全文获取类型
收费全文 | 410篇 |
免费 | 7篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 19篇 |
废物处理 | 18篇 |
环保管理 | 75篇 |
综合类 | 56篇 |
基础理论 | 89篇 |
环境理论 | 1篇 |
污染及防治 | 93篇 |
评价与监测 | 26篇 |
社会与环境 | 31篇 |
灾害及防治 | 12篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 22篇 |
2015年 | 6篇 |
2014年 | 15篇 |
2013年 | 32篇 |
2012年 | 21篇 |
2011年 | 19篇 |
2010年 | 18篇 |
2009年 | 23篇 |
2008年 | 32篇 |
2007年 | 18篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 16篇 |
2002年 | 5篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1961年 | 1篇 |
1958年 | 3篇 |
1955年 | 3篇 |
1954年 | 1篇 |
排序方式: 共有420条查询结果,搜索用时 15 毫秒
301.
302.
In designing a photocatalytic oxidation (PCO) system for a given air pollution source, destruction rates for volatile organic compounds (VOCs) are required. The objective of this research was to develop a systematic method of predicting PCO rate constants by correlating rate constants with physical-chemical characteristics of compounds. Accordingly, reaction rate constants were determined for destruction of volatile organics over a titanium dioxide (TiO2) catalyst in a continuous mixed-batch reactor. It was found that PCO rate constants for alkanes and alkenes vary linearly with gas-phase ionization potential (IP) and with gas-phase hydroxyl radical reaction rate constant. The correlations allow rates of destruction of compounds not tested in this research to be predicted based on physical-chemical characteristics. 相似文献
303.
T. Taylor Eighmy Bradley S. Crannell James E. Krzanowski Leslie G. Butler Frank K. Cartledge Earl F. Emery J. Dykstra Eusden Jr Elisabeth L. Shaw Carl A. Francis 《Waste management (New York, N.Y.)》1998,18(6-8)
The use of soluble PO43− as a heavy metal chemical stabilization agent was evaluated for a dust generated from melting or vitrification of municipal solid waste combustion residues. Vitrification dusts contain high concentrations of volatile elements such as Cl, Na, K, S, Pb, and Zn. These elements are present in the dusts largely as simple salts (e.g. PbCl2, ZnSO4) which are highly leachable. At an experimental dose of 0.4 moles of soluble PO43− per kg of residue, the pH-dependent leaching (pH 5,7,9) showed that the treatment was able to reduce equilibrium concentrations by factors of 3 to 100 for many metals; particularly Cd, Cu, Pb and Zn. Bulk and surface spectroscopies showed that the insoluble reaction products are tertiary metal phosphate [e.g. Zn3(PO4)2] and apatite [e.g. Pb5(PO4)3Cl] family minerals. Geochemical thermodynamic equilibrium modeling showed that apatite family and tertiary metal phosphate phases act as controlling solids for the equilibrium concentrations of Ca2+, Zn2+, Pb2+, Cu2+, and Cd2+ in the leachates during pH-dependent leaching. Both end members and ideal solid solutions were seen to be controlling solids. Soluble phosphate effectively converted soluble metal salts into insoluble metal phosphate phases despite the relatively low doses and dry mixing conditions that were used. Soluble phosphate is an effective stabilization agent for divalent heavy metals in melting dusts where leachable metals are present in high concentrations. 相似文献
304.
We have developed a basic concept for studying cell biological phenomena using an interdisciplinary approach starting from organic chemistry. Based on structural information available for a given biological phenomenon, unsolved chemical problems are identified. For their solution, new synthetic pathways and methods are developed, which reflect the state of the art in synthesising lipidated peptide conjugates. These compounds are used as molecular probes for the investigation of biological phenomena that involve both the determination of biophysical properties and cell biological studies. The interplay between organic synthesis, biophysics and cell biology in the study of protein lipidation may open up new and alternative opportunities to gain knowledge about the biological phenomenon that could not be obtained by employing biological techniques alone. This fruitful combination is highlighted using the Ras protein as an outstanding example. Included herein is: the development of methods for the synthesis of Ras-derived peptides and fully functional Ras proteins, the determination of the biophysical properties, in particular the ability to bind to model membranes, and finally the use of synthetic Ras peptides and proteins in cell biological experiments. 相似文献
305.
306.
A survey of residents in an area subject to annual toxic cyanobacterial blooms was undertaken to examine potential health effects of cyanobacteria toxins. The survey assessed the health of marine recreational water users in Deception Bay/Bribie Island area in northern Moreton Bay, Queensland, which is exposed to blooms of the nuisance and potentially harmful cyanobacterium Lyngbya majuscula. A postal survey was mailed to 5000 residents with a response rate of 27%. High numbers of people (78%) responding to the survey reported recreational water activity in Moreton Bay. Of those having marine recreational water activity, 34% reported at least one symptom after exposure to marine waters, with skin itching the most reported (23%). Younger participants had greater water exposure and symptoms than older participants. Participants with greater exposures were more likely to have skin and eye symptoms than less exposed groups, suggesting agents in the marine environment may have contributed to these symptoms. Of those entering Moreton Bay waters 29 (2.7%) reported severe skin symptoms, 12 of whom attended a health professional. Six (0.6%) reported the classic symptoms of recreational water exposure to L. majuscula, severe skin symptoms in the inguinal region. Participants with knowledge of L. majuscula were less likely to report less skin, gastrointestinal and fever and headache symptoms. In conclusion, high numbers of participants reported symptoms after exposure to waters subject to L. majuscula blooms but only a small number appeared to be serious in nature suggesting limited exposure to toxins. 相似文献
307.
308.
Melanie Schubert Carsten Schradin Heiko G. Rödel Neville Pillay David O. Ribble 《Behavioral ecology and sociobiology》2009,64(2):257-264
Mate guarding is predicted to be one of the driving forces for the evolution of monogamy, but supporting evidence in free-living
mammals is rare. The goals of our study were three-pronged. First, we tested if mate guarding, measured as intrapair distance,
occurs as a behavioral tactic in round-eared sengis (Macroscelides proboscideus), a socially monogamous species lacking paternal care and in which females breed asynchronously, producing 2–3 litters during
an 8-month long breeding season. Second, we determined if mate guarding involves costs which we identified as changes in male
body mass. Third, we investigated whether variation in individual investment in mate guarding depended on the males’ body
mass and the number of neighboring males. Field data were collected in a semidesert in South Africa using radio-tracking,
trapping, and direct observations during three successive breeding seasons. Mate guarding strongly depended on the females’
reproductive state, and all males started to guard their mates prior to and during estrus, as exemplified by reduced intrapair
distance. Mate guarding incurred costs: overall, males lost about 5% of body mass. Male body mass loss and initial body mass
were negatively related to the intensity of precopulatory mate guarding. Furthermore, during estrus intrapair distance was
inversely correlated with the number of neighboring males. The results show that mate guarding is the predominant male tactic
in round-eared sengis. However, since mate guarding imposed costs, males may balance benefits and costs associated with guarding
by varying their effort in relation to their physical capabilities and the competitive environment. 相似文献
309.
Measuring terrestrial subsidies to aquatic food webs using stable isotopes of hydrogen 总被引:4,自引:0,他引:4
Understanding river food webs requires distinguishing energy derived from primary production in the river itself (autochthonous) from that produced externally (allochthonous), yet there are no universally applicable and reliable techniques for doing so. We compared the natural abundance stable isotope ratios of hydrogen (deltaD) of allochthonous and autochthonous energy sources in four different aquatic ecosystems. We found that autochthonous organic matter is uniformly far more depleted in deuterium (lower deltaD values) than allochthonous: an average difference of approximately 100% per hundred. We also found that organisms at higher trophic levels, including both aquatic invertebrates and fish, have deltaD values intermediate between aquatic algae and terrestrial plants. The consistent differences between leaves and algae in deltaD among these four watersheds, along with the intermediate values in higher trophic levels, indicate that natural abundance hydrogen isotope signatures are a powerful tool for partitioning energy flow in aquatic ecosystems. 相似文献
310.
Several researchers have examined the role of microfinance institutions (MFIs) in poverty alleviation, but the part that they play in disaster risk reduction remains unaddressed. Through an empirical study of Hatiya Island, one of the most vulnerable coastal communities of Bangladesh, this research evaluates perceptions of MFI support for the disaster risk reduction, response, and recovery process. The findings reveal no change in relation to risk reduction and income and occupation aspects for more than one‐half of the clients of MFIs. In addition, only 26 per cent of them have witnessed less damage as a result of being members of MFIs. One can argue, though, that the longer the membership time period the better the disaster preparedness, response, and recovery process. The outcomes of this study could help to guide the current efforts of MFIs to enhance the ability of coastal communities to prepare for and to recover from disasters efficiently and effectively. 相似文献