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171.
付强  潘磊 《现代测绘》2015,(2):38-39
土地执法外业巡查过程中由于无法实时获取业务数据,会导致发现问题不及时等问题。系统以ArcGIS平台为基础,实现移动终端与服务器数据的实时传输,提高了外业巡查的效率和准确性,为执法监察的可视化与信息化做出了积极的尝试。  相似文献   
172.
Model experiments of a floating fish cage subjected to waves and current have been performed. The objective was to study the dynamic behaviour of the fish cage model in waves and current. The fish cage model was composed of a model net, a flexible floating collar of the circular plastic type and a weight system. It was found that there are many wave periods in which cancellation of the wave-induced forces on the model occur. These cancellation wave periods are within the range of dimensioning wave periods commonly used for testing of fish farm structures and hence are important to be aware of. Large deformations of the net under realistic wave and current conditions were observed, where contact between the net and other parts of the structure were identified. This may cause damages to the net due to abrasion.  相似文献   
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Computer vision(CV) methods for measurement of structural vibration are less expensive, and their application is more straightforward than methods based on sensors that measure physical quantities at particular points of a structure. However, CV methods produce significantly more measurement errors. Thus, computer vision-based structural health monitoring(CVSHM) requires appropriate methods of damage assessment that are robust with respect to highly contaminated measurement data. In this paper a...  相似文献   
175.
目的:筛选并分析影响肺结节良恶性的因素,建立预测模型、验证该模型并与梅奥模型、Brock模型对比。方法:回顾性分析2015年1月至2017年12月深圳市人民医院有病理结果的孤立性肺结节病例319例,其中229例作为建模组(A组),90例作为验证组(B组),分析A组病例性别、年龄、直径、吸烟史、毛刺、位于上叶、边界不清楚、分叶征、空泡征、血管集束征、胸膜凹陷征、含磨玻璃密度及钙化,通过单因素分析及Logistic回归分析,筛选出独立影响因子,并建立回归方程。用B组资料进行验证并将B组资料分别代入本研究模型、梅奥模型及Brock模型进行对比。结果:单因素分析示年龄、直径、毛刺、上叶、边界不清楚、分叶、空泡、血管集束征、胸膜凹陷征、是否含有磨玻璃密度在良恶性结节中的差异具有统计学意义(P<0.05),Logistic回归分析示有毛刺、有分叶、边界不清楚和含有磨玻璃密度为恶性孤立性肺结节的独立影响因素,并据此建立的回归方程ROC曲线下面积为0.894,其灵敏度为91.3%,特异度为77.3%,阳性似然比为4.02,阴性似然比为0.11,阳性预测值为80.8%,阴性预测值为89.5%;本研究模型与梅奥模型的差异有统计学意义(P=0.0049),与Brock模型差异没有统计学意义(P=0.79)。结论:有毛刺、有分叶、边界不清楚和含有磨玻璃密度为恶性孤立性肺结节的独立影响因素,据此建立的回归方程具有较高的诊断效能。本研究建立的模型诊断效能优于梅奥模型,与Brock模型诊断效能相当。   相似文献   
176.
目的:对比分析桥小脑角区听神经瘤MRI表现及病理特征相关性,提高对其影像诊断水平。方法:回顾性分析通过外科手术且病理证实的24例听神经瘤MRI表现,包括形态、截面大小、信号、弥散受限程度及增强扫描强化程度,与病理特征对照分析。结果:24例听神经瘤中囊实性病灶18例,14例与内听道关系密切,2例伴出血,14例病灶周围脑组织水肿,1例病灶实性部分呈轻度弥散受限,增强扫描实性部分强化,囊壁强化,囊内无强化,病理特点为Antoni A型和Antoni B型细胞共存;实性病灶4例,均与内听道关系密切,1例病灶内出血,2例伴周围脑组织水肿,2例轻度弥散受限,增强扫描均强化。病理特征:以丰富的Antoni A型细胞为主;2例囊性病灶,增强扫描囊壁强化,其中1例与内听道关系密切,1例伴有周围脑组织水肿,2例均无出血成分及弥散受限征象。病理特点:主要由Antoni B型细胞构成,囊壁成分为Antoni A型细胞。结论:听神经瘤MRI表现在一定程度上反映其病理特征,MRI检查对其诊断与鉴别诊断有一定帮助。   相似文献   
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178.

Agriculture practices have been widely proposed as the major cause of amphibian population decline. However, the majority of these results have been based on laboratory experiments. The present study was conducted to test the repercussion of wetland sediment provenance on amphibian larval development. Bufo bufo larvae were used in two different treatments in an outdoor experiment, the first one using sediment from one wetland surrounded by intensive agricultural practices, and the second using sediment with no record of agrochemical uses. A negative effect was observed in the agricultural treatment, from subcellular to individual level. The results showed that the sediment from agricultural practices watershed generates a reduction in survival. Furthermore, individuals that developed under this treatment showed a lower total length and a delay in the time necessary to complete metamorphosis; these features are connected with recruitment success. In the same way, biochemical analysis showed high values of lipid peroxidation in metamorphs developing in sediments from an agricultural area. Finally, the results obtained highlight the importance of considering the sediments, not only the water, as origin treatment, allowing us to understand the consequences on amphibian populations that inhabit areas affected by intensive agriculture.

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179.
The most heavily glacierized tropical range in the world – the Peruvian Cordillera Blanca-has been losing ice since the end of the Little Ice Age(LIA). In this study, the decline of the Churup glacier(9°28'18 " S; 77°25'02" W) and associated processes were documented employing multi-proxy approach including the analysis of remotely sensed images(1948-2016), the Schmidt hammer rock test and lichenometric dating. It is shown that Churup glacier has lost the vast majority of its estimated LIA extent(1.05 ± 0.1 km~2; 45.0×10~6-57.4×10~6 m~3). The rate of glacier retreat is documented to vary in space(SE, SW and NW-facing slopes) and time, with the peak between 1986 and 1995. With an area of 0.045 km~2 in 2016, it is expected that the complete deglaciation of the Churup valley is inevitable in the near future. Recently(post-LIA) exposed bedrock surfaces have shown higher R-values(54.2-66.4, AVG 63.3, STDEV 2.9) compared to pre-LIA exposed surfaces(46.1-59.3, AVG 50.1, STDEV 4.9), confirming the links to the duration of rock weathering. The Lichenometric dating is applied to recently exposed areas and elevations above 4800 m a.s.l., revealing only limited reliability and agreement with the age of deglaciation estimated from remotely-sensed images in such an environment.  相似文献   
180.
The purpose of this research was to investigate the relationship between soil biota such as microbial activity, soil fauna(e.g., earthworms and enchytraeids), and soil physical and chemical properties. The study area was located in Pieniny National Park(PNP) in the Carpathian Mountains in southern Poland. Soil samples were collected from six forest monitoring areas of PNP from two soil layers(at 0–15 cm and 15–30 cm down, respectively). The investigated soils were classified to eutric cambisols and had silt or silt loam soil texture. Upon analysis, soil aggregate stability index was connected with other physical, chemical, and biological soil properties.It was noted that the stability index of 3 mm to 5 mm soil aggregates influenced pH and dissolved organic carbon. The stability index of 2 mm to 3 mm soil aggregates was positively correlated with dissolved organic carbon, soil moisture, microbial biomass carbon, total organic carbon, total nitrogen, and enchytraeid density, and negatively correlated with bulk density, particle density, porosity, and permanent wilting point. The stability index of 1 mm to 2 mm soil aggregates was positively correlated with total nitrogen, enchytraeid and earthworm density and negatively correlated with particle density, porosity, and permanent wilting point. The study has shown what factors create a stable soil structure in the forest soils of PNP.  相似文献   
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