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   29927篇
  免费   1307篇
  国内免费   882篇
耳鼻咽喉   246篇
儿科学   509篇
妇产科学   124篇
基础医学   1390篇
口腔科学   195篇
临床医学   4345篇
内科学   10232篇
皮肤病学   44篇
神经病学   244篇
特种医学   2132篇
外科学   2235篇
综合类   5564篇
预防医学   1325篇
眼科学   133篇
药学   2309篇
  34篇
中国医学   947篇
肿瘤学   108篇
  2024年   21篇
  2023年   237篇
  2022年   647篇
  2021年   945篇
  2020年   803篇
  2019年   590篇
  2018年   688篇
  2017年   665篇
  2016年   734篇
  2015年   926篇
  2014年   2293篇
  2013年   2037篇
  2012年   2021篇
  2011年   2114篇
  2010年   1740篇
  2009年   1835篇
  2008年   1892篇
  2007年   1844篇
  2006年   1723篇
  2005年   1396篇
  2004年   1161篇
  2003年   944篇
  2002年   751篇
  2001年   652篇
  2000年   533篇
  1999年   401篇
  1998年   335篇
  1997年   308篇
  1996年   222篇
  1995年   216篇
  1994年   195篇
  1993年   136篇
  1992年   117篇
  1991年   138篇
  1990年   93篇
  1989年   90篇
  1988年   74篇
  1987年   85篇
  1986年   57篇
  1985年   67篇
  1984年   65篇
  1983年   40篇
  1982年   55篇
  1981年   37篇
  1980年   32篇
  1979年   29篇
  1978年   25篇
  1977年   30篇
  1975年   15篇
  1973年   12篇
排序方式: 共有10000条查询结果,搜索用时 71 毫秒
51.
Abstract: A prospective study was performed to determine whether low-density lipoprotein (LDL) apheresis, when performed only immediately before and after percutaneous transluminal coronary angioplasty (PTCA), is effective in preventing restenosis of coronary artery lesions following PTCA. Thirty-six patients with coronary heart disease (CHD) and hypercholesterolemia were divided into 2 groups. The 9 patients in the LDL group underwent LDL-apheresis 1 day before and 5 days after PTCA while the 27 patients of the control group underwent PTCA but did not undergo LDL-apheresis. Follow-up coronary angiography (CAG) was performed 4 months after PTCA. The rate of restenosis of coronary artery lesions was significantly lower in the LDL group (0%) than in the control group (30%). These findings suggest that LDL-apheresis, when performed before and after PTCA, is effective in preventing restenosis of coronary artery lesions in patients with CHD and hypercholesterolemia.  相似文献   
52.
A 50 year old man with a two month history of upper abdominal pain and a one month history of anorexia and weight loss, presented with icterus and evidence of peritonitis. Laparotomy revealed biliary peritonitis which had been caused by a rupture of the fundus of the gallbladder. The common bile duct was dilated and there was a large growth in the head of the pancreas with multiple hepatic metastases. A cholecysto-jejunostomy and gastrojejunostomy were done and the patient had an uneventful recovery.  相似文献   
53.
为探讨冠心病患者血糖与微量元素的关系,用电感耦合等离子体原子发射光谱法测定了78例冠心病患者的6种微量元素变化,并与血糖做相关分析.结果冠心病患者高血糖组与正常血糖组相比,血清铁、铅、镉显著增高,锌和铬显著降低,P<005或001,铜无显著性差异;血糖与血清铁、铅呈显著性正相关,与血清铬、锌呈显著负相关,而与铜、镉相关不显著.表明部分微量元素的不平衡构成对冠心病的危险因子———高血糖的促发作用,调整人群中微量元素的不平衡状态,对减少冠心病及糖尿病的发生可能有利  相似文献   
54.
PURPOSE: To evaluate the effect of long-term treatment with metoprololafter coronary bypass grafting on death and cardiac events. METHODS: Patients in western Sweden on whom coronary artery bypass graftingwas performed between June 1988 and June 1991 were evaluatedfor inclusion during the first 3 weeks after surgery. Majorexclusion criteria were age >75 years, concomitant valvesurgery, traditional contraindications to beta-blockers andunwillingness to participate. Patients were randomized in adouble-blind fashion to 100 mg of metoprolollplacebo daily for2 weeks and thereafter 200 mg daily for 2 years. RESULTS: Of 2365 patients who were operated on, 967 were randomized toeither metoprolol (n=480) or placebo (n=487). Primary end points(death, non-fatal myocardial infarction, unstable angina pectoris,need for coronary artery bypass grafting or percutaneous transluminalangioplasty), were reached by 42 patients in the metoprololgroup (8·8%) as compared with 39 in the placebo group(8·0%) (P=0·73). Of all the patients randomizedto metoprolol, 34% withdrew from blind treatment prematurelycompared with 44% for placebo (P<0·01) CONCLUSION: Prophylactic treatment with metoprolol over a 2-year periodafter coronary artery bypass grafting did not reduce death orthe development of cardiac events. However, the 95% confidencelimits ranged from the possibility of a 30% reduction in eventsto a 68% increase in events if patients were treated with metoprololas compared with placebo.  相似文献   
55.
冠心病患者血脂异常与胰岛素抵抗的关系   总被引:12,自引:5,他引:7  
目的 :探讨冠心病患者血脂异常与胰岛素抵抗的关系。方法 :观察 68例冠心病患者与 66例对照者的血脂、血糖、胰岛素等生化指标 ,以胰岛素释放指数———空腹胰岛素 (FIns) /空腹血糖 (FBG)和胰岛素敏感指数(1 /FBG×FIns)作为胰岛素抵抗 (IR)的指标 ,与空腹血脂进行直线相关分析。结果 :冠心病组与对照组对比 ,血糖水平无明显差异 (P >0 .0 5) ,而血胰岛素、胰岛素释放指数明显较对照组增高 (P <0 .0 5) ,胰岛素敏感指数明显较对照组低 (P <0 .0 5)。冠心病组的甘油三酯 (TG)、总胆固醇 (TC)、低密度脂蛋白胆固醇 (LDL -C)明显较对照组增高 (P <0 .0 5)、高密度脂蛋白胆固醇 (HDL -C)明显较对照组低 (P <0 .0 5)。冠心病组胰岛素释放指数、胰岛素敏感指数分别与TG ,TC和LDL -C呈正相关 ,与HDL -C呈负相关。结论 :冠心病患者存在着高胰岛素血症和胰岛素抵抗 ,而且冠心病患者的胰岛素抵抗和血脂异常密切相关。  相似文献   
56.
1992~1993年间为180例冠脉病变的病人施行冠脉搭桥术,全部病人均采用核甙抑制剂利多氟嗪预处理和低温(28℃)间断缺血心停搏进行术中心肌保护。平均每例病人作冠状动脉端吻合3~4个,每个吻合口用9分钟,主动脉阻断累加时间约25分钟,体外循环时间90分钟,术后医院死亡率1.6%(3/180),无术后心梗发生。作者认为,冠脉搭桥术的术中心肌保护可采用核甙抑制剂和间断缺血心停搏方法,而不用心肌停搏液。  相似文献   
57.
Osteoporosis and Coronary Atherosclerosis in Asymptomatic Postmenopausal Women   总被引:23,自引:9,他引:14  
Estrogen deficiency is a risk factor for osteoporosis and coronary artery disease. Osteoporosis can be evaluated by measuring bone mineral density (BMD). Coronary atherosclerotic burden can be evaluated by measuring coronary calcium using electron beam computed tomography (EBT) of the heart. We compared coronary calcium scores in 45 asymptomatic postmenopausal women with normal and low BMD. BMD of the lumbar spine and proximal femur was measured by dual X-ray absorptiometry (DXA), and coronary calcium was measured quantitatively by EBT. Women were divided into control, osteopenia, and osteoporosis groups based on the T score of the lumbar spine. Women were similar in age, years since menopause, height, weight, and body mass index (BMI). BMD ± SD (g/cm2) of L1–L4 was 0.96 ± 0.11, 0.83 ± 0.03, and 0.73 ± 0.05, in control, osteopenia, and osteoporosis group, respectively. The total coronary calcium score ± SD (relative units) was 41.9 ± 83.1, 115.1 ± 181.9, and 221.7 ± 355.4 for control, osteopenia, and osteoporosis group, respectively; the score was significantly higher in the osteoporosis than in the control group. This study provides initial data suggesting that women with osteoporosis may have a higher risk of developing coronary atherosclerosis.  相似文献   
58.
选择32颗新近拔除的磨牙,3号球钻由冠方进入造成髓底穿孔,分为4个实验组,分别充以氧化锌丁香油糊剂、氢氧化钙糊剂、磷酸锌水门汀及玻璃离子粘固粉,丁氧膏密封牙合面。各牙表面涂指甲油后,浸入1%中性红染液,10天后取出,测各牙穿孔处染液渗入高度。结果显示:实验组染液渗入高度1组<2组<3组<4组,提示4种材料相比,氧化锌丁香油糊剂用于底穿修复的密封性能最好。  相似文献   
59.
汽车驾驶员心电多相频谱分析   总被引:2,自引:0,他引:2  
对117例汽车司机应用HBD-1心电多信息诊断仪进行心电多相频谱分析,其功率谱,传递相移,幅度直方图等五项指标总分阳性率明显高于对照组,随着驾车年限的增加,总分阳性率有升高趋势,心电频谱分析对230例冠心病病人阳性检出率84.78%。研究认为汽车司机是易发高血压,冠心病的危险人群,该方法在冠心病的环境流行病学研究中具有重要的临床,亚临床意义。  相似文献   
60.
A quantified evaluation of planar cardiac perfusion scintigrams (the objective of the study), obtained using technetium-99m methoxyisobutylisonitrile (MIBI) was performed on the basis of an analysis of circumferential profile curves, representing the perfusion as seen in three typical projections. The analysis involved the curves obtained both at rest and after stress, and was based on a comparison of their shape (trend) with the normal trend (normative evaluation). The latter was obtained by means of an original method of iterative fitting of individual curves into the database. The base consisted of curves recorded in 53 patients (separately in males and females) with normal perfusion of the left ventricle (group I, the reference group). A group of 90 patients suspected of having coronary artery disease (group II) was subdivided into two subgroups on the basis of coronary arteriography: (a) those with and (b) those without critical stenosis of at least one artery. Profile curves characterising the LV perfusion were obtained at rest and after stress. Defects of perfusion were quantified by comparison of individual curves with the normal trends. By means of multivariate analysis it was demonstrated that vectors of mean values characterising the scintigraphically assessed defects of LV perfusion in the two subgroups of group II differed very significantly (P<10–5). Applying methods of discriminant analysis, a classification of patients from group II was performed into those with probable defects of perfusion and those free of such defects. The sensitivity, specificity and accuracy of diagnosis of coronary ischaemia, based on quantified planar99mTc-MIBI scintigraphy, reached 86%, 87% and 87%, respectively.  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