全文获取类型
收费全文 | 4741篇 |
免费 | 208篇 |
国内免费 | 92篇 |
专业分类
测绘学 | 154篇 |
大气科学 | 516篇 |
地球物理 | 1326篇 |
地质学 | 2069篇 |
海洋学 | 203篇 |
天文学 | 562篇 |
综合类 | 82篇 |
自然地理 | 129篇 |
出版年
2022年 | 42篇 |
2021年 | 76篇 |
2020年 | 61篇 |
2019年 | 38篇 |
2018年 | 162篇 |
2017年 | 153篇 |
2016年 | 229篇 |
2015年 | 159篇 |
2014年 | 245篇 |
2013年 | 294篇 |
2012年 | 247篇 |
2011年 | 179篇 |
2010年 | 233篇 |
2009年 | 241篇 |
2008年 | 179篇 |
2007年 | 136篇 |
2006年 | 115篇 |
2005年 | 114篇 |
2004年 | 89篇 |
2003年 | 73篇 |
2002年 | 81篇 |
2001年 | 87篇 |
2000年 | 77篇 |
1999年 | 74篇 |
1998年 | 97篇 |
1997年 | 62篇 |
1996年 | 77篇 |
1995年 | 60篇 |
1994年 | 64篇 |
1993年 | 47篇 |
1992年 | 35篇 |
1991年 | 36篇 |
1990年 | 38篇 |
1989年 | 41篇 |
1988年 | 27篇 |
1987年 | 41篇 |
1986年 | 34篇 |
1985年 | 36篇 |
1984年 | 44篇 |
1983年 | 55篇 |
1982年 | 42篇 |
1981年 | 35篇 |
1980年 | 38篇 |
1979年 | 44篇 |
1978年 | 42篇 |
1977年 | 38篇 |
1976年 | 28篇 |
1975年 | 44篇 |
1974年 | 38篇 |
1973年 | 40篇 |
排序方式: 共有5041条查询结果,搜索用时 62 毫秒
131.
132.
133.
134.
135.
Martina?S?tteleEmail author Michael?Krautblatter Michael?Bründl Daniel?Straub 《Landslides》2016,13(4):737-750
Warning systems are increasingly applied to reduce damage caused by different magnitudes of rockslides and rockfalls. In an integrated risk-management approach, the optimal risk mitigation strategy is identified by comparing the achieved effectiveness and cost; estimating the reliability of the warning system is the basis for such considerations. Here, we calculate the reliability and effectiveness of the warning system installed in Preonzo prior to a major rockfall in May 2012. “Reliability” is defined as the ability of the warning system to forecast the hazard event and to prevent damage. To be cost-effective, the warning system should forecast an event with a limited number of false alarms to avoid unnecessary costs for intervention measures. The analysis shows that to be reliable, warning systems should be designed as fail-safe constructions. They should incorporate components with low failure probabilities, high redundancy, have low warning thresholds, and additional control systems. In addition, the experts operating the warning system should have limited risk tolerance. In an additional hypothetical probabilistic analysis, we investigate the effect of the risk attitude of the decision makers and of the number of sensors on the probability of detecting the event and initiating a timely evacuation, as well as on the related intervention cost. The analysis demonstrates that quantitative assessments can support the identification of optimal warning system designs and decision criteria. 相似文献
136.
Holger Frey Christian Huggel Yves Bühler Daniel Buis Maria Dulce Burga Walter Choquevilca Felipe Fernandez Javier García Hernández Claudia Giráldez Edwin Loarte Paul Masias Cesar Portocarrero Luis Vicuña Marco Walser 《Landslides》2016,13(6):1493-1507
The town of Santa Teresa (Cusco Region, Peru) has been affected by several large debris-flow events in the recent past, which destroyed parts of the town and resulted in a resettlement of the municipality. Here, we present a risk analysis and a risk management strategy for debris-flows and glacier lake outbursts in the Sacsara catchment. Data scarcity and limited understanding of both physical and social processes impede a full quantitative risk assessment. Therefore, a bottom-up approach is chosen in order to establish an integrated risk management strategy that is robust against uncertainties in the risk analysis. With the Rapid Mass Movement Simulation (RAMMS) model, a reconstruction of a major event from 1998 in the Sacsara catchment is calculated, including a sensitivity analysis for various model parameters. Based on the simulation results, potential future debris-flows scenarios of different magnitudes, including outbursts of two glacier lakes, are modeled for assessing the hazard. For the local communities in the catchment, the hazard assessment is complemented by the analysis of high-resolution satellite imagery and fieldwork. Physical, social, economic, and institutional vulnerability are considered for the vulnerability assessment, and risk is eventually evaluated by crossing the local hazard maps with the vulnerability. Based on this risk analysis, a risk management strategy is developed, consisting of three complementing elements: (i) standardized risk sheets for the communities; (ii) activities with the local population and authorities to increase social and institutional preparedness; and (iii) a simple Early Warning System. By combining scientific, technical, and social aspects, this work is an example of a framework for an integrated risk management strategy in a data scarce, remote mountain catchment in a developing country. 相似文献
137.
The impact of salt on the late Messinian to recent tectonostratigraphic evolution of the Cyprus subduction zone 下载免费PDF全文
Messinian evaporites of locally more than 3‐km thickness occupy the subduction zone between Cyprus and Eratosthenes Seamount. Based on a dense grid of seismic reflection profiles, we report on compressional salt tectonics and its impact on the Late Miocene to Quaternary structural evolution of the Cyprus subduction zone. Results show that evaporites have experienced significant post‐Messinian shortening along the plate boundary. Shortening has initiated allochthonous salt advance between Cyprus and Eratosthenes Seamount, representing an excellent example of salt which efficiently escapes subduction and accretion. Further east, between Eratosthenes Seamount and the Hecataeus Rise, evaporites were compressionally inflated without having advanced across post‐Messinian strata. Such differences in the magnitude of salt tectonic shortening may reflect a predominately north–south oriented post‐Messinian convergence direction, raising the possibility of a later coupling between the motion of Cyprus and Anatolia than previously thought. Along the area bordered by Cyprus and Eratosthenes Seamount a prominent step in the seafloor represents the northern boundary of a controversially debated semi‐circular depression. Coinciding with the southern edge of the salt sheet, this bathymetric feature is suggested to have formed as a consequence of compressional salt inflation and seamount‐directed salt advance. Topographic lows on top of highly deformed evaporites are locally filled by up to 700 m of late Messinian sediments. The uppermost 200 m of these sediments were drilled in the course of ODP Leg 160 and interpreted to represent Lago Mare‐type deposits (Robertson, Tectonophysics, 1998d, 298 , 63‐82). Lago Mare deposits are spatially restricted to the western part of the subduction zone, pinching out towards the east whereas presumably continuing into the Herodotus Basin further west. We suggest a sea level control on late Messinian Lago Mare sedimentation, facilitating sediment delivery into basinal areas whereas inhibiting Lago Mare deposition into the desiccated Levant Basin. Locally, early salt deformation is believed to have provided additional accommodation space for Lago Mare sedimentation, resulting in the presently observed minibasin‐like geometry. 相似文献
138.
139.
140.