全文获取类型
收费全文 | 975篇 |
免费 | 70篇 |
国内免费 | 320篇 |
专业分类
安全科学 | 76篇 |
废物处理 | 58篇 |
环保管理 | 82篇 |
综合类 | 538篇 |
基础理论 | 205篇 |
污染及防治 | 289篇 |
评价与监测 | 37篇 |
社会与环境 | 37篇 |
灾害及防治 | 43篇 |
出版年
2023年 | 24篇 |
2022年 | 60篇 |
2021年 | 41篇 |
2020年 | 40篇 |
2019年 | 49篇 |
2018年 | 40篇 |
2017年 | 49篇 |
2016年 | 50篇 |
2015年 | 55篇 |
2014年 | 68篇 |
2013年 | 85篇 |
2012年 | 81篇 |
2011年 | 78篇 |
2010年 | 63篇 |
2009年 | 65篇 |
2008年 | 42篇 |
2007年 | 50篇 |
2006年 | 38篇 |
2005年 | 32篇 |
2004年 | 31篇 |
2003年 | 32篇 |
2002年 | 39篇 |
2001年 | 24篇 |
2000年 | 32篇 |
1999年 | 33篇 |
1998年 | 42篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 21篇 |
1994年 | 13篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1977年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有1365条查询结果,搜索用时 15 毫秒
111.
112.
Seasonal variation on size distribution and concentration of PAHs in Guangzhou city, China 总被引:6,自引:0,他引:6
Size distribution aerosol samples were collected at an urban location of Guangzhou in four seasons of 2003-2004 by a MOUDI (Micro-orifice Uniform Deposit Impactor). The particle loading (PM10: 80-397 microg m(-3)) was comparable with some other Asia cities; however, much higher than that of Western Europe and North America. Polycyclic aromatic hydrocarbons (PAHs) were measured by gas chromatography with mass selective detector (GC-MS). Seasonal effects on the size distribution of PAHs are presented. Bimode (accumulation and coarse mode) and unimode (accumulation mode) distributions were observed for low-molecule-weight and high-molecule-weight PAHs. A slight shift to larger particles was found for the accumulation mode in autumn and winter, compared with that of spring and summer. One explanation is that the longer aging process of PAHs in autumn and winter would result in volatilization from finer particles followed by condensation onto coarser particles. Another is there was mixing process of local emission with long-range transported aerosol in autumn and winter. The relative higher value of IcdP/(BghiP+IcdP) and lower value of BghiP/BeP in winter also give evidences to the mixing process. The level of PAHs concentration has been much elevated in recent years. This can be attributed to the fast growth of motor vehicle and energy consumption. 相似文献
113.
唐双娥 《中国环境管理干部学院学报》1999,(4)
通过对1998年长江、嫩江特大洪水的反思,指出了目前森林立法中存在的种种弊端,从而提出了完善我国森林立法的建议。 相似文献
114.
115.
116.
钢结构的抗连续倒塌能力一般取决于其抵抗局部损伤的能力,但这种能力往往取决于许多因素,目前还没有一个稳定可靠的判定方法。基于组件法建模原理将顶底角钢-腹板双角钢节点离散为多个对受力有贡献的基本组件,然后通过集成组件来模拟节点的受力特性,并依此构建了顶底角钢-腹板双角钢半刚性节点梁柱子结构的连续倒塌数值分析模型。结果表明:通过与试验结果比较,节点组件模型能较为准确地反映节点的断裂路径和受力发展过程,同时降低了计算成本。说明组件法在连续倒塌研究中具有重要的理论意义和应用价值,可作为连续倒塌研究的有利工具。 相似文献
117.
Feng Y Shi G Wu J Wang Y Zhu T Dai S Pei Y 《Journal of the Air & Waste Management Association (1995)》2007,57(2):164-171
Particle-associated polycyclic aromatic hydrocarbon (PAH) concentrations were investigated at six sampling sites in the heating (February to March 2001) and nonheating (August to September 2001) periods in an industrial city in Northern China. Thirteen PAHs were measured. The total average concentrations (nanograms per meter cubed) of PAHs ranged between 78.93 and 214.63 during the heating period and from 31.48 to 102.26 in the nonheating period. Benzo(a)pyrene occurred at the highest level at a site near an industrial area but occurred at low concentrations far from the city center and industrial areas. In addition, ambient PAH profiles were studied. The five and six-ring species occurred in high fractions at the sampling site. By diagnostic ratio analysis, the major source at each sampling site in the city was coal combustion in the heating period; in the nonheating period, the major sources were relatively complex. Finally, the similarities among the six regions were assessed by principal component analysis, cluster analysis, and coefficient of divergence. These multivariate statistical analyses produced similar results, which agreed with the results from the diagnostic ratio analysis. 相似文献
118.
Polybrominated diphenyl ethers in house dust in Singapore 总被引:8,自引:0,他引:8
The use of polybrominated diphenyl ethers (PBDEs) as flame retardants in Singapore is not strictly regulated; therefore these compounds can be readily found in furniture, electronic devices, and building materials. This study was the first of its kind to be conducted in Singapore to measure concentrations of PBDEs in house dust. Samples were collected from 31 homes in various locations across the island-state of Singapore, and a total eight PBDEs congeners were measured. PBDEs were detected in all 31 dust samples and the number of BDE congener detected per home ranged between 3 and 8. The most abundant BDE congeners found were BDE 47, 99 and 209, with a median value of 20 ng g(-1) dust, 24 ng g(-1) dust and 1000 ng g(-1) dust, respectively. BDE 209 contributed 88% to the median of all the congeners, and BDE 47 and 99 contributed 1.8% and 3.5%, respectively. Different congener profiles were observed between this and studies conducted elsewhere, which is consistent with the use of different commercial PBDE around the world. No significant correlations between PBDE dust levels and residential characteristics (number of TVs and computers, floor area or flooring material) were observed. The daily intake of PBDEs via the inhalation pathway was estimated. House dust may be regarded as the most important exposure route of PBDEs for children. 相似文献
119.
120.
Although the use of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) has been prohibited in Singapore since 1980, OCPs and PCBs still can be detected in the environment and represent a potential threat to public health. In this study, OCPs and PCBs were measured in house dust samples collected from 31 homes across the island-state of Singapore. Organochlorine pesticides, such as hexachlorocyclohexanes (HCHs), chlordanes and dichlorodiphenyltrichloroethanes (DDTs) were tested, with a range of 相似文献