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   53167篇
  免费   3069篇
  国内免费   488篇
耳鼻咽喉   711篇
儿科学   1986篇
妇产科学   913篇
基础医学   7036篇
口腔科学   1126篇
临床医学   4217篇
内科学   12223篇
皮肤病学   1527篇
神经病学   4616篇
特种医学   1312篇
外国民族医学   2篇
外科学   6500篇
综合类   1339篇
一般理论   30篇
预防医学   4867篇
眼科学   1384篇
药学   3440篇
  6篇
中国医学   504篇
肿瘤学   2985篇
  2024年   68篇
  2023年   403篇
  2022年   500篇
  2021年   1471篇
  2020年   804篇
  2019年   1515篇
  2018年   2238篇
  2017年   1375篇
  2016年   1249篇
  2015年   1260篇
  2014年   1510篇
  2013年   2372篇
  2012年   3963篇
  2011年   4368篇
  2010年   2174篇
  2009年   1384篇
  2008年   3323篇
  2007年   3469篇
  2006年   3158篇
  2005年   3237篇
  2004年   2957篇
  2003年   2852篇
  2002年   2578篇
  2001年   1650篇
  2000年   2004篇
  1999年   1177篇
  1998年   395篇
  1997年   281篇
  1996年   290篇
  1995年   231篇
  1994年   166篇
  1993年   181篇
  1992年   232篇
  1991年   180篇
  1990年   165篇
  1989年   165篇
  1988年   159篇
  1987年   119篇
  1986年   106篇
  1985年   107篇
  1984年   115篇
  1983年   73篇
  1982年   84篇
  1981年   77篇
  1980年   60篇
  1979年   40篇
  1978年   50篇
  1977年   44篇
  1976年   35篇
  1973年   31篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The purpose of this study was to evaluate the ability of helical computed tomographic angiography (HCTA) to detect vascular injury in penetrating neck trauma. Thirty-five patients (30 gunshot wounds and 5 stab wounds) were studied prospectively with HCTA. Scans were performed with a 5-mm slice thickness at a 1:1 pitch after injection of 90 ml of nonionic contrast medium (30-second delay) at 3 ml/sec. Results were compared with those for angiography (29), surgery (3), ultrasound (2), and local inspection (1). HCTA correctly revealed 19 normal and 10 abnormal studies. In 8 cases, HCTA revealed irregular vessel margins (3), contrast extravasation (2), lack of vascular enhancement (1), and caliber changes (2). In 2 patients, HCTA revealed indirect signs of injury only. In 6 cases, HCTA findings did not correlate with angiography. HCTA detects both direct and indirect signs of vascular injury. Although indirect findings are more sensitive, the direct evaluation of vessels increases the specificity and has a high negative predictive value.  相似文献   
42.
In 2003 through 2005, the California Statewide Area Health Education Centers (AHEC) Program developed an educational delivery system, through partnerships with six AHECs and state organizations concerned with emergency preparedness, to train for public health emergency preparedness the health professionals who practice primarily in the state's medically underserved areas. Four educational modules--General Emergency Preparedness, Bioterrorism, Chemical and Radiologic Agents, and Emerging Infections--were developed and delivered by a trained, multidisciplinary, community-based faculty. The authors discuss the organization, partnerships, curriculum, faculty, characteristics of trainees, outcomes of the program, effects for AHECs, and the evaluation used to commit the organization and program process to the intended program objectives during the two-year period. Over 9,000 health professionals attended one or more of the 462 educational presentations. Approximately one third of attendees were physicians, and 82% of the learners were from sites that typically care for the underserved. Important to the success of the program (which still continues in a revised form) were the types of partnerships, an orientation of the curriculum to all-hazards disaster preparedness, the delivery of educational sessions at clinical sites, and the increased capacities of community AHECs to facilitate continuing professional education. The challenges were the diminished role of a key partner organization, uncertainties within the funding agency, and the widespread geographic area to address.  相似文献   
43.
This paper presents the results of a qualitative study conducted by midwife researchers into women's experience of new motherhood. Data were collected using focus groups involving 55 first-time mothers and analysed using grounded theory method. The analysis produced six categories: 'realizing', 'unready', 'drained', 'aloneness', 'loss' and 'working it out'. The core category, 'becoming a mother', integrates all other categories and encapsulates the process of change experienced by women. Also explained are factors mediating the often distressing experience of becoming a mother. The analysis provides a conceptualization of early motherhood enabling the development of strategies for midwives, nurses and others helping women negotiate this challenge.  相似文献   
44.
Adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine and uric acid were determined in cerebrospinal fluid (CSF) of 15 children after complex febrile seizures (CFS) and in 27 after simple febrile seizures (SFS), and compared with those in a control group of 63 children. There was no statistically significant difference between the groups for any of these metabolites, suggesting that CFS and SFS neither significantly disturb the metabolism of nucleotides, nucleosides or bases nor significantly deplete neuron adenosine triphosphate levels.  相似文献   
45.
PURPOSE: To compare two protocols of epidural administration of racemic methadone for postoperative analgesia (continuous infusion and intermittent bolus), focussing on plasma concentration, analgesic efficacy and side effects. METHODS: Ninety patients undergoing abdominal or lower-limb surgery were randomly assigned to two groups in a prospective double-blind design. The continuous infusion patients (n=60) received initial doses of 3 to 6 mg followed by 6 to 12 mg by continuous infusion over 24 hr. The bolus administration patients (n=30) received repeated boluses of 3 to 6 mg of racemic methadone every eight hours. Pain intensity was assessed on a visual analog scale. Amount of supplementary analgesia was recorded, as was the incidence of side effects. Plasma methadone concentrations were determined by high performance liquid chromatography. Treatment was continued for 72 hr. RESULTS: Pain relief was good and comparable in both groups throughout the three days of treatment. No accumulation of plasma racemic methadone was observed in either group, although the concentrations were significantly higher in the bolus group. Miosis was significantly more frequent in the bolus group. CONCLUSION: Plasma methadone concentrations were significantly lower with continuous infusion. Plasma methadone accumulation, which is considered the main disadvantage for its purported influence on the incidence of side effects, did not occur at the doses used over the three days of treatment that we report.  相似文献   
46.
47.
48.
49.
50.
Summary To characterize the pineal response to pyridoxine, plasma melatonin was measured in one hundred and twenty children 3 hours after vitamin B6 administration. The children, aged between 1.5 and 8 years, were divided in four groups as follows: a) control day group, grouping 27 children sampled at 9:00 and at 12:00; b) control night group, grouping 29 children sampled at 21:00 and at 24:00; c) pyridoxine day group, grouping 30 children sampled at 9:00, then intravenously (i.v.) injected with 3mg/kg of pyridoxine, and sampled at 12:00; and d) pyridoxine night group, grouping 34 children sampled at 21:00, i.v. injected with 3mg/kg of pyridoxine, and sampled at 24:00. Melatonin concentration was measured by radioimmuno assay. The data obtained showed a significant increase in melatonin levels after pyridoxine administration in the pyridoxine night group (39.87 ± 8.02pg/ml basal vs 88.45 ± 9.21 pg/ml after pyridoxine, p < 0.001). The other groups did not showed significant differences in melatonin concentrations. Statistical analysis shows that the administration of pyridoxine during the nocturnal hours represents a stimulating factor to increase the pineal production of melatonin in children.  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