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   2901篇
  免费   167篇
  国内免费   17篇
耳鼻咽喉   17篇
儿科学   53篇
妇产科学   51篇
基础医学   369篇
口腔科学   122篇
临床医学   464篇
内科学   446篇
皮肤病学   44篇
神经病学   208篇
特种医学   69篇
外科学   320篇
综合类   67篇
一般理论   9篇
预防医学   319篇
眼科学   50篇
药学   274篇
中国医学   15篇
肿瘤学   188篇
  2023年   23篇
  2022年   25篇
  2021年   59篇
  2020年   44篇
  2019年   68篇
  2018年   61篇
  2017年   54篇
  2016年   53篇
  2015年   63篇
  2014年   84篇
  2013年   146篇
  2012年   208篇
  2011年   227篇
  2010年   156篇
  2009年   109篇
  2008年   195篇
  2007年   191篇
  2006年   174篇
  2005年   192篇
  2004年   174篇
  2003年   172篇
  2002年   139篇
  2001年   41篇
  2000年   26篇
  1999年   31篇
  1998年   28篇
  1997年   29篇
  1996年   34篇
  1995年   23篇
  1994年   15篇
  1993年   20篇
  1992年   22篇
  1991年   13篇
  1990年   14篇
  1989年   18篇
  1988年   25篇
  1987年   15篇
  1986年   15篇
  1985年   15篇
  1984年   9篇
  1983年   11篇
  1982年   8篇
  1981年   10篇
  1980年   7篇
  1979年   6篇
  1978年   7篇
  1977年   6篇
  1972年   2篇
  1969年   3篇
  1966年   2篇
排序方式: 共有3085条查询结果,搜索用时 15 毫秒
81.

Background

Injury sustained in rural areas has been shown to carry higher mortality rates than trauma in urban settings. This disparity is partially attributed to increased distance from definitive care and underscores the importance of proper primary trauma management prior to transfer to a trauma facility. The purpose of this study was to assess Advanced Trauma Life Support (ATLS) guideline adherence in the management of adult trauma patients transferred from rural hospitals to a level I facility.

Methods

We performed a retrospective analysis of all adult major trauma patients transferred ≥50 km from an outlying hospital to a level I trauma centre from 2007 through 2009. Transfer practices were evaluated using ATLS guidelines.

Results

646 patients were analyzed. Mean age was 40.5 years and 94% sustained blunt injuries with a median Injury Severity Score (ISS) of 22. Median transport distance was 253 km. Among all patients, there were notable deficiencies (<80% adherence) in 8 of 11 ATLS recommended interventions, including patient rewarming (8% adherence), chest tube insertion (53%), adequate IV access (53%), and motor/sensory exam (72%). Patients with higher ISS scores, and those transferred by air were more likely to receive ATLS recommended interventions.

Conclusions

Key aspects of ATLS resuscitation guidelines are frequently missed during transfer of trauma patients from the periphery to level I trauma centres. Comprehensive quality improvement initiatives, including targeted education, telemedicine and trauma team training programmes could improve quality of care.  相似文献   
82.
After studying the anatomy of 10 fresh cadavers, we developed a technique for the treatment of the cervical area during face lifts. We called this technique PLATYSMA-SUSPENSION and PLATYSMA-PEXY rather than plication. This technique consists of suspending the free edge of the platysma muscle and fixing it to a resistant tissue close to the earlobe (Loré’s fascia or temporo-parotid fascia). The anterior triangle of the neck was well defined and there was no need to undermine the platysma muscle because of a perfect sliding plane between the platysma and sternocleidomastoid muscles. This technique is both simple and effective. It generates long-lasting results, without the inconveniences or complications associated with other techniques.

MATERIALS AND METHODS:

Ten fresh cadavers (ie, 20 hemifaces) were subjected to the proposed technique. They were photographed and filmed at all stages.Ten more cadavers were dissected to study the submental area and we discovered that the best way to recreate the cervico mental angle and to rebuild the floor of the mouth is to use a digastric corset so that we could rebuild the retaining ligaments between the platysma/digastric and mylohyoïd muscles.More than 100 patients were operated by the senior author; they underwent platysma-suspension and platysma-pexy of the fascia described by Loré; associated in difficult necks (Knize 3 and 4 necks) with the digastric corset. The patients were followed-up for a minimum of 12 months.

CONCLUSION:

PLATYSMA-SUSPENSION and PLATYSMA-PEXY in the fascia described by Loré is an extremely long-lasting and effective technique in cervical lifting. It generates impressive results, even in the most inferior portion of the neck. It redefines the entire anterior triangle, especially the sternocleidomastoid muscle and the mandibular contours. Furthermore, PLATYSMA-SUSPENSION minimizes the risk of nerve injury and hematoma by preventing deep and unnecessary dissections because the superficial cervical fascia has a perfect sliding plane between the platysma and the deepest structures of the neck.In difficult necks, we do associate a digastric corset using a submental incision.Pre-op botulinum toxin injections appears to be of great interest leaving the muscle at rest during the post-operative phase.Can J Plast Surg. 2013 Winter; 21(4): 253.

2: Facial Palsy: Lengthening Temporalis Myoplasty and Smile Reanimation

D LabbéAuthor information Copyright and License information DisclaimerCaen, FranceCopyright ©2013 Canadian Society of Plastic Surgeons. All rights reserved  相似文献   
83.
Maintaining and improving fitness are associated with a lower risk of premature death from cardiovascular disease. Patients with schizophrenia are known to exercise less and have poorer health behaviors than average. Physical fitness and physiological regulation during exercise tasks have not been investigated to date among patients with schizophrenia. We studied autonomic modulation in a stepwise exhaustion protocol in 23 patients with schizophrenia and in matched controls, using spirometry and lactate diagnostics. Parameters of physical capacity were determined at the aerobic, anaerobic, and vagal thresholds (VT), as well as for peak output. VT was correlated with psychopathology, as assessed by the Positive and Negative Syndrome Scale, with the inflammatory markers IL-1β, IL-6, and TNF-α and with peak output. The MANOVA for heart and breathing rates, as well as for vagal modulation and complexity behavior of heart rate, indicated a profound lack of vagal modulation at all intensity levels, even after the covariate carbon monoxide concentration was introduced as a measure of smoking behavior. Significantly decreased physical capacity was demonstrated at the aerobic, anaerobic, and VT in patients. After the exercise task, reduced vagal modulation in patients correlated negatively with positive symptoms and with levels of IL-6 and TNF-α. This study shows decreased physical capacity in patients with schizophrenia. Upcoming intervention studies need to take into account the autonomic imbalance, which might predispose patients to arrhythmias during exercise. Results of inflammatory parameters are suggestive of a reduced activity of the anti-inflammatory cholinergic pathway in patients, leading to a pro-inflammatory state.Key words: heart rate, physical exercise, respiration, schizophrenia, vagal threshold, cardiac death, inflammation, physical fitness  相似文献   
84.
85.
Patients with pathologic processes of the breast commonly present in the Emergency Department (ED). Familiarity with the imaging and management of the most common entities is essential for the radiologist. Additionally, it is important to understand the limitations of ED imaging and management in the acute setting and to recognize when referrals to a specialty breast center are necessary. The goal of this article is to review the clinical presentations, pathophysiology, imaging, and management of emergency breast cases and common breast pathology seen in the ED.  相似文献   
86.
The vitamin D‐deficient model, established in the C57BL/6 mouse after 8 weeks of feeding vitamin D‐deficient diets in the absence or presence of added calcium, was found associated with elevated levels of plasma parathyroid hormone (PTH) and plasma and liver cholesterol, and a reduction in cholesterol 7α‐hydroxylase (Cyp7a1, rate‐limiting enzyme for cholesterol metabolism) and renal Oat3 mRNA/protein expression levels. However, there was no change in plasma calcium and phosphate levels. Appraisal of the liver revealed an up‐regulation of mRNA expressions of the small heterodimer partner (Shp) and attenuation of Cyp7a1, which contributed to hypercholesterolemia in vitamin D‐deficiency. When vitamin D‐sufficient or D‐deficient mice were further rendered hypercholesterolemic with 3 weeks of feeding the respective, high fat/high cholesterol (HF/HC) diets, treatment with 1α,25‐dihydroxyvitamin D3 [1,25(OH)2D3], active vitamin D receptor (VDR) ligand, or vitamin D (cholecalciferol) to HF/HC vitamin D‐deficient mice lowered the cholesterol back to baseline levels. Cholecalciferol treatment partially restored renal Oat3 mRNA/protein expression back to that of vitamin D‐sufficient mice. When the protein expression of protein kinase C (PKC), a known, negative regulator of Oat3, was examined in murine kidney, no difference in PKC expression was observed for any of the diets with/without 1,25(OH)2D3/cholecalciferol treatment, inferring that VDR regulation of renal Oat3 did not involve PKC in mice. As expected, plasma calcium levels were not elevated by cholecalciferol treatment of vitamin D‐deficient mice, while 1,25(OH)2D3 treatment led to hypercalcemia. In conclusion, vitamin D‐deficiency resulted in down‐regulation of liver Cyp7a1 and renal Oat3, conditions that are alleviated upon replenishment of cholecalciferol.  相似文献   
87.
Vitamin D3 and the synthetic vitamin D analogs, 1α‐hydroxyvitamin D3 [1α(OH)D3], 1α‐hydroxyvitamin D2 [1α(OH)D2] and 25‐hydroxyvitamin D3 [25(OH)D3] were appraised for their vitamin D receptor (VDR) associated‐potencies as cholesterol lowering agents in mice in vivo. These precursors are activated in vivo: 1α(OH)D3 and 1α(OH)D2 are transformed by liver CYP2R1 and CYP27A1 to active VDR ligands, 1α,25‐dihydroxyvitamin D3 [1,25(OH)2D3] and 1α,25‐dihydroxyvitamin D2 [1,25(OH)2D2], respectively. 1α(OH)D2 may also be activated by CYP24A1 to 1α,24‐dihydroxyvitamin D2 [1,24(OH)2D2], another active VDR ligand. 25(OH)D3, the metabolite formed via CYP2R1 and or CYP27A1 in liver from vitamin D3, is activated by CYP27B1 in the kidney to 1,25(OH)2D3. In C57BL/6 mice fed the high fat/high cholesterol Western diet for 3 weeks, vitamin D analogs were administered every other day intraperitoneally during the last week of the diet. The rank order for cholesterol lowering, achieved via mouse liver small heterodimer partner (Shp) inhibition and increased cholesterol 7α‐hydroxylase (Cyp7a1) expression, was: 1.75 nmol/kg 1α(OH)D3 > 1248 nmol/kg 25(OH)D3 (dose ratio of 0.0014) > > 1625 nmol/kg vitamin D3. Except for 1.21 nmol/kg 1α(OH)D2 that failed to lower liver and plasma cholesterol contents, a significant negative correlation was observed between the liver concentration of 1,25(OH)2D3 formed from the precursors and liver cholesterol levels. The composite results show that vitamin D analogs 1α(OH)D3 and 25(OH)D3 exhibit cholesterol lowering properties upon activation to 1,25(OH)2D3: 1α(OH)D3 is rapidly activated by liver enzymes and 25(OH)D3 is slowly activated by renal Cyp27b1 in mouse.  相似文献   
88.
89.
90.

Background

The benefit of cytoreductive nephrectomy (CN) for overall survival (OS) is unclear in patients with synchronous metastatic renal cell carcinoma (mRCC) in the era of targeted therapy.

Objective

To determine OS benefit of CN compared with no CN in mRCC patients treated with targeted therapies.

Design, setting, and participants

Retrospective data from patients with synchronous mRCC (n = 1658) from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) were used to compare 982 mRCC patients who had a CN with 676 mRCC patients who did not.

Outcome measurements and statistical analysis

OS was compared and hazard ratios (HRs) adjusted for IMDC poor prognostic criteria.

Results and limitations

Patients who had CN had better IMDC prognostic profiles versus those without (favorable, intermediate, or poor in 9%, 63%, and 28% vs 1%, 45%, and 54%, respectively). The median OS of patients with CN versus without CN was 20.6 versus 9.5 mo (p < 0.0001). When adjusted for IMDC criteria to correct for imbalances, the HR of death was 0.60 (95% confidence interval, 0.52–0.69; p < 0.0001). Patients estimated to survive <12 mo may receive marginal benefit from CN. Patients who have four or more of the IMDC prognostic criteria did not benefit from CN. Data were collected retrospectively.

Conclusions

CN is beneficial in synchronous mRCC patients treated with targeted therapy, even after adjusting for prognostic factors. Patients with estimated survival times <12 mo or four or more IMDC prognostic factors may not benefit from CN. This information may aid in patient selection as we await results from randomized controlled trials.

Patient summary

We looked at the survival outcomes of metastatic renal cell carcinoma patients who did or did not have the primary tumor removed. We found that most patients benefited from tumor removal, except for those with four or more IMDC risk factors.  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