全文获取类型
收费全文 | 1260篇 |
免费 | 14篇 |
国内免费 | 34篇 |
专业分类
安全科学 | 17篇 |
废物处理 | 62篇 |
环保管理 | 173篇 |
综合类 | 114篇 |
基础理论 | 211篇 |
污染及防治 | 436篇 |
评价与监测 | 224篇 |
社会与环境 | 68篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 38篇 |
2022年 | 82篇 |
2021年 | 69篇 |
2020年 | 13篇 |
2019年 | 26篇 |
2018年 | 41篇 |
2017年 | 41篇 |
2016年 | 59篇 |
2015年 | 27篇 |
2014年 | 54篇 |
2013年 | 152篇 |
2012年 | 60篇 |
2011年 | 74篇 |
2010年 | 57篇 |
2009年 | 52篇 |
2008年 | 73篇 |
2007年 | 51篇 |
2006年 | 46篇 |
2005年 | 39篇 |
2004年 | 34篇 |
2003年 | 29篇 |
2002年 | 22篇 |
2001年 | 17篇 |
2000年 | 9篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1978年 | 4篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1972年 | 3篇 |
1969年 | 6篇 |
1968年 | 4篇 |
1965年 | 2篇 |
1959年 | 2篇 |
1957年 | 3篇 |
1956年 | 2篇 |
排序方式: 共有1308条查询结果,搜索用时 15 毫秒
951.
Gopal Datt Bhatta Hemant Raj Ojha Pramod Kumar Aggarwal V. Rasheed Sulaiman Parvin Sultana Dhanej Thapa Nimisha Mittal Khemraj Dahal Paul Thomson Laxman Ghimire 《Environment, Development and Sustainability》2017,19(2):497-525
While impacts of climate change on agricultural systems have been widely researched, there is still limited understanding of what agricultural innovations have evolved over time in response to both climatic and non-climatic drivers. Although there has been some progress in formulating national adaptation policies and strategic planning in different countries of South Asia, research to identify local-level adaptive strategies and practices is still limited. Through eight case studies and a survey of 300 households in 15 locations in India, Nepal and Bangladesh, this paper generates empirical evidence on emerging agricultural innovations in contrasting socio-economic, geographical and agro-ecological contexts. The study demonstrates that several farm practices (innovations) have emerged in response to multiple drivers over time, with various forms of institutional and policy support, including incentives to reduce risks in the adoption of innovative practice. It further shows that there is still limited attempt to systematically mainstream adaptation innovations into local, regional and national government structures, policies and planning processes. The paper shows that the process of farm-level adaptation through innovation adoption forms an important avenue for agricultural adaptation in South Asia. A key implication of this finding is that there is a need for stronger collaborations between research institutions, extension systems, civil society and the private sector actors to enhance emerging adaptive innovations at the farm level. 相似文献
952.
A series of oxime esters was synthesized by esterification of 3-ethoxy-4-benzaldehyde oxime with acid chlorides in the presence of triethylamine. They were evaluated for their in vitro antifungal activity against three pathogenic fungi, namely Rhizoctonia bataticola, Fusarium udum, and Alternaria porii, and their antibacterial activity against the three bacterial strains Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoneae. The compounds bearing medium-length alkyl chains showed greater activity than those with long alkyl chains. An electron-donating group in para position of the aryl ring confers highest activity. 相似文献
953.
Namita Ashish Singh 《Environmental Chemistry Letters》2017,15(2):185-191
Nanotechnology can be defined as the use of nanomaterials for human benefit. Nanomaterials have unique properties due to their physical and chemical characteristics at the nanoscale (10?9 nm). Nowadays, nanotechnology is providing new products in all industrial sectors. This article reviews innovations in fields such as biomedical, diagnosis of diseases, therapeutics, agriculture and food, nanofertilizers, oil, gas, textile and cosmeceuticals and packaging. Recent trends of patents and scholarly publications in nanotechnology are also discussed. 相似文献
954.
Sundar Raj Chockalingam Micheal Kumar Peniel Pauldoss 《International Journal of Green Energy》2017,14(12):1027-1033
This work aimed to prove the effects of adding different proportions of ethanol with diesel (DE) and ethanol–water mixture with diesel (DEW) in a single-cylinder diesel engine on the performance, emissions, and combustion parameters. The blends were stabilized by tetra methyl ammonium bromide (TMAB) as the additive. The study was conducted at two operating conditions initially on a normal diesel engine and in the second case the engine piston, valves, and cylinder head coated with zirconia (ZrO2) alumina (Al2O3). The results showed that the addition of 10% ethanol with diesel performed almost equivalent to neat diesel with 29.2% BTE and a 17.7% decrease in smoke and an 11.4% increase in NOx emission at peak load compared to that of the base fuel. Modified engines with thermal barrier coating (TBC) performed superior to normal engines with 4% and 5.5% increase in BTE, respectively, for DE- and DEW-type fuels with reduced exhaust emissions. A 5% addition of water with diesel–ethanol blends favors a higher proportion of ethanol to be employed in diesel engines. 相似文献
955.
Dipnarayan Ganguly Gurmeet Singh Purvaja Ramachandran Arumughan Paneer Selvam Kakolee Banerjee Ramesh Ramachandran 《Ambio》2017,46(6):667-679
Net ecosystem metabolism and subsequent changes in environmental variables were studied seasonally in the seagrass-dominated Palk Bay, located along the southeast coast of India. The results showed that although the water column was typically net heterotrophic, the ecosystem as a whole displayed autotrophic characteristics. The mean net community production from the seagrass meadows was 99.31 ± 45.13 mM C m?2 d?1, while the P/R ratio varied between 1.49 and 1.56. Oxygen produced through in situ photosynthesis, exhibited higher dependence over dissolved CO2 and available light. Apportionment of carbon stores in biomass indicated that nearly three-fourths were available belowground compared to aboveground. However, the sediment horizon accumulated nearly 40 times more carbon than live biomass. The carbon storage capacities of the sediments and seagrass biomass were comparable with the global mean for seagrass meadows. The results of this study highlight the major role of seagrass meadows in modification of seawater chemistry. Though the seagrass meadows of Palk Bay are increasingly subject to human impacts, with coupled regulatory and management efforts focused on improved water quality and habitat conservation, these key coastal ecosystems will continue to be valuable for climate change mitigation, considering their vital role in C dynamics and interactions with the overlying water column. 相似文献
956.
Kumar Neeraj Krishnani Kishore Kumar Singh Narendra Pratap 《Environmental science and pollution research international》2017,24(19):16137-16147
Environmental Science and Pollution Research - The concentrations of 14 metals, namely, chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se), arsenic (As),... 相似文献
957.
Singh Shatrughan Dash Padmanava Silwal Saurav Feng Gary Adeli Ardeshir Moorhead Robert J. 《Environmental science and pollution research international》2017,24(16):14124-14141
Environmental Science and Pollution Research - Water quality of lakes, estuaries, and coastal areas serves as an indicator of the overall health of aquatic ecosystems as well as the health of the... 相似文献
958.
Ganesh Raj Ghimire Witold F. Krajewski 《Journal of the American Water Resources Association》2020,56(3):542-550
In this study, the authors explore three persistence approaches in streamflow forecasting motivated by the need for forecasting model skill evaluation. The authors use streamflow observations with 15 min resolution from the year 2008 to 2017 at 140 United States Geological Survey streamflow gauges monitoring the streams and rivers over the State of Iowa. The spatial scale of the basins ranges from about 7 to 37,000 km2. The study explores three approaches: simple persistence, gradient persistence, and anomaly persistence. The study shows that persistence forecasts skill has strong dependence on basin scales and weaker but non‐negligible dependence on geometric properties of the river network for a given basin. Among the three approaches explored, anomaly persistence shows highest skill especially for small basins, under about 500 km2. The anomaly persistence can serve as a benchmark for model evaluations considering the effect of basin scales and geometric properties of river network of the basin. This study further reiterates that persistence forecasts are hard‐to‐beat methods for larger basin scales at short to medium forecast range. 相似文献
959.
Jaspreet Kaur Ravinder Singh Sawhney Maninder Singh 《International Journal of Green Energy》2020,17(5):309-318
ABSTRACTIn the era of developing technologies, there is always been a crisis of rising demands of energy. There is no skepticism that a lot of energy is being produced every hour for almost each and every field, but still an exploration is needed to come up with new and viable options for energy creation. The same is the objective of this paper which proposes the use of waste biomaterials in association with organic and inorganic materials as a source of energy to power up small electronic devices. In this research egg shell membrane (ESM)-based triboelectric nanogenerator (TENG) is proposed in combination with calotropis (Calo), cellulose from fruit of Bombax Ceiba (BOM), cellulose in form of tissue paper (TISU), dog hair (DH), polytetrafluoroethylene (PTFE), aluminum (Al), and copper (Cu). ESM is eco-friendly waste food by-product and available in abundance. Characterization of ESM is done by scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectrophotometer (FTIR). The proposed ESM-PTFE-based TENG power up 462 green LEDs (462 × 2 V = 924 V ~ 1 kV) without rectifier and produced up to 7.61 µJ energy with 4.7 µF capacitor at 200 tapings. All the proposed ESM-based TENG combinations generate sufficient voltage to turn ON the wrist watch. This green-energy-based TENG has potential application in various fields especially related to medical devices. 相似文献
960.
A. Pratheep Kumar Jitendra K. Pandey Bijendra Kumar R. P. Singh 《Journal of Polymers and the Environment》2006,14(2):203-212
Composites were prepared by two methods, (i) graft copolymerization (GFC) of isotactic polypropylene (PP) with maliec anhydride, (MAH) followed by esterification with coir fiber and (ii) by direct reactive mixing (DFC) of polypropylene (PP) and ethylene–propylene (EP) copolymers with MAH and peroxide with coir fiber. These composites, after molding in films (5×5 cm,
m thickness) were examined for susceptibility to biological attack by measuring the percentage weight loss in compost upto 6 months, periodically, and fungal colonization on surface of the samples, when kept as sole carbon source for the growth of Aspergillus niger in culture medium upto 40 days. Photodegradation was evaluated by monitoring the variations in FT-IR spectrum and crack formation after successive treatment with UV light (≥290 nm) for 0, 20, 50 and 100 h at 60°C in the presence of air. Specimens of virgin PP were taken as a reference during all period of photo and biodegradation studies. Significant changes were observed depending on the preparation methods during photodegradation and biodisintegration of composites. DFCs samples were disintegrated faster than GFCs during the composting whereas, in culture, GFCs were covered highly in well uniform way by fungi. It was observed that photo-oxidative ageing directly enhanced the biodegradability of composites as the increase in fungal growth rate and decrease in weight during composting were found. It was concluded that extent of compatibilization had a profound effect on photo-oxidation and biodisintegration of composite material; consequently ester bonds were main units during fungal consumption. Composition of monomers in copolymers was also showing significant effect on the degradability which decreased with increasing content of ethylene in ethylene–propylene (EP) copolymers. 相似文献