全文获取类型
收费全文 | 142篇 |
免费 | 3篇 |
专业分类
测绘学 | 4篇 |
大气科学 | 3篇 |
地球物理 | 67篇 |
地质学 | 28篇 |
海洋学 | 22篇 |
天文学 | 6篇 |
自然地理 | 15篇 |
出版年
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 6篇 |
2012年 | 2篇 |
2011年 | 8篇 |
2010年 | 7篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 14篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1961年 | 2篇 |
排序方式: 共有145条查询结果,搜索用时 31 毫秒
101.
102.
R. J. Law 《Marine pollution bulletin》1978,9(12):321-324
Samples of fish, water and sediment were collected during the Ekofisk ‘Bravo’ blow-out and analysed for specific aliphatic and aromatic hydrocarbons. Analyses showed the presence of petroleum hydrocarbons from the blow-out in some of the water samples, but fish and sediments, collected up to a week after it began, showed no evidence of a contribution from the blow-out. 相似文献
103.
104.
J. Law 《Pure and Applied Geophysics》1961,50(1):102-111
Summary Measurements have been made of the concentration of condensation nuclei, Z, at four heights between the ground and 300 cms in country air close to Cambridge. When the results are averaged over sufficiently long periods a systematic variation of Z with height is found and this variation itself has a diurnal variation. The results imply the production of nuclei in the atmosphere in this region. With the aid of simplifying assumptions, estimates of the rate of production are made for various periods of the day and night. 相似文献
105.
An analysis of soil moisture dynamics using multi-year data from a network of micrometeorological observation sites 总被引:4,自引:0,他引:4
Gretchen R. Miller Dennis D. Baldocchi Beverly E. Law Tilden Meyers 《Advances in water resources》2007
Soil moisture data, obtained from four AmeriFlux sites in the US, were examined using an ecohydrological framework. Sites were selected for the analysis to provide a range of plant functional type, climate, soil particle size distribution, and time series of data spanning a minimum of two growing seasons. Soil moisture trends revealed the importance of measuring water content at several depths throughout the rooting zone; soil moisture at the surface (0–10 cm) was approximately 20–30% less than that at 50–60 cm. A modified soil moisture dynamics model was used to generate soil moisture probability density functions at each site. Model calibration results demonstrated that the commonly used soil matric potential values for finding the vegetation stress point and field content may not be appropriate, particularly for vegetation adapted to a water-controlled environment. Projections of future soil moisture patterns suggest that two of the four sites will become severely stressed by climate change induced alterations to the precipitation regime. 相似文献
106.
107.
Benjamin Horton Michael Bird Thomas Birkland Susan Cowie Ong Jin Eong Andrea Hawkes Gong Wooi Khoon Lisa Law Colin Macgregor Aileen Tan Shau‐Hwai Teh Tiong Sa Zulfigar Yasin 《Singapore journal of tropical geography》2008,29(3):307-324
This paper addresses some of the environmental and socioeconomic dimensions of the 2004 Indian Ocean tsunami on Penang, Malaysia. We aim to offer wide access to unique and perishable data, while at the same time providing insight to ongoing debates about hazards, vulnerability and social capital. Our social survey examines some of the dynamics that shaped the tsunami impact, response and recovery process. While in terms of lives lost Penang may not conform to arguments surrounding vulnerable environments, the recovery process is more marked by social disparities in terms of the ability to access resources. Our physical survey records local topography, flow depth and flow direction, and charts the differential impact of the tsunami. Yet measuring hazards is not a straightforward process, and relies on reflexive methodologies and eyewitness accounts. 相似文献
108.
Tibetan heritage buildings have a high historical and cultural value. They have endured adverse environmental loadings over hundreds of years without significant damage. However, there are few reports on their structural characteristics under normal environmental loadings and their behavior under dynamic loadings. In this research, a typical Tibetan wooden wall-frame building is selected to study its dynamic characteristics. Field measurements of the structure were conducted under environmental excitation to collect acceleration responses. The stochastic subspace identification (SSI) method was adopted to calculate the structural modal parameters and obtain the out-of-plane vibration characteristics of the slab and frames. The results indicated that the wall-frame structure had a lower out-of-plane stiffness and greater in-plane stiffness due to the presence of stone walls. Due to poor identified damping ratio estimates from the SSI method, a method based on the variance upper bound was proposed to complement the existing variance lower bound method for estimating the modal damping ratio to address the significant damping variability obtained from different points and measurements. The feasibility of the proposed method was illustrated with the measured data from the floor slab of the structure. The variance lower and upper bound methods both provided consistent results compared to those from the traditional SSI method. 相似文献
109.
A Bayesian probabilistic approach is presented for the damage detection of multistorey frame structures. In this paper, a Bayesian probabilistic approach is applied to identify multiple damage locations using estimated modal parameters when (1) the measurement data are potentially corrupted with noise, (2) only a small number of degrees of freedom are measured, and (3) a few fundamental modes are estimated. To reduce the potentially intensive computational cost of the proposed method, a branch-and-bound search scheme is proposed and a simplified approach for the modelling of multistorey frame structures is employed. A six-storey shear frame example and two multistorey frame examples, with multiple damage locations, are presented to illustrate the applicability of the proposed approach. © 1997 John Wiley & Sons, Ltd. 相似文献
110.