全文获取类型
收费全文 | 13147篇 |
免费 | 139篇 |
国内免费 | 103篇 |
专业分类
安全科学 | 345篇 |
废物处理 | 681篇 |
环保管理 | 1490篇 |
综合类 | 1551篇 |
基础理论 | 3335篇 |
环境理论 | 8篇 |
污染及防治 | 4016篇 |
评价与监测 | 1019篇 |
社会与环境 | 886篇 |
灾害及防治 | 58篇 |
出版年
2023年 | 83篇 |
2022年 | 187篇 |
2021年 | 216篇 |
2020年 | 116篇 |
2019年 | 130篇 |
2018年 | 270篇 |
2017年 | 268篇 |
2016年 | 415篇 |
2015年 | 261篇 |
2014年 | 436篇 |
2013年 | 1058篇 |
2012年 | 528篇 |
2011年 | 678篇 |
2010年 | 548篇 |
2009年 | 514篇 |
2008年 | 656篇 |
2007年 | 686篇 |
2006年 | 576篇 |
2005年 | 495篇 |
2004年 | 416篇 |
2003年 | 449篇 |
2002年 | 397篇 |
2001年 | 540篇 |
2000年 | 365篇 |
1999年 | 214篇 |
1998年 | 148篇 |
1997年 | 141篇 |
1996年 | 146篇 |
1995年 | 176篇 |
1994年 | 132篇 |
1993年 | 107篇 |
1992年 | 128篇 |
1991年 | 122篇 |
1990年 | 135篇 |
1989年 | 131篇 |
1988年 | 95篇 |
1987年 | 88篇 |
1986年 | 66篇 |
1985年 | 92篇 |
1984年 | 89篇 |
1983年 | 86篇 |
1982年 | 83篇 |
1981年 | 73篇 |
1980年 | 63篇 |
1979年 | 68篇 |
1977年 | 53篇 |
1976年 | 48篇 |
1975年 | 53篇 |
1974年 | 51篇 |
1973年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
611.
612.
Lasun T. Ogundele Oyediran K. Owoade Felix S. Olise Philip K. Hopke 《Environmental monitoring and assessment》2016,188(10):574
To identify the potential sources responsible for the particulate matter emission from secondary iron and steel smelting factory environment, PM2.5 and PM2.5?10 particles were collected using the low-volume air samplers twice a week for a year. The samples were analyzed for the elemental and black carbon content using x-ray fluorescence spectrometer and optical transmissometer, respectively. The average mass concentrations were 216.26, 151.68, and 138. 62 μg/m3 for PM2.5 and 331.36, 190.01, and 184.60 μg/m3 for PM2.5?10 for the production, outside M1 and outside M2 sites, respectively. The same size resolved data set were used as input for the positive matrix factorization (PMF), principal component factor analysis (PCFA), and Unmix (UNMIX) receptor modeling in order to identify the possible sources of particulate matter and their contribution. The PMF resolved four sources with their respective contributions were metal processing (33 %), e-waste (33 %), diesel emission (22 %) and soil (12 %) for PM2.5, and coking (50 %), soil (29 %), metal processing (16 %) and diesel combustion (5 %) for PM2.5?10. PCFA identified soil, metal processing, Pb source, and diesel combustion contributing 45, 41, 9, and 5 %, respectively to PM2.5 while metal processing, soil, coal combustion and open burning contributed 43, 38, 12, and 7 %, respectively to the PM2.5?10. Also, UNMIX identified metal processing, soil, and diesel emission with 43, 42 and 15 % contributions, respectively for the fine fraction, and metal processing (71 %), soil (21 %) and unidentified source (1 %) for the coarse fraction. The study concluded that metal processing and e-waste are the major sources contributing to the fine fraction while coking and soil contributed to the coarse fraction within the factory environment. The application of PMF, PCFA and UNMIX receptor models improved the source identification and apportionment of particulate matter drive in the study area. 相似文献
613.
614.
615.
616.
617.
618.
Victor M. Rodríguez-Moreno Stephen H. Bullock 《Environmental monitoring and assessment》2014,186(2):1009-1021
Remotely sensed imageries were used to analyze the response of desert vegetation to physiographic factors and accumulated precipitation in drier and wetter years within a region of >16,500 km2 sampled with 5,000 random pixels of 30 m. Vegetation development was indexed by the annual maximum values for greenness (SAVI) and canopy water content (NDII). Precipitation was interpolated from the 0.25° grid of the Tropical Rainfall Measurement Mission satellite-based estimates, showing a regional average of ~55 mm in the wetter year. The vegetation indices were only weakly related to total precipitation, often in a negative sense. Terrain factors that most often affected the vegetation indices, in multiple regression models, were Topographic Wetness Index, elevation, and slope gradient; these often had different signs for SAVI and for NDII. Models for NDII on intrusive igneous rocks gave better results than on extrusive igneous rocks. The strongest patterns in vegetation development were the contrast among Pacific coast, Cordillera, and Gulf coast subregions and the generally stronger results for NDII than SAVI. 相似文献
619.
Vít Matějů Simona Vosáhlová Robin Kyclt Tomáš Janoch Gabriela Šedivcová 《Environmental monitoring and assessment》2014,186(2):711-718
Soil-dwelling annelids of the genus Enchytraeus are used in ecotoxicology for testing of chemicals mixed in artificial soil or for testing of wastes and soils of unknown quality. ISO 16387 describes a method for determining the effects of substances or contaminated soils on survival and reproduction of Enchytraeus albidus or of the smaller species Enchytraeus buchholzi or Enchy-traeus crypticus. After the total test duration of 6 (or 4)?weeks, the juveniles hatched in the meantime are counted. There are several possible extraction techniques, which are always followed by counting the juveniles by hand, but none of them seems easy to handle. We proposed a new modification of the worm extraction method using flotation of fixed and stained juveniles followed by taking a photograph. The digital image of the juveniles is evaluated by computer processing. It makes the counting of juveniles much easier and less labor intensive. 相似文献
620.
Vinicius T. Kütter Monica Wallner-Kersanach Silvia M. Sella Ana Luiza S. Albuquerque Bastiaan A. Knoppers Emmanoel V. Silva-Filho 《Environmental monitoring and assessment》2014,186(1):559-573
This long-term study, performed during the years 2003–2005 and 2008–2009, investigated the carbon (C), nitrogen (N), and phosphorus (P) contents of the phyto- and zooplankton communities and the nutrient regime of Cabo Frio Bay, SE Brazil. The information intends to serve as baseline of the plankton C, N, and P stoichiometry for the calibration of biogeochemical and ecological models in support to future findings related to the local and regional phenomena of climatic change. Cabo Frio Bay is a small semienclosed system set adjacent to a region subject to sporadic coastal upwelling. Zooplankton exhibited average annual C, N, and P contents of 11.6?±?6.9 %, 2.8?±?1.8 %, and 0.18?±?0.08 %, and phytoplankton (>20 μm) 6.8?±?6.0 %, 1.6?±?1.5 %, and 0.09?±?0.08 %, respectively. The C/N/P ratios correspond to the lowest already found to date for a marine environment. The low C contents must have been brought about by a predominance of gelatinous zooplankton, like Doliolids/ Salps and also Pteropods. Average annual nutrient concentrations in the water were 0.21?±?0.1 μM for phosphate, 0.08?±?0.1 μM for nitrite, 0.74?±?1.6 μM for nitrate, and 1.27?±?1.1 μM for ammonium. N/P ratios were around 8:1 during the first study period and 12:1 during the second. The plankton C/N/P and N/P nutrient ratios and elemental concentrations suggest that the system was oligotrophic and nitrogen limited. The sporadic intrusions of upwelling waters during the first study period had no marked effect upon the systems metabolism, likely due to dilution effects and the short residence times of water of the bay. 相似文献