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   213779篇
  免费   3438篇
  国内免费   100篇
耳鼻咽喉   1582篇
儿科学   8058篇
妇产科学   4044篇
基础医学   21255篇
口腔科学   2002篇
临床医学   18761篇
内科学   37368篇
皮肤病学   1077篇
神经病学   20043篇
特种医学   9740篇
外国民族医学   1篇
外科学   32387篇
综合类   2685篇
一般理论   49篇
预防医学   23393篇
眼科学   3150篇
药学   11883篇
中国医学   667篇
肿瘤学   19172篇
  2023年   325篇
  2022年   460篇
  2021年   865篇
  2020年   612篇
  2019年   972篇
  2018年   22880篇
  2017年   18056篇
  2016年   20229篇
  2015年   1836篇
  2014年   2117篇
  2013年   2840篇
  2012年   9931篇
  2011年   24084篇
  2010年   20378篇
  2009年   12997篇
  2008年   22123篇
  2007年   24337篇
  2006年   3254篇
  2005年   4803篇
  2004年   5808篇
  2003年   6500篇
  2002年   4565篇
  2001年   546篇
  2000年   655篇
  1999年   464篇
  1998年   648篇
  1997年   549篇
  1996年   354篇
  1995年   314篇
  1994年   320篇
  1993年   272篇
  1992年   185篇
  1991年   215篇
  1990年   250篇
  1989年   206篇
  1988年   180篇
  1987年   146篇
  1986年   138篇
  1985年   147篇
  1984年   140篇
  1983年   119篇
  1982年   123篇
  1981年   110篇
  1980年   117篇
  1979年   75篇
  1978年   75篇
  1977年   73篇
  1975年   68篇
  1974年   69篇
  1938年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Background There has been a trend toward minimally invasive treatment of early gastric cancer. We report the preliminary results of laparoscopy-assisted distal gastrectomy with laparoscopic sentinel lymph node biopsy after endoscopic mucosal resection. Methods Six patients underwent laparoscopy-assisted distal gastrectomy after endoscopic mucosal resection between February 2002 and October 2005 at Mie University Hospital. These patients first underwent laparoscopic sentinel lymph node biopsy and then laparoscopy-assisted distal gastrectomy with lymphadenectomy. Results No patient underwent conversion to open surgery during the operation. None of the patients had any postoperative complications. The mean length of postoperative hospital stay was 11.3 days. Sentinel lymph nodes were identified laparoscopically in five patients. There were 20 sentinel and 85 nonsentinel lymph nodes in the six patients. Postoperatively, tissue sections showed that none of the lymph nodes were metastasized. Immunohistochemistry with D2-40 antibody showed that there were normal lymphatics in the submucosal layer with mucosal defects at the endoscopic mucosal resection site. No patients had any tumor recurrence during followup. Conclusions Laparoscopy-assisted distal gastrectomy after endoscopic mucosal resection was a safe and curative procedure. Endoscopic mucosal resection before sentinel lymph node biopsy was acceptable for early gastric cancer.  相似文献   
992.
We examined the clinical and radiographic results of 93 patients affected by knee arthritis or osteonecrosis subjected to unilateral cementless mobile-bearing total knee arthroplasty with the LCS prothesis (Depuy/Johnson & Johnson). The mean follow-up was 9.5 years (range, 7–12 years). Clinical evaluation was performed using the Knee Society rating system, while radiographic evaluation was done according to the Knee Society roentgenographic system. At the latest follow-up, the mean knee score was 87 points: the functional score improved from 40 to 90. Radiolucent lines were small and not progressive. The implant survival at 12 years was 88%. Six knees (7%) required revision for implant-related problems. We conclude that the mobile-bearing prosthesis is a successful device even at long-term follow-up.  相似文献   
993.
Skin is the most commonly used tissue for the transplantation. A meticulous care of the donor site is needed to prevent scarring, delayed healing, and pain. Various agents and dressing materials have been reported to help healing of skin graft donor sites. Sucralfate is an extensively used agent, which provides acute gastroprotection and acceleration of chronic ulcer healing. In this study, we assessed the effects of topical sucralfate on the healing of the split thickness skin graft donor sites in a prospective comparative way. The study was carried out on 32 randomly chosen patients undergoing surgery for various causes and requiring split thickness skin graft resurfacing. The upper halves of the skin graft donor sites on the thighs were simply covered with paraffin gauze and the lower half was covered with sucralfate-soaked paraffin gauzes. The day of full epithelization varied from 6 to 9 days and 8–12 days on the sucralfate-applied areas and on the control sites, respectively. The mean value of the healing was 7.01 days in the studied lower halves and 10.8 days in the upper halves. The healing rate was strikingly faster and less painful on the sucralfate-applied areas. We were able to discharge patients earlier than usual, and patients’ comfort increased. It seems that sucralfate is a promising topical agent to increase the healing rate and decrease the incidence of associated problems such as pain and hypertrophic scar.  相似文献   
994.
Purpose A Candida infection of the pancreas, which previously was considered extremely unusual, has been increasingly reported in recent years. The present study was conducted with the aim of performing a cohort analysis of our patients with acute pancreatitis to find out the incidence, sites, and species of Candida involvement; and to evaluate the risk factors, severity, and course of illness of such patients. Methods A total of 335 patients with acute pancreatitis were investigated for a possible Candida infection of the pancreas from January 2000 to May 2003. The clinical records of all those patients who were positive for Candida spp. isolation from pancreatic tissue were analyzed. The clinical records of 32 more cases, randomly selected from the patients who were investigated for candidal pancreatitis but were negative for Candida spp., were also analyzed in order to compare their findings with those patients with a true Candida infection of the pancreas. Results A true or possible Candida infection was observed in 41 (12.2%) of those 335 patients and Candida tropicalis was the most common isolate (43.9%). Candida spp. were isolated from pancreatic necrotic tissue in 22 (6.6%) patients (true infection). A possible Candida infection (positive drain fluid effluents at least twice, without any Candida isolation from pre/per operative samples from pancreas) was seen in 19 (5.7%) patients. Candida was also isolated exclusively from the blood in another 19 patients with a clinical diagnosis of acute pancreatitis. A risk factor analysis showed that patients with severe injury to the pancreas, on prophylactic fluconazole, and after surgical intervention were significantly more prone to develop a Candida infection. Patients with a Candida superinfection also had a significantly increased hospital stay and higher mortality. Conclusion This study thus emphasizes the important role of Candida infection in patients with acute pancreatitis and demonstrates the need for early attention.  相似文献   
995.
A closing wedge osteotomy of the lumbar spine may be considered to correct posture and spinal balance in progressive thoracolumbar kyphotic deformity caused by ankylosing spondylitis (AS). Adequate deformity planning is essential for reliable prediction of the effect of surgical correction of the spine on the sagittal balance and horizontal gaze of the patient. The effect of a spinal osteotomy on the horizontal gaze is equal to the osteotomy angle. However, the effect of a spinal osteotomy on the sagittal balance depends on both the correction angle and the level of osteotomy simultaneously. The relation between the correction angle, the level of osteotomy and the sagittal balance of the spine can be expressed by a mathematical equation. However, this mathematical equation is not easily used in daily practice. We present the computer program ASKyphoplan that analyses and visualizes the planning procedure for sagittal plane corrective osteotomies of the spine in AS. The relationship between the planned correction angle, level of osteotomy and sagittal balance are coupled into the program. The steps taken during an ASKyphoplan run are outlined, and the clinical application is discussed. The application of the program is illustrated by the analysis of the data from a patient recently treated by a lumbar osteotomy in AS. The software can be used free of charge on the internet at under the heading “research” in the menu.  相似文献   
996.
Gastrojejunostomy stricture after Roux-en-Y gastric bypass occurs in 3 to 27% of morbidly obese patients in the USA. We questioned whether preoperative patient characteristics, including demographic attributes and comorbid disease, might be significant factors in the etiology of stricture. In this study from November 2001 to February 2006 (51 months), at a high-volume bariatric center, of the 1,351 patients who underwent laparoscopic gastric bypass, 92 developed stricture (6.8%). All but two were treated successfully by endoscopic dilation. All patients stopped nonsteroidal anti-inflammatory medications 2 weeks prior to surgery and did not restart them. The operative procedure included the use of a 21-mm transoral circular stapler to create the gastrojejunostomy; the Roux limb was brought retrogastric, retrocolic. In an effort to reduce our center’s stricture rate, late in the study, U-clips used at the gastrojejunostomy were replaced by absorbable sutures, and postoperative H2 antagonists were added to the treatment protocol. The change to absorbable polyglactin suture proved to be significant, resulting in a lower stricture rate. The addition of H2 antagonists showed no significant effect. Following the retrospective review of the prospective database, univariate and multivariate logistic regression analyses identified factors associated with the development of stricture. Gastroesophageal reflux disease and age were each shown to be statistically significant independent predictors of stricture following laparoscopic gastric bypass. Presented at the 2006 Annual Meeting of the Society for Surgery of the Alimentary Tract, May 20–24, Los Angeles, CA (poster presentation).  相似文献   
997.
This article analyses the incidence of facet joint violation by pedicle screws inserted via the two most commonly used techniques, intersection and mammillary. Pedicle screws were inserted on each side of fresh-frozen human cadevaric specimen lumbosacral spines using the two techniques. All facet joints which were violated were found to be on the right side, where the mamillary process technique was employed. The incidence of facet joint violation was higher in the mammillary technique, which was statistically significant. The intersection technique appears to be safer than the mamillary with respect to violation of the adjacent superior facet joint.  相似文献   
998.
Aim To review our long-term results of the sub-ureteric injection of calcium hydroxyapatite in the endoscopic management of vesicoureteral reflux (VUR) in children. Materials and methods A sub-ureteric injection of calcium hydroxyapatite was given to 14 children (23 ureteral units) affected by VUR grades I–V. All children were followed-up with monthly urine cultures, and a renal ultrasound was done on the postoperative 4th week, while the first voiding cysto-urethrogram (VCUG) control was performed on postoperative week 12. The children were followed-up with yearly renal ultrasound and monthly urine cultures, thereafter. Data from the patients’ charts were retrospectively analyzed regarding the outcome of the procedures. Results Mean follow-up time was 52 months (47–60 months). VUR was cured in 47.4% of cases after a single injection. After the second injection the global success rate was 52.1%. Ureteroneocystostomy was performed on seven refluxing ureters of five children unresponsive to sub-ureteric injection therapy. One patient underwent nephroureterectomy because of a non-functioning kidney secondary to ureteral obstruction due to migration of material at the 23rd month postoperatively. Conclusion Although favorable short-term success rates have been reported with the sub-ureteric injection of calcium hydroxyapatite without any side effects, our long-term results showed a low success rate, with the only reported serious morbidity.  相似文献   
999.
Background The future remnant liver (FRL) limit for safe major hepatectomy with low risk of postoperative liver failure has not yet been well defined. Methods Between April 2000 and September 2004, every patient scheduled for major hepatectomy in our institution underwent CT-volumetry of FRL. Patients with FRL <25% underwent portal vein embolization (PVE). Exclusion criteria were PVE, associated vascular resection and liver cirrhosis. The FRL was correlated with short-term results in patients with normal liver (group A) and those with impaired liver function secondary to neoadjuvant chemotherapy or cholestasis (bilirubin >2 mg/100 ml) (group B). Liver dysfunction was defined as both PT <50% and serum bilirubin level >5 mg/100 ml for three or more consecutive days. Results A total of 119 patients were analyzed, 72 in group A and 47 in group B. The FRL value was the only significant risk factor for postoperative liver dysfunction in the univariate and multivariate analysis (p = 0.009). The FRL did not correlate with postoperative mortality and morbidity. Bilirubin and prothrombin time (PT) on days 3 and 7 were significantly correlated to FRL in both groups. In group A, patients with postoperative liver dysfunction had a FRL<30% (3 versus 0; p = 0.005). According to receiving operator characteristic (ROC) curve analysis, a FRL value of 26.5% predicted postoperative liver dysfunction with 66.7% sensitivity, 97.1% specificity, 50% positive predictive value (PPV), and 98.5% negative predictive value (NPV). In group B, patients with postoperative liver dysfunction had a FRL <35% (4 versus 0; p = 0.027). According to ROC curve analysis, a FRL value of 31.05% predicted postoperative liver dysfunction with 75% sensitivity, 79.1% specificity, 25% PPV, and 97.1% NPV. Conclusions Hepatectomy can be considered safe when FRL is >26.5% in patients with healthy liver and >31% in patients with impaired liver function.  相似文献   
1000.
Rabbits are the experimental animals of choice in many studies including flaps, wounds, and topical trials for new pharmacological agents. Because the topical drugs and other materials used for dressing are irritating to the animal, they tend to remove dressings, bandages, drapes, insensate flaps, and also topical drugs by scratching, licking, and biting if they are within the reach of the animal. In this study, we report an easy to prepare, user-friendly, comfortable, and cheap dressing protector called a dressing shield to prevent these problems.  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