全文获取类型
收费全文 | 268篇 |
免费 | 3篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 12篇 |
环保管理 | 52篇 |
综合类 | 38篇 |
基础理论 | 62篇 |
环境理论 | 1篇 |
污染及防治 | 71篇 |
评价与监测 | 17篇 |
社会与环境 | 11篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 32篇 |
2012年 | 10篇 |
2011年 | 21篇 |
2010年 | 7篇 |
2009年 | 8篇 |
2008年 | 13篇 |
2007年 | 20篇 |
2006年 | 13篇 |
2005年 | 19篇 |
2004年 | 6篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有278条查询结果,搜索用时 0 毫秒
131.
Tokuchi Naoko Ohte Nobuhito Osaka Ken’ichi Katsuyama Masanori 《Environmental monitoring and assessment》2013,185(1):855-863
Pine wilt disease (PWD) is caused by a non-native pest that has spread extensively throughout Japan. Previous research has indicated that most infected trees have died and the litter deposited has resulted in changes to stream-water chemistry, particularly increased nitrate (NO 3 ? ) concentrations. In this study, we divided stream nitrogen (N) export into N loss due to PWD and baseline N leakage without disturbance based on long-term monitoring. The annual N export was 110.0 mol N ha?1 year?1 in 1990 and 749.8 mol N ha?1 year?1 in 1997, and had decreased to 37.0 mol N ha?1 year?1 in 2005. N export under PWD influence was estimated to be 3697 mol N ha?1, and N loss due to PWD was 2810 mol N ha?1. N loss due to PWD was three times larger than baseline N leakage for the disturbed period. These changes in plant–herbivore relationships could affect N status in a forest ecosystem. So-called “semi-natural” disturbances related to non-native species invasion and increases of atmospheric N deposition caused by human activity will increase. Long-term monitoring studies of various aspects are necessary to offer insight into this ecosystem. 相似文献
132.
We developed a novel polymer type sulfoxide-modified solid phase enabling to achieve selective separation of polychlorinated biphenyls (PCBs) from insulation oil. In this study, firstly we prepared base-polymer based on the concept of the molecular imprinting to capture PCBs in selectively, then, the sulfoxide groups were modified on the pore surface of base-polymers by changing preparation methods. As results of liquid chromatographic analyses for the polymers as columns, the base-polymer prepared by xylene as a porogenic solvent showed selective retention ability for chlorinated aromatic compounds by the porogen imprinting effect. Additionally, the polymer-type sulfoxide solid phases showed highly retention ability for PCBs by increasing amount of introduced sulfoxide groups. Consequently, the results of separation of PCBs comparing to insulation oil suggested that the prepared solid phase can be used for the selective separation of PCBs at the same level as a commercially available media utilized for the regulated method. 相似文献
133.
Howard J Trotz MA Thomas K Omisca E Chiu HT Halfhide T Akiwumi F Michael R Stuart AL 《Environmental monitoring and assessment》2011,179(1-4):555-573
The Low Carbon Development Strategy proposed in June 2009 by the government of Guyana in response to the Reducing Emissions from Deforestation and Forest Degradation in Developing Countries program has triggered evaluation of forest-related activities, thereby acting as a catalyst for improvements in Guyana's small- to medium-scale gold mining industry. This has also shed light on areas committed to conservation, something that has also been handled by Non Governmental Organizations. This paper compares water quality and mercury concentrations in sediment from four main areas in Guyana, two that are heavily mined for gold using mercury amalgamation methods (Arakaka and Mahdia) and two that are considered conservation areas (Iwokrama and Konashen). Fifty-three sediment and soil mercury loadings ranged from 29 to 1,200 ng/g and averaged 215 ± 187 ng/g for all sites with similar averages in conservation and mining areas. Sediment loadings are within the range seen in French Guiana and Suriname, but conservation area samples had higher loadings than the corresponding uncontaminated baselines. Type of ore and location in the mining process seemed to influence mercury loadings. Mercury sediment loadings were slightly positively correlated with pH (correlation coefficient = 0.2; p value < 0.001) whereas no significant correlations were found with dissolved oxygen or turbidity. 相似文献
134.
Lokesh Padhye Ken Rainwater W Andrew Jackson Audra Morse 《Water environment research》2007,79(2):140-146
The major objectives of this work were to operate and construct an autohydrogenotrophic reactor and estimate perchlorate degradation kinetics. The results show that autohydrogenotrophic bacteria were cultured in the reactor and capable of removing 3.6 mg/d of perchlorate in the presence of excess hydrogen (99% removal). The reactor was successful in treating the average influent perchlorate concentration of 532 microg/L to the level of 3 microg/L. A first-order relationship was obtained between the concentration of active biomass in the reactor and the hydraulic retention time for the given amount of substrate. During the kinetic loading study, perchlorate removal ranged from 100 to 50%. The kinetic rate of perchlorate degradation observed in this study was 1.62 hr(-1). The significant degradation of perchlorate in these samples indicates the ubiquity of perchlorate-reducing organisms. Additionally, nitrate was simultaneously removed during water treatment (greater than 90% removal). Because of the excess levels of hydrogen, simultaneous removal of nitrate was not believed to significantly affect perchlorate removal. The area of concern was the lack of complete control over biological treatment. The growth of sulfate-reducing organisms in the reactor negatively affected perchlorate removal efficiency. There were no significant effects observed on the dissolved organic carbon and total suspended solids concentration of the effluent, suggesting that the treatment did not produce a large amount of biomass washout. 相似文献
135.
Alfredo Mahar Francisco A. Lagmay Bernard Alan Racom Ken Adrian Aracan Jenalyn Alconis-Ayco Ivan Lester Saddi 《环境科学学报(英文版)》2017,29(9):13-23
The Philippines being a locus of tropical cyclones, tsunamis, earthquakes and volcanic eruptions, is a hotbed of disasters. These natural hazards inflict loss of lives and costly damage to property. Situated in a region where climate and geophysical tempest is common, the Philippines will inevitably suffer from calamities similar to those experienced recently. With continued development and population growth in hazard prone areas, it is expected that damage to infrastructure and human losses would persist and even rise unless appropriate measures are immediately implemented by government. In 2012, the Philippines launched a responsive program for disaster prevention and mitigation called the Nationwide Operational Assessment of Hazards (Project NOAH), specifically for government warning agencies to be able to provide a 6 hr lead-time warning to vulnerable communities against impending floods and to use advanced technology to enhance current geo-hazard vulnerability maps. To disseminate such critical information to as wide an audience as possible, a Web-GIS using mashups of freely available source codes and application program interface (APIs) was developed and can be found in the URLs http:// noah.dost.gov.ph and http://noah.up.edu.ph/. This Web-GIS tool is now heavily used by local government units in the Philippines in their disaster prevention and mitigation efforts and can be replicated in countries that have a proactive approach to address the impacts of natural hazards but lack sufficient funds. 相似文献
136.
The fossil record of late Campanian tyrannosauroids of western North America has a geographic gap between the Northern Rocky
Mountain Region (Montana, Alberta) and the Southwest (New Mexico, Utah). Until recently, diagnostic tyrannosauroids from the
Southwest were unknown until the discovery of Bistahieversor sealeyi from the late Campanian of New Mexico. Here we describe an incomplete skull and postcranial skeleton of an unusual tyrannosaurid
from the Kaiparowits Formation (Late Cretaceous) of Utah that represents a new genus and species, Teratophoneus curriei. Teratophoneus differs from other tyrannosauroids in having a short skull, as indicated by a short and steep maxilla, abrupt angle in the
postorbital process of the jugal, laterally oriented paroccipital processes, short basicranium, and reduced number of teeth.
Teratophoneus is the sister taxon of the Daspletosaurus + Tyrannosaurus clade and it is the most basal North American tyrannosaurine. The presence of Teratophoneus suggests that dinosaur faunas were regionally endemic in the west during the upper Campanian. The divergence in skull form
seen in tyrannosaurines indicates that the skull in this clade had a wide range of adaptive morphotypes. 相似文献
137.
Learning,retention and coding of nest-associated visual cues by the Australian desert ant, <Emphasis Type="Italic">Melophorus bagoti</Emphasis> 总被引:3,自引:0,他引:3
Ajay Narendra Aung Si Danielle Sulikowski Ken Cheng 《Behavioral ecology and sociobiology》2007,61(10):1543-1553
A variety of social insects use visual cues for homing. In this study, we examine the possible factors affecting the learning
and retention of nest-associated visual cues by the Australian desert ant Melophorus bagoti and the manner in which such cues are encoded by foraging ants. We placed four prominent cylindrical landmarks around a nest
and trained foragers from that nest to a food source. Ants were tested with the landmark array in a distant testing field
after (1) a known number of exposures to the landmarks (1, 3, 7 or 15 trials, spread over a period of 1 day, 2 days or ≥3 days)
and (2) after a known period of delay (0, 24, 48, 96 or 192 h). The results show that a combination of an increase in training
trials and an increase in number of training days affected the acquisition of landmark memory. Moreover, once the landmarks
were learnt, they became a part of long-term memory and lasted throughout the ants’ foraging lifetime. To examine visual cue
encoding behaviour, ants trained under similar conditions for 4 days were tested with (1) an identical landmark array, (2)
landmarks of the same size used in training, but placed at twice the distance from each other, and (3) landmarks whose dimensions
were doubled and placed at twice the distance from each other. In conditions (1) and (3), the ants searched extensively at
the centre of the four landmarks, suggesting that, similar to the Saharan ant (genus Cataglyphis) and the honeybee, M. bagoti too uses a snapshot to match the view of the landmarks around the nest. But contrary to the snapshot model, in condition
(2), the ants did not search extensively at the centre of the landmarks, but searched primarily 0.5 m from the landmark, the
distance from each landmark to the nest during training. We discuss how various search models fare in accounting for these
findings. 相似文献
138.
Keiichi Honda Hiroshi Minematsu Ken’ichiro Muta Hisashi ?mura Wataru Nishii 《Chemoecology》2012,22(1):55-63
The sulfur butterfly, Colias erate, utilizes various legumes as host plants. We examined the chemical constituents of its primary host plant, Trifolium repens (white clover), to identify phytochemicals inducing oviposition by C. erate females. Since one of the four aqueous subfractions prepared from a methanolic extract of the plant has previously been shown
to be the most responsible for the oviposition-stimulatory activity exerted by the plant, chemical analyses were conducted
of the fraction concerned. Activity-directed fractionation of the subfraction by ion-exchange chromatography revealed that
the key substance(s) resided in the neutral fraction. Preparative TLC of the neutral fraction and subsequent spectral analyses
identified d-(+)-pinitol, glycerin, methyl β-d-glucoside, and myo-inositol as characteristic components together with ubiquitous sugars (e.g., sucrose and glucose). Of these, only pinitol
singly evoked significant oviposition responses at concentrations over 0.05%. In dual-choice bioassays, however, females laid
significantly more eggs on pinitol solutions admixed with glycerin or methyl β-d-glucoside than on pinitol alone. Two cyanoglucosides, linamarin, and lotaustralin, occurring in the other aqueous subfractions,
also synergistically increased the oviposition response in combination with pinitol. The results clearly indicated that pinitol
is a crucial oviposition stimulant involved in host recognition, while glycerin, methyl β-d-glucoside, linamarin, and lotaustralin function as synergists. We further examined the oviposition responses of C. erate females to aqueous fractions, along with their chemical compositions, that had been prepared from five other host plants
and a non-host plant, Aristolochia debilis (Aristolochiaceae), on which oviposition occasionally took place in an outdoor cage during the experiments.
The plant species accepted by ovipositing females were all found to contain pinitol in amounts enough to induce egg laying
by the butterfly, thus leading to the conclusion that pinitol serves as the essential mediator in recognizing and accepting
potential host plants. 相似文献
139.
140.
Snelder TH Leathwick JR Dey KL Rowden AA Weatherhead MA Fenwick GD Francis MP Gorman RM Grieve JM Hadfield MG Hewitt JE Richardson KM Uddstrom MJ Zeldis JR 《Environmental management》2007,39(1):12-29
We describe here the development of an ecosystem classification designed to underpin the conservation management of marine environments in the New Zealand region. The classification was defined using multivariate classification using explicit environmental layers chosen for their role in driving spatial variation in biologic patterns: depth, mean annual solar radiation, winter sea surface temperature, annual amplitude of sea surface temperature, spatial gradient of sea surface temperature, summer sea surface temperature anomaly, mean wave-induced orbital velocity at the seabed, tidal current velocity, and seabed slope. All variables were derived as gridded data layers at a resolution of 1 km. Variables were selected by assessing their degree of correlation with biologic distributions using separate data sets for demersal fish, benthic invertebrates, and chlorophyll-a. We developed a tuning procedure based on the Mantel test to refine the classification's discrimination of variation in biologic character. This was achieved by increasing the weighting of variables that play a dominant role and/or by transforming variables where this increased their correlation with biologic differences. We assessed the classification's ability to discriminate biologic variation using analysis of similarity. This indicated that the discrimination of biologic differences generally increased with increasing classification detail and varied for different taxonomic groups. Advantages of using a numeric approach compared with geographic-based (regionalisation) approaches include better representation of spatial patterns of variation and the ability to apply the classification at widely varying levels of detail. We expect this classification to provide a useful framework for a range of management applications, including providing frameworks for environmental monitoring and reporting and identifying representative areas for conservation. 相似文献