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41.
DAI Xiao-ai LIU Chao LI Nai-wen WANG Mei-lian YANG Yu-wei YANG Xing-ping ZHANG Shi-qi HE Xu-wei YANG Zheng-li LU Heng LI Jing-zhong WANG Ze-kun 《山地科学学报》2021,276(6):1630-1645
As one of the key parameters for characterizing crop canopy structure, Leaf Area Index (LAI) has great significance in monitoring the crop growth and estimating the yield. However, due to the nonlinearity and spatial heterogeneity of LAI inversion model, there exists scale error in LAI inversion result, which limits the application of LAI product from different remote sensing data. Therefore, it is necessary to conduct studies on scale effect. This study was based on the Heihe Oasis, Zhangye city, Gansu province, China and the following works were carried out: Airborne hyperspectral CASI (Compact Airborne Spectrographic Imager) image and LAI statistic models were adopted in muti-scale LAI inversion. The overall difference of muti-scale LAI inversion was analyzed in an all-round way. This was based on two aspects, 相似文献
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依据灾害系统理论,从生态环境脆弱性、气候变化影响风险性及社会经济暴露性三方面出发,构建中国大陆沿海城市自然灾害风险评估体系。采用乘法计算模型,即风险=脆弱性×危险性×暴露性,求得自然灾害综合评价指数。分析探究中国大陆53个沿海城市自然灾害风险特征,识别高风险、高脆弱性区域。 相似文献
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SAUTER Isabel KIENAST Felix BOLLIGER Janine WINTER Benjamin PAZÚR Robert 《山地科学学报》2019,61(12):2793-2809
Ecosystem services (ES) are highly impacted by human-induced land-use change. Progressive urbanization and agricultural land abandonment in Western Europe necessitate assessments of future land-change impacts on ES to ensure sustainable service management. The present study aims at evaluating future demand and supply of three key services (flood protection, nearby recreation and biodiversity) in the mountainous region of Vorarlberg, Austria. We mapped the ES for the referenced time step 2016 and two scenarios for 2050, assuming the continuation of current land-change trends and pressure on landscape development. Results for the referenced landscape in 2016 show the highest ES supply for intermediate levels, while ES supply was low in the lowlands and valley bottoms and in high-elevation areas. We found a high positive correlation of ES with the distribution of forested areas. In contrast, service demand was highest in low-elevation areas and decreased with increasing elevation. This indicates that densely settled and intensively used agricultural areas currently suffer from ES undersupply. The projected future development of land use showed an increase in both supply and demand of the selected ES. The overall service supply increased more than the respective demand due to some reforestation of open land. As forests were found to be important synergistic areas for overall service provision, we expect decreasing demand on related services. Locally, demand was found to exceed the supply of ES, especially in the densely populated Rhine valley- requiring further policy interventions. Such ES-related information may contribute to regional policy making and ensure the long-term provision of ESs for future generations. 相似文献
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WANG Jin-liang CHEN Cheng-long NI Jiu-pai XIE De-ti GUO Xi LUO Zhi-jun ZHAO Yue 《山地科学学报》2019,16(9):2048-2062
Ascertaining the relationship between \"source-sink\" landscape and non-point source(NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To reveal the relationships between \"sourcesink\" landscape and NPS pollution based on cell units of a small catchment in the Three Gorges Reservoir Region(TGRR), the runoff and nutrient yields were simulated first by rainfall events on a cell unit scale based on the Annualized AGricultural Non-Point Source Pollution Model(AnnAGNPS). Landscape structure and pattern were quantified with \"sourcesink\" landscape indicators based on cell units including landscape area indices and locationweighted landscape indices. The results showed that:the study case of small Wangjiagou catchment highlighted a good prediction capability of runoff and nutrient export by the AnnAGNPS model. Throughout the catchment, the spatial distribution trends of four location-weighted landscape indices were similar to the trends of simulated total nitrogen(TN) and total phosphorus(TP), which highlighted the importance of spatial arrangement of \"source\" and \"sink\" landscape types in a catchment when estimating pollutant loads. Results by Pearson correlation analysis indicated that the location-weighted landscape index provided a more comprehensive account of multiple factors, and can better reflect NPS-related nutrient loss than other landscape indices applied in single-factor analysis. This study provides new findings for applying the \"source-sink\" landscape indices based on cell units in small catchments to explain the effect of \"source-sink\" landscape on nutrient export based on cell unit, and helps improve the understanding of the correlation between \"source-sink\" landscape and NPS pollution. 相似文献
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钢筋混凝土构件的性能指标在性能化抗震设计中具有广泛应用。现有研究成果大多采用国外试验数据库,在国内实际工程结构的应用中面临挑战。因此,文中收集了国内公开发表的132组钢筋混凝土柱和24组钢筋混凝土梁的低周往复荷载试验数据,分析了《建筑抗震韧性评价标准》(GB/T 38591-2020)的转角性能指标与试验转角之间的相对误差。研究发现,《建筑抗震韧性评价标准》部分转角性能指标忽略了关键参数的影响,相对误差较高,各性能指标之间的安全冗余度相差较大。文中对此提出了修正的钢筋混凝土构件转角性能指标,更好地考虑了关键参数的影响,既降低了相对误差,又保证了安全冗余度的一致性,能够更合理地判断构件的损伤状态。 相似文献
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采用两级模糊综合评判方法,在对评判实例的稳定性因素的定性分析基础上,选取主要因素四类14项作为稳定性评价指标并将其定量化,按稳定,较稳定,较不稳定和不稳定四个级别进行综合评判,评判结果与斜坡的实际情况有较好的一致性。 相似文献
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2013年4月20日四川芦山MS7.0级地震发生后,在灾区应急获取了多种高分辨率航空和无人机遥感影像,并快速解译提取了灾区建筑物震害信息.采用地震烈度遥感定量评估方法,利用2008年汶川8.0级地震等震后震害遥感解译和现场调查研究确定的经验震害遥感定量评估模型,获得了芦山地震灾区126个主要居民点的地震烈度遥感评估结果,并据此圈画了地震烈度分布遥感评估图.结果显示,本次地震Ⅸ度区面积约150km2,Ⅷ度区面积约900km2.该结果在第一时间(4月21日晚)提供给了中国地震局地震现场应急指挥部.对比分析显示,地震烈度遥感快速评估结果与中国地震局4月25日公布的地震烈度图,以及与笔者在现场实地进行的建筑物震害详细调查结果基础上评定的地震烈度具有较高的一致性.表明强烈地震发生后,借助于快速获取的灾区高分辨率遥感影像,可以快速估计地震烈度分布,对地震灾区灾情估计和抗震救灾工作具有十分重要的参考意义. 相似文献
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