全文获取类型
收费全文 | 11306篇 |
免费 | 963篇 |
国内免费 | 2294篇 |
专业分类
安全科学 | 2245篇 |
废物处理 | 273篇 |
环保管理 | 1856篇 |
综合类 | 5864篇 |
基础理论 | 1150篇 |
污染及防治 | 1215篇 |
评价与监测 | 681篇 |
社会与环境 | 781篇 |
灾害及防治 | 498篇 |
出版年
2024年 | 19篇 |
2023年 | 144篇 |
2022年 | 271篇 |
2021年 | 350篇 |
2020年 | 387篇 |
2019年 | 358篇 |
2018年 | 313篇 |
2017年 | 438篇 |
2016年 | 546篇 |
2015年 | 494篇 |
2014年 | 601篇 |
2013年 | 750篇 |
2012年 | 936篇 |
2011年 | 976篇 |
2010年 | 758篇 |
2009年 | 888篇 |
2008年 | 555篇 |
2007年 | 783篇 |
2006年 | 745篇 |
2005年 | 665篇 |
2004年 | 546篇 |
2003年 | 486篇 |
2002年 | 441篇 |
2001年 | 304篇 |
2000年 | 322篇 |
1999年 | 283篇 |
1998年 | 192篇 |
1997年 | 188篇 |
1996年 | 145篇 |
1995年 | 179篇 |
1994年 | 130篇 |
1993年 | 86篇 |
1992年 | 88篇 |
1991年 | 44篇 |
1990年 | 32篇 |
1989年 | 19篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 11篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1972年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
941.
西部地区工业发展的比较优势分析 总被引:1,自引:0,他引:1
西部大开发实施以来,西部地区经济发展迅速,在产业结构升级和优化上取得了较大成绩.对西部地区1997-2006年的相关工业数据进行了分析,从总量、结构以及比较优势等方面加以把握,归纳出西部地区工业发展的几个显著特点以及成因,提出一些对策思路,主要包括:培育国家政策扶持机制,强化科技投入增长的保障机制,建设具有西部特色和优势的区域创新体系,健全金融体系等. 相似文献
942.
943.
944.
在我国新休假制度下,城郊游短线旅游受到越来越多旅游者的青睐。通过问卷调查,采用SPSS分析方法,得出长沙市城郊旅游市场在人口学和市场结构方面的一些特征。在市场分析的基础上,选择长沙市城郊旅游的目标市场,并针对相关问题对城郊旅游开发提出了一些建议,如以创造旅游者体验为核心提升景点价值;针对不同类型的消费者采取差异化的价格,宜采用多样化的促销方式和以直接营销渠道为主。 相似文献
945.
乡村旅游产品提质升级策略探析 总被引:1,自引:0,他引:1
近年来,我国乡村旅游市场发展迅猛,涌现出大批乡村旅游接待点。但由于专业经营管理和市场理念不成熟,我国乡村旅游市场在产品品质、服务质量、经营管理等方面存在诸多问题,需要从乡村旅游产品系统出发,以文化提升、整合提升、体验提升和服务提升策略进行乡村旅游产品提质升级,保障乡村旅游市场的健康发展。 相似文献
946.
公众参与环境决策是一项重要的公众民主权利。我国已经将环境公众参与作为一项重要的环境保护法律制度,但是由于目前我国环保法律制度的不完善,在实施公众参与环境决策机制上存在着诸多问题,本文从法制的角度探讨了公众参与环境决策的理论依据,分析和论证建立适合我国国情的公众参与环境决策制度的主要方式,并提出完善公众参与环境决策制度的建议。 相似文献
947.
Yu-Pin Lin Bai-You Cheng Tsun-Kuo Chang 《Environmental pollution (Barking, Essex : 1987)》2010,158(1):235-244
This study identifies the natural background, anthropogenic background and distribution of contamination caused by heavy metal pollutants in soil in Chunghua County of central Taiwan by using a finite mixture distribution model (FMDM). The probabilities of contaminated area distribution are mapped using single-variable indicator kriging and multiple-variable indicator kriging (MVIK) with the FMDM cut-off values and regulation thresholds for heavy metals. FMDM results indicate that Cr, Cu, Ni and Zn can be individually fitted by a mixture model representing the background and contamination distributions of the four metals in soil. The FMDM cut-off values for contamination caused by the metals are close to the regulation thresholds, except for the cut-off value of Zn. The receiver operating characteristic (ROC) curve validates that indicator kriging and MVIK with FMDM cut-off values can reliably delineate heavy metals contamination, particularly for areas lacking background information and high heavy metal concentrations in soil. 相似文献
948.
Xiaosong Chang Xiaoyun Liu Hao Chen Zhiqun Qiu Jia Cao 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1444-6108
Sewage samples from 4 hospitals, 1 nursery, 1 slaughter house, 1 wastewater treatment plant and 5 source water samples of Chongqing region of Three Gorge Reservoir were analyzed for macrolide, lincosamide, trimethoprim, fluorouinolone, sulfonamide and tetracycline antibiotics by online solid-phase extraction and liquid chromatography-tandem mass spectrometry. Results showed that the concentration of ofloxacin (OFX) in hospital was the highest among all water environments ranged from 1.660 μg/L to 4.240 μg/L and norfloxacin (NOR, 0.136-1.620 μg/L), ciproflaxacin (CIP, ranged from 0.011 μg/L to 0.136 μg/L), trimethoprim (TMP, 0.061-0.174 μg/L) were commonly detected. Removal range of antibiotics in the wastewater treatment plant was 18-100% and the removal ratio of tylosin, oxytetracycline and tetracycline were 100%. Relatively higher removal efficiencies were observed for tylosin (TYL), oxytetracycline (OXY) and tetracycline (TET)(100%), while lower removal efficiencies were observed for Trimethoprim (TMP, 1%), Epi-iso-chlorotetracycline (EICIC, 18%) and Erythromycin-H2O (ERY-H2O, 24%). Antibiotics were removed more efficiently in primary treatment compared with those in secondary treatment. 相似文献
949.
Ruowei Ma 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1354-5700
The study reported in this paper examined the concentrations of nineteen perfluorochemicals (PFCs), including perfluoroalkyl sulfonates, carboxylates, and sulfonamides in samples collected from Hong Kong wastewater treatment plants (WWTPs) and sediments. The study was the first to use an external isolator column to assist in the quantification of PFCs in environmental samples without having to make internal modifications to a liquid chromatography system. Perfluorooctanesulfonate was found to be the dominant PFC pollutant in Hong Kong, and the WWTP sludge was the major sink of PFCs discharged from the urban areas. Compared to discharge influenced by industrial activities, much less perfluorooctanoate was found in waste streams. The significantly lower level of perfluorodecanesulfonate in WWTP sludge reflects the important influence of consumer products on PFC distribution. The dominance of even-chain length perfluoroalkyl carboxylates in all of the WWTP sludge samples investigated further suggests the strong aerobic degradation of fluorotelomer alcohols in WWTPs. 相似文献
950.
Arturo Rodríguez-Blanco Virginie Antoine Emilien Pelletier Jean-François Ghiglione 《Environmental pollution (Barking, Essex : 1987)》2010,158(3):663-1031
The dynamics of total and active microbial communities were studied in seawater microcosms amended with crude or diesel oil at different temperatures (25, 10 and 4 °C) in the presence/absence of organic fertilization (Inipol EAP 22). Total and hydrocarbon-degrading microbes were enumerated by fluorescence microscopy and Most Probable Number (MPN) method, respectively. Total (16S rDNA-based) vs. active (16S rRNA) bacterial community structure was monitored by Capillary-Electrophoresis Single Strand Conformation Polymorphism (CE-SSCP) fingerprinting. Hydrocarbons were analyzed after 12 weeks of incubation by gas chromatography-mass spectrometry. Total and hydrocarbon-degrading microbial counts were highly influenced by fertilization while no important differences were observed between temperatures. Higher biodegradation levels were observed in fertilized microcosms. Temperature and fertilization induced changes in structure of total bacterial communities. However, fertilization showed a more important effect on active bacterial structure. The calculation of Simpson's diversity index showed similar trends among temperatures whereas fertilization reduced diversity index of both total and active bacterial communities. 相似文献