全文获取类型
收费全文 | 11239篇 |
免费 | 105篇 |
国内免费 | 282篇 |
专业分类
安全科学 | 228篇 |
废物处理 | 553篇 |
环保管理 | 1367篇 |
综合类 | 1756篇 |
基础理论 | 3130篇 |
环境理论 | 1篇 |
污染及防治 | 2607篇 |
评价与监测 | 809篇 |
社会与环境 | 1124篇 |
灾害及防治 | 51篇 |
出版年
2023年 | 64篇 |
2022年 | 133篇 |
2021年 | 112篇 |
2020年 | 73篇 |
2019年 | 103篇 |
2018年 | 263篇 |
2017年 | 274篇 |
2016年 | 401篇 |
2015年 | 218篇 |
2014年 | 278篇 |
2013年 | 738篇 |
2012年 | 693篇 |
2011年 | 601篇 |
2010年 | 343篇 |
2009年 | 389篇 |
2008年 | 463篇 |
2007年 | 481篇 |
2006年 | 396篇 |
2005年 | 691篇 |
2004年 | 821篇 |
2003年 | 689篇 |
2002年 | 328篇 |
2001年 | 384篇 |
2000年 | 244篇 |
1999年 | 150篇 |
1998年 | 97篇 |
1997年 | 102篇 |
1996年 | 114篇 |
1995年 | 140篇 |
1994年 | 112篇 |
1993年 | 91篇 |
1992年 | 100篇 |
1991年 | 101篇 |
1990年 | 91篇 |
1989年 | 82篇 |
1988年 | 75篇 |
1987年 | 77篇 |
1986年 | 54篇 |
1985年 | 69篇 |
1984年 | 69篇 |
1983年 | 64篇 |
1982年 | 62篇 |
1981年 | 65篇 |
1980年 | 47篇 |
1979年 | 51篇 |
1978年 | 40篇 |
1977年 | 42篇 |
1976年 | 38篇 |
1973年 | 45篇 |
1972年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
A Barba M A Camara S Navarro Garcia C Sanchez-Fresneda N Lopez de Hierro A Acebes 《Journal of environmental science and health. Part. B》1991,26(3):323-332
Residues of Bromopropylate were determine in artichokes, strawberries and beans after foliar spray of acaricide at two rates. The rates used were 1 g/l formulated product (normal recommended) and 1.5 g/l. The residue levels of bromopropylate in the three crops after 14 days were lower than 0.7 ppm and did not exceed the Maximum Residual Level (MRL) recommended by FAO. In the artichokes and strawberries, the total concentration of residues decreased by 50% of the initial level after 2-3 days. Only trace levels of the bromopropylate residues (less than 0.01 ppm) were detected in the "hearts" of the artichokes. Bromopropylate residues in the green beans were also less than 0.8 ppm after the first day of foliar spraying. The kinetic of degradation occurred in two different steps. In the first step (4-6 days) the dissipation of bromopropylate was faster whereas in the second step (7-14 days) the loss of residues was much slower. 相似文献
52.
Body (thorax and prosoma) weight, shell growth, and Zn, Cu, Fe, Mn and Ca levels were measured in artificially settled Elminius modestus over a 14-month period following transfer to high, mid and low tide positions in the uncontaminated Menai Strait and two mid tide sites within a Zn and Cu polluted bay on the North West coast of Anglesey. Barnacles showed higher mortality and slower growth at the upper shore position than at any other site. There was no evidence of Zn and Cu regulation by the bodies or shells, and both seemed to reflect environmental levels. Body metal levels were lowest in early winter and the highest second year values were found in January (Zn), March (Cu, Fe) or May (Ca). Higher shore barnacles contained larger concentrations of Zn than mid or low tide animals. Differences in feeding activity and the amount of testes may account for these variations. Reciprocal transplants between polluted and 'clean' sites indicate that body Cu and Zn accumulation and loss was very rapid. Spatial and temporal changes in shell metal levels closely mirror that of the body. 相似文献
53.
Laboratory and Field Assessment of Arsenic Testing Field Kits in Bangladesh and West Bengal, India 总被引:2,自引:0,他引:2
High concentrations of arsenic in ground waters in West Bengal and Bangladeshhave become a major cause for concern in recent years. Given the enormity and the severity of the problemof arsenic poisoning, a task of evaluating the commercially available arsenic detection field kits for their capabilities was undertaken. In the light of the findings, generic specificationswere recommended which could form the basis forindigenous manufacture of these kits in the arsenic affected countries. This article presents the results of the laboratory and fieldevaluation conducted in Bangladesh and West Bengalof five arsenic testing field kits. The salient features of the kits, their merits and limitationshave been brought out. Based on the criteria of kitdesign, quality of chemicals used, colourcomparator charts, detection range, time required for analysis, cost etc., a comparative ranking ofthe kits has been made to facilitate the choice of the kit to meet specific requirements. 相似文献
54.
Stoichev T Rodriguez Martin-Doimeadios RC Amouroux D Molenat N Donard OF 《Journal of environmental monitoring : JEM》2002,4(4):517-521
The concentration levels of mercury (Hg) species in natural water samples are usually low. Consequently, accurate analysis with low detection limits is still a major problem. In this work, a method was applied for the simultaneous direct determination of dissolved mercury species in water samples by on-line hydride generation (HG), cryogenic trapping (CT), gas chromatography (GC) and detection by atomic fluorescence spectrometry (AFS). The suitability of the method for real samples with different organic matter and chloride contents was evaluated by recovery experiments in synthetic and natural spiked water samples. The HG method was compared with other current available methods for mercury analysis with respect to the different fraction of mercury analysed, i.e. 'reactive', 'reducible' or total. HG derivatization and SnCl2 reduction (with and without previous oxidation with BrCl) were applied to synthetic and natural (spiked and non-spiked) water samples. The influence of chloride and dissolved organic matter concentrations was studied. The results suggest that the HG procedure is suitable for the simultaneous determination of Hg2+ and MeHg+ in surface water samples. Inorganic mercury analysed by HG (i.e. reducible) is close to the total inorganic mercury. 相似文献
55.
Pietrantonio M Calace N Petronio BM Pietroletti M 《Journal of environmental monitoring : JEM》2003,5(3):451-454
An approach based on the number of extractions performed over time was applied to study the time necessary to attain equilibrium conditions between the different chemical forms present in two natural soils laboratory-loaded with heavy metals (Cu(II), Pb(II), Zn(II)). The influence of some soil parameters, such as pH value, cation exchange capacity and organic matter content, on the equilibrium time was evidenced both by the different nature of the soils and by the treatment of soils with paper mill sludge. Equilibrium conditions were determined by studying the metal partitioning in the soil on a case by case basis. The behaviour of the three metals was not the same, and the conditions of equilibrium among the different chemical forms were the result of the amount of heavy metals added as well as of the nature of the soil. 相似文献
56.
Kristina?D.?RothleyEmail author Charlene?Rae 《Environmental Modeling and Assessment》2005,10(2):107-113
In this paper we apply graph theory in a reserve selection exercise to explore the tradeoffs between maintaining connectivity and minimizing the total area of a protected area network. Rather than focus on a single organism, we used a multi-species approach and looked at the tradeoff curves for organisms with varying dispersal abilities. We first generated the tradeoff curves using a graph-based metric to determine the importance of individual patches for maintaining connectivity. We then performed an analogous set of analyses using patch size as a surrogate measure of importance. 相似文献
57.
G. L. Sia C. N. Ong S. E. Chia H. Y. Ong W. H. Phoon K. T. Tan 《Environmental monitoring and assessment》1991,19(1-3):401-411
This study was conducted to evaluate the usefulness of various biological parameters for monitoring of workers exposed to methyl ethyl ketone (MEK). Fifty male workers from a large magnetic videotape factory participated in this study. Personal air samples were collected using 3M organic vapor monitors and analysed for MEK by gas chromatography with flame ionisation detector (FID). 10 mL of urine; blood (1 mL) and exhaled air were also collected at the end of an 8-hour workshift. The headspace GC method was applied for measurement of urinary and blood MEK. MEK in expired air was analysed directly by using a GC/FID.The correlation coefficients (r) between environmental MEK and all other biological parameters measured show significant positive relationships. The r for environmental MEK and urine MEK was 0.84; for blood 0.73 and for breath 0.64. The correlation coefficients between blood and urine was 0.72; blood and breath was 0.88 and urine and breath 0.60. These findings suggest that measurements of unmetabolised MEK in blood, exhaled air and urine can be used for biological monitoring of MEK exposure. Nevertheless, laboratory methodological assessment is in favour of measuring urinary MEK as it is non-invasive and does not have to be analysed immediately after collection. 相似文献
58.
Virendra Misra Shri Dhar Pandey P. N. Viswanathan 《Environmental monitoring and assessment》2000,61(2):231-237
Effect of various concentrations of humic acid (0.2 to 1%) on thebioavailability of -HCH in vegetative clones of theaquatic fern Marsilea minuta was studied in a staticexperimental bioassay system on different photoperiods. Additionof humic acid showed the reduction in the bioavailability of-HCH in all the photoperiods (72 hr light to 144 hrlight) at the interval of 16 hr light (L) and 8 hr dark (D) inboth aerial and submerged portion as compared to controlindicating its protective role in toxicity. 相似文献
59.
60.
The Prairie Adaptation Research Collaborative (PARC) has implemented an Internet Map Server (IMS) at the PARC web site (www.parc.ca) to 1) disseminate the geo-referenced results of PARC sponsored research on climate change impacts and adaptation, and 2) address data, information and knowledge management within the PARC network of researchers and partners. PARC facilitates interdisciplinary research on adaptation to the impacts of climate change in the Canadian Prairie Provinces. The web site is intended as a platform for sharing information and encouraging discussion of climate change impacts and adaptation. The IMS enables scientists and stakeholders to apply simple climate change scenarios to geo-referenced biophysical and social data, and dynamically create maps that display the geographic distribution of potential impacts of climate change. With a limited capacity for spatial analysis, most geo-processing and the climate impact modeling is done offline within a GIS environment. The IMS will serve the output from climate impact models, such that the model results can be customized by the web site user and be most readily applied to the planning and analysis of adaptation strategies. 相似文献