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   2003篇
  免费   110篇
  国内免费   18篇
耳鼻咽喉   18篇
儿科学   72篇
妇产科学   23篇
基础医学   223篇
口腔科学   80篇
临床医学   168篇
内科学   522篇
皮肤病学   45篇
神经病学   80篇
特种医学   205篇
外国民族医学   1篇
外科学   198篇
综合类   39篇
预防医学   92篇
眼科学   10篇
药学   96篇
中国医学   5篇
肿瘤学   254篇
  2023年   9篇
  2022年   16篇
  2021年   30篇
  2020年   29篇
  2019年   36篇
  2018年   45篇
  2017年   40篇
  2016年   39篇
  2015年   47篇
  2014年   66篇
  2013年   99篇
  2012年   111篇
  2011年   93篇
  2010年   97篇
  2009年   100篇
  2008年   79篇
  2007年   79篇
  2006年   63篇
  2005年   78篇
  2004年   62篇
  2003年   78篇
  2002年   58篇
  2001年   56篇
  2000年   52篇
  1999年   45篇
  1998年   64篇
  1997年   46篇
  1996年   45篇
  1995年   30篇
  1994年   39篇
  1993年   31篇
  1992年   25篇
  1991年   37篇
  1990年   20篇
  1989年   32篇
  1988年   30篇
  1987年   29篇
  1986年   18篇
  1985年   20篇
  1984年   13篇
  1983年   16篇
  1982年   16篇
  1981年   11篇
  1980年   15篇
  1979年   7篇
  1978年   6篇
  1977年   15篇
  1976年   11篇
  1975年   9篇
  1966年   8篇
排序方式: 共有2131条查询结果,搜索用时 0 毫秒
61.
Angiolipomas are benign mesenchymal tumors infrequently affecting the head and neck region, manifesting themselves as small (<4 cm), slow-growing mass that are painful or tender to palpation. Ultrasonography, fine needle aspiration biopsy, computed tomography, and magnetic resonance imaging can be used to make a diagnosis. Surgical excision is the treatment of choice in both infiltrating and noninfiltrating forms, even if liposuction can be considered in multiple forms. We describe a case of infiltrating intramasseterin angiolipoma, in which diagnosis was suspected after magnetic resonance imaging with gadolinium; then a transoral surgical excision was performed. To the best of our knowledge, only 1 other case of intramasseterin-infiltrating angiolipoma has been previously described.  相似文献   
62.
63.
64.
Our goal was to study deglutition of Parkinson??s disease (PD) patients and normal controls (NC) using surface electromyography (sEMG). The study included 15 patients with idiopathic PD and 15 age-matched normal controls. Surface electromyography was collected over the suprahyoid muscle group. Conditions were the following: swallow at once 10 and 20?ml of water and 5 and 10?ml of yogurt of firm consistency, and freely drink 100?ml of water. During swallowing, durations of sEMG were significantly longer in PD patients than in normal controls but no significant differences of amplitudes were found. Eighty percent of the PD patients and 20?% of the NC needed more than one swallow to consume 20?ml of water, while 70?% of the PD patients and none of the NC needed more than one swallow to consume 5?ml of yogurt. PD patients took significantly more time and needed significantly more swallows to drink 100?ml of water than normal controls. We conclude that sEMG might be a simple and useful tool to study and monitor deglutition in PD patients.  相似文献   
65.
ObjectivesThis randomised clinical trial assessed how biofilm development and composition is affected by time and denture material type in denture wearers with and without denture stomatitis.MethodsSpecimens of acrylic resin (control) and denture liners (silicone-based or acrylic resin based, depending on the experimental phase) were inserted into the surface intaglio of 30 denture wearers. Biofilm was formed in two phases of 21 days, and counts of viable micro-organisms in the accumulating biofilm were determined after 7, 14 and 21days of biofilm formation. Data were analysed by three-way ANOVA followed by Tukey test to assess differences among health condition (healthy or with denture stomatitis), materials and time point.ResultsNon-albicans Candida species counts were higher in diseased patients with silicone-based denture liners (p = 0.01). Denture stomatitis patients showed higher mutans streptococci counts after 7 days (p = 0.0041).ConclusionsLonger biofilm formation time periods did not result in differences on biofilm composition. The denture liners evaluated in this study accumulate greater amount of biofilm, and therefore their use should be carefully planned.Clinical significanceThe silicone-based denture liner tested should be used cautiously in patients with denture stomatitis as it showed increased non-albicans species counts, known to be difficult to treat.  相似文献   
66.
Transvenous Lead Extraction . Introduction: As the population ages, the number of elderly patients with implantable cardiac devices referred for transvenous lead extraction will dramatically increase in Western countries. The safety and effectiveness of lead extraction in elderly patients has not been well evaluated. We report the safety and effectiveness of transvenous lead extraction in octogenarians. Methods and Results: From January 2005 to January 2011, we reviewed data from consecutive patients ≥ 80 years referred to our institutions for transvenous lead extraction because of cardiac device infection or lead malfunction. Clinical characteristics, procedural features, and periprocedural major and minor complications were compared between octogenarians and younger patients. Out of 849 patients undergoing lead extraction in the participating institutions during the study period, 150 (18%) patients were octogenarians (mean age 84 years; range 80–96; 64% males). A significantly higher percentage of octogenarians presented with chronic renal failure (55% vs 26%; P < 0.001), history of malignancy (22% vs 6%; P < 0.001), and chronic obstructive pulmonary disease (46% vs 19%; P < 0.001). Complete lead extraction rates were similar in the 2 age groups (97% in octogenarians vs 96% in patients <80 years; P = 0.39). Periprocedural death occurred in 2 (1.3%) patients ≥80 years and in 5 (0.72%) patients <80 years (P = 0.45 for comparison). No differences in terms of other periprocedural major and minor complications were found between the 2 age groups. Conclusion: Despite presenting with a significantly higher rate of comorbidities, transvenous lead extraction can be performed safely and successfully in octogenarians. (J Cardiovasc Electrophysiol, Vol. 23 pp. 1103‐1108, October 2012)  相似文献   
67.
Despite current guidelines, variability exists in the workup of hypertensive children due to physician preferences. The study evaluates primary vs secondary hypertension diagnosis from investigations routinely performed in hypertensive children. This retrospective study included children 5 to 19 years with primary and secondary hypertension. The proportions of abnormal laboratory and imaging tests were compared between primary and secondary hypertension groups. Risk factors for primary vs secondary hypertension were evaluated by logistic regression and likelihood function analysis. Patients with secondary hypertension were younger (5-12 years) and had a higher proportion of abnormal creatinine, renal ultrasound, and echocardiogram findings. There was no significant difference in abnormal results of thyroid function, urine catecholamines, plasma renin, and aldosterone. Abnormal renal ultrasound findings and age were predictors of secondary hypertension by regression and likelihood function analysis. Children aged 5 to 12 years with abnormal renal ultrasound findings and high diastolic blood pressures are at higher risk for secondary hypertension that requires detailed evaluation.  相似文献   
68.
69.
Percutaneous balloon aortic valvotomy was attempted in six consecutiveadolescents and young adults, (meanage 18 ± 5 years),with severe congenital aortic valvular stenosis. Peak systolicaortic valve gradient measurement and aortography was performedbefore and immediately after valvotomy, and a 1–6 monthsfollow-up. The single-balloon technique was used in two patientsand the double-balloon technique in four patients. After balloonvalvotomy the mean peak systolic aortic valve gradient (PSG)decreased from 122 ± 53 to 43 ± 20 mmHg (P >001). The haemodynamic improvement persisted at follow-up (PSG= 47 ±31 mmHg), except in one patient who had previouslyundergone aortic surgical valvotomy. One balloon valvotomy wasunsuccessful, presumably because of the selection of an inappropriatelysmall balloon. Two patients with critical aortic stenosis (PSG>165mmHg), who exhibited a thick aortic valve on echocardiographywith a relatively small aortic root and annulus, had a dramaticreduction in PSG. However, the degree of aortic regurgitationincreased significantly in both cases. The theoretical haemodynamicadvantage of the double versus the single balloon techniqueswas confirmed in one patient. We have demonstrated that percutaneousballoon aortic valvotomy using either the single- or double-balloontechnique is feasible in young adults with severe congenitalaortic stenosis. Further studies are required both to defineappropriate patients and the selection of balloon diameter andlength.  相似文献   
70.
In 46 adult patients with coeliac disease, 41 (89%) of whom were positive for IgA and/or IgG antigliadin antibodies (AGA) when untreated, we investigated after a gluten-free diet the relationship between the persistence of AGA, the persistence of jejunal lesions, and the duration and compliance with the diet. IgG AGA were positive in 21 coeliac patients (46%) after variable periods of gluten-free diet and were associated with IgA positivity only in 4 cases (9%). Both IgA and IgG AGA positivity appeared to be more related to the lack of improvement of the jejunal lesions than to the strictness and duration of gluten withdrawal. Nine coeliacs showed no improvement of jejunal lesions after the gluten-free diet. Of these 9, 4 showed persistent IgA AGA, while the remaining 5 resulted IgAAGA-negative as before when untreated. Though intestinal biopsy remains the best means of determining the positive effect of gluten withdrawal, the persistence of IgA AGA in treated coeliacs is always predictive of the persistence of severe jejunal lesions. The persistence of IgG AGA, on the contrary, should be regarded as an immunological memory.  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