全文获取类型
收费全文 | 23914篇 |
免费 | 170篇 |
国内免费 | 125篇 |
专业分类
安全科学 | 489篇 |
废物处理 | 1393篇 |
环保管理 | 3457篇 |
综合类 | 2496篇 |
基础理论 | 6867篇 |
环境理论 | 8篇 |
污染及防治 | 5281篇 |
评价与监测 | 1959篇 |
社会与环境 | 2175篇 |
灾害及防治 | 84篇 |
出版年
2022年 | 125篇 |
2021年 | 104篇 |
2020年 | 88篇 |
2019年 | 110篇 |
2018年 | 1730篇 |
2017年 | 1659篇 |
2016年 | 1516篇 |
2015年 | 360篇 |
2014年 | 321篇 |
2013年 | 1194篇 |
2012年 | 891篇 |
2011年 | 2005篇 |
2010年 | 1282篇 |
2009年 | 1177篇 |
2008年 | 1607篇 |
2007年 | 2027篇 |
2006年 | 560篇 |
2005年 | 570篇 |
2004年 | 489篇 |
2003年 | 636篇 |
2002年 | 607篇 |
2001年 | 583篇 |
2000年 | 425篇 |
1999年 | 254篇 |
1998年 | 223篇 |
1997年 | 176篇 |
1996年 | 202篇 |
1995年 | 220篇 |
1994年 | 189篇 |
1993年 | 152篇 |
1992年 | 169篇 |
1991年 | 159篇 |
1990年 | 168篇 |
1989年 | 162篇 |
1988年 | 134篇 |
1987年 | 117篇 |
1986年 | 101篇 |
1985年 | 124篇 |
1984年 | 136篇 |
1983年 | 129篇 |
1982年 | 127篇 |
1981年 | 120篇 |
1980年 | 86篇 |
1979年 | 99篇 |
1978年 | 69篇 |
1977年 | 85篇 |
1976年 | 60篇 |
1975年 | 67篇 |
1974年 | 62篇 |
1973年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 443 毫秒
451.
The capability of a cost-effective and a small size decentralized pilot wastewater treatment plant (WWTP) to remove enteric viruses such as rotavirus, norovirus genogroup I (GGI), norovirus genogroup II (GGII), Hepatitis E virus (HEV), and adenovirus was studied. This pilot plant is an integrated hybrid anaerobic/aerobic setup which consisted of anaerobic sludge blanket (UASB), biological aerated filter (BAF), and inclined plate settler (IPS). Both the UASB and BAF are packed with a non-woven polyester fabric (NWPF). Results indicated that the overall log10 reductions of enteric viruses’ genome copies through the whole system were 3.1 ± 1, 3.3 ± 0.5, and 2.6 ± 0.9 log10 for rotavirus, norovirus GGI, and adenovirus, respectively. Reduction efficiency for both norovirus GGII and HEV after the different treatment steps could not be calculated because there were no significant numbers of positive samples for both viruses. The overall reduction of rotavirus infectious units through the whole system was 2.2 ± 0.8 log10 reduction which is very close to the overall log10 reduction of adenovirus infectious units through the whole system which was 2.1 ± 0.8 log10 reduction. There was no considerable difference in the removal efficiency for different rotavirus G and P types. Adenovirus 41 was the only type detected in the all positive samples. Although the pilot WWTP investigated is cost effective, has a small footprint, does not need a long distance network pipes, and easy to operate, its efficiency to remove enteric viruses is comparable with the conventional centralized WWTPs. 相似文献
452.
Animal territories that differ in the availability of food resources will require (all other things being equal) different levels of effort for successful reproduction. As a consequence, breeding performance may become most strongly dependent on factors that affect individual foraging where resources are poor. We investigated potential links between foraging behaviour, reproductive performance and morphology in a goshawk Accipiter gentilis population, which experienced markedly different resource levels in two different parts of the study area (rabbit-rich vs. rabbit-poor areas). Our analyses revealed (1) that rabbit abundance positively affected male reproductive output; (2) that age, size and rabbit abundance (during winter) positively affected different components of female reproductive output; (3) that foraging movements were inversely affected by rabbit abundance for both sexes (for females, this may mainly have reflected poor provisioning by males in the rabbit-poor area); (4) that younger breeders (both in males and females) tended to move over larger distances than older individuals (which may have reflected both a lack of hunting experience and mate searching); and (5) that male body size (wing length) showed some covariation with resource conditions (suggesting possible adaptations to hunting agile avian prey in the rabbit-poor area). Although we are unable to establish firm causal relationships with our observational data set, our results provide an example of how territory quality (here, food abundance) and individual features (here, age and morphology) may combine to shape a predator's foraging behaviour and, ultimately, its breeding performance. 相似文献
453.
This work was conducted to determine the practicability of using a new adsorbent 4-ethyl thiosemicarbazide intercalated,organophilic calcined hydrotalcite(ETSC-OHTC) for the removal of uranium(U(VI)),and thorium(Th(IV)) from water and wastewater.The FTIR analysis helped in realizing the involvement of nitrogen and sulphur atoms of ETSC in binding the metal ions through complex formation.Parameters like adsorbent dosage,solution pH,initial metal ions concentration,contact time and ionic strength,that influence adsorption phenomenon,were studied.The optimum pH for maximum adsorption of U(VI) and Th(IV) was found to be in the range 4.0-6.0.The contact time required for reaching equilibrium was 4 hr.The pseudo second-order kinetic model was the best fit to represent the kinetic data.Analysis of the equilibrium adsorption data using Langmuir,Freundlich and Sips models showed that the Freundlich model was well suited to describe the metal ions adsorption.The K F values were 25.43 and 29.11mg/g for U(VI) and Th(IV),respectively,at 30°C.The adsorbent can be regenerated effectively from U(VI) and Th(IV) loaded ones using 0.01mol/L HCl.The new adsorbent was quite stable for many cycles,without much reduction in its adsorption capacity towards the metals. 相似文献
454.
A. Hast T. Ekholm I. Savolainen 《Mitigation and Adaptation Strategies for Global Change》2013,18(5):637-658
The European Union (EU) has set a target to reduce its greenhouse gas (GHG) emissions at least 10 % below the 2005 levels by 2020 in the non-Emission Trading Sector (non-ETS). As part of this, each Member State has a binding national emission limitation target for the non-ETS sector. Finland’s target, examined as a case study in this paper, is to reduce emissions at least 16 % below 2005 levels by 2020. The objective of this study is to find cost optimal mitigation portfolios that meet Finland’s reduction target and to analyze the risks of not attaining the emission target or exceeding the assumed costs. The question was addressed with a stochastic optimization model, Stochastic Optimization of non-ETS Emissions (SONETS) selecting separate mitigation measures that meet the target on expectation. The results show that optimal portfolios include relatively high uncertainty both in costs and achieved reductions. The prices of crude oil and diesel, and the abatement cost of reducing hydrofluorocarbon (HFC) emissions seem to account for the majority of uncertainty regarding total costs. The baseline predictions for various non-ETS subsectors (such as transport and agriculture) were found to have the greatest contribution to the uncertainty of attaining emission target. The results also show that some abatement actions are chosen in nearly all efficient portfolios, while other actions are seldom chosen. For example replacing oil burners in the end of technical life time or recovery of methane (CH4) from waste are often chosen whereas ban of landfilling of organic waste is chosen extremely seldom. It also seems that the results are somewhat sensitive to the inclusion or exclusion of the interdependencies of mitigation measures. 相似文献
455.
Andréia Dalla Vecchia Mariana Kluge Joseane V. dos Santos da Silva Juliana Comerlato Manoela T. Rodrigues Juliane D. Fleck Roger B. da Luz Thais F. Teixeira Paulo M. Roehe Roberta Capalonga Ana Beatriz Oliveira Fernando R. Spilki 《Food and environmental virology》2013,5(1):41-45
Torque teno virus (TTV) was surveyed in tap water collected in schools from three municipalities located in the south of Brazil. TTV genomes were found in 11.7 % (4/34) of the samples. TTV DNA was detected in 10.5 % (2/19) of the samples collected at the city of Caxias do Sul and in 25 % (2/8) of the samples from Pelotas. Those cities have a low rate of sewage treatment. All samples from Santa Cruz do Sul, which has nearly 92 % of its sewage treated, were negative. These results suggest that the amount of sewage treated may have an effect on the detection rates of TTV DNA in drinking water in a given urban area, showing a mild negative correlation (r = ?0.76), when comparing the percentage of sewage treatment to the detection of TTV genomes. The detection rate of TTV was also compared with Escherichia coli, showing a strong correlation (r = 0.97), indicating that TTV may be a suitable marker of fecal contamination. 相似文献
456.
Maria Rönnqvist Thedi Ziegler Carl-Henrik von Bonsdorff Leena Maunula 《Food and environmental virology》2012,4(1):26-33
Recent events have shown that humans may become infected with some pathogenic avian influenza A viruses (AIV). Since soil
and water, including lakes, rivers, and seashores, may be contaminated by AIV excreted by birds, effective methods are needed
for monitoring water for emerging viruses. Combining water filtration with molecular methods such as PCR is a fast and effective
way for detecting viruses. The objective of this study was to apply a convenient method for the detection of AIV in natural
water samples. Distilled water and lake, river, and seawater were artificially contaminated with AIV (H5N3) and passed through
a filter system. AIV was detected from filter membrane by real-time RT-PCR. The performance of Zetapor, SMWP, and Sartobind
D5F membranes in recovering influenza viruses was first evaluated using contaminated distilled water. SWMP, which gave the
highest virus recoveries, was then compared with a pre-filter combined GF/F filter membrane in a trial using natural water
samples. In this study, the cellulose membrane SMWP was found to be practical for recovery of AIVs in water. Viral yields
varied between 62.1 and 65.9% in distilled water and between 1 and 16.7% in natural water samples. The borosilicate glass
membrane GF/F combined with pre-filter was also feasible in filtering natural water samples with viral yields from 1.98 to
7.33%. The methods described can be used for monitoring fresh and seawater samples for the presence of AIV and to determine
the source of AIV transmission in an outbreak situation. 相似文献
457.
Sara Romani Seyed Reza Mohebbi Seyed Masoud Hosseini Pedram Azimzadeh Mohsen Vahedi Faramarz Derakhshan Mohammad Reza Zali 《Food and environmental virology》2012,4(1):1-5
Noroviruses are one of important agents that cause acute viral gastroenteritis worldwide. These viruses are belonging to Caliciviridae
family and are genetically diverse. To date, there is no valuable data about prevalence of norovirus infection and the dominant
genogroup/genotype among Iranian population. The objective of this study was to determine the frequency of norovirus infection
in Iranian patients with gastroenteritis referred to three hospitals of Tehran and to specify the dominant genogroup/genotype
of this virus among our study population. A total of 293 patients with acute gastroenteritis were included in the study. Detection
of norovirus was performed using RT-PCR method and confirmed by direct sequencing with specific designed primers for capsid
region of norovirus genome. Phylogenetic analysis was performed using the neighbor-joining method. Norovirus strains identified
in our study were subsequently categorized according to previously defined genogroup/genotypes. Of these, norovirus GII was
dominant genogroup. Sixty-five percent (17 of 26) of positive samples were determined as GII and 35% (9 of 26) were determined
as GI, respectively, in 2008–2009. And among 8 sequenced strains of genogroup II the most frequent genotype was GII.3. The
results of this study indicated that norovirus must be considered as one of the infectious causes of acute gastroenteritis
among Iranian population. We also found that GII.3 is more prevalent in our study population. To the best of our knowledge
there is limited data about the role of noroviruses in children and adults’ acute gastroenteritis among Iranian patients and
this prevalence and genotyping report of norovirus infection could be remarkable for further studies. 相似文献
458.
A framework for analyzing climate change adaptations as actions 总被引:1,自引:0,他引:1
Klaus Eisenack Rebecca Stecker 《Mitigation and Adaptation Strategies for Global Change》2012,17(3):243-260
Developing generalized theories about adaptation to climate change requires common concepts to map different adaptation situations.
The paper aims to contribute to this endeavor by presenting a novel framework that conceptualizes adaptations to climate change
as actions. The framework is intended to systematically analyze the actor relations involved in adaptations and the barriers
to their implementation. By combining established scientific action theories with terminology from the Intergovernmental Panel
on Climate Change (IPCC) in an innovative way, it can be used to clarify the notion of adaptation used in adaptation assessments.
The framework’s potential is illustrated by a case study on cooling water management in the river Rhine catchment and by the
elucidation of some prominent concepts in adaptation research. We show that by framing adaptations as actions, the purpose
of adaptations and how they tend to connect up in means-ends-chains becomes crucial. Actors can take different functional
roles as exposure unit, operator and receptor of adaptation. A mismatch of these roles can lead to barriers to adaptation,
of which we deduce four types: complex actor relations, missing operators, missing means and unemployed means. The case study
yields a complex bundle of adaptations, and shows that the potential barriers involved are quite diverse. There is thus no
blueprint solution. Although we identify entry points for adaptation, the analysis leads to a skeptical conclusion for adapting
cooling water management in the whole Rhine catchment. 相似文献
459.
Ellen M. Douglas Paul H. Kirshen Michael Paolisso Chris Watson Jack Wiggin Ashley Enrici Matthias Ruth 《Mitigation and Adaptation Strategies for Global Change》2012,17(5):537-562
We explored the possible future impacts of increased coastal flooding due to sea level rise and the potential adaptation responses
of two urban, environmental justice communities in the metropolitan Boston area of Massachusetts. East Boston is predominantly
a residential area with some industrial and commercial activities, particularly along the coastal fringe. Everett, a city
to the north of Boston, has a diversified industrial and commercial base. While these two communities have similar socioeconomic
characteristics, they differ substantially in the extent to which residents would be impacted by increased coastal flooding.
In East Boston, a large portion of residents would be flooded, while in Everett, it is the commercial/industrial districts
that are primarily vulnerable. Through a series of workshops with residents in each community, we found that the target populations
do not have an adaptation perspective or knowledge of any resources that could assist them in this challenge. Furthermore,
they do not feel included in the planning processes within their communities. However, a common incentive for both communities
was an intense commitment to their communities and an eagerness to learn more and become actively engaged in decisions regarding
climate change adaptation. The lessons that can be applied to other studies include 1) images are powerful tools in communicating
concepts, 2) understanding existing cultural knowledge and values in adaptation planning is essential to the planning process
and 3) engaging local residents at the beginning of the process can create important educational opportunities and develop
trust and consensus that is necessary for moving from concept to implementation. 相似文献
460.
Makino Yamada Yamanoshita Masahiro Amano 《Mitigation and Adaptation Strategies for Global Change》2012,17(4):425-440
It has been recognized that the involvement of local community is essential to ensure the sustainability of A/R CDM (afforestation/reforestation
clean development mechanism) project. This study verifies if the risks of non-permanence and leakage are addressed in a registered
small scale A/R CDM project in Vietnam. Workshops, interviews, and a questionnaire survey of local villagers revealed that
the project has caused a shortage of land for conventional activities such as grazing, fuel wood collection and shifting cultivation,
and consequently posed the risks of project non-permanence and leakage. It is suggested that participation of all stakeholders
in the community to the A/R CDM project beyond existing land tenure and adequate carbon benefit sharing according to the level
of contribution to the project are required to reduce the risk of non permanence. To ensure the participation, the community
should have capability such as consensus building and collective action. Leakage would be minimized if the community has alternative
measures to the conventional activities before starting the project. We argue that it is necessary to first develop a community’s
capabilities in the readiness phase of any A/R CDM project in order to reduce the risks for the project sustainability, and
that new sources of funding are needed for this purpose. 相似文献