全文获取类型
收费全文 | 39437篇 |
免费 | 409篇 |
国内免费 | 442篇 |
专业分类
安全科学 | 998篇 |
废物处理 | 1972篇 |
环保管理 | 5513篇 |
综合类 | 5839篇 |
基础理论 | 10924篇 |
环境理论 | 11篇 |
污染及防治 | 9531篇 |
评价与监测 | 2761篇 |
社会与环境 | 2523篇 |
灾害及防治 | 216篇 |
出版年
2022年 | 254篇 |
2021年 | 271篇 |
2020年 | 266篇 |
2019年 | 260篇 |
2018年 | 1817篇 |
2017年 | 1715篇 |
2016年 | 1762篇 |
2015年 | 627篇 |
2014年 | 738篇 |
2013年 | 2465篇 |
2012年 | 1366篇 |
2011年 | 2592篇 |
2010年 | 1717篇 |
2009年 | 1674篇 |
2008年 | 2131篇 |
2007年 | 2502篇 |
2006年 | 1256篇 |
2005年 | 1019篇 |
2004年 | 1098篇 |
2003年 | 1046篇 |
2002年 | 1020篇 |
2001年 | 1224篇 |
2000年 | 890篇 |
1999年 | 552篇 |
1998年 | 416篇 |
1997年 | 399篇 |
1996年 | 407篇 |
1995年 | 471篇 |
1994年 | 445篇 |
1993年 | 386篇 |
1992年 | 379篇 |
1991年 | 371篇 |
1990年 | 387篇 |
1989年 | 382篇 |
1988年 | 311篇 |
1987年 | 279篇 |
1986年 | 276篇 |
1985年 | 281篇 |
1984年 | 360篇 |
1983年 | 315篇 |
1982年 | 322篇 |
1981年 | 301篇 |
1980年 | 244篇 |
1979年 | 273篇 |
1978年 | 212篇 |
1977年 | 197篇 |
1975年 | 182篇 |
1974年 | 191篇 |
1973年 | 183篇 |
1972年 | 204篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Jeremy R. Brammer Nicolas D. Brunet A. Cole Burton Alain Cuerrier Finn Danielsen Kanwaljeet Dewan Thora Martina Herrmann Micha V. Jackson Rod Kennett Guillaume Larocque Monica Mulrennan Arun Kumar Pratihast Marie Saint‐Arnaud Colin Scott Murray M. Humphries 《Conservation biology》2016,30(6):1277-1287
Many argue that monitoring conducted exclusively by scientists is insufficient to address ongoing environmental challenges. One solution entails the use of mobile digital devices in participatory monitoring (PM) programs. But how digital data entry affects programs with varying levels of stakeholder participation, from nonscientists collecting field data to nonscientists administering every step of a monitoring program, remains unclear. We reviewed the successes, in terms of management interventions and sustainability, of 107 monitoring programs described in the literature (hereafter programs) and compared these with case studies from our PM experiences in Australia, Canada, Ethiopia, Ghana, Greenland, and Vietnam (hereafter cases). Our literature review showed that participatory programs were less likely to use digital devices, and 2 of our 3 more participatory cases were also slow to adopt digital data entry. Programs that were participatory and used digital devices were more likely to report management actions, which was consistent with cases in Ethiopia, Greenland, and Australia. Programs engaging volunteers were more frequently reported as ongoing, but those involving digital data entry were less often sustained when data collectors were volunteers. For the Vietnamese and Canadian cases, sustainability was undermined by a mismatch in stakeholder objectives. In the Ghanaian case, complex field protocols diminished monitoring sustainability. Innovative technologies attract interest, but the foundation of effective participatory adaptive monitoring depends more on collaboratively defined questions, objectives, conceptual models, and monitoring approaches. When this foundation is built through effective partnerships, digital data entry can enable the collection of more data of higher quality. Without this foundation, or when implemented ineffectively or unnecessarily, digital data entry can be an additional expense that distracts from core monitoring objectives and undermines project sustainability. The appropriate role of digital data entry in PM likely depends more on the context in which it is used and less on the technology itself. 相似文献
952.
Leila Mehrparvar Siyamak Safapour Mousa Sadeghi-Kiakhani Kamaladin Gharanjig 《Environmental Chemistry Letters》2016,14(4):533-539
The classical use of synthetic dyes is causing issues of environmental pollution and heath risk. As a consequence natural dyes are gaining interest, but the use of natural dyes still includes toxic reagents such as metals as mordants and acids to enhance color and yield. Therefore, we designed a new chitosan-polypropylene imine dendrimer hybrid at 0–2000 mg/L to treat wool before dyeing with cochineal. We compared dye exhaustion, color depth, color characteristics, and color fastness of the new process with dyed pristine and metal mordanted wool. Results show that wool pretreatment improved dye exhaustion from 48 to 88 %, shifted saturation point toward lower dye concentration from 3000 to 1000 mg/L, and improved color depth from 13.68 for pristine wool and 15.17 for metal mordanted wool to 23.89 for the new process. 相似文献
953.
954.
955.
International environmental agreements (IEAs) can coordinate abatement of transboundary pollutants. This paper investigates
how heterogeneous countries facing a stock pollutant might structure such an agreement. In particular, we examine how an IEA
might be implemented with a set of monetary transfers. The focus is on transfers that are time invariant, linear in emissions,
and consistent with budget balance. There is a range of such schemes that would induce efficient emissions. We provide a simple
and intuitive characterization of these penalties and describe how specific proposals might be chosen in order to facilitate
compliance and implementation. Our proposals are illustrated with a simple example. We show that heterogeneity reduces the
scope for penalty schemes to jointly satisfy desirable properties. 相似文献
956.
Kazuharu Yoshizuka Syouhei Nishihama Hideki Sato 《Environmental geochemistry and health》2010,32(4):297-302
The objective of this study was to survey the cation and anion contents of geothermal waters to gather fundamental information
on geographical variations. Sixteen sites in hot spring areas on the island of Kyushu in Japan were studied. The study focused
on the arsenic content of the samples. Very high arsenic concentrations (more than 0.1 mg/l) were detected in most of the
geothermal waters sampled. High contents of boron and fluoride (more than 1.0 mg/l) were also detected in some samples. Arsenic
removal was performed on a laboratory scale using columns packed with a magnetite-type adsorbent. The reduction of arsenic
contamination to a concentration of less than 0.01 mg/l could be achieved in the early stages of adsorption (bed volume = 200). 相似文献
957.
Environmentally Friendly Polyurethane Composites: Preparation, Characterization and Mechanical Properties 总被引:1,自引:0,他引:1
J. L. Zhang D. M. Wu D. Y. Yang F. X. Qiu 《Journal of Polymers and the Environment》2010,18(2):128-134
The waterborne polyurethane (PU) prepolymer was prepared based on isophorone diisocyanate (IPDI), polyester polyol (N220), dimethylol propionic acid (DMPA) and hydroxyethyl methyl acrylate (HEMA). The modified waterborne polyurethane–acrylate (PUA) emulsions were obtained with different proportions of acrylate (butyl acrylate and methyl methacrylate) and initiating agent by in situ dispersion technique. The structures and thermal properties of prepared PU and PUA were analyzed and characterized with FT-IR, UV–Vis spectroscopy and DSC. The PUA hybrid samples had lower glass transition temperature of hard segment and higher decomposition temperatures than PU sample. Performances of the emulsion and film were studied by means of apparent viscidity, particle size and polydispersity, surface tension and mechanical properties. The results indicated that the particle sizes of the PUA dispersions were larger than those of the pure PU and the solvent resistance, mechanical properties of PUA films was improved compare with the unmodified polyurethane film. The film had the biggest hardness and the least water absorption when the BA/MMA mass ratio 5:5 modified PU. The obtained PUA have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes. 相似文献
958.
959.
Satinder K. Brar Mausam Verma R.D. Tyagi R.Y. Surampalli 《Waste management (New York, N.Y.)》2010,30(3):504-520
Nanotechnology has widespread application in agricultural, environmental and industrial sectors ranging from fabrication of molecular assemblies to microbial array chips. Despite the booming application of nanotechnology, there have been serious implications which are coming into light in the recent years within different environmental compartments, namely air, water and soil and its likely impact on the human health. Health and environmental effects of common metals and materials are well-known, however, when the metals and materials take the form of nanoparticles – consequential hazards based on shape and size are yet to be explored. The nanoparticles released from different nanomaterials used in our household and industrial commodities find their way through waste disposal routes into the wastewater treatment facilities and end up in wastewater sludge. Further escape of these nanoparticles into the effluent will contaminate the aquatic and soil environment. Hence, an understanding of the presence, behavior and impact of these nanoparticles in wastewater and wastewater sludge is necessary and timely. Despite the lack of sufficient literature, the present review attempts to link various compartmentalization aspects of the nanoparticles, their physical properties and toxicity in wastewater and wastewater sludge through simile drawn from other environmental streams. 相似文献
960.