全文获取类型
收费全文 | 644篇 |
免费 | 150篇 |
国内免费 | 219篇 |
专业分类
测绘学 | 30篇 |
大气科学 | 355篇 |
地球物理 | 283篇 |
地质学 | 97篇 |
海洋学 | 150篇 |
天文学 | 22篇 |
综合类 | 42篇 |
自然地理 | 34篇 |
出版年
2024年 | 6篇 |
2023年 | 4篇 |
2022年 | 19篇 |
2021年 | 21篇 |
2020年 | 25篇 |
2019年 | 22篇 |
2018年 | 25篇 |
2017年 | 38篇 |
2016年 | 33篇 |
2015年 | 39篇 |
2014年 | 49篇 |
2013年 | 56篇 |
2012年 | 41篇 |
2011年 | 43篇 |
2010年 | 43篇 |
2009年 | 36篇 |
2008年 | 36篇 |
2007年 | 43篇 |
2006年 | 29篇 |
2005年 | 32篇 |
2004年 | 33篇 |
2003年 | 21篇 |
2002年 | 27篇 |
2001年 | 43篇 |
2000年 | 49篇 |
1999年 | 40篇 |
1998年 | 51篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 10篇 |
1994年 | 15篇 |
1993年 | 6篇 |
1992年 | 14篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有1013条查询结果,搜索用时 15 毫秒
81.
82.
分析了2000年1月28日随州和信阳交界处发生的ML4.2地震前,信阳地震台(△=35km)定点形变中短期及临震异常特征。分析研究表明:该次地震前信阳台目视水管倾斜仪EW向测值从1999年6开始出现反向变化,NS向测值从1999年3月开始出现加速变化;水平摆倾余仪EW向和NS向测值分别从1999年2月和1999年6月开始出现反向变化。这些异常于2000年下半年结束。震前3天水管倾斜仪EW向测值出现加速变化;震前5-8天NS向测值除了出现加速变化外,还出现突跳。城前约20天,水平摆倾斜仪2个方向测值构出现了准周期性波动变化。另外,形变固体潮潮汐因子也有明显异常。 相似文献
83.
84.
Sven HARTMANN Institute for Hydrosciences German Armed Forces University Munich Neubiberg Germany. 《国际泥沙研究》2001,16(2)
1 BASIC PROBLEMFlood protecton, sPreaing of settlements and occuPatin Of river valleys were maor reasons to damand lindt rivers throughout Europe in the ndd 19th century. Engineers of those days often knew very wellabout the effects of their plannings: shortening the river length would accelerat the now and thusencourage the erosion into the river's sedAnents. Two vital advanages could be obtalned from that kindof constrUction, landuse of the fOrmer flood plains on the one and increasin… 相似文献
85.
Thomas ELSNERand Sven HARTMANN Institute for Hydrosciences German Armed Forces University Munich Neubiberg Germany. Institute for Hydrosciences German Armed Forces University Munich Neubiberg Germany. 《国际泥沙研究》2001,16(2)
1 THE LOWhR unR INNThe Inn river has its source in the alPine region of the GraubUnden canton of Switzerand. ThecatChment area of about 260(X} kIn2 includes mountains of the central Alpes up to 40(X) m. The river runs5l7 km thrOugh the countries of SwitZerand, Austria and Germany on itS way into the Danube mver. Thedischarge of the river at its mouth in the city of Passau is mainly infiuenced by the snow melt in themountainous catchment area and vches between apProx. 200 m3ls durin… 相似文献
86.
利用粤闽交界地区、珠江三角洲地区连续10年左右的地下流体资料,研究利用多层次跟踪法进行地震短期预测的效果,结果表明,该法的粤闽交界及近海地区的应用效果较好,但在珠江三角洲及近海地区暂不宜应用。 相似文献
87.
88.
The spatial characteristic of the short-term and imminent anomalies of waterradonbe┐foreearthquakeinthemainlandofChina 总被引:1,自引:0,他引:1
Thespatialcharacteristicoftheshort┐termandimminentanomaliesofwaterradonbe┐foreearthquakeinthemainlandofChinaXUE-BINDU(杜学彬),X... 相似文献
89.
A long-range transport model with nonlinear chemical reactions is described. The model contains 35 pollutants and 70 chemical reactions. This is a Eulerian model defined on a space domain containing the whole of Europe. The spherical space domain (corresponding to the Earth's surface covered by the model) is mapped into a square plane domain and discretized by using a 32×32 grid. The grid increments are equidistant (both along the Ox axis and along the Oy axis). The choice of values of the physical parameters involved in the model and the numerical treatment of the model are shortly discussed. The model is tested with meteorological data for 1985 and 1989. The numerical results are compared with measurements at stations located in different European countries. Extensive comparisons of ozone concentrations for July 1985 with measurements taken at 24 European stations are also carried out. Results concerning three episodes in July 1985 as well as results obtained in the study of the sensitivity of the ozone concentrations to variations of NO
x
and/or anthropogenic VOC emissions are presented. The advantages and the limitations of such a model are discussed. The model is continuously improved by adding new modules to it. The plans for improvements in the near future are outlined. 相似文献
90.
Since 1979 the repeated observations and experiments of geomagnetic total intensity and vertical component have been carried
out for ten years in the geomagetic network which is located in Jiangsu Province, China. Three earthquakes aboveM
s 5.0 occurred during the decade, and some seismomagnetic effects were observed. The observation results show that the anomalies
of the vertical geomagnetic component can’t be observed untill some months before the earthquake (M
s>5.0) in this area.
In this paper it is suggested that a densely distributed network for continuous observation of geomagnetic vertical component
may catch seismomagnetic anomalies and thus improve earthquake prediction in the light of the geomagnetic measurements of
the mid — or — low latitude locations.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 80–87, 1991.
This study is sponsored by the Chinese Joint Seismological Science Foundation. 相似文献