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   2501篇
  免费   150篇
  国内免费   30篇
耳鼻咽喉   3篇
儿科学   32篇
妇产科学   46篇
基础医学   287篇
口腔科学   38篇
临床医学   185篇
内科学   824篇
皮肤病学   66篇
神经病学   190篇
特种医学   81篇
外科学   472篇
综合类   14篇
一般理论   1篇
预防医学   31篇
眼科学   35篇
药学   102篇
中国医学   6篇
肿瘤学   268篇
  2024年   4篇
  2023年   13篇
  2022年   38篇
  2021年   65篇
  2020年   32篇
  2019年   32篇
  2018年   57篇
  2017年   49篇
  2016年   65篇
  2015年   74篇
  2014年   106篇
  2013年   99篇
  2012年   180篇
  2011年   173篇
  2010年   89篇
  2009年   88篇
  2008年   140篇
  2007年   149篇
  2006年   166篇
  2005年   170篇
  2004年   159篇
  2003年   132篇
  2002年   139篇
  2001年   29篇
  2000年   17篇
  1999年   34篇
  1998年   44篇
  1997年   25篇
  1996年   38篇
  1995年   47篇
  1994年   38篇
  1993年   16篇
  1992年   10篇
  1991年   8篇
  1990年   6篇
  1989年   4篇
  1986年   5篇
  1983年   8篇
  1982年   3篇
  1981年   5篇
  1980年   3篇
  1978年   5篇
  1976年   4篇
  1975年   2篇
  1959年   5篇
  1958年   13篇
  1957年   17篇
  1956年   24篇
  1955年   17篇
  1954年   15篇
排序方式: 共有2681条查询结果,搜索用时 0 毫秒
1.
2.
We report a case of a patient in whom endoscopic band ligation was achieved for postpolypectomy gastric bleeding. A 76‐year‐old man visited our hospital because of anemia. Endoscopy revealed a gastric polyp, approximately 12 mm in diameter, on the lesser curvature in the distal gastric body. The polyp was considered to be the source of chronic anemia and was therefore removed by using standard careful snare‐cautery polypectomy technique. Four days later, follow‐up endoscopy was performed to evaluate the postpolypectomy site, and an active bleeding postpolypectomy ulcer was identified. Initial attempts to achieve hemostasis with ethanol injection were unsuccessful. Immediate hemostasis was obtained with a subsequent endoscopic band ligation device. There has been no recurrent bleeding. Endoscopic band ligation might be a good treatment modality for the treatment of a postpolypectomy gastric bleeding lesion.  相似文献   
3.
A 73-year-old male with a history of diabetes mellitus was admitted to our hospital for acute renal failure. An ultrasonogram revealed bilateral hydronephrosis, which worsened despite insertion of a bladder catheter. Nephrostomy catheters were positioned bilaterally, and Candida albicans was found in the urine culture. The patient was successfully treated with intermittent direct irrigation and i.v. antifungal agent therapy. Since 1977, approximately 50 cases of fungus balls or fungal bezoars in the urinary tract have been reported, but the majority of these cases have been characterized by unilateral ureteral or bladder involvement. Herein, we report a case of acute renal failure as a result of bilateral ureteral obstruction by Candida albicans fungus balls.  相似文献   
4.
5.
Uptake of dehydroascorbic acid (DHA) was studied in two types of dog erythrocytes with high GSH and normal GSH levels. Compared with ascorbic acid uptake, DHA produced a much greater ascorbic acid accumulation in dog erythrocytes. Both dog erythrocytes showed a concentration dependence of DHA uptake, and cellular ascorbic acid concentrations were significantly higher in high-GSH cells than in normal-GSH cells. Glucose and cytochalasin B inhibited DHA uptake. This suggests that DHA enters dog erythrocytes predominantly by the facilitated glucose transporter, particularly by the Glut 1 glucose transporter. The rate of glucose uptake was quite similar in the two types of cells. Compared with normal-GSH cells, high-GSH cells were more resistant to oxidative stress induced by high concentration of DHA. As a rapid entry of DHA inflicts on cells a heavy demand for GSH for its reduction to ascorbic acid, high-GSH cells containing a larger reserve of GSH have an advantage over normal-GSH cells in both ascorbic acid accumulation and resisting oxidative stress produced by DHA.  相似文献   
6.
Abstract: We analyzed the expression of CEA, CA19-9, CA125, CA15-3 (DF3), PCNA and p53 immunohistochemically in 14 tissue specimens of mucosal cancers in adenoma, seven tubulovillous adenoma specimens, and 16 tubular adenoma specimens. The rates of positive staining for mucosal cancer in adenoma, tubulovillous adenoma and tubular adenoma specimens, respectively, were: for CEA: 100%, 85.7% and 75%; for CA19-9: 71.4%, 71.4% and 56.2%; for CA125:0%, 0% and 0%;for CA15-3 (DF3): 64.3 %, 0% and 0 %; for PCNA: 100%, 88.9% and 56.2%; and for p53: 35.7%, 0% and 0% . The results suggest that the expressions of CEA, CA19-9, CA15-3 (DF3), PCNA and p53 are related to colorectal tumorigenesis. None of the specimens studied showed staining for CA125, suggesting that CA125 is not involved in the early stages of colorectal carcinogenesis. There was no significant difference in the rates of positive staining for CEA and CA19-9 among mucosal cancer in adenoma, tubular adenoma and tubulovillous adenoma specimens. However, the rates of positive staining for PCNA and p53 were significantly higher in mucosal cancer in adenoma specimens than for tubular adenoma specimens (p<0.05), and the rate of CA15-3 (DF3) positive staining was significantly higher for mucosal cancer in adenoma than for tubulovillous adenoma (p<0.01) and tubular adenoma (p< 0.001) specimens. Therefore, the CA15-3 (DF3) antigen is an immunohistochemical marker for colorectal carcinomas. The present results suggest that CA15-3 (DF3), PCNA and p53 play important roles in the genesis of colorectal adenomas.  相似文献   
7.
Antiandrogen withdrawal syndrome (AWS) is a well-established phenomenon in prostate cancer. However, responses to AWS are usually of limited duration, and a complete response (CR) is extremely rare. We present two patients who exhibited a chemical CR for more than 2 years after the discontinuation of steroidal antiandrogen chlormadinone acetate use. Whether patients who respond to antiandrogen withdrawal include a group of patients with a better prognosis remains uncertain. However, considering that the usual survival period of patients with hormone-resistant prostate cancer is approximately 12 months, both of the patients reported here, who are present in excellent physical condition, exhibiting an improved quality of life, and attending their hospital as outpatients, obviously acquired a prolonged survival because of AWS.  相似文献   
8.
Background: Endoscopic mucosal resection (EMR) is widely accepted as a minimally invasive treatment for early gastric cancer (EGC) in Japan. However, the criteria for EMR must be strictly adhered to otherwise patients will miss the chance for additional therapy. We assess the important factor in expanding the indication of EMR. Methods: We investigated 1101 EGCs that had been resected by EMR at the National Cancer Center Hospital (NCCH), Tokyo, Japan, according to the indication recommended by Japanese Gastric Cancer Association (JGCA) and the expanded indication proposed by NCCH. Curability and local recurrence of the EMRs were assessed related to the applied indication and the number of resected specimens. Results: The recurrence rate of non‐evaluable resection was higher than that of evaluable resection (P < 0.0001). Eighty‐three lesions among 772 lesions in the JGCA group were non‐evaluable. Thirty‐seven leisons among 329 lesions in the NCCH group were non‐evaluable. There was no difference in the rate of non‐evaluable resection between JGCA and NCCH groups (P = 0.8329). However, the rate of curative resection was lower in the NCCH group than in the JGCA group (P = 0.0009). In piecemeal resection, there was no difference in the rate of non‐evaluable resection between JGCA and NCCH groups (P = 0.0527). In one‐piece resection, the rate of non‐evaluable resection was lower in the NCCH group than the JGCA group (P = 0.0137). Conclusion: Based on our series of cases, we propose one‐piece resection as a gold standard for EMR because it enables accurate histological evaluation, even in the EMR, according to the expanded indication.  相似文献   
9.
10.
Objective: Reoperative coronary bypass grafting is at high risk. Particularly in redo cases where the patent graft is running near the midline of the sternum, the graft may be exposed to injury by a median sternotomy and subsequent dissection. Whereas, off-pump bypass grafting from the left axillary artery or descending thoracic artery by a left thoracotomy approach is safe for preventing graft damage.Methods: From March 1998 to February 2002, we performed off-pump coronary artery bypass grafting by a left thoracotomy approach in 9 patients. The left axillary artery was used as the inflow vessel in 4 cases, and the descending thoracic, aorta in 5.Results: The radial artery was anastomosed proximally to the axillary artery in 4 cases and the descending thoracic aorta in one case. The saphenous vein graft was anastomosed, proximally to the descending thoracic aorta in 4 cases. Transdiaphragmatic minimally invasive bypass grafting for the right coronary artery was simultaneously performed in 3 cases. Postoperative cardiac events were ventricular arrhythmia in 6 cases and supraventricular arrhythmia in 3 cases. There was no damage to the patent grafts. Postoperative coronary angiography performed, in 8 cases revealed all the grafts to be patent without stenosis. Cardiac symptoms were not found after the operation in any of the cases.Conclusions: These procedures can prevent the injury to patent grafts caused by a median sternotomy, and will be one of the useful strategies for reoperative off-pump coronary artery bypass grafting.  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