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   1515篇
  免费   145篇
  国内免费   7篇
耳鼻咽喉   21篇
儿科学   20篇
妇产科学   18篇
基础医学   109篇
口腔科学   76篇
临床医学   128篇
内科学   447篇
皮肤病学   20篇
神经病学   68篇
特种医学   41篇
外科学   170篇
综合类   13篇
一般理论   1篇
预防医学   68篇
眼科学   74篇
药学   91篇
中国医学   4篇
肿瘤学   298篇
  2024年   3篇
  2023年   27篇
  2022年   43篇
  2021年   60篇
  2020年   46篇
  2019年   71篇
  2018年   72篇
  2017年   64篇
  2016年   69篇
  2015年   76篇
  2014年   80篇
  2013年   100篇
  2012年   144篇
  2011年   125篇
  2010年   90篇
  2009年   79篇
  2008年   88篇
  2007年   83篇
  2006年   95篇
  2005年   54篇
  2004年   52篇
  2003年   52篇
  2002年   37篇
  2001年   3篇
  1999年   4篇
  1998年   3篇
  1996年   2篇
  1995年   4篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1989年   3篇
  1988年   4篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1982年   3篇
  1981年   3篇
  1980年   1篇
  1977年   1篇
  1976年   2篇
  1975年   2篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
  1929年   1篇
排序方式: 共有1667条查询结果,搜索用时 20 毫秒
101.
102.
103.
Biphenotypic acute leukaemia (BAL) is a rare type of leukaemia. Whether patients with BAL should be treated with regimens designed for acute myeloid leukaemia (AML), acute lymphocytic leukaemia (ALL) or both remain unclear. We have reviewed the clinical data for 31 BAL patients. Most patients co-expressed B-lymphoid and myeloid markers. No specific chromosomal abnormality was identified. The majority of the patients were treated with regimens devised for treating ALL. Seven patients were treated with regimens designed for AML. Complete remission (CR) rates of 78% and 57% were noted respectively. The overall survival probability at 2 years was 60%.  相似文献   
104.
Aim: To determine the frequency of anti‐cyclic citrullinated peptide antibody (anti‐CCP) in a group of patients with rheumatoid arthritis and another group with other rheumatic diseases. Patients and methods: Anti‐CCP1 and rheumatoid factor (RF) titres were determined in 320 serum samples; 136 from RA patients, 184 from control patients (165 patients with rheumatic diseases other than RA, and 21 patients with lymphoproliferative diseases). Results: The sensitivity of Anti‐CCP was 62.5% (95% CI: 53–70%) for the diagnosis of RA with a specificity of 89.1% (95% CI: 83–93%). The sensitivity of RF was 85.3% (95% CI: 79–91%). The specificity was 64.7% (95% CI: 57–71%). Conclusions: Anti‐CCP1 has not very high specificity for RA regarding other rheumatic disease. However it is still very helpful for the diagnosis of RA.  相似文献   
105.
OBJECTIVES: This prospective-randomized study investigated the effect of aortic valve design and patient-prosthesis mismatch (PPM) on coronary flow reserve (CFR) after mechanical or biological aortic valve replacement (AVR) in patients with aortic stenosis (AS). BACKGROUND: Coronary flow reserve may be an important parameter of long-term survival after AVR in patients with AS. Reduced CFR may contribute to more cardiovascular events and greater rates of mortality. METHODS: A total of 48 patients undergoing AVR underwent magnetic resonance imaging for the measurement of coronary flow preoperatively, 5 days postoperatively, and at 6-month follow-up with measurement of CFR. Patients scheduled for mechanical AVR were randomized to a tilting disc or bileaflet prosthesis (n = 12 in each group). For biological AVR, patients were scheduled to receive a stented (n = 12) or stentless (n = 12) valve. Patients also underwent echocardiography with measurement of transvalvular pressure gradients and left ventricular mass regression. RESULTS: Postoperatively, coronary flow increased significantly in all groups (p < 0.001). Only stentless valves demonstrated a normal CFR (3.4 +/- 0.3 vs. 2.3 +/- 0.1 for stented biological valves, 2.1 +/- 0.2 for tilting disc, and 2.2 +/- 0.3 for bileaflet mechanical valves). Patient-prosthesis mismatch with an indexed effective orifice area <0.85 cm2/m2 led to decreased rates of CFR in the tilting disc, stentless, and stented groups. Pressure gradients were 14 +/- 3 mm Hg for tilting disc, 12 +/- 4 mm Hg for bileaflet, 19 +/- 6 mm Hg for stented, and 10 +/- 4 mm Hg for stentless valves. CONCLUSIONS: Normalization of CFR after AVR in patients with AS was observed only for stentless valves. Coronary flow reserve might explain the excellent long-term results for stentless valves. (Impact of Patient-Prosthesis Mismatch on Coronary Flow Reserve; http://www.clinicaltrials.gov/ct/show/NCT00310947?order=1; NCT00310947).  相似文献   
106.
107.
Transsphenoidal surgery (TSS) is considered first-line treatment for Cushing's disease (CD). Options for treatment of postoperative persisting hypercortisolemia are pituitary radiotherapy (RT), repeat TSS, or bilateral adrenalectomy. From 1983 to 2001, we treated 18 pediatric patients (age, 6.4-17.8 yr) with CD. All underwent TSS, and 11 were cured (postoperative serum cortisol, <50 nM). Seven (39%) had 0900-h serum cortisol of 269-900 nM during the immediate postoperative period (2-20 d), indicating lack of cure. These patients (6 males and 1 female; mean age, 12.8 yr; range, 6.4-17.8 yr; 4 prepubertal; 3 pubertal) received external beam RT to the pituitary gland, using a 6-MV linear accelerator, with a dose of 45 Gy in 25 fractions over 35 d. Until the RT became effective, hypercortisolemia was controlled with ketoconazole (dose, 200-600 mg/d) (n = 4) and metyrapone (750 mg-3 g/d) +/- aminoglutethimide (1 g/d) or o'p'DDD (mitotane, 3 mg/d) (n = 3). All patients were cured after pituitary RT. The mean interval from RT to cure (mean serum cortisol on 5-point day curve, <150 nM) was 0.94 yr (0.25-2.86 yr). Recovery of pituitary-adrenal function (mean cortisol, 150-300 nM) occurred at mean 1.16 yr (0.40-2.86 yr) post RT. At 2 yr post RT, puberty occurred early in one male patient (age, 9.8 yr) but was normal in the others. GH secretion was assessed at 0.6-2.5 yr post RT in all patients: six had GH deficiency (peak on glucagon/insulin provocation, <1.0-17.9 mU/liter) and received human GH replacement. Follow-up of pituitary function 7.6 and 9.5 yr post RT in two patients showed normal gonadotropin secretion and recovery of GH peak to 29.7 and 19.2 mU/liter. The seven patients were followed for mean 6.9 yr (1.4-12.0 yr), with no evidence of recurrence of CD. In conclusion, pituitary RT is an effective and relatively rapid-onset treatment for pediatric CD after failure of TSS. GH deficiency occurred in 86% patients. Long-term follow-up suggests some recovery of GH secretion and preservation of other anterior pituitary function.  相似文献   
108.
Although response to intranasal steroid therapy has been reported in patients with allergic rhinitis, efficacy of some nasal steroids is noteworthy.This study was undertaken to evaluate the efficacy of a two-week course of Fluticasone (Flixonase) nasal spray vs. Beclomethasone (beconase) nasal spray in patients with symptoms of allergic rhinitis referred to our clinic. This study reviewed sixty randomized studies with symptoms of allergic rhinitis which supported common aeroallergens with skin prick test. Patients received a total daily dose of nasal spray of Fluticasone (Flixonase) 100 mcg bid (N=30) compared with patients with allergic rhinitis who received a total daily dose of Beclomethasone (Beconase) 50mcg 2 puffs bid (N=30). Patients were visited before and after therapy, and efficacy of Flixonase and Beconase was evaluated by the change in nasal symptoms including: nasal discharge, nasal obstruction, nasal itching, and sneezing. After two weeks of treatment nasal symptoms of blockage, discharge, sneezing and itching were significantly better in the group treated with Fluticasone nasal spray (65%, 82%, 67%, 79% respectively (p<0.001) but after treatment with beconase nasal spray lower benefits in the nasal symptoms includes: 50%, 71%, 51%, 57% respectively. After two weeks of treatment no deleterious changes consequent to therapy were observed in nasal symptoms. 100 mcg bid Flixonase (Fluticasone) intranasal spray is more effective than 50 mcg 2 puffs bid Beconase (Beclomethasone) intranasal spray. Like asthma, allergic rhinitis is an inflammatory disease and should be managed with anti-inflammatory medication.  相似文献   
109.
Khan T  Kamali F  Daly A  King B  Wynne HA 《Age and ageing》2003,32(2):226-227
BACKGROUND: avoidance of over anticoagulation in response to warfarin therapy would reduce risk of associated bleeding. SUBJECTS: two elderly patients with venous thromboembolism exhibited extreme anticoagulant response to warfarin. Both were noted to have variant CYP2C9 alleles, which reduce the metabolic capacity of cytochrome P450 2C9. DISCUSSION: adverse outcomes with warfarin therapy could be explained and possibly avoided by identifying patients with variant alleles for CYP2C9 before initiation of therapy.  相似文献   
110.

Introduction

The study aimed to determine the association between nutrients (micronutrients, macronutrients, and antioxidants) and the occurrence of COVID-19-related outcomes (morbidity and hospitalization) using a cohort study in Western Iran.

Methods

The basic study information was collected from February 2019 to February 2020 from the baseline phase of the Dehgolan Prospective Cohort Study (DehPCS). The primary outcomes in this study included risk of contracting COVID-19 and hospitalization due to it at a specific time. To compare these outcomes based on different nutritional groups (macronutrients or micronutrients), Kaplan–Meier chart and log rank test were used. Also, univariate and multivariate regression models were used to investigate the association between different nutritional groups and desired outcomes (risk of contracting COVID-19 and hospitalization due to it at a certain time).

Results

The results showed that people having an insufficient intake of selenium (HR: 1.180; % 95 CI: 1.032–2.490; P: 0.042), vitamin A (HR: 1.119; % 95 CI: 1.020–1.442; p: 0.033), and vitamin E (HR: 1.544; % 95 CI: 1.136–3.093; p: 0.039) were significantly more infected with COVID-19 than the ones who had a sufficient intake of these nutrients. Also, the results showed that people having an insufficient intake of selenium (HR: 2.130; % 95 CI: 1.232–3.098; p: 0.018) and vitamin A (HR: 1.200; % 95 CI: 1.000–2.090; p: 0.043) were significantly hospitalized more than the ones who had a sufficient intake of these nutrients.

Conclusion

Insufficient intake of selenium and vitamins A and E can significantly increase the incidence of COVID-19 and hospitalization due to it.  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