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981.
A new instrument has beendeveloped to measure the total decay rate of OH in ambient air. Theinstrument is based on the discharge flow technique in which OHgenerated within the instrument is reacted with ambient air pulled intothe flow tube. The OH decay is monitored by laser-induced fluorescence. Thistotal decay rate is compared to the sum of the individual decay rates ofOH with each trace species measured in the air to test for missing OHreactants. OH decay rates measured in an urban environment in thesummer of 1999 illustrates the promise of this technique. 相似文献
982.
Earthquake risk assessment for Istanbul metropolitan area 总被引:2,自引:2,他引:2
M. Erdik N. Aydinoglu Y. Fahjan K. Sesetyan M. Demircioglu B. Siyahi E. Durukal C. Ozbey Y. Biro H. Akman O. Yuzugullu 《地震工程与工程振动(英文版)》2003,2(1):1-23
The impact of earthquakes in urban centers prone to disastrous earthquakes necessitates the analysis of associated risk for
rational formulation of contingency plans and mitigation strategies. In urban centers, the seismic risk is best quantified
and portrayed through the preparation of “Earthquake Damage and Loss Scenarios.” The components of such scenarios are the
assessment of the hazard, inventories and the vulnerabilities of elements at risk. For the development of the earthquake risk
scenario in Istanbul, two independent approaches, one based on intensities and the second on spectral displacements, are utilized.
This paper will present the important features of a comprehensive study, highlight the methodology, discuss the results and
provide insights to future developments. 相似文献
983.
984.
Chemical denudation on a magnesian limestone hillslope,field evidence and implications for modelling
The pattern of relative denudation at the soil-bedrock interface over a wooded Magnesian Limestone hillslope was investigated using micro-weight loss bedrock tablets. The resulting pattern of weight loss after emplacement for one year indicated a consistent upslope increase in solutional denudation. Results from tablets emplaced for two years confirmed this. Dye tracing and gypsum sphere weight loss results showed that water movement over the slope was by vertical percolation and not by throughflow. The pattern of solutional denudation was related to changes in soil type and associated changes in soil pH. Continued slope development by solutional denudation will ultimately lead to slope decline. Comparison with a similar study suggests that a general soil chemistry based model of hillslope solutional denudation can be proposed. 相似文献
985.
ABSTRACTWhat is successful migration? At a macro-socio-political level migration by individuals may appear to be successful when it has met the objectives of governments, industries and domestic profit makers. However, delving beneath the surface can reveal contradictions and other measures of success at the individual, or micro-level. Within a broader critical historical ethnography, we interviewed 26 post-World War 2 (WW2) British migrants living in South Australia. All interviewees could be viewed as successful at the macro-level, having remained in Australia for many years and having established multi-generational Australian families. Their migration was a ‘success’ when measured against the priorities that were actively promoted by Australian governments in the post-WW2 period. At a micro-level, the migrants involved in this study reported mixed outcomes. While migration did result in self-identified aims of migration including employment, opportunities and adventure, some migrants reported high levels of distress and longing, linked to loss and dislocation from people and places in geographically distant locales. For some, these feelings extended into the present, raising questions over the ‘success’ of their migration experiences at a personal level. We argue that pro-active migration recruitment—such as that undertaken by Australian governments in the post-WW2 period—has the potential to pressure some persons into migration, creating ongoing and unresolvable tensions. Experiences of such disruptions merit further exploration to develop deeper critical understandings of migration success. 相似文献
986.
987.
Results from the measurement of microweight loss of Magnesian Limestone rock tablets placed at the soil–bedrock interface on a hillslope over 10 years (1982–1992) gave the same relative pattern of upslope increase in weight loss as did short-term measurements (1979–1981), but the absolute values were an order of magnitude lower (0·01–0·03 per cent per year long term and 0·1–0·6 per cent per year short term). Microweighed rock tablets may therefore give unreliable absolute rates and can only be used to indicate relative spatial differences rather than to give reliable data on temporal changes. 相似文献
988.
对未来发生地震可能造成的经济损失进行预测,是各个地区政府部门进行经济建设规划的一项必不可少的基础性工作。本文着重分析了影响地震灾害损失的因素,提出了定量计算地震灾害经济损失严重性的数学模式。 相似文献
989.
The ionizing star BD+60°2522 is known as the central star of Bubble Nebulae NGC 7635—wind-blown bubble created by the interaction
of the stellar wind of BD+60°2522 (O6.5 IIIef, V=8.7 mag, mass loss rate 10−5.76
M
⊙/year) with the ambient interstellar medium. From the evolutionary calculations for the star with mass loss and overshooting,
we find that the initial mass of the star is 60M
⊙, its present age is 2.5×106 years, and the present mass is 45M
⊙. 相似文献
990.