全文获取类型
收费全文 | 10980篇 |
免费 | 119篇 |
国内免费 | 336篇 |
专业分类
安全科学 | 89篇 |
废物处理 | 833篇 |
环保管理 | 1312篇 |
综合类 | 1610篇 |
基础理论 | 3392篇 |
污染及防治 | 2060篇 |
评价与监测 | 1091篇 |
社会与环境 | 999篇 |
灾害及防治 | 49篇 |
出版年
2024年 | 8篇 |
2023年 | 35篇 |
2022年 | 91篇 |
2021年 | 72篇 |
2020年 | 83篇 |
2019年 | 60篇 |
2018年 | 1514篇 |
2017年 | 1422篇 |
2016年 | 1275篇 |
2015年 | 196篇 |
2014年 | 118篇 |
2013年 | 115篇 |
2012年 | 551篇 |
2011年 | 1433篇 |
2010年 | 769篇 |
2009年 | 682篇 |
2008年 | 946篇 |
2007年 | 1297篇 |
2006年 | 62篇 |
2005年 | 66篇 |
2004年 | 84篇 |
2003年 | 114篇 |
2002年 | 156篇 |
2001年 | 70篇 |
2000年 | 43篇 |
1999年 | 19篇 |
1998年 | 23篇 |
1997年 | 13篇 |
1996年 | 14篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1935年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
Hua Shen Larry W. Robertson Gabriele Ludewig 《Environmental science and pollution research international》2016,23(3):2108-2118
Paraoxonase 1 (PON1), an antioxidant enzyme, is believed to play a critical role in many diseases, including cancer. PCBs are widespread environmental contaminants known to induce oxidative stress and cancer and to produce changes in gene expression of various pro-oxidant and antioxidant enzymes. Thus, it appeared of interest to explore whether PCBs may modulate the activity and/or gene expression of PON1 as well. In this study, we compared the effects of dioxin-like and non-dioxin-like PCBs and of various aryl hydrocarbon receptor (AhR) ligands on PON1 regulation and activity in male and female Sprague-Dawley rats. Our results demonstrate that (i) the non-dioxin-like PCB154, PCB155, and PCB184 significantly reduced liver and serum PON1 activities, but only in male rats; (ii) the non-dioxin-like PCB153, the most abundant PCB in many matrices, did not affect PON1 messenger RNA (mRNA) level in the liver but significantly decreased serum PON1 activity in male rats; (iii) PCB126, an AhR ligand and dioxin-like PCB, increased both PON1 activities and gene expression; and (iv) even though three tested AhR ligands induced CYP1A in several tissues to a similar extent, they displayed differential effects on the three PONs and AhR, i.e., PCB126 was an efficacious inducer of PON1, PON2, PON3, and AhR in the liver, while 3-methylcholantrene induced liver AhR and lung PON3, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most potent AhR agonist, increased only PON3 in the lung, at the doses and exposure times used in these studies. These results show that PCBs may have an effect on the antioxidant protection by paraoxonases in exposed populations and that regulation of gene expression through AhR is highly diverse. 相似文献
902.
Jabiol Jérémy Chauvet Eric Guérold François Bouquerel Jonathan Usseglio-Polatera Philippe Artigas Joan Margoum Christelle Le Dréau Matthieu Moreira Aurélie Mazzella Nicolas Gouy Véronique 《Environmental science and pollution research international》2022,29(20):29296-29313
Environmental Science and Pollution Research - Freshwater contamination by pesticides in agricultural landscapes is of increasing concern worldwide, with strong pesticide impacts on biodiversity,... 相似文献
903.
L. Mao Che T. Le Campion-Alsumard N. Boury-Esnault C. Payri S. Golubic C. Bézac 《Marine Biology》1996,126(3):509-519
The composition, distribution and infestation sequence of organisms that destroy the commercially valuable shells of the black oyster Pinctada margaritifera var. cumingii Jameson, 1901 were studied. Three ecologically different groups of boring (euendolithic) organisms were identified: (1) phototrophic boring microorganisms (cyanobacteria, Hyella caespitosa, Hyella sp., Mastigocoleus testarum, Plectonema terebrans, and green algae, Phaeophila dendroides, Ostreobium quekettii); (2) heterotrophic boring microorganisms (fungi, Ostracoblabe implexa); (3) filter-feeding boring organisms (sponges, Cliona margaritiferae, C. vastifica). The phototrophic endoliths dominate the external pristmatic region of the shell, whereas the valuable interior nacreous region is attacked mainly by heterotrophs. Boring patterns reflect in part the shape and behaviour of the organisms and in part the structural properties of the shell, and inflict different types of damage. Infestation starts with microbial borers, which prepare the conditions for later invasion by more damaging clionid sponges. The infestation begins always at the apex, the oldest part of the shells, from which the periostracum is often removed by natural attrition or by cleaning procedure. The rate of bioerosion in 1 yr-old hatchery shells is 36 times higher than in natural populations. 相似文献
904.
Distribution and availability of potentially toxic metals in soil in central area of Belgrade,Serbia 总被引:1,自引:0,他引:1
Rabia Ahmed Ghariani Ivan Gržetić Mališa Antić Snežana Nikolić Mandić 《Environmental Chemistry Letters》2010,8(3):261-269
Belgrade, capital city of Serbia, has over 1,600,000 inhabitants and over 400,000 vehicles trafficking every day on its streets.
The investigation of soil pollution was performed by sequential extraction analysis to investigate the availability of potentially
toxic metals (Zn, Cd, Pb, Co, Ni, Cu, Cr and Mn) under different oxidation and pH conditions. All investigated metals were
mainly extracted from soils with neutral or acidic extractants. Serious pollution was observed along roads and streets with
high traffic frequency, but Pb and Ni pollution was the highest since their concentrations exceed both soil Serbian standard
and Canadian guidance values and is characteristic for all investigated sites. Cd, Cu, Cr and Zn concentrations are moderately
high since they are between Canadian guideline and Serbian standard. 相似文献
905.
Ignacio J. Moncho-Esteve Frederik Folke Manuel García-Villalba Guillermo Palau-Salvador 《Environmental Fluid Mechanics》2017,17(4):695-714
This paper presents large eddy simulation of turbulent flow in a meandering open channel with smooth wall and rectangular cross-section. The Reynolds number based on the channel height is 40,000 and the aspect ratio of the cross-section is 4.48. The depth-averaged mean stream-wise velocity agree well to experimental measurements. In this specific case, two interacting cells are formed that swap from one bend to the other. Transport and mixing of a pollutant is analysed using three different positions of release, e.g. on the inner bank, on the outer bank and on the centre of the cross section. The obtained depth-average mean concentration profiles are reasonably consistent with available experimental data. The role of the secondary motions in the mixing processes is the main focus of the discussion. It is found that the mixing when the scalar is released on the centre of the cross-section is stronger and faster than the mixing of the scalar released on the sides. When the position of release is close to a bank side, the mixing is weaker and a clear concentration of scalar close to the corresponding side-wall can be observed in both cases. 相似文献
906.
Vinod Kumar Yata Bhupesh Chandra Tiwari Irfan Ahmad 《Environmental Chemistry Letters》2018,16(1):79-84
High population rise and climate changes are increasing issues of agricultural production and food safety. Nanotechnology is finding revolutionary applications to improve agricultural and food systems, notably for better crop production and food preservation. Here we review research, industrial and patent trends of nanoscience in food and agriculture. In a literature survey, we found 44.6% publications in the nano-food research area during the years 2013–2015 and 59.09% publications in the nano-agriculture research area during 2012–2015. USA is leading in the development of nanotechnology firms with a maximum share of 75.5% of the total firms, followed by Germany and France with 8.10 and 4.74%, respectively. USA is leading in the nano-food research with 22 granted patents, whereas China is placed first in nano-agriculture research with 28 granted patents during assessment years 2011–2015. Nano-food research focused mainly on nano-food packaging with 76.84% contributions, whereas in nano-agriculture research, focus has been on nano-fertilizers with 90% contributions. Germany, France, Korea, Italy, Czech Republic, Slovenia and Slovak republic have more than 20% of dedicated nanotechnology firms. A growth of about 45% in nano-food patents has been observed for USA during 2011–2015, and China is leading in the nano-agriculture patents with an increase of 60.7% during 2012–2015. 相似文献
907.
We present a new system for microscopic multicolour variable chlorophyll fluorescence imaging of aquatic phototrophs. The
system is compact and portable and enables microscopic imaging of photosynthetic performance of individual cells and chloroplasts
using different combinations of blue, green, red or white light. Automated sequential exposure of microscopic samples to the
three excitation colours enables subsequent deconvolution of the resulting fluorescence signals and colour marking of cells
with different photopigmentation, i.e., cyanobacteria, green algae, red algae and diatoms. The photosynthetic activity in
complex mixtures of phototrophs and natural samples can thus be assigned to different types of phototrophs, which can be quantified
simultaneously. Here, we describe the composition and performance of the new imaging system and present applications with
both natural phytoplankton and microalgal culture samples. 相似文献
908.
We test the hypothesis that echolocation behavior can be used to find the border between bat habitats. Assuming that bats
react to background targets in “edge space” but not in “open space”, we determined the border between these two habitat types
for commuting individuals of the parti-colored bat Vespertilio murinus. We recorded sequences of bats’ echolocation signals while they flew parallel to the walls of large buildings and to the
ground and determined the signals’ average bandwidth, duration, and pulse interval. These parameters varied systematically
with the estimated horizontal and vertical distances between the bats and the background. A distinct effect of horizontal
distance to the background on echolocation behavior was found for horizontal distances of less than 6 m, thus indicating the
border between edge and open space. Only a few bats flew at vertical distances below 5 m. However, enough passages at vertical
distances of 5 m and above indicated that the vertical border is somewhere below a distance of 5 m. Within edge space, V. murinus reacted to the background by reducing signal duration, increasing bandwidth at closer distances, and often emitting one signal
per wing beat. In open space, signal parameters did not vary as a function of distance to the background. There, V. murinus emitted the longest signals with the narrowest bandwidth and often made one or two wing beats without emitting a pulse. With
our data we support with statistical methods the hypothesis that echolocation behavior reveals the border between the habitat
types “edge” and “open space”. 相似文献
909.
Summary. We report field and laboratory evidence indicating that the defensive compounds secreted by the millipedes Amplinus bitumidus (Diplopoda: Polydesmida) and Anadenobolus putealis (Diplopoda: Spirobolida) attract the carrion scarab Canthon morsei (Scarabaeidae: Scarabaeinae). In a Mexican tropical rain forest, C. morsei was mostly caught in pitfall traps baited with the carcasses of both millipede species. Only a few beetles were attracted
to fish carrion. Experimental evidence indicates that C. morsei is attracted to freshly dead millipedes. Benzaldehyde and HCN were identified from Amplinus bitumidus; but 2-methyl-1,4-benzoquinone (toluquinone) and 2-methoxy- 3-methyl-1,4-benzoquinone from Anadenobolus putealis. Benzaldehyde attracted significantly more C. morsei individuals than fish meat, or millipedes of both species did after rinsing in hexane. This is the first report of Polydesmida
attracting dung beetles. 相似文献
910.
Architecture, Engineering, Construction, Operation and Ownership (AECOO) team up in a multi-disciplinary collaborative system to create buildings and infrastructure. The participating disciplines have reached a state in which traditional methods and forms of input data introduce entropy that compromises sustainable construction in larger projects. It became difficult to reach planned optimum project duration and costs this way. New approaches based on the systematic digitalization of the building lifecycle, from design to demolition, can solve the problem by involving the concepts of building information modeling (BIM) systems and big data. Previous research on BIM and big data only studied the potential for construction performance. In addition to extending research into systems’ thinking and technical sustainability of big visual data, this paper extends our previous work in the area by introducing a new conceptual and technical framework for sustainable management of construction site big visual data. 相似文献