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71.
We have shown in previous papers that a close relationship exists between the evolution of polar coronal hole area, estimated from K-coronameter observations, and the Wolf sunspot number, with a time lag of about half a solar cycle. In this paper we study the same relationship, but with the total coronal hole area at the base of the corona as obtained from a potential field model of the coronal magnetic field, which provides a more complete series of about three solar cycles. We confirm the relationship for the two last cycles and find that the forward time shift in the coronal hole area for the best correlation with sunspot number is almost the same for cycles 21 and 22, and this shift is also the time between peaks in both series. We use this result to make an early prediction of the time and size of the sunspot maximum for solar cycle 23, and find that this should occur early in 2001 and have a magnitude of about 190, similar to that of the two previous sunspot cycles. 相似文献
72.
Conventional methods of analyzing sonic log data do not always yield accurate information on each velocity segment of a well. It is shown here that the velocity-depth parameters and the sections of approximately constant velocity may be more precisely defined by using an exponential spline to model the data. 相似文献
73.
P. Stewart 《Astrophysics and Space Science》1972,18(2):377-386
A charged particle of arbitrary initial motion and position is subjected to an intense circularly polarized electromagnetic wave. The electromagnetic radiation which results is calculated exactly and the results are expressed in terms of the power observed per unit bandwidth per unit solid angle.Several special cases are considered in order to demonstrate the range of possibilities which this type of interaction may have in astrophisics and numerical examples are given for the Crab pulsar. 相似文献
74.
75.
J. Stewart Nagle 《Earth, Moon, and Planets》1980,23(2):165-183
Three soil samples at Apollo 14 Station G could potentially be used for stratigraphic correlation. Recently dissected core 14220, and core 14230 are 4 m apart and form the east leg of a triangle with an apex 7m to the west that contains trench samples 14145, 14156 and 14149, from top to bottom. Core 14220 penetrated approximately as deeply as the trench and showed a similar lithologic succession. At the base of both sections is a basalt-rich soil, overlain by a series of units that contain distinctive clasts of light soil and pebble-sized glass fragments. Fine-grained dark soil rich in vesicular glass is at the surface in both sections. The succession of similar soil types suggests that the trench correlates with 14220; but poor sample recovery makes thickness comparisons uncertain. Core 14230 appears to closely correlate with the middle of core 14220. The second layer from the top of 14220 and the top of 14230 are fine-grained with an unusually high percentage of light-matrix breccia, and the next stratum down in both cores is coarser and rich in light annealed-matrix breccia. The principal lithologic types that do not match, successionally, from core to core, are zones rich in vesicular glass and soil breccia. Such rock types are of regolith origin and probably represent patchy and discontinuous deposits. 相似文献
76.
A collection of brachiopods by the Institute of Oceanology, Academia Sinica (Qingdao), contains eight species from seven genera.
Six of the species have been recorded previously from China seas—Lingula adamsi, L. anatina, Discinisca stella, Pelagodiscus atlanticus, Campages mariae, Terebratalia coreanica. Two species (Terebratulina hataiana andFrenulina sanguinolenta) have been described from other parts of the Pacific area. The apparent absence of any endemic species is a noteworthy feature
of Chinese in comparison with Japanese faunas. 相似文献
77.
R. T. Stewart 《Solar physics》1975,40(2):417-419
78.
79.
The nitrogen relations of Enteromorpha spp. growing on intertidal mud flats have been examined over a twelve-month period. Nitrogen assimilation rates using 15N have been used to calculate the production of the alga and were between 0·046 and 0·217 mg (g dry wt alga)?1 h?1 A considerable quantity of the alga was buried beneath the sediment over the growth season and was calculated to be equivalent to an input of up to 9·52 g N m?2 per month and 32 g N m?2 over one complete growth season. Based on carbon, this latter value represented an input of approximately 320 g C m?2 annually. Low rates of nitrogenase activity (acetylene reduction) were found to be associated with the Enteromorpha. The organisms responsible for the nitrogenase activity were probably heterotrophic bacteria but they did not contribute significant quantities of nitrogen to the alga. 相似文献
80.
Linking Inuit knowledge and meteorological station observations to understand changing wind patterns at Clyde River,Nunavut 总被引:1,自引:1,他引:0
Shari Gearheard Matthew Pocernich Ronald Stewart Joelie Sanguya Henry P. Huntington 《Climatic change》2010,100(2):267-294
Connecting indigenous and scientific observations and knowledge has received much attention in the Arctic, not least in the
area of climate change. On some levels, this connection can be established relatively easily, linking observations of similar
phenomena or of various effects stemming from the same cause. Closer examinations of specific environmental parameters, however,
can lead to far more complex and difficult attempts to make those connections. In this paper we examine observations of wind
at Clyde River, Nunavut, Canada. For Inuit, many activities are governed by environmental conditions. Wind, in particular,
is identified by Inuit as one of the most important environmental variables, playing a key role in driving sea ice, ocean,
and weather conditions that can either enable or constrain hunting, travel, or other important activities. Inuit observe wind
patterns closely, and through many means, as a result of their close connection to the land and sea. Inuit in many parts of
Nunavut are reporting changes in wind patterns in recent years. At Clyde River, a community on the eastern coast of Baffin
Island, Inuit have observed that at least three key aspects of wind have changed over the last few decades: wind variability,
wind speed, and wind direction. At the same time, wind observations are also available from an operational weather station
located at Clyde River. An analysis of this information shows little change in wind parameters since the mid-1970s. Though
the station data and Inuit observations correspond in some instances, overall, there is limited agreement. Although the differences
in the two perspectives may point to possible biases that may exist from both sources—the weather station data may not be
representative of the region, Inuit observations or explanations may be inaccurate, or the instrumental and Inuit observations
may not be of the same phenomena—they also raise interesting questions about methods for observing wind and the nature of
Arctic winds. 相似文献