全文获取类型
收费全文 | 3575篇 |
免费 | 239篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 38篇 |
儿科学 | 33篇 |
妇产科学 | 70篇 |
基础医学 | 488篇 |
口腔科学 | 54篇 |
临床医学 | 357篇 |
内科学 | 907篇 |
皮肤病学 | 45篇 |
神经病学 | 381篇 |
特种医学 | 137篇 |
外科学 | 626篇 |
综合类 | 9篇 |
一般理论 | 1篇 |
预防医学 | 88篇 |
眼科学 | 45篇 |
药学 | 283篇 |
中国医学 | 3篇 |
肿瘤学 | 267篇 |
出版年
2023年 | 30篇 |
2022年 | 135篇 |
2021年 | 152篇 |
2020年 | 72篇 |
2019年 | 94篇 |
2018年 | 89篇 |
2017年 | 57篇 |
2016年 | 92篇 |
2015年 | 106篇 |
2014年 | 129篇 |
2013年 | 160篇 |
2012年 | 232篇 |
2011年 | 267篇 |
2010年 | 152篇 |
2009年 | 113篇 |
2008年 | 211篇 |
2007年 | 254篇 |
2006年 | 191篇 |
2005年 | 225篇 |
2004年 | 195篇 |
2003年 | 183篇 |
2002年 | 160篇 |
2001年 | 52篇 |
2000年 | 42篇 |
1999年 | 34篇 |
1998年 | 32篇 |
1997年 | 15篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 12篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 9篇 |
1989年 | 14篇 |
1988年 | 15篇 |
1987年 | 8篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1979年 | 15篇 |
1976年 | 8篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1973年 | 23篇 |
1972年 | 19篇 |
1970年 | 9篇 |
1969年 | 12篇 |
1968年 | 8篇 |
1967年 | 10篇 |
排序方式: 共有3832条查询结果,搜索用时 15 毫秒
1.
The aim of this study was to determine whether repeated maximum inspiratory vital capacity manoeuvres against a fixed resistance increased effective short-term sputum clearance in adults with cystic fibrosis (CF). Twenty adults with CF were randomised to receive, on alternate days, either standardised physiotherapy (SP) for 30 min, comprising postural drainage and the active cycle of breathing technique, or a series of resistive inspiratory manoeuvres (RIM) at 80% of their maximum sustained inspiratory pressure developed between residual volume and total lung capacity during the first 4 days of the treatment of an exacerbation of respiratory symptoms. Expectorated sputum was collected during and for 30 min after each treatment and weighed. Total protein, immunoreactive interleukin (IL)-8 and human neutrophil elastase (HNE) concentrations, and the amount of each component expectorated, were determined. Compared with SP, RIM increased sputum weight two-fold, independent of treatment order or day. The concentrations of protein, IL-8 and HNE in sputum were similar for both treatments, while the quantity expectorated was greater with RIM treatment. In conclusion, short-term resistive inspiratory manoeuvres treatment was more effective at clearing sputum and inflammatory mediators than standardised physiotherapy. 相似文献
2.
E M?gureanu C Busuioc V Ionescu E Guguianu A Stoicescu R Murgoci D Cristescu V Stoicescu 《Virologie》1989,40(3):171-181
The study describes the peculiarities of the influenza infection evolution, in 1988, in a large urban centre, B., in Romania, as they result from the active surveillance of the epidemiological process of influenza and other viral respiratory tract infections, by means of a complex methodology based on clinical-epidemiological and laboratory techniques. The low endemic morbidity, the evolution of these seasonally ascendant specific incidence, the endemic aspect of influenza infection being maintained as a consequence of its predominance in infants and children, the clinically mild form of the outbreaks, all these are specific elements of the epidemiologic impact in the surveyed territory. They are discussed in accordance with the results of laboratory tests (seroepidemiologic and diagnostic) that confirmed the permanent circulation of influenza virus types A(H1N1), A(H3N2) and B in all age groups. 相似文献
3.
M Chidambaram S A Abdulali B G Baliga M I Ionescu 《The Annals of thoracic surgery》1987,43(2):185-188
DeVega tricuspid annuloplasty was performed in 74 patients undergoing mitral or mitral and aortic valve replacement between January, 1972, and December, 1985. Sixty-two hospital survivors have been followed up for a mean of 85.3 +/- 6.6 months. Actuarial survival at 14 years was 71.5 +/- 8.2%. None of the late deaths was related to the tricuspid annuloplasty. Three patients required tricuspid valve replacement for recurrence of tricuspid regurgitation (0.68% per annum). Eleven asymptomatic patients studied hemodynamically at a mean period of 53 months after the operation showed maintenance of the hemodynamic improvement. We recommend DeVega annuloplasty as the method of choice for moderate to severe tricuspid regurgitation in the absence of an organically diseased or deformed valve. 相似文献
4.
CLOTBUST: Design of a Randomized Trial of Ultrasound-Enhanced Thrombolysis for Acute Ischemic Stroke 总被引:4,自引:0,他引:4
Andrei V. Alexandrov MD Anne W. Wojner PhD James C. Grotta MD 《Journal of neuroimaging》2004,14(2):108-112
BACKGROUND: Intravenous tissue plasminogen activator (TPA) therapy can be monitored with 2 MHz transcranial Doppler (TCD). This article describes the design of CLOTBUST (combined lysis of thrombus in brain ischemia using transcranial ultrasound and systemic TPA), the first prospective international multicenter randomized clinical trial of noninvasive externally applied ultrasound to enhance systemic thrombolysis in human stroke. SUBJECTS: Patients with acute ischemic stroke eligible for intravenous TPA therapy within 3 hours of symptom onset who have detectable middle cerebral artery occlusion on a prebolus TCD are included in this trial. All patients receive standard 0.9 mg/kg TPA therapy. Patients are randomized (1:1) to either 2 hours of continuous monitoring with TCD or placebo monitoring. FDA-approved portable diagnostic TCD equipment and standard headframes (Marc series, Spencer Technologies, Seattle, WA) are used. Output of TCD units is set at 100% power achievable at depths of insonation that display the worst TIBI flow grade signals. METHODS AND END-POINTS: Acute MCA occlusion on prebolus TCD is defined as thrombolysis in brain ischemia (TIBI) flow grades 0-3. Treating physicians are blinded to randomization assignment, and certified scorers measure stroke severity using the National Institute of Health Stroke Scale (NIHSS). Safety of continuous TCD monitoring is determined by rates of symptomatic (NIHSS score increase by 4+ points) intracerebral hemorrhage within 72 hours after initial symptom onset. Potential enhancement of TPA therapy will be determined using combined primary end-point of early complete recanalization on TCD (TIBI flow grades 4-5), dramatic recovery (NIHSS < or = 3 points), or decline in the NIHSS > or = 10 points repeatedly measured every 30 minutes within 2 hours after TPA bolus. Other end-points include recovery at 24 hours and 3 months, modified Rankin scores (mRS) are obtained at 90 days, and favorable outcome is determined as NIHSS or mRS scores 0-1. CONCLUSIONS: The aim of phase II CLOTBUST trial is to determine the rates of early complete recanalization and dramatic/early clinical recovery in TPA + TCD and TPA groups. The sample size is set at 126 patients since a medium effect size (.50) is anticipated for TPA + TCD group vs TPA alone to achieve combined primary end-point. 相似文献
5.
Sofya N Pchelina Andrei F Yakimovskii Olga N Ivanova Anton K Emelianov Andrei H Zakharchuk Alexander L Schwarzman 《Movement disorders》2006,21(12):2234-2236
Among mutations associated with autosomal dominant and sporadic Parkinson's disease (PD) the G2019S substitution in the leucine-rich repeat kinase 2 (LRRK2) gene is the most frequently identified. To estimate its frequency in Russia, we analyzed 208 patients with PD from the Northwestern region of Russia. Of these, 51 patients were probands from families with PD compatible with autosomal dominant inheritance. The control group represented 161 subjects without neurological disorders settled in the same region. The frequency of the G2019S mutation was greater in familial PD (2 [3.9%] of 51) than in sporadic PD (1 [0.6%] of 157). In addition, this mutation was found in the proband's father, who also had PD, in 1 PD family, and in 1 carrier without signs of PD at age 40 in another PD family. All carriers were heterozygous for the G2019S mutation and reported the Ashkenazi Jewish origin. The mutation was not found in the control group. 相似文献
6.
Anne W Wojner Lewis Morgenstern Andrei V Alexandrov Diana Rodriguez David Persse James C Grotta 《American journal of critical care》2003,12(5):411-417
BACKGROUND: Rapid diagnosis and transport by paramedics and efficient, effective emergency management are essential to improving care of acute stroke patients. OBJECTIVES: To measure the performance of paramedics and emergency departments providing care for patients with suspected acute stroke. METHODS: Two stroke centers and 4 other hospitals where most patients with acute stroke in Houston, Tex, are admitted participated. Hospital and paramedic performance data were collected prospectively on 446 patients with suspected acute stroke transported by paramedics between September 1999 and February 2000. RESULTS: Paramedics had a sensitivity of 66%, specificity of 98%, and overall accuracy of 72% in diagnosing stroke. For patients with suspected stroke, 58.5% arrived in the emergency department within 120 minutes of symptom onset; in confirmed cases, that percentage was 67%. Mean total transport time was 42.2 minutes and was significantly longer (P < .001) to inner-city hospitals (44 minutes) than to suburban, community-based centers (39 minutes). Door to computed tomography times were significantly (P < .001) shorter for the 2 stroke centers than the other hospitals. Overall thrombolysis treatment rate among patients with confirmed ischemic stroke was 7.4% (range, 0-19.4%); treatment rates at the 2 stroke centers were 5.9% and 19.4%. CONCLUSIONS: More than half of patients with suspected stroke arrive at hospitals while thrombolytic treatment is still feasible. Although the current rate for thrombolytic treatment in Houston exceeds the national rate, performance of paramedics and hospitals in treating acute stroke can be improved by increasing efficiency and standardizing medical practices. 相似文献
7.
Residual Flow Signals Predict Complete Recanalization in Stroke Patients Treated With TPA 总被引:4,自引:0,他引:4
Lise A. Labiche MD Marc Malkoff MD Andrei V. Alexandrov MD 《Journal of neuroimaging》2003,13(1):28-33
BACKGROUND: Residual blood flow around thrombus prior to treatment predicts success of coronary thrombolysis. The authors aimed to correlate the presence of residual flow signals in the middle cerebral artery (MCA) with completeness of recanalization after intravenous tissue plasminogen activator (TPA). METHODS: The authors studied consecutive patients treated with intravenous TPA therapy who had a proximal MCA occlusion on pretreatment transcranial Doppler (TCD). Patients were continuously monitored for 2 hours after TPA bolus. Absent residual flow signals correspond to the thrombolysis in brain ischemia (TIBI) 0 grade, and the presence of residual flow signals was determined as TIBI 1-3 flow grades. Complete recanalization was defined as flow improvement to TIBI grades 4-5. RESULTS: Seventy-five patients with a proximal MCA occlusion had median pre-bolus NIHSS 16 (85% with > or = 10 points). TPA bolus was given at 141 +/- 56 minutes (median 120 minutes). Complete recanalization was observed in 25 (33%), partial in 23 (31%), and no early recanalization was seen in 27 (36%) patients within 2 hours after TPA bolus. Only 19% with absent residual flow signals (TIBI grade 0, n = 26) on pretreatment TCD had complete early recanalization. If pretreatment TCD showed the presence of any residual flow (TIBI 1-3, n = 49), 41% had complete recanalization within 2 hours of TPA bolus (P = .03). CONCLUSIONS: Patients with detectable residual flow signals before IV TPA bolus are twice as likely to have early complete recanalization. Those with no detectable residual flow signals have less than 20% chance for complete early recanalization with intravenous TPA and may be candidates for intra-arterial therapies. 相似文献
8.
Free plasma catecholamines were measured by means of a standardized HPLC method in 41 adult patients with severe atopic eczema and in 18 healthy volunteers. The circulating norepinephrine levels were significantly higher in the atopic group (P less than 0.005), by contrast only slight differences were found in the epinephrine and dopamine concentrations. The possible mechanisms leading to these changes at concomitant normal DBH activities are discussed. 相似文献
9.
10.