全文获取类型
收费全文 | 14802篇 |
免费 | 959篇 |
国内免费 | 37篇 |
专业分类
耳鼻咽喉 | 126篇 |
儿科学 | 607篇 |
妇产科学 | 462篇 |
基础医学 | 2136篇 |
口腔科学 | 256篇 |
临床医学 | 2055篇 |
内科学 | 2386篇 |
皮肤病学 | 284篇 |
神经病学 | 1656篇 |
特种医学 | 266篇 |
外科学 | 1011篇 |
综合类 | 156篇 |
现状与发展 | 1篇 |
一般理论 | 37篇 |
预防医学 | 2193篇 |
眼科学 | 208篇 |
药学 | 810篇 |
中国医学 | 11篇 |
肿瘤学 | 1137篇 |
出版年
2023年 | 144篇 |
2022年 | 181篇 |
2021年 | 342篇 |
2020年 | 253篇 |
2019年 | 371篇 |
2018年 | 372篇 |
2017年 | 336篇 |
2016年 | 293篇 |
2015年 | 355篇 |
2014年 | 508篇 |
2013年 | 799篇 |
2012年 | 1103篇 |
2011年 | 1147篇 |
2010年 | 582篇 |
2009年 | 544篇 |
2008年 | 992篇 |
2007年 | 974篇 |
2006年 | 1009篇 |
2005年 | 997篇 |
2004年 | 905篇 |
2003年 | 834篇 |
2002年 | 826篇 |
2001年 | 106篇 |
2000年 | 62篇 |
1999年 | 107篇 |
1998年 | 189篇 |
1997年 | 149篇 |
1996年 | 106篇 |
1995年 | 110篇 |
1994年 | 92篇 |
1993年 | 77篇 |
1992年 | 75篇 |
1991年 | 48篇 |
1990年 | 49篇 |
1989年 | 39篇 |
1988年 | 36篇 |
1987年 | 24篇 |
1986年 | 46篇 |
1985年 | 43篇 |
1984年 | 53篇 |
1983年 | 65篇 |
1982年 | 82篇 |
1981年 | 53篇 |
1980年 | 50篇 |
1979年 | 31篇 |
1978年 | 33篇 |
1977年 | 21篇 |
1976年 | 19篇 |
1974年 | 22篇 |
1972年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Variability in behavior is often put in an unfavorable light as a marker of lack of skill. Here, we provide evidence that increased variability during preferred patterns of coordination is associated with higher flexibility in adopting new patterns. Twelve right-handed subjects performed cyclical bimanual flexion and extension patterns with four homologous and six heterologous joint combinations involving shoulder, elbow, wrist, and finger movements. Preferred (isofrequency) as well as less preferred (multifrequency) coordination patterns were studied. The findings revealed less accurate and less stable 1:1 coordination patterns during heterologous as compared to homologous limb segment combinations. Conversely, coordination patterns with a 2:1 frequency ratio were performed more accurately and more consistently during heterologous as compared to homologous conditions. Accordingly, a lower degree of coupling between effectors during performance of preferred coordination patterns was associated with more successful performance of less familiar patterns. This suggests that variability may promote the creative exploration of new performance modes. 相似文献
992.
Psychiatric advance directives (PADs) inform treatment during periods of compromised decision-making. We report consumer desire and need for support to create PADs among 106 adult outpatients with severe and persistent mental illness. PADs were completed using computer software and flexible peer support. All participants were able to complete PADs. However, nearly all participants needed support using the software, or clarification of PAD information. Types of support needed may vary depending on PAD creation methods. While one-third of participants wanted support from case managers to complete PADs, the appropriate level of clinician support is not clear-cut, and should be at consumers' discretion. 相似文献
993.
Vloeberghs E Van Dam D Engelborghs S Nagels G Staufenbiel M De Deyn PP 《The European journal of neuroscience》2004,20(10):2757-2766
Over the past decade, clinical Alzheimer's disease research has been challenged with an increased interest in noncognitive symptomatology, commonly referred to as behavioural and psychological signs and symptoms of dementia (BPSD). In accordance, major attention is being paid to behavioural alterations in the phenotyping of transgenic mouse models. Besides an age-dependent decline of cognitive functions, the APP23 model was previously shown to exhibit cage activity disturbances, reminiscent of diurnal rhythm disturbances in Alzheimer patients. To further scrutinize these observations, circadian patterns of horizontal locomotor activity were assessed in 3-, 6- and 12-month-old APP23 mice and wild-type littermates in a test paradigm continuously recording cage activity over a period ranging from 1 to 3 days. At the age of 3 months, APP23 profiles resembled the wild-type pattern to a large extent, although minor differences were already noticeable. Six-month-old APP23 mice displayed an altered activity profile with a first indication of increased activity during the second half of the active phase, reminiscent of sundowning behaviour in Alzheimer patients. This bimodal overnight activity pattern became even more evident at the age of 12 months. The APP23 model was therefore shown to display an age-dependent development of cage activity disturbances and sundowning-like behaviour. A comparison is made with actigraphic recordings of human Alzheimer patients exhibiting sundowning behaviour. This first report of diurnal rhythm disturbances and sundowning-like phenomena in a transgenic mouse model greatly adds to the validity of the APP23 model. 相似文献
994.
Griffey M Bible E Vogler C Levy B Gupta P Cooper J Sands MS 《Neurobiology of disease》2004,16(2):360-369
Infantile neuronal ceroid lipofuscinosis (INCL) is the earliest onset form of a class of inherited neurodegenerative disease called Batten disease. INCL is caused by a deficiency in the lysosomal enzyme palmitoyl protein thioesterase-1 (PPT1). Autofluorescent storage material accumulates in virtually all tissues in INCL patients, including the brain, and leads to widespread neuronal loss and cortical atrophy. To determine the efficacy of viral-mediated gene therapy, we injected a recombinant adeno-associated virus 2 vector encoding human PPT1 (rAAV-PPT1) intracranially (I.C.) into a murine model of INCL. INCL mice given four I.C. injections of rAAV-PPT1 as newborns exhibited PPT1 activity near the injection sites and decreased secondary elevations of another lysosomal enzyme. In addition, storage material was decreased in cortical, hippocampal, and cerebellar neurons, and brain weights and cortical thicknesses were increased. These data demonstrate that an adeno-associated virus 2 (AAV2)-mediated gene therapy approach may provide some therapeutic benefit for INCL. 相似文献
995.
In rehabilitation for hemiparesis, one of the goals of an occupational therapist is to practice upper extremity tasks with the recovering individual. The practice is intended to strengthen muscles and refine movements. It also provides examples for the recovering body and brain as they attempt to reestablish the now delicate cognitive and neural connections mediating voluntary behavior. However, the paresis significantly limits the movement sequence possibilities that may be physically practiced. We outline a method for using simulation of movement, which is intended to provide a means for experiencing a range of smooth and controlled movements completed by a paretic limb. The simulation provides a compelling perceptual experience of bilateral motion beyond the current capabilities of the affected limb. The benefits of this technique after a 3-week course of the simulation practice are exemplified by the presented case study that reveals improved function as demonstrated by increases in Fugl-Meyer scores and faster movement speeds as demonstrated by decreased movement times for the Jebsen test of hand function. 相似文献
996.
Employment outcome for individuals with psychiatric disabilities has been a focus of empirical research over the past decade or so. The purpose of this paper is to review recent literature on the association between demographic and diagnostic factors and employment outcome, and to conduct meta analyses of the results of studies that report the association between these variables. Seventeen studies were included in these meta analyses. Results of the meta analyses tended to corroborate most of the significant findings found in the literature review. The authors review some of the issues for the meta-analyst interested in synthesizing research findings on employment outcome, including the challenges and limitations encountered in the published research currently available. 相似文献
997.
The nature and determinants of neuropsychological functioning in late-life depression 总被引:6,自引:0,他引:6
Butters MA Whyte EM Nebes RD Begley AE Dew MA Mulsant BH Zmuda MD Bhalla R Meltzer CC Pollock BG Reynolds CF Becker JT 《Archives of general psychiatry》2004,61(6):587-595
CONTEXT: Cognitive impairment in late-life depression (LLD) is highly prevalent, disabling, poorly understood, and likely related to long-term outcome. OBJECTIVES: To determine the characteristics and determinants of neuropsychological functioning LLD. DESIGN: Cross-sectional study of groups of LLD patients and control subjects. SETTING: Outpatient, university-based depression research clinic. PARTICIPANTS: One hundred patients without dementia 60 years and older who met DSM-IV criteria for current episode of unipolar major depression (nonpsychotic) and 40 nondepressed, age- and education-equated control subjects. MAIN OUTCOME MEASURES: A comprehensive neuropsychological battery. RESULTS: Relative to control subjects, LLD patients performed poorer in all cognitive domains. More than half exhibited significant impairment (performance below the 10th percentile of the control group). Information processing speed and visuospatial and executive abilities were the most broadly and frequently impaired. The neuropsychological impairments were mediated almost entirely by slowed information processing (beta =.45-.80). Education (beta =.32) and ventricular atrophy (beta =.28) made additional modest contributions to variance in measures of language ability. Medical and vascular disease burden, apolipoprotein E genotype, and serum anticholinergicity did not contribute to variance in any cognitive domain. CONCLUSIONS: Late-life depression is characterized by slowed information processing, which affects all realms of cognition. This supports the concept that frontostriatal dysfunction plays a key role in LLD. The putative role of some risk factors was validated (eg, advanced age, low education, depression severity), whereas others were not (eg, medical burden, age at onset of first depressive episode). Further studies of neuropsychological functioning in remitted LLD patients are needed to parse episode-related and persistent factors and to relate them to underlying neural dysfunction. 相似文献
998.
The present study investigated the effect of H-Try-d-Ala-Phe-Glu-Val-Gly-NH2 deltorphin-II, a selective delta-2 agonist, and [d-Pen(2),d-Pen(5)]enkephalin, a selective delta-1 agonist, on body temperature in the rat. Microinjected into the preoptic anterior hypothalamus (POAH), deltorphin-II (0.1-1 microg) produced an immediate dose-related hyperthermia following injection. Injection of the delta-2 antagonist naltriben into the preoptic anterior hypothalamus (1 microg, 30 min prior to deltorphin-II) significantly attenuated the deltorphin-II-induced hyperthermia. Microinjection of [d-Pen(2),d-Pen(5)]enkephalin into the POAH (0.1-3 microg) did not affect Tb. The data demonstrate that delta-2 receptors are involved in the mediation of Tb effects, and deltorphin-II exerts its action directly on thermosensitive cells of the preoptic anterior hypothalamus. Delta-1 opioid receptors do not appear to be involved in the control of body temperature. 相似文献
999.
Dennehy EB Suppes T John Rush A Lynn Crismon M Witte B Webster J 《Journal of psychiatric research》2004,38(3):285-294
The adoption of treatment guidelines for complex psychiatric illness is increasing. Treatment decisions in psychiatry depend on a number of variables, including severity of symptoms, past treatment history, patient preferences, medication tolerability, and clinical response. While patient outcomes may be improved by the use of treatment guidelines, there is no agreed upon standard by which to assess the degree to which clinician behavior corresponds to those recommendations. This report presents a method to assess clinician adherence to the complex multidimensional treatment guideline for bipolar disorder utilized in the Texas Medication Algorithm Project. The steps involved in the development of this system are presented, including the reliance on standardized documentation, defining core variables of interest, selecting criteria for operationalization of those variables, and computerization of the assessment of adherence. The computerized assessment represents an improvement over other assessment methods, which have relied on laborious and costly chart reviews to extract clinical information and to analyze provider behavior. However, it is limited by the specificity of decisions that guided the adherence scoring process. Preliminary findings using this system with 2035 clinical visits conducted for the bipolar disorder module of TMAP Phase 3 are presented. These data indicate that this system of guideline adherence monitoring is feasible. 相似文献
1000.