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   382802篇
  免费   24361篇
  国内免费   2832篇
耳鼻咽喉   5206篇
儿科学   8267篇
妇产科学   10097篇
基础医学   53592篇
口腔科学   11869篇
临床医学   30385篇
内科学   79317篇
皮肤病学   8696篇
神经病学   27426篇
特种医学   14056篇
外国民族医学   82篇
外科学   61135篇
综合类   9997篇
现状与发展   1篇
一般理论   64篇
预防医学   17605篇
眼科学   9474篇
药学   31236篇
  1篇
中国医学   2197篇
肿瘤学   29292篇
  2021年   2706篇
  2019年   2779篇
  2018年   4590篇
  2017年   3507篇
  2016年   3606篇
  2015年   4111篇
  2014年   5805篇
  2013年   7512篇
  2012年   10225篇
  2011年   10434篇
  2010年   6324篇
  2009年   5970篇
  2008年   9654篇
  2007年   10519篇
  2006年   10429篇
  2005年   9463篇
  2004年   8995篇
  2003年   8697篇
  2002年   8372篇
  2001年   28324篇
  2000年   28860篇
  1999年   23756篇
  1998年   5202篇
  1997年   4273篇
  1996年   3860篇
  1995年   3499篇
  1994年   3125篇
  1993年   2852篇
  1992年   16113篇
  1991年   14867篇
  1990年   14207篇
  1989年   14002篇
  1988年   12612篇
  1987年   12088篇
  1986年   11121篇
  1985年   10336篇
  1984年   6925篇
  1983年   5617篇
  1982年   2729篇
  1979年   5502篇
  1978年   3359篇
  1977年   2981篇
  1975年   2652篇
  1974年   3075篇
  1973年   2883篇
  1972年   2851篇
  1971年   2792篇
  1970年   2532篇
  1969年   2561篇
  1968年   2262篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Kent bundle interruption for ventricular preexcitation has been successfully accomplished utilizing several different surgical techniques. The external closed-heart technique of Guiraudon combining surgical dissection and cryoablation has been used to interrupt 52 accessory pathways in 47 consecutive patients since May, 1985. The 35 male and 12 female patients ranged in age from 10 to 67 years (mean, 30 years). There were 25 left free wall, 13 right free wall, 13 posterior septal, and 1 anterior septal accessory pathways. Preoperative and intraoperative electrophysiological studies were performed in all patients to induce the arrhythmia and localize all accessory pathways. The operation consisted of dissection of the atrioventricular fat pad. Following this, the delta wave and retrograde accessory pathway conduction disappeared, thereby indicating successful pathway ablation. In 4 patients with right-sided accessory pathways, interruption of the pathway required cryoablation. Cryolesions (made with cryoprobe at -60 degrees C for two minutes) were created in the region of the accessory pathway insertion. All accessory pathways were successfully ablated without any deaths or heart block. Concomitant surgical procedures were performed in 4 patients. Two patients required a second operation the next day for an accessory pathway not found at the initial operation. Three patients had postpericardiotomy syndrome, and 4 had recurrent atrial fibrillation requiring therapy. The remaining patients have had no arrhythmia recurrence and have remained drug free after a follow-up of 1 month to 22 months (mean, 12.5 months). We conclude that the closed-heart technique of accessory pathway ablation is safe and reproducible, obviates the necessity for aortic cross-clamping and cardioplegic arrest, and allows instantaneous monitoring of conduction over the pathway.  相似文献   
992.
993.
994.
Serum myoglobin levels have been found to be elevated for a few hours after removal of a tourniquet. In the present study, levels of serum myoglobin were measured by radioimmunoassay from local blood samples in patients who were treated with surgery of the hand in a bloodless field. After removal of the tourniquet blood samples were obtained from the antecubital vein of each patient immediately after release, five minutes, one hour, and 24 hours later. In these samples the serum myoglobin levels were not influenced by the mode of anesthesia, tourniquet time, or specific type of surgery. When the upper extremity was cooled with ice water before application of the tourniquet, however, the increase of serum myoglobin was statistically significantly inhibited when compared with the normothermic condition. Muscle injury due to tourniquet ischemia may be decreased by cooling of the upper extremity prior to tourniquet application.  相似文献   
995.
In situ hybridization of prostate-specific antigen mRNA in human prostate.   总被引:4,自引:0,他引:4  
Prostate-specific antigen (PSA) mRNA was detected by in situ hybridization utilizing a 428 base pair [35S]-labelled cDNA probe from the 3' noncoding region of the PSA gene. Thirty six fresh surgical specimens were collected from patients undergoing radical retropubic prostatectomy for carcinoma of the prostate. Quantitative analysis of the levels of PSA mRNA in both the benign and malignant tissues was performed using an IBAS 2000 Image Analysis System. The results of this study demonstrated that there is a significant decrease in the expression of PSA mRNA in the carcinoma tissue when compared to the benign epithelium. The average binding (number of silver grains/1 x 10(4) microns. 2) for 20 specimens of malignant epithelium was 475 +/- 161 and 586 +/- 140 for 16 specimens of benign epithelium (p less than 0.05). Eleven patients had both benign and malignant tissue from the same surgical specimen available for study. From these paired specimens, the PSA mRNA expression was also significantly reduced in the malignant epithelium when compared to the benign epithelium, 445 +/- 162 and 588 +/- 135 respectively (p less than 0.005). The PSA protein was detected using a monoclonal antibody to PSA with an immunohistochemical staining technique. The PSA protein expression paralleled the expression of the PSA mRNA in the majority of the tissue sections. Many of the tumor specimens showed a heterogeneous expression of PSA, whereas all of the benign epithelium had a uniform high level of PSA expression. In conclusion, PSA mRNA and protein are located only within the glandular epithelial tissue, the expression of PSA protein parallels that of the PSA mRNA, and both the PSA protein and PSA mRNA are significantly decreased in the malignant epithelium when compared to benign prostatic epithelium.  相似文献   
996.
A 48-year-old woman was admitted to our hospital suffering from chest and back pain. The aortogram and CT scanning revealed aortic dissection (DeBakey II type). Six days after onset, the emergent operation was carried out under the cardio-pulmonary bypass. Myocardial protection was made by retrograde coronary sinus perfusion (RCSP) with cold GIK. The ascending aorta was replaced with an artificial graft including the entry. Massive bleeding in the pericardial space and the rupture of coronary sinus was recognized immediately after declamping of the aorta. Repair was made successfully under induced electric ventricular fibrillation. Care for RCSP was discussed.  相似文献   
997.
Thymolipoma is a very rare mediastinal tumor. We reported a case of 52-year-old female with thymolipoma which was located in the cervicomediastinal area. The chest X-ray film revealed an abnormal shadow in the superior mediastinum. Computed Tomography (CT) clearly showed the existence of a large mass in the left side of the trachea. The angiogram showed that there was a stenosis on the left brachiocephalic vein. On June 13, 1988, median sternotomy was performed. A large tumor, about 5.5 x 13 x 5.5 cm, was found arising from the left cervical area. This tumor was excised completely and thymolipoma was diagnosed histopathologically. The post-operative course was very satisfactory.  相似文献   
998.
Transurethral resection of urinary bladder tumor was performed under spinal anesthesia which has been considered to be rather contraindicated in a patient with idiopathic hypertrophic cardiomyopathy. Caution was exercised not to compromise myocardial oxygen supply demand ratio. Central venous pressure (CVP) was continuously monitored and crystalloid solution was infused to maintain CVP in pre-anesthetic level, thereby preventing the reduction in arterial pressure. The patient was hemodynamically stable throughout the operation. This case indicates that if adequate preload could be preserved and hypotension avoided, spinal anesthesia may not be precluded in patients with idiopathic hypertrophic cardiomyopathy.  相似文献   
999.
1000.
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