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1.
水资源短缺一直制约着京津唐地区经济和社会的发展。20世纪70年代,因缺水引发的经济、社会问题逐渐凸显,促使中央和地方政府开始考虑实施跨流域调水工程。引滦工程作为北方最大的跨流域调水工程,其决策经历了曲折的过程。1958年,北京和唐山曾分别提出引滦河水的设想,唐山还实施了引滦入还和引还入陡工程。1972年,海河流域大旱促使中央做出加快实施引滦工程的决定,但由于地质情况复杂等原因,引滦工程设计方案被反复修改。1981年,天津提出了单独引滦济津路线并得到了中央的支持。引滦工程对缓解京津唐用水紧张发挥了重要作用,天津是引滦工程受益最大的地区。 相似文献
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The Chemical Composition and Production Area of Early Western Zhou Proto‐Porcelain Unearthed from Yejiashan Cemetery,Suizhou, China
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The bodies and glazes of 27 early Western Zhou proto‐porcelain samples from Yejiashan cemetery, Hubei Province, were analysed using LA‐ICP–AES, SEM, XRD, a thermal expansion instrument and other analytical methods. The results indicated that the bodies of all samples were characterized by high silicon and low aluminium, and were made with porcelain stone raw materials found in the south of China. The glazes are typical of high‐temperature calcium glazes of the CaO (MgO) – K2O (Na2O) – Al2O3 – SiO2 series, with relatively high Mn and P content, which was probably caused by the addition of plant ashes. The physical properties and phase compositions of Yejiashan proto‐porcelain show that firing processes were still in the early stages of development in ancient China. Multivariate statistical analyses indicated that Yejiashan proto‐porcelain might have come from the Deqing area, in Zhejiang Province. These results provide new archaeological evidence for research on issues related to material flow in the Western Zhou dynasty. 相似文献
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An Approach to the Diagnosis of Craniofacial Fibrous Dysplasia from the 2500‐Year‐Old Remains of a Skull from Ancient China
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K. L. Cheng H. Shao D. Zhao B. T. Sun J. Yu Z. C. Sun M. C. Li L. Guo H. Zhu Q. C. Zhang Y. H. Huang 《Archaeometry》2018,60(1):171-182
A human skull, buried about 2500 years ago in a Bronze Age cemetery at Jinggouzi, a site of an important ethnic group in ancient China, appeared to have characteristics of fibrous dysplasia. The CT images indicated a reduction in bone density and relatively homogeneous lesions. More features were revealed using CT reconstruction techniques. Lesions seen in low‐magnification images using a 3D deep‐field microscope had an irregular honeycomb‐like structure. At higher magnification, the trabeculae morphology and the gaps between the trabeculae were irregular and varied in size and shape. Paraffin‐embedded specimens stained with HE showed trabeculae with tortuous irregular arrangements varying in shape and width. The irregular trabeculae of woven bone has been described as having fibrous dysplasia. Molecular analysis of the GNAS gene indicated no mutation. This provides a non‐invasive approach for us to make more comprehensive diagnoses and to assist research into ancient human diseases. 相似文献
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台湾《诸罗县志》除在体例完备、内容翔实、语言精练和文体统一等方面有较高的成就之外,在有清一代所修的40多种台湾方志里,还具有其他特性,如可靠性、批判性和创见性。这些特性表明《诸罗县志》不只是一部优秀的志书,更是一部有个性的志书。 相似文献
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K. Su J.‐P. Latham D. Pavlidis J. Xiang F. Fang P. Mostaghimi J. R. Percival C. C. Pain M. D. Jackson 《Geofluids》2015,15(4):592-607
Accurate simulation of multiphase flow in fractured porous media remains a challenge. An important problem is the representation of the discontinuous or near discontinuous behaviour of saturation in real geological formations. In the classical continuum approach, a refined mesh is required at the interface between fracture and porous media to capture the steep gradients in saturation and saturation‐dependent transport properties. This dramatically increases the computational load when large numbers of fractures are present in the numerical model. A discontinuous finite element method is reported here to model flow in fractured porous media. The governing multiphase porous media flow equations are solved in the adaptive mesh computational fluid dynamics code IC‐FERST on unstructured meshes. The method is based on a mixed control volume – discontinuous finite element formulation. This is combined with the PN+1DG‐PNDG element pair, which has discontinuous (order N+1) representation for velocity and discontinuous (order N) representation for pressure. A number of test cases are used to evaluate the method's ability to model fracture flow. The first is used to verify the performance of the element pair on structured and unstructured meshes of different resolution. Multiphase flow is then modelled in a range of idealised and simple fracture patterns. Solutions with sharp saturation fronts and computational economy in terms of mesh size are illustrated. 相似文献
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Building on existing research concerned with social distance in multi-ethnic states, this study of college students in Gansu Province and Ningxia Hui Autonomous Region provides a picture of social attitudes, intra-group attachment, and inter-group social distance along ethnic and religious lines in Northwest China. The study measures inter-ethnic group fissures in Chinese society as measured in social distance between three ethnic groups: Han, Hui, and Tibetan. Comparative survey methods are used to examine inter- and intra-group relations by mapping dimensions of social distance among 382 university students. Our results indicate only very subtle differences that suggest a closer majority–minority relationship than the previous literature indicates, especially between the Hui and Han. The findings show some clustering and segregating patterns along ethnic lines, specifically when accounting for degrees of trust and tolerance and levels of ethnic and religious attachment. The Hui and Han in Ningxia exhibit closer inter-group relations in comparison to wider measurements of social distance between the Tibetan and Han in Gansu. Where the survey data revealed clustering among ethnic groups, the analysis shows that religious, geographical, and economic differences fail to account for the attitudinal differences between ethnic groups. 相似文献
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Cheng Lei Meng Hui Zhang Shi Qiang Fang 《International Journal of Architectural Heritage》2015,9(8):942-948
Ancient mortars played a crucial role in the construction of historical architectures due to their physical and chemical compatibility with traditional building materials such as stones and bricks. Therefore, the analysis and optimization of the ancient mortar formula are significant in the restoration and preservation of historical sites. In this work, 20 mortar samples selected from five ancient stone pagodas in Zhejiang Province, China, were analyzed. The results showed that mud, lime-soil mortar, lime-sand mortar, and lime-gypsum mortar were used as binders in these pagodas. The Ca(OH)2/aggregate ratio ranging from 0.3 to 2.7 was usually used to prepare lime mortar. Protein and polysaccharide were also found in some samples. 相似文献