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991.
992.
新疆04井水位突降异常的机理分析 总被引:3,自引:3,他引:0
通过04井地下不动力学条件和地球化学环境的综合分析,探讨了井水位突降异常变化的基本特征和相邻两并含水层孔隙压力动态的关系及相互作用过程。4b井喷(溢)水卸压是04井水位突降的直接原因。当04井的水位升高,水头高度达到并超过4b井井口的高度时,4b井开始喷水卸压,水头损失造成孔隙压力的降低而形成降落漏斗,造成04井水位突然下降,一旦4b井喷水停止,04井水位又开始上升并逐步恢复到正常水位高度。在04井水位持续突降变化阶段,可通过统计突降过程参数(如突降发生的频度、两次突降异常之间的时长等)判别地震前兆异常。 相似文献
993.
文章总结矿产资源补偿费开征以来存在的主要问题,根据有关法规和征管工作的发展现状,提出了一些对策和建议。 相似文献
994.
通过1992年~1994年在永昌电厂粉煤灰场试验研究,分析了粉煤灰独特的理化性质,从风蚀的角度探讨了其危害的成因和特点,并提出了草障与植物相结合的粉煤灰综合治理措施.关键词 相似文献
995.
Yaroslaw A. Ilyushin 《Planetary and Space Science》2004,52(13):1195-1207
The propagation of electromagnetic waves in the northern polar ice sheet of Mars is considered. It is shown that the dispersion and attenuation of radio waves in the polar sheet are regulated by two groups of factors: the physical and chemical composition of the ice, and the geometrical parameters of the layered structure of polar sheet. Both analytical and numerical simulations of ultra wide band chirp radar pulse propagating through the cap are performed. Wide variety of combinations of the physical and geometrical parameters of the ice sheet, consistent with previously published observational data, has been considered. The frequency bands of transparency and opacity of the northern ice sheet for radar signals were found. The side clutter for this particular region of the planet is studied. 相似文献
996.
997.
A new approximation in determination of zonation boundaries of ignimbrite by ground penetrating radar: Kayseri,Central Anatolia,Turkey 总被引:1,自引:1,他引:0
Ground penetrating radar (GPR) method is used as a tool to identify the zonation boundaries in ignimbrite series through their
columnar section. Ignimbrites can be classified in terms of welding degree, colour, texture and mineralogical compositions.
The research area comprises a part of İncesu (Kayseri) ignimbrite at Central Anatolia, Turkey. This ignimbrite is divided
into three levels and each level has clear differences in terms of macroscopic and microscopic views. This paper presents
the results of an application of GPR for the determination of zonation boundary within the ignimbrite flow unit in the view
of their textural and petrological features. RAMAC CU II equipment was used with 250 MHz shielded antenna on parallel ten
profiles to observe the physical difference among the ignimbrite levels of the study area. Two levels out of three have been
defined at the İncesu ignimbrite and supported by field geology and petrographical studies. The first level, which is extremely
fractured structure, is about 1.5 m thick and matches with middle level of the İncesu ignimbrite. The second level has an
average 50–75 cm thickness and matches with lower level of the ignimbrite. In this manner, vertical lithological variations
should be taken into consideration during petrological investigation of the ignimbrites. 相似文献
998.
Modeled impacts of changes in tundra snow thickness on ground thermal regime and heat flow to the atmosphere in Northernmost Alaska 总被引:2,自引:0,他引:2
Seasonal snow covers the tundra surface for up to nine months of each year on the Alaskan North Slope. Variations in the snow thickness could strongly influence the thermal regime of the underlying soil and permafrost, and the surface energy balance. The impacts of increases and decreases in the tundra snow thickness on the thermal regime of snow surface, active layer, and permafrost, and on the conductive heat flow to the atmosphere were investigated numerically, by using an improved surface energy balance approach based one-dimensional heat transfer model. The baseline inputs for the numerical model are mean daily meteorological data and surface albedos collected at Barrow, Alaska from 1995 through 1999. Based on a study for the long-term mean daily maximum and minimum snow thickness distributions at Barrow in the snow season of 1948 through 1997, a snow thickness factor was defined and five simulation cases were run for the snow season of 1997–1998 by changing the snow thickness factor. The modeled results indicate that changes in snow thickness have significant impacts on ground thermal regimes and conductive heat flow to the atmosphere. Decreasing the snow thickness by 50% led to the maximum ground temperature decrease of 1.48 °C at 0.29 m depth, and 0.72 °C at 3.0 m depth; the magnitude of the mean conductive heat flow to the atmosphere for December increase of 4.3 Wm− 2. Increasing the snow thickness by 50% resulted in the maximum ground temperature increase of 1.44 °C at 0.29 m depth, and 0.66 °C at 3.0 m depth; the magnitude of the mean conductive heat flow to the atmosphere for December decrease of 1.57 W m− 2. On an annual basis, variation in the snow thickness by 50%, the ground temperature variations of more than 0.25 °C occurred as deep as 8.0 m below the ground surface. The modeled results also show that changes in snow thickness have a relatively small influence on the snow surface temperature. 相似文献
999.
This paper provides a proof of the symmetry of the equivalent transmissivity tensor computed with a method based on the solution
of the balance equation at the fine scale with integrated finite differences. The basic hypotheses are that the balance equation
is solved on a block assigning Dirichlet boundary conditions that vary linearly with the space coordinates and the equivalent
transmissivity tensor is computed as the linear tensor relating average flux and hydraulic gradient. 相似文献
1000.
B. G. Katz 《水文研究》1989,3(2):185-202
During 1983 and 1984, wet precipitation was primarily a solution of dilute sulphuric acid, whereas calcium and bicarbonate were the major ions in springs and ground water in two small watersheds with a deciduous forest cover in central Maryland. Dominant ions in soil water were calcium, magnesium, and sulphate. The relative importance of mineral weathering reactions on the chemical composition of these subsurface waters was compared to the contribution from wet precipitation, biological processes, and road deicing salts. Mineral reaction models, developed from geochemical mass-balance relationships, involved reactions of primary and secondary minerals in metabasalt and metarhyolite with hydrogen ion. Geochemical weathering reactions account for the majority of total ion equivalents in soil water (46 per cent), springs (51 per cent), and ground water (68 to 77 per cent). The net contribution of total ion equivalents from biological processes was 20 and 16 per cent for soil water and springs, respectively, but less than 10 per cent for ground water. The contribution of total ion equivalents from deicing salts (10 to 20 per cent) was related to proximity to roads. Strong acids in precipitation contributed 44 per cent of the total amount of hydrogen ions involved in mineral-weathering reactions for ground water in contact with metarhyolite compared to 25 per cent for ground water in contact with metabasalt, a less resistant rock type to weathering. 相似文献