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   4035篇
  免费   145篇
  国内免费   19篇
耳鼻咽喉   109篇
儿科学   231篇
妇产科学   315篇
基础医学   263篇
口腔科学   218篇
临床医学   275篇
内科学   865篇
皮肤病学   76篇
神经病学   242篇
特种医学   121篇
外科学   956篇
综合类   47篇
预防医学   65篇
眼科学   119篇
药学   175篇
中国医学   7篇
肿瘤学   115篇
  2024年   2篇
  2023年   19篇
  2022年   48篇
  2021年   106篇
  2020年   51篇
  2019年   70篇
  2018年   108篇
  2017年   77篇
  2016年   139篇
  2015年   154篇
  2014年   150篇
  2013年   193篇
  2012年   264篇
  2011年   273篇
  2010年   178篇
  2009年   150篇
  2008年   330篇
  2007年   340篇
  2006年   307篇
  2005年   320篇
  2004年   303篇
  2003年   260篇
  2002年   207篇
  2001年   29篇
  2000年   23篇
  1999年   19篇
  1998年   17篇
  1997年   15篇
  1996年   11篇
  1995年   2篇
  1994年   11篇
  1993年   6篇
  1992年   7篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
  1973年   1篇
排序方式: 共有4199条查询结果,搜索用时 15 毫秒
81.
Objectives: To explore choroidal thickness (ChT) and retinal thickness (RT) changes in patients with type 1 diabetes mellitus (DM).

Methods: Sixty patients with Type 1 DM and 60 age- and sex-matched healthy controls were included in this prospective case–control clinical study. All patients underwent a complete ophthalmological examination. ChT of each participant was measured at the fovea and horizontal nasal and temporal quadrants at 500-µm intervals to 1500 µm from the foveola using spectral-domain optical coherence tomography (SD-OCT). Age, gender, disease duration, serum glycosylated hemoglobin (HbA1c), fasting glucose level, axial length (AL) and refractive error were noted and analyzed.

Results: Mean disease duration, mean HbA1c and mean fasting blood glucose in diabetic patients were 6.1±2.8 years, (8.9±0.9)% and 287.5±69.1 mg/dl, respectively. Age, gender, AL, spherical equivalent differences between the patients and subjects were insignificant (p>0.05). Subfoveal ChT, nasal quadrant ChT measurements, temporal 1500 µm and mean nasal ChT were significantly lower in diabetic patients (p<0.05 for all). Temporal 500 µm and 1000 µm ChT measurements, mean temporal ChT, average ChT, central macular thickness and average macular thickness did not differ significantly between the groups (p>0.05 for all).

Conclusion: This study showed that there is choroidal thinning in young Type 1 diabetic patients with early period of disease duration without diabetic retinopathy nor any other systemic diseases. Choroidal changes in type 1 DM seem to begin at nasal and distal temporal retina. These results need to be verified by larger and longitudinal studies.  相似文献   

82.
83.
Background Metastasis to bone from endometrial adenocarcinoma is rare, when metastasises it usually locates in axial skeleton. Metastasis to extremities is extremely rare. Additionally the detection of the bone metastasis as a presenting feature is uncommon. In the present study we report the 10th cases of bone metastasis in the literature which located at tibial diaphysis and originated from endometrial adenocarcinoma as a presenting feature of the primary disease. Case Single tibial lesion was observed in a 70 years old woman. Biopsy confirmed metastatic adenocarcinoma of the unknown origin. We couldn’t find the primary origin with aggressive work-up. Tibial lesion regressed with radiotherapy. Endometrial adenocarcinoma is detected after the end of disease-free one year with the symptom of vaginal bleeding. After 47 months from initial tibial lesion and 35 months from gynaecologic operation, patient is still alive and disease free. Discussion Patients with endometrial adenocarcinoma presenting an isolated skeletal metastasis may exhibit an unusual group with a better prognosis. This study was presented as a poster exhibition at the 5th Meeting of Asia-Pasific Musculo Skeletal Tumour Society held between 23 and 25, April 2004, Izmir, Turkey.  相似文献   
84.
85.
Rheumatic diseases are chronic inflammatory diseases which cause mild to severe functional loss and disability due to articular and extra-articular manifestations. One common form -ankylosing spondylitis (AS)- affects mainly the axial skeleton and sacroiliac joints, and certain extra-articular organs. The pulmonary involvement is a known manifestation of AS and emerges either in the form of interstitial lung disease or in the form of restricted pulmonary functions. The aim of this study is to determine the pulmonary functions in AS patients and to assess its relationship with quality of life, functionality and disease activity. Thirty-six AS patients and 34 healthy volunteers were recruited for the study. A detailed examination, pulmonary function tests, smoking inquiry and quality of life questionnaire were performed on all participants. Also patients were requested to complete functionality and disease activity indexes. The outcomes showed that 15 (41.7%) AS patients had pulmonary involvement: twelve patients with restrictive patterns, one with obstructive pattern, and two with both restrictive and obstructive patterns. Decreased forced expiratory volume in one second was associated with deteriorated functionality (p < 0.05). Decreased chest expansion was also accompanied with decreased forced vital capacity (p < 0.05). There was no statistically significant difference between the smoking and non-smoking patients in regard to disease activity, functionality and pulmonary function test variables (p > 0.05). In conclusion, the pulmonary involvement is common in AS and might have disturbed functionality and the quality of life in AS patients.  相似文献   
86.
OBJECTIVE: To increase retention of overdentures in cleft palate patients by means of heightened telescopic copings with a newly designed attachment. In this study, a "precision attachment" is described to develop the stability and retention of telescopic overdentures. CASE: A cleft palate patient was treated with a newly designed overdenture. Intraoral examination revealed poor tooth structure and retention. Therefore, a new semiprecision attachment was designed in order to increase retention and stabilization. CONCLUSION: The patient's tolerance was increased with the new overdenture.  相似文献   
87.

Background

Many studies have indicated a relationship between diabetes and Alzheimer’s disease (AD). However, the molecular mechanism underlying this association has not been clarified. Among several factors, insulin degrading enzyme (IDE), which plays roles in the degradation of both insulin and amyloid β (Aβ), has gained interest as a potential target in efforts to solve this puzzle. This study sought to examine the effects of varying insulin and/or glucose concentrations on IDE expression.

Methods

Experiments were performed on primary cultured rat neurons and cortices of rats with streptozotocin (STZ)-induced diabetes. IDE protein and mRNA expression levels were measured by western blot and RT-PCR, respectively.

Results

In primary cultured cortical neurons, removal of insulin for 5 days reduced the expression of IDE. A five-day treatment with a high concentration of glucose in insulin-free media reduced IDE levels, while a high concentration of glucose in the presence of insulin had no effect. In groups treated with glucose or insulin intermittently, the reduction in IDE levels was observed only in neurons exposed to high glucose together with no insulin for 5 days. Shorter incubation periods (48 h), either continuously or intermittently, did not affect IDE levels. IDE expression in the cortex of rats with STZ-induced diabetes was found to be decreased.

Conclusion

Our data suggest that insulin deprivation, rather than high glucose, is a significant determinant of IDE regulation. As evidence indicates potential roles for IDE in diabetes and AD, understanding the mechanisms regulating IDE expression may be important in developing new treatment strategies.  相似文献   
88.
Endothelial IKCa and/or SKCa channels play an important role in the control of vascular tone by participating in endothelium‐dependent relaxation. Whether β‐AR antagonists, mainly used in hypertension, affect endothelial KCa channel function is unknown. In this study, we examined the effect of the β2‐AR antagonist and inverse agonist ICI 118,551 on the IKCa/SKCa channel activity by assessing functional relaxation responses to several agonists that stimulate these channels. Mesenteric arterial rings isolated from male Sprague Dawley mounted to organ baths. Acetylcholine elicited IKCa‐ and SKCa‐mediated relaxations that were abolished by TRAM‐34 and apamin, respectively. ICI 118,551, which did not dilate the arteries per se, increased the IKCa‐mediated relaxations, whereas SKCa‐mediated relaxations remained unaltered. Same potentiating effect was also detected on the IKCa‐mediated relaxations to carbachol and A23187, but not to NS309. Neither acetylcholine‐induced nitric oxide‐mediated relaxations nor SNP relaxations changed with ICI 118,551. The PKA inhibitor KT‐5720, the selective β2‐AR agonist salbutamol, the selective β2‐AR antagonist butoxamine, the non‐selective β‐AR antagonist propranolol, and the inverse agonists carvedilol or nadolol failed to affect the IKCa‐mediated relaxations. ICI 118,551‐induced increase was not reversed by salbutamol or propranolol as well. Besides, low potassium‐induced relaxations in endothelium‐removed arteries remained the same in the presence of ICI 118,551. These data demonstrate a previously unrecognized action of ICI 118,551, the ability to potentiate endothelial IKCa channel‐mediated vasodilation, through a mechanism independent of β2‐AR antagonistic or inverse agonistic action. Instead, the enhancement of acetylcholine relaxation seems likely to occur by a mechanism secondary to endothelial calcium increase.  相似文献   
89.
We aimed to correlate the predisposing demographic and clinical factors for erectile dysfunction (ED) in young men and treatment response in these men with data from older men. The patients were divided into two groups: <40 years (group I, n = 58) and ≥40 years (group II, n = 73). ED was evaluated with the International Index of Erectile Function-5 (IIEF-5) questionnaire, and Beck's Depression Inventory (BDI) questionnaire was used to evaluate mood status. The number of patients with morning rigidity and normal libido was higher in group I (70.7% vs. 16.4%, p = .039 and 72% vs. 37%, p = .047). The increase in scores other than IIEF-Orgasmic Function and Sexual Desire domain scores after treatment was higher in the first group (p = .029, p = .035 and p < .001 respectively). In multivariate analysis, the factors predicting the low IIEF-Erectile Function domain score in young men were testosterone level and BDI score (p = .026 and p = .034). Although psychogenic factors contribute significantly to the aetiology of ED, hormone profile is more preserved in young men than in older men.  相似文献   
90.

Purpose

This study investigated the efficacy of platelet-rich plasma (PRP) on articular surfaces on which the mosaicplasty technique was performed. Our hypothesis was that PRP can accelerate the osseointegration process and enhance the quality of articular integrity after the mosaicplasty procedure.

Methods

Standard defects were created in the femoral groove of both patellofemoral joints of 12 New Zealand rabbits. PRP solution was placed inside the defect before fixation of the osteochondral autografts and injected inside the involved joint after capsular closure of the tested knees. The contralateral knees served as the control sides. The animals were euthanized three or six weeks after mosaicplasty, and both limbs were assessed according to Pineda’s histological grading scale. Significance level was set at p ≤ 0.05 a priori, and the Mann–Whitney U test was used for statistical analysis.

Results

Histologic findings at the interface between the transferred autograft and the original cartilage revealed better integration of the adjacent surfaces in the mosaicplasty with PRP group three weeks after the procedure; the difference was significant (p < 0.05). However, no significant difference in the transition zone was observed between the groups six weeks after the experiment (p = 0.59).

Conclusions

Our animal model showed that adjunctive use of PRP produced a better healing response and resulted in superior histological scores after three weeks compared with the mosaicplasty-only procedure. Interpretation of our results is important in terms of rapid return to previous activity levels. Thus, application of PRP can represent a valid therapeutic option for improving the efficacy of mosaicplasty by stimulating the local healing response.  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