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   3778篇
  免费   136篇
  国内免费   27篇
耳鼻咽喉   176篇
儿科学   79篇
妇产科学   102篇
基础医学   549篇
口腔科学   28篇
临床医学   342篇
内科学   1042篇
皮肤病学   12篇
神经病学   243篇
特种医学   115篇
外科学   437篇
综合类   29篇
一般理论   3篇
预防医学   175篇
眼科学   70篇
药学   290篇
中国医学   2篇
肿瘤学   247篇
  2024年   2篇
  2023年   18篇
  2022年   128篇
  2021年   240篇
  2020年   65篇
  2019年   104篇
  2018年   134篇
  2017年   82篇
  2016年   98篇
  2015年   112篇
  2014年   163篇
  2013年   216篇
  2012年   313篇
  2011年   349篇
  2010年   166篇
  2009年   108篇
  2008年   231篇
  2007年   235篇
  2006年   264篇
  2005年   221篇
  2004年   221篇
  2003年   186篇
  2002年   134篇
  2001年   15篇
  2000年   7篇
  1999年   13篇
  1998年   14篇
  1997年   9篇
  1996年   10篇
  1995年   9篇
  1994年   5篇
  1993年   6篇
  1992年   7篇
  1991年   5篇
  1990年   11篇
  1989年   7篇
  1988年   5篇
  1987年   3篇
  1985年   2篇
  1984年   2篇
  1981年   3篇
  1980年   2篇
  1978年   3篇
  1977年   2篇
  1976年   1篇
  1975年   3篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有3941条查询结果,搜索用时 484 毫秒
131.
132.

Purpose

Remaining urachal anomalies are seldom found but can result in long-standing recurrent symptoms and repeated surgery. In this single-centre study, we evaluated the laparoscopic approach of excision of the urachus leaving the umbilicus untouched.

Methods

Twenty-one patients were operated on for persisting symptomatic urachal anomalies between 1998 and 2011. Patients included 8 males and 13 females (mean 28.5 years, range 15–72 years). Patients’ histories, surgical data and demographic data were prospectively collected and analysed. During follow-up, patients were evaluated using the total body image and cosmesis questionnaire (BIQ).

Results

Excision of the urachus was carried out in 18 cases in a laparoscopic three-trocar technique and in 3 cases using single-site surgery. In all cases, the infected umbilicus was left untouched. Mean surgical time of all procedures was 55.7 min (31–106 min). Histopathology confirmed an urachal anomaly in all cases. The former discharging or infected umbilicus healed without any complications. Sixteen patients could be included for the BIQ. Total body image score after surgery was 5.49 with a score of 5.0 being the most satisfactory result possible. The total cosmetic score was 21.37 close to the maximum score of 24.

Conclusions

The laparoscopic treatment of urachal anomalies using a three-trocar technique or the single-site surgery technique is both safe and effective. In our opinion, the excision of the umbilicus should be avoided. It simplifies the procedure and leads to satisfactory cosmetic results.  相似文献   
133.
Dual-energy X-ray absorptiometry (DXA) method is widely used in pediatrics in the study of bone density and body composition. However, there is a limit to how precise DXA can estimate bone and body composition measures in children. The study was aimed to (1) evaluate precision errors for bone mineral density, bone mass and bone area, body composition, and mechanostat parameters, (2) assess the relationships between precision errors and anthropometric parameters, and (3) calculate a “least significant change” and “monitoring time interval” values for DXA measures in children of wide age range (5–18 yr) using GE Lunar Prodigy densitometer. It is observed that absolute precision error values were different for thin and standard technical modes of DXA measures and depended on age, body weight, and height. In contrast, relative precision error values expressed in percentages were similar for thin and standard modes (except total body bone mineral density [TBBMD]) and were not related to anthropometric variables (except TBBMD). Concluding, due to stability of percentage coefficient of variation values in wide range of age, the use of precision error expressed in percentages, instead of absolute error, appeared as convenient in pediatric population.  相似文献   
134.
The authors describe the use of bone cement containing calcium phosphate for vertebroplasty of the cavity in the base of odontoid process. A 23-year-old female patient was operated on by incision in lateral cervical area (anterior open access). After a blunt dissection, the working cannula (Kyphon) was introduced under fluoroscopic guidance through the C2 vertebral body to the cavity in the base of the odontoid process. Intraoperatively biopsy of the lesion was taken and histopathological examination excluded the presence of neoplasm. The cavity, presumably haemangioma, was successfully filled with calcium phosphate bone cement KyphOs? FS (Kyphon). The proper filling without paravertebral cement leak was confirmed by postoperative computed tomography (CT). The CT and magnetic resonance imaging performed 9 months after the procedure showed that cement was still present in the cavity. This is the first use of calcium phosphate cement to conduct the vertebroplasty of C2 vertebra.  相似文献   
135.
PURPOSETo report the outcomes for 76 patients with penile cancer treated with high-dose-rate brachytherapy (HDR-BT) at a single institution.METHODSSeventy-six patients with penile cancer treated with HDR-BT in our department between October 1998 and September 2018 were analyzed. Seventy underwent interstitial HDR-BT (fractionation dose range of 3–3.5 Gy given twice a day with an interval of at least six hours between the fractions), and six underwent superficial treatment with mold applicators (fractionation dose range of 4–7 Gy given once or twice a week).RESULTSMedian follow-up was 76 months (7–204 months). In the whole group, 22/76 local failures (28.9%) were observed: 14/76 (18.4%) local recurrences and 8/76 (10.5%) cases of persistent disease. Median time to recurrence was 24 months (9–54 months). Inguinal lymph node metastases were observed in 18/76 cases (23.7%). Distant metastases occurred in 12/76 (15.8%) cases. Patients with local recurrence and persistent disease underwent salvage penectomies, except four who refused surgery and underwent a second course of interstitial HDR-BT. Five- and 10-year cause-specific survival were 85.0% and 77.8%, respectively. Local control at 5 and 10 years was 65.6%. Five- and 10-year penile preservation were 69.5% and 66.9%, respectively. There was no G3 or G4 acute toxicity. One urethral stenosis (1.3%) occurred in a patient with a T3 tumor and was treated successfully with dilatation.CONCLUSIONSHDR-BT provides good local control of penile cancer and is a good option for penis preservation therapy and in our experience achieves a penile preservation rate at 10 years of 66.9%.  相似文献   
136.
Steroid sulfatase (STS) is responsible for the hydrolysis of biologically inactive sulfated steroids into their active un‐sulfated forms and promotes the growth of various hormone‐dependent cancers (e.g., breast cancer). Therefore, the STS enzyme is a promising therapeutic target for the treatment of steroid‐sensitive cancers. Herein, we report the synthesis and biological evaluation of sulfamate analogs as potential STS inhibitors based on N‐acylated tyramines that contain C–F bonds. The inhibitory effects of the analogs were tested using STS isolated from human placenta. Of the analogs tested, 4‐(2‐perfluoroundecanoylaminoethyl)‐phenyl sulfamate, 5r , demonstrated the greatest inhibitory effect, with an IC50 value of 2.18 μm (IC50 value of 2.13 μm for coumarin‐7‐O‐sulfamate was used as a reference). These findings were supported by the results our computational analyses performed using molecular docking techniques.  相似文献   
137.
Long‐term hemodialysis catheter dwell time in the central vein predisposes to fibrin sheath development, which subsequently causes catheter malfunction or occlusion. In very rare cases, the catheter can be overgrown with fibrin and rigidly connected with the vein or heart structures. This makes its removal almost impossible and dangerous because of the possibility of serious complications, namely vein and heart wall perforation, bleeding, or catheter abruption in deep tissues. We describe two cases in which standard retrieval of long‐term catheters was not possible. Balloon dilatation of catheter lumens was successfully used to increase the catheter diameter with simultaneous tearing of the fibrin sheath surrounding it. This allowed the catheter to be set free safely. Based on this experience, we present recent literature and our point of view.  相似文献   
138.
139.
140.
Heart failure (HF) and obesity are major public health problems. Studies have shown that obesity may increase the risk of developing new HF but after patients have developed HF, obesity may be associated with improved outcomes. This paradoxical association of obesity with HF remains poorly understood. It is believed that the obesity paradox may in part be due to the inherent limitations of body mass index (BMI) as a measure of obesity. BMI may not appropriately measure important components of body mass like body fat, fat distribution, lean body mass, and body fluid content and may not be ideal for examining the relationship of body composition with health outcomes. Differentiating between body fat and lean body mass may explain some of the paradoxical association between higher BMI and better prognosis in patients with HF. Paradoxical outcomes in HF may also be due to phenotypes of obesity. Future studies need to develop and test metrics that may better measure body composition and may serve as a better tool for the estimation of the true association of obesity and outcomes in HF and determine whether the association may vary by obesity phenotypes.
  • KEY MESSAGES
  • Obesity predisposes to heart failure in all age groups. But obesity in heart failure is an area of controversy, because of obesity paradox, the apparent protective effect of overweight and mild obesity on mortality after development of heart failure.

  • Traditional markers of obesity do not measure different components of body weight like muscle mass, fat, water, and skeletal weight. Body Mass Index in heart failure subjects does not measure accurately body fat or fluid retention. So new markers of obesity like visceral adiposity index, body composition analysis, sarcopenic status assessment may be helpful in the assessment of heart failure outcomes.

  • Different phenotypes of obesity may be responsible for the different morbidity, mortality as well as therapeutic outcomes in heart failure.

  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