全文获取类型
收费全文 | 3226555篇 |
免费 | 248432篇 |
国内免费 | 5627篇 |
专业分类
耳鼻咽喉 | 47232篇 |
儿科学 | 102495篇 |
妇产科学 | 89434篇 |
基础医学 | 459354篇 |
口腔科学 | 92882篇 |
临床医学 | 289339篇 |
内科学 | 626247篇 |
皮肤病学 | 66669篇 |
神经病学 | 265255篇 |
特种医学 | 128162篇 |
外国民族医学 | 1170篇 |
外科学 | 489814篇 |
综合类 | 74140篇 |
现状与发展 | 2篇 |
一般理论 | 1195篇 |
预防医学 | 255040篇 |
眼科学 | 75924篇 |
药学 | 242893篇 |
5篇 | |
中国医学 | 6005篇 |
肿瘤学 | 167357篇 |
出版年
2018年 | 31999篇 |
2016年 | 27207篇 |
2015年 | 30917篇 |
2014年 | 44083篇 |
2013年 | 67454篇 |
2012年 | 91341篇 |
2011年 | 96812篇 |
2010年 | 56973篇 |
2009年 | 54342篇 |
2008年 | 92270篇 |
2007年 | 98988篇 |
2006年 | 100131篇 |
2005年 | 97756篇 |
2004年 | 94261篇 |
2003年 | 90942篇 |
2002年 | 89978篇 |
2001年 | 146227篇 |
2000年 | 151110篇 |
1999年 | 128037篇 |
1998年 | 37279篇 |
1997年 | 33583篇 |
1996年 | 33520篇 |
1995年 | 32284篇 |
1994年 | 30364篇 |
1993年 | 28242篇 |
1992年 | 103590篇 |
1991年 | 100795篇 |
1990年 | 98092篇 |
1989年 | 94788篇 |
1988年 | 88085篇 |
1987年 | 86658篇 |
1986年 | 82333篇 |
1985年 | 78837篇 |
1984年 | 59600篇 |
1983年 | 51045篇 |
1982年 | 30952篇 |
1981年 | 27529篇 |
1980年 | 25802篇 |
1979年 | 56261篇 |
1978年 | 39771篇 |
1977年 | 33685篇 |
1976年 | 31852篇 |
1975年 | 34046篇 |
1974年 | 41424篇 |
1973年 | 39474篇 |
1972年 | 37305篇 |
1971年 | 34548篇 |
1970年 | 32442篇 |
1969年 | 30447篇 |
1968年 | 28187篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
J Vandevoorde S Verbanck D Schuermans J Kartounian W Vincken 《The European respiratory journal》2006,27(2):378-383
The purpose of this study was to determine fixed cut-off points for forced expiratory volume in one second (FEV(1))/FEV(6) and FEV(6) as an alternative for FEV(1)/forced vital capacity (FVC) and FVC in the detection of obstructive and restrictive spirometric patterns, respectively. For the study, a total of 11,676 spirometric examinations, which took place on Caucasian subjects aged between 20-80 yrs, were analysed. Receiver-operator characteristic curves were used to determine the FEV(1)/FEV(6) ratio and FEV(6) value that corresponded to the optimal combination of sensitivity and specificity, compared with the commonly used fixed cut-off term for FEV(1)/FVC and FVC. The data from the current study indicate that FEV(1)/ FEV(6) <73% and FEV(6) <82% predicted can be used as a valid alternative for the FEV(1)/FVC <70% and FVC <80% pred cut-off points for the detection of obstruction and restriction, respectively. The statistical analysis demonstrated very good, overall, agreement between the two categorisation schemes. For the spirometric diagnosis of airway obstruction (prevalence of 45.9%), FEV(1)/FEV(6) sensitivity and specificity were 94.4 and 93.3%, respectively; the positive and negative predictive values were 92.2 and 95.2%, respectively. For the spirometric detection of a restrictive pattern (prevalence of 14.9%), FEV(6) sensitivity and specificity were 95.9 and 98.6%, respectively; the positive and negative predictive values were 92.2 and 99.3%, respectively. This study demonstrates that forced expiratory volume in one second/forced expiratory volume in six seconds <73% and forced expiratory volume in six seconds <82% predicted, can be used as valid alternatives to forced expiratory volume in one second/forced vital capacity <70% and forced vital capacity <80% predicted, as fixed cut-off terms for the detection of an obstructive or restrictive spirometric pattern in adults. 相似文献
82.
Bifid mandibular canal. 总被引:1,自引:0,他引:1
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women. 相似文献
83.
The antiepileptic efficacy and tolerability of oxcarbazepine, used both as monotherapy and adjunctive therapy, were observed for 1 year in 202 adult patients, aged 17-83 years, with newly diagnosed or refractory partial epilepsy in clinical practice in Italy. At first observation, the seizure free rate was 72.2% in newly diagnosed patients given monotherapy, 40% in patients in whom oxcarbazepine replaced another monotherapy and 10.3% in patients given oxcarbazepine as adjunctive therapy. At least 50% reduction in seizure frequency was achieved in 90.7, 72 and 57%, respectively. Efficacy increased with the duration of treatment (p < 0.0001). In the 160 completers the seizure free rate was 61.3% with monotherapy and 28% with adjunctive therapy. 16.3% of patients reported adverse effects, mainly sedation and sleepiness; 5% discontinued oxcarbazepine because of adverse events. OXC is an effective and well-tolerated antiepileptic agent for the long-term treatment of partial epilepsy in adults. 相似文献
84.
Contour defects resulting in deformity caused by lack of tissue can be improved by conventional surgery using autologous tissue, but there is always a donor site morbidity. Integra has been available since the early 1980's for use in acute burns and more recently in reconstruction. It has been shown histologically to act as a tissue regeneration template. The regenerated dermis is buried under an autologous thin split-skin graft. In this study, the principle of burying Integra (without the silicone layer) has been applied to deep tissue defects in 12 reconstructive cases. Such regenerated tissues survive at least 3 years after burying. Modification to the technique to avoid visible edges are being developed. 相似文献
85.
Terry J DuBose 《Journal of ultrasound in medicine》2003,22(12):1420-1; author reply 1421-2
86.
87.
88.
89.
D Yinon L Lowenstein S Suraya R Beloosesky O Zmora A Malhotra G Pillar 《The European respiratory journal》2006,27(2):328-333
Pre-eclamptic toxaemia (PET) may be associated with both endothelial dysfunction (ED) and sleep-disordered breathing (SDB). It was hypothesised that females with PET would demonstrate both SDB and ED, and that a correlation between these two would suggest a potential causative association. A total of 17 females with PET and 25 matched females with uncomplicated pregnancy were studied. They underwent a nocturnal ambulatory sleep study (using Watch_PAT100) and noninvasive evaluation of endothelial function utilising the reactive hyperaemia test (using Endo_PAT 2000). A higher ratio of post- to pre-occlusion pulse-wave amplitude (endothelial function index (EFI)) indicated better endothelial function. Females with PET had a significantly higher respiratory disturbance index (RDI) and lower EFI than controls (18.4+/-8.4 versus 8.3+/-1.3.h(-1), and 1.5+/-0.1 versus 1.8+/-0.1, respectively). Blood pressure significantly correlated with RDI and with EFI. EFI tended to correlate with RDI. In conclusion, these results suggest that both sleep-disordered breathing and endothelial dysfunction are more likely to occur in females with pre-eclamptic toxaemia than in females with uncomplicated pregnancies. The current authors speculate that respiratory disturbances contribute to the functional abnormality of the blood vessels seen in females with pre-eclamptic toxaemia, although causality cannot be determined based on this study. 相似文献
90.
We evaluated the acquisition and performance of a high-precision locomotor task in patients with Parkinson's disease (PD) and healthy subjects. All subjects walked on a treadmill and had to step repetitively as low as possible over an obstacle without touching it. During blocks 1 and 2, the subjects had full vision and received additional acoustic warning and feedback signals. During block 3, vision became restricted. Changes in foot clearance and the number of obstacle hits were evaluated. Initially, PD patients performed poorer and improved foot clearance slower. After task repetition, the groups performed similarly. Restricting vision deteriorated performance in both groups. The similar performance of PD patients after task repetition might indicate that adequate training could improve adaptive locomotor behavior in PD patients. 相似文献