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   7713篇
  免费   681篇
  国内免费   22篇
耳鼻咽喉   366篇
儿科学   466篇
妇产科学   379篇
基础医学   510篇
口腔科学   505篇
临床医学   718篇
内科学   1603篇
皮肤病学   193篇
神经病学   663篇
特种医学   262篇
外科学   1608篇
综合类   62篇
一般理论   1篇
预防医学   238篇
眼科学   264篇
药学   356篇
中国医学   28篇
肿瘤学   194篇
  2024年   21篇
  2023年   208篇
  2022年   144篇
  2021年   319篇
  2020年   227篇
  2019年   268篇
  2018年   594篇
  2017年   473篇
  2016年   586篇
  2015年   438篇
  2014年   676篇
  2013年   848篇
  2012年   737篇
  2011年   767篇
  2010年   596篇
  2009年   307篇
  2008年   245篇
  2007年   200篇
  2006年   180篇
  2005年   128篇
  2004年   61篇
  2003年   71篇
  2002年   63篇
  2001年   91篇
  2000年   58篇
  1999年   43篇
  1998年   32篇
  1997年   16篇
  1996年   5篇
  1995年   3篇
  1994年   4篇
  1993年   3篇
  1989年   1篇
  1987年   2篇
  1928年   1篇
排序方式: 共有8416条查询结果,搜索用时 11 毫秒
191.
Previous studies showed oxidative stress had an important impact on osteoclastic and osteoblastic functions. Oxidative stress or low levels of antioxidants are supposed to reduce BMD and cause osteoporosis. hcy, gamma glutamyltransferase (GGT), uric acid, albumin and total bilirubin are simple laboratory parameters that are related with oxidative stress. In this study we compare the serum hcy and antioxidant levels in patients with osteoporosis, osteopenia and control subjects. A total of 2190 elderly persons (1348 patients with osteoporosis, 643 patients with osteopenia and 199 control subjects) who were referred to the outpatient clinic of the Department of Internal Medicine, Division of Geriatric Medicine at Hacettepe University Hospital for comprehensive geriatric assessment were included in this cross-sectional study. Mean age of subjects were 72.30±6.34 in osteoporosis group, 71.92±6.90 in osteopenia and 71.86±5.88 in control group (p: 0.260). Multivariate regression analysis revealed that hypertension (HT) (OR: 0.675, 95% CI: 0.534-0.854, p: 0.001), diabetes mellitus (DM) (OR: 1.669, 95% CI: 1.301-2.142, p: <0.001), age (OR: 1.025, 95% CI: 1.006-1.044, p: 0.009), male gender (OR: 0.451, 95% CI: 0.358-0.569, p<0.001), uric acid (OR: 0.893, 95% CI: 0.837-0.952, p: 0.001), hcy (OR: 1.042, 95% CI: 1.023-1.061, p<0.001), albumin (OR: 0.521, 95% CI: 0.376-0.724, p<0.001), GGT (OR: 1.010, 95% CI: 1.003-1.017, p: 0.003), creatinine (OR: 0.630, 95% CI: 0.459-0.864, p: 0.004) were independent variables predicting the occurrence of osteoporosis. This study shows there is an imbalance between natural antioxidative and oxidative markers in patients with osteoporosis. Higher serum uric acid and albumin levels are associated with a lower prevalence of osteoporosis whereas higher hcy and GGT levels are associated lower BMD and higher osteoporosis prevalence.  相似文献   
192.
The aim of this study was to investigate the effects of the application of gaseous ozone and Nd:YAG laser on glass‐fibre post bond strength. Forty‐two madibular premolar roots were cut, endodontically instrumented and irrigated with 2.5% NaOCl. Post spaces were prepared and roots were divided into three groups (n = 14). The antimicrobial pretreatment was conducted as follows: gaseous ozone, Nd:YAG laser and control (no additional disinfection methods). Scanning electron microscope analysis was made for each group (n = 2). A resin cement was used for luting the posts. For push‐out test, each root was cut horizontally (two cervical, two middle and two apical). Statistical analyses were performed with one‐way anova (α = 0.05). Fracture types were observed. There was no statistically significant difference between the groups (P > 0.05). There were statistically significant differences in cervical and apical segments of laser and control groups (P < 0.05). The disinfection of the post spaces with Nd:YAG laser and ozone had no adverse effects on bond strength of glass‐fibre post.  相似文献   
193.
Oral Diseases (2012) 18 , 802–808 Objective: The aim of conducting this study was to evaluate the effect of zoledronic acid (ZA) on the new bone formation (NBF) after the insertion of a titanium dental implant, which is very popular treatment in dentistry. Study Design: Twelve New Zealand white rabbits were used in this study. The rabbits were divided in two groups. ZA was systemically administered to the study group. Titanium implants were placed to the left and right tibias of the rabbits. Results: The data from the ZA group revealed a statistically significant increase in the bone mineral content and the bone mineral density. A non‐decalcified histomorphometric examination conducted on the study group revealed a significant increase of NBF and bone‐implant contact (BIC) at 2 and 4 weeks. Conclusion: A single dose of systemic ZA administration increases the rate of NBF and augments the quality of the bone.  相似文献   
194.
The current treatment philosophy is to prevent and detect dental disease at the earliest stage in order to avoid invasive treatment. With the current understanding of the nature of dental disease and its process, the treatment philosophy is now changing to a more conservative approach and the concept of minimal intervention is gaining popularity in modern dentistry throughout the world. It is now established that demineralized but non-cavitated enamel and dentine can be healed and traditional surgical approach of drilling and filling may no longer be necessary as this only treats the symptoms of the disease and not the cause. However, when surgical intervention is indicated, the least invasive techniques such as preventive resin restoration and minimal cavity preparation are utilized. The aim of this article is to give dental professionals an overview of the concepts of minimal intervention dentistry and recent innovations in dental technology in both the diagnosis and treatment of dental caries.  相似文献   
195.
Elucidation of the molecular mechanisms of leukemogenesis is important for a better understanding of the prognosis of acute lymphoblastic leukemia (ALL). Studies have shown that the expression of upregulated gene 4 (URG4), which promotes cell growth and survival, is increased in different types of carcinomas including hepatocellular carcinoma, gastric cancer and osteosarcoma. Similarly, higher expression of URG4 and cyclin D1 gene might promote proliferation of the blast cells by causing escape from the G1 checkpoint and entry into the S phase. This study reports the high expression level of URG4 in 2 high-risk ALL patients for the first time in the literature. In conclusion, the higher expression of URG4 in our 2 patients suggests that URG4 might be involved in leukemogenesis. Future studies with a large number of high-risk ALL patients and cell culture studies are needed to demonstrate the exact role of URG4 in leukemogenesis.  相似文献   
196.
197.
Carpal tunnel syndrome (CTS) is one of the most frequent extra-articular manifestations of rheumatoid arthritis (RA). High frequency ultrasonography (US) is a sensitive and specific method in diagnosis of CTS. This study is aimed to: firstly assess diameter frequency of CTS in RA with US and compare with a control group; secondly, investigate relationship of CTS with disease activity. One hundred consecutive RA patients (women/men: 78/22) fulfilling ACR 1987 RA criteria and 45 healthy controls (women/control: 34/11) were enrolled into study. Disease activity parameters, RA and CTS patient global assessment and health assessment questionnaire (HAQ-DI) were recorded. Both patient and control group were questioned about secondary causes of CTS, and Katz hand diagram, Boston CTS questionnaire and Phalen ve Tinel tests were applied once for each hand. Wrist joint and carpal tunnel were assessed with US grey scale and power Doppler US, then cross-sectional area of median nerve (CSA) was calculated. Patients with median nerve CSA between 10.0 and 13.0 mm(2) were evaluated with electromyography (EMG). CTS was diagnosed if CSA of median nerve >13.0 mm(2) or CTS was shown with NCS. Although there was no difference between RA patients and controls in age, sex, history of DM (+) and goitre, CTS was more frequent in RA group (respectively, 17.0% vs. 4.4%, P = 0.038). In RA group with CTS, age, history of DM, disease duration, HAQ-DI score, CTS patient global score, Boston symptom severity and functional status scores were elevated compared to without CTS [respectively, 57 (36-73) vs. 50 (24-76), P = 0.041; 35.3% vs. 6.0%, P < 0.001; 108 (12-396) months vs. 72 (6-360) months, P = 0.036; 1.93 (0.75-2.87) vs. 1.125 (0-2.75), P = 0.013; 52 (1-97) vs. 25 (0-91), P = 0.001; 2.81 (1.18-4.17) vs. 2.0 (1.0-4.01), P = 0.01; 3.37 (1.37-5.0) vs. 2.25 (1.0-5.0), P = 0.008]. No difference was found between CTS (+) and (-) RA patients in acute phase reactants, disease activity and US findings (P > 0.05). Sensitivity of Katz hand diagram was higher than Tinel and Phalen tests (respectively, 100, 60.0, 66.7%). Boston symptom and functional scores of RA patients with CTS diagnosed by EMG were increased than patients CTS (-) by EMG [respectively, 3.05 (1.90-4.27) vs. 1.55 (1.0-2.90), P = 0.002; 3.25 (1.73-3.82) vs. 1.12 (1.0-2.10), P = 0.008]. CTS frequency in RA was found higher than normal population, especially in patients with additional risk factors of CTS. There was no relationship between CTS and disease activity. CTS group had long disease duration and worse functional status. CTS could be a result of the chronic course in RA. In patient with CSA between 10 and 13 mm(2), Boston CTS questionnaire might give additional idea about CTS.  相似文献   
198.
The aim of this study was to evaluate the efficacy of steroid injection for the treatment of the carpal tunnel syndrome (CTS), with F-wave parameters and sympathetic skin response (SSR). Seventeen hands of 10 women patients were treated with local steroid injection with 2-month follow-up. All patients underwent single injection into the carpal tunnel. Response to injection was measured nerve conduction studies (NCSs), median nerve F waves, and SSR before and after treatment. To determine the normal values, 42 hands of 21 healthy women were also studied. There was a significant improvement of sensory and motor nerve conduction values when compared to baseline values (P < 0.01). At the end of follow-up period, the median sensory distal latency and the sensory latency differences between the median and the ulnar nerve were improved 35 and 65%, respectively. The maximum, mean F-wave amplitudes and chronodispersion showed a slight improvement with respect to baseline values and controls, but statistical significance was not achieved after treatment. Although no statistically significant improvements were observed in SSR parameters, slightly decreased amplitudes and increased habituation of SSR were noted at the end of the treatment. The present study shows that the local steroid injection results in improvement in NCSs values, but the F-wave parameters were not effectual in short-term outcome of CTS treatment. These findings suggest that the sensory latency differences between the median and the ulnar wrist-to-digit 4 are better parameters in the median nerve recovery after treatment than the median sensory distal latency. Furthermore, the SSR does not seem to be a sensitive method in follow-up of CTS treatment.  相似文献   
199.

Objective  

This study was intended to investigate the clinical significance and molecular epidemiology of Acinetobacter baumannii complex (ABC) isolated from cerebrospinal fluid (CSF) in neurosurgical intensive care unit (NSICU) patients, particularly comparing isolates from healthcare workers’ (HCW) hands.  相似文献   
200.
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