全文获取类型
收费全文 | 4713篇 |
免费 | 307篇 |
国内免费 | 1343篇 |
专业分类
安全科学 | 358篇 |
废物处理 | 289篇 |
环保管理 | 466篇 |
综合类 | 2396篇 |
基础理论 | 851篇 |
环境理论 | 1篇 |
污染及防治 | 1301篇 |
评价与监测 | 354篇 |
社会与环境 | 266篇 |
灾害及防治 | 81篇 |
出版年
2024年 | 15篇 |
2023年 | 90篇 |
2022年 | 184篇 |
2021年 | 202篇 |
2020年 | 191篇 |
2019年 | 173篇 |
2018年 | 203篇 |
2017年 | 239篇 |
2016年 | 240篇 |
2015年 | 255篇 |
2014年 | 241篇 |
2013年 | 436篇 |
2012年 | 384篇 |
2011年 | 405篇 |
2010年 | 290篇 |
2009年 | 341篇 |
2008年 | 337篇 |
2007年 | 372篇 |
2006年 | 316篇 |
2005年 | 230篇 |
2004年 | 212篇 |
2003年 | 189篇 |
2002年 | 166篇 |
2001年 | 118篇 |
2000年 | 85篇 |
1999年 | 54篇 |
1998年 | 41篇 |
1997年 | 46篇 |
1996年 | 34篇 |
1995年 | 29篇 |
1994年 | 30篇 |
1993年 | 30篇 |
1992年 | 13篇 |
1991年 | 23篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 10篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1978年 | 6篇 |
1976年 | 5篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1969年 | 5篇 |
排序方式: 共有6363条查询结果,搜索用时 0 毫秒
981.
982.
Oil concentrations in the seawater, seabed sediments, and shoreline sediments were measured from the samples collected 165 days after the Keumdong oil spill accident, which had occurred in Kwangyang Bay of the South Sea, Korea in September 1993. Distribution patterns of the concentrations in the seabed and shoreline sediments have allowed us to hindcast the transport and fate of the spilled oil. Overall, the patterns agree better with the southward (seaward) surface water circulation than with the northward (landward) bottom water circulation over the region. Rapid, initial dispersal of the spilled oil to the south and its subsequent grounding onto the intertidal seabed sediments, as well as onto the shorelines, appear to have made ineffective the subsurface oil transport by the bottom current. 相似文献
983.
运河(杭州段)底质有机质与重金属元素相关性的探讨 总被引:7,自引:0,他引:7
通过对京杭大运河 (杭州段 )底质的监测 ,探讨了底质有机质与 8种重金属元素的相关性 ,并对其成因作出了解释 ,得出了 8种重金属在运河 (杭州段 )底质中易积累的顺序。 相似文献
984.
David Ching‐Fang Shih Chin‐Dee Lee Kin‐Forie Chiou Shi‐Ming Tsai 《Journal of the American Water Resources Association》2000,36(5):1087-1099
ABSTRACT: Water level data at 16 ground water wells and two sea water gauging stations, coupled with barometric measurements in an alluvial plain in the central‐west region of Taiwan, are analyzed using spectral analysis in the time and frequency domains. The semi‐diurnal component from water level station is observed to be the most noticeable signal while the diurnal component is the less distinct signal recorded at the water level stations. Both semidiurnal and diurnal components are coupled with atmospheric pressure measurements. From the atmospheric pressure data, spectral analysis indicates that both the raw and the pressure adjusted water levels are almost in phase and retain the same amplitude in this area. It implies that the effect of pressure variations is not significant for the sea water and ground water level nearby; the astronomical tidal components, as expected, are the main factor causing fluctuation of ocean water and ground water levels in the Choshuihsi alluvial plain. 相似文献
985.
Jason S. Lee Belinda L. Daniels David T. Eberiel Richard E. Farrell 《Journal of Polymers and the Environment》2000,8(2):81-89
Soil retrieval, processing and storage procedures can have a profound effect on soil microorganisms. In particular, changes in soil microbial populations may adversely affect the biological activity of a soil and drastically alter the soil's potential to mineralize added substrates. The effects of cold storage on the biodegradation of a series of test polymers was investigated using two soils—a synthetic soil mix (SM-L8) and a field soil (Bridgehampton silt loam) from Rhode Island (RI-1). Biodegradation tests were conducted using freshly prepared/collected soil and again following storage at 4°C for 3 to 8 months. Prior to each biodegradation test, the soils were incubated at 60% water-holding capacity (WHC) and 25°C to rejuvenate the microbial populations; the soils were incubated for periods of 48 h (freshly collected soil) or 25 days (soils stored at 4°C). Soil microbial populations were assessed by enumerating different segments of the population on agar plates containing different selective media. Mineralization of the test polymers (cellulose, poly-3-hydroxybutyrate, and starch acetate, d.s. 1.5) was monitored using standard respirometric techniques. Our results demonstrated that cold storage had a generally negative effect on the soil microbial populations themselves but that its effect on the capacity of the soil microorganisms to degrade the test polymers varied between soils and polymer type. Whereas cold storage resulted in dramatic shifts in the community structure of the soil microbial populations, substantial restoration of these populations was possible by first conditioning the soils at 60% WHC and ambient temperatures for 25 days. Likewise, although the effects of cold storage on polymer mineralization varied with the test polymer and soil, these effects could be largely offset by including an initial 25-day stabilization period in the test. 相似文献
986.
987.
988.
通过CdO、NiO酸浸反应的热力学和动力学研究 ,得知CdO、NiO二者的浸出条件有较大差异 ,实验确定了废镉镍电池中镉优先浸出的工艺条件 :5 0℃、pH =2的硫酸溶液中浸 5 0min ,在此工艺条件下 ,镉能 10 0 %浸出 ,而镍的浸出率只有 2 5 %。 相似文献
989.
The cytochrome P-450 dependent mixed-function oxygenase (MFO) system ofNereis virens, found in the endoplasmic reticulum of the intestinal epithelium, has similar components and cofactor requirements when compared to other invertebrates. Worms exposed to food containing benzo(a)pyrene or a mixture of polychlorinated biphenyls (Aroclor 1254) had significantly higher MFO activity and cytochrome P-450 content than unexposed ones.N. virens from a site in Porland, Maine, USA, which was heavily contaminated with oil, and nearby clean reference sites were studied. The weight, MFO activity and presence or absence of gametes were determined. The MFO activity in worms from the oil-contaminated site was approximately six times that of worms from the reference sites; worms from the reference areas were six times larger than oil-contaminated worms. Worms from the oil-contaminated area lacked or had undeveloped gametes in spring, summer and fall. In contrast, many of the worms collected from the reference sites at the same times had fully developed gametes. 相似文献
990.
珠江水体表层沉积物中PAHs的含量与来源研究 总被引:3,自引:0,他引:3
沿珠江白鹅潭水域及大学城官州河流域设立6个采样点,利用沉积物捕获器收集沉积物。参照美国EPA8000系列方法及质量保证和质量控制,对各采样点表层沉积物中16种多环芳烃(polycyclic aromatic hydrocarbons,PAHs)进行分析,以阐明珠江广州河段表层沉积物中PAHs的含量和分布特征,并结合特征化合物指数对其来源作初步探讨。珠江广州河段表层沉积物中PAHs总量介于4 787.5~8 665 ng·g^-1,平均值为7 078 ng·g^-1,黄沙码头河涌出口沉积物中总量为最高(8 665 ng·g^-1),芳村码头为最低(4 787.5 ng·g^-1)。16种多环芳烃中菲、荧蒽、芘含量较高,分别占PAHs总量的16.11%、14.47%和17.77%。特征化合物荧蒽/202比值均小于0.5,茚并[1,2,3-cd]芘/276比值均大于0.2,表明珠江广州段表层沉积物中PAHs主要来源于化石燃料的不完全燃烧。 相似文献