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91.
Learning knowledge graph (KG) embeddings is an emerging technique for a variety of downstream tasks such as summarization, link prediction, information retrieval, and question answering. However, most existing KG embedding models neglect space and, therefore, do not perform well when applied to (geo)spatial data and tasks. Most models that do consider space primarily rely on some notions of distance. These models suffer from higher computational complexity during training while still losing information beyond the relative distance between entities. In this work, we propose a location‐aware KG embedding model called SE‐KGE. It directly encodes spatial information such as point coordinates or bounding boxes of geographic entities into the KG embedding space. The resulting model is capable of handling different types of spatial reasoning. We also construct a geographic knowledge graph as well as a set of geographic query–answer pairs called DBGeo to evaluate the performance of SE‐KGE in comparison to multiple baselines. Evaluation results show that SE‐KGE outperforms these baselines on the DBGeo data set for the geographic logic query answering task. This demonstrates the effectiveness of our spatially‐explicit model and the importance of considering the scale of different geographic entities. Finally, we introduce a novel downstream task called spatial semantic lifting which links an arbitrary location in the study area to entities in the KG via some relations. Evaluation on DBGeo shows that our model outperforms the baseline by a substantial margin.  相似文献   
92.
Noble and active gases are released from geological samples during gas extraction for noble gas isotope analyses. The active gases should be removed before inletting to mass spectrometers for the analyses. The normal noble gas preparation systems can clean up most geological samples. However, authigenic minerals from sedimentary rocks in oil/gas fields contain organic matter, which cannot be cleaned up by the normal preparation systems and thus influence the noble gas analyses. We introduce a novel gas purification system(PRC patent No. ZL201320117751.2), which includes several reversible purification pumps with different absorbing and degassing temperatures. It can well clean up water steam, carbon dioxide and organic gases. Mica minerals are often used for ~40Ar/~39 Ar dating. A muscovite sample(2082MS) which could not be cleaned up by the normal preparation system with two SAES NP10~#174; getters, becomes the test sample for a comparative experiment in this study. The experiment is assigned into 4 sections with the organic gas removal system(OGRS) "Closed/Opened" in turn. When the OGRS is closed only with two NP10 getters for purification, the ~40Ar intensities increase in curves with inlet time because of impurities, the ~40Ar/~39 Ar dating results yield age errors about ±2%–±1%(2σ). When the OGRS is opened for purification, in contrast, the ~40 Ar intensities decrease linearly with inlet time. This indicates that the gases have been cleaned up effectively, and the 4~0Ar/~39 Ar results yield ages with errors in ±0.4%. The OGRS is very helpful to obtain high-quality analysis data.  相似文献   
93.
Lao Guoli 《岩土力学》1988,9(4):51-61
This paper from the point of regional, based on the statistics and analyses on a great number of geotechnical test, deals with the geneses and composition of Hainan soils and the distribution law of various soils in the Hainan Island, the physico-mechanical properties of the soils are also discussed in the paper. All this is the summary on the work during the past three decades. The research results listed in the paper can be used to a certain extent as a reference for the development of the Hainan Island.  相似文献   
94.
南海西南海域的内波和细结构   总被引:9,自引:1,他引:9  
根据1990年初夏南海西南部水域的两个连续站CTD和多层海流计资料及50多个大面站CTD资料的分析研究得到一些关于此海域的内波和细结构的特性。它包括等温、盐、密度面起伏的特性,盐度双跃层和逆盐层等长存性细结构、温度Cox数的概率密度函数及流速频谱的特性,Cox数和温度脉动垂向波数谱的一般品性及其随水层和地域的变化规律等诸方面。  相似文献   
95.
北部湾入海河流营养盐的分布特征及入海通量研究   总被引:1,自引:1,他引:1  
于2018年2月(枯水期)和8月(丰水期)对南流江、大风江、钦江、茅岭江和防城江等北部湾主要的入海河流开展调查,分析这些河流各形态营养盐的浓度特征及入海通量。结果表明,不同时期营养盐浓度差异较为明显,主要表现为枯水期防城江、茅岭江和钦江的营养盐浓度较丰水期高,而丰水期大风江和南流江的营养盐浓度高于枯水期,表明丰水期大风江和南流江污染较为严重。丰水期,${\rm {NO}}_3^- $是溶解态无机氮的主要成分,但枯水期防城江和大风江${\rm {NH}}_4^+ $比例升高。根据径流量资料和河流营养盐浓度,估算出2018年北部湾入海河流的氮和磷的入海通量分别为1014607 t和47929 t,其中溶解态无机氮占总氮的77%,${\rm {PO}}_4^{3-} $占总磷的40%。丰水期,南流江营养盐入海通量总体较高,其次是大风江,防城江、茅岭江和钦江的营养盐入海通量相对较小。枯水期,受区域污染影响,不同河流营养盐的入海通量变化较大。与历史对比,北部湾河流的营养盐入海通量显著升高,表明河流营养盐输入的升高可能是北部湾近海水体富营养化加重的重要因素。北部湾河流不同时期氮和磷输入量的差异,可能会对北部湾近岸及邻近海域生态系统产生较大影响。  相似文献   
96.
In certain regions,submarine groundwater discharge(SGD) into the ocean plays a significant role in coastal material fluxes and their biogeochemical cycle;therefore,the impact of SGD on the ecosystem cannot be ignored.In this study,SGD was estimated using naturally occurring radium isotopes(~(223)Ra and ~(224)Ra) in a subtropical estuary along the Beibu Gulf,China.The results showed that the Ra activities of submarine groundwater were approximately 10 times higher than those of surface water.By assuming a steady state and using an Ra mass balance model,the SGD flux in May 2018 was estimated to be 5.98×10~6 m~3/d and 3.60×10~6 m~3/d based on ~(224)Ra and ~(223)Ra,respectively.At the same time,the activities of Ra isotopes fluctuated within a tidal cycle;that is,a lower activity was observed at high tide and a higher activity was seen at low tide.Based on these variations,the average tidal pumping fluxes of SGD were 1.15×10~6 m~3/d and 2.44×10~6 m~3/d with ~(224)Ra and ~(223)Ra,respectively.Tidaldriven SGD accounts for 24%-51% of the total SGD.Therefore,tidal pumping is an important driving force of the SGD in the Dafengjiang River(DFJR) Estuary.Furthermore,the SGD of the DFJR Estuary in the coastal zone contributes significantly to the seawater composition of the Beibu Gulf and the material exchange between land and sea.  相似文献   
97.
劳国利 《岩土力学》1988,9(4):51-61
本文对以往三十来年的工作进行了总结,在统计和分析大量的土工试验资料的基础上,从区域土质学的观点出发,研究了海南岛土类的成因、成份及各种土类的分布规律,探索了各类土的物理力学特性。文中所列的海南岛各种土类的物理力学试验研究成果,对今后海南岛的进一步开发有一定的参考价值。  相似文献   
98.
Microbial communities flourish at gas hydrate occurrences in ocean sediments. Studies are reported in this paper on the laboratory production, separation, characterization and hydrate catalysis of biosurfactants from cultures of the Bacillus subtilis bacterium associated with Gulf of Mexico gas-hydrate accumulations. The B. subtilis bacterium from ATCC 21332 species was cultured anaerobically with glucose as carbon-source to produce surfactin, one of the more potent surface active agents known. The surface-active agent was removed from the broth in foam created by bubbling inert gas through the mixture, and biosurfactant was then recovered from the collapsed-foam distilled water solution by acid precipitation and dichloromethane extraction. According to HPLC spectra, five surfactin isomers were identified in the sample of laboratory-generated biosurfactant. Recovered surfactin was then used to perform gas-hydrate formation studies in porous media saturated with the surfactin-water solution. Gas-hydrate induction time and formation rate determinations showed that the anaerobically-produced biosurfactants catalyzed hydrate formation markedly. The tests suggest prolific surfactin production by the B. subtilis bacterium and of other species under prevailing anaerobic conditions around seafloor gas hydrates that promotes hydrate formation and the propensity of the bioproduct to be dispersed in the porous media by natural gas vents.  相似文献   
99.
介绍瑞士ARL8680型X射线荧光光谱仪在更换高压发生器后出现的故障现象、原因及处理方法。  相似文献   
100.
雅鲁藏布江断裂带的形成   总被引:3,自引:2,他引:3  
雅江断裂带①主要由4条断层组成3个向西南突出的巨大弧形断裂带。晚三叠世至第四纪,雅江断裂带都有沉积地层发育,从西北向东南,各弧形断裂带成为相继接受沉积的坳陷区,而同一时期,与之紧邻的南北两盘却为隆升区。雅江断裂带,正是在该区地壳多次层波运动中形成的。  相似文献   
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