全文获取类型
收费全文 | 671篇 |
免费 | 64篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 5篇 |
妇产科学 | 3篇 |
基础医学 | 99篇 |
口腔科学 | 44篇 |
临床医学 | 69篇 |
内科学 | 100篇 |
皮肤病学 | 7篇 |
神经病学 | 34篇 |
特种医学 | 38篇 |
外科学 | 55篇 |
综合类 | 81篇 |
预防医学 | 61篇 |
眼科学 | 17篇 |
药学 | 78篇 |
中国医学 | 33篇 |
肿瘤学 | 16篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 25篇 |
2020年 | 23篇 |
2019年 | 25篇 |
2018年 | 20篇 |
2017年 | 35篇 |
2016年 | 27篇 |
2015年 | 24篇 |
2014年 | 45篇 |
2013年 | 57篇 |
2012年 | 42篇 |
2011年 | 55篇 |
2010年 | 39篇 |
2009年 | 23篇 |
2008年 | 30篇 |
2007年 | 34篇 |
2006年 | 22篇 |
2005年 | 26篇 |
2004年 | 19篇 |
2003年 | 16篇 |
2002年 | 25篇 |
2001年 | 17篇 |
2000年 | 14篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 1篇 |
排序方式: 共有743条查询结果,搜索用时 15 毫秒
21.
《Archives de pédiatrie》2020,27(6):333-337
Background dataLittle is known about daily walking distance levels, which accounts for approximately 80% of overall physical activity per day, in adolescents with idiopathic scoliosis (AIS).ObjectiveThe aim of this study was to assess the level of walking distance in AIS treated by bracing or not, comparing this activity with that of a control group. We used an original method based on smartphone pedometers for studying walking distance in everyday life.MethodsNineteen AIS patients, aged 14.1 (13–17) years, and 25 asymptomatic patients, aged 12.9 (12–14) years were included prospectively. The 19 AIS cases comprised 9 untreated individuals and 10 with ongoing night brace treatment. The mean walking distance per day as estimated by the pedometer application on smartphones for 2 months was assessed. Weekly sports activities (hours per week) were also reported.ResultsDuring the first month, the mean walking distance was 2.58 ± 0.65 km/day for control patients, 2.31 ± 1.38 km/day for untreated AIS, and 3.65 ± 0.72 km/day for AIS patients treated with a night brace. During the second month, the mean walking distance was 2.60 ± 0.73 km/day for control patients, 2.40 ± 1.41 km/day for untreated AIS, and 3.70 ± 0.72 km/day for AIS patients treated with a night brace. Statistical analysis between groups showed a statistically significant difference with a higher level of daily walking distance in adolescents treated with a night brace compared with other groups.ConclusionThe pedometer on smartphones is a cost-effective and friendly tool to assess adolescents’ level of walking distance. Our results indicate no restriction in terms of daily walking distance between adolescents without scoliosis and those with idiopathic scoliosis.Level of evidenceLevel II. 相似文献
22.
23.
In an effort to assess the effect of ambient temperature on the gross efficiency (Effg) of step exercise 12 subjects performed a modified step test either at —15 °C or 21°C ascending to three different heights (corresponding to light, moderate and heavy work), for 20 min each with a frequency of 18 steps min-1. Heart rate (HR), rectal temperature, skin temperatures and heat flux from skin were continuously measured. Oxygen consumption was measured during the last 5 min of each step height and perceptions of thermal sensation were recorded. The results indicate that, while using conventional clothing adequate in these temperatures, Effg is altered in a contradictory manner. At —15°C Effg increased with increasing work load, whereas at 21°C it decreased when the work load increased. The highest Effg (heavy work at —15°C and light work at 21°C) values are reflected as rather similar rectal temperatures (37.4–37.7°C) and identical mean skin temperatures (32.8 °C) as well as the same (slightly warm) thermal sensation of the legs. At — 15 °C the lowest Effg in light work was probably hue to the need to warm up the muscles. At 21°C, on the contrary, the activation of heat dissipation systems was probably responsible for the lowest Effg in heavy work. 相似文献
24.
25.
Humbert M Beasley R Ayres J Slavin R Hébert J Bousquet J Beeh KM Ramos S Canonica GW Hedgecock S Fox H Blogg M Surrey K 《Allergy》2005,60(3):309-316
BACKGROUND: Patients with severe persistent asthma who are inadequately controlled despite Global Initiative for Asthma (GINA) 2002 step 4 therapy are a challenging population with significant unmet medical need. We determined the effect of omalizumab on clinically significant asthma exacerbations (requiring systemic corticosteroids) in the first omalizumab study to exclusively enrol patients from this difficult-to-treat patient population. METHODS: Following a run-in phase, patients (12-75 years) inadequately controlled despite therapy with high-dose inhaled corticosteroids (ICS) and long-acting beta(2)-agonists (LABA) with reduced lung function and a recent history of clinically significant exacerbations were randomized to receive omalizumab or placebo for 28 weeks in a double-blind, parallel-group, multicentre study. RESULTS: A total of 419 patients were included in the efficacy analyses. The clinically significant asthma exacerbation rate (primary efficacy variable), adjusted for an observed relevant imbalance in history of clinically significant asthma exacerbations, was 0.68 with omalizumab and 0.91 with placebo (26% reduction) during the 28-week treatment phase (P = 0.042). Without adjustment, a similar magnitude of effect was seen (19% reduction), but this did not reach statistical significance. Omalizumab significantly reduced severe asthma exacerbation rate (0.24 vs 0.48, P = 0.002) and emergency visit rate (0.24 vs 0.43, P = 0.038). Omalizumab significantly improved asthma-related quality of life, morning peak expiratory flow and asthma symptom scores. The incidence of adverse events was similar between treatment groups. CONCLUSIONS: In patients with inadequately controlled severe persistent asthma, despite high-dose ICS and LABA therapy, and often additional therapy, omalizumab significantly reduced the rate of clinically significant asthma exacerbations, severe exacerbations and emergency visits. Omalizumab is effective and should be considered as add-on therapy for patients with inadequately controlled severe persistent asthma who have a significant unmet need despite best available therapy. 相似文献
26.
27.
The extracellular presence of the adenine nucleotides ATP and ADP induces calcium mobilization in vascular endothelial cells
(ECs). ATP/ADP concentration at the EC surface is determined by a balance of convective-diffusive transport to and from the
EC surface, hydrolysis by ectonucleotidases at the cell surface, and flow-induced ATP release from ECs. Our previous numerical
simulations in a parallel plate geometry had demonstrated that flow-induced ATP release has a profound effect on nucleotide
concentration at the EC surface. In the present study, we have extended the modeling to probe the impact of flow separation
and recirculation downstream of a backward facing step (BFS) on ATP/ADP concentration at the EC surface. The results show
that for both steady and pulsatile flow over a wide range of wall shear stresses, the ATP + ADP concentration at the EC surface
is considerably lower within the flow recirculation region than in areas of undisturbed flow outside the recirculation zone.
Pulsatile flow also leads to sharp temporal gradients in nucleotide concentration. If confirmed experimentally, the present
findings suggest that disturbed and undisturbed flow may affect EC calcium mobilization differently. Such differences might,
in turn, contribute to the observed endothelial dysfunction in regions of disturbed flow. 相似文献
28.
BackgroundExercise performance depend on the ability of the cardiovascular system to respond to a wide range of metabolic demands and physical exertion.ObjectivesTo investigate the habitual smoking effects in heart rate response and heart rate recovery after step test in athletes.MethodsSeventy-eight physically healthy active athletes (45 non-smokers and 33 smokers) aging 27±8 years old, participated in this study. All participants completed the International Physical Activity Questionnaire and performed the six-minute step test. Cardiovascular parameters such (resting heart rate, peak heart rate, heart rate at 1 min after testing, heart rate recovery, recovery time, blood pressure at rest, and post-testing blood pressure) were recorded.ResultsSmoker-athletes had higher resting heart rate (76 ± 9bpm vs. 72 ± 10bpm, p<0.05), maximum heart rate (154 ± 18bpm vs. 147 ± 17bpm, p<0.05) and recovery time (7min 25sec ± 6min 31sec vs. 4min 21sec ± 4min 30sec, p<0.05) than non-smoker athletes. Scores from the IPAQ were approximately the same (M=7927 ± 10303, M= 6380 ± 4539, p<0.05).ConclusionSmoking was found to affect athletes'' cardiovascular fitness. The change of the athletes'' heart rate recovery and recovery time contributes to the adaptation of cardiovascular function in training requirements. 相似文献
29.
Hirotada Fujiwara Tadashi Narita Hiroshi Hamana Naohiro Horie 《Macromolecular chemistry and physics.》2002,203(16):2357-2368
To develop the radical polyaddition of bisperfluoroisopropenyl esters, the reactions of bis(α‐trifluoromethyl‐β,β‐difluorovinyl) terephthalate [CF2?C(CF3)OCOC6H4COOC(CF3)?CF2] (BFP) with dialkoxydialkylsilane were examined to prepare fluorinated hybrid polymers bearing dialkylsilyl groups in the main chain. Prior to polyaddition, the radical addition reaction of 2‐benzoyloxypentafluoropropene [CF2?C(CF3)OCOC6H5] (BPFP) has been investigated to afford the results that diethoxydimethylsilane (DEOMS) or dimethoxydimethylsilane with BPFP initiated by oxo radical are the best combination for the preparation of polymers. The mechanism of the addition reaction was proposed. Radical polyaddition of BFP with DEOMS initiated by benzoyl peroxide or di‐tert‐butyl peroxide has yielded polymers of up to molecular weight 1 × 106 with rather broad molecular weight distribution. A mechanism for the polyaddition reaction is proposed based on the radical addition reaction between BPFP and DEOMS. The step‐growth polymerization is initiated by hydrogen abstraction of DEOMS to add a perfluoroisopropenyl group, followed by a 1,7‐shift of the radical in the intermediate. The relationship between addition reaction mechanism and polyaddition mechanism was also discussed.
30.
Switching from tenofovir and nucleoside analogue therapy to tenofovir monotherapy in virologically suppressed chronic hepatitis B patients with antiviral resistance 下载免费PDF全文