrument families and standing posture with respect to the frontal plane of the axis of gravity, pelvic attitude, head alignment in the frontal plane, the sagittal plane of the shoulders and overall posture. Conclusions. While certain postural defects appear to be common to all families of instruments, others are more characteristic of some families than others. The instrument associated with the best posture quality was the bagpipe, followed by percussion and strings. 相似文献
236.
Benito-Garzón Marta Fady Bruno Davi Hendrik Vizcaíno-Palomar Natalia Fernández-Manjarrés Juan 《Regional Environmental Change》2018,18(5):1427-1437
Regional Environmental Change - The adaptation of social-ecological systems such as managed forests depends largely on decisions taken by forest managers who must choose among a wide range of... 相似文献
237.
Regional Environmental Change - This article presents an energy analysis of Quebec agroecoystems at five periods of time: 1871, 1931, 1951, 1981, and 2011, calculating for each year the various... 相似文献
238.
Nogueira Euler Melo Yanai Aurora Miho de Vasconcelos Sumaia Saldanha de Alencastro Graça Paulo Maurício Lima Fearnside Philip Martin 《Regional Environmental Change》2018,18(1):261-270
Regional Environmental Change - By 2014 approximately 2.2 million km2 (~43%) of Brazil’s Legal Amazonia region had been incorporated into an extensive network of 718 protected areas, which... 相似文献
239.
Jérémy Bonvoisin 《International Journal of Sustainable Engineering》2017,10(4-5):198-206
AbstractIn pursuit of coping mechanisms for the challenges of sustainable manufacturing, systematic methods have been developed to allow engineers to improve the ratio between products’ utility and environmental impact. These necessary efforts remain however limited if the surrounding production and consumption practices are not called into question at the same time. This article introduces open source product development as a potential approach for unlocking the limits of existing sustainable product design practices and to lead towards alternative and eco-efficient production and consumption practices termed as participative production. First, it discusses the potential advantages of this emerging practice in terms of environmental sustainability. Second, it provides a screened qualitative environmental analysis of 18 exemplary open source hardware products. Specific sustainable design principles implemented by these products are highlighted and discussed in order to identify challenges for further common research in the field of open source and sustainable product development. 相似文献
240.
Nearest neighbor (NN) methods are widely employed for drawing inferences about spatial point patterns of two or more classes. We introduce a method for testing reflexivity in the NN structure (i.e., NN reflexivity) based on a contingency table which will be called reflexivity contingency table (RCT) henceforth. The RCT is based on the NN relationships among the data points and was used for testing niche specificity in literature, but we demonstrate that it is actually more appropriate for testing the NN reflexivity pattern. We derive the asymptotic distribution of the entries of the RCT under random labeling and introduce tests of reflexivity based on these entries. We also consider Pielou’s approach on RCT and show that it is not appropriate for completely mapped spatial data. We determine the appropriate null hypotheses and the underlying conditions/assumptions required for all tests considered. We investigate the finite sample performance of the tests in terms of empirical size and power by extensive Monte Carlo simulations and illustrate the methods on two real-life ecological data sets. 相似文献