全文获取类型
收费全文 | 180025篇 |
免费 | 36996篇 |
国内免费 | 7392篇 |
专业分类
耳鼻咽喉 | 3121篇 |
儿科学 | 3515篇 |
妇产科学 | 3080篇 |
基础医学 | 12320篇 |
口腔科学 | 6392篇 |
临床医学 | 36901篇 |
内科学 | 36515篇 |
皮肤病学 | 3990篇 |
神经病学 | 16656篇 |
特种医学 | 6820篇 |
外国民族医学 | 53篇 |
外科学 | 25976篇 |
综合类 | 14753篇 |
现状与发展 | 60篇 |
一般理论 | 6篇 |
预防医学 | 18783篇 |
眼科学 | 4715篇 |
药学 | 10004篇 |
89篇 | |
中国医学 | 4772篇 |
肿瘤学 | 15892篇 |
出版年
2024年 | 1166篇 |
2023年 | 6380篇 |
2022年 | 4745篇 |
2021年 | 7222篇 |
2020年 | 8648篇 |
2019年 | 4882篇 |
2018年 | 9824篇 |
2017年 | 9915篇 |
2016年 | 10374篇 |
2015年 | 11832篇 |
2014年 | 15156篇 |
2013年 | 15998篇 |
2012年 | 9828篇 |
2011年 | 10169篇 |
2010年 | 11063篇 |
2009年 | 12279篇 |
2008年 | 7482篇 |
2007年 | 6531篇 |
2006年 | 7713篇 |
2005年 | 6282篇 |
2004年 | 4083篇 |
2003年 | 3717篇 |
2002年 | 3186篇 |
2001年 | 3621篇 |
2000年 | 3244篇 |
1999年 | 3799篇 |
1998年 | 3469篇 |
1997年 | 3244篇 |
1996年 | 2939篇 |
1995年 | 2615篇 |
1994年 | 1941篇 |
1993年 | 1408篇 |
1992年 | 1397篇 |
1991年 | 1178篇 |
1990年 | 987篇 |
1989年 | 913篇 |
1988年 | 826篇 |
1987年 | 690篇 |
1986年 | 605篇 |
1985年 | 473篇 |
1984年 | 342篇 |
1983年 | 377篇 |
1982年 | 284篇 |
1981年 | 241篇 |
1980年 | 141篇 |
1979年 | 118篇 |
1978年 | 137篇 |
1977年 | 131篇 |
1976年 | 100篇 |
1974年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Jiuhui Jiang Jiuxiang Lin Changrong Ji 《American journal of orthodontics and dentofacial orthopedics》2005,128(4):520-527
A patient with skeletal Class III malocclusion was treated in 2 phases during the early permanent dentition. In phase 1, maxillary protraction was combined with rapid palatal expansion; in phase 2, fixed appliances were placed. The results were good posttreatment, and, 1 year later, a favorable growth tendency could be observed. This report shows that treatment for a patient with skeletal Class III malocclusion can be started in the early permanent dentition, with very good final results. 相似文献
62.
Jessica Swoboda DDS H. Asuman Kiyak MA PhD Rigmor E. Persson DDS MSD G. Rutger Persson DDS PhD David K. Yamaguchi PhD Michael I. MacEntee LDS FRCD© PhD Christopher C.L. Wyatt BSc DMD MSc 《Special care in dentistry》2006,26(4):137-144
There is limited information regarding oral health status and other predictors of oral health‐related quality of life. An association between oral health status and perceived oral health‐related quality of life (OHQOL) might help clinicians motivate patients to prevent oral diseases and improve the outcome of some dental public health programs. This study evaluated the relationship between older persons' OHQOL and their functional dentition, caries, periodontal status, chronic diseases, and some demographic characteristics. A group of 733 low‐income elders (mean age 72.7 ISD=4.71, 55.6% women, 55.1% members of ethnic minority groups in the U.S. and Canada) enrolled in the TEETH clinical trial were interviewed and examined as part of their fifth annual visit for the trial. OHQOL was measured by the Geriatric Oral Health Assessment Index (GOHAI); oral health and occlusal status by clinical exams and the Eichner Index; and demographics via interviews. Elders who completed the four‐year assessment had an average of 21.5 teeth (SD=6.9). with 8.5 occluding pairs (SD=4.6), and 32% with occlusal contacts in all four occluding zones. Stepwise multiple regressions were conducted to predict total GOHAI and its subscores (Physical, Social, and Worry). Functional dentition was a less significant predictor than ethnicity and being foreign‐bom. These variables, together with gender, years since immigrating, number of carious roots, and periodontal status, could predict 32% of the variance in total GOHAI, 24% in Physical, 27% in Social, and 21 % in the Worry subscales. These findings suggest that functional dentition and caries influence older adults' OHQOL, but that ethnicity and immigrant status play a larger role. 相似文献
63.
Lei Wang Moyi Sun Yuegui Jiang Lianjia Yang Delin Lei Chao Lu Yinghua Zhao Pu Zhang Yaowu Yang Jianhu Li 《Journal of oral and maxillofacial surgery》2006,64(4):636-641
PURPOSE: Perineural invasion is a frequent occurrence in salivary adenoid cystic carcinoma (ACC) and may prevent complete surgical resection. Studies have indicated that nerve growth factor (NGF) and its high-affinity receptor tyrosine kinase A (TrkA) may play a role in perineural invasion in several malignancies in which perineural invasion is observed. The present study was conducted to investigate the expression of NGF and TrkA in salivary ACC and to examine the effects of NGF on adhesion, migration and invasion capacities of a salivary ACC cell line (SACC-83) in vitro. PATIENTS AND METHODS: Expression of NGF and TrkA was explored using immunohistochemistry in paraffin-embedded tissues of 32 cases of salivary ACC. The effects of NGF on in vitro adhesion, migration, and invasion capacities of the SACC-83 cell line were examined using an MTT assay and a modified Boyden chamber assay respectively. RESULTS: In ACC specimens, 31 (96.9%) and 32 (100%) tumors showed immunoreactivity for NGF and TrkA respectively. Significant correlations were found between NGF/TrkA expression levels and perineural invasion (P < .05). In cell adhesion assay, the percent adherences of SACC-83 cells co-cultured with 25 ng/ml NGF at 1.5 hours and 5, 25 ng/ml NGF at 6 hours were significantly higher than that co-cultured with 0 ng/ml NGF (P < .05). However, high concentration of NGF (500 ng/ml) resulted in a significant inhibition of invasion (P < .05). CONCLUSION: Overexpression of NGF and TrkA in human salivary ACC tissues may constitute a reason for perineural invasion in salivary ACC. 相似文献
64.
65.
66.
67.
采用SD大鼠一侧大脑中动脉阻断致局限性脑缺血模型。脑缺血后迅速断头置于液氮中,HPLC外标定量法测定各磷脂组分。观察脑缺血1、5、15、60、360min时脑细胞膜磷脂含量变化。结果显示,PI在缺血早期显著低于对照组(P<0.01~0.05);PE、PC早期仅呈下降趋势,PE在缺血60min组、PC缺血360min组显著低于对照组(P<0.01~0.05)。PS在缺血全过程中变化轻微(P>0.05)。提示磷脂降解与脑缺血存在一定关系,缺血早期首先出现脑细胞膜功能磷脂降解,膜结构磷脂则在缺血后期出现显著变化,且PE较PC优先降解。 相似文献
68.
This paper describes a complex set of patient and nursing data from 83 psychiatric wards. It explains how the data were collected and organized into a meaningful format using a quality league-table. The patient and nursing characteristics of high quality psychiatric wards ranking above the 74th percentile and the characteristics of low quality wards falling below the 26th percentile are compared and examined in detail. Startling similarities and differences in patient activity, nursing activity, and nursing quality in high and low quality wards are highlighted. Finally, some implications of the findings for nursing practice, management, and education are considered. 相似文献
69.
Dr. J. Tajti MD PhD ; Dr. K. Sas MD ; Dr. D. Szok MD ; Dr. E. Vörös MD ; Dr. L. Vécsei MD DSc 《Headache》1996,36(4):259-260
We report on a patient with clusterlike headache and multiple brain metastases of lung cancer. Initially, cluster headache was suggested clinically by characteristic symptoms without any focal central nervous system signs. However, magnetic resonance imaging demonstrated multiple brain metastases. It is possible that tumor necrosis factor may have played a role in initiating the clusterlike headache. 相似文献
70.