全文获取类型
收费全文 | 3028篇 |
免费 | 110篇 |
国内免费 | 256篇 |
专业分类
安全科学 | 169篇 |
废物处理 | 210篇 |
环保管理 | 269篇 |
综合类 | 801篇 |
基础理论 | 549篇 |
环境理论 | 2篇 |
污染及防治 | 896篇 |
评价与监测 | 273篇 |
社会与环境 | 181篇 |
灾害及防治 | 44篇 |
出版年
2024年 | 5篇 |
2023年 | 51篇 |
2022年 | 134篇 |
2021年 | 146篇 |
2020年 | 102篇 |
2019年 | 97篇 |
2018年 | 131篇 |
2017年 | 146篇 |
2016年 | 170篇 |
2015年 | 130篇 |
2014年 | 161篇 |
2013年 | 298篇 |
2012年 | 215篇 |
2011年 | 228篇 |
2010年 | 170篇 |
2009年 | 155篇 |
2008年 | 177篇 |
2007年 | 149篇 |
2006年 | 154篇 |
2005年 | 133篇 |
2004年 | 99篇 |
2003年 | 80篇 |
2002年 | 66篇 |
2001年 | 27篇 |
2000年 | 15篇 |
1999年 | 19篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1983年 | 2篇 |
1979年 | 2篇 |
1972年 | 2篇 |
1966年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1953年 | 2篇 |
1928年 | 2篇 |
排序方式: 共有3394条查询结果,搜索用时 560 毫秒
71.
目的:了解石油管道储运员工的心理健康现状,建立管道储运员工症状自评量表(SCL-90)的群体常模。方法:运用整群抽样方法和症状自评量表(SCL-90)对5544名中国石化管道储运公司员工进行心理健康状况调查,将SCL-90结果与中国常模比较。结果:本次调查心理健康状况好3947人,占71.2%;心理健康状况良好1299人,占23.4%;心理健康状况一般238人,占4.3%;心理健康状况异常60人,占1.1%;石化管道储运员工在躯体化、焦虑、精神病性、阳性项目数均分显著高于全国常模;人际关系、敌对、偏执和精神病性因子均分男性显著高于女性,恐怖因子均分女性显著高于男性;35岁及以上组的躯体化、强迫、抑郁、焦虑、敌对、恐怖、精神病性以及阳性项目数的因子均分均高于35岁以下组;大专组和高中及以下组各项因子均分均显著高于本科及以上组。结论:管道储运员工心理健康状况低于一般人群。年龄相对较大以及学历相对较低员工的心理健康状况是企业关注的重点。 相似文献
72.
73.
Antonella?De?DonnoEmail author Tiziana?Grassi Francesco?Bagordo Adele?Idolo Francesca?Serio Giovanni?Gabutti 《Food and environmental virology》2012,4(2):81-88
The purpose of this study was to demonstrate that shellfish can be used to detect enteric viruses in marine waters where they
are present at very low concentrations. Aqua-cultured mussels were placed in the sea just off the mouth of a drainage channel
affected by human and animal faecal contamination. Samples were taken from the channel, the sea and the mussels at intervals
over two 4-week periods. The samples were tested to verify the presence of both rotaviruses and E. coli. Rotaviruses were detected by Real Time-PCR, typed by multiplex PCR and subsequently sequenced. E. coli was enumerated in water matrices by a filtering method and in mussels by the MPN method. The presence of E. coli in the examined matrices demonstrates contamination of faecal origin throughout the studied environments. Rotaviruses were
recorded in channel waters, but not in sea water. In both experiments, rotaviruses were detected in mussels 21 and 28 days
after being placed in the sea water off the channel mouth. The use of mussels thus enabled the detection of rotaviruses in
waters where the high dilution rendered direct investigation impossible. This study indicates that mussels can be used in
marine virological surveillance programs. 相似文献
74.
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
75.
利用连续分级提取方法,对天津汉沽海域表层沉积物中P的含量水平、赋存形态、及其生物有效性进行了分析。结果表明:表层沉积物中TP的含量在525.68×10-6~688.39×10-6之间,平均含量约为618.18×10-6,其中86.98%以IP的形式存在;而在IP中,FA-P是其主要的赋存形态,平均约占TP的59.54%;IP含量范围为48.52×10-6~146.72×10-6,平均约占TP的13.02%。P的生物有效性分析结果显示,潜在的生物有效P主要包括Ads-P、Fe-P和OP等3种赋存形态,而天津汉沽海域表层沉积物中潜在的生物有效P含量约为465.87×10-6~609.79×10-6,平均约占沉积物TP的89.14%,表明研究区域内沉积物具有很强的释P潜力。 相似文献
76.
Environmental sustainability in manufacturing is nowadays an urgent and remarkable issue and the main concerns are related to more efficient use of materials and energy.In sheet metal forming processes there is still a lack of knowledge in this field mainly due to the need of a proper modelling of sustainability issues and factors to be taken into account. The aim of this paper is mainly to underline the state of the art from a forming point of view about the sustainability contributions offered in any phase of a product life cycle. Actually, a lack in terms of comprehensive contributions is present in the technical literature, thus, the authors try to give a sort of holistic vision aimed to provide basic guidelines in order to help in identifying the possible solutions with regard to all the phases of a forming product life cycle. The main attention was paid to sheet metal forming technologies. The paper gives an overview of the main topics concerning sheet metal forming problems related to energy and resource efficiency with the aim to stress the principal contributions which may derive from such processes to environmental performances of manufacturing. 相似文献
77.
78.
Lipid regulators have been detected in effluents from sewage treatment plants and surface waters from humans via excretion. This study was designed to assess the ecotoxicity of fibrates, lipid regulating agents. The following compounds were investigated: Bezafibrate, Fenofibrate and Gemfibrozil and their derivatives obtained by solar simulator irradiation. Bioassays were performed on bacteria, algae, rotifers and microcrustaceans to assess acute and chronic toxicity, while SOS Chromotest and Ames test were utilized to detect the genotoxic potential of the investigated compounds. The photoproducts were identified by their physical features and for the first risk evaluation, the environmental impact of parental compounds was calculated by Measured Environmental Concentrations (MEC) using the available data from the literature regarding drug occurrence in the aquatic environment and the Predicted No Effect Concentrations (PNEC) based on our toxicity data. The results showed that acute toxicity was in the order of dozens of mg/L for all the trophic levels utilized in bioassays (bacteria, rotifers, crustaceans). Chronic exposure to these compounds caused inhibition of growth population on rotifers and crustaceans while the algae seemed to be slightly affected by this class of pharmaceuticals. Genotoxic and mutagenic effects were especially found for the Gemfibrozil photoproduct suggesting that also byproducts have to be considered in the environmental risk of drugs. 相似文献
79.
Application of ICP-QMS for the determination of plutonium in environmental samples for safeguards purposes 总被引:1,自引:0,他引:1
Aiming to determine the plutonium amount as well as its isotopic composition, in particular, in swipe samples for safeguards purposes, an analytical method was developed with a plutonium separation step based on extraction chromatography using 2 cm TEVA columns and detection with quadrupole ICP-MS applying an ultra-sonic nebulizer coupled with membrane desolvation system. The method was successfully applied to New Brunswick plutonium certified reference materials as well as to Lawrence Livermore National Laboratory round robin samples, based on the round robin samples provided by the Institute for Reference Materials and Measurements (Belgium), as part of the Regular European Interlaboratory Measurement Evaluation Programme (REIMEP), campaign 16 (isotopic abundances of plutonium in plutonium nitrate samples), with a total plutonium amount between 1 and 0.25 ng per sample. After the introduction of an additional separation step, it was also possible to carry out precise and accurate total plutonium, (240)Pu/(239)Pu, (241)Pu/(239)Pu and (242)Pu/(239)Pu atom ratios determination in sediment sample showing its applicability to environmental samples in general, reaching a detection limit equivalent to 5 mBq(239)Pu kg(-1). 相似文献
80.