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   1264516篇
  免费   94871篇
  国内免费   1583篇
耳鼻咽喉   16317篇
儿科学   41055篇
妇产科学   34952篇
基础医学   189445篇
口腔科学   34778篇
临床医学   117809篇
内科学   247899篇
皮肤病学   27285篇
神经病学   101920篇
特种医学   46827篇
外国民族医学   265篇
外科学   178724篇
综合类   25751篇
现状与发展   4篇
一般理论   568篇
预防医学   104694篇
眼科学   28062篇
药学   92588篇
  7篇
中国医学   2023篇
肿瘤学   69997篇
  2018年   13543篇
  2017年   10408篇
  2016年   11349篇
  2015年   13101篇
  2014年   18025篇
  2013年   27511篇
  2012年   37619篇
  2011年   40001篇
  2010年   23082篇
  2009年   22275篇
  2008年   37794篇
  2007年   40420篇
  2006年   39987篇
  2005年   39129篇
  2004年   37576篇
  2003年   35987篇
  2002年   34886篇
  2001年   56058篇
  2000年   57064篇
  1999年   48110篇
  1998年   13404篇
  1997年   12230篇
  1996年   12654篇
  1995年   11921篇
  1994年   11109篇
  1993年   10401篇
  1992年   38208篇
  1991年   37679篇
  1990年   36458篇
  1989年   35265篇
  1988年   32703篇
  1987年   32034篇
  1986年   30530篇
  1985年   28797篇
  1984年   21948篇
  1983年   19195篇
  1982年   11366篇
  1981年   10323篇
  1979年   20948篇
  1978年   15398篇
  1977年   12795篇
  1976年   11850篇
  1975年   12816篇
  1974年   15591篇
  1973年   15365篇
  1972年   14517篇
  1971年   13554篇
  1970年   12788篇
  1969年   12066篇
  1968年   11229篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
BACKGROUND: Bone marrow cell injection has been introduced to treat patients with ischemic heart disease. However, focal application of bone marrow cells may generate an arrhythmogenic substrate. OBJECTIVES: To assess the electrophysiological and arrhythmogenic effects of intramyocardial bone marrow cell injection in patients with chronic myocardial ischemia. METHODS: Bone marrow was aspirated in 20 patients (65+/-11 years, 19 male) with drug-refractory angina and myocardial ischemia. Electroanatomical mapping (NOGA, Biosense-Webster, Waterloo, Belgium) was performed during mononuclear cell isolation. Areas for cell injection were selected based on the localization of ischemia on SPECT. These areas were mapped in detail to evaluate local bipolar electrogram duration, amplitude and fragmentation. Mononuclear cells were injected in the ischemic area with the NOGA system. SPECT and electroanatomical mapping were repeated at 3 months. Holter monitoring was repeated at 3 and 6 months. RESULTS: SPECT revealed a decrease in the number of segments with ischemia (3.5+/-2.5 vs. 1.1+/-1.0 at 3 months; P<0.01) and an increased left ventricular ejection fraction (44+/-13% vs. 49+/-17% at 3 months; P=0.02). The number of ventricular premature beats remained unchanged (10+/-24x10(2)/24h vs. 8+/-23x10(2)/24h at 3 months (P=NS) and 12+/-30x10(2)/24h at 6 months (P=NS)). At 3 months follow-up, bone marrow cell injection did not prolong electrogram duration (15.9+/-4.6 ms vs. 15.6+/-4.0 ms; P=NS), decrease electrogram amplitude (3.8+/-1.5 mV vs. 3.8+/-1.5 mV; P=NS), or increase fragmentation (2.0+/-0.5 vs. 1.9+/-0.4; P=NS). CONCLUSION: Intramyocardial bone marrow cell injection does not increase the incidence of ventricular arrhythmias and does not alter the electrophysiological properties of the injected myocardium.  相似文献   
995.
996.
Two cases of internal herniation through a defect in the broad ligament of the uterus are described. Both were successfully treated laparoscopically. This rare condition should be borne in mind when a middle-aged woman presents with colicky lower abdominal pain. The cause is unknown, but both congenital and acquired origins have been proposed. As far as emergency situations are concerned, laparoscopy has proven to be both a diagnostic and a therapeutic tool.  相似文献   
997.
OBJECTIVES: Local anaesthetic infiltration into the carotid sinus during carotid endarterectomy (CEA) has been recommended to minimise blood pressure fluctuations but its use remains controversial. The aim of this meta-analysis was to determine whether intra-operative administration of local anaesthetic reduces the incidence of haemodynamic instability following CEA. MATERIALS AND METHODS: A search of the Medline, Pubmed and Embase databases and the Current Controlled Trials register identified four trials, which met the pre-defined inclusion criteria for data extraction. Pooled odds ratios with 95 per cent confidence intervals (c.i.) for the development of post-operative hypotension and hypertension were calculated using a random-effects model. RESULTS: Outcomes of 432 patients were studied. Local anaesthetic blockade of the carotid sinus was associated with a pooled odds ratio of 1.25 (95 per cent c.i. 0.496 to 3.15); p=0.216) and 1.28 (95 per cent c.i. 0.699 to 2.33; p=0.428) for the development of post-operative hypotension and hypertension respectively. Although none reach significance there was a trend towards increased risk of developing a complication in those patients who received local anaesthetic. CONCLUSIONS: There are insufficient data to determine the role of intra-operative local anaesthetic administration in reducing post-operative blood pressure lability following CEA. Conversely, the possibility of harm cannot be excluded on the basis of the currently available data.  相似文献   
998.
999.
Trauma und Berufskrankheit - Eine Vielzahl von Präventivmaßnahmen sowie Fortschritte in der medizinischen Akutversorgung von Unfallpatienten führten in den letzten Jahren zu deutlich...  相似文献   
1000.
BACKGROUND: Gastric bypass is an established bariatric procedure that has undergone multiple modifications to improve its effectiveness. The side-to-side stapled technique is well recognized, but closure of the gastrotomy/enterotomy by the stapler can potentially narrow the Roux limb. Because of this, many surgeons will hand suture the closure of the gastrotomy/enterotomy. To obviate this difficulty, we inserted the linear stapler from the stomach's greater curvature, using a double-stapled anastomosis that minimized the need for hand suturing. METHODS: We performed a retrospective analysis of 307 patients undergoing this technique for laparoscopic gastric bypass. The weight loss and 30-day morbidity and mortality were tabulated and compared with those in other published series. RESULTS: Of the 307 patients, none died postoperatively. The overall 30-day morbidity rate was 15%. Two leaks from the gastrojejunostomy and 2 from the jejunojejunostomy (1.2%) developed. The mean percentage of excess weight loss was 34% at 3 months, 52% at 6 months, 73% at 1 year, 71% at 2 years, and 69% at 3 years. CONCLUSION: The greater curve approach avoids Roux limb obstruction, minimizes the need for hand suturing, and uses standard trocar incisions. Our short-term follow-up results are similar to those of series of other techniques.  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