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81.
断裂韧度试样CCNBD宽范围应力强度因子标定 总被引:6,自引:3,他引:3
国际岩石力学学会(ISRM)在1995年提出了一种新型岩石断裂韧度试样--人字形切槽巴西圆盘试样CCNBD,但是,其断裂韧度计算公式中的重要参数(即无量纲应力强度因子的标定)仍存在问题。采用一种新的分片合成方法并结合有限元法,参照ISRM给出的CCNBD试样的尺寸限制,对该范围试样的应力强度因子进行了宽范围的标定,以便在试验中能因地制宜地选用不同几何参数的CCNBD试样。结果表明:分片合成方法的计算值有很高的精度,不但减少了工作量,也使标定的无量纲应力强度因子比现有文献值更加准确、可靠。 相似文献
82.
《International Geology Review》2012,54(5):593-614
Basically, two main types of statistical methods – robust and outlier-based – are available for handling experimental data; we document here the application of the outlier-based method. Due to the unavailability of a suitable software system for statistically correct application of the outlier-based method, a new computer program, DODESSYS (Discordant Outlier DEtection and Separation SYStem), was written for the application of 33 discordancy test variants to experimental data, constituting contaminated or uncontaminated normal statistical samples. We illustrate the application of the discordant outlier-based scheme by five specific examples; three include univariate data for which this procedure was specifically designed and two are for bivariate data for which this methodology can be easily adopted. We thus report new statistical information on two reference materials (granite G-2 and sediment IAEA-417), bryozoan species from eastern Oman, a new improved Na/K geothermometric equation, and a more significant correlation with water depth of the abundance of meiofauna from the Gulf of Mexico. Recently, two sets of multi-dimensional discrimination diagrams for basic as well as acid rocks have been proposed from statistically correct methodology of natural logarithm-transformation of element ratios; the diagrams also require that these ratios should be normally distributed. We present numerous examples of application of these new diagrams for inferring tectonic setting of Archaean to Recent rocks, both before and after testing the datasets for discordant outliers. We recommend that outlying observations should always be evaluated for their discordancy. 相似文献
83.
Due to the advances in Web technologies,various raster maps are available through Web Map Services such as Google maps and Yahoo maps.These online maps are used to visualize diverse types of disasters.Understanding disasters with these online maps has become an important research issue.In this article,we propose a map-based general-purpose emergency management support system based on a computational model of generalized(multiplicatively weighted,order-k,and Minkowski-metric)Voronoi diagrams.The proposed system tessellates Web maps and models disasters(or emergency response units)having different weights in the complete order from 1 to k-1 in the three popular Minkowski metrics(Euclidean,Manhattan,and Maximum distance)pro-vide insightful information for various what-if emergency scenarios.The proposed map-based emergency management support system systematically supports neighboring queries,districting queries,location optimization queries,and routing queries.We pro-vide specific examples to illustrate how our system supports these queries. 相似文献
84.
85.
Pilar Moreno-Regidor Jésus García López de Lacalle Miguel-Ángel Manso-Callejo 《International journal of geographical information science》2013,27(10):1811-1829
Territory or zone design processes entail partitioning a geographic space, organized as a set of areal units, into different regions or zones according to a specific set of criteria that are dependent on the application context. In most cases, the aim is to create zones of approximately equal sizes (zones with equal numbers of inhabitants, same average sales, etc.). However, some of the new applications that have emerged, particularly in the context of sustainable development policies, are aimed at defining zones of a predetermined, though not necessarily similar, size. In addition, the zones should be built around a given set of seeds. This type of partitioning has not been sufficiently researched; therefore, there are no known approaches for automated zone delimitation. This study proposes a new method based on a discrete version of the adaptive additively weighted Voronoi diagram that makes it possible to partition a two-dimensional space into zones of specific sizes, taking both the position and the weight of each seed into account. The method consists of repeatedly solving a traditional additively weighted Voronoi diagram, so that each seed's weight is updated at every iteration. The zones are geographically connected using a metric based on the shortest path. Tests conducted on the extensive farming system of three municipalities in Castile-La Mancha (Spain) have established that the proposed heuristic procedure is valid for solving this type of partitioning problem. Nevertheless, these tests confirmed that the given seed position determines the spatial configuration the method must solve and this may have a great impact on the resulting partition. 相似文献
86.
D.G. Turner 《Astronomische Nachrichten》2012,333(2):174-181
Existing photometry for NGC 2264 tied to the Johnson & Morgan (1953) UBV system is reexamined and, in the case of the original observations by Walker (1956), reanalyzed in order to generate a homogeneous data set for cluster stars. Color terms and a Balmer discontinuity effect in Walker's observations were detected and corrected, and the homogenized data were used in a new assessment of the cluster reddening, distance, and age. Average values of EB – V = 0.075 ± 0.003 s.e. and V0 –MV = 9.45 ± 0.03 s.e. (d = 777 ± 12 pc) are obtained, in conjunction with an inferred cluster age of ∼5.5 × 106 yr from pre‐main‐sequence members and the location of the evolved, luminous, O7 V((f)) dwarf S Mon relative to the ZAMS. The cluster main sequence also contains gaps that may have a dynamical origin. The dust responsible for the initial reddening towards NGC 2264 is no more than 465 pc distant, and there are numerous, reddened and unreddened, late‐type stars along the line of sight that are difficult to separate from cluster members by standard techniques, except for a small subset of stars on the far side of the cluster embedded in its gas and dust and background B‐type ZAMS members of Mon OB2. A compilation of likely NGC 2264 members is presented. Only 3 of the 4 stars recently examined by asteroseismology appear to be likely cluster members. NGC 2264 is also noted to be a double cluster, which has not been mentioned previously in the literature (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
87.
The near infrared range has opened a new window to study stellar populations in the Galaxy, in the Local Groud and beyond. Despite the large and growing use of these data, insufficient efforts have been made in the direction to calibrate stellar physical parameters such as age, reddening and distance. This can also be achieved using near infrared and optical data together. Furthermore, the huge amounts of photometric data available now and in the incoming years, demand the development of automated and statistical isochrone fittings to cope with such data. With this in mind, we analyse 2MASS data in order to determine physical parameters for a sample of 9 open clusters. As a first step, we determined the age, reddening and distance values for each cluster applying the classical isochrone fitting (by eye). Subsequently, we employed an automated procedure which compares synthetic colour-magnitude diagrams to observed ones, making use of the likelihood statistics to find the best solution. We also carried out structural analyses of the clusters using stellar radial density profiles. Both classical and statistical isochrone fittings revealed that there can be disagreement between physical parameters obtained from near infrared data analysis and the literature corresponding ones, most based on optical and UV data. Concerning the observed cluster structures, they were studied for the first time. We found evidence of various dynamical stages in the sample. 相似文献
88.
Journal of Geographical Sciences - Currently beach morphodynamic classification is the most important foundation to conduct associated coastal geomorphological studies. This paper carried out beach... 相似文献
89.
国际岩石力学学会建议了4种岩石I型断裂韧度(KIC)测试方法。将建议方法的人字形切槽巴西圆盘试样与直切槽半圆盘试样结合,可以得到具有诸多优点的人字形切槽半圆盘(CCNSCB)三点弯曲试样。近年来,CCNSCB方法受到许多关注,然而,其渐进破坏过程却尚未进行有效的评估。为此,对其进行了数值研究,其内容包括:进行细观损伤力学模拟,直观展现CCNSCB试样渐进断裂过程;考虑不同支撑跨距与直径之比( )的影响,发现 愈大,愈加符合测试原理,建议 取0.8;采用有限元子模型技术对CCNSCB方法( 0.8)中计算KIC的关键参数-临界无量纲应力强度因子( )进行了宽范围标定,可供相关研究直接查取;细观损伤力学模拟峰值力对应的临界裂纹与有限元标定 对应的临界裂纹较为一致,证明CCNSCB方法测试原理的合理性,以及数值模拟与 标定结果的有效性。 相似文献
90.
Temporal variations of the subsurface meridional flow with the solar cycle have been reported by several authors. The measurements
are typically averaged over periods of time during which surface magnetic activity existed in the regions where the velocities
are calculated. The present work examines the possible contamination of these measurements due to the extra velocity fields
associated with active regions plus the uncertainties in the data obtained where strong magnetic fields are present. We perform
a systematic analysis of more than five years of GONG data and compare meridional flows obtained by ring-diagram analysis
before and after removing the areas of strong magnetic field. The overall trend of increased amplitude of the meridional flow
towards solar minimum remains after removal of large areas associated with surface activity. We also find residual circulation
toward the active belts that persists even after the removal of the surface magnetic activity, suggesting the existence of
a global pattern or longitudinally-located organized flows. 相似文献