全文获取类型
收费全文 | 688篇 |
免费 | 27篇 |
国内免费 | 9篇 |
专业分类
安全科学 | 26篇 |
废物处理 | 15篇 |
环保管理 | 153篇 |
综合类 | 136篇 |
基础理论 | 183篇 |
环境理论 | 3篇 |
污染及防治 | 125篇 |
评价与监测 | 52篇 |
社会与环境 | 24篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 11篇 |
2022年 | 7篇 |
2021年 | 20篇 |
2020年 | 28篇 |
2019年 | 26篇 |
2018年 | 28篇 |
2017年 | 31篇 |
2016年 | 34篇 |
2015年 | 39篇 |
2014年 | 23篇 |
2013年 | 52篇 |
2012年 | 39篇 |
2011年 | 62篇 |
2010年 | 36篇 |
2009年 | 26篇 |
2008年 | 36篇 |
2007年 | 35篇 |
2006年 | 41篇 |
2005年 | 24篇 |
2004年 | 17篇 |
2003年 | 24篇 |
2002年 | 19篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有724条查询结果,搜索用时 140 毫秒
141.
Directing Research to Reduce the Impacts of Nonindigenous Species 总被引:19,自引:0,他引:19
142.
Hogrefe O Schwab JJ Drewnick F Lala GG Peters S Demerjian KL Rhoads K Felton HD Rattigan OV Husain L Dutkiewicz VA 《Journal of the Air & Waste Management Association (1995)》2004,54(9):1040-1060
Several collocated semicontinuous instruments measuring particulate matter with particle sizes < or =2.5 microm (PM2.5) sulfate (SO4(2-)) and nitrate (NO3-) were intercompared during two intensive field campaigns as part of the PM2.5 Technology Assessment and Characterization Study. The summer 2001 urban campaign in Queens, NY, and the summer 2002 rural campaign in upstate New York (Whiteface Mountain) hosted an operation of an Aerosol Mass Spectrometer, Ambient Particulate Sulfate and Nitrate Monitors, a Continuous Ambient Sulfate Monitor, and a Particle-Into-Liquid Sampler with Ion Chromatographs (PILS-IC). These instruments provided near real-time particulate SO4(2-) and NO3- mass concentration data, allowing the study of particulate SO4(2-)/NO3- diurnal patterns and detection of short-term events. Typical particulate SO4(2-) concentrations were comparable at both sites (ranging from 0 to 20 microg/m3), while ambient urban particulate NO3- concentrations ranged from 0 to 11 microg/m3 and rural NO3- concentration was typically less than 1 microg/m3. Results of the intercomparisons of the semicontinuous measurements are presented, as are results of the comparisons between the semicontinuous and time-integrated filter-based measurements. The comparisons at both sites, in most cases, indicated similar performance characteristics. In addition, charge balance calculations, based on major soluble ionic components of atmospheric aerosol from the PILS-IC and the filter measurements, indicated slightly acidic aerosol at both locations. 相似文献
143.
Anaerobic and aerobic (AnA) and completely aerobic (CA) sequencing-batch reactors (SBRs) were used to investigate the suitability of the AnA process for treating phosphorus (P)-deficient wastewaters with highly variable influent chemical oxygen demand (COD) loading. Both SBRs were subjected to influent COD loading patterns (LPs) that simulated (1) daily COD loading fluctuations, (2) weekend shutdowns, and (3) long weekend or holiday shutdowns. During LP 1, the AnA SBR produced lower average effluent soluble phosphorus concentrations than CA SBR (0.4 vs. 1.0 mgP/L). A similar result was observed during LP 2, but effluent acetate was detected after the first high COD loading cycle of the weekday loading period. During LP 3, the volatile suspended solids content of both reactors dropped sharply, and the effluent quality of both SBRs deteriorated. Model predictions suggest that the AnA process is stable when treating LP 1, but eventually fails when treating LP 2. 相似文献
144.
Sapozhnikova Y Zubcov N Hungerford S Roy LA Boicenco N Zubcov E Schlenk D 《Chemosphere》2005,60(2):196-205
The Dniester River is one of the largest rivers in Eastern Europe and receives input from numerous anthropogenic activities. In October 2001, fish samples (Abramis brama, Rutilus rutilus heckeli, Perca fluviatilis, Chondrostoma nasus, Carassius auratus gibelio, and Cyprinus carpio) were collected and analyzed for metals and various pesticides. Maximum total DDT pesticide concentrations were between 27.7 and 34.2 ng/g wet weight in muscles and gonads, respectively. DDE isomers comprised up to 70% of total DDT measurement in fish tissues, indicating historical rather than recent DDT pollution. Chlordane and lindane were also detected in amounts up to 37 and 76 ng/g wet weight in gonads, respectively. Among organophosphorous pesticides, malathion showed extremely high concentrations--3 microg/g wet weight in muscles and 46 microg/g wet weight in gonads, indicating recent exposure. Copper concentrations in muscles (1.8-7.2 microg/g) exceeded Threshold Effect Concentrations for copper in fish. Detection of high concentrations of malathion and copper in fish tissues indicated potential anthropogenic stress for more sensitive aquatic biota, likely from agricultural sources in the Dniester River. 相似文献
145.
Accumulation of metals,trace elements and semi-volatile organic compounds on exterior window surfaces in Baltimore 总被引:2,自引:0,他引:2
Liu QT Diamond ML Gingrich SE Ondov JM Maciejczyk P Stern GA 《Environmental pollution (Barking, Essex : 1987)》2003,122(1):51-61
Organic films have been found to develop on window surfaces [Diamond et al., Environmental Science and Technology 34 (2000a) 2900]. The film contains organic compounds that are in dynamic equilibrium with the gas-phase in air, and organic and inorganic compounds and elements associated with deposited air particles. In this study, the exterior surfaces of windows were sampled in downtown and suburban Baltimore, Maryland. Higher concentrations of PCBs, PAH, metals and trace elements were found at downtown than a suburban site. PCBs in the films at downtown sites were dominated by penta and hexa homologue groups and PAH signatures resembled that of vehicle emissions. Twenty-six metals and trace elements were separated into two groups according to their enrichment factors (EF). Ag, Hg, Se, Sb and Zn had EF > 100, suggesting anthropogenic sources of these metals in the films; whereas Fe, Ca, Co, Cr and others had EF <10, suggesting a crustal origin. An unusual profile dominated by deca- and nona- PCBs and relatively higher concentrations of Ag, Hg and Zn may be attributable to emissions from a medical waste incinerator. Dry deposition fluxes of selected metals on windows were 1.4-94 times higher on windows with than without films, indicating that the film increases the dry deposition of particles and their associated chemicals. This implies that film development, which is associated with elevated VOC and SOC emissions to urban air, will increase film development that will, in turn, increase the accumulation of other atmospherically deposited constituents such as metals. 相似文献
146.
Sarah?R.?PrykeEmail author Staffan?Andersson 《Behavioral ecology and sociobiology》2003,53(6):393-401
In breeding plumage, the African male red-shouldered widowbirds (Euplectes axillaris) are black except for red carotenoid-based epaulets ('shoulder patches'), similar to the well-studied American red-winged blackbirds (Agelaius phoeniceus). To experimentally test the signal function of the red epaulets in male red-shouldered widowbirds, we manipulated epaulet colour and size (within natural variation), and observed the effects in two competitive contexts. First, in captivity, unfamiliar males with epaulets of different size or redness were staged in dyadic contests over food. Only epaulet manipulations significantly affected contest outcome; red epaulet males out-competed orange and control males, which in turn dominated blackened (no epaulet) males. Epaulet size manipulations had particularly strong effects; enlarged epaulet males vigorously defeated smaller epaulet males within colour treatments, whereas the independent effect of 'redness' (i.e., within size treatments) was much weaker. Second, in a field experiment, epaulets were manipulated prior to territory establishment. Males with enlarged epaulets acquired territories, whereas most males with blackened or reduced signals failed to obtain territories. Furthermore, among the territorial males, birds with enlarged epaulets defended larger territories and spent less time in boundary signalling, yet they received fewer intrusions from conspecifics. In contrast, epaulet manipulations had no effect on either female visitation rates or subsequent female settlement. These results concur with recent studies and suggest that the carotenoid-based epaulets of red-shouldered widowbirds are status signals, sexually selected through male contest competition for territories. 相似文献
147.
Waterbird Communities and Habitat Relationships in Coastal Pastures of Northern California 总被引:2,自引:0,他引:2
We examined waterbird assemblages (diversity, composition, and species' densities) in 20 pastures near Humboldt Bay, California, in relation to habitat characteristics (vegetation height, soil penetrability, water depth), abundance of invertebrates (worms and other invertebrates), and presence of livestock. From October 1991 to May 1992 we observed 29 species and 10,776 birds, most (78%) of which foraged. Nonrandom pasture use by birds resulted in a highly clumped spatial distribution (s2 :{ovbar>x} ratio = 42.1). Habitat characteristics of pastures correlated with this nonrandom pattern: waterbird diversity and densities of three sandpiper species and one gull species correlated negatively ( r = −0.61 and r = −0.44 to −0.67, respectively) with vegetation height; densities of two plover species correlated negatively ( r = −0.39 and −0.45) with soil penetrability; and waterfowl densities correlated positively with water depth ( r = 0.97). Species composition varied among pastures. Wading birds used pastures with tall vegetation, shorebirds and gulls frequented short-grass pastures, and waterfowl used flooded pastures of waterbirds and their densities increased in association with livestock.In coastal areas where much intertidal habitat has been reclaimed as postureland, pastures offered valuable habitats to nonbreeding waterbirds. We suggest that grazing in coastal pastures can be used to provide a mosaic of vegetation heights, which would yield greater waterbird diversity as well as higher densities of some species. 相似文献
148.
Fetal loss through miscarriage or termination of pregnancy for genetic reasons often provokes the grief of bereavement. This is not fully understood, and the extent of the distress is often underestimated by professionals and family alike. We have examined elements of the normal bereavement process and have found that they may occur in specific and accentuated forms in mid-trimester fetal loss. We discuss our findings in the light of the attachment theory—a psychodynamic model for understanding grief reactions. 相似文献
149.
Meena Upadhyaya Alan Fryer Graham Foat Denise Robinson Oliver Quarrell Adrian Roberts P. S. Harper 《黑龙江环境通报》1990,10(9):593-603
Chorionic villi were sampled from 125 women who requested prenatal diagnosis, either for genetic disorders or because of advanced maternal age. Of these, 105 samples were obtained by the transcervical route and 20 were obtained by the transabdominal approach. The sampling success rate was 97 per cent (122/125). The mean maternal age of the patients was 31 years (range 17–44) and the mean gestational age at which the chorionic villus sampling was performed was 10 weeks (range 7–13 weeks). Seventy-four of these diagnoses involved the use of DNA markers. The minimal size of the sample used for DNA diagnosis was 5 mg. Maternal contamination was detected in two samples. A diagnosis was provided on all but two samples. The fetal loss rate was high initially but fell to 1·9 per cent in 1988. 相似文献
150.
Dr Joyce C. Harper Edith Coonen Alan H. Handyside Robert M. L. Winston Anton H. N. Hopman Joy D. A. Delhanty 《黑龙江环境通报》1995,15(1):41-49
We have previously detected chromosome abnormalities in human embryos whilst identifying the sex for preimplantation diagnosis of X-linked disease. In this study we assess the incidence of these abnormalities, both for sex chromosomes and autosomes 1 and 17, using dual fluorescent in situ hybridization (FISH). Sixty-nine normally fertilized embryos of good morphology at the 6–10 cell stage (day 3 post-insemination) were examined. The embryos were spread whole using HCl and Tween 20 to dissolve the cytoplasm. Thirty-four embryos were analysed for the sex chromosomes and 35 for autosomes 1 and 17. All probes were directly labelled with fluorochromes allowing analysis in 2 h. Control lymphocytes demonstrated that the probes were of high specificity. For the sex chromosomes, five embryos were mosaic (15 per cent) with the remaining 29 being uniformly XX or XY. In no case was an XX nucleus found in an otherwise XY embryo, indicating that even though mosaicism for the sex chromosomes is present, such abnormalities would not lead to a misdiagnosis of sex. For the autosomes, 16 embryos were abnormal (46 per cent); one embryo was triploid, one was monosomic for chromosome 1, and ten others were diploid mosaics (three diploid/aneuploid, three diploid/polyploid, and four diploid/haploid). A further four embryos had variable chromosome numbers in the majority of nuclei which appeared to be the result of uncontrolled mitotic division. The presence of haploidy or double monosomy, which occurred in 15 per cent of nuclei, has important implications for the diagnosis of trisomies and dominant disorders. 相似文献