全文获取类型
收费全文 | 3482篇 |
免费 | 25篇 |
国内免费 | 43篇 |
专业分类
安全科学 | 86篇 |
废物处理 | 192篇 |
环保管理 | 319篇 |
综合类 | 554篇 |
基础理论 | 729篇 |
环境理论 | 3篇 |
污染及防治 | 1065篇 |
评价与监测 | 347篇 |
社会与环境 | 232篇 |
灾害及防治 | 23篇 |
出版年
2023年 | 45篇 |
2022年 | 107篇 |
2021年 | 148篇 |
2020年 | 71篇 |
2019年 | 59篇 |
2018年 | 124篇 |
2017年 | 136篇 |
2016年 | 161篇 |
2015年 | 92篇 |
2014年 | 162篇 |
2013年 | 247篇 |
2012年 | 175篇 |
2011年 | 228篇 |
2010年 | 162篇 |
2009年 | 151篇 |
2008年 | 151篇 |
2007年 | 152篇 |
2006年 | 111篇 |
2005年 | 139篇 |
2004年 | 172篇 |
2003年 | 162篇 |
2002年 | 116篇 |
2001年 | 84篇 |
2000年 | 39篇 |
1999年 | 40篇 |
1998年 | 19篇 |
1997年 | 28篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 20篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 18篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1979年 | 9篇 |
1975年 | 3篇 |
1970年 | 3篇 |
1968年 | 3篇 |
1966年 | 3篇 |
1964年 | 4篇 |
1961年 | 3篇 |
排序方式: 共有3550条查询结果,搜索用时 15 毫秒
731.
Twenty stomiatoid fish larvae (3.1 to 21,9 mm) belonging to the genera Bathophilus, Cyclothone, and Stomias were collected in plankton nets from surface waters over depths of 3 to 4 m from Biscayne Bay, Florida, USA. The adults are mesopelagic in the open water of the Florida Current and, therefore, these larvae were presumably advected in parcels of high salinity water into the shallows of Biscayne Bay by winds, tides, or currents. The presence of these larvae suggest that sewage discharged into the Florida Current may be recycling into coastal waters as well as into Biscayne Bay.Scientific Contribution No. 1403, University of Miami, Rosenstiel School of Marine and Atmospheric Science. The support of Environmental Protection Agency Contract FW QA 18050 DIU, Water Quality Office, Division of Water Quality Research is gratefully acknowledged. 相似文献
732.
733.
In three delphinid species (Pacific spotted dolphin, Stenella attenuata; common dolphin, Delphinus delphis; harbor porpoise, Phocoena phocoena) the enzyme lysozyme and the peptide group -defensins are demonstrated for the first time in cetaceans as products of the thick integument. Lysozyme was found between the lamellae of the stratum corneum, in the cells of the stratum spinosum, free cells of the dermis, and in endothelial cells of dermal blood vessels. -defensins (especially type 3) were clearly located in cells of the upper stratum spinosum, and concentrated between the upper five or six layers of the stratum corneum. The occurrence and localization of such substances that may serve as a non-specific defense against bacteria, fungi, algae, and ectoparasites, was known until now only for haired marine mammals with typical skin glands, like in pinnipeds.Communicated by O. Kinne, Oldendorf/Luhe 相似文献
734.
Aloisi de Larderel 《产业与环境》2003,(Z1)
环境预防战略,无论是清洁生产、生态效益还是污染防治,是改变不可持续生产和消费方式的最佳战略.自从它被引入《21世纪议程》后,政府和工商业越来越多地采用了清洁生产观念,并且为完善这一概念做出了巨大的努力. 相似文献
735.
736.
Luc A. Wauters Simon A. de Crombrugghe Nadia Nour Erik Matthysen 《Behavioral ecology and sociobiology》1995,37(3):189-193
In polygynous roe deer Capreolus capreolus, males are only slightly heavier than females and the overall sex ratio at birth is close to unity. We studied offspring sex ratio and litter size (range 1–4, n = 74) of culled females, in utero, which provided an opportunity to examine responses of sex ratio to maternal condition. Male embryos were heavier than their sisters, and male fawns (9 months old) heavier than female fawns, suggesting a higher growth rate in males. There was no evidence for differential mortality between the sexes from birth to 9 months old. Heavier adult females produced larger embryos than lighter, or primiparous females. The overall sex ratio of embryos did not differ from unity, but adult does had more male embryos (55%) than primiparous does (32%), and the proportion of male embryos in a litter increased with the mother's body mass. Litter size also tended to increase with maternal age and body mass. We argue that this pattern reflects adaptive variation in offspring sex ratio. 相似文献
737.
Wetland microcosms were used to evaluate the ability of constructed wetlands to remove extremely high concentrations of selenocyanate (SeCN-), arsenic (As), and boron (B) from wastewater generated by a coal gasification plant in Indiana. The wetland microcosms significantly reduced the concentrations of selenium (Se), As, B, and cyanide (CN) in the wastewater by 64%, 47%, 31%, and 30%, respectively. In terms of the mass of each contaminant, 79%, 67%, 57%, and 54% of the Se, As, B, and CN, respectively, loaded into the microcosms were removed from the wastewater. The primary sink for the retention of contaminants within the microcosms was the sediment, which accounted for 63%, 51%, and 36% of the Se, As, and B, respectively. Accumulation in plant tissues accounted for only 2-4%, while 3% of the Se was removed by biological volatilization to the atmosphere. Of the 14 plant species tested, cattail, Thalia, and rabbitfoot grass were highly tolerant of the contaminants and exhibited no growth retardation. Environmental toxicity testing with fathead minnow (Pimephales promelas) larvae confirmed that the water treated by the wetland microcosms was less toxic than untreated water. The data from the wetland microcosms support the view that constructed wetlands could be used to successfully reduce the toxicity of aqueous effluent contaminated with extremely high concentrations of SeCN-, As, and B, and that a pilot-scale wetland should therefore be constructed to test this in the field. Cattail, Thalia, and rabbitfoot grass would be suitable plant species to establish in such wetlands. 相似文献
738.
In the routine São Paulo state (Brazil) surface water quality-monitoring program, which includes the Salmonella microsome mutagenicity assay as one of its parameters, a river where water is taken and treated for drinking water purposes has repeatedly shown mutagenic activity. A textile dyeing facility employing azo-type dyes was the only identifiable source of mutagenic compounds. We extracted the river and drinking water samples with XAD4 at neutral and acidic pH and with blue rayon, which selectively adsorbs polycyclic compounds. We tested the industrial effluent, raw, and treated water and sediment samples with YG1041 and YG1042 and compared the results with the TA98 and TA100 strains. The elevated mutagenicity detected with YG-strains suggested that nitroaromatics and/or aromatic amines were causing the mutagenicity detected in the samples analyzed. Positive responses for the blue rayon extracts indicated that mutagenic polycyclic compounds were present in the water samples analyzed. The mutagen or mixture of mutagens present in the effluent and water samples cause mainly frameshift mutations and are positive with and without metabolic activation. The Salmonella assay combined with different extraction procedures proved to be very useful in the identification of the origin of the pollution and in the identification of the classes of chemical compounds causing the mutagenic activity in the river analyzed. 相似文献
739.
Fernández de Castro BM Prada Sánchez JM González Manteiga W Febrero Bande M Bermúdez Cela JL Hernández Fernández JJ 《Journal of the Air & Waste Management Association (1995)》2003,53(5):532-539
In this paper, we present an adaptation of the air pollution control help system in the neighborhood of a power plant in As Pontes (A Coru?a, Spain), property of Endesa Generación S.A., to the European Council Directive 1999/30/CE. This system contains a statistic prediction made half an hour before the measurement, and it helps the staff in the power plant prevent air quality level episodes. The prediction is made using neural network models. This prediction is compared with one made by a semiparametric model. 相似文献
740.
Lebo JA Almeida FV Cranor WL Petty JD Huckins JN Rastall A Alvarez DA Mogensen BB Johnson BT 《Chemosphere》2004,54(8):1217-1224
Analyses of triolein-containing semipermeable membrane devices (SPMDs) have sometimes been impeded by interferences caused by impurities endemic to triolein that codialyze with the analytes. Oleic acid and methyl oleate have been the most troublesome of these impurities because of their relatively high concentrations in triolein and because significant residues of both can persist even after size exclusion chromatographic (SEC) fractionation. These residues have also been blamed for false-positive signals during bioindicator testing of SPMD dialysates. To prevent these problems, a simple, cost-effective procedure was developed for purifying triolein destined for use in SPMDs: the bulk triolein is repeatedly (6x) partitioned against methanol. Tests of the procedure show that 14C-oleic acid is completely removed from the triolein. After SEC fractionation, dialysates of standard-size SPMDs made with the purified triolein contain less than 5 microg of methyl oleate as compared to sometimes more than 500 microg for dialysates (also after SEC) of SPMDs made with unpurified triolein. Gas chromatographic analyses with flame ionization and electron capture detection show that the purification treatment also greatly reduces the number and size of peaks caused by unidentified contaminants in the triolein. Microtox basic assay of dialysates of SPMDs shows that those made with the purified triolein have lower acute toxicities than dialysates of SPMDs made with unpurified triolein. Yeast estrogen screen (YES) testing of SPMDs fabricated with unpurified and purified triolein demonstrates that the purification process removes all background estrogenic activity. 相似文献