全文获取类型
收费全文 | 243篇 |
免费 | 77篇 |
国内免费 | 52篇 |
专业分类
地球物理 | 23篇 |
地质学 | 316篇 |
海洋学 | 2篇 |
综合类 | 25篇 |
自然地理 | 6篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 23篇 |
2020年 | 21篇 |
2019年 | 17篇 |
2018年 | 12篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 17篇 |
2012年 | 19篇 |
2011年 | 25篇 |
2010年 | 17篇 |
2009年 | 17篇 |
2008年 | 12篇 |
2007年 | 15篇 |
2006年 | 22篇 |
2005年 | 8篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有372条查询结果,搜索用时 343 毫秒
151.
152.
153.
154.
《水文科学杂志》2013,58(3):484-496
Abstract During dry weather periods of the year with long rainless intervals, streams slacken to what is generally termed “low flow”. This work presents an analysis of the influence of hydrogeology on low flows, using multiple linear regression, in natural medium and small streams in hilly and mountainous regions of Serbia. The study cases encompass 61 gauged catchments south of the rivers Sava and Danube. Characteristic relevant minimum mean 30-day flows of 80- or 95-percentile exceedence (Q 80%, Q 95%) are taken as dependent variables. Independent variables are the observable hydrogeological quantities: catchment area upstream of a gauging station; surface area of a hydrogeological soil category in a catchment; number of perennial springs of minimum flow higher than or equal to 1 L/s in a gauged catchment; number of perennial springs, each of minimum flow higher than or equal to 1 L/s, in a given hydrogeological soil category of the catchment; cumulative perennial spring flow of minimum single flow higher than or equal to 1 L/s in a catchment; and cumulative perennial spring flow of minimum single flow higher than or equal to 1 L/s in a hydrogeological soil category of a catchment. Through multiple linear regression between the characteristic relevant low flow and the hydrogeological elements, 16 models are developed and analysed, each based on a different combination of hydrogeological elements and characteristic low flow. The regional relationships developed for the minimum mean 30-day flows of 80- and 95-percentile exceedences are evaluated. The statistical tests of the representation quality of each multiple regression relationship show that the models justify the use of hydrogeological elements. 相似文献
155.
Cristian Guevara Ochoa Agustín Medina Sierra Luis Vives Erik Zimmermann Ryan Bailey 《水文研究》2020,34(6):1371-1392
The study of the dynamics of anthropic disturbances that have an effect on the hydrological systems in plains requires integral simulation tools for their diagnosis. The objective of this article is, first, to analyse and reproduce the spatio-temporal interactions between groundwater (GW) and surface water, net recharge, GW level, surface run-off, and evapotranspiration in the upper creek basin of Del Azul, which is located in the centre of the province of Buenos Aires, Argentina, and second, to obtain insights to apply the methodology to other similar situations. For this purpose, a model coupling the semidistributed hydrological model (Soil and Water Assessment Tool [SWAT]) and the hydrogeological model (MODFLOW) has been used. A simulation was carried out for a period of 13 years (2003–2015) on a daily scale. The application of the SWAT–MODFLOW coupling gave good results based on the adjustment between the calculated flows and levels, reaching a Nash–Sutcliffe of 0.6 and R20.6 at the Seminario hydrometric station located at the watershed outlet point. According to the annual average balance, out of the total rainfall, evapotranspiration accounts for 85%, recharge accounts for 10.2%, and surface run-off accounts for 4.8%. Annual and monthly trends of the stream–aquifer interaction were determined, obtaining on average an annual GW discharge of 34 mm and an annual average recharge of the stream to the aquifer of 1.4 mm. Monthly GW discharges are higher in winter–spring (July to December with an average of 3.3 mm) and lower in summer–autumn (January to June with an average of 2.8 mm). The monthly average recharge of the stream towards the aquifer varies from 0.02 to 0.36 mm and is higher in March, May, and August, when water excess is produced in the basin. Through the analysis of coupled modelling, it is possible to analyse and reproduce the spatio-temporal transitions of flow existing between the stream, the hyporheic zone, and the aquifer. 相似文献
156.
157.
158.
煤层气开发中的层间矛盾问题——以柳林地区为例 总被引:2,自引:0,他引:2
直井分层压裂及合层排采能有效降低煤层气勘探开发成本,提高煤层气产能,但层间矛盾的干扰制约了这一排采工艺的推广。借鉴常规油气层间矛盾问题相关理论,首次提出并总结了煤层气开发中层间矛盾的概念、特点和影响因素。通过分析柳林地区典型井产能曲线特征,剖析了该区层间矛盾的特征和原因。结果表明:柳林地区合层排采太原组煤层(8号+9号)和合层排采山西组与太原组煤层(3号+4号+5号与8号+9号)时,层间矛盾问题严重;引起该层间矛盾的原因有煤层物性特征和煤层顶底板水文地质条件因素,其中8号煤层顶板水文地质条件是引发该区层间矛盾的主要因素。 相似文献
159.
160.
岩溶水系统的水化学曲线及其在水文地质研究中的应用 总被引:5,自引:0,他引:5
为了认识水文地质条件与岩溶泉水化学之间的关系,以西南地区的6个典型岩溶水系统丫吉试验场S31号泉、毛村地下河、官村地下河、陈旗岩溶泉、青木关地下河以及金佛山水房泉为例进行研究。通过对比发现,在这些强烈非均质的山区裸露型岩溶水系统中,仪器能够实现自动化监测的电导率、温度和pH值等指标的水化学曲线存在差异。分析可知控制水化学变化的主要因素如下:首先是降雨补给引起系统的水量与碳酸盐岩溶解过程的变化;其次是CO2气体随降雨进入含水层,促进碳酸盐岩的溶解;最后是地表污染物的淋滤。当电导率、水温、pH曲线出现降低和碳酸盐岩矿物饱和指数下降时,反映的是岩溶水的稀释作用;当电导率曲线出现高峰时,反映的是岩溶水补给的CO2效应,此时水中二氧化碳分压(pCO2)升高;当场雨中水化学曲线的变化滞后于水文动态曲线时,反映的是岩溶管道的活塞流效应;与人类活动有关的NO3-等污染物质量浓度在降雨后出现高峰,反映土壤的降雨淋滤作用,并可能影响电导率的变化趋势。某个系统的水化学曲线趋向于经常出现某几种效应,并且彼此的类型不同,表明了降雨补给的面状渗流方式和集中灌入方式对岩溶水影响的强弱不同,以及系统在径流方式和调蓄机制上的差异。一般而言:以面状补给方式为主的系统,水化学曲线多表现为CO2效应,较少出现稀释作用;而岩溶发育强烈的系统,降雨补给受控于溶蚀裂隙和管道,其水化学曲线较多出现稀释作用,较少出现CO2效应;以管道为主要径流方式的系统易出现活塞流效应,而包气带厚度大和含水层储水能力强的系统水化学变化被减弱。 相似文献