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   25221篇
  免费   1874篇
  国内免费   157篇
耳鼻咽喉   226篇
儿科学   867篇
妇产科学   650篇
基础医学   3395篇
口腔科学   685篇
临床医学   2609篇
内科学   5152篇
皮肤病学   533篇
神经病学   2737篇
特种医学   544篇
外科学   2339篇
综合类   168篇
一般理论   39篇
预防医学   3222篇
眼科学   360篇
药学   1585篇
  1篇
中国医学   60篇
肿瘤学   2080篇
  2024年   21篇
  2023年   363篇
  2022年   605篇
  2021年   1291篇
  2020年   804篇
  2019年   1063篇
  2018年   1150篇
  2017年   883篇
  2016年   933篇
  2015年   1004篇
  2014年   1312篇
  2013年   1572篇
  2012年   2278篇
  2011年   2330篇
  2010年   1199篇
  2009年   1026篇
  2008年   1528篇
  2007年   1432篇
  2006年   1328篇
  2005年   1151篇
  2004年   985篇
  2003年   814篇
  2002年   691篇
  2001年   123篇
  2000年   110篇
  1999年   106篇
  1998年   118篇
  1997年   103篇
  1996年   76篇
  1995年   83篇
  1994年   52篇
  1993年   59篇
  1992年   64篇
  1991年   61篇
  1990年   41篇
  1989年   37篇
  1988年   54篇
  1987年   30篇
  1986年   27篇
  1985年   25篇
  1984年   35篇
  1983年   23篇
  1982年   28篇
  1981年   32篇
  1980年   22篇
  1979年   16篇
  1978年   18篇
  1977年   15篇
  1975年   15篇
  1974年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
The impact of primary hand osteoarthritis (HOA) on bone mass, microstructure, and biomechanics in the affected skeletal regions is largely unknown. HOA patients and healthy controls (HCs) underwent high-resolution peripheral quantitative computed tomography (HR-pQCT). We measured total, trabecular, and cortical volumetric bone mineral densities (vBMDs), microstructural attributes, and performed micro–finite element analysis for bone strength. Failure load and scaled multivariate outcome matrices from distal radius and second metacarpal (MCP2) head measurements were analyzed using multiple linear regression adjusting for age, sex, and functional status and reported as adjusted Z-score differences for total and direct effects. A total of 105 subjects were included (76 HC: 46 women, 30 men; 29 HOA: 23 women, six men). After adjustment, HOA was associated with significant changes in the multivariate outcome matrix from the MCP2 head (p < .001) (explained by an increase in cortical vBMD (Δz = 1.07, p = .02) and reduction in the trabecular vBMD (Δz = −0.07, p = .09). Distal radius analysis did not show an overall effect of HOA; however, there was a gender-study group interaction (p = .044) explained by reduced trabecular vBMD in males (Δz = −1.23, p = .02). HOA was associated with lower failure load (−514 N; 95%CI, −1018 to −9; p = 0.05) apparent in males after adjustment for functional status. HOA is associated with reduced trabecular and increased cortical vBMD in the MCP2 head and a reduction in radial trabecular vBMD and bone strength in males. Further investigations of gender-specific changes of bone architecture in HOA are warranted. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.  相似文献   
23.
24.
25.
26.
27.
Young children enter kindergarten with varying levels of readiness and abilities to learn. One factor that contributes to lower levels of school readiness is poverty. One timely, cost-effective, and feasible strategy to boost school readiness, regardless of exposure to high-quality preschool is to leverage the summer months prior to kindergarten entry and provide comprehensive, evidence-based programming immediately before the school year begins. The current study implemented a community-based summer programme targeted at improving school readiness for 25 four- and five-year-old children in a low-income community. Across the 9-week study, children participated in two types of early literacy activities and the Incredible Years social/emotional learning curriculum. Results indicate that participants demonstrated significant growth across three early literacy skills and were rated as overall stable regarding their behaviour across the summer. These results are discussed along with implications and future directions in this line of research.  相似文献   
28.
29.

Background

Radium 223 was introduced for metastatic castration-resistant prostate cancer based on the results of a randomized controlled trial showing risk reduction for death and skeletal events. Our aim was to evaluate the outcome of patients receiving radium 223 in a real-world setting.

Patients and Methods

We conducted a multicenter retrospective analysis in the Triveneto region of Italy.

Results

One hundred fifty-eight patients received radium 223 in our region. After a median follow-up of 9.5 months, 75 patients died. The median overall survival (OS) was 14.2 months, and the median progression-free survival (PFS) was 6.2 months. Seventy-one (45%) patients achieved progression as best response. Thirty-seven (23%) patients stopped the treatment early because of progression. Eastern Cooperative Oncology Group performance status was prognostic for OS (18.4 vs. 12.3 vs. 7.5 months; 0 vs. 1, P = .0062; 0 vs. 2, P = .0002), whereas previous prostatectomy or docetaxel exposure were not. A neutrophil to lymphocytes ratio ≥ 3 significantly impacted OS (18.1 vs. 9.7 months; P < .001) and slightly impacted PFS (6.6 vs. 5.6 months; P = .05). Patients with a baseline alkaline phosphatase (ALP) value ≥ 220 U/L had worse OS and PFS (24.1 vs. 10.5 months; 7.2 vs. 5.5 months; P < .001). Patients with changes in ALP value achieved better OS (P = .029) and PFS (P = .002). There was no difference according to the line of therapy (0 vs. ≥ 1; P = .490). The main grade 3/4 toxicities were anemia, asthenia, and thrombocytopenia.

Conclusion

This large real-world report confirms comparable OS and PFS data when compared with the pivotal study, as well as the predictive role of ALP and neutrophil to lymphocytes ratio. The definition of the optimal position of radium 223 in the treatment of metastatic castration-resistant prostate cancer has still to be defined.  相似文献   
30.
OBJECTIVE: The study aims to verify whether phonologic and rapid automatized naming (RAN) deficits are present and associated in Italian dyslexic children and whether they differentially affect dyslexics with and without a history of previous language delay (LD). BACKGROUND: According to the phonologic core deficit hypothesis, dyslexia may stem from impairment of the representation and manipulation of phonemes and may be closely associated with oral language deficits. However, deficits in tasks not requiring fine-grained phonologic representations, such as RAN, have also been described in dyslexic children. METHODS: Thirty-seven children were selected on the basis of a reading deficit and were assigned to 2 groups according to whether or not they had a history of early LD as determined retrospectively by parental report. A battery of reading and writing, verbal working memory, metaphonologic, RAN, and visual search tests were administered. RESULTS: RAN deficits were shared by most dyslexics (with and without a history of LD), whereas phonologic deficits were mainly associated with a previous LD. This last condition did not result in a more profound impairment of reading and writing decoding skills. CONCLUSION: In a shallow orthography such as Italian, RAN, not phonologic deficits, may represent the main cognitive marker of developmental dyslexia.  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