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本文用1959~1994年6、7、8月全国范围47个5°×5°经纬度网格降水资料分析了夏季降水异常空间模的月际差异,并在此基础上用西太平洋副高指数及青藏高原指数#FKB#FS分析降水异常空间模与环流的关系,为检验环流指数与降水相关场的整体信度,还对8月份降水资料进行了Monte-Carlo检验。结果表明,夏季总降水异常的空间模在每一月份中并非表现得同样清楚,江淮流域与河套及华南的反相关在8月份表现得最清楚。而青藏高原中东部南北两侧的负相关在6月及8月很清楚,7月份次之。8月份西太平洋副高北界异常对江淮流域与河套及华南地区降水异常反相关的产生有很大作用。副高稳定偏北时,河套、华南易涝,江淮易旱。反之亦然。青藏高原指数#FKB#FS与逐月降水的相关分析表明,青藏高原上高压及低涡活动对高原中东部南北两侧负相关的产生有一定作用。当高压活动偏多时,北侧易旱、南侧易涝。并且6月及8月的作用较大,7月较小。另外,8月份副高活动对这一降水异常空间模的产生也有一定影响。 相似文献
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赣西北地区修水县联测图组1:5万区调主要进展与体会 总被引:3,自引:0,他引:3
本文重点总结赣西北地区修水县联测图1∶5万区调取得的主要进展与区调方法上的创新。其中,在中元古界双桥山群浅变质岩系中所识别、填绘出的近东西向紧闭同斜倒转褶皱,叠加近南北向开阔圆滑褶皱,在中小型陆相红盆中探索出的运用数理统计与沉积学研究相结合确定冲积扇体,并用扇体与岩性段双重方法予以图面表达以及第四纪研究成果等取得的重要进展。此外,就有关提高区调质量等问题浅谈其体会。 相似文献
76.
Thierry Rolland Stéphanie Fayolle Arlette Cazaubon Stéphane Pagnetti 《Aquatic Sciences - Research Across Boundaries》1997,59(1):57-73
In a sub-alpine river, the Asse, with an unpredictable discharge regime, chlorophyll, density and taxonomic diversity of both
drifting and periphytic communities were studied from a methodical approach. The investigations based on stamping two close
cross-sections to know their spatial distributions in a heterogeneous bed substrate showed a heterogeneous pattern of colonization
mainly influenced by hydrological variables as the current velocity, the size of the substrata (gravel-pebble-boulder). For
the drifting algae, mainly composed with benthic species temporarily unhooked to the substrata, the heterogeneity of the distribution
was reduced in fast flow which induced a mixing of the whole mass of water.
For the periphyton, some results indicated that the greatest diversity and the highest chlorophyll concentration were found
on pebble substratum where the current velocity was moderate. These results have also shown that the classical methods used
to day for investigations were inadequate for most Mediterranean rivers.
It was really difficult to estimate the water quality from classical index created for use in regular large plain rivers. 相似文献
77.
By conducting a historical review of this large seismic event in the Mediterranean, it has been possible to identify both the epicentral area and the area in which its effects were principally felt. Ever since the nineteenth century, the seismological tradition has offered a variety of partial interpretations of the earthquake, depending on whether the main sources used were Arabic, Greek or Latin texts. Our systematic research has involved the analysis not only of Arab, Byzantine and Italian chronicle sources, but also and in particular of a large number of never previously used official and public authority documents, preserved in Venice in the State Archive, in the Marciana National Library and in the Library of the Museo Civico Correr. As a result, it has been possible to establish not only chronological parameters for the earthquake (they were previously uncertain) but also its overall effects (epicentral area in Crete, Imax XI MCS). Sources containing information in 41 affected localities and areas were identified. The earthquake also gave rise to a large tsunami, which scholars have seen as having certain interesting elements in common with that of 21 July 365, whose epicentre was also in Crete. As regards methodology, this research made it clear that knowledge of large historical earthquakes in the Mediterranean is dependent upon developing specialised research and going beyond the territorial limits of current national catalogues. 相似文献
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We present new 40Ar/39Ar data for sanidine and biotite derived from volcanic ash layers that are intercalated in Pliocene and late Miocene astronomically dated sequences in the Mediterranean with the aim to solve existing inconsistencies in the intercalibration between the two independent absolute dating methods. 40Ar/39Ar sanidine ages are systematically younger by 0.7-2.3% than the astronomical ages for the same ash layers. The significance of the discrepancy disappears except for the upper Ptolemais ashes, which reveal the largest difference, if an improved full error propagation method is applied to calculate the absolute error in the 40Ar/39Ar ages. The total variance is dominated by that of the activity of the decay of 40K to 40Ar (∼70%) and that the amount of radiogenic 40Arp in the primary standard GA1550 biotite (∼15%). If the 40Ar/39Ar ages are calculated relative to an astronomically dated standard, the influence of these parameters is greatly reduced, resulting in a more reliable age and in a significant reduction of the error in 40Ar/39Ar dating.Astronomically calibrated ages for Taylor Creek Rhyolite (TCR) and Fish Canyon Tuff (FCT) sanidine are 28.53±0.02 and 28.21±0.04 Ma (±1 S.E.), respectively, if we start from the more reliable results of the Cretan A1 ash layer. The most likely explanation for the large discrepancy found for the younger Ptolemais ash layers (equivalent to FCT of 28.61 Ma) is an error in the tuning of this part of the sequence. 相似文献
80.
应用近百年ENSO事件的研究成果和ENSO事件影响年的资料,统计分析近50年来ENSO事件与鲁西北夏季降水关系,为短期气候预测和汛期气象服务提供参考依据。 相似文献