全文获取类型
收费全文 | 1625篇 |
免费 | 64篇 |
国内免费 | 34篇 |
专业分类
测绘学 | 44篇 |
大气科学 | 85篇 |
地球物理 | 340篇 |
地质学 | 998篇 |
海洋学 | 62篇 |
天文学 | 121篇 |
综合类 | 13篇 |
自然地理 | 60篇 |
出版年
2023年 | 4篇 |
2022年 | 41篇 |
2021年 | 47篇 |
2020年 | 43篇 |
2019年 | 36篇 |
2018年 | 117篇 |
2017年 | 125篇 |
2016年 | 107篇 |
2015年 | 69篇 |
2014年 | 101篇 |
2013年 | 135篇 |
2012年 | 79篇 |
2011年 | 90篇 |
2010年 | 61篇 |
2009年 | 81篇 |
2008年 | 77篇 |
2007年 | 43篇 |
2006年 | 48篇 |
2005年 | 37篇 |
2004年 | 42篇 |
2003年 | 37篇 |
2002年 | 29篇 |
2001年 | 14篇 |
2000年 | 22篇 |
1999年 | 14篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 8篇 |
1995年 | 13篇 |
1994年 | 13篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 15篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 14篇 |
1981年 | 4篇 |
1978年 | 6篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1969年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有1723条查询结果,搜索用时 234 毫秒
91.
Ali Moamen Abdelhady A. Abdelmaksoud Ahmed Darwish M. Essa M. A. 《Natural Resources Research》2020,29(2):1259-1281
Natural Resources Research - The Albian/Cenomanian reservoir is one of the two main reservoirs composing the petroleum system in the Komombo Basin. However, these reservoirs have not previously... 相似文献
92.
Ali Moamen Abdelmaksoud Ahmed Essa M. A. Abdelhady A. Darwish M. 《Natural Resources Research》2020,29(4):2575-2597
Natural Resources Research - Two main reservoirs are producing in Komombo Basin: the first one belongs to the C Member of the Six Hills Formation, and the second belongs to the Albian/Cenomanian... 相似文献
93.
The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted. 相似文献
94.
Houda El Kerni Hasnaa Chennaoui Aoudjehane David Baratoux Mohammed Aoudjehane Andr Charrire Hassan Ibouh Pierre Rochette Yoann Quesnel Minoru Uehara Thomas Kenkmann Gerwin Wulf Michael Poelchau Van Binh Nguyen Maria Aboulahris Samira Makhoukhi Georges Aumaître Didier Bourls Karim Keddadouche 《Meteoritics & planetary science》2019,54(10):2483-2509
Since the discovery of shatter cones (SCs) near the village of Agoudal (Morocco, Central High Atlas Mountains) in 2013, the absence of one or several associated circular structures led to speculation about the age of the impact event, the number, and the size of the impact crater or craters. Additional constraints on the crater size, age, and erosion rates are obtained here from geological, structural, and geophysical mapping and from cosmogenic nuclide data. Our geological maps of the Agoudal impact site at the scales of 1:30,000 (6 km2) and 1:15,000 (2.25 km2) include all known occurrences of SCs in target rocks, breccias, and vertical to overturned strata. Considering that strata surrounding the impact site are subhorizontal, we argue that disturbed strata are related to the impact event. Three types of breccias have been observed. Two of them (br1‐2 and br2) could be produced by erosion–sedimentation–consolidation processes, with no evidence for impact breccias, while breccia (br1) might be impact related. The most probable center of the structure is estimated at 31°59′13.73?N, 5°30′55.14?W using the concentric deviation method applied to the orientation of strata over the disturbed area. Despite the absence of a morphological expression, the ground magnetic and electromagnetic surveys reveal anomalies spatially associated with disturbed strata and SC occurrences. The geophysical data, the structural observations, and the area of occurrence of SCs in target rocks are all consistent with an original size of 1.4–4.2 km in diameter. Cosmogenic nuclide data (36Cl) constrain the local erosion rates between 220 ± 22 m Ma?1 and 430 ± 43 m Ma?1. These erosion rates may remove the topographic expression of such a crater and its ejecta in a time period of about 0.3–1.9 Ma. This age is older than the Agoudal iron meteorite age (105 ± 40 kyr). This new age constraint excludes the possibility of a genetic relationship between the Agoudal iron meteorite fall and the formation of the Agoudal impact site. A chronolgy chart including the Atlas orogeny, the alternation of sedimentation and erosion periods, and the meteoritic impacts is presented based on all obtained and combined data. 相似文献
95.
Natural Resources Research - Recognition of reservoir quality is an important objective in reservoir characterization process. By definition, the quality of a reservoir is described by its... 相似文献
96.
Alameer Zakaria Elaziz Mohamed Abd Ewees Ahmed A. Ye Haiwang Jianhua Zhang 《Natural Resources Research》2019,28(4):1385-1401
Natural Resources Research - An accurate forecasting model for the price volatility of minerals plays a vital role in future investments and decisions for mining projects and related companies. In... 相似文献
97.
Zakia MOKRANE Mustapha BOUDJENAH Yasmina BELKACEM ELHadi MORSLI Ahmed INAL Fahima BOUARAB 《资源与生态学报(英文版)》2019,(4)
浮游植物群的组成是沿海水域状况的极好指标。本研究的目的是探索阿尔及利亚沿海不同地区(东部、中部和西部)浅海沿岸地区浮游植物的空间变异性。浮游植物种群的定性和定量研究是在2012–2013年期间研究船GRINE BELKACEM在该区域采集样本的基础上进行的。定性研究的结果显示硅藻和甲藻具有显著的多样性,在总菌群中分别排名第一和第二(Fr50%)。这一发现也得到了2012年和2013年样本的丰度值的定量证实,这些丰度值大大超过了西部大多数地区的平均值(56%),并且在所有中心地区略高于52%,这代表了硅藻和甲藻两者之间的均衡分布。甲藻对东部地区的数量丰富度(60%)有显著贡献。在东部地区Dia/Dino指数所记录到的最小值也证实了甲藻在该区域的主导地位,特别是在Skikda(0.31)地区更是如此。本文的研究结果还揭示了其他群体(如cocolithophoridae和euglenophyceae)存在的比例较小。 相似文献
98.
Journal of Oceanology and Limnology - The hydrological models and simplified methods of Saint-venant equations are used extensively in hydrological modeling, in particular for the simulation of the... 相似文献
99.
Interest in using Light Detection and Ranging (LiDAR) technology in Transportation Engineering has grown over the past decade. The high accuracy of LiDAR datasets and the efficiency by which they can be collected has led many transportation agencies to consider mobile LiDAR as an alternative to conventional tools when surveying roadway infrastructure. Nonetheless, extracting semantic information from LiDAR datasets can be extremely challenging. Although extracting roadway features from LiDAR has been considered in previous research, the extraction of some features has received more attention than others. In fact, for some roadway design elements, attempts to extract those elements from LiDAR have been extremely scarce. To document the research that has been done in this area, this paper conducts a thorough review of existing studies while also highlighting areas where more research is required. Unlike previous research, this paper includes a thorough review of the previous attempts at data extraction from LiDAR while summarizing the detailed steps of the extraction procedure proposed in each study. Moreover, the paper also identifies common tools and techniques used to extract information from LiDAR for transportation applications. The paper also highlights common limitations in existing algorithms that could be improved in future research. This paper represents a valuable resource for researchers and practitioners interested in knowing the current state of research on the applications of LiDAR in the field of Transportation Engineering while also understanding the opportunities and challenges that lie ahead. 相似文献
100.
利用SRTM绘制东Sahara大型古排水盆地及其对南埃及新发展计划的影响(英文) 总被引:2,自引:0,他引:2
Ahmed Mohamed Youssef 《地球空间信息科学学报》2009,12(3):182-190
In the current study, the shuttle radar topography mission (SRTM) data, with~90 m horizontal resolution, were used to delineate the paleodrainage system and their mega basin extent in the East Sahara area. One mega-drainage basin has been detected, covering an area of 256 000 km2. It is classified into two sub mega basins. The Uweinate sub mega basin, which is composed of four main tributaries, collected water from a vast catchment region and drained eastward from the north, west, and southwest, starting at... 相似文献