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   509篇
  免费   15篇
  国内免费   1篇
耳鼻咽喉   29篇
儿科学   19篇
妇产科学   12篇
基础医学   51篇
口腔科学   3篇
临床医学   57篇
内科学   86篇
皮肤病学   12篇
神经病学   37篇
特种医学   48篇
外科学   74篇
综合类   14篇
预防医学   21篇
眼科学   10篇
药学   19篇
肿瘤学   33篇
  2023年   1篇
  2022年   7篇
  2021年   9篇
  2020年   5篇
  2019年   10篇
  2018年   16篇
  2017年   12篇
  2016年   16篇
  2015年   18篇
  2014年   31篇
  2013年   30篇
  2012年   31篇
  2011年   32篇
  2010年   15篇
  2009年   22篇
  2008年   31篇
  2007年   28篇
  2006年   31篇
  2005年   27篇
  2004年   34篇
  2003年   19篇
  2002年   15篇
  2001年   5篇
  2000年   10篇
  1999年   4篇
  1998年   7篇
  1997年   3篇
  1996年   4篇
  1995年   5篇
  1994年   1篇
  1993年   3篇
  1992年   5篇
  1991年   2篇
  1990年   7篇
  1989年   4篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1983年   2篇
  1978年   1篇
  1977年   1篇
  1976年   2篇
  1973年   2篇
  1972年   1篇
  1971年   2篇
  1970年   3篇
  1969年   1篇
  1965年   1篇
排序方式: 共有525条查询结果,搜索用时 15 毫秒
11.
Morgagni hernia (MH) is the least common type of congenital diaphragmatic hernias. Although its course is often asymptomatic, it may be associated with various respiratory and gastrointestinal symptoms. We describe 7 children with MH during a 5-year period in three pediatric centers in Turkey. All children had acute or chronic respiratory symptoms; cough was the most frequent. The diagnosis was made by posterior-anterior (PA) and lateral chest X-rays. The PA chest X-rays showed a homogenous mass in 2 and a gas-filled cystic image in 3 children in the right cardiophrenic angle. A retrocardiac homogeneous density in one child, and bilateral consolidation in lower lung areas in another child were also seen. All lateral chest X-rays showed gas-filled bowel loops above the diaphragm. The diagnosis was confirmed by barium-contrast radiograph. Four patients had five additional anomalies, i.e., ventricular septal defect, right inguinal hernia, congenital hip dislocation, pectus carinatum, and obstruction of the uretero-pelvic junction. All of the hernias were repaired by an abdominal approach. There were no complications or recurrences during follow-up. In conclusion, MH should be considered in the differential diagnosis of cases of long-standing respiratory symptoms and/or when an unexplained radiological image, especially on the right cardiophrenic area, is present.  相似文献   
12.
Cholangiocellular carcinoma (CC) originates from topographically heterogeneous cholangiocytes. The cylindrical mucin-producing cholangiocytes are located in large bile ducts and the cuboidal non-mucin-producing cholangiocytes are located in ductules containing bipotential hepatic progenitor cells (HPCs). We investigated the clinicopathological and molecular features of 85 resected CCs (14 hilar CCs [so-called Klatskin tumor], 71 intrahepatic CCs [ICCs] including 20 cholangiolocellular carcinomas [CLCs], which are thought to originate from HPCs]) and compared these with the different cholangiocyte phenotypes, including HPCs. Immunohistochemistry was performed with biliary/HPC and hepatocytic markers. Gene expression profiling was performed in different tumors and compared with nonneoplastic different cholangiocyte phenotypes obtained by laser microdissection. Invasion and cell proliferation assay were assessed using different types of CC cell lines: KMC-1, KMCH-1, and KMCH-2. Among 51 ICCs, 31 (60.8%) contained only mucin-producing CC features (muc-ICCs), whereas 39.2% displayed histological diversity: focal hepatocytic differentiation and ductular areas (mixed-ICCs). Clinicopathologically, muc-ICCs and hilar CCs showed a predominantly (peri-)hilar location, smaller tumor size, and more lymphatic and perineural invasion compared with mixed-ICCs and CLCs (predominantly peripheral location, larger tumor size, and less lymphatic and perineural invasion). Immunoreactivity was similar in muc-ICCs and hilar CCs and in mixed-ICCs and CLCs. S100P and MUC1 were significantly up-regulated in hilar CCs and muc-ICCs compared with mixed-ICCs and CLCs, whereas NCAM1 and ALB tended to be up-regulated in mixed-ICCs and CLCs compared with other tumors. KMC-1 showed significantly higher invasiveness than KMCH-1 and KMCH-2. Conclusion: Muc-ICCs had a clinicopathological, immunohistochemical, and molecular profile similar to that of hilar CCs (from mucin-producing cholangiocytes), whereas mixed-ICCs had a profile similar to that of CLCs (thought to be of HPC origin), possibly reflecting their respective cells of origin.  相似文献   
13.
14.
The implementation of the Expanded Program of Immunization (EPI) in 1989 has dramatic impact on hepatitis B virus (HBV) infection in school children in Malaysia. A cross-sectional seroprevalence study of HBV infection in 190,077 school children aged 7–12 years from 1997 to 2003 showed a steady decline of HBV surfacce antigen (HBsAg) prevalence rate from 2.5% for children born in 1985 to 0.4% among school children born in 1996. The overall prevalence of HBsAg was 0.6%, 0.7% in males and 0.6% in females. Over 92.7% of school children had been vaccinated with HBV vaccine, in which 93.7% were vaccinated under the EPI and 6.3% on voluntary basis. The school children vaccinated under EPI had a 0.4% HBsAg carrier rate, which was significantly lower than school children vaccinated on a voluntary basis (HBsAg carrier rate 1.3%) and non-vaccinated school children (HBsAg carrier rate 2.7%), suggesting that HBV vaccination of infants was the most effective measure in preventing vertical transmission of HBV in the hyperendemic region.  相似文献   
15.
Intrahepatic cholestasis of pregnancy is a diagnosis of exclusion and presents with unexplained pruritus, abnormal liver function tests, and increased serum bile acid levels, particularly in the third trimester of pregnancy. Serum YKL-40 levels are increased in liver diseases and our aim was to investigate YKL-40 levels in pregnant women with ICP. 40 women with intrahepatic cholestasis of pregnancy and 40 healthy pregnant women were included in this cross-sectional study. Serum YKL-40 levels were measured in both groups and correlation analysis were performed between the YKL-40 and other liver function tests. Serum YKL-40 concentrations were higher in the intrahepatic cholestasis of pregnancy group than in the control group (103.46?±?53.03 vs. 57.60?±?30.30?ng/ml, p?=?.002). The cutoff YKL-40 serum concentration was 84.80?ng/ml for the diagnosis of intrahepatic cholestasis of pregnancy. There was no correlation between fasting bile acids and YKL-40 levels. However, there was a significant positive correlation between the YKL-40 levels and aspartate aminotransferase (r?=?0.22, p?=?.04) and alanine aminotransferase (r?=?0.24, p?=?.02). Raised YKL-40 levels might support the evidence on inflammatory processes in intrahepatic cholestasis of pregnancy.  相似文献   
16.
Cardiopulmonary bypass (CPB) contributes to the secretion of anti-inflammatory cytokines that mediate the inflammatory response observed during open heart surgery. In addition to many factors, type of anesthesia management affects immune response and central nervous system in cardiac surgery. The aim of this study was to assess the effect of propofol versus desflurane anesthesia on systemic immune modulation and central nervous system on patients undergoing coronary artery bypass grafting. Forty patients undergoing elective coronary artery bypass graft surgery with CPB were included in this prospective randomized study. Patients were allocated to receive propofol (n?=?20) or desflurane (n?=?20) for maintenance of anesthesia. The blood samples for IL-6, IL-8, TNF-α, and S100β were drawn just prior to the operation before the induction of anesthesia, second before cardiopulmonary bypass, third after CPB, fourth 4 h postoperatively at the ICU. Major finding in our study is that S100β levels were lower in propofol group when compared to desflurane anesthesia. And also immune reaction was less in patients exposed to desflurane anesthesia when compared to propofol anesthesia as indicated by lower plasma concentrations of IL-8 and IL-6. Propofol is more preferable in terms of S100β for anesthetic management for CABG.  相似文献   
17.
18.

Background

Endoscopic ampullectomy is established as a valuable treatment for adenomas of the Vaterian papilla. Few large series are available, however, let alone any with long-term follow-up. Moreover, multiple tangible issues remain. The aim of our study was to evaluate efficacy, safety, and outcome of endoscopic ampullectomy and compare it to existing literature

Methods

This is a single-center, retrospective study with a minimal follow-up of 3 years including 91 patients, including familial adenomatous polyposis (FAP) and non-FAP, who had an endoscopic ampullectomy between 2000 and 2008. Outcome parameters included ampulloma characteristics, biotical accuracy as well as safety, efficacy, recurrence rate, and survival after endoscopic ampullectomy.

Results

Endoscopic resection was successful in 71 patients (78 %). Histological review of the resected specimens revealed nonspecific changes (13.8 %), low or medium grade dysplasia (52.9 %), high grade dysplasia (21.8 %) and carcinoma (18.3 %). Bioptic accuracy was 38.3 %. Overall complications were observed in 23 patients (25.2 %): pancreatitis (15.4 %), hemorrhage (12.1 %) and cholangitis (4.9 %). Recurrence occurred in 18.3 %. Fourteen patients underwent pancreaticoduodenectomy. Survival after complete endoscopic ampullectomy was excellent for patients with low to moderate grade dysplasia and high grade dysplasia. Incomplete endoscopic resection of high grade dysplasia or invasive carcinoma was associated with unfavorable outcome when treated merely endoscopically.

Conclusions

Endoscopic ampullectomy is obligatory for assessment of the true histological nature of an ampulloma. Endoscopic resection is a safe and efficient procedure for adenomas with low to moderate dysplasia but also for high grade dysplastic lesions, provided that a complete endoscopic resection is achieved.  相似文献   
19.

Purpose

Our objective was to assess the accuracy of computed tomographic virtual cystoscopy (CTVC) in the detection of urinary bladder lesions.

Methods

Twenty-five patients were examined using CTVC. Bladder scanned using multislice CT at a slice thickness of 1 mm. The data were transferred to a workstation for interactive navigation using surface rendering. Findings obtained from CTVC were compared with results from conventional cystoscopy and with pathological findings.

Results

Thirty-eight lesions were identified. The smallest was 0.2 × 0.3 cm; the largest was 7 × 4.5 cm. Both CTVC and conventional cystoscopy were used. Conventional cystoscopy detected the same number of lesions that were detected by CTVC. On morphological examination, 26 of the lesions were polypoid, 7 were sessile and 5 were bladder wall-thickening. While one of the polypoid lesions was reported as an inverted papilloma, 2 of the 5 lesions that were identified as wall-thickening were malignant and 3 were benign. The sensitivity of using CTVC to identify neoplasias was 100%; the accuracy was 89%.

Conclusion

Although the definitive diagnosis of some suspected urinary bladder tumours is only possible with conventional cystoscopy and biopsy, CTVC is a minimally invasive technique which provides beneficial information about urinary bladder lesions.  相似文献   
20.
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