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121.
XIE Guiqing MAO Jingwen HU Ruizhong LI Ruiling JIANG Guohao CAO Jinjian ZHAO Junhong State Key Laboratory of Geological Process Mineral Resourses China University of Geosciences Beijing Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing Institute of Geochemistry Chinese Academy of Sciences Guiyang Guizhou Earth Science Department Sun Yat-Sun University Guangzhou Guangdong 《《地质学报》英文版》2005,79(5):662-672
Geochemical and isotopic investigations have been carded out on the Chebu gabbroite in southern Jiangxi Province, southeast China and these results are compared with gabbro bodies along the coast of Fujian Province in order to understand their magma sources and tectonic implications. The Chebu intrusion formed at the beginning of the Middle Jurassic (172~4.3 Ma). These rocks are Ti-rich and Al-poor in major elements, characterized by strong enrichment in large-ion lithophile elements (LILE) and moderate enrichment in high field strength elements (HFSE) and light rare-earth elements CLREE), without pronounced Nb or Ta anomalies. Age-correlated Sr-Nd isotope ratios show moderately high ranges of (^87Sr/^86Sr)i from 0.7065 to 0.7086 and 0.5124 to 0.5125 of (^143Nd/^144Nd)i. The geochemical characteristics of the Chebu gabbroite suggest that it is notably different from island-arc basalt and similar to intra-plate basaltic rocks. By combining interpretations of its geological and geochemical characteristics and the regional geological development history, the Chebu gabbroitic intrusion is thought to be the product of asthenosphere upwelling and rapid lithosphere extension during a transition of tectonic systems in southeast China. The tectonic environment and source characteristics of the intrusion are different from Cretaceous gabbro bodies along the coast of Fujian Province, The former formed in a tectonic environment of rapid intra-plate lithospheric extension and the source characteristics were of a weakly enriched primitive mantle, whereas the latter originated mainly in a volcanic-magmatic arc extensional tectonic environment and the nature of the source was an enriched mantle with more subduct subducted components. 相似文献
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三维激光雷达(Light Detection and Ranging,LiDAR)系统通过发射和接收激光脉冲,能直接快速获得地表密集的高精度3维激光点云数据,以下简称LiDAR激光点云数据.本文应用车载LiDAR激光点云移动测量技术,结合房产测量系统及测区实际情况,对不动产测绘项目外业数据采集过程进行研究,并详细阐述了利用点云进行不动产外业测量的方法,最后与传统测图方法进行比较.结果表明,车载LiDAR激光点云移动测量技术可以满足不动产测绘的精度要求,而且外业数据采集效率较传统方法提高30多倍.可以为不动产测绘项目生产提供参考和借鉴. 相似文献
124.
The adsorption capacity and thermodynamic properties of high-rank tectonically deformed coal (TDC) samples from the Yangquan coalfield in North China were analyzed by combining isothermal adsorption and Polanyi potential theory. The adsorption capacities of mylonitic- (10.7015–17.2065 cm3/g) and scaly (9.8237–11.5386 cm3/g) coals are higher than those of cataclastic- (8.3496–9.5238 cm3/g) and schistose (7.7990–8.0467 cm3/g) coals. The primary- and wrinkle coals have the lowest adsorption capacities. The adsorption potential (the change of surface free energy per mole during physical adsorption) decreases with the increasing adsorption space in a parabola characteristic. For different TDCs, the interval length of the adsorption potential distribution is in the same order with the adsorption capacity. The interval lengths of primary-, schistose-, and mylonitic coals are 0–0.014, 0–0.020, and 0–0.025 cm3/g, respectively. The reduction amounts of surface free energy for mylonitic- (6.040–10.082 kJ/cm2) and scaly (2.075–6.047 kJ/cm2) coals are higher than those of the cataclastic- (3.069–4.249 kJ/cm2) and wrinkle (2.222–3.434 kJ/cm2) coals. The initial and saturated adsorption surface free energies of mylonitic- and scaly coals are higher than those of the primary- and schistose coals. Based on the difference in the surface free energy reduction values, the TDCs, especially the mylonitic- and scaly coals, have a greater adsorption potential than primary- and other TDCs. 相似文献
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127.
Guangliang Zhang Junhong Bai Jia Jia Xin Wang Wei Wang Qingqing Zhao Shuai Zhang 《中国地理科学(英文版)》2018,28(3):374-385
Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native (Suaeda salsa) and invasive (Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon (SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents (g/kg) and stocks (kg/m2) were significantly increased (P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer (0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios (LnRR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase (2–4 years in this study) due to the negative LnRR values, especially for 20–60 cm depth. And the SOCD in surface layer (0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer (Adjusted R2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes. 相似文献
128.
Jia Jia Junhong Bai Wei Wang Guangliang Zhang Xin Wang Qingqing Zhao Shuai Zhang 《中国地理科学(英文版)》2018,28(3):411-419
Little information is available on biogenic elements (carbon, nitrogen, phosphorus and sulfur) and the ecological stoichiometric characteristics of plants in coastal wetlands. To investigate the contents of carbon, nitrogen, phosphorus and sulfur of plants, and their ecological stoichiometric characteristics in the Yellow (Huanghe) River Delta, plant samples were collected from two typical salt marshes (Suaeda salsa and Phragmites australis wetlands) during the period of from August to October in 2007, and the ratios of C/N, C/P, N/P, C/N/P and C/N/P/S were calculated. Results showed that during the studying period, plant C, N and P were lower than the global average values, and plant N and P were lower than the China’s average values. Leaf C and S in Suaeda salsa were significantly lower than those in Phragmites australis (P < 0.05), and leaf N and P in Suaeda salsa and Phragmites australis showed no significant differences (P > 0.05). Average C/N ratios were 23.75 in leaf, 73.36 in stem, 65.67 in root of Suaeda salsa, and 33.77 in leaf, 121.68 in stem, 97.13 in root of Phragmites australis. Average C/N ratios of Suaeda salsa and Phragmites australis were all great than 25, indicating the salt marsh in the Yellow River Delta is an N limitation system. Average C/P ratios were 276.78 in leaf, 709.28 in stem and 1031.32 in root of Suaeda salsa, and 536.94 in leaf, 768.13 in stem and 875.22 in root of Phragmites australis. The average N/P ratios of Suaeda salsa were 12.92 in leaf, 10.77 in stem and 10.91 in root, and the average N/P ratios of Phragmites australis were 16.40 in leaf, 7.40 in stem and 6.92 in root, indicating the Suaeda salsa wetlands were N limited and Phragmites australis wetlands were N limited in August and P limited in October in 2007. The average C/N, C/P and C/N/P ratios in Suaeda salsa and Pragmites australis were higher than the global average values, indicating the lower quality of organic matter provided by wetland plants in the Yellow River delta. 相似文献
129.
YANG Weifeng CHEN Min CAO Jianping QIU Yusheng ZHANG Run MA Qiang TONG Jinlu YANG Junhong YANG Zhi L E 《海洋学报(英文版)》2009,28(2):45-53
Thorium-234 and particle composition (organic matter, biogenic silica, carbonate and lithogenic component) were examined in the East China Sea (ECS) and the northern South China Sea (NSCS) in order to constrain the particle types scavenging thorium isotopes. Good positive correlations between particulate organic matter (POM) or carbonate and thorium-234 in suspended particulate matter (SPM) indicates that POM and carbonate are efficient to scavenge thorium-234. No relationship between biogenic silica and thorium-234 suggests that geochemical behavior of thorium-234 may be not influenced by biogenic silica. A simple model was used to evaluate the affinity of thorium-234 to different particle components. The results show that POM is the most efficient scavenger for thorium-234 in the ECS and the NSCS, followed by carbonate. The authors'' results lend support to the utility of thorium-234 as a proxy of POC and carbonate in the upper layer. However, the strong dependence of thorium scavenging on particle composition challenges thorium-230 as a constant flux proxy. 相似文献
130.
内陆盐沼湿地土壤碳氮磷剖面分布的季节动态特征 总被引:9,自引:0,他引:9
本文以向海湿地为例探讨了内陆盐沼湿地土壤剖面中碳氮磷等生源要素的季节动态变化特征及其影响因素.结果表明,内陆盐沼湿地土壤中有机碳、全氮和全磷含量与土壤深度之间存在显著负相关,在剖面中均表现为由表层向下层其含量不断减少的趋势,且具有明显的季节波动特征,除表层土壤碳氮含量随季节变化呈持续增加外,生源要素剖面分布的季节变化基本表现为先减少后增加的趋势.有机碳、全氮和全磷含量之间关系密切,且三者受土壤粒度的影响都非常显著.土壤pH值仅与土壤有机碳之间存在显著的相关关系,而对全氮和全磷含量的影响则不显著. 相似文献