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291.
论我国城市气候研究工作的进展 总被引:4,自引:0,他引:4
陈明 《南京大学学报(自然科学版)》1995,31(3):529-532
回顾了我国城市气候理论的发展和研究城市气候的意义,分析目前城市气候研究中存在的问题和已取得的进展,探讨城市气候今后的研究方向,认为从定性的研究向量化的转变,从观测事实的积累和分析逐步过渡到采数学方法剖析城市气候形成的根本机制和发展演化过程,是今后城市气候研究的重要内容。 相似文献
292.
现代化城市桥梁抗震设计若干问题 总被引:15,自引:0,他引:15
范立础 《同济大学学报(自然科学版)》1997,25(2):147-154
简要讨论了现代化城市桥梁抗震设防所涉及的几个问题:即;桥梁震害的次生灾害;2.大跨度桥梁的抗震设计问题;3.城市架桥的抗震设计问题;4.城市梁抗震设计的设想。 相似文献
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294.
城市人居理想和城市问题 总被引:3,自引:0,他引:3
提出城市人居理想的核心内容是安全、天人合一、宜人性、 平等和文化性,分析了我国现代城市一系列问题:民工潮、人口老龄化、生态环境破坏和文化冲突等,指出通向城市人居理想的途径就是处理好人与自然、人与人这两对矛盾关系。 相似文献
295.
Yonglan Li Lianbin Zheng Huanjiu Xi Keli Yu Shunhua Lu Jinyuan Tian Xue Song Jinping Bao Yuling Li Xinghua Zhang Youfeng Wen Fu Ren 《科学通报(英文版)》2014,59(35):5096-5101
The body weights of 26,954 Han Chinese adults in 67 areas (16,503 in rural areas and 10,451 in urban areas) across China were measured from 2009 to 2013. The results showed that in China, the three areas (north China, northeast China, and Jianghuai Plain) were with the greatest body weight. Northwest Hart Chinese populations were heavier. Southwestern dialect groups were at the middle level and lighter than northern Han Chinese populations, but were heavier among southern Han Chinese populations. Chinese Han who located in areas of Hangjiahu were the general level, and similar to south- western dialect groups. The mean values of body weight in Hunan Han and Fujian Han were greater than other Han groups in southern China. Gan dialect groups and Can- tonese dialect groups showed the minimum body weight value in all Chinese Han groups. Besides, the mean body weight of Hakka was heavier than Gan dialect groups and Cantonese dialect groups which were adjacent to Hakka. Body weight increases with an increase in height, bone diameter, subcutaneous fat on the limbs and trunk, chest circumference, and abdomen circumference. This study revealed that northern Han men were heavier than southern Hart men, because the former were taller and had a larger waist circumference as well as thicker subcutaneous fat on their backs. Among women, height, bone diameter of the upper limbs, chest and abdomen circumferences, and sub- cutaneous fat on the limbs and trunks of northern Hart exceeded those of rural southern Han. Consequently, body weight values of northern Han women were higher than those of southern Han women. While a significant differ- ence in these values was found between urban and rural men, no significant difference occurred between urban and rural women. Body weight was associated with age in urban and rural men only in the case of minority groups. However, there was a positive correlation between body weight and age in the majority groups of both urban and rural women. The particular composition of genes involv 相似文献
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298.
恩施城区清江水质监测及初步评价 总被引:1,自引:1,他引:0
采用多点取样方法,对恩施城区清江水质进行监测分析,测定水中的溶解氧(DO),化学耗氧量(COD),五日生化需氧量(BOD5)等数据,对水质进行了初步评价。 相似文献
299.
Pollutants in stormwater runoff in Shanghai (China): Implications for management of urban runoff pollution 总被引:13,自引:0,他引:13
Runoff samples were collected from four functional areas (traffic, residential, commercial and industrial) and four roof types (old concrete,new concrete, old clay and new clay) in central Shanghai, China, during rain events. The event mean concentrations (EMCs) of three forms of nitrogen (NH4+―N,NO3-―N,NO2-―N) and the temporal variations of total phosphorus (TP) were then measured to
evaluate the effects of runoff from different areas on water quality management. The results revealed that the TP levels varied significantly in the samples collected from different functional areas and roof types during rain events. In addition, although the NO3-―N and NO2-―N concentrations in runoff remained well below the fifth class values of the national surface water quality standards, the
NH4+―N levels were 1.36, 1.17, 1.10 and 0.85 times higher than the standard value in samples collected from commercial, traffic, industrial,and residential areas, respectively. Similarly, the concentrations of NH4+―N in samples collected from old concrete, new concrete,old clay and new clay roofs exceeded the fifth class standard by 6.66, 5.72, 4.32 and 3.32 times, respectively. And the NO3-―N levels were 1.86 and 1.53 times higher than the standard values in runoff samples collected from new and old concrete roofs, respectively. 相似文献
300.
The driving mechanism behind the formation of urban thermal environments is the result of a combination of factors.Beijing was chosen as the study area,and the technique of principal component analysis (PCA) was used.A spatial regression method was also applied for quantitative explanation of the thermal mechanism.Multiple Landsat thematic mapper images were used to quantify potential causing factors.Considering the eigenvalues of each factor and its relationship with land surface temperature,the first three principal components (PCs) are regarded as the main causative factors explaining the mechanism as independent variables.The first three PCs mainly reflect urban construction,road density and the normalized difference vegetation index (NDVI),respectively.Ordinary least squares,spatial lag and spatial error regression models were established separately for the relationships between the first three PCs and land surface temperature (LST).In the two spatial regression models,z-statistics for both the spatial lag parameter (ρ) and spatial residual parameter (λ) are significant,indicating the necessity of using spatial regression to replace the OLS regression model,as well as indicating that the spatial error regression model is superior to the spatial lag regression model.Overall,the normalized difference builtup index (NDBI) and road density are the most significant positive contributions to LST. 相似文献