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   3245篇
  免费   277篇
  国内免费   34篇
耳鼻咽喉   21篇
儿科学   85篇
妇产科学   81篇
基础医学   481篇
口腔科学   57篇
临床医学   370篇
内科学   794篇
皮肤病学   43篇
神经病学   192篇
特种医学   224篇
外科学   326篇
综合类   63篇
一般理论   5篇
预防医学   159篇
眼科学   112篇
药学   273篇
中国医学   8篇
肿瘤学   262篇
  2023年   22篇
  2022年   38篇
  2021年   79篇
  2020年   49篇
  2019年   62篇
  2018年   99篇
  2017年   70篇
  2016年   64篇
  2015年   82篇
  2014年   102篇
  2013年   132篇
  2012年   213篇
  2011年   198篇
  2010年   123篇
  2009年   126篇
  2008年   163篇
  2007年   197篇
  2006年   161篇
  2005年   179篇
  2004年   167篇
  2003年   119篇
  2002年   105篇
  2001年   83篇
  2000年   71篇
  1999年   58篇
  1998年   58篇
  1997年   56篇
  1996年   43篇
  1995年   47篇
  1994年   28篇
  1993年   37篇
  1992年   39篇
  1991年   40篇
  1990年   49篇
  1989年   35篇
  1988年   41篇
  1987年   45篇
  1986年   35篇
  1985年   31篇
  1984年   25篇
  1983年   18篇
  1982年   21篇
  1981年   10篇
  1980年   17篇
  1979年   13篇
  1978年   18篇
  1977年   15篇
  1976年   14篇
  1975年   12篇
  1973年   11篇
排序方式: 共有3556条查询结果,搜索用时 31 毫秒
1.
2.
Abstract We report a case of SMV injury in a critically ill patient. The patient was a 19-year-old woman involved in a motor vehicle collision. Her injuries included grade II splenic and renal lacerations, devascularized and lacerated right and transverse colon, a transected transverse mesocolon, a massive shear injury of her abdominal wall, and two partial SMV transections. At initial damage control laparotomy, the SMV was ligated, the devascularized bowel resected and a temporary abdominal closure applied. At re-operation, a mesocaval shunt using saphenous vein was employed. The shunt failed and the patient required a saphenous vein jump graft. Although visceral vascular injuries are rare, ligation of the SMV in a damage control situation is acceptable. This case study is the first to discuss appropriate treatment when interruption to a patient's collateral visceral venous drainage limits the surgeon’s ability to ligate. In these situations, bypass shunts may be successful.  相似文献   
3.
We report a case of successful transvenous, catheter-based, cavotricuspid isthmus ablation for treatment of atrial flutter using microwave energy. Microwave energy was delivered at 900–930 MHz using 21 W of power. Bidirectional cavotricuspid isthmus conduction block was achieved by microwave ablation without any patient discomfort or complication during the procedure. Our initial experience suggests that transcatheter microwave ablation is feasible for the cure of typical atrial flutter.  相似文献   
4.
AIMS: Experimental studies have demonstrated that bone marrow (BM) cells can induce angiogenesis in ischaemic myocardium. Recently, several non-randomized pilot studies have also suggested that direct BM cells implantation appears to be feasible and safe in patients with severe coronary artery diseases (CAD). METHODS AND RESULTS: We performed a randomized, blinded, and placebo-controlled trial in 28 CAD patients. After BM harvesting, we assigned patients to receive low dose (1 x 10(6) cells/0.1 mL, n = 9), high dose (2 x 10(6) cells/0.1 mL, n = 10) autologous BM cells or control (0.1 mL autologous plasma/injection, n = 9) catheter-based direct endomyocardial injection as guided by electromechanical mapping. Our primary endpoint was the increase in exercise treadmill time and our secondary endpoints were changes in Canadian Cardiovascular Society (CCS) and New York Heart Association (NYHA) class, and myocardial perfusion and left ventricular ejection fraction (LVEF) assessed by single-photon emission computed tomography and magnetic resonance imaging, respectively. A total 422 injections (mean 14.6 +/- 0.7 per patient) were successfully performed at 41 targeted ischaemic regions without any acute complication. Baseline exercise treadmill time was 439 +/- 182 s in controls and 393 +/- 136 s in BM-treated patients, and changed after 6 months to 383 +/- 223s and 464 +/- 196 s [BM treatment effect +0.43 log seconds (+53%), 95% CI 0.11-0.74, P = 0.014]. Compared with placebo injection, BM implantation was associated with a significant increase in LVEF (BM treatment effect +5.4%, 95% CI 0.4-10.3, P = 0.044) and a lower NYHA class (odds ratio for treatment effect 0.12, 95% CI 0.02-0.73, P = 0.021) after 6 months, but CCS reduced similarly in both groups. We observed no acute or long-term complications, including ventricular arrhythmia, myocardial damage, or development of intramyocardial tumour or calcification associated with BM implantation. CONCLUSION: Direct endomyocardial implantation of autologous BM cells significantly improved exercise time, LVEF, and NYHA functional class in patients with severe CAD who failed conventional therapy.  相似文献   
5.
6.
麦冬类中药组织切片计算机三维重建图鉴   总被引:9,自引:0,他引:9  
利用计算机技术实现麦冬类中药组织连续切片三维重建与动态显示,为计算机辅助生药学鉴定和教学提供了新的三维图像技术和研究资料。  相似文献   
7.
用混合粘合剂碳糊电极测定丁螺环酮   总被引:6,自引:1,他引:5  
用混合粘合剂碳糊电极测定丁螺环酮张正奇,曾鸽鸣,刘传桂,黎艳飞(湖南大学化学化工系,长沙410082)碳糊电极无毒,制作方便,表面更新容易,应用电位范围广,在药物分析中已有应用[1~5]。我们在液体石腊中加入添加剂,组成混合粘合剂,可显著改善电极的检...  相似文献   
8.
9.
The pharmacokinetics of fluvastatin, a potent inhibitor of hydroxymethylglutaryl-CoA reductase and thus cholesterol synthesis, have been studied in 24 normal male volunteers who received [3H] fluvastatin in three different studies: a single-dose study using oral doses of 2 or 10 mg, an absolute bioavailability study using doses of 2 mg intravenously or 10 mg orally, and a multiple-dose study using 40 mg orally once daily for 6 days. Serial blood and plasma samples and complete urine and feces were collected and analyzed for total radioactivity as well as for intact fluvastatin. Fluvastatin was rapidly and almost completely (greater than 90%) absorbed from the gastrointestinal tract, although the estimated bioavailability from the 2- and 10-mg doses was only 19 to 29% because of extensive first-pass metabolism. Fluvastatin pharmacokinetics appeared to be linear over the 2- to 10-mg dose range, as indicated by dose-proportional blood levels of total radioactivity and the parent drug. Absorbed fluvastatin was completely metabolized before excretion, the biliary/fecal route being the major excretory pathway. The recovery of radioactivity after a single dose was virtually complete within 120 hours. The terminal half-lives of fluvastatin and total radioactivity averaged 0.5 to 1 hour and 55 to 71 hours, respectively, whereas the total body clearance of fluvastatin was 0.97 L/hour/kg. Repeated oral administration of 40-mg doses of [3H]fluvastatin resulted in no time-related change in pharmacokinetic characteristics, but this dose yielded greater than proportional increases in circulating levels of the parent drug, thus suggesting a saturable first-pass effect on fluvastatin.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
10.
1. It is now recognized that atrial fibrillation (AF) is not a benign condition, as it is associated with a 40% increase in mortality and a doubling of the risk of stroke. 2. The development of AF leads to mechanical, electrophysiological and cellular changes in the atria that tend to sustain AF. This process is known as atrial remodelling. 3. The three electrophysiological elements in the atria that initiate and sustain AF are: (i) shortening of the refractory period and an increase in dispersion; (ii) slowing of conduction velocity; and (iii) the presence of triggerin. foci. 4. As AF is a heterogeneous disorder, therapeutic strategies include the use of devices (pacemakers and atrial defibrillators), radiofrequency ablation (focal ablation or the creation of linear lines) and drug therapy that may reverse a remodelle. atrium.  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