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951.
952.
F. Zebender P. Zimmermann R. Märki A. Hörler H. Ambübl 《Aquatic Sciences - Research Across Boundaries》1961,23(1):296-308
Ohne Zusammenfassung 相似文献
953.
954.
Mini-sosie consists in using a vibration-rammer as seismic source and changing the striking rate by varying the engine speed, resulting in a random impulse transmission. The recording instruments are made up of two seismic traces, two constant gain amplifiers and a two-channel sosie processor which performs the decoding in real time by using the actual transmission times supplied by a captor located on top of the vibration-rammer's plate. An idea of the possible penetration is given by the recording of a velocity survey. Other results obtained in seismic reflection and refraction are given. 相似文献
955.
Bioassay of a No. 2 fuel oil dispersion with shrimp in a continuous flow system using measured waterborne oil as the indicator of oil concentrations reveals a treatment more definable than those previously described in terms of volume ratios and produces lower lethal concentrations. Shrimp 96-h LC50 was 0.8 mg/l in this study as compared to values from 1.5 to 50 mg/l reported for other methods. Mean concentrations in tests do not give significant differences in concentration with respect to day of the test or spatial distribution in the exposure tanks. 相似文献
956.
Water Resources - The forked channel is a rare and poorly known type of branching channel, the distribution of flow in which is of key importance for water transport, economic activities, and water... 相似文献
957.
Flow and transport processes in porous media occur on different spatial and temporal scales and may also be locally different. Additionally, the structure of the porous medium itself generally shows a high dependence on the spatial scale. 相似文献
958.
Bhishma Tyagi A. N. V. Satyanarayana R. K. Rajvanshi M. Mandal 《Pure and Applied Geophysics》2014,171(7):1445-1459
In the present study an attempt has been made to understand the variation of surface energy fluxes such as net radiation, sensible, latent and soil heat during different epochs of thunderstorm activity at Kharagpur. The study also focuses in delineating the difference in the surface energy budget from the days of thunderstorm activity to fair weather days in the pre-monsoon months (April and May) which is locally known as thunderstorm season. For this purpose, experimental data obtained from the Severe Thunderstorms- Observations and Regional Modeling (STORM) programme during pre-monsoon months of 2007, 2009 and 2010 at Kharagpur (22°30′N, 87°20′E), West Bengal, India are used. The present study reveals quick response, in the order of a few days, in the variations of transport of energy fluxes at soil-atmosphere interface to the upper atmosphere vis-à-vis to the occurrence of thunderstorm activity. Rise of surface sensible heat flux to the level of surface latent heat flux a day or two before the occurrence of a thunderstorm has been identified as a precursor signal for the thunderstorm occurrence over Kharagpur. Distinguishable differences are found in the partitioning of the surface energy fluxes to that of net radiation between thunderstorm and non-thunderstorm days. The present study reveals more Bowen’s ratio during thunderstorm days to that of nonthunderstorm days. These results are useful in validating mesoscale model simulations of thunderstorm activity. 相似文献
959.
Brian W. Zimmer Nancy R. Riggs Gerardo Carrasco-Núñez 《Bulletin of Volcanology》2010,72(10):1223-1240
Cerro Pinto is a Pleistocene rhyolite tuff ring-dome complex located in the eastern Trans-Mexican Volcanic Belt. The complex
is composed of four tuff rings and four domes that were emplaced in three eruptive stages marked by changes in vent location
and eruptive character. During Stage I, vent clearing produced a 1.5-km-diameter tuff ring that was then followed by emplacement
of two domes of approximately 0.2 km3 each. With no apparent hiatus in activity, Stage II began with the explosive formation of a tuff ring ~2 km in diameter adjacent
to and north of the earlier ring. Subsequent Stage II eruptions produced two smaller tuff rings within the northern tuff ring
as well as a small dome that was mostly destroyed by explosions during its growth. Stage III involved the emplacement of a
0.04 km3 dome within the southern tuff ring. Cerro Pinto’s eruptive history includes sequences that follow simple rhyolite-dome models,
in which a pyroclastic phase is followed immediately by effusive dome emplacement. Some aspects of the eruption, however,
such as the explosive reactivation of the system and explosive dome destruction, are more complex. These events are commonly
associated with polygenetic structures, such as stratovolcanoes or calderas, in which multiple pulses of magma initiate reactivation.
A comparison of major and trace element geochemistry with nearby Pleistocene silicic centers does not show indication of any
co-genetic relationship, suggesting that Cerro Pinto was produced by a small, isolated magma chamber. The compositional variation
of the erupted material at Cerro Pinto is minimal, suggesting that there were not multiple pulses of magma responsible for
the complex behavior of the volcano and that the volcanic system was formed in a short time period. The variety of eruptive
style observed at Cerro Pinto reflects the influence of quickly exhaustible water sources on a short-lived eruption. The rising
magma encountered small amounts of groundwater that initiated eruption phases. Once a critical magma:water ratio was exceeded,
the eruptions became dry and sub-plinian to plinian. The primary characteristic of Cerro Pinto is the predominance of fall
deposits, suggesting that the level at which rising magma encountered water was deep enough to allow substantial fragmentation
after the water source was exhausted. Isolated rhyolite domes are rare and are not currently viewed as prominent volcanic
hazards, but the evolution of Cerro Pinto demonstrates that individual domes may have complex cycles, and such complexity
must be taken into account when making hazard risk assessments. 相似文献
960.
The seasonal nature of Australia’s tropical rivers means that connected groundwater aquifers are an important source of both
consumptive and non-consumptive water, particularly during the dry season. The management of these common pool groundwater
resources is one of the predominant water issues facing northern Australia. A national program of water reform stipulates
the expansion of water trading as a key instrument for water allocation. The effectiveness of new institutional arrangements
such as water markets will be determined mostly by how well they coordinate with local environmental requirements, local institutions
and local norms. This paper describes a novel application of combined field work, institutional analysis, experimental economics
and agent-based modeling to the analysis of a potential water market in the Katherine region of the Northern Territory, Australia.
The effectiveness of different versions of the policy instrument is assessed in light of local conditions. Instruments that
enable personal relationships and local institutions and norms to play a role in water management are found to be more effective
in terms of both farming income and environmental impact. 相似文献