全文获取类型
收费全文 | 608篇 |
免费 | 98篇 |
国内免费 | 52篇 |
专业分类
测绘学 | 8篇 |
大气科学 | 23篇 |
地球物理 | 282篇 |
地质学 | 286篇 |
海洋学 | 108篇 |
综合类 | 34篇 |
自然地理 | 17篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 9篇 |
2021年 | 17篇 |
2020年 | 21篇 |
2019年 | 24篇 |
2018年 | 20篇 |
2017年 | 24篇 |
2016年 | 35篇 |
2015年 | 29篇 |
2014年 | 49篇 |
2013年 | 43篇 |
2012年 | 16篇 |
2011年 | 40篇 |
2010年 | 28篇 |
2009年 | 47篇 |
2008年 | 53篇 |
2007年 | 35篇 |
2006年 | 40篇 |
2005年 | 32篇 |
2004年 | 31篇 |
2003年 | 17篇 |
2002年 | 16篇 |
2001年 | 16篇 |
2000年 | 9篇 |
1999年 | 21篇 |
1998年 | 13篇 |
1997年 | 13篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有758条查询结果,搜索用时 421 毫秒
51.
Cheng Kuei-Hsiang 《中国地震研究》2001,15(3):311-320
INTRODUCTIONSeveMmethdsdPOtential analyslsfor medium-and short-termpredlctlon dl’l;lln shocks weredevelopedbaseduponthe pnnclpledInaccufatemeasurementoffOCfOCustheoryaMthepattemdmainshocks.These analytic methods can be used to predict strong earthop拙es In shallow layers on thesubducting plate boundeq In squeezed zones.More than a half of strong earthquakes In the world。located inthe shallow depth tthe suMuctingplate boundw In s仰eezed zones.This paPerfirst Statesthe philoso… 相似文献
52.
浅地层剖面仪在水域工程勘察中的应用 总被引:7,自引:0,他引:7
扼要介绍了水上浅地层剖面仪的方法技术,列举了该法在浅海,内河和湖泊减种典型环境及相应的地质条件下勘测所得到的剖面记录及地质解释结果,指出了运用该方法所能解决的工程地质问题。 相似文献
53.
Nenad Gucunski 《Soil Dynamics and Earthquake Engineering》1996,15(8):485-497
The analysis of the response of a flexible circular foundation on layered media due to an arbitrarily distributed vertical loading is presented. The analysis is based on the ‘ring method’ approach, i.e. discretization of the foundation in a set of concentric rings. The arbitrarily distributed loading is expanded in the circumferential direction in a Fourier series. The influence coefficient matrix of soil for each element of the series is evaluated utilizing the stiffness matrix approach. The stiffness matrix of the foundation is obtained from the finite difference energy method approach. Numerical examples illustrate the influence of several soil-foundation parameters on the rocking response of a foundation. Results are presented in terms of displacement and soil reaction distributions and impedance functions point to significantly different responses of flexible and rigid foundations. 相似文献
54.
Sabine Hilt Elisabeth M. Gross Michael Hupfer Harald Morscheid Jens Mhlmann Arnulf Melzer Jens Poltz Stefan Sandrock Eva-Maria Scharf Susanne Schneider Klaus van de Weyer 《Limnologica》2006,36(3):155-171
One of the most serious problems caused by eutrophication of shallow lakes is the disappearance of submerged macrophytes and the switch to a turbid, phytoplankton-dominated state. The reduction of external nutrient loads often does not result in a change back to the macrophyte-dominated state because stabilising mechanisms that cause resilience may delay a response. Additional internal lake restoration measures may therefore be needed to decrease the concentration of total phosphorus and increase water clarity. The re-establishment of submerged macrophytes required for a long-term stability of clear water conditions, however, may still fail, or mass developments of tall-growing species may cause nuisance for recreational use. Both cases are often not taken into account when restoration measures are planned in Germany, and existing schemes to reduce eutrophication consider the topic inadequately. Here we develop a step-by-step guideline to assess the chances of submerged macrophyte re-establishment in shallow lakes. We reviewed and rated the existing literature and case studies with special regard on (1) the impact of different internal lake restoration methods on the development of submerged macrophytes, (2) methods for the assessment of natural re-establishment, (3) requirements and methods for artificial support of submerged macrophyte development and (4) management options of macrophyte species diversity and abundance in Germany. This guideline is intended to help lake managers aiming to restore shallow lakes in Germany to critically asses and predict the potential development of submerged vegetation, taking into account the complex factors and interrelations that determine their occurrence, abundance and diversity. 相似文献
55.
Wang Sheng-zu 《中国地震研究》2006,20(3):326-338
INTRODUCTIONAccording to the“netlike plastic-flow (NPF)”continental dynamics model ( Wang, 1993a ,1993b; Wang,et al .,2001c) ,the continental lithosphere generally includes 4 tectonic deformationlayers frombottomtotop:the NPFlayer (i .e .thelowerlithosphere ,includingthelithospheric mantleandlower crust) ,the transitional weak layer distributed discontinuously (i .e .the so-called low-velocity/high-conductivitylayer) ,the shear fracturinglayer (i .e .the seismogenic layer inthe upperc… 相似文献
56.
矿产勘查工作综合性很强,所需要应用的知识非常广泛,不仅涉及到基础地质、成矿理论、勘查技术手段等地质学科知识,还要综合运用数学、化学、计算机等新方法、新技术。从板块构造、成矿背景以及成矿系列、成矿系统等方面介绍了其地质基础,并阐述了所用到的新方法、新理论的发展现状。 相似文献
57.
里下河地区浅部沉积物多为全新世中、晚期堆积,多数地区缺失全新世早期沉积。沉积物以淤泥质亚粘土、亚粘土、亚砂土,粉砂质淤泥、淤泥质粉砂、淤泥及泥炭为特征。沉积前的古地貌为四周高、中间低的碟形盆地。古气候经历了温湿—暖湿—温湿—温干的变化过程。区内曾有两次海侵,第一次海侵发生在全新世早中期,范围几乎遍及全区;第二次海侵发生在全新世晚期,规模小、范围窄、时间短,为海水沿江河倒灌、回溯形起。该区古环境自全新世以来经历了浅水海湾—古泻湖—湖沼地及平原的演变过程,最终形成现今河湖稠密的低凹平原。 相似文献
58.
Phil Dyke 《Ocean Dynamics》2007,57(4-5):239-244
This is a history of shallow sea modelling developments as viewed through the Jonsmod modelling conferences over the past
25 years. The conferences are reviewed, and what emerges is a coherent progression to present-day modelling. We also see advances
in computing and oceanographic observation, although these are, of course, incidental to the modelling from the point of view
of these conferences. 相似文献
59.
震后野外考察及航空摄影发现的地裂缝带,说明唐山断裂与1976年唐山7.8级大地震的发震构造有密切关系。用卫星遥感信息和浅层地震勘探结果对唐山断裂的活动性做了新的研究。卫星图像解释结果表明:震前一年多时间内,NE向的唐山断裂被NNW向断裂截切而NWW向断裂受到牵引,因而显示出右旋走滑的活动形迹。浅层地震勘探结果则证明,唐山断裂是倾向NW,高倾角的右旋走滑正断层,它断错了全新统(Q4)、晚更新统(Q3)、中更新统(Q2)和早更新统(Q1)地层 相似文献
60.
SummarySome Foundation Stability Problems of the Railway Bridge over the Mala Rijeka The authors presented an outlay of problems occurring in estimating the stability of rocky slopes loaded by large vertical forces. General attitudes, kept by the authors during the stability analysis for an actual case — foundation of piers No. 3 and 4 of the railway bridge across the Mala Rijeka, are also presented. The results of calculation as well as the advantages of the approach applied are outlined in the paper. Finally, general conclusions are drawn regarding the method to be kept in solving the stability of slopes loaded by large artificial loading.With 7 Figures 相似文献