全文获取类型
收费全文 | 1360622篇 |
免费 | 101543篇 |
国内免费 | 1764篇 |
专业分类
耳鼻咽喉 | 17246篇 |
儿科学 | 43731篇 |
妇产科学 | 36976篇 |
基础医学 | 204514篇 |
口腔科学 | 37437篇 |
临床医学 | 126143篇 |
内科学 | 266547篇 |
皮肤病学 | 28747篇 |
神经病学 | 111365篇 |
特种医学 | 50718篇 |
外国民族医学 | 273篇 |
外科学 | 190914篇 |
综合类 | 26167篇 |
现状与发展 | 4篇 |
一般理论 | 657篇 |
预防医学 | 116000篇 |
眼科学 | 29637篇 |
药学 | 98472篇 |
7篇 | |
中国医学 | 2214篇 |
肿瘤学 | 76160篇 |
出版年
2019年 | 11553篇 |
2018年 | 15469篇 |
2017年 | 12031篇 |
2016年 | 13131篇 |
2015年 | 15159篇 |
2014年 | 20847篇 |
2013年 | 31179篇 |
2012年 | 43225篇 |
2011年 | 45779篇 |
2010年 | 26133篇 |
2009年 | 25390篇 |
2008年 | 42891篇 |
2007年 | 45653篇 |
2006年 | 45074篇 |
2005年 | 43907篇 |
2004年 | 41680篇 |
2003年 | 39876篇 |
2002年 | 38410篇 |
2001年 | 59127篇 |
2000年 | 60132篇 |
1999年 | 50905篇 |
1998年 | 14642篇 |
1997年 | 13243篇 |
1996年 | 13689篇 |
1995年 | 12776篇 |
1994年 | 11936篇 |
1993年 | 11147篇 |
1992年 | 40182篇 |
1991年 | 39435篇 |
1990年 | 38150篇 |
1989年 | 36842篇 |
1988年 | 34133篇 |
1987年 | 33291篇 |
1986年 | 31761篇 |
1985年 | 30001篇 |
1984年 | 22840篇 |
1983年 | 19949篇 |
1982年 | 11792篇 |
1979年 | 21620篇 |
1978年 | 15799篇 |
1977年 | 13125篇 |
1976年 | 12119篇 |
1975年 | 13097篇 |
1974年 | 15925篇 |
1973年 | 15695篇 |
1972年 | 14814篇 |
1971年 | 13845篇 |
1970年 | 13015篇 |
1969年 | 12295篇 |
1968年 | 11488篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
Natalie Smith-Zuzovsky Charlotte E Exner 《The American journal of occupational therapy》2004,58(4):380-388
OBJECTIVE: The purpose of this study was to examine the effect of optimal seated positioning in individually fitted furniture versus suboptimal seated positioning in standard classroom furniture on typical 6- and 7-year-old children's object manipulation skills as measured by the In-hand Manipulation Test (IMT). METHOD: An experimental research design was used to compare IMT performance of two groups of 20 children. One group was positioned in standard, too-large classroom furniture that did not support an optimal seated position, and one group was positioned optimally in furniture fitted to each child for tabletop activities, which allowed for hip flexion to 90 degrees, and foot placement on the floor, and the table to be at flexed elbow height. RESULTS: Independent groups' t tests indicated that children who were optimally positioned performed significantly better (t = -2.77, df = 38, p < .01) than children who were tested in the too-large standard classroom furniture. The difference between groups was greater on the more difficult object manipulation items (t = -3.29, df = 38, p = .001) than on the easier items (t = -1.38, df = 38, p = .08). Age and gender may have differentially affected the results. CONCLUSION: The study's results suggest that the fit of furniture relative to the child's size may have a significant impact on a young, typical child's object manipulation skills. Complex hand skills, such as those involving in-hand manipulation with stabilization, appear to be more affected by the quality of the child's seated position than are simpler, more well-established skills. Findings suggest that test administrators should strive to test young children in the most optimal seated position possible, particularly when the test involves complex hand skills. Further study is needed to assess the impact of the fit of furniture on hand skills in children with disabilities and on children's performance of other tasks. 相似文献
993.
994.
995.
According to the guidelines, ultrasonography (US) is now established as the cross-sectional imaging technique of choice in postoperative care of colorectal carcinoma. Although conventional percutaneous US is inferior to computed tomography (CT) and magnetic resonance imaging (MRI) for detecting hepatic metastases, the application of specific contrast media has significantly increased sensitivity and specificity to 87% and 88%, respectively. The combination of US and CT/MRI achieves the highest detection rates. During follow-up of rectal carcinoma, in up to 20% of locoregional recurrences are diagnosed solely by endorectal sonography and result in repeat resection with curative intention. In noncolorectal carcinoma, US is recommended in the guidelines for following up hepatocellular carcinoma and malignant thyroid disease, but the available data are insufficient to support those recommendations. 相似文献
996.
997.
998.
999.
A. B. Soares P. R. Faria L. A. Magna M. E. P. Correa C. A. de Sousa O. P. Almeida M. L. Cintra 《Journal of oral pathology & medicine》2005,34(6):368-373
BACKGROUND: Graft-vs.-host disease (GVHD) is the major cause of morbidity and mortality in patients undergoing allogeneic Bone Marrow Transplantation (BMT). The aim of our study was to identify the most relevant histological features for diagnosis of chronic Graft-vs.-Host Disease (cGVHD) in oral mucosa and minor salivary glands of 25 patients, as well as to evaluate the immunophenotype of the inflammatory cells. METHODS: Sixteen patients that were submitted to allogeneic BMT but did not present cGVHD were selected as a control group. The sections were studied on H & E and CD68, CD45, CD4, CD8, CD20 staining. RESULTS: The most frequent histologic findings in oral mucosa at the day of diagnosis of cGVHD were: hydropic degeneration of the basal layer of the epithelium, apoptotic bodies, lymphocytic infiltration, and focal or total cleavage between the epithelial and connective tissue. In the labial salivary glands (LSG), lymphocytic infiltration, acinar loss and fibrosis were the main alterations. Cytotoxic CD8-T cells and macrophages were predominant both in the epithelium and connective tissue, as well as in minor salivary glands. CONCLUSIONS: Histological features were useful in the diagnosis of oral cGVHD. It is suggested that CD8-T cells and macrophages play important role in the pathogenesis of the disease. 相似文献
1000.
BACKGROUND: The hamster cheek-pouch carcinogenesis model is a well-known animal system that closely mimics the development of premalignant and malignant lesions in human oral cancer. Our aim was to numerically characterize the premalignant and malignant lesions and expressions of field cancerization in this model using ploidy as the end-point. METHODS: To study the DNA content and proliferation status of the cells in this model we assessed the Feulgen reaction and the immunohistochemical reaction for 5-bromo-2-deoxiuridine (BrdU) in different histological areas of serial tissue sections of the cheek pouches of animals injected with BrdU. RESULTS: Ploidy values were higher in cancerized epithelia with no unusual microscopic features (NUMF), in preneoplastic and tumor areas than in control epithelia. The aneuploidy index was higher in NUMF areas than in control and differed significantly from control in preneoplastic areas and carcinoma. CONCLUSIONS: The unexpected alteration in DNA content observed in NUMF epithelia is of great relevance as a biomarker of field cancerized areas. 相似文献