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   916篇
  免费   56篇
  国内免费   2篇
耳鼻咽喉   3篇
儿科学   8篇
妇产科学   11篇
基础医学   130篇
口腔科学   27篇
临床医学   54篇
内科学   216篇
皮肤病学   14篇
神经病学   65篇
特种医学   17篇
外科学   263篇
综合类   1篇
预防医学   42篇
眼科学   41篇
药学   36篇
中国医学   2篇
肿瘤学   44篇
  2022年   11篇
  2021年   17篇
  2020年   18篇
  2019年   19篇
  2018年   21篇
  2017年   12篇
  2016年   21篇
  2015年   25篇
  2014年   36篇
  2013年   51篇
  2012年   52篇
  2011年   57篇
  2010年   35篇
  2009年   39篇
  2008年   51篇
  2007年   52篇
  2006年   65篇
  2005年   64篇
  2004年   54篇
  2003年   52篇
  2002年   64篇
  2001年   14篇
  2000年   12篇
  1999年   11篇
  1998年   15篇
  1997年   10篇
  1996年   10篇
  1995年   3篇
  1993年   5篇
  1990年   5篇
  1989年   2篇
  1988年   4篇
  1987年   2篇
  1985年   3篇
  1983年   3篇
  1981年   3篇
  1980年   5篇
  1979年   2篇
  1978年   5篇
  1975年   2篇
  1974年   2篇
  1973年   3篇
  1972年   3篇
  1971年   2篇
  1970年   2篇
  1969年   3篇
  1968年   3篇
  1967年   3篇
  1966年   4篇
  1965年   3篇
排序方式: 共有974条查询结果,搜索用时 15 毫秒
31.
Introduction: In this study we examined oxidative stress and skeletal muscle damage resulting from acute strength, aerobic, or concurrent exercise in rats. Methods: The animals were divided into control (C), strength (SE), aerobic (AE), and combined (CE) exercise groups. They were euthanized at 3 different time‐points (6, 24, and 48 h) after acute exercise. Results: SE exercise rats had increased dichlorofluorescein oxidation at 6 h post‐exercise and decreased superoxide dismutase activity at all time‐points. Glutathione peroxidase activity and sulfhydryl levels were increased in the AE group at 48 h post‐exercise. Serum lactate dehydrogenase activity was increased in the SE and CE groups at 24 h and in the AE group at 48 h. Echo intensity was elevated at 24 h for all groups. Conclusions: Forty‐eight hours was sufficient for complete recovery from oxidative stress and muscle damage in the SE and CE groups, but not in the AE group. Muscle Nerve 50 : 79–86, 2014  相似文献   
32.
BackgroundThe global pandemic Coronavirus Disease 2019 (COVID-19) due to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is reported to be potentially severe in patients with morbid conditions. One common reported comorbidities is diabetes. We aimed in this study to precise the clinical characteristics and outcomes in a series of congolese diabetic patients affected by COVID-19 infection.Patients and methodsWe retrospectely studied from 256 COVID-19 patients, a cohort of 30 persons with previously known diabetes. The glycaemia controls have been obtained by plasma glucose assay. All patients have been tested positive to SARS-CoV-2 by RT-PCR method.ResultsThe COVID-19 diabetic patients represented 11,7% of all COVID-19 patients with confidence interval of 95% [7,77–15,65]. Older individuals and male sex were predominent. Dyspnea and sauration of oxygen < 90 were significatives and added risk factors were noted in 63.3% of patients, particulary hyperglycaemia with hypertension or obesity. The mortality rate at the percentage of 36.7% was more prevalent in patients with added comorbidities (30%) versus without comorbidities (6.7%).ConclusionCongolese COVID-19 diabetic patients of male sex and older age exhibiting arterial hypertension and obesity are the most exposed to severe COVID-19 and increasead mortality rate.  相似文献   
33.
Structural bone allografts often fracture due to their lack of osteogenic and remodeling potential. To overcome these limitations, we utilized allografts coated with recombinant adeno-associated virus (rAAV) that mediate in vivo gene transfer. Using beta-galactosidase as a reporter gene, we show that 4-mm murine femoral allografts coated with rAAV-LacZ are capable of transducing adjacent inflammatory cells and osteoblasts in the fracture callus following transplantation. While this LacZ vector had no effect on allograft healing, bone morphogenetic protein signals delivered via rAAV-caAlk2 coating induced endochondral bone formation directly on the cortical surface of the allograft by day 14. By day 28 there was evidence of remodeling of the new woven bone and massive osteoclastic resorption of the cortical surface of the rAAV-caAlk2-coated allografts only. Micro-CT analysis of rAAV-LacZ- vs rAAV-caAlk2-coated allografts after 42 days of healing demonstrated a significant increase in new bone formation (0.67 +/- 0.21 vs 2.49 +/- 0.40 mm(3); P < 0.005). Furthermore, the 3D micro-CT images of femurs grafted with rAAV-Alk2-coated allografts provided the first evidence that complete bridging of bone around a cortical allograft is possible. These results indicate that cell-free, rAAV-coated allografts have the potential to revitalize in vivo following transplantation.  相似文献   
34.

Background

Perforator flap techniques with conventional wound dressing have being extensively used in the management of soft-tissue defects. However; the flap's survival rate is not always guaranteed and the wound healing time always long. The aim of this study was to investigate the clinical effectiveness use of a freshly transplanted perforator flap in conjunction with Vacuum-assisted closure (VAC) for better clinical outcomes.

Methods

A prospective, randomized, effectiveness study comparing the clinical outcomes of VAC versus traditional wrap and bandages for the treatment of open wounds that required hospital admission and operative debridement using perforator flaps, was carried out from March 1, 2014 to March 31, 2016 at Wuhan University Zhongnan Hospital. Fifty-one eligible patients were randomized into two groups; study group (perforator flaps covered by VAC) and control group (perforator flaps covered by traditional wrap and bandages). The measured clinical endpoints included the time of the first post-operative dressing change, pain visual analogical scale, perforator flap infection rate, 95% perforator flap healing time and percentage of survived perforator flap.

Results

There was no statistically significant difference in the demographic profiles in the two cohorts. There were statistically significant differences in the clinical endpoints in the two groups (p < 0.001; p < 0.05, Table 2).

Conclusions

In summary, VAC combining with perforator flap technique, can diminish accumulated exudation of the transferring flap, protect against postoperative infection, prolong the interval between perforator flap relocation and first postoperative dressing change, decrease pain during removal of dressing, increase perforator flap survival rate, and shorten wound healing time, with a good aesthetic outcome, a good mobility and a satisfactory therapeutic result.  相似文献   
35.
Barnes B  Rodts GE  Haid RW  Subach BR  McLaughlin MR 《Neurosurgery》2002,51(5):1191-8; discussion 1198
OBJECTIVE: With the proliferation of implant types available for use in posterior lumbar interbody fusion (PLIF) procedures, the choices for surgeons have become increasingly complex. The goal of this study was to retrospectively review a series of 49 patients who underwent PLIF with the use of allograft cylindrical threaded cortical bone dowels (TCBDs) and allograft impacted wedges. Nerve root injury rates, fusion rates, and clinical outcomes of the allograft impacted wedge group are compared with those in the allograft cylindrical TCBD group. METHODS: We performed a retrospective chart and radiographic review of 49 patients. Twenty-seven patients underwent PLIF with impacted allograft wedges, and 22 patients underwent PLIF with allograft cylindrical TCBD. Permanent nerve root injury rates, fusion rates, and clinical outcomes were assessed on the basis of a minimum of 1 year of follow-up data in this nonconsecutive series. RESULTS: Permanent nerve root injuries in the impacted wedge and TCBD groups were documented with physical examinations conducted pre- and postoperatively. The cylindrical TCBD group showed a 13.6% rate of permanent nerve root injury, and the impacted wedge group demonstrated a 0% rate, and these rates were statistically significant (analysis of variance, P = 0.049). The fusion rate at a mean of 13.9 months of follow-up was 95.4% in patients in whom the cylindrical TCBD was implanted and 88.9% after a mean of 17.4 months of follow-up in patients in whom impacted wedges were used. The fusion rate difference between the TCBD and impacted wedge groups was not significant. The satisfactory outcome rate was 72.7% for the TCBD group and 85.1% for the impacted wedge group, and the impacted wedge group was found to have a significantly higher rate of satisfactory outcomes (P = 0.016, analysis of variance). Analysis of the patient outcomes in the TCBD and impacted wedge groups according to sex, mean length of follow-up, workman's compensation claim rate, and smoking habit yielded no significant difference. CONCLUSION: With a minimum of 1 year of follow-up in this nonconsecutive series of 49 patients, a comparison of the use of allograft TCBD versus allograft impacted wedges in PLIF procedures reveals a statistically significant increase in permanent nerve root injury rates with the use of cylindrical TCBD implants as compared with impacted allograft wedges. There is no difference between the two groups in terms of fusion rates, and clinical outcomes with the use of impacted wedges were significantly better.  相似文献   
36.
37.
Surgical Endoscopy - Benefits and cost-effectiveness of robotic approach for distal pancreatectomy (DP) remain debated. In this prospective study, we aim to compare the short-term results and real...  相似文献   
38.
39.
The grey level of co‐occurrence matrix (GLCM) is a texture analysis approach accounting for spatial distribution of the pixels from an image and can be a promising method for exercise‐induced muscle damage (EIMD) studies. We followed up the time changes of two GLCM texture parameters and echo intensity (EI) on ultrasound images after eccentric contractions. Thirteen untrained women performed two sets of ten elbow flexions eccentric contractions. Ultrasound images were acquired at baseline and 24 h, 48 h, 72 h and 96 h after exercise. Two GLCM texture parameters were calculated for the brachialis muscle: contrast (CON) and correlation (COR). Peak torque, EI, muscle thickness (MT) and soreness were measured. The peak torque and soreness decreased immediately after the intervention in comparison with all the measures. MT increased immediately after the intervention remaining for 72 h (P<0·05). Significant increases (P<0·05) were observed for COR (48, 72 and 96 h) and EI only at 72 and 96 h. The increasing COR represents high similarity between grey levels, which could be observed on US images after few days on eccentric training for elbow flexors.  相似文献   
40.
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