全文获取类型
收费全文 | 10199篇 |
免费 | 4298篇 |
国内免费 | 26529篇 |
专业分类
安全科学 | 1035篇 |
废物处理 | 396篇 |
环保管理 | 973篇 |
综合类 | 28832篇 |
基础理论 | 2341篇 |
环境理论 | 1篇 |
污染及防治 | 5607篇 |
评价与监测 | 1490篇 |
社会与环境 | 107篇 |
灾害及防治 | 244篇 |
出版年
2023年 | 17篇 |
2022年 | 33篇 |
2021年 | 38篇 |
2020年 | 602篇 |
2019年 | 1882篇 |
2018年 | 2069篇 |
2017年 | 2044篇 |
2016年 | 1807篇 |
2015年 | 2226篇 |
2014年 | 2859篇 |
2013年 | 3051篇 |
2012年 | 2950篇 |
2011年 | 2461篇 |
2010年 | 2252篇 |
2009年 | 2247篇 |
2008年 | 1888篇 |
2007年 | 1928篇 |
2006年 | 1375篇 |
2005年 | 1064篇 |
2004年 | 976篇 |
2003年 | 756篇 |
2002年 | 615篇 |
2001年 | 636篇 |
2000年 | 717篇 |
1999年 | 610篇 |
1998年 | 459篇 |
1997年 | 435篇 |
1996年 | 466篇 |
1995年 | 426篇 |
1994年 | 273篇 |
1993年 | 213篇 |
1992年 | 276篇 |
1991年 | 278篇 |
1990年 | 237篇 |
1989年 | 206篇 |
1988年 | 152篇 |
1987年 | 72篇 |
1986年 | 81篇 |
1985年 | 61篇 |
1984年 | 61篇 |
1983年 | 47篇 |
1982年 | 55篇 |
1981年 | 44篇 |
1980年 | 10篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1976年 | 6篇 |
1972年 | 11篇 |
1971年 | 11篇 |
1969年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Aliphatic and polycyclic aromatic hydrocarbons in sediments of Kaohsiung Harbour and adjacent coast, Taiwan 总被引:2,自引:0,他引:2
Surficial sediment samples collected from Kaohsiung Harbour and its nearby coast were analyzed for aliphatic hydrocarbons and parent polycyclic aromatic hydrocarbons (PAHs). According to our results, the average total concentrations of n-alkanes (n-C12 to C35) and aromatics (15 PAHs) were 4.33 µg g–1 dry weight (ranged 0.46–22.60) and 0.59 µg g–1 dry weight (ranged 0.09–1.75), respectively. The highest concentrations of aliphatic and aromatic hydrocarbons were recorded in stations near the estuaries of Qianzhen River and Love River, respectively. Aliphatic hydrocarbons in the samples indicate that there has been significant non-petrogenic, possibly terrestrial, contribution in the sediment of the open coast of Kaohsiung Harbour and that there has been dominant contribution from petrogenic sources in the sediment of the inner harbour. PAHs, detected in the samples, however, indicated a higher pyrolytic contribution in open-coast samples and a higher petrogenic contribution in the inner harbour. Overall, sediment concentrations of total alkanes in this study were comparable to those found in Victoria Harbour, Hong Kong and are higher than those found in Xiamen Harbour, China. Concentrations of total PAHs in inner Kaohsiung Harbour sediments were relatively lower than those found in Victoria Harbour, Hong Kong and Xiamen Harbour, China, but comparable to those found in Hsin-ta Harbour, Taiwan and Incheon Harbour, Korea. In comparison with several effect-based sediment quality guidelines, most PAH concentrations found in samples taken from inner harbour stations exceeded the Threshold Effect Level of Florida indicating a slight possibility of adverse effects. 相似文献
112.
In order to investigate the characteristic of optical properties of Asian dust particles, the atmospheric aerosol vertical profile was measured with the multi-wavelength LIDAR system, at the Gosan super site (33 degrees 17'N, 126 degrees 10'E) in Jeju Island, Korea, during the ACE-Asia intensive observation period, 11 March-4 May 2001. An air mass backward trajectory analysis, using Hysplit-4, was carried out to track the aerosol plume, with high mass loading, from the Chinese desert regions during the period of Asian dust storm events. Vertical atmospheric aerosol profiles on three major Asian dust storm event days, 22 March and 13 and 26 April 2001, have been analyzed. The LIDAR-derived aerosol optical depth values were compared with those measured by a collocated sunphotometer. 相似文献
113.
The radiative properties of atmospheric aerosols are determined by their masses, chemical characteristics, and optical properties, such as aerosol optical depth (AOD), Åstrom;ngström parameter (α) and single scattering albedo (SSA). In particular, the aerosol optical properties determine the surface temperature perturbation that may give some information in understanding regional atmospheric radiative forcing. To understand the radiative forcing and regional source of an aerosol, the present study focused on the analysis of the aerosol optical properties based on two different observations in the spring season, during the special Asian dust storm period. The Korean Global Atmosphere Watch Observatory (KGAWO), at Anmyeon Island, and the ACE-Asia super-site, at Gosan, Jeju Island, have measured radiations and aerosols since 2000. The sites are located in the mid-west and south of the Korean peninsula, which are strongly affected by the Asian dust coming from China every spring. The aerosol optical properties, measured by ground-based sun and sky radiometers, over both sites were analyzed to gain an understanding of the radiation and climate properties.The probability distributions of the aerosol optical depths were rather narrow, with a modal value of approximately 0.38 at both sites during 2001 and 2002. The Ångström parameter frequency distributions showed two peaks at Anmyeon GAW, but only one peak at the Jeju ACE-Asia super site. One peak, around 0.63, characterizes the situation of a day having Asian dust, the second peak, around 1.13, corresponded to the relatively dust-free cases. The correlation between the aerosol optical depth and the Ångström exponents resulted in a wide range of the Ångström parameter, α, over a wide range of optical depths at Anmyeon, whereas a narrow range of α, with moderate to low values for the AOD at Jeju. Under dust free conditions the single scattering albedo (SSA) decreased with wavelength, while in the presence of Asian dust,the SSA either stayed neutral, or increased slightly with wavelength at Anmyeon, and showed higher value than Jeju. The change in the surface temperature was highly correlated with increases in the aerosol optical depth at Anmyeon to a greater extent than at Jeju. 相似文献
114.
Thomas G. Hallam Eric T. Funasaki Konstadia Lika Hooi Ling Lee 《Environmental Modeling and Assessment》1997,2(1-2):1-6
The relationships between the dynamics of environmentally and chemically stressed populations and indicators of the effects of the stressor are explored in a model framework. The physiologically structured population, represented by a system of McKendrick–von Foerster hyperbolic partial differential equations, includes the dynamics of numerous individuals distinguished by ecotype. Chemical uptake of nonpolar narcotics is modeled by first order kinetics. Classical methodologies, frequency analysis and phase space reconstruction, are explored in a search for indicators of magnitude of stress. When these techniques proved generally unsuccessful for the objective of indicator selection in our model setting, summary statistics, as related to bifurcation diagrams, were constructed and appear more useful as indicators. It is concluded that physiological structures generally lead to more feasible measurable indicators of magnitude of stress than do specifics of population dynamics. 相似文献
115.
116.
利用植物生态学常规方法进行了荒漠植被种群生物量和数量特证调查,以植物为监测对象,并就群落地上部分生物量,Shannon-Wiener多样性指数,群落均匀度,生态优势度等指标探讨了在荒漠生态环境监测和评价中的具体应用。 相似文献
117.
Kenneth F. Hedden Lee A. Mulkey William A. Tucker 《Environmental monitoring and assessment》1982,2(1-2):57-69
A potentially important exposure route for humans is the ingestion of chemicals via drinking water. If comprehensive exposure assessments are to be completed for either existing or proposed new chemicals and cost effective control strategies developed, then a quantitative understanding of multimedia transport and fate of specific chemical pollutants must be achieved. Mathematical models provide a powerful framework into which quantitative relationships may be placed to provide guidance in reaching water quality goals. Existing, state-of-the-art media-specific toxic organic transport and fate models for atmospheric (DiDOT), land surface (NPS) and surface water processes (EXAMS) and potable water treatment (WTP) have been linked to demonstrate the technical feasibility of such an approach. Limited application and sensitivity testing of this linked modeling system has shown that the impact of various source loadings and control strategies on drinking water quality can be estimated. 相似文献
118.
119.
东南大陆的地质构造模型,具有欧亚大陆边缘向洋增生的独特形式。除外来地体之外,或以扩张、地幔上涌,洋壳向大陆地壳转化,并不断向洋增生;或是大陆分裂,地幔柱——热点物质不断注入变薄和破裂了的地壳,形成区域性新的生长构造层,构造岩浆地质体表现为有独特属性的“A型”花岗岩和流纹岩链。这些高DI值的富硅富碱富钠质岩石,出现在欧亚大陆边缘的重力梯度带上。裂解带的地壳结构模式是上地壳存在着重力不稳定的硅铝低速带;中地壳有洋——陆过渡型地壳的“类裂谷型”结构,P波速度为6.3~6.4km/s的中间壳层;在下地壳下部有速度为7.0~7.4km/s的壳——幔混合型高速层;随着“异常”的上地幔的形成,有大范围的热活动和壳——幔边界穹窿,穹窿的地盖比正常区为为薄。由于化学库和化学边界层的横向不连续,可划分出古老基底和后期地质发展史完全迥异的两个亚板块;和以壳层(或幔层)断裂为边界特点的八个地体;一个以分裂为主,并具热点径迹的最新生长构造层的扩张——裂解构造岩浆地体。 相似文献
120.