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   907篇
  免费   119篇
  国内免费   13篇
耳鼻咽喉   20篇
儿科学   24篇
妇产科学   15篇
基础医学   164篇
口腔科学   43篇
临床医学   90篇
内科学   157篇
皮肤病学   20篇
神经病学   67篇
特种医学   129篇
外科学   97篇
综合类   13篇
预防医学   89篇
眼科学   5篇
药学   42篇
肿瘤学   64篇
  2022年   6篇
  2021年   12篇
  2019年   8篇
  2018年   20篇
  2017年   8篇
  2016年   15篇
  2015年   19篇
  2014年   17篇
  2013年   34篇
  2012年   37篇
  2011年   34篇
  2010年   31篇
  2009年   42篇
  2008年   29篇
  2007年   48篇
  2006年   35篇
  2005年   25篇
  2004年   28篇
  2003年   16篇
  2002年   22篇
  2001年   22篇
  2000年   12篇
  1999年   25篇
  1998年   61篇
  1997年   52篇
  1996年   35篇
  1995年   26篇
  1994年   24篇
  1993年   16篇
  1992年   8篇
  1991年   17篇
  1990年   22篇
  1989年   25篇
  1988年   27篇
  1987年   23篇
  1986年   17篇
  1985年   18篇
  1984年   13篇
  1983年   10篇
  1982年   8篇
  1981年   6篇
  1980年   9篇
  1979年   6篇
  1978年   6篇
  1977年   10篇
  1975年   9篇
  1974年   7篇
  1973年   5篇
  1968年   6篇
  1967年   4篇
排序方式: 共有1039条查询结果,搜索用时 14 毫秒
81.

Background  

Potassium disorders can cause major complications and must be avoided in critically ill patients. Regulation of potassium in the intensive care unit (ICU) requires potassium administration with frequent blood potassium measurements and subsequent adjustments of the amount of potassium administrated. The use of a potassium replacement protocol can improve potassium regulation. For safety and efficiency, computerized protocols appear to be superior over paper protocols. The aim of this study was to evaluate if a computerized potassium regulation protocol in the ICU improved potassium regulation.  相似文献   
82.
Insertion of a screw biopsy stylet into a thin-walled biopsy needle greatly enhances detection of the needle during ultrasound-guided percutaneous biopsy. This technique is helpful when precise needle-tip localization is needed for biopsies of small lesions.  相似文献   
83.
The mode of action of the Kensey catheter, a new atheroablation device, was investigated. Fresh above-the-knee amputated legs were used for recanalization of the superficial femoral artery. The variables used were identical to those of clinical trials, including a rotational speed of 50,000 rpm and an injection rate of 40 mL/min. The debris produced by the catheter was studied cytologically, and the arterial segments were examined histologically. The particle size in the debris ranged from 1 to 2,000 microns. The softer plaques produced a fine fibrin dust background with long strips of intima ranging from 10 to 2,000 microns. Complicated calcified plaques produced larger background material (10-120 microns) but smaller strips of intima (50-800 microns). Dissections and perforations occurred. Some of the debris produced by the atheroablation process was used to embolize a canine heart and kidney. Small focal infarctions were found in the heart, and large and multiple infarcts were seen in the kidney. In clinical studies the debris appears to be tolerated in the lower extremities. Its safety in the kidney and heart are questioned.  相似文献   
84.
Cloning of urease gene sequences from Providencia stuartii.   总被引:24,自引:7,他引:17       下载免费PDF全文
Providencia stuartii was the most prevalent isolate recovered from urine specimens taken weekly over a 1-year period from 51 nursing home patients with urinary catheters in place. Thirty percent of the isolates were urease positive. Urease, which is implicated in renal stone formation, was shown to be transmissible on an 82-kilobase conjugative plasmid in one isolate. Plasmid DNA isolated from this strain was digested with EcoRI, ligated into the EcoRI site of pBR322, and used to transform Escherichia coli HB101. Ampicillin-resistant clones were replica plated onto urea segregation agar, and a urease-positive clone, designated pMID101, was isolated. Recombinant and native urease from cell lysates had identical electrophoretic mobilities on nondenaturing polyacrylamide urease activity gels. The native enzyme was induced fourfold when cells were grown in the presence of 0.1% urea and had a km of 9.4 mM and a Vmax of 3.2 mumol of NH3 per min per mg of protein. Its molecular weight was estimated to be 375,000 +/- 35,000 by Sephacryl S-300 chromatography. The enzyme was cytoplasmic in P. stuartii, was inhibited in vitro by hydroxyurea, acetohydroxamic acid, and EDTA, and appears to have a complex subunit structure and a unique molecular size within genera of the Proteeae tribe.  相似文献   
85.
K.A. Mobley  FFARCS    J.G. Wandless  FFARCS    D. Fell  FFARCS    A. McBurney  PhD 《Anaesthesia》1991,46(6):500-501
Serum bupivacaine concentrations were measured in 12 children who underwent elective herniotomy and who received analgesia in the form of wound infiltration. Mean (SD) peak concentration was 0.36 (0.14) micrograms/ml and time to peak concentration was 14.6 (7.2) minutes after infiltration of 1.25 mg/kg of bupivacaine. These concentrations are lower than those associated with other local anaesthetic blocks and well below potentially toxic levels. Wound infiltration provides a simple, effective and safe method of providing postoperative analgesia for hernia repair in children.  相似文献   
86.
Garel  LA; Belli  D; Grignon  A; Roy  CC 《Radiology》1987,165(3):639-641
Percutaneous cholecystography was performed on 13 children who had biliary system abnormalities: two had biliary hypoplasia, five had sclerosing cholangitis, three had cirrhosis, two had distal choledochal obstruction, and one had an obstructed portoenterostomy. In 12 patients transcholecystic cholangiography showed, without significant complications, the intra-and extrahepatic bile ducts. In one patient with primary sclerosing cholangitis, the intrahepatic bile ducts were not opacified satisfactorily; dilatation of the gallbladder required surgical drainage. The transcholecystic technique is indicated when the intrahepatic bile ducts are either mildly dilated or not dilated.  相似文献   
87.
Although there is no consensus on its incidence, bilateral peritonsillar abscess is an unusual variant of an otherwise relatively common otolaryngologic disease. A bilateral peritonsillar abscess can be differentiated from other oropharyngeal pathology with a detailed physical examination and complementary imaging. Its diagnosis should always be considered in patients who have signs and symptoms that are suggestive of peritonsillar abscess but whose intraoral examination yields atypical findings, as well as in patients with marked distress or trismus. This article describes the case of a young man who came to the emergency room with bilateral peritonsillar abscess. The author believes that this report contains the only published photograph of the intraoral appearance of this condition.  相似文献   
88.
The neuronal ceroid lipofuscinoses (NCL) are progressive neurodegenerative disorders with onset from infancy to adulthood that are manifested by blindness, seizures, and dementia. In NCL, lysosomes accumulate autofluorescent proteolipid in the brain and other tissues. The mnd/mnd mutant mouse was first characterized as exhibiting adult-onset upper and lower motor neuron degeneration, but closer examination revealed early, widespread pathology similar to that seen in NCL. We used the autofluorescent properties of accumulated storage material to map which CNS neuronal populations in the mnd/mnd mouse show NCL-like pathological changes. Pronounced, early accumulation of autofluorescent lipopigment was found in subpopulations of GABAergic neurons, including interneurons in the cortex and hippocampus. Staining for phenotypic markers normally present in these neurons revealed progressive loss of staining in the cortex and hippocampus of mnd/mnd mice, with pronounced hypertrophy of remaining detectable interneurons. In contrast, even in aged mutant mice, many hippocampal interneurons retained staining for glutamic acid decarboxylase. Treatment with insulin-like growth factor-1 partially restored interneuronal number and reduced hypertrophy in some subregions. These results provide the first evidence for the involvement of interneurons in a mouse model of NCL. Moreover, our findings suggest that at least some populations of these neurons persist in a growth factor-responsive state.  相似文献   
89.
90.
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