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   2088篇
  免费   117篇
  国内免费   8篇
耳鼻咽喉   42篇
儿科学   129篇
妇产科学   179篇
基础医学   185篇
口腔科学   153篇
临床医学   180篇
内科学   336篇
皮肤病学   66篇
神经病学   139篇
特种医学   73篇
外科学   330篇
综合类   37篇
预防医学   67篇
眼科学   53篇
药学   87篇
中国医学   56篇
肿瘤学   101篇
  2024年   3篇
  2023年   34篇
  2022年   45篇
  2021年   77篇
  2020年   45篇
  2019年   69篇
  2018年   79篇
  2017年   68篇
  2016年   104篇
  2015年   101篇
  2014年   116篇
  2013年   132篇
  2012年   159篇
  2011年   189篇
  2010年   93篇
  2009年   106篇
  2008年   162篇
  2007年   133篇
  2006年   127篇
  2005年   132篇
  2004年   85篇
  2003年   78篇
  2002年   41篇
  2001年   5篇
  2000年   4篇
  1999年   6篇
  1998年   2篇
  1997年   2篇
  1996年   3篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1989年   1篇
  1979年   2篇
  1966年   1篇
  1965年   1篇
排序方式: 共有2213条查询结果,搜索用时 15 毫秒
11.
IntroductionEosinophilic airway inflammation is a recognized inflammatory pattern in subgroups of patients with chronic obstructive pulmonary disease (COPD). However, there are still conflicting results between various studies concerning the effect of eosinophils in COPD patients. Our aim with this study was to evaluate eosinophilic inflammation and its relation to the clinical characteristics in a group of COPD patients.MethodsStable COPD patients with FEV1% predicted < 50 or with ≥ 1 exacerbation leading to hospital admission or ≥2 moderate or severe exacerbation history were consecutively enrolled from outpatient clinics.ResultsWe included 90 male COPD patients, with a mean age of 63.3 ± 9.2. Mean FEV1% predicted was 35.9 ± 11.3. Eosinophilic inflammation (eosinophil percentage ≥2%) was evident in 54 (60%) of the patients. Participants with eosinophilic inflammation were significantly older and had better FEV1 predicted % values. Eosinophilic COPD patients were characterized with better quality of life and fewer symptoms. COPD patients with noneosinophilic inflammation used supplemental long‐term oxygen therapy (LTOT) more frequently compared to patients with eosinophilic inflammation (36.1% vs. 14.8%, p = 0.01). Eosinophilic inflammation is associated with less dyspnea severity measured by mMRC (OR: 0.542 95% CI: 0.342–0.859, p = 0.009) and less LTOT use (OR: 0.334 95% CI: 0.115–0.968, p = 0.04) regardless of age, severity of airflow limitation, and having frequent exacerbation phenotype.ConclusionOur study supports the growing evidence for a potential role of eosinophilic inflammation phenotype in COPD with distinctive clinical characteristics. Eosinophilic inflammation is inversely associated with dyspnea severity measured by mMRC and LTOT use independently from age, total number of exacerbations, St. George Respiratory Questionnaire (SGRQ) total score and FEV1% predicted.  相似文献   
12.
We report an unusual case of psoas abscess,which developed twenty-one years afteripsilateral nephrectomy and was caused byinfrequent pathogen, Proteus mirabilis.It was diagnosed by computed tomography andwas drained percutaneously with a nephrostomytube guided by ultrasonography.  相似文献   
13.
Cyclophosphamide (CYC) has been the landmark in the treatment of lupus nephritis. However, long-term treatment with CYC is associated with significant side effects. We aimed to evaluate the efficacy of short-term intravenous (IV) CYC treatment as a remission induction treatment followed by azathioprine (AZA) or mycophenolate mofetil (MMF) as a maintenance treatment. Twenty patients (18 girls) with biopsy-proven class III (5) and IV (15) lupus nephritis were included in to the study. Detailed clinical and laboratory data and patient outcomes were evaluated. All patients received three methylprednisolone (MP) IV pulses, followed by oral prednisone 0.5−1 mg/kg per day and one IV pulse of CYC per month for 6 months. Azathioprine was started as a remission-maintaining treatment. In ten of 20 patients, treatment was switched to MMF. The mean age at the time of diagnosis was 16.11 ± 3.49 years, and the mean duration of follow-up was 49.6 ± 27 months. Fourteen patients (70%) had complete remission, three (15%) had partial remission, one (5%) continued to have active disease, and two (10%) progressed to end-stage renal disease. Nine of the patients (45%) with complete remission had received AZA, and switching to MMF increased complete remission rate (additional five patients; 25%). In conclusion, short-term (6-month) IV bolus CYC treatment followed by AZA is a safe and effective treatment in children with severe lupus nephritis, and using MMF increases remission rate in resistant cases.  相似文献   
14.

Background:

Oxidative stress is a mediator of secondary injury to the spinal cord following trauma.

Objective:

To investigate the putative neuroprotective effect of α-lipoic acid (LA), a powerful antioxidant, in a rat model of spinal cord injury (SCI).

Methods:

Wistar albino rats were divided as control, vehicle-treated SCI, and LA-treated SCI groups. To induce SCI, a standard weight-drop method that induced a moderately severe injury (100 g/cm force) at T10 was used. Injured animals were given either 50 mg/kg LA or saline at 30 minutes postinjury by intraperitoneal injection. At 7 days postinjury, neurologic examination was performed, and rats were decapitated. Spinal cord samples were taken for histologic examination or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity, and DNA fragmentation. Formation of reactive oxygen species in spinal cord tissue samples was monitored by using a chemiluminescence (CL) technique.

Results:

SCI caused a significant decrease in spinal cord GSH content, which was accompanied with significant increases in luminol CL and MDA levels, MPO activity, and DNA damage. Furthermore, LA treatment reversed all these biochemical parameters as well as SCI-induced histopathologic alterations. Conversely, impairment of the neurologic function caused by SCI remained unchanged.

Conclusion:

The present study suggests that LA reduces SCI-induced oxidative stress and exerts neuroprotection by inhibiting lipid peroxidation, glutathione depletion, and DNA fragmentation.  相似文献   
15.
The matrix metalloproteinase-9 (MMP-9) and neutrophil gelatinase associated lipocalin (NGAL) are shown to increase in an inflammatory situation. Based on our previous reports that NGAL can be detected in the urine of children with urinary tract infection (UTI), we also asked whether MMP-9/NGAL complex could be detected in the urine of children with UTI. This multicenter, prospective study was conducted between October 2009 and October 2010. Seventy-one patients with symptomatic culture proven UTI, 37 asymptomatic children with contaminated urine and 37 healthy children were recruited. Mean uMMP-9/NGAL/Cr levels were significantly higher in the UTI group than in the control group (p < 0.0001). According to ROC analysis, the optimal cut-off level was 0.08 ng/mg to predict UTI. Using a cut-off value, sensitivity and specificity were 98.6 and 97.3%, respectively. The mean levels of uMMP-9/NGAL/cr in the UTI group were also significantly higher than those in the contamination group (p < 0.0001). There was no statistically significant difference between contamination group and the control group (p = 0.21). The mean uMMP-9/NGAL/Cr in the UTI group were significantly higher before treatment than after treatment (p < 0.0001). The area under the curve was 0.997 (SE: 0.002, 95% CI: 0.993 to 1.001) for uMMP-9/NGAL/Cr. Urinary MMP-9/NGAL/Cr level was also correlated with positive urine nitrite test, positive urine leukocyte esterase reaction and renal scarring (p = 0.0001, p = 0.0001, p = 0.04, respectively) whereas was not correlated to leukocytosis and positive CRP level in serum. Urine MMP-9/NGAL/cr can be used as a diagnostic biomarker for UTI in children. Identification of NGAL-MMP-9/cr levels in the urine of suspected UTI patients may also be useful to differentiate between contamination and infection and for monitoring of treatment response in children.  相似文献   
16.
17.
AIM: Intravenous iron therapy is an accepted treatment for patients receiving hemodialysis and continuous ambulatory peritoneal dialysis (CAPD). Studies have found enhanced oxidative stress in hemodialysis patients receiving intravenous iron, but there are no clinical data for CAPD patients. The aim of the current study was to investigate the effect of 100 mg of intravenous iron-sucrose on the erythrocyte (RBC) antioxidant enzymes (namely, superoxide dismutase [SOD], catalase [CAT], and glutathione peroxidase [GSHPx]) and plasma malondialdehyde (MDA), an oxidant molecule, in CAPD patients. METHODS: Twelve CAPD patients receiving maintenance intravenous iron-sucrose were recruited. After a 12-hour fast, blood samples were taken for hemoglobin, iron, ferritin, and high-sensitivity C-reactive protein (hsCRP), and for baseline activities of erythrocyte antioxidant enzymes (i.e., SOD, CAT, GSHPx) and the plasma oxidant molecule, MDA. 100 mg iron-sucrose was infused over 30 minutes. Blood samples taken during (i.e., 15 minutes after commencement of infusion) and after (i.e., at 30 minutes, 60 minutes, and 6 hours after commencement) the infusion were taken for measurement of plasma iron, ferritin, TSAT, RBC SOD, CAT, GSHPx, and plasma MDA. RESULTS: Plasma iron and transferrin saturation elevated significantly during infusion (p < 0.05). There was no significant change in erythrocyte SOD, CAT, GSHPx, or in MDA activities. There was a reduction of GSHPx activity at the 30th minute (from 153.69 +/- 66.69 to 123.68 +/- 25.50 mU/mL), but it was not statistically significant. The patients were grouped according to baseline ferritin (100-400 and 400-800 ng/mL); 60th-minute MDA was significantly higher in the latter group (p < 0.05). There was no correlation between hsCRP and oxidant-antioxidant balance. No correlation was noted between RBC antioxidant enzymes or plasma oxidant molecule and ferritin levels. CONCLUSION: There are no acute deteriorating effects from a 100 mg of intravenous iron-sucrose in CAPD patients with optimal iron stores. This dose may be applied safely in CAPD patients.  相似文献   
18.

Background

Multifocal breast cancers (MFBCs) present a challenge to surgeons. Although its feasibility is still controversial, breast-conserving surgery (BCS) is not contraindicated for MFBCs. The investigators retrospectively evaluated the feasibility of BCS and reviewed histopathologic findings in patients with MFBC.

Methods

A total of 222 patients with MFBC who were treated with either BCS (119 patients) or mastectomy (103 patients) at a single institution between January 2002 and December 2011 were retrospectively evaluated.

Results

The median follow-up time was 55 months (range, 10 to 102 months). Lymphovascular invasion and lymph node involvement were significantly less frequent in the BCS group (48.8% vs 62.2% for lymphovascular invasion, P = .04; 52.1% vs 71.8% for lymph node involvement, P = .002). There were no differences in local recurrence rates between the 2 groups. The overall survival rates were 92% in the BCS group and 72% in the mastectomy group (P = .000).

Conclusions

BCS is a feasible and safe procedure for the removal of multifocal tumors. Extended lymphovascular invasion is associated with mortality in patients who undergo mastectomy.  相似文献   
19.

Purpose

Humeral capitellum fractures comprise approximately 1% of all elbow fractures. In this study, we examined the clinical, radiographic, and functional outcomes following operative stabilization of Bryan and Morrey type IV fractures of the capitellum in adolescents. We applied headless cannulated screws in a posteroanterior direction without damaging the articular cartilage surface of the fractures.

Methods

Eight adolescent patients (six male, two female) with a mean age of 15 ± 2.1 years (range 13–18 years) were treated for type IV (McKee) humerus capitellum fractures. In the preoperative radiological evaluation, anteroposterior and lateral radiographs and computed tomography (CT) images were performed. A lateral surgical approach was used, and cannulated fully threaded headless screws were applied in a posteroanterior direction as fixation materials in the fracture reduction. The Mayo Elbow Performance Score was used in the evaluation of elbow joint functions.

Results

Patients were followed up for a mean of 24.6 months. Fracture union was achieved at a mean of 5 ± 0.92 weeks (range 4–6 weeks). The mean elbow extension flexion arc was 135° ± 13.47° (range 110°–150º) and the mean pronation supination arc was 156° ± 4.43° (150°–160°). In one patient, there was nonconformity in the humerus trochlea and in another patient, there was keloid formation on the surgical scar. All patients attained excellent results according to the Mayo Elbow Performance Score.

Conclusions

In the treatment of type IV capitellum fractures in adolescents, open reduction with a lateral surgical approach and fixation using posteroanterior directed, cannulated, fully threaded, headless screws is a reliable method to achieve a pain-free functional elbow joint.  相似文献   
20.
The aim of this randomized, parallel, controlled clinical trial was to examine the clinical and biochemical efficacy of diode laser as an adjunct to scaling and root planing (SRP). Thirty chronic periodontitis patients were randomly assigned into two groups to receive SRP alone (control) or SRP followed by diode laser (test). Plaque index, gingival index, bleeding on probing, probing depth, and clinical attachment level were measured at baseline and at 1, 3, and 6 months after treatment. The gingival crevicular fluid levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), matrix metalloproteinase-1 (MMP-1), matrix metalloproteinase-8 (MMP-8) and tissue inhibitor matrix metalloproteinase-1 (TIMP-1) were analyzed by enzyme-linked immunosorbent assay. Test group showed significantly a better outcome compared to the control group in full-mouth clinical parameters. MMP-1, MMP-8, and TIMP-1 showed significant differences between groups after treatment compared to baseline (p?<?0.05). The total amount of IL-1β, IL-6, MMP-1, MMP-8, and TIMP-1 decreased (p?<?0.05) and IL-8 increased after treatment in both test and control groups (p?<?0.05). Diode laser provided significant improvements in clinical parameters and MMP-8 was significantly impacted by the adjunctive laser treatment at first month providing an insight to how lasers can enhance the outcomes of the nonsurgical periodontal therapy.  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