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961.
962.
Naifang BEI Xia LI Qiyuan WANG Suixin LIU Jiarui WU Jiayi LIANG Lang LIU Ruonan WANG Guohui LI 《大气科学进展》2021,38(7):1141-1152
The effects of aerosol–radiation interactions(ARI) are not only important for regional and global climate, but they can also drive particulate matter(PM) pollution. In this study, the ARI contribution to the near-surface fine PM(PM2.5)concentrations in the Guanzhong Basin(GZB) is evaluated under four unfavorable synoptic patterns, including "northlow", "transition", "southeast-trough", and "inland-high", based on WRF-Chem model simulations of a persistent heavy PM pollution episode in January 2019. Simulations show that ARI consistently decreases both solar radiation reaching down to the surface(SWDOWN) and surface temperature(TSFC), which then reduces wind speed, induces sinking motion,and influences cloud formation in the GZB. However, large differences under the four synoptic patterns still exist. The average reductions of SWDOWN and daytime TSFC in the GZB range from 15.2% and 1.04°C in the case of the"transition" pattern to 26.7% and 1.69°C in the case of the "north-low" pattern, respectively. Furthermore, ARI suppresses the development of the planetary boundary layer(PBL), with the decrease of PBL height(PBLH) varying from 18.7% in the case of the "transition" pattern to 32.0% in the case of the "north-low" pattern. The increase of daytime near-surface PM2.5 in the GZB due to ARI is 12.0%, 8.1%, 9.5%, and 9.7% under the four synoptic patterns, respectively. Ensemble analyses also reveal that when near-surface PM2.5 concentrations are low, ARI tends to lower PM2.5 concentrations with decreased PBLH, which is caused by enhanced divergence or a transition from divergence to convergence in an area. ARI contributes 15%–25% toward the near-surface PM2.5 concentrations during the severe PM pollution period under the four synoptic patterns. 相似文献
963.
为了确定四川盆地原油裂解气的有利分布区,利用镜质体反射率古温标重建了四川盆地的热演化史,分析了四川盆地下三叠统飞仙关组原油裂解的有利地温场分布范围及其演化特征。结果表明:四川盆地各构造单元自三叠纪以来的热流演化是不一致的,川东北地区热流在地质历史时期最低,川中地区热流也较低,而川西北和川西地区热流演化最高,这种差异与青藏高原隆升及峨眉山玄武岩地幔柱有关;四川盆地在二叠纪时期热流明显高于其他时期,但高热流持续时间较短,这主要受岩浆侵入的影响;四川盆地飞仙关组原油裂解气的有利地温分布区是不断变化的,侏罗纪末期其几乎遍及整个四川盆地,白垩纪末期其范围缩小,古近纪末期其收缩至川西和川中部分地区,现今范围则最小,主要分布在川西部分地区;控制原油裂解气分布区的主要因素是古地温场,尤其是地温最高时期的地温场,而与现今地温场的关系并不密切。 相似文献
964.
富烃凹陷是当今油气勘探的主战场,中国近海已发现的油气储量主要集中在14个富烃凹陷中。利用钻井、测井、地震及化验测试等资料,结合最新油气勘探成果,从温压系统、储盖组合、热流体活动及油气输导与聚集等方面分析、总结了中国近海典型已证实富烃凹陷的油气成藏特征。研究表明:中国近海富烃凹陷深层超压普遍发育,地温梯度高,复合型温压系统构成,为油气成藏提供了充足的动力;主力储层物性好,发育1~2套优质的区域性盖层,至少存在2套有利的储盖组合;发育多种类型的烃类包裹体,油气主成藏期集中,并存在快速幕式充注现象;发育高效优势输导体系、多种圈闭与油气藏类型,存在多种油气成藏模式,油气呈带状差异富集与分布。 相似文献
965.
Research on thermal shock resistance of mullite-bauxite-silicon carbide castable refractory 总被引:1,自引:0,他引:1
Nobuaki Chiyoda 《中国地球化学学报》2012,31(2):204-208
Effects of different silicon carbide contents on thermal shock resistance properties of mullite-bauxite castable refractory were analyzed respectively by taking the mullite,bauxite as main raw materials and taking calcium aluminate cement as a binding system.After 24 h curing in mould and another 24 h curing at 110℃ after demoulding,the samples were heated at 1000,1300 and 1500℃for 3 h in air,respectively.The bulk density,thermal expansion coefficient and thermal shock resistance were examined.The results showed that there was a great effect of content of SiC on bulk density,thermal expansion coefficient and thermal shock resistance of mullite-bauxite castable.Under the experimental conditions,the castable performed the best thermal shock resistance when w(SiC)=5%-10%. 相似文献
966.
采用新光压模型ECOMC和ECOM-9,分别使用5种IGU精密超快速星历进行精密定轨,以最终IGS精密星历作为真值,比较GPS卫星的定轨精度。结果表明,相较于ECOM-9光压模型,ECOMC光压模型能够提升卫星径向、切向和法向的轨道精度,其中径向提升较为明显;对比5种IGU超快速精密星历的定轨结果,ECOMC光压模型定轨精度分别能达到5 cm、3.5 cm、2.5 cm、1.5 cm和1.5 cm,优于ECOM-9。 相似文献
967.
968.
969.
Relation of the Second Type Thermal Helicity to Precipitation of Landfalling Typhoons: A Case Study of Typhoon Talim 下载免费PDF全文
This study utilized the MM5 mesoscale model to simulate the landfalling process of Typhoon Talim. The simulated typhoon track,
weather patterns, and rainfall process are consistent with the observation. Using the simulation results, the relation of
the second type thermal helicity (H
2) to rainfall caused by the landfalling typhoon Talim was analyzed. The results show that H
2 could well indicate the heavy inland rainfall but it did not perform as well as the helicity in predicting rainfall during
the beginning stage of the typhoon landfall. In particular, H
2 was highly correlated with rainfall of Talim at 1-h lead time. For 1–5-h lead time, it also had a higher correlation with
rainfall than the helicity did, and thus showing a better potential in forecasting rainfall intensification. Further analyses
have shown that when Talim was in the beginning stage of landfall, 1) the 850–200-hPa vertical wind shear around the Talim
center was quite small (about 5 m s−1); 2) the highest rainfall was to the right of the Talim track and in the area with a 300-km radius around the Talim center,
exhibiting no obvious relation to low-level temperature advection, low-level air convergence, and upper-level divergence;
3) the low-level relative vorticity reflected the rainfall change quite well, which was the main reason why helicity had a
better performance than H
2 in this period. However, after Talim moved inland further, 1) it weakened gradually and was increasingly affected by the
northern trough; 2) the vertical wind shear was enhanced as well; 3) the left side of the down vertical wind shear lay in
the Lushan and Dabieshan mountain area, which could have contributed to triggering a secondary vertical circulation, helping
to produce the heavy rainfall over there; hence, H
2 showed a better capacity to reflect the rainfall change during this stage. 相似文献
970.