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71.
The equilibrium and kinetic adsorption of phosphate (P) from the Yellow River water onto desert particles taken from the Ulan Buh and Kubuqi deserts were investigated. Effect of the initial concentration of P and particulate matter on the sorption was explored. The kinetic studies show that adsorption rate was faster within the 0–8th hour period, then gradually decreased at 8th–48th hour period and basically tended to a dynamic equilibrium at the 48th hour, but there exists an adsorption difference of P onto different desert particles. The uptake process of P followed the pseudo-second-order rate model and the Morris-Weber diffusion equation which indicates that the adsorption process was mainly controlled by P diffusion inside the particles. The equilibrium investigation obtained an adsorption-desorption equilibrium mass concentration (EPC0) of P from the Yellow River water on desert particles with the range of 0.010–0.042 mg/L, which is higher than present P concentration in the Yellow River. This study indicates that desert particles entering the river might release P to the Yellow River. 相似文献
72.
六股水磷矿床赋存于下寒武统麦地坪组,包含2个磷矿层、6个磷矿体。矿体水平延伸1200~2700m,均厚1.3~4.88m,深部延深大于120m。矿石类型有块状及白云质条带(条纹)状2种磷矿石,P2O5平均品位29.42%。稀土元素总量低,分布模式呈轻稀土富集型。矿床为生物化学沉积成因,磷经历了复杂的富集过程。 相似文献
73.
Martha W. Gilliland 《Mathematical Geology》1976,8(3):219-242
Present ionic concentrations of Ca
++,HCO
3
-
,and HPO
4
=
in surface and groundwater runoff in Florida indicate that phosphorus is being concentrated in rock through dissolution and reprecipitation, with calcium phosphate increasing at the expense of calcium carbonate. Analog computer simulation of a systems model of this process suggests that significant enrichment can occur in 20 million years. The degree of enrichment depends on the supply of new phosphorus to Florida through rain and oceanic exchange processes. If the calcium phosphate content of original rock is 0.5 to 1.0 percent (0.52 to 1.05 percent P
2
O
5),a formation with 10 to 20 percent calcium phosphate (CaPO
4
or 10.5 to 21.0 percent P
2
O
5)as in the Hawthorn Formation (Miocene)may result. Nutrient upwelling along the continental slope coupled with transport to the estuaries by lateral eddy diffusion can supply an additional 400 mg P|m
2
|yr which, if deposited, would result in a sediment with a 4.3 percent CaPO
4 (4.5 percent P
2
O
5)content. If this is enriched later by resolution, 40 percent CaPO
4 (42 percent P
2
O
5)results. Through geologic time, the ocean may be considered as a source of phosphorus to the land through rain or estuarine sediment. 相似文献
74.
P. F.?SchofieldEmail author K. S.?Knight J. A. M. van der?Houwen E.?Valsami-Jones 《Physics and Chemistry of Minerals》2004,31(9):606-624
The unit-cell and atomic parameters of perdeuterated brushite have been extracted from Rietveld analysis of neutron powder diffraction data within the temperature range 4.2 to 470 K. The thermal expansion of brushite is anisotropic, with the largest expansion along the b axis due principally to the effect of the O(1)···D(4) and O(3)···D(2) hydrogen bonds. Expansion along the c axis, influenced by the Ow1···D(5) interwater hydrogen bond, is also large. The high temperature limits for the expansion coefficients for the unit-cell edges a, b and c are 9.7(5) × 10–6, 3.82(9) × 10–5 and 5.54(5) × 10–5 K–1, respectively, and for the cell volume it is 9.7(1) × 10–5 K–1. The angle displays oscillatory variation, and empirical data analysis results in = 1.28(3) × 10–6sin(0.0105 T) K–1, within this temperature range. The evolution of the thermal expansion tensor of brushite has been calculated between 50 T 400 K. At 300 K the magnitudes of the principal axes are 11 = 50(6) × 10–6 K–1, 22 = 26.7(7) × 10–6 K–1 and 33 = 7.0(5) × 10–6 K–1. The intermediate axis, 22, is parallel to b, and using IRE convention for the tensor orthonormal basis, the axes 11 and 33 have directions equal to (–0.228, 0, –0.974) and (–0.974, 0, 0.228) respectively. Under the conditions of these experiments, the onset of dehydration occurred at temperatures above 400 K. Bond valence analysis combined with assessments of the thermal evolution of the bonding within brushite suggests that dehydration is precipitated through instabilities in the chemical environment of the second water molecule. 相似文献
75.
Sediment diffusive fluxes of Fe,Mn, and P in a eutrophic lake: Contribution from lateral vs bottom sediments 总被引:3,自引:0,他引:3
Nelson Belzile Jaime Pizarro Montserrat Filella Jacques Buffle 《Aquatic Sciences - Research Across Boundaries》1996,58(4):327-354
Water column data and porewater profiles are used to study the chemical evolution with time and with depth of a eutrophic lake. By using different approaches, diffusion fluxes for dissolved iron, manganese and phosphate are calculated and used to describe the processes occurring at the sediment-water interface as well as in the hypolimnion of the lake. These data are used in the elaboration of a qualitative model to describe the chemical behaviour of the sedimentary interface of an anoxic lake with emphasis on the Fe/P/S system. Acorona model is proposed to explain the evolution with time of the diffusion process by estimating the relative contribution of bottom and lateral sediment surfaces to the total fluxes of dissolved elements diffusing from the sediment to the overlying water. As the hypolimnion becomes more anoxic, it has been observed that lateral sediment surfaces (16 to 10 meters in depth) represents a larger supplier of diffusing dissolved components than the bottom sediment portion (bottom to 18 meters). 相似文献
76.
东野脉兴 《吉林大学学报(地球科学版)》1989,(2)
中国北方早、中前寒武系磷矿有四个层位六种类型。太古代磷矿主要产于中朝地块内的华北陆核、辽吉南部—朝鲜北部陆核及山东陆核等陆核区。早元古代早期,在太古代陆核边缘或中间地块沉积了优地槽型磷矿。早元古代晚期有大陆边缘和拗拉槽白云质碳酸盐建造的磷矿床与克拉通内盆地陆屑和复理石建造的磷矿床,其中大陆边缘型最重要,构成了长约4000多公里的巨大“S”形成矿带。早元古代末期,五台运动之后,有同造山期的山间盆地磷矿床形成。 相似文献
77.
78.
报道了以NH4H2PO4为基体改进剂,采用悬浮体制样石墨炉原子吸收光谱法直接测定琥珀中微量铅的方法。试验了影响测定的主要因素。在优化实验条件下。方法的检出限为0.038μg/g,Pb的质量浓度为0~80μg/L时,工作曲线线性关系良好。对于ω(Pb)=5.71μg/g样品的测定,相对标准偏差(RSD,n=5)为6.83%。 相似文献
79.
磷酸盐缓凝剂的优选与水泥复合浆液性能研究 总被引:3,自引:0,他引:3
研制了一种以无机聚合物(水玻璃)为速凝剂,以磷酸盐为缓凝剂配制而成的CWP水泥复合浆液。在该复合浆液中,用磷酸二氢铵作缓凝剂效果最好。CWP复合浆液在流变性,塑性强度,稳定性和结石强度上具有优良的性能。 相似文献
80.
柱撑蒙脱石改性磷铵及其增效机理研究 总被引:1,自引:0,他引:1
本通过Keggin离子制备了柱撑蒙脱石,并对其进行了酸化处理。盆栽试验研究表明,利用柱撑蒙脱石和酸化柱撑蒙脱石对磷酸二铵进行改性试验处理,生物量显高于磷铵对照,氮素和磷素利用率显提高。X射线衍射技术和红外光谱对改性磷铵进行结构研究表明,其晶体结构发生了较大的变化,这种变化减少了氮的损失和磷在土壤中的固定,从而提高磷铵氮磷的生物有效性。 相似文献