全文获取类型
收费全文 | 261182篇 |
免费 | 17514篇 |
国内免费 | 2409篇 |
专业分类
耳鼻咽喉 | 2766篇 |
儿科学 | 6384篇 |
妇产科学 | 4663篇 |
基础医学 | 32047篇 |
口腔科学 | 4897篇 |
临床医学 | 26942篇 |
内科学 | 53457篇 |
皮肤病学 | 3693篇 |
神经病学 | 25066篇 |
特种医学 | 11291篇 |
外国民族医学 | 18篇 |
外科学 | 40727篇 |
综合类 | 6857篇 |
现状与发展 | 5篇 |
一般理论 | 180篇 |
预防医学 | 18430篇 |
眼科学 | 6055篇 |
药学 | 17778篇 |
34篇 | |
中国医学 | 1557篇 |
肿瘤学 | 18258篇 |
出版年
2023年 | 1756篇 |
2022年 | 3175篇 |
2021年 | 6703篇 |
2020年 | 4169篇 |
2019年 | 5935篇 |
2018年 | 6943篇 |
2017年 | 5306篇 |
2016年 | 5730篇 |
2015年 | 6959篇 |
2014年 | 9775篇 |
2013年 | 12899篇 |
2012年 | 19541篇 |
2011年 | 20298篇 |
2010年 | 11692篇 |
2009年 | 10671篇 |
2008年 | 17395篇 |
2007年 | 18145篇 |
2006年 | 17569篇 |
2005年 | 17244篇 |
2004年 | 16075篇 |
2003年 | 14742篇 |
2002年 | 13938篇 |
2001年 | 2456篇 |
2000年 | 1793篇 |
1999年 | 2259篇 |
1998年 | 2936篇 |
1997年 | 2346篇 |
1996年 | 2028篇 |
1995年 | 1849篇 |
1994年 | 1619篇 |
1993年 | 1545篇 |
1992年 | 1069篇 |
1991年 | 981篇 |
1990年 | 835篇 |
1989年 | 803篇 |
1988年 | 714篇 |
1987年 | 664篇 |
1986年 | 687篇 |
1985年 | 721篇 |
1984年 | 941篇 |
1983年 | 813篇 |
1982年 | 1060篇 |
1981年 | 985篇 |
1980年 | 854篇 |
1979年 | 488篇 |
1978年 | 528篇 |
1977年 | 450篇 |
1976年 | 429篇 |
1975年 | 318篇 |
1974年 | 318篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
Noninvasive Intracranial Cerebral Flow Velocity Evaluation in the Emergency Department by Emergency Physicians 总被引:2,自引:0,他引:2
Michael Shafé MD Michael Blaivas MD RDMS Edmond Hooker MD Leigh Straus BS 《Academic emergency medicine》2004,11(7):774-777
Transcranial Doppler (TCD) is an accepted modality for the evaluation of cerebral blood flow velocities. OBJECTIVES: The purpose of this study was to test the feasibility of bedside TCD measurement in the emergency department (ED) with critically ill, intubated patients. METHODS: A prospective convenience sample of patients presenting to a university hospital over a two-month period underwent TCD evaluation of the middle cerebral artery. Intubated patients with head trauma and any patient requiring tracheal intubation were eligible. A 2-MHz Doppler probe was positioned over the temporal bone to acquire blood flow velocities. An emergency medicine resident and research assistant obtained measurements. Continuous TCD tracings were recorded on a video cassette recorder tape for quality assurance review and data collection. Vital signs and therapeutic interventions were also recorded. Flow velocities were measured in cm/s; the peak Resistance Index (RI) was calculated for each patient. RESULTS: A total of 30 patients were enrolled in the study. Adequate tracings were obtained in 25 patients (83%) without a disruption of resuscitation. Tracings could not be obtained in five patients; they were listed as TCD failures. However, in two of these patients, adequate flow velocity tracings were obtained after resuscitation. Four patients were evaluated during tracheal intubation. One patient was monitored successfully during cardiopulmonary resuscitation. The median time required for data acquisition was 1.9 minutes. The mean highest RI for those who expired was 0.84. For those who survived, the mean highest RI was 0.52. The difference of 0.32 was statistically significant (p = 0.04). CONCLUSIONS: Noninvasive blood flow velocity monitoring of the middle cerebral artery using TCD is feasible in the ED when performed at the bedside on intubated patients with traumatic brain injury and others during tracheal intubation and resuscitation. 相似文献
84.
85.
Molecular determinants of cetuximab efficacy. 总被引:17,自引:0,他引:17
Daniel Vallb?hmer Wu Zhang Michael Gordon Dong Yun Yang Jim Yun Oliver A Press Katrin E Rhodes Andy E Sherrod Syma Iqbal Kathleen D Danenberg Susan Groshen Heinz-Josef Lenz 《Journal of clinical oncology》2005,23(15):3536-3544
PURPOSE: To investigate whether mRNA expression levels of cyclin D1 (CCND1), cyclooxygenase 2 (Cox-2), epidermal growth factor receptor (EGFR), interleukin 8 (IL-8), and vascular endothelial growth factor (VEGF), all members of the EGFR signaling pathway, are associated with clinical outcome in patients with EGFR-expressing metastatic colorectal cancer (CRC) treated with cetuximab. PATIENTS AND METHODS: Thirty-nine patients with metastatic CRC, refractory to both irinotecan and oxaliplatin, were enrolled on IMCL-0144 and treated with single-agent cetuximab. The intratumoral mRNA levels of CCND1, Cox-2, EGFR, IL-8, and VEGF were assessed from paraffin-embedded tissue samples using laser-capture microdissection and quantitative real-time polymerase chain reaction. RESULTS: There were 21 women and 18 men with a median age of 64 years (range, 35 to 83 years). Higher gene expression levels of VEGF were associated with resistance to cetuximab (P = .038; Kruskal-Wallis test). The combination of low gene expression levels of Cox-2, EGFR, and IL-8 was significantly associated with overall survival (13.5 v 2.3 months; P = .028; log-rank test). Both findings were independent of skin toxicity that was itself significantly correlated to survival. Patients with a lower mRNA amount of EGFR had a longer overall survival compared with patients that had a higher mRNA amount (7.3 v 2.2 months; P = .09; log-rank test). Patients with lower expression of Cox-2 had a significantly higher rate of grade 2 to 3 skin reactions under cetuximab treatment. CONCLUSION: This pilot study suggests that gene expression levels of Cox-2, EGFR, IL-8, and VEGF in patients with metastatic CRC may be useful markers of clinical outcome in single-agent cetuximab treatment. 相似文献
86.
87.
88.
Angelo Lipira David Limbrick Bruce Haughey Phillip Custer Michael R. Chicoine 《Skull base》2009,19(4):303-309
89.
90.
尼麦角林是一种麦角生物碱衍生物,广泛应用于脑血管病患者认知障碍的治疗。多项临
床前研究显示,尼麦角林对于认知障碍的改善可能与以下因素有关:尼麦角林除能够改善脑循环,
促进神经递质释放外,还具有营养神经及抗氧化等作用。目前的研究认为,尼麦角林能够改善患者
卒中后抑郁相关的情绪障碍以及有效改善血管性痴呆,提高患者的日常生活能力。同时,尼麦角林具
有良好的安全性,目前暂无尼麦角林治疗导致纤维化或麦角中毒的研究报道。本文就尼麦角林在神
经系统的作用机制、临床疗效及安全性进行综述,以期为临床应用提供参考。 相似文献