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11.
城市用地与人口的异速增长和相关经验研究   总被引:16,自引:5,他引:16  
梁进社  王旻 《地理科学》2002,22(6):649-654
由于城市土地利用变化涉及的因素多,使获取动态研究研究所需的资料十分困难,所以,用少数几个主要因素定量地表达其变化就显得十分重要。从前人的成果,即以人口表示的城市位序-规模法则和建成区面积表示的位序-规模法则出发,绽绎出城市的用地规模和人口数量呈异速增长。这意味着,如果把整个城市看成是一个生命有机体,那么作为反映城市特征的城市用地规模和城市人口这两个重要变量,就是城市这个有机体的两个器官,他们的增长率是成比例的。还通过这个关系建立了城市建成区面积与市场人口和经济发展水平的数学模式。对我国部分城市的经验研究在一定程度上分别证明了这两经验关系。  相似文献   
12.
地下物探在有色金属矿山寻找隐伏矿体的应用   总被引:4,自引:0,他引:4  
介绍了地下地球物理找矿方法在几个典型有色金属矿山进行生产找矿的实例,根据对不同深度的面积工作获得的系列直流电法、电磁法异常的计算分析,分别提出解释推断及施工建议,经工程验证,取得了显著的地质效果。  相似文献   
13.
Several stratospheric chemistry modules from box, 2-D or 3-D models, have been intercompared. The intercomparison was focused on the ozone loss and associated reactive species under the conditions found in the cold, wintertime Arctic and Antarctic vortices. Comparisons of both gas phase and heterogeneous chemistry modules show excellent agreement between the models under constrained conditions for photolysis and the microphysics of polar stratospheric clouds. While the mean integral ozone loss ranges from 4–80% for different 30–50 days long air parcel trajectories, the mean scatter of model results around these values is only about ±1.5%. In a case study, where the models employed their standard photolysis and microphysical schemes, the variation around the mean percentage ozone loss increases to about ±7%. This increased scatter of model results is mainly due to the different treatment of the PSC microphysics and heterogeneous chemistry in the models, whereby the most unrealistic assumptions about PSC processes consequently lead to the least representative ozone chemistry. Furthermore, for this case study the model results for the ozone mixing ratios at different altitudes were compared with a measured ozone profile to investigate the extent to which models reproduce the stratospheric ozone losses. It was found that mainly in the height range of strong ozone depletion all models underestimate the ozone loss by about a factor of two. This finding corroborates earlier studies and implies a general deficiency in our understanding of the stratospheric ozone loss chemistry rather than a specific problem related to a particular model simulation.  相似文献   
14.
正态化克立格法是对传统储量计算方法的改革和创新。其计算过程的科学性和计算结果的正确性在路腊汞矿作了探采对比试算,取得了良好的结果。  相似文献   
15.
We present new Thellier-Thellier palaeointensity results from three cooling units (32 samples) of Inner Mongolia lava flows (91.7 Ma) emplaced during the Cretaceous Normal Superchron (CNS). Based on rock-magnetic and microscopy observations the magneto-mineralogy of all samples is determined to be primary and unaltered high-Ti titanomagnetite. Accepted palaeointensity determinations, obtained in the 80-200 °C temperature interval, are of good technical quality with positive standard partial thermoremanent magnetisation (pTRM) checks and pTRM-tail checks. Obtained palaeointensity estimates range from 14.7 to 28.0 μT, with virtual axial dipole moments (VADM) of 2.4 to 4.6 (× 1022 Am2). The data agree well with recently published results from the same region and, combining the two datasets, we obtain independent estimates from six different cooling units yielding a time-averaged VADM of 3.2 ± 1.6 (× 1022 Am2). These data suggest a relatively low dipole moment towards the end of the Cretaceous Normal Superchron.  相似文献   
16.
ATEM-Ⅱ型瞬变电磁系统的实际应用   总被引:1,自引:0,他引:1  
介绍了ATEM-II型瞬变电磁系统在矿产普查、大型矿山潜力资源探查、地下水勘察、城市工程勘察和地下活断层调查、矿井透水预测等领域的应用实例.  相似文献   
17.
The Taranto Gulf of southern Italy provides an excellent case where it is possible to document the importance of normal faults in displacing terraced deposits. The study area is located at the front of the southern Apennines, that is a fold-and-thrust belt developed following the closure of the Mesozoic Tethys Ocean, and the deformation of the Adriatic passive margin during Tertiary and Quaternary times. The outer, eastern parts of the belt were structured in Quaternary, i.e. up to Middle Pleistocene times.The front of the chain is partially sealed by Pliocene–Pleistocene foredeep deposits, which represent the infill of the Bradanic Trough. The upper portion of the middle Pleistocene succession consists of marine sands and conglomerates that in the previous literature have been arranged in several orders of terraces. Analysis of aerial photographs and geomorphological mapping has shown the occurrence of prominent geomorphic lineaments, which appear to control the local drainage pattern. Some of these structures coincide with the map trace of normal faults that produce vertical offsets of the marine terrace surfaces in the order of ca. 10 m each. Many of the fault escarpments reduce their elevation and terminate laterally. In other cases fault escarpments are laterally continuous and can be traced for up to 3–4 km. Scarp height is between 2 and 10 m. Their mean trend ranges from NNE–SSW to ENE–WSW and defines an arcuate pattern that mimics the present coastline.An accurate geomorphological, sedimentological and stratigraphic analysis has been carried out in a selected area of the Bradanic Trough (Pisticci transect) to investigate in detail the relationships between normal faults and the development of the terraces. This analysis allowed us to recognise five facies associations related to the upper and lower beachface and to the neritic clays which represent the substratum of the terraces. More importantly, we observed that all the terraced deposits in the Pisticci transect could be referred to a single sedimentary body displaced by faults. The terraced deposits are related to an event of beach progradation, of Middle Pleistocene age, which has been documented in other areas of the Italian peninsula. These results outline an intimate relationship between the arcuate trend of the recognised fault set and the present coastline pattern. The development of the normal faults can be related to large-scale gravitational processes developed after the general tilting towards the SE of the Bradanic Trough.  相似文献   
18.
In this paper, we apply current geological knowledge on faulting processes to digital processing of Digital Elevation Models (DEM) in order to pinpoint locations of active faults. The analysis is based on semiautomatic interpretation of 20- and 60-m DEM and their products (slope, shaded relief). In Northern–Eastern Attica, five normal fault segments were recognized on the 20-m DEM. All faults strike WNW–ESE. The faults are from west to east: Thriassion (THFS), Fili (FIFS), Afidnai (AFFS), Avlon (AVFS), and Pendeli (PEFS) and range in length from 10 to 20 km. All of them show geomorphic evidence for recent activity such as prominent range-front escarpments, V-shaped valleys, triangular facets, and tilted footwall areas. However, escarpment morphometry and footwall geometry reveal systematic differences between the “external” segments (PEFS, THFS, and AVFS) and the “internal” segments (AFFS and FIFS), which may be due to mechanical interaction among segments and/or preexisting topography. In addition, transects across all five escarpments show mean scarp slope angles of 22.1°±0.7° for both carbonate and metamorphic bedrock. The slope angle equation for the external segments shows asymptotic behaviour with increasing height. We make an empirical suggestion that slope angle is a function of the long-term fault slip rate which ranges between 0.13 and 0.3 mm/yr. The identified faults may rupture up to magnitude 6.4–6.6 earthquakes. The analysis of the 60-m DEM shows a difference in fault patterns between Western and Northern Attica, which is related to crustal rheology variations.  相似文献   
19.
Tectono-stratigraphic analysis of the East Tanka fault zone (ETFZ), Suez Rift, indicates that the evolution of normal fault segments was an important control on syn-rift depositional patterns and sequence stratigraphy. Sedimentological and stratigraphic analysis of the Nukhul Formation indicates that it was deposited in a narrow (ca 1–2 km), elongate (ca 5 km), fault-bounded, tidally influenced embayment during the low subsidence rift-initiation phase. The Nukhul Formation is composed of transgressive (TST) and highstand (HST) systems tract couplets interpreted as reflecting fault-driven subsidence and the continuous creation of accommodation in the hangingwall to the ETFZ. The overlying Lower Rudeis Formation was deposited during the high subsidence rift-climax phase, and is composed of forced regressive systems tract (FRST) shallow marine sandbodies, and TST to HST offshore mudstones. Activity on the ETFZ led to marked spatial variability in stratal stacking patterns, systems tracts and key stratal surfaces, as footwall uplift, coupled with regressive marine erosion during deposition of FRST sandbodies, led to the removal of intervening TST–HST mudstone-dominated units, and the amalgamation of FRST sandbodies and the stratal surfaces bounding these units in the footwall. This study indicates that the evolution of normal fault segments over relatively short (i.e. <1 km) length-scales has the potential to enhance or suppress a eustatic sea-level signal, leading to marked spatial variations in stratal stacking patterns, systems tracts and key stratal surfaces. Crucially, these variations in sequence stratigraphic evolution may occur within time-equivalent stratal units, thus caution must be exercised when attempting to correlate syn-rift depositional units based solely on stratal stacking patterns. Furthermore, local, tectonically controlled variations in relative sea level can give rise to syn-rift stacking patterns which are counterintuitive in the context of the structural setting and perceived regional subsidence rates.  相似文献   
20.
随着西部大开发战略的深入实施,如何全面认识旅游业对西部经济落后地区经济的影响,成为旅游学界关注的热点问题之一。通过对石林县社会经济统计数据的综合分析以及实地调研,证实了旅游业对促进石林县国民经济总量扩大、推动产业结构高级化和带动相关产业发展等方面具有积极作用。同时,针对当前石林旅游内部结构和发展质量中存在的旅游产品单一、景区发展失衡和社区受益不足等主要问题,提出了以推动区域经济总体发展和带动农村居民脱贫作为旅游发展的两大基本任务和实现旅游产业增长模式从数量型向内涵型增长转变的基本思路,以及相应的对策。  相似文献   
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