全文获取类型
收费全文 | 152篇 |
免费 | 72篇 |
国内免费 | 120篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 19篇 |
地球物理 | 111篇 |
地质学 | 181篇 |
海洋学 | 10篇 |
综合类 | 19篇 |
自然地理 | 1篇 |
出版年
2020年 | 1篇 |
2011年 | 22篇 |
2010年 | 12篇 |
2009年 | 25篇 |
2008年 | 5篇 |
2007年 | 12篇 |
2006年 | 41篇 |
2005年 | 40篇 |
2004年 | 81篇 |
2003年 | 30篇 |
2002年 | 10篇 |
2001年 | 15篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1984年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有344条查询结果,搜索用时 15 毫秒
281.
凉水煤矿采用二维地震寻找第三系煤田 总被引:1,自引:0,他引:1
金秀芹 《吉林大学学报(地球科学版)》2010,(Z1)
凉水煤矿为第三系煤田,其特点是:主采煤层为褐煤,与围岩波阻抗差小;深层地层的层速度低,波阻抗差也比较小,深层反射条件差。针对此特点,在采集、处理环节采取了诸如混凝土砂浆封井、初至折射静校正、人工提取干扰等提高信噪比的措施,取得了比较好的勘查成果。 相似文献
282.
283.
This is an investigation of exchanges of energy and water between the atmosphere and thevegetated continents,and the impact of and mechanisms for land surface-atmosphere interactionson hydrological cycle and general circulation by implementing the Simplified Simple Biosphere(SSiB)model in a modified version of IAP/LASG global spectral general model(L9R15 AGCM).This study reveals that the SSiB model produces a better partitioning of the land surface heat andmoisture fluxes and its diurnal variations,and also gives the transport of energy and water amongatmosphere,vegetation and soil explicitly and realistically.Thus the coupled SSiB-AGCM runslead to the more conspicuous improvement in the simulated circulation,precipitation,mean watervapor content and its transport.particularly in the Asian monsoon region in the real world thanCTL-AGCM runs.It is also pointed out that both the implementation of land surfaceparameterizations and the variations in land surface into the GOALS model have greatly improvedhydrological balance over continents and have a significant impact on the simulated climate.particularly over the massive continents.Improved precipitation recycling model was employed to verify the mechanisms for landsurface hydrology parameterizations on hydrological cycle and precipitation climatology in AGCM.It can be argued that the recycling precipitation rate is significantly reduced,particularly in the aridand semi-arid region of the boreal summer hemisphere,coincident with remarkable reduction inevapotranspiration over the continental area.Therefore the coupled SSiB-AGCM runs reduce thebias of too much precipitation over land surface in most AGCMs,thereby bringing the simulatedprecipitation closer to observations in many continental regions of the world than CTL-AGCMruns. 相似文献
284.
该文探讨了涂浦地区的农业地质地球化学背景优势特征,确认2处桃、枣和5处用材林基地地质背景优势区,为有关部门合理规划农业生产提供了依据。 相似文献
285.
利用重力、航磁、航电、航空γ能谱、地震测深等多种地球物理资料,对新疆北部的康古尔塔格断裂带深部地质特征进行了探讨.认为该断裂带两侧的地壳结构有较大差异,北侧地壳为二层结构,上地壳中发育有高密度、强磁性、高速度的镁铁质岩;南侧地壳为三层结构,同时有低速度层发育.康古尔塔格断裂带是划分准噶尔与塔里木两大板块的一条重要界线. 相似文献
286.
详细地介绍了一个综合运用遥感、地质、物探、化探等地学信息进行区域性矿产资源勘查与预测的数学模型.模型中在对各类地学信息进行有益的变换、提取的基础上,借助概率论中广义二项分布函数对其进行综合处理与分析.该模型的输出结果不仅为区域性矿产预测提供定量分析数据,而且还是一种寻找与已知矿床具有类似地质条件和地球物理及地球化学环境的有效方法. 相似文献
287.
Chen Jianguo Dietrich R. A. Zhu Jimao Associate Professor Dept. of Naval Architecture Ocean Engineering Shanghai Jiaotong University Shanghai Dipl. Ing. Dept. of Structural Fluid Mechanics GKSS Research Center Geesthacht Germany Professor Dept. of Naval Architecture Ocean Engineering Shanghai Jiaotong University Shanghai 《中国海洋工程》1994,(3)
-By using gas-liquid two-phase flow theory, a modified mathematical model based on the computational fluid dynamics method SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) is introduced to investigate implosion phenomena in high pressure chambers systematically. A theoretical simulation-prediction method, which is independent of experimental data, is developed in the paper and great improvement has been made on the topic. In the paper, various implosion situations have been simulated and predicted. Effects of a series of factors influencing implosion results and methods of reducing implosion danger have been analysed. The analysis results are of importance to underwater engineering practice. 相似文献
288.
Integration of Real-Time Chemical Sensors for Deep Sea Research 总被引:7,自引:0,他引:7
There is a great demand for in-situ real-time chemical sensors in the oceanographic research, to measure the chemical components under the deep sea. The ISE (Ion Selective Electrode) is commonly used as a detecting part of deep-sea electro-chemical sensors. The paper highlights the solidification and micromation of the working and reference electrodes. The sensors of pH and H2S with a thermal probe are accomphshed after the solution of configuration of electrodes and signal processing. The sensor system has been tested successfully in the cruise of DY105-12, 14 sponsored by China Ocean Mineral Research and Exploitation Association(COMRA). 相似文献
289.
A seismic survey by 10 shallow profiles and 6 ultra-shallow profiles was performed in Changbaishan Tianchi volcanic region in 2002. The result shows that there are three (in some areas as many as seven) stable interfaces in the survey region, but no reflection phases are found in depths greater than 500 m. The number of interfaces in the southwestern part is obviously greater than in the northwestern part of Tianchi volcano, which suggests that the faults in the southwest have a stronger controlling power over the flow direction of volcano-spewed lava as compared with those in the northwest. Six shallow faults exist in the survey region. The shallow faults are nearly vertical graben-like faults and are mostly distributed on the southwest of Tianchi crater, indicating that volcanic activities in the southwest are stronger than in the northwest. On this ground, it could be further deduced that the NE-trending major fault of Tianchi volcano ( the Liudaogou-Tianchi-Zengfengshan fault) is more active than the NW-trending Baishanzhen-Tianchi-Jince fault. 相似文献
290.