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   48195篇
  免费   4344篇
  国内免费   1502篇
耳鼻咽喉   596篇
儿科学   571篇
妇产科学   751篇
基础医学   5083篇
口腔科学   529篇
临床医学   7238篇
内科学   5491篇
皮肤病学   178篇
神经病学   13099篇
特种医学   6190篇
外国民族医学   12篇
外科学   3827篇
综合类   4724篇
现状与发展   1篇
预防医学   1012篇
眼科学   497篇
药学   2113篇
  10篇
中国医学   727篇
肿瘤学   1392篇
  2024年   271篇
  2023年   1093篇
  2022年   2016篇
  2021年   2621篇
  2020年   2456篇
  2019年   2283篇
  2018年   1961篇
  2017年   1988篇
  2016年   1794篇
  2015年   1772篇
  2014年   3043篇
  2013年   2974篇
  2012年   2360篇
  2011年   2661篇
  2010年   2165篇
  2009年   2220篇
  2008年   2200篇
  2007年   2115篇
  2006年   2036篇
  2005年   1757篇
  2004年   1404篇
  2003年   1342篇
  2002年   1201篇
  2001年   936篇
  2000年   702篇
  1999年   637篇
  1998年   577篇
  1997年   527篇
  1996年   527篇
  1995年   456篇
  1994年   445篇
  1993年   322篇
  1992年   316篇
  1991年   261篇
  1990年   234篇
  1989年   220篇
  1988年   178篇
  1987年   167篇
  1986年   151篇
  1985年   237篇
  1984年   208篇
  1983年   161篇
  1982年   163篇
  1981年   145篇
  1980年   143篇
  1979年   127篇
  1978年   100篇
  1977年   78篇
  1976年   81篇
  1974年   52篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
971.
Aims/hypothesis This study aimed to examine brain energy metabolism during moderate insulin-induced hypoglycaemia in Type 1 diabetic patients and healthy volunteers.Methods Type 1 diabetic patients (mean diabetes duration 13±2.5 years; HbA1c 6.8±0.3%) and matched controls were studied before, during (0–120 min) and after (120–240 min) hypoglycaemic (~3.0 mmol/l) hyperinsulinaemic (1.5 mU·kg–1·min–1) clamp tests. Brain energy metabolism was assessed by in vivo 31P nuclear magnetic resonance spectroscopy of the occipital lobe (3 Tesla, 10-cm surface coil).Results During hypoglycaemia, the diabetic patients showed blunted endocrine counter-regulation. Throughout the study, the phosphocreatine:-ATP ratios were lower in the diabetic patients (baseline: controls 3.08±0.29 vs diabetic patients 2.65±0.43, p<0.01; hypoglycaemia: 2.97±0.38 vs 2.60±0.35, p<0.05; recovery: 3.01±0.28 vs 2.60±0.35, p<0.01). Intracellular pH increased in both groups, being higher in diabetic patients (7.096±0.010 vs. 7.107±0.015, p<0.04), whereas intracellular magnesium concentrations decreased in both groups (controls: 377±33 vs 321±39; diabetic patients: 388±47 vs 336±68 µmol/l; p<0.05).Conclusions/interpretation Despite a lower cerebral phosphocreatine:-ATP ratio in Type 1 diabetic patients at baseline, this ratio does not change in control or diabetic patients during modest hypoglycaemia. However, both groups exhibit subtle changes in intracellular pH and intracellular magnesium concentrations.Abbreviations [Mg2+]i intracellular magnesium - NMR nuclear magnetic resonance - PCr phosphocreatine - pHi intracellular pH - Pi intracellular inorganic phosphate  相似文献   
972.
在临床中,准确评价淋巴结的情况对肿瘤患者治疗方案的选择及预后的判断具有重要的意义。影像学判断良、恶性淋巴结常以淋巴结的大小、形态、有无中心坏死以及有无包膜外侵袭等来作为参考标准,但这些指标的敏感性和可靠性均较低,转移性淋巴结直径可以很小,而且并不是所有直径较大的淋巴结都是恶性。近年来,磁共振弥散加权成像在鉴别良、恶性病变成为研究的热点,本文对弥散加权成像在淋巴结的应用及研究现状予以综述。  相似文献   
973.
One hundred and twenty excised rabbits hearts were subjected to 1 h of continuous pulsatile coronary perfusion with acellular fluids in a Lindbergh-Rockefeller Institution organ perfusion apparatus. Perfusions were carried out at 26°C and 15°C. At the end of 1 h of perfusion, samples of the left ventricular myocardium were packed into nuclear magnetic resonance (NMR) tubes and the water peak area and linewidth of the water signal were determined by the steady-state NMR spectroscopy. Seventeen different perfusates were employed. Four hearts were perfused and one control heart was processed in an identical way, with each set of experiments. Results were expressed as the mean percentage increase in total myocardial water in perfused hearts, as compared to unperfused hearts. At 26°C these ranged from 9.31 (s.e. 0.66) to 35.89 (s.e. 4.09). At 15°C the range was from 13.26 (s.e. 1.03) to 39.14 (s.e. 2.06). At 26°C, the mean linewidth (Hz) in control myocardiums was 11.60 (s.e. 0.40), in perfused hearts 7.34 (s.e. 0.33); at 15°C it was 12.15 (s.e. 0.29) in control hearts, and 7.84 (s.e. 0.37) in perfused ones. Hearts perfused with lactated Ringer's solution showed the greatest interstitial water accumulation. Linewidth narrowing indicated an accumulation of “unstructured” presumably extracellular water. In edematous hearts, interstitial spaces were widely dilated. The described technique can serve as a rapid screening method for assessing myocardial edema produced by perfusion.  相似文献   
974.
975.
In this study, we analyzed two cases of pure cerebral fat embolism and reviewed related literatures to explore the pathogenesis, clinical manifestations, diagnosis and treatment of cerebral fat embolism, improve the treatment efficiency and reduce the misdiagnosis rate. In our cases, patients fully returned to consciousness at the different times with good prognosis, normal vital signs and without obvious sequelae. For patients with the limb fractures, who developed coma without chest distress, dyspnea or other pulmonary symptoms 12 or 24 h post injury, cerebral fat embolism should be highly suspected, except for those with intracranial lesions, such as delayed traumatic intracerebral hemorrhage, etc. The early diagnosis and comprehensive treatment can improve prognosis.  相似文献   
976.
977.
We describe a case of unrecognized rectal puncture following unsuccessful caudal blockade in a patient later found to have marked rectal distension on MRI. This may have contributed to the rectal injury.  相似文献   
978.
979.
980.
Clinical experience with a new electrical stimulation (ES) technique, the wireless micro current stimulation (WMCS), for the treatment of chronic wounds is described. WMCS transfers the current to any surface wound from a distance, by using oxygen's and nitrogen's ability to exchange electrons. We studied 47 patients with hard‐to‐heal wounds. Patients with venous, arterial and mixed leg ulcers were predominant; other aetiologies such as diabetic foot lesions, pressure ulcers, vasculitis and pyoderma were also included. WMCS treatment protocol specified treatment twice or thrice per week, for 45–60 minutes per session, with 1·5 μA current intensity. Standard wound care was applied to all patients, including compression bandages, if necessary. Clear progress of wound healing, even after 2 weeks, was observed in all cases. The mean reduction of the wound surface after WMCS treatment was 95% in 8 weeks. Complete healing was achieved within 3 months for the majority of the cases. No clinical side effects were observed. WMCS technology significantly accelerated wound healing for patients with hard‐to‐heal wounds of different aetiologies. This new therapy offers multiple advantages compared with the previous methods of ES, as it is contactless, free of pain and very easy to use.  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