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   2692篇
  免费   105篇
  国内免费   22篇
耳鼻咽喉   112篇
儿科学   163篇
妇产科学   91篇
基础医学   172篇
口腔科学   71篇
临床医学   182篇
内科学   559篇
皮肤病学   30篇
神经病学   256篇
特种医学   114篇
外科学   725篇
综合类   34篇
预防医学   34篇
眼科学   72篇
药学   90篇
中国医学   1篇
肿瘤学   113篇
  2024年   2篇
  2023年   16篇
  2022年   17篇
  2021年   52篇
  2020年   38篇
  2019年   56篇
  2018年   57篇
  2017年   35篇
  2016年   90篇
  2015年   96篇
  2014年   105篇
  2013年   138篇
  2012年   176篇
  2011年   150篇
  2010年   106篇
  2009年   93篇
  2008年   202篇
  2007年   233篇
  2006年   211篇
  2005年   226篇
  2004年   196篇
  2003年   175篇
  2002年   139篇
  2001年   40篇
  2000年   31篇
  1999年   24篇
  1998年   23篇
  1997年   10篇
  1996年   11篇
  1995年   8篇
  1994年   6篇
  1993年   5篇
  1992年   4篇
  1991年   12篇
  1990年   12篇
  1989年   7篇
  1988年   5篇
  1984年   4篇
  1983年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1966年   2篇
排序方式: 共有2819条查询结果,搜索用时 15 毫秒
91.
Basal cell adenoma (BCA) is a rare benign epithelial tumor of the salivary gland. BCA is seen most frequently in the parotid gland and less commonly in the submandibular gland and minor glands of the upper lips, oral cavity, and hard palate. Salivary gland tumors are observed as single tumors in one salivary gland. Double or multiple tumors of the salivary gland tumors are unusual and metachronous or bilateral salivary gland tumors are more observed than synchronous or unilateral tumors. The most commonly seen multiple tumor unilaterally or bilaterally is the Warthin's tumor. A 65-year-old woman with a painful, slowly enlarging mass in front of the left ear, which was present for 6 months, was evaluated. Physical examination revealed two solid and well-delineated masses in the preauricular region, which were 1.5 x 1 cm in diameter and in the tail of the parotid gland, which is 2.5 x 2 cm in diameter. Excision of the superficial lobe of the parotid gland was performed. The macroscopic examination of the specimen showed the two discrete nodular masses. Histologic examination of the two nodular solid lesions was reported as BCA. Multiple synchronous nonmembranous-type BCAs of the unilateral parotid gland is a rare entity. More extensive excision of the parotid gland tumor, careful macroscopic perioperative examination of the surgical specimen, and histologic evaluation of all surgical specimens might be necessary for reducing revision operations and surgical complications.  相似文献   
92.
The aim of this study was to investigate the diagnostic value of serum G protein–coupled oestrogen receptor (GPER) levels and their correlation with semen parameters in men with infertility. The participants were divided into two groups as follows: 76 fertile control men (Group 1) and 77 infertile men (Group 2). Semen analysis, hormonal evaluation, serum GPER level and scrotal ultrasound of the participants were evaluated. Follicle-stimulating hormone and total testosterone levels were not significantly different between the groups (p = .413 and p = .535 respectively). The oestradiol level in Group 1 was significantly lower than that in Group 2 (p < .001). The serum GPER level was found to be significantly higher in Group 1 than that of Group 2 (p < .001). GPER levels were positively correlated with the total sperm count, sperm concentration, motility and morphology in Group 2 (r = 0.303, 0.345, 0.260 and 0.322, respectively, p < .001). In this study, GPER levels were positively correlated with sperm parameters, and it was hypothesised that the decrease in GPER expression might be associated with male infertility by adversely affecting spermatogenesis.  相似文献   
93.
Aim of the workTo investigate promoter methylation of matrix metalloproteinase-3 (MMP-3) and interleukin-16 (IL-16) genes with the expression of miRNA-93-5p and miRNA-4668-5p which target these genes in rheumatoid arthritis (RA), respectively.Patients and methodsThe study included 49 RA patients and 38 healthy controls. Promoter methylation of MMP-3 and IL-16 was analyzed by methylation-specific PCR. The expression of miRNA-93-5p and miRNA-4668-5p were determined. Disease activity score (DAS28) was assessed.ResultsThe 49 patients (38 female, 11 male) mean age was 50.4 ± 10.5 years and disease duration of 9.1 ± 7.4 years. The mean DAS28 was 3.9 ± 1.4. The MMP-3 gene methylation frequency was significantly lower in patients (n = 37;75.5%) compared to control (n = 37;97.4%) (p = 0.004) while they were comparable for IL-16 gene (n = 46;93.9% vs n = 37;97.4%)(p = 0.45). The relative normalized expression of miRNA-93-5p and miRNA-4668-5p were significantly increased (p < 0.001) in patients (2.28 ± 3.71 and 2.47 ± 4.17-fold) compared to controls (1.12 ± 0.18 and 1.28 ± 0.53-fold) and both tended to decrease with high disease activity (r =  ? 0.104, p = 0.52; r = ?0.24, p = 0.15, respectively). There was no significant difference of miRNA-93-5p (p = 0.45), and miRNA-4668-5p (p = 0.26) expressions between patients receiving treatment and those not. A negative correlation was observed between disease activity and change in expression levels of miRNA-93-5p (r = ?0.104, p = 0.52) and miRNA-4668-5p (r = ?0.24, p = 0.15). The ROC curve analysis of target miRNAs showed the diagnostic potential of miRNA-93-5p and miRNA-4668-5p (p = 0.003 and p < 0.001 respectively).ConclusionsThe methylation status of MMP-3 promoter and expression levels of miRNA-93-5p and miRNA-4668-5p could be useful biomarkers for the pathogenesis of RA and might reflect disease activity.  相似文献   
94.
95.

Background

Intragastric band migration is an unusual but major complication of gastric banding. We review our experience with endoscopic removal of eroded gastric bands.

Methods

We retrospectively evaluated the cases of 110 morbidly obese patients who underwent adjustable gastric banding between 2005 and 2012 to identify those who experienced band erosion. To remove the migrated band, we used an endoscopic approach with a Gastric Band Cutter.

Results

Band or tube erosion occurred in 14 patients (12.7%). The median time interval from the initial gastric band placement to the diagnosis of band erosion was 32 (range 18–52) months. Upper abdominal pain, port site infection, loss of restriction and weight regain were the most common symptoms. We used the Gastric Band Cutter to remove the band endoscopically. It was able to cut the band successfully in all but 1 patient, in whom twisting of the cutting wire required conversion from endoscopy to laparotomy. In 2 patients, the band, after being cut, was locked in the gastric wall and required laparotomic removal. In 1 patient, we performed surgery for intragastric penetration of the connecting tube broken close to the band.

Conclusion

The Gastric Band Cutter was successful in dividing the band in all but 1 patient, although we could not always complete the procedure endoscopically. Endoscopic removal seems to be effective and safe for band erosion.  相似文献   
96.
Many techniques are described for the ligation of a difficult cystic duct (CD). The aim of this study is to assess the effectiveness and safety of stapling of a difficult CD in acute cholecystitis using Endo-GIA. From January 2008 to June 2012, 1441 patients with cholelithiasis underwent laparoscopic cholecystectomy (LC) at the Department of General Surgery, Haydarpasa Numune Education and Research Hospital. Of these, 19 (0.62%) were identified as having a difficult CD and were ligated using an Endo-GIA stapler. All patients were successfully treated with a laparoscopic approach. The length of hospital stay was 3.4 days. There were umbilical wound infections in 4 patients (21%). The length of follow-up ranged from 1.0 to 50.4 months. In conclusion, Endo-GIA is a safe and easy treatment method for patients with a dilated and difficult CD. The cystic artery should be isolated and ligated if possible before firing the Endo-GIA stapler. If isolation and stapling are not possible, fibrin sealant can be applied to avoid bleeding. The vascular Endo-GIA can be applied in a large CD, but for acute cholecystitis with an edematous CD, the Endo-GIA roticulator 4.8 or 3.5 stapler is preferred.Key words: Cholecystectomy, Endo-GIA, Acute cholecystitis, StaplerAfter the introduction of laparoscopic cholecystectomy (LC) in 1987,1 LC replaced open cholecystectomy as the gold standard for the treatment of cholelithiasis in international guidelines.2 LC was initially considered to be contraindicated for acute gallbladder inflammation, but it is currently a common procedure for acute cholecystitis.Some of the difficult situations a surgeon is likely to face during the performance of a laparoscopic cholecystectomy include anatomic anomalies such as a sessile gallbladder or short cystic duct and pathologic entities such as an empyema, Mirizzi syndrome, or a frozen Calot''s triangle secondary to infection and fibrosis.3It is suggested that laparoscopic surgery should be carried out within 72 hours from the onset of the symptoms because after that time there are higher rates of conversion to open procedures, increased risks of complications, and longer operative times.46 The generally accepted procedure in patients whose symptoms started 72 hours before admission is to “cool down” the patient with appropriate medical therapy and to perform LC after a period of 6 to 12 weeks.7,8 This approach aims to avoid a potentially more difficult cholecystectomy during an emergency admission and to avoid the difficulties of access to an emergency room.9,10 However, more than 20% of patients may fail to respond to conservative treatment and require an urgent and rather more difficult cholecystectomy, and a further 25% of patients will require readmission with a severe acute complication of cholelithiasis while awaiting a cholecystectomy.11,12 The scar formation, distortion, and organized adhesions around the gallbladder occurring secondary to the chronic inflammation in Calot''s triangle make the dissection difficult. The cystic duct (CD) is sometimes edematous, fibrous, or enlarged owing to inflammation and adhesions in acute cholecystitis and may be difficult to manage. Several methods were proposed for ligating the CD, including titanium or absorbable endoclip, endoloop, tie, ultrasonic or bipolar sealer, and the Endo-GIA stapler (Covidien, Mansfield, Massachusetts).1319This study proposes an effective, safe, and easy procedure for the stapling of dilated or difficult CD using the Endo-GIA.  相似文献   
97.
98.
99.

INTRODUCTION

Atypical presentations of appendix have been reported including backache, left lower quadrant pain and groin pain from a strangulated femoral hernia containing the appendix. We report a case presenting an epigastric pain that was diagnosed after computed tomography as a perforated appendicitis on intestinal malrotation.

PRESENTATION OF CASE

A 27-year-old man was admitted with a three-day history of epigastric pain. Physical examination revealed tenderness and defense on palpation of epigastric region. There was a left subcostal incision with the history of diaphragmatic hernia repair when the patient was 3 days old. He had an intestinal malrotation with the cecum fixed at the epigastric region and the inflamed appendix extending beside the left lobe of liver.

DISCUSSION

While appendicitis is the most common abdominal disease requiring surgical intervention seen in the emergency room setting, intestinal malrotation is relatively uncommon. When patients with asymptomatic undiagnosed gastrointestinal malrotation clinically present with abdominal pain, accurate diagnosis and definitive therapy may be delayed, possibly increasing the risk of morbidity and mortality.

CONCLUSION

Atypical presentations of acute appendicitis should be kept in mind in patients with abdominal pain in emergency room especially in patients with previous childhood operation for diaphragmatic hernia.  相似文献   
100.
An 83-year-old man presented with an unusually severe case of rhinophyma. Giant rhinopyhma is very rare in literature. The giant lesion was widely excised using sharp surgical incision and coblation assisted surgery. Using direct coblation to the nasal dorsum may cause edema in the surrounding tissue. There was minimal edema in surrounding tissue using this technique. A full thickness-skin graft was applied after excision. Cosmetic and functional postoperative results were satisfactory.KEY WORDS: Coblation, giant, rhinophyma  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