首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   591篇
  免费   68篇
  国内免费   76篇
测绘学   47篇
大气科学   56篇
地球物理   170篇
地质学   241篇
海洋学   62篇
天文学   5篇
综合类   42篇
自然地理   112篇
  2024年   2篇
  2023年   5篇
  2022年   16篇
  2021年   26篇
  2020年   23篇
  2019年   28篇
  2018年   21篇
  2017年   19篇
  2016年   16篇
  2015年   28篇
  2014年   35篇
  2013年   40篇
  2012年   40篇
  2011年   58篇
  2010年   39篇
  2009年   36篇
  2008年   38篇
  2007年   36篇
  2006年   31篇
  2005年   24篇
  2004年   21篇
  2003年   17篇
  2002年   25篇
  2001年   23篇
  2000年   17篇
  1999年   20篇
  1998年   9篇
  1997年   6篇
  1996年   4篇
  1995年   6篇
  1994年   5篇
  1993年   5篇
  1992年   5篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
  1977年   1篇
排序方式: 共有735条查询结果,搜索用时 15 毫秒
1.
利用用友软件对如何合并会计报表进行了初步研究,并以案例的形式阐明了采用用友软件实现合并会计报表的步骤,提出了合并会计报表的编制方法。  相似文献   
2.
为实施中华人民共和国国家标准《南海区拖网网囊最小网目尺寸》,对广东省范围内拖网网囊现状进行摸底调查,结果表明,广东省沿海拖网渔船现用网囊网目尺寸(内径)在16.7~35.2 mm范围内,总体平均为27 mm,均未能达到1989年国家技术监督局发布的中华人民共和国国家标准--《南海区拖网网囊最小网目尺寸》--内径39 mm.  相似文献   
3.
介绍了 2 0 0 1- 2 0 0 2年上海天文台卫星激光测距观测概况和亚厘米级精度的测距实验  相似文献   
4.
Quick-look assessments to identify optimal CO2 EOR storage sites   总被引:1,自引:0,他引:1  
A newly developed, multistage quick-look methodology allows for the efficient screening of an unmanageably large number of reservoirs to generate a workable set of sites that closely match the requirements for optimal CO2 enhanced oil recovery (EOR) storage. The objective of the study is to quickly identify miscible CO2 EOR candidates in areas that contain thousands of reservoirs and to estimate additional oil recovery and sequestration capacities of selected top options through dimensionless modeling and reservoir characterization. Quick-look assessments indicate that the CO2 EOR resource potential along the US Gulf Coast is 4.7 billion barrels, and CO2 sequestration capacity is 2.6 billion metric tons. In the first stage, oil reservoirs are screened and ranked in terms of technical and practical feasibility for miscible CO2 EOR. The second stage provides quick estimates of CO2 EOR potential and sequestration capacities. In the third stage, a dimensionless group model is applied to a selected set of sites to improve the estimates of oil recovery and storage potential using appropriate inputs for rock and fluid properties, disregarding reservoir architecture and sweep design. The fourth stage validates and refines the results by simulating flow in a model that describes the internal architecture and fluid distribution in the reservoir. The stated approach both saves time and allows more resources to be applied to the best candidate sites.  相似文献   
5.
就贵州省当前矿产资源储量勘查地质报告中出现的问题进行了梳理,指出了问题的所在,提出应引起注意和重视的问题及改进建议。  相似文献   
6.
7.
LI  Wen-long 《中国海洋工程》2003,17(4):541-550
The floating oil storage system has been proposed as a new facility for Strategic Petroleum Reserve (SPR) in China. Mooring is one of the key technologies to ensure the safety, reliability, and performance of the oil storage system. This paper describes the concept, analysis, design and reliability of the mooring system. For mooring system design of these oil vessels, analysis is essential of the behavior of the vessel in connection with mooring facilities of nonlinear resilience. A nonlinear mathematical model for analyzing a moored vessel is established and solved. Some results of numerical simulations are presented. Assessment of the safety regarding the mooring system in terms of failure probability is carried out. Another simulation model for calculating the failure probability of the mooring system is proposed. The design parameters that have an influence on the characteristics of the failure probability have been identified. The simulation results show that the mooring system has an annual reliab  相似文献   
8.
In recent years, a series of large low and medium abundance oil and gas fields are discovered through exploration activities onshore China, which are commonly characterized by low porosity-permeability reservoirs, low oil/gas column height, multiple thin hydrocarbon layers, and distribution in overlapping and connection, and so on. The advantageous conditions for large-area accumulation of low-medium abundance hydrocarbon reservoirs include: (1) large (fan) delta sandbodies are developed in the hinterland of large flow-uncontrolled lake basins and they are alternated with source rocks extensively in a structure like "sandwiches"; (2) effective hydrocarbon source kitchens are extensively distributed, offering maximum contact chances with various sandbodies and hydrocarbon source rocks; (3) oil and gas columns are low in height, hydrocarbon layers are mainly of normal-low pressure, and requirements for seal rock are low; (4) reservoirs have strong inheterogeneity and gas reservoirs are badly connected; (5) the hydrocarbon desorption and expulsion under uplifting and unloading environments cause widely distributed hydrocarbon source rocks of coal measures to form large-area reservoirs; (6) deep basin areas and synclinal areas possess reservoir-forming dynamics. The areas with great exploration potential include the Paleozoic and Mesozoic in the Ordos Basin, the Xujiahe Formation in Dachuanzhong in the Sichuan basin, deep basin areas in the Songliao basin etc. The core techniques of improving exploration efficiency consist of the sweetspot prediction technique that focuses on fine characterization of reservoirs, the hydrocarbon layer protecting and high-speed drilling technique, and the rework technique for enhancing productivity.  相似文献   
9.
基于LongruanGIS3.0开发的电子地质报告系统包括数据库管理系统、图形处理系统和文字表格处理系统三部分。在介绍该系统的总体设计、功能实现和系统特点的基础上,总结了该软件的几方面优势:具有数据共享、数据集成、自动成图、功能开放的技术优势;具有开放的数据交换格式以及将CAD与GIS软件结合起来的强大图形编辑、查询、空间分析功能。  相似文献   
10.
本文简述了开发地震快报系统的主要技术。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号