全文获取类型
收费全文 | 14348篇 |
免费 | 177篇 |
国内免费 | 108篇 |
专业分类
安全科学 | 452篇 |
废物处理 | 545篇 |
环保管理 | 2394篇 |
综合类 | 2352篇 |
基础理论 | 3697篇 |
环境理论 | 9篇 |
污染及防治 | 3488篇 |
评价与监测 | 878篇 |
社会与环境 | 700篇 |
灾害及防治 | 118篇 |
出版年
2023年 | 74篇 |
2022年 | 122篇 |
2021年 | 123篇 |
2020年 | 95篇 |
2019年 | 125篇 |
2018年 | 209篇 |
2017年 | 184篇 |
2016年 | 277篇 |
2015年 | 240篇 |
2014年 | 317篇 |
2013年 | 1156篇 |
2012年 | 451篇 |
2011年 | 618篇 |
2010年 | 506篇 |
2009年 | 591篇 |
2008年 | 666篇 |
2007年 | 646篇 |
2006年 | 565篇 |
2005年 | 507篇 |
2004年 | 426篇 |
2003年 | 451篇 |
2002年 | 429篇 |
2001年 | 524篇 |
2000年 | 391篇 |
1999年 | 232篇 |
1998年 | 173篇 |
1997年 | 182篇 |
1996年 | 197篇 |
1995年 | 235篇 |
1994年 | 220篇 |
1993年 | 200篇 |
1992年 | 164篇 |
1991年 | 182篇 |
1990年 | 184篇 |
1989年 | 172篇 |
1988年 | 136篇 |
1987年 | 129篇 |
1986年 | 137篇 |
1985年 | 118篇 |
1984年 | 130篇 |
1983年 | 132篇 |
1982年 | 149篇 |
1981年 | 140篇 |
1980年 | 127篇 |
1979年 | 132篇 |
1978年 | 94篇 |
1977年 | 86篇 |
1975年 | 81篇 |
1973年 | 77篇 |
1972年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
981.
Thomas PJ Mineau P Shore RF Champoux L Martin PA Wilson LK Fitzgerald G Elliott JE 《Environment international》2011,37(5):914-920
Second-generation anticoagulant rodenticides (SGARs) are widely used to control rodent pests but exposure and poisonings occur in non-target species, such as birds of prey. Liver residues are often analysed to detect exposure in birds found dead but their use to assess toxicity of SGARs is problematic. We analysed published data on hepatic rodenticide residues and associated symptoms of anticoagulant poisoning from 270 birds of prey using logistic regression to estimate the probability of toxicosis associated with different liver SGAR residues. We also evaluated exposure to SGARs on a national level in Canada by analysing 196 livers from great horned owls (Bubo virginianus) and red-tailed hawks (Buteo jamaicensis) found dead at locations across the country. Analysis of a broader sample of raptor species from Quebec also helped define the taxonomic breadth of contamination. Calculated probability curves suggest significant species differences in sensitivity to SGARs and significant likelihood of toxicosis below previously suggested concentrations of concern (<0.1mg/kg). Analysis of birds from Quebec showed that a broad range of raptor species are exposed to SGARs, indicating that generalised terrestrial food chains could be contaminated in the vicinity of the sampled areas. Of the two species for which we had samples from across Canada, great horned owls are exposed to SGARs to a greater extent than red-tailed hawks and the liver residue levels were also higher. Using our probability estimates of effect, we estimate that a minimum of 11% of the sampled great horned owl population is at risk of being directly killed by SGARs. This is the first time the potential mortality impact of SGARs on a raptor population has been estimated. 相似文献
982.
Al-Jundi J Li WB Abusini M Tschiersch J Hoeschen C Oeh U 《Journal of environmental radioactivity》2011,102(6):574-580
High indoor radon concentrations in Jordan result in internal exposures of the residents due to the inhalation of radon and its short-lived progeny. It is therefore important to quantify the annual effective dose and further the radiation risk to the radon exposure. This study describes the methodology and the biokinetic and dosimetric models used for calculation of the inhalation doses exposed to radon progeny. The regional depositions of aerosol particles in the human respiratory tract were firstly calculated. For the attached progeny, the activity median aerodynamic diameters of 50 nm, 230 nm and 2500 nm were chosen to represent the nucleation, accumulation and coarse modes of the aerosol particles, respectively. For the unattached progeny, the activity median thermodynamic diameter of 1 nm was chosen to represent the free progeny nuclide in the room air. The biokinetic models developed by the International Commission on Radiological Protection (ICRP) were used to calculate the nuclear transformations of radon progeny in the human body, and then the dosimetric model was applied to estimate the organ equivalent doses and the effective doses with the specific effective energies derived from the mathematical anthropomorphic phantoms. The dose conversion coefficient estimated in this study was 15 mSv WLM−1 which was in the range of the values of 6-20 mSv WLM−1 reported by other investigators. Implementing the average indoor radon concentration in Jordan, the annual effective doses were calculated to be 4.1 mSv y−1 and 0.08 mSv y−1 due to the inhalation of radon progeny and radon gas, respectively. The total annual effective dose estimated for Jordanian population was 4.2 mSv y−1. This high annual effective dose calculated by the dosimetric approach using ICRP biokinetic and dosimetric models resulted in an increase of a factor of two in comparison to the value by epidemiological study. This phenomenon was presented by the ICRP in its new published statement on radon. 相似文献
983.
Kurnaz A Kucukomeroglu B Damla N Cevik U 《Journal of environmental radioactivity》2011,102(4):393-399
The activity concentrations and absorbed gamma dose rates due to primordial radionuclides and 137Cs have been ascertained in 222 soil samples in 18 counties of the Trabzon province of Turkey using a HPGe detector. The mean activity concentrations of 238U, 232Th, 40K and 137Cs in soil samples were 41, 35, 437 and 21 Bq kg−1, respectively. Based on the measured concentrations of these radionuclides, the mean absorbed gamma dose in air was calculated as 59 nGy h−1 and hence, the mean annual effective dose due to terrestrial gamma radiation was calculated as 72 μSv y−1. In addition, outdoor in situ gamma dose rate (D) measurements were performed in the same 222 locations using a portable NaI detector and the annual effective dose was calculated to be 66 μSv y−1 from these results. The results presented in this study are compared with other parts of Turkey. Radiological maps of the Trabzon province were composed using the results obtained from the study. 相似文献
984.
Aerial measurement of radioxenon concentration off the west coast of Vancouver Island following the Fukushima reactor accident 总被引:1,自引:0,他引:1
Sinclair LE Seywerd HC Fortin R Carson JM Saull PR Coyle MJ Van Brabant RA Buckle JL Desjardins SM Hall RM 《Journal of environmental radioactivity》2011,102(11):1018-1023
In response to the Fukushima nuclear reactor accident, on March 20th, 2011, Natural Resources Canada conducted aerial radiation surveys over water just off the west coast of Vancouver Island. Dose-rate levels were found to be consistent with background radiation, however a clear signal due to 133Xe was observed. Methods to extract 133Xe count rates from the measured spectra, and to determine the corresponding 133Xe activity concentration, were developed. The measurements indicate that 133Xe concentrations on average lie in the range of 30-70 Bq/m3. 相似文献
985.
Ariamalar Selvakumar Mary Ellen Tuccillo Swarna Muthukrishnan Asim B. Ray 《补救:环境净化治理成本、技术与工艺杂志》2009,19(2):135-142
Several compositions of Fenton's Reagent and hydrogen peroxide alone were used to disinfect combined sewage samples from a wastewater treatment facility. The presettled samples contained suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L, respectively. Disinfection with Fenton's Reagent was carried out at a pH between 5.90 and 6.0 and at a temperature of 25°C. All disinfected samples contained residual oxidants. Under all reaction conditions studied, complete inactivation of E. coli was achieved within one minute of the addition of Fenton's Reagent. Disinfection with hydrogen peroxide alone under similar conditions is incomplete even under much longer contact times. © 2009 Wiley Periodicals, Inc. 相似文献
986.
987.
988.
989.
990.
B. Manos J. Papathanasiou Th. Bournaris K. Voudouris 《Journal of environmental management》2010,91(7):1593-1600
Current international research focuses on topics like sustainable development, regional planning, environmental decision making and implementation, biodiversity conservation plus a number of other relevant issues, especially at times of economic crisis as today. Economic growth and environmental protection can go hand in hand, provided that decision makers develop and use tools and insights targeting in the implementation of successful and robust long term policies. This paper was developed in the framework of a European research project and implements a Multicriteria Mathematical Programming model that optimises the sustainable management of agricultural regions taking in account the available resources (land, labour, capital) and environmental parameters (agrochemicals, water consumption). The model achieves the optimum farm plan in the area combining different criteria to a utility function under a set of constraints and the spatial integration of the vulnerability maps of the regions into the model enables the regional authorities to design policies for the optimal agricultural development and the groundwater protection from the agricultural land uses. Furthermore, the model is used to simulate different scenarios and policies by the local stakeholders, due to changes on different social, economic and environmental parameters. In this way the decision makers can achieve alternative farm plans and agricultural land uses as well as to estimate economic, social and environmental impacts of different policies. The model has been applied to an agricultural region in Northern Greece and proved to be a valuable tool in the implementation of environmental policies and actions, especially in agricultural regions in a delicate balance as the study area. 相似文献