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971.
972.
Based on the method of composite analysis, the onset process and preceding signs of summer
monsoon over the South China Sea (SCS) is investigated. The result indicates that convection activities appear
first over the Indo-China Peninsula prior to the onset of the monsoon, then around the Philippines just at the
point of onset, implying that the convection activities around the Philippines serve as one of the reasons leading
to the SCS monsoon onset. Before the SCS monsoon onset, the equatorial westerly over the Indian Ocean
(75°E 95°E ) experiences noticeable enhancement and plays an important role on the SCS monsoon onset.
It propagates eastward rapidly and causes the establishment and strengthening of equatorial westerly in the
southern SCS, on the one hand, it results in the migration southward of the westerly on south side of the
south-China stationary front by means of shift northeastward of the westerly and convection over the Bay of
Bengal, on the other. Further study also shows that the intensification of equatorial westerly in the Indian Ocean
(75°E 95°E) and the southern SCS is closely related to the reinforcement of the Southern-Hemisphere
Mascarene high and Australian high, and cross-equatorial flow northward around Somali, at 85°E and 105°E,
respectively. 相似文献
973.
SEASONAL VARIATIONS OF CONVECTIVE ACTIVITIES OVER THE SOUTH CHINA SEA AND ITS NEIGHBORHOOD AND THEIR COMPARATIVE ANALYSES IN THE STRONG AND WEAK CONVECTION YEARS* 下载免费PDF全文
The seasonal variations of convective activities over the South China Sea(SCS) and its neighborhood.as well as the similarities and differences of convection in the different key regions during the strong and weak convection years are analyzed by using the pentad data of TBB from 1980 to 1993.The results show that in winter and summer the seasonal variations of the convective activities are synchronous over the SCS and its neighborhood,the anomalous convection amplitudes are obviously different in different regions.The significant extents of convective activities have somewhat seasonal differences in the strong and weak convection years.In the strong convection years,it is in winter,spring and autumn that the convection anomaly is more evident than that in the normal years,however,after the summer monsoon onset the convection is sustained.stable and similar to that in the normal years.In the weak convection years.the convection weakens greatly in each season.but the primary weakening occurs in spring.summer and autumn.No matter in the strong or the weak convection years.the convective activities are somewhat of difference in the Bay of Bengal.the Indochina Peninsula.the SCS and the Philippines.In addition.the convective activities are also different over the south and the north parts of the SCS.the convection variation in the strong year is similar to that in the weak year over the north part of the SCS.but over the south part there are great differences. 相似文献
974.
来自印度季风区的水汽输送与东亚上空水汽输送和中国夏季降水的关系 总被引:59,自引:3,他引:59
Zhang Renhe 《大气科学进展》2001,18(5):1005-1017
诊断分析了北半球夏季来自印度季风的水汽输送与东亚上空水汽输送的关系,发现二者之间具有反相变化的特征。印度季风水汽输送偏强(偏弱)时,东亚上空的水汽输送偏弱(偏强),长江中下游降水偏少(偏多)。印度夏季风水汽输送与西太平洋副热带高压强度有显著的相关关系,印度季风水汽输送偏强(偏弱)时,西太平洋副热带高压强度偏弱(偏强),由此导致副高西侧东亚上空向北的水汽输送减弱(增强),使得长江中下游降水偏少(偏多)。对反映热带对流活动的外逸长波辐射(OLR)的分析表明,印度洋上空的对流加热异常不仅能够显著地影响印度季风,也可能对东亚季风产生直接的影响。 相似文献
975.
亚洲季风区ITCZ对华北雨季异常的可能影响 总被引:1,自引:0,他引:1
分析了冬、春季亚洲季风区ITCZ活动对华北夏季降水的影响。用OLR资料定义了ITCZ综合指数,分析表明该指数能比较清晰、客观地综合反映出亚洲季风区深对流活动的强度和位置。用该指数分析了华北多雨年和少雨年前期热带大范围对流活动的变化特征。印度和东亚季风区的ITCZ活动在多雨和少雨年显示出明显不同。华北夏季降水与2-4月ITCZ综合指数的时滞相关性最明显。这种时滞相关可能与球面Rossby波的频散相联系,并可以为华北夏季降水的长期预报提供新的参考依据。低频振荡分析表明,多雨年南北两个半球的低频振荡强度较强,范围较大,并不断由南向北传播,这种传播很可能与副热带高压的北跳有关。而少雨年低频振荡在南半球或热带地区呈准静止状态。 相似文献
976.
夏季降水趋势分布预测新方法的研究及其预测试验 总被引:1,自引:0,他引:1
简要介绍了近几年来有关夏季降水趋势分布预测方法的一些研究成果,其中包括以统计学为基础的降水场预测模型、动力与统计相结合的区域气候模式及集成预测方法。 相似文献
977.
东亚夏季风与北太平洋SSTA关系的年代际变化特征及其机制研究 总被引:14,自引:1,他引:14
利用NCEP/NCAR提供的40年再分析资料和英国气象局提供的海温资料以及中国气象局整编的160站降水资料,分析了东亚夏季风以及我国华北夏季降水的年代际变化特征及其与北太平洋SSTA的关系,提出了东亚存季风在70年代中期发生显著变化,1976年前东亚夏季风偏强,受其影响华北地区夏季降水偏多,1976年以后,东亚转为弱夏季风阶段,华北地区进入少雨期,研究表明,1976年前北太平洋SSTA对大气作用显著,北太平洋海温异常对大圆波列会产生一种年际尺度的“刺激”作用叠加在年代际背景上,加强或减弱波列强度,造成强夏季风段结北夏季降水偏多气候态下的年际变化,1976年后,北太平洋地区海气温差小,海温对大气加热作用不明显,因此北太平洋海温异常通过大圆波列与东亚夏季风的联系也变得淡漠,对我国华北地区夏季降水的影响不再显著。 相似文献
978.
冬季赤道西太平洋环流状况与后期亚洲季风 总被引:4,自引:0,他引:4
基于月平均NCEP再分析资料(1958~1997年)以及中国336个台站月降水总量(195l~1994年),通过合成、相关以及统计显著性检验方法,研究了赤道西太平洋区域冬季环流状况与后期春夏季亚洲(东亚和南亚)季风环流变化的关系.研究结果表明,冬季赤道西太平洋环流状况对后期南亚季风和东亚季风以及我国夏季降水均有显著的滞后影响.冬季赤道西太平洋海域海平面气压偏高(低),对应反气旋(气旋)性环流异常,致使后期东亚和南亚夏季风均偏弱(强)以及我国长江流域夏季降水偏多(少),揭示了实施这种滞后影响的一般特征. 相似文献
979.
980.
Correlation between high-resolution climate records from a Nanjing stalagmite and GRIP ice core during the last glaciation 总被引:1,自引:0,他引:1
A 400-mm-long stalagmite from Tangshan Cave, Nanjing has been analyzed by a high-precision TIMS-U series dating method and
also determined for oxygen and carbon stable isotopic compositions. The results provided a high-resolution paleoclimate record
for eastern China during a time interval (from 54 000 to 19 000 aBP) of the last glaciation. The continuous record of oxygen-18
variations in the stalagmite, indicating a precipitation history of the East Asian monsoon, shows not only signals of the
Heinrich events, but also the Dansgaard-Oeschger cycles which are first found in the last glacial climate record of the East
Asian monsoon area. Although the stalagmite-based climatic signals match well with the GRIP ice core record, some differences
between the two records can be recognized: (1) The last glacial climate changes in eastern China exhibited a long-term remarkably
cooling trend, superimposed on which were four successive Bond’s cycles illustrated by the δ18O curve. This strong cooling tendency may be an effect of the strong summer monsoon event during the MIS 3 over the Tibetan
Plateau. (2) There exist some phase differences of 1000–2000 years between the cooling events in the stalagmite-based climate
signal and the GRIP ice core record. Such differences should be further verified by calibrations of multiple dating methods 相似文献