全文获取类型
收费全文 | 2512篇 |
免费 | 37篇 |
国内免费 | 41篇 |
专业分类
安全科学 | 87篇 |
废物处理 | 174篇 |
环保管理 | 233篇 |
综合类 | 362篇 |
基础理论 | 459篇 |
污染及防治 | 861篇 |
评价与监测 | 235篇 |
社会与环境 | 165篇 |
灾害及防治 | 14篇 |
出版年
2024年 | 2篇 |
2023年 | 35篇 |
2022年 | 107篇 |
2021年 | 101篇 |
2020年 | 47篇 |
2019年 | 47篇 |
2018年 | 109篇 |
2017年 | 106篇 |
2016年 | 149篇 |
2015年 | 92篇 |
2014年 | 140篇 |
2013年 | 238篇 |
2012年 | 178篇 |
2011年 | 181篇 |
2010年 | 128篇 |
2009年 | 110篇 |
2008年 | 159篇 |
2007年 | 122篇 |
2006年 | 133篇 |
2005年 | 97篇 |
2004年 | 76篇 |
2003年 | 52篇 |
2002年 | 40篇 |
2001年 | 20篇 |
2000年 | 9篇 |
1999年 | 15篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1979年 | 2篇 |
1966年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1959年 | 2篇 |
1956年 | 2篇 |
1953年 | 2篇 |
1928年 | 2篇 |
排序方式: 共有2590条查询结果,搜索用时 15 毫秒
391.
Bruno G. Lages Beatriz G. Fleury Ana M. C. Hovell Claudia M. Rezende Angelo C. Pinto Joel C. Creed 《Marine Biology》2012,159(7):1551-1559
Competition for space changes species’ distributions and community organization on tropical rocky shores, and the presence of secondary metabolites in the tissues of non-indigenous species may aid them in establishing and expanding their range through negative competitive interactions. The aim of this study was to describe the range of chemical substances produced by the non-indigenous cup corals Tubastraea coccinea and T. tagusensis and to test whether they varied in the field when the corals were placed in proximity to two local competitors. Cholest-5-en-3β-ol and 9-octadecanoic acid were two common secondary metabolites found in the tissues of Tubastraea. In the competition interaction experiment, necrosis was detected on the tissues of the coral Mussismilia hispida, and this species induced variation in sterol, alkaloid, and fatty acid production in Tubastraea tissues. In contrast, a sponge overgrew Tubastraea colonies. These results indicate that chemical defense may contribute to the ability of these non-indigenous corals to invade native communities. 相似文献
392.
393.
Gianluigi Di Paola Pietro Patrizio Ciro Aucelli Guido Benassai Javier Iglesias Germán Rodríguez Carmen Maria Rosskopf 《Journal of Coastal Conservation》2018,22(5):1001-1015
The Coastal Vulnerability and Exposure Degree (CVED) of the Gran Canaria Island and the coastal risk of Playa de Las Canteras (Las Palmas de G.C.) have been assessed by means of a GIS analysis. The evaluation of coastal vulnerability (H) has been performed by using two different levels of analysis: the first one regarding the entire Island (Coastal Vulnerability Index method - CVI), the second one regarding specifically Las Canteras Beach, selected for its socio-economic importance (Coastal Vulnerability Assessment method - CVA). The application of the CVI method, based on geologic-geomorphologic and meteomarine data easily available, has allowed the regional scale assessment of coastal vulnerability (H) along the Gran Canaria coastline and, therefore, the individuation of more critical coast stretches deserving further analysis. The application of the CVA method, based on more specific morphologic-sedimentary beach features that allow to consider both the beach retreat due to storm surge and the coastal inundation due to run-up on the beach, has provided a large scale detail on the coastal vulnerability of Las Canteras Beach. Socio-economic and damage indexes have been determined for the 15 coastal municipalities included in the study area and, by means of the resulting matrix product, the degree of exposure (Ex) along the Gran Canaria coast has been assessed. Finally, the combination of coastal vulnerability and exposure levels has allowed to obtain the Coastal Vulnerability and Exposure Degree (CVED) for the entire Island and the risk levels that characterize specifically Las Canteras Beach. Major results in terms of CVED highlight prevailing low vulnerability and exposure levels along the western coast, and overall high vulnerability and exposure levels along the eastern coast, from Las Palmas de G.C. to San Bartolomé de Tirajana. The focus made on Playa de Las Canteras has allowed to identify the areas characterized by medium and high risk levels that represent approximately one third (940 m) of the entire beach and are located in its central part. The used two-level analysis approach has proved its efficiency by highlighting the degree of coastal vulnerability along the study coast and, especially, more critical coast stretches (CVI method) such as the Playa de Las Canteras that can be successfully analysed with the CVA approach allowing for a large-scale assessment of risk aspects, essential for a correct definition of priority management strategies. Results obtained with the present study, along with the awareness of the increasing phenomena of coastal erosion and marine flooding arising on the mid-long term due to the effects of global climate change, highlight the need for the competent public administrations of Gran Canaria to develop a strategic approach to coastal management and sustainable development that considers as a whole socio-economic values and natural resources, coastal vulnerability and exposure degree, and risk aspects. 相似文献
394.
Sophie Quérouil Luís Freitas Irma Cascão Filipe Alves Ana Dinis Joana R. Almeida Rui Prieto Silvia Borràs José A. Matos Diogo Mendonça Ricardo S. Santos 《Marine Biology》2010,157(11):2567-2580
Several cetacean species exhibit fine-scale population structure despite their high dispersal capacities and the apparent continuity of the marine environment. In dolphins, most studies have focused on coastal areas and continental margins, and they revealed differentiated populations within relatively small geographic areas, sometimes in conjunction with a specialisation for different habitats (ecotypes). We analysed the population genetic structure of short-beaked common dolphins (Delphinus delphis) and Atlantic spotted dolphins (Stenella frontalis) in the Azores and Madeira, the two most isolated archipelagos of the North Atlantic. The archipelago of the Azores is divided into three groups of islands and stands 900 km away from Madeira. It is not known whether individuals migrate between groups of islands and archipelagos, nor whether distinct ecotypes are present. These questions were investigated by genetic analyses of 343 biopsy samples collected on free-ranging dolphins. The analyses consisted in sequencing part of the mitochondrial hyper-variable region, screening up to 14 microsatellite loci, and molecular sexing. Results did not unravel any population structure at the scale of the study area. Lack of differentiation matches expectations for spotted dolphins, which are transient in both archipelagos, but not for common dolphins, which are present year-round in the Azores and potentially resident. Absence of genetic structure over hundreds and even thousands of kilometres implies the existence of gene flow over much larger distances than usually documented in small delphinids, which could be achieved through individual movements. This finding indicates that population structure in oceanic habitat differs from that observed in coastal habitat. 相似文献
395.
Michael Tobler Dennis Hasselquist Henrik G. Smith Maria I. Sandell 《Behavioral ecology and sociobiology》2010,64(5):717-727
Hormone-mediated maternal effects play an important role in the formation of a differentiated phenotype. They have been shown
to influence a wide array of offspring traits, both early in life and in adulthood. One important offspring trait that is
under the influence of maternal androgens is the immune system. In birds, a growing number of studies show that yolk androgens
modulate immune function during the chick stage. However, there is a lack of knowledge regarding long-term effects of prenatal
androgens on offspring immunity. In this study, we therefore investigated the influence of prenatal testosterone (T) on several
measures of immunity in fledgling and adult zebra finches (Taeniopygia guttata). Cell-mediated immune response (towards phytohaemagglutinin, PHA) of fledglings hatching from control eggs was negatively
related to brood size, whereas there was no such association for fledglings hatching from eggs with experimentally elevated
T levels (T fledglings). Male control fledglings showed reduced mass gain compared to female control fledglings within 24 h
after the PHA injection. This pattern was reversed in T fledglings. Total antibody levels in fledglings were not affected
by egg treatment. Neither cell-mediated immunity nor total antibody levels in sexually mature zebra finches were influenced
by egg treatment. However, there was an immuno-enhancing effect of elevated egg T on both primary and secondary humoral immune
responses toward diphtheria and tetanus antigens in ca 5 and 7 month old zebra finches. In addition, the covariation between
different immune components differed between T and control offspring, suggesting that egg treatment may have altered the potential
trade-offs between different parts of the immune system. Our results suggest that prenatal androgens could be an important
factor contributing to individual variation in immune function even in adulthood. 相似文献
396.
Caio F. Gromboni George L. Donati Wladiana O. Matos Eduardo F. A. Neves Ana Rita A. Nogueira Joaquim A. Nóbrega 《Environmental Chemistry Letters》2010,8(1):73-77
Efficiency of metabisulfite and a commercial steel wool as reducing agents in the removal of Cr(VI) from wastewaters was evaluated.
Chromium(VI) was converted to Cr(III), precipitated with NaOH, and removed by filtration. A reduction of more than 1.0 × 105 and 4.0 × 105 fold in total Cr and the Cr(VI) concentrations, respectively, was observed by employing steel wool masses as low as 0.4420 g
to 30-mL solutions of wastewater. Chromium(III) hydroxide obtained after the treatment was recycled and used as marker in
cattle nutrition studies. The liquid residue obtained after the treatment was reused as precipitation agent replacing NaOH. 相似文献
397.
Magnago Rachel Faverzani de Alcântara Braglia Thiago de Aguiar Ana Carolina Baungarten Polyana Mendonça Bruno Afonso Büchele Silva Heloisa Regina Turatti Egert Paola Girotto Edivandro Júnior Américo Cruz Parma Gabriel Oscar Cremona 《Journal of Material Cycles and Waste Management》2021,23(3):1126-1140
Journal of Material Cycles and Waste Management - This article aims to study the mechanical strength and fire resistance of polyurethane/cement (PuCem) composites containing glass sludge and sludge... 相似文献
398.
Girotto Francesca Lavagnolo Maria Cristina Acar Gulgun Piazza Laura 《Journal of Material Cycles and Waste Management》2021,23(1):416-422
Journal of Material Cycles and Waste Management - The effect of ultrasound pre-treatment (for 5, 15, and 30 min) on tomato pomace methane yield was evaluated. With respect to the control... 相似文献
399.
Jerzy Słowikowski Maria Konarska 《International journal of occupational safety and ergonomics》2013,19(4):369-377
The study aimed at verifying a hypothesis that supporting a visual signal of regulation deviation with an auditory one could improve the quality of regulation; the operator would have better information on machine operation. A special simulator was applied to follow-up tracking with a manual lever which controlled vertical movements of a cursor on a monitor screen. Simultaneously with visual information on screen, the operator was provided with an auditory deviation signal of pre-determined characteristics. 33 young males underwent the test. It was found that supporting a visual signal with an auditory one resulted in an improvement in the regulation quality by 5-6%, which proved synergy between those signals. The results may be used in designing tele- and servo-mechanisms, especially for remote control machinery, e.g., inspection robots or micromanipulators controlled by operators in a follow-up system. 相似文献
400.
Roman Cieślak Maria Widerszal-Bazyl Aleksandra Łuszczyńska-Cieślak 《International journal of occupational safety and ergonomics》2013,19(2):257-292
The study concerns the moderating role of two variables—hardiness and social support—in the relation between job stressors and well-being. It was checked if there is a connection between hardiness and social support, and if these variables are directly related to the level of well-being. It was also hypothesized that hardiness and social support buffer the negative influence of stressors on well-being. The fact that social support and well-being are multidimensional variables was taken into account.The cross-sectional study was conducted on a group of 200 women employed as office workers. The results showed that hardiness correlates with the indexes of emotional support as well as practical support coming from supervisors. The connection, however, was not strong. Hardiness and social support were directly connected with the level of well-being. Interaction of these two independent variables played a marginal role. As far as the buffering role of these variables was concerned, the results have shown that hardiness did not play a buffering role and social support did to a limited degree only.The results of the study proved that it is justifiable to treat social support and well-being as multidimensional variables. 相似文献