全文获取类型
收费全文 | 7369篇 |
免费 | 888篇 |
国内免费 | 127篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 109篇 |
妇产科学 | 60篇 |
基础医学 | 734篇 |
口腔科学 | 67篇 |
临床医学 | 908篇 |
内科学 | 741篇 |
皮肤病学 | 29篇 |
神经病学 | 1613篇 |
特种医学 | 485篇 |
外科学 | 356篇 |
综合类 | 1138篇 |
一般理论 | 2篇 |
预防医学 | 740篇 |
眼科学 | 62篇 |
药学 | 677篇 |
8篇 | |
中国医学 | 479篇 |
肿瘤学 | 134篇 |
出版年
2024年 | 12篇 |
2023年 | 112篇 |
2022年 | 180篇 |
2021年 | 403篇 |
2020年 | 387篇 |
2019年 | 346篇 |
2018年 | 309篇 |
2017年 | 336篇 |
2016年 | 317篇 |
2015年 | 355篇 |
2014年 | 592篇 |
2013年 | 531篇 |
2012年 | 453篇 |
2011年 | 482篇 |
2010年 | 356篇 |
2009年 | 362篇 |
2008年 | 309篇 |
2007年 | 307篇 |
2006年 | 296篇 |
2005年 | 247篇 |
2004年 | 199篇 |
2003年 | 194篇 |
2002年 | 158篇 |
2001年 | 118篇 |
2000年 | 91篇 |
1999年 | 93篇 |
1998年 | 60篇 |
1997年 | 71篇 |
1996年 | 44篇 |
1995年 | 55篇 |
1994年 | 59篇 |
1993年 | 53篇 |
1992年 | 37篇 |
1991年 | 46篇 |
1990年 | 56篇 |
1989年 | 36篇 |
1988年 | 30篇 |
1987年 | 27篇 |
1986年 | 29篇 |
1985年 | 37篇 |
1984年 | 37篇 |
1983年 | 15篇 |
1982年 | 22篇 |
1981年 | 17篇 |
1980年 | 25篇 |
1979年 | 14篇 |
1978年 | 16篇 |
1977年 | 22篇 |
1975年 | 8篇 |
1974年 | 7篇 |
排序方式: 共有8384条查询结果,搜索用时 15 毫秒
71.
Organ spectrophotometry has been applied to analyze cytochrome redox changes in brain slice preparations. An interface-chamber method for maintaining metabolism of brain slice tissues was devised to reduce noise on recording traces of spectrophotometric signals, and then used for continuous monitoring and simultaneous recording of electrical and optical signals from brain slices. With this method, the noise level during the recording of redox states of cytochromes was decreased to 0.0004 A unit. 相似文献
72.
Martin Griebe Michael Daffertshofer Mark Stroick Magdalena Syren Parviz Ahmad-Nejad Michael Neumaier Juergen Backhaus Michael G. Hennerici Marc Fatar 《Neuroscience letters》2007
Biological markers play an evolving role in the diagnosis of Alzheimer disease (AD). We compare conventional measurements of cerebrospinal fluid (CSF) tau and β-amyloid1–42 proteins to a novel approach – Fourier transformed infrared (FT-IR) spectroscopy – a simple technique derived from chemical and physical sciences that characterizes intramolecular bonds. For automatic diagnostic analysis, we developed an artificial neural network (ANN). We examined 71 patients with a clinical diagnosis of AD and 66 controls. β-Amyloid1–42 was decreased (sensitivity 80% and specificity 78%); tau was elevated (sensitivity 76% and specificity 88%) in CSF of AD patients. The combined tau/β-amyloid1–42 quotient was able to distinguish healthy from diseased subjects with 99% sensitivity and 86% specificity. The ANN could separate FT-IR spectroscopy data with 88.5% sensitivity and 80% specificity. FT-IR spectroscopy proved to be cost-effective and simple to perform. Diagnostic sensitivity and specificity is in the range of CSF tau and β-amyloid1–42 protein analysis. Larger sample numbers for ANN training and validation could increase diagnostic accuracy and thus prove to be a useful screening tool. 相似文献
73.
A finite element model of the steady state temperature distribution in the human torso is developed. The torso is approximated by a circular cylinder of core surrounded by a layer of muscle and insulating layers of fat and skin. The model is simplified by neglecting longitudinal heat flow. The region occupied by a circular cross-section of the torso is discretized into a mesh of triangles and the boundary of the torso, that is, the skin surface, is consequently approximated by a polygon. The elliptic partial differential equation governing the steady state temperature distribution, together with the associated boundary conditions, are expressed in equivalent variational form. Linear basis functions are used and the resulting integral is minimized over the region bounded by the approximating polygon. Results for two numerical experiments are determined by solving systems of linear equations. 相似文献
74.
R.D. Myers H.S. Swartzwelder J.M. Peinado T.F. Lee J.R. Hepler D.M. Denbow J.M.R. Ferrer 《Brain research bulletin》1986,17(4):583-597
The purpose of this investigation was to determine the functional relationship between putative satiety peptides and endogenous norepinephrine (NE) activity in the hypothalamus. Permanent guide cannulae for push-pull perfusion were implanted stereotaxically in Sprague-Dawley rats so as to rest above the medial or lateral hypothalamus (LH). Post-operatively, the animals were either satiated with food and water, both available ad lib, or fasted for 18-22 hr prior to an experiment. To perfuse a site in the LH, paraventricular (PVN) or ventromedial nucleus (VMN), a concentric 29-23 ga push-pull cannula system was lowered to a pre-determined site, in most cases after catecholamine stores had been pre-labeled with [3H]-NE. During control tests, an artificial CSF was perfused at a rate of 20-25 microliter/min for 5-8 min with a 5 min interval between each sample. The addition of cholecystokinin (CCK) in a concentration of 2.0-6.0 ng/microliter to the CSF perfused in PVN or VMN of the satiated rat enhanced the efflux of NE; however, in the fasted animal CCK often suppressed the catecholamine's release. Perfused in the LH, CCK exerted opposite effects, typically augmenting NE output when the rat was fasted but not affecting the amine's activity during the sated condition. Proglumide (1.2 micrograms/microliter) attenuated CCK's effect in releasing NE when the antagonist was perfused in the PVN of the satiated rat. Similar experiments in which neurotensin (NT) was perfused in the LH, PVN and VMN revealed virtually the same inverse effects on NE release in the fasted and satiated rat, which again were anatomically specific. Finally, insulin and 2-deoxy-D-glucose (2-DG) exerted similar state-dependent effects on the release of NE within LH and PVN. Overall, the results suggest that CCK or other neuroactive peptide could serve as a "neuromodulator" of the pre-synaptic release of NE within classical hypothalamic structures which are thought to underlie both hunger and satiety. The state-dependent nature of the peptides' activity on the noradrenergic feeding mechanism implies that these substances constitute a pivotal portion of the profile of factors which impinge functionally upon the hypothalamic neurons responsible for the feeding response and its cessation. 相似文献
75.
目的 探讨渐进性肌肉放松训练配合心理干预对艾滋病患者服药依从性及心理状态的影响。方法 选择2017年8月—2020年8月于本院就诊的68例艾滋病患者,按随机数字表法分为对照组和观察组,每组34例。对照组实施常规护理干预,观察组在此基础上实施渐进性肌肉放松训练配合心理干预,比较两组服药依从性及医院焦虑抑郁量表(HospitalAnxietyand Depresseo Scale,HAD)评分。结果 观察组服药总依从率为97.06%,高于对照组的70.59%,(χ2=8.785,P=0.003);观察组干预2周后焦虑评分为(14.35±1.67)分、抑郁评分为(13.98±1.38)分,均低于对照组的(15.63±1.59)分、(15.08±1.27)分,(t=3.237、3.420,P=0.002、0.001)。结论 渐进性肌肉放松训练配合心理干预应用于艾滋病患者,能够提高患者服药依从性,改善患者心理状态。 相似文献
76.
目的分析综合护理对促进小儿手足口病病情恢复的效果观察。方法手足口病患儿作为本次研究的主要对象,总例数(选取人数)200例,患者收取时间在2018年10月-2019年10月,研究对象200例使用电脑随机分配方式分为两组,其中100例作为观察组(实施综合护理)、100例作为对照组(实施常规护理),将两组的口腔糜烂愈合时间、住院时间、皮疹消退时间、家属焦虑评分和抑郁评分进行比较。结果观察组手足口病患儿护理后口腔糜烂愈合时间、住院时间、皮疹消退时间显著优于对照组(P<0.05)。观察组患儿家属护理后焦虑(46.25±1.64)分、抑郁(52.03±1.21)分均低于对照组(P<0.05)。结论综合护理在小儿手足口病病情恢复中具有良好的护理效果。 相似文献
77.
Katharina Voigt Emily Giddens Romana Stark Emma Frisch Neda Moskovsky Naomi Kakoschke Julie C. Stout Mark A. Bellgrove Zane B. Andrews Antonio Verdejo-Garcia 《Nutrients》2021,13(6)
Food homeostatic states (hunger and satiety) influence the cognitive systems regulating impulsive responses, but the direction and specific mechanisms involved in this effect remain elusive. We examined how fasting, and satiety, affect cognitive mechanisms underpinning disinhibition using a novel framework and a gamified test-battery. Thirty-four participants completed the test-battery measuring three cognitive facets of disinhibition: attentional control, information gathering and monitoring of feedback, across two experimental sessions: one after overnight fasting and another after a standardised meal. Homeostatic state was assessed using subjective self-reports and biological markers (i.e., blood-derived liver-expressed antimicrobial protein 2 (LEAP-2), insulin and leptin). We found that participants who experienced greater subjective hunger during the satiety session were more impulsive in the information gathering task; results were not confounded by changes in mood or anxiety. Homeostatic state did not significantly influence disinhibition mechanisms linked to attentional control or feedback monitoring. However, we found a significant interaction between homeostatic state and LEAP-2 on attentional control, with higher LEAP-2 associated with faster reaction times in the fasted condition only. Our findings indicate lingering hunger after eating increases impulsive behaviour via reduced information gathering. These findings identify a novel mechanism that may underpin the tendency to overeat and/or engage in broader impulsive behaviours. 相似文献
78.
ObjectivesA number of studies have shown an association between smoking habit and quality of life, but these have mainly involved cross-sectional data. This study takes advantage of longitudinal panel data to estimate the effect of the transition from “smoker” to “ex-smoker” status (smoking cessation) on health-related quality of life (HRQoL), measured by SF-36, in an Australian general population sample.MethodsPanel data from 13 waves (2001-2013) of a nationally representative longitudinal survey of Household Income and Labour Dynamics of Australia (HILDA) were used; 1858 respondents (5% of total HILDA sample) who experienced only 1 cessation event in their HILDA life were selected. HRQoL trajectories elicited by SF-36 (0-100 scale, worst to best health) were modeled before and after cessation events using a piecewise (segmented) 2-way fixed-effect linear regression, adopted to capture within-person differences. This enabled measurement of changes of regression slopes and intercept while controlling time-invariant characteristics (eg, country of birth, gender) and time-varying changes in health status.ResultsAnnual pre-post intervention improvements were estimated for the following dimensions: role physical 0.65 (95% CI 0.62-1.24), bodily pain 0.48 (95% CI 0.10-0.86), general health 0.55 (95% CI 0.2-0.9), and the physical component summary score 0.22 (95% CI 0.01-0.04). Immediate effects (discontinuity at the time of cessation) of smoking cessation existed for bodily pain –1.5 (95% CI –2.52 to –0.40) and general health 1.82 (95% CI 1.01-2.62). The effects for mental health domains were not significant.ConclusionsAdjusting for all unmeasured time-invariant confounders and controlling the effect of time, this study revealed the varied effects of smoking cessation on HRQoL; it has positive effect on physical and general health but nonsignificant effect on mental aspects. Preference-based utility measures based on SF-6D capture changes that can be measured in several of the domains of the SF-36. 相似文献
79.
Paul Peter Schneider 《Health economics》2021,30(1):104-112
In economic evaluations of health technologies, health outcomes are commonly measured in terms of quality‐adjusted life years (QALYs). QALYs are the product of time and health‐related quality of life. Health‐related quality of life, in turn, is determined by a social tariff, which is supposed to reflect the public's preference over health states. This study argues that, because of the tariff's role in the societal decision‐making process, it should not be understood as merely an operational (statistical) definition of health, but as a major instrument of democratic participation. I outline what implications this might have for both the method used to aggregate individual preferences, and the set of individuals whose preferences should count. Alternative tariff specifications and decision rules are explored, and future research directions are proposed. 相似文献
80.
溃疡性结肠炎患者的心理健康状况及个性特征 总被引:13,自引:2,他引:11
目的 了解溃疡性结肠炎(UC)患者的心理健康状况及个性特征。方法 采用症状自评量表(SCL-90)、Zung焦虑自评量表(SAS)、抑郁自评量表(SDS)及卡特尔16项人格测评问卷(16-PF)调查了46例UC患者并与健康者对照。结果 UC患者SCL-90总分、阳性项目数,阳性症状均分、躯体化、焦虑、恐怖以及SAS、SDS得分均升高。16PF结果:O、Q4因子分及次级人格因子中X1分升高而C、F、Y1分均下降。UC病人抑郁发生率32.6%明显高于健康者。结论 UC病人存在明显的心理健康障碍,主要表现为躯体化、焦虑、抑郁、恐怖。同时UC患者存在不良的人格特征:表现为个性同倾、敏感、固执、情绪稳定性差。 相似文献