首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12373篇
  免费   416篇
  2020年   173篇
  2019年   243篇
  2018年   538篇
  2017年   523篇
  2016年   602篇
  2015年   263篇
  2014年   244篇
  2013年   2861篇
  2012年   312篇
  2011年   474篇
  2010年   450篇
  2009年   317篇
  2008年   328篇
  2007年   356篇
  2006年   226篇
  2005年   190篇
  2004年   168篇
  2003年   153篇
  2002年   162篇
  2001年   168篇
  2000年   171篇
  1999年   205篇
  1998年   143篇
  1997年   104篇
  1996年   113篇
  1995年   118篇
  1994年   109篇
  1993年   110篇
  1992年   114篇
  1991年   88篇
  1990年   91篇
  1989年   98篇
  1988年   95篇
  1987年   107篇
  1986年   102篇
  1985年   138篇
  1984年   143篇
  1983年   150篇
  1982年   123篇
  1981年   117篇
  1980年   128篇
  1979年   119篇
  1978年   116篇
  1977年   121篇
  1976年   102篇
  1975年   113篇
  1974年   93篇
  1973年   90篇
  1972年   69篇
  1971年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Knee osteoarthritis (OA) is a condition that leads to functional deficits in the afflicted. Quantifying these deficits in a clinical population and relating them to bone changes in the distal femur is crucial to identifying potential impairment in archaeological populations. This study provides a hybrid knee OA grading system linking MRI observations of clinical populations and direct bone observations on skeletal populations. This system is then related to 28 pain, disability, and activity limitation outcome variables provided by the OA Initiative through frequency distributions, probability profiles, and Spearman's rank correlations. The results suggest that while the five outcome variables with the highest probabilities were common to males and females, bone changes in knee OA impact males and females differently. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
992.
The cemetery of Le Morne in Mauritius dates from the 1830s and is thought to contain the remains of slaves, freed slaves or potentially free Madagascans, which in itself has economic and social implications and makes the cemetery all the more intriguing. During 2010, excavations recovered the remains of 11 individuals, of which six were children. Although a small sample, the burials of the non‐adults show several interesting features. Two neonates were buried contemporaneously and may have been twins, while a late term foetus in a grave with a young woman may represent an incident of coffin birth. This sample has the potential to cast light on the burial practices of the slave/ex‐slave community in Mauritius, about which little is currently known. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
993.
The purpose of this research was to explore the relationship between degenerative joint disease (DJD) in the apophyseal joints and intervertebral joints in the vertebral column and assess which vertebral DJD is the more reliable indicator of general activity‐related stress. We hypothesized that the more reflecting vertebral DJD for general activity‐related stress would appear to show a higher correlation with Schmorl's nodes (SNs). To test this hypothesis, we examined 125 individuals from Eunpyeong Cemetery (mid‐15th to early 20th centuries) in Seoul, Korea and analyzed the frequencies of two types of vertebral DJD and their relationship with SNs. Cross‐tabulation chi‐square tests were used to evaluate the significance of the differences between frequencies of vertebral pathologies. In conclusion, results revealed that the relationship between the two kinds of vertebral DJD appeared differently depending on vertebral region, joint type and sex. The test results of association between the two types of vertebral DJD were statistically significant at the cervical and lumbar regions of males. SNs appeared independently of the pattern of vertebral DJD in nearly all joints with the exception of a correlation between DJD in the intervertebral joints and SNs of the lumbar region in females. As indicated in some studies, this study reconfirmed that the differences in the two kinds of vertebral DJD result from differences in normal vertebral morphology and anatomical function. This study contributes to the overall discussion on the relationship between vertebral DJD and physical activity by showing that the detailed recording and understanding of the two types of vertebral DJD is required before they can be used convincingly in a study on activity‐related stress. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
994.
Dental modification was widely practiced in sub‐Saharan Africa as a form of cultural expression, and during the era of the transatlantic slave trade, it was regularly identified in enslaved Africans who were transported to the Americas. Here, we report three new cases of African types of dental modification from the Caribbean island of Saint Martin that were recently encountered during construction activities in the Zoutsteeg area of Philipsburg, the capital of the Dutch half of the island. The artifacts associated with the burials indicate that they date to the late 17th century, prior to the foundation of the town of Philipsburg in 1735. The dental evidence further suggests that the three individuals were born in Africa, as opposed to the Americas. This could be confirmed by tooth enamel strontium isotope measurements which yielded values that are inconsistent with an origin in the Caribbean but consistent with an origin in Africa. Unfortunately, neither the dental patterns nor the strontium isotope values allow us to determine their specific origins in Africa. However, both the methods used to modify the teeth and the isotope ratios suggest that the ‘Zoutsteeg Three’ originated in different parts of Africa. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
995.
996.
997.
Mute Speech     
  相似文献   
998.
999.
1000.
Capacity design aims to ensure controlled ductile response of structures when subjected to earthquakes. This article investigates the performance of existing capacity design equations for reinforced concrete coupled walls and then proposes a new simplified capacity design method based on state-of-the-art knowledge. The new method is verified through a case study in which a set of 15 coupled walls are subject to nonlinear time-history analyses. The article includes examination of the maximum shear force in individual walls in relation to the total maximum shear force in the coupled wall system, and subsequently provides recommendations for design.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号