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981.
Based on the study of Beijing PM10 bioreactivity with the newly developed plasmid DNA assay method, and analysis for trace elements of PM10, the cause of plasmid DNA damage by PM10 was investigated. The study showed that plasmid DNA oxidative damages by PM10 are of difference in different seasons at various areas. The concentrations of TM50 of PM10 in whole samples respectively collected at urban and comparison sites during winter were 900 μg mL?1 and 74 μg mL?1, while those in their corresponding soluble fractions were 540 μg mL?1 and 86 μg mL?1. In contrast, TM50 contents of PM10 from summer whole samples at urban areas and comparison sites were 116 μg mL?1 and 210 μg mL?1, whereas those in their soluble fractions were 180 μg mL?1 and 306 μg mL?1. The difference of bioreactivity of Beijing PM10 resulted from the variation of trace elements. The oxidative damage of plasmid DNA caused by Pb, Zn, As in PM10 (whole sample) was relatively strong. TM50 and Mn, V, Zn display stronger correlation in the soluble fraction. It implies that Zn could be the major trace element in Beijing PM10 which contributes to oxidative damage to plasmid DNA. 相似文献
982.
A dolerite sill cutting slightly older basalt in west-central Sweden shows a strong chemical variation (54% < SiO2 < 73%) within a restricted area (< 100 × 100 m2). The linear correlation among almost all elements is extremely high; in addition, NdT is strongly correlated with the SiO2 content. Least-square hyperbolic-ratio and three-element ratio modelling (common denominator) suggests that most of the chemical variation is explained by mixing and/or micro-mingling. In all, we test 407 hyperbolas, of which 402 are fitted. The five ratio pairs, which could not be fitted to a hyperbola using a least-square fitting procedure, have the ratio Th / Eu in common. Testing the goodness of fit is problematic for hyperbolic distributions; for comparing purposes we sum the distances to chords approximating the hyperbola. Mobile and immobile elements behave similarly, suggesting that no elements are lost or added from outside the system. The data suggests that already the most mafic of the analysed rocks is a mixture of the ‘normal’ dolerite and a siliceous crustal rock. A mafic magma intruded into the base of the crust, where it fractionated resulting in a decreased Mg number. The magma was then contaminated with country rocks in an intermediate magma chamber due to country rock melting; during mixing/mingling almost no fractionation took place. The contaminated rock suggests the presence of a fluid phase. This was probably a prerequisite for country-rock melting. Enrichment in some incompatible elements suggests that besides major mixing/mingling a thermochemical separation process has affected the most felsic rock enriching it in light rare earths and Zr. 相似文献
983.
984.
E. B. Volynets 《Stratigraphy and Geological Correlation》2006,14(2):200-210
Taxonomic composition of plant fossils from the Aptian-Cenomanian sediments of the Alchan, Razdol’naya, and Partizanskaya depressions of Primor’e is studied in detail. Each of the established floral assemblages characterizes a particular stage of flora stabilization. Correlation of the assemblages is performed. Floral assemblages of the Alchan depression, which occur in association with macrofauna, are suggested to be the standard ones for the southern Far East. New species are described. 相似文献
985.
Application of grey correlation method to evaluate potential groundwater recharge sites 总被引:1,自引:1,他引:1
H. S. Gau C. Y. Hsieh C. W. Liu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,20(6):407-421
Artificial recharge is a practical tool available for increasing the groundwater storage capacity. The efficiency of artificial recharge is related to various hydrogeological factors of the target area. In this study, a variable saturated groundwater flow model, FEMWATER, was used to evaluate the arrival times of recharged water that infiltrates from an artificial recharge pond to the groundwater table under various hydrogeological conditions. Forty-five arrival times were generated by FEMWATER. The relationships between the arrival times and hydrogeological factors used in the simulation of FEMWATER were analyzed by the grey correlation method. The results show the order of importance of the factors as they influence the arrival time. In order from high to low importance, they are α, D
g, θ e, D
p, K
S and β. D
g and D
p are interpreted as the potential for movement of the recharge water; θe is the water storage capacity of soil, and K
S represents the ability of soil to transport water. α and β describe the characteristic curve of the unsaturated soil. The method was applied to evaluate a suitable site for artificial recharge in the Yun-Lin area. Grey correlation analysis was performed to obtain the grey correlation grade using the minimum arrival time as a reference sequence. An index is proposed herein to determine the recharge efficiency of 20 sampling sites. A contour mapping of index values at the 20 sampling sites identified three areas for artificial aquifer recharge in Yun-Lin. Area A in the upper plain is considered more appropriate for groundwater recharge than areas B and C in the coast. 相似文献
986.
Keith A. Horton Glyn Williams-Jones Harold Garbeil Tamar Elias A. Jeff Sutton Peter Mouginis-Mark John N. Porter Steven Clegg 《Bulletin of Volcanology》2006,68(4):323-327
A miniaturized, lightweight and low-cost UV correlation spectrometer, the FLYSPEC, has been developed as an alternative for
the COSPEC, which has long been the mainstay for monitoring volcanic sulfur dioxide fluxes. Field experiments have been conducted
with the FLYSPEC at diverse volcanic systems, including Masaya (Nicaragua), Poás (Costa Rica), Stromboli, Etna and Vulcano
(Italy), Villarica (Chile) and Kilauea (USA). We present here those validation measurements that were made simultaneously
with COSPEC at Kilauea between March 2002 and February 2003. These experiments, with source emission rates that ranged from
95 to 1,560 t d−1, showed statistically identical results from both instruments. SO2 path-concentrations ranged from 0 to >1,000 ppm-m with average correlation coefficients greater than r
2=0.946. The small size and low cost create the opportunity for FLYSPEC to be used in novel deployment modes that have the
potential to revolutionize the manner in which volcanic and industrial monitoring is performed. 相似文献
987.
北极海冰和北半球500hPa极涡的相互关系 总被引:7,自引:0,他引:7
利用NCEP/NCAR 2.5°×2.5°的500 hPa高度场月平均再分析资料和1°×1°的海冰资料分别计算了北半球500 hPa极涡面积、极涡强度指数和北极海冰面积指数,分析了它们的经向分布、周期变化以及长期变化趋势中的突变。结果表明,海冰和极涡在经向分布上有明显差异,就东西半球而言它们的相对位置也不一样。除了都具有4个月、准半年、准1 a、4~5 a和10 a的共同周期外,还呈现出各自的周期变化。北极海冰面积自20世纪80年代以来呈明显减小趋势,北半球极涡面积也呈减小趋势,但是它们发生突变的时间却完全不同。海冰与极涡面积有显著的正相关关系,但海冰和极涡强度、极涡面积和极涡强度之间的关系却纷繁复杂。 相似文献
988.
989.
贵州省金沙煤田龙潭组岩煤层测井对比方法 总被引:2,自引:0,他引:2
龙潭组是金沙井田的主要含煤地层,含煤达12~15层,其中7、8、9、11、12五层煤较稳定,为主要可采煤层。根据测井物性曲线与地质岩心的对比分析,总结出该组煤岩层的共有测井物性规律:低密度、中低电阻率、较高中子孔隙度和较低的纵波速度,以及其特有规律如:5、6、7、8、9煤层的低自然伽马,11、12煤层较高的自然伽马等特征。结合煤层测井曲线形态特征及其与顶、底板以及和煤层上、下标志层间组合关系,进行了全煤系地层的对比,揭示了该井田煤层的分岔、合并、冲刷、沉缺、煤层厚度等变化规律。 相似文献
990.
凡在风化壳红土形成过程中形成,并保留至今的具有工业价值的各类矿床,均可称其为“红土型矿床”。铁、钛、金、锡、钴等云南红土型矿床,易采治(湿法),其基岩岩性与矿化虽差异甚大,但其最终形成的含矿红土,化学性质却较为接近。 相似文献