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   997403篇
  免费   75232篇
  国内免费   2616篇
耳鼻咽喉   12961篇
儿科学   34464篇
妇产科学   28461篇
基础医学   145278篇
口腔科学   27714篇
临床医学   90265篇
内科学   193544篇
皮肤病学   22912篇
神经病学   79106篇
特种医学   38385篇
外国民族医学   305篇
外科学   149484篇
综合类   23738篇
一般理论   385篇
预防医学   77819篇
眼科学   22606篇
药学   71861篇
  3篇
中国医学   2030篇
肿瘤学   53930篇
  2018年   10555篇
  2017年   8235篇
  2016年   9373篇
  2015年   10594篇
  2014年   14416篇
  2013年   22001篇
  2012年   28981篇
  2011年   30825篇
  2010年   18487篇
  2009年   17436篇
  2008年   28788篇
  2007年   30460篇
  2006年   30959篇
  2005年   29638篇
  2004年   28925篇
  2003年   27796篇
  2002年   26812篇
  2001年   46924篇
  2000年   48033篇
  1999年   40262篇
  1998年   11177篇
  1997年   10095篇
  1996年   10160篇
  1995年   9775篇
  1994年   9090篇
  1993年   8480篇
  1992年   32249篇
  1991年   31458篇
  1990年   31006篇
  1989年   29874篇
  1988年   27167篇
  1987年   27325篇
  1986年   25434篇
  1985年   24601篇
  1984年   18398篇
  1983年   15515篇
  1982年   9288篇
  1981年   8375篇
  1979年   16859篇
  1978年   12217篇
  1977年   10314篇
  1976年   9754篇
  1975年   10178篇
  1974年   12317篇
  1973年   11843篇
  1972年   10884篇
  1971年   10113篇
  1970年   9375篇
  1969年   8724篇
  1968年   8104篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Critically ill patients often demonstrate that whole body oxygen consumption (VO2) is dependent on oxygen delivery (DO2). In this retrospective study, the relationship of VO2 to DO2 in patients with isolated head injury (HI, n = 18) was compared to that in patients with multiple trauma (MT, n = 60) without serious head injury. Mean pulmonary capillary wedge pressure, central venous pressure, arterial PCO2, cardiac index, and oxygen delivery were significantly lower in HI, but oxygen consumption was not different in the groups. In both groups, changes in DO2 (delta DO2) within each patient were significantly correlated with changes in VO2 (delta VO2) in that same patient. This relationship was not different between the HI patients, (delta VO2 = (0.20 +/- 0.02) delta DO2), and the MT patients (delta VO2 = (0.17 +/- 0.01) delta DO2). When these groups were further divided into those with high hematocrit (greater than 32%) and low hematocrit (less than 32%), HI patients with a low hematocrit demonstrated a steeper regression slope, with 26 +/- 3% of the DO2 change being reflected in the VO2 change. This was significantly greater than the slope in HI patients with high hematocrit (13 +/- 3%) and the MT patients at high (19 +/- 2%) or low (16 +/- 2%) hematocrits. These data show a correlation between changes in oxygen delivery and consumption that is similar in both head-injury patients and multiple trauma patients without serious head injury. This relationship was greatest in head-injured patients at low hematocrit. This relationship of VO2 and DO2 in both groups suggests an influence of neurohumoral factors rather than local tissue phenomena.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
993.
Fibrin glue (FG) was used to achieve hemostasis of 16 splenic injuries in 14 patients. The etiologies of injury included five gunshot wounds, two stab wounds, four iatrogenic injuries, and five patients with blunt splenic trauma. The intraoperative blood loss averaged 1.8 +/- 2.4 (SD) liters and patients were transfused 3 +/- 2 units of blood perioperatively. The amount of FG required to achieve splenic hemostasis averaged 11 +/- 8 ml and varied directly with the grade of injury. One patient with a splenic hilar vascular injury (Grade V) underwent splenectomy following failure to achieve complete hemostasis despite the use of 25 ml of FG. All other splenic injuries were successfully managed using less than 25 ml of FG. Postoperative computerized tomographic (CT) scanning, performed in ten patients, was negative for rebleeding or abscess formation. The overall splenic salvage rate was 86%. FG was effective in achieving hemostasis of both superficial and deep splenic injuries. Its use as an adjunct in trauma surgery should result in increased splenic salvage rates compared with that obtained using conventional surgical techniques.  相似文献   
994.
We report a case of renal cell carcinoma within a simple renal cyst in the lower pole of the right kidney. Excretory urography showed a mass and ultrasonography revealed multiple renal cysts with a solid component arising from the wall in 1. This finding also was visualized by computerized tomography. Analysis of the cystic fluid showed a high cholesterol level but negative cytological results. At operation a 7 mm. tumor arose from the wall of the cyst. Histopathological examination showed grade 3 renal cell carcinoma with an aneuploid deoxyribonucleic acid content.  相似文献   
995.
Most publications citing the effectiveness of renal extracorporeal shock wave lithotripsy have used plain abdominal radiography to assess residual calculi after treatment. We compared radiologist sensitivity and specificity in the detection of calculi on plain abdominal radiographs versus conventional film-screen and digital renal tomograms in extracorporeal shock wave lithotripsy patients. Of the patients 50 were imaged before and within 24 hours after lithotripsy. Six radiologists evaluated the resultant 300 studies for the presence and location of calculi. The mean sensitivity for digital tomograms was 83% for pre-lithotripsy and post-lithotripsy studies, which was significantly higher than for plain abdominal radiography and conventional tomography after lithotripsy. However, there were significantly more false positive stone diagnoses associated with digital tomogram interpretation. Signal detection analysis verified the over-all superiority of digital tomography for post-extracorporeal shock wave lithotripsy imaging. Calculus detection by conventional and digital tomography is superior to detection by plain abdominal radiography. However, because we did not perform delayed imaging, it is not possible to say what impact digital tomography might have on the management of extracorporeal shock wave lithotripsy patients.  相似文献   
996.
Continent appendix stoma: a modification of the Mainz pouch technique   总被引:7,自引:0,他引:7  
The submucosally embedded in situ appendix guarantees an ideal continence mechanism in patients with ileocecal urinary reservoirs. To date this modification of the Mainz pouch technique has been performed successfully in 13 patients. The appendicocutaneous stoma was placed at the lower right abdominal quadrant in 12 patients and into the umbilical funnel in 1. Urodynamic investigations of the submucosally embedded appendix showed a maximum closure pressure of more than 80 cm. water in pressure profiles. Only 1 case of stomal stenosis required reoperation.  相似文献   
997.
Nephron-sparing surgery for renal cell carcinoma with venous involvement   总被引:1,自引:0,他引:1  
A nephron-sparing operation recently has been shown to provide extended survival free of disease in selected patients with localized renal cell carcinoma, particularly for tumors of lower stage. To define better the role of conservative surgical treatment in more locally advanced renal cell carcinoma we reviewed 9 patients with venous tumor involvement in solitary functioning kidneys who underwent a nephron-sparing operation. Complete tumor resection with adequate preservation of renal function was accomplished in all cases. Of the 9 patients 5 had no evidence of disease 7 to 93 months (mean 33.2 months) postoperatively. The remaining 4 patients died of metastatic renal cell carcinoma 17 to 47 months (mean 35.5 months) postoperatively, 2 of whom had concomitant local recurrences in the renal remnant. Based on previously reported results of total nephrectomy for renal cell carcinoma with venous involvement and the morbidity associated with renal replacement therapy, we believe that a nephron-sparing operation is a viable option in the management of these patients.  相似文献   
998.
The authors analyse observations over 113 patients (1978-1988) with destructive pancreatitis; there were 54 males and 59 females, whose ages ranged from 18 to 85 years. Complex nonoperative treatment was effective only in 17 patients. Cholecystectomy, cholecystostomy or choledochotomy was performed in 7 patients after their condition had improved. Eighty-eight patients underwent operation in the acute period. Total lethality was 71.6%. In summarizing the results the authors came to the conclusion that operative interventions should be postponed in clinical practice. The optimal time for the operation is 6-9 days after the onset of the disease.  相似文献   
999.
1000.
The authors reports their experience of 5 cases of intra- and peri-aqueductal tumors. With the exception of 1 case, a subependymoma of the aqueduct discovered at autopsy in a 77 year old woman, the 4 other patients (2 females and 2 males) are relatively young (respectively 14, 23, 14 and 26) at the time when they presented with signs of chronically raised intracranial pressure due to a triventricular hydrocephalus. One patient presented with a partial Parinaud's sign, but the focal and long tract signs were conspicuously absent in the other patients. The diagnosis of a space occupying lesion in the tectum mesencephali or in the aqueduct could only be ascertained with the recent use of M.R.I. The radiological work-up of the cases suggest that theses lesions, presumably of glial origin, are very slowly growing tumors. Four patients have been treated for their symptomatic hydrocephalus, but no treatment of the tumor has been proposed, as the clinical state and the images remain remarkably stable. (Mean duration of follow up from the time of shunting = 3.7 years, extremes = 1.5-8 years). A review of the literature shows that not more than 48 cases of tumors of the aqueduct have been reported. Because of the small number of such observations, there are, until now, no precise informations on the management of such cases to decide if the patient will benefit of an open or stereotactic biopsy associated with radiotherapy or if one can rely on serial clinical and radiological examinations. Further information on the long term follow up is needed.  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