全文获取类型
收费全文 | 1218篇 |
免费 | 110篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 37篇 |
妇产科学 | 16篇 |
基础医学 | 209篇 |
口腔科学 | 9篇 |
临床医学 | 186篇 |
内科学 | 202篇 |
皮肤病学 | 11篇 |
神经病学 | 178篇 |
特种医学 | 10篇 |
外科学 | 147篇 |
综合类 | 23篇 |
一般理论 | 7篇 |
预防医学 | 122篇 |
眼科学 | 25篇 |
药学 | 61篇 |
中国医学 | 3篇 |
肿瘤学 | 79篇 |
出版年
2023年 | 8篇 |
2022年 | 16篇 |
2021年 | 21篇 |
2020年 | 19篇 |
2019年 | 33篇 |
2018年 | 42篇 |
2017年 | 34篇 |
2016年 | 31篇 |
2015年 | 43篇 |
2014年 | 46篇 |
2013年 | 61篇 |
2012年 | 91篇 |
2011年 | 92篇 |
2010年 | 66篇 |
2009年 | 50篇 |
2008年 | 80篇 |
2007年 | 78篇 |
2006年 | 63篇 |
2005年 | 52篇 |
2004年 | 67篇 |
2003年 | 76篇 |
2002年 | 73篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 19篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1988年 | 3篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1968年 | 3篇 |
1964年 | 3篇 |
1963年 | 3篇 |
1960年 | 6篇 |
1959年 | 2篇 |
1947年 | 2篇 |
1946年 | 2篇 |
排序方式: 共有1333条查询结果,搜索用时 15 毫秒
51.
Gee DG Karlsgodt KH van Erp TG Bearden CE Lieberman MD Belger A Perkins DO Olvet DM Cornblatt BA Constable T Woods SW Addington J Cadenhead KS McGlashan TH Seidman LJ Tsuang MT Walker EF Cannon TD;NAPLS Consortium 《Schizophrenia Research》2012,134(1):1-9
Emotion processing deficits are prominent in schizophrenia and exist prior to the onset of overt psychosis. However, developmental trajectories of neural circuitry subserving emotion regulation and the role that they may play in illness onset have not yet been examined in patients at risk for psychosis. The present study employed a cross-sectional analysis to examine age-related functional activation in amygdala and prefrontal cortex, as well as functional connectivity between these regions, in adolescents at clinical high risk (CHR) for psychosis relative to typically developing adolescents. Participants (n=34) performed an emotion processing fMRI task, including emotion labeling, emotion matching, and non-emotional control conditions. Regression analyses were used to predict activation in the amygdala and ventrolateral prefrontal cortex (vlPFC) based on age, group, sex, and the interaction of age by group. CHR adolescents exhibited altered age-related variation in amygdala and vlPFC activation, relative to controls. Controls displayed decreased amygdala and increased vlPFC activation with age, while patients exhibited the opposite pattern (increased amygdala and decreased vlPFC activation), suggesting a failure of prefrontal cortex to regulate amygdala reactivity. Moreover, a psychophysiological interaction analysis revealed decreased amygdala-prefrontal functional connectivity among CHR adolescents, consistent with disrupted brain connectivity as a vulnerability factor in schizophrenia. These results suggest that the at-risk syndrome is marked by abnormal development and functional connectivity of neural systems subserving emotion regulation. Longitudinal data are needed to confirm aberrant developmental trajectories intra-individually and to examine whether these abnormalities are predictive of conversion to psychosis, and of later deficits in socioemotional functioning. 相似文献
52.
Nadine Lehnen Thyra Langhagen Florian Heinen Doreen Huppert Thomas Brandt Klaus Jahn 《Developmental medicine and child neurology》2015,57(4):393-396
Vestibular paroxysmia due to neurovascular compression is a syndrome consisting of frequent short episodes of vertigo in adults that can be easily treated. Here we describe the initial presentation and follow‐up of three children (one female, 12y; two males, 8y and 9y) who experienced typical, brief, vertiginous attacks several times a day. Nystagmus was observed during the episodes. Cranial magnetic resonance imaging revealed arterial compression of the eighth cranial nerve. The attacks ceased after administration of low‐dose carbamazepine (2–4mg/kg daily). Vestibular paroxysmia must be considered in the differential diagnosis of children with brief vertiginous episodes. 相似文献
53.
Reliability of an fMRI paradigm for emotional processing in a multisite longitudinal study 下载免费PDF全文
Dylan G. Gee Sarah C. McEwen Jennifer K. Forsyth Kristen M. Haut Carrie E. Bearden Jean Addington Bradley Goodyear Kristin S. Cadenhead Heline Mirzakhanian Barbara A. Cornblatt Doreen Olvet Daniel H. Mathalon Thomas H. McGlashan Diana O. Perkins Aysenil Belger Larry J. Seidman Heidi Thermenos Ming T. Tsuang Theo G.M. van Erp Elaine F. Walker Stephan Hamann Scott W. Woods Todd Constable Tyrone D. Cannon 《Human brain mapping》2015,36(7):2558-2579
Multisite neuroimaging studies can facilitate the investigation of brain‐related changes in many contexts, including patient groups that are relatively rare in the general population. Though multisite studies have characterized the reliability of brain activation during working memory and motor functional magnetic resonance imaging tasks, emotion processing tasks, pertinent to many clinical populations, remain less explored. A traveling participants study was conducted with eight healthy volunteers scanned twice on consecutive days at each of the eight North American Longitudinal Prodrome Study sites. Tests derived from generalizability theory showed excellent reliability in the amygdala ( = 0.82), inferior frontal gyrus (IFG; = 0.83), anterior cingulate cortex (ACC; = 0.76), insula ( = 0.85), and fusiform gyrus ( = 0.91) for maximum activation and fair to excellent reliability in the amygdala ( = 0.44), IFG ( = 0.48), ACC ( = 0.55), insula ( = 0.42), and fusiform gyrus ( = 0.83) for mean activation across sites and test days. For the amygdala, habituation ( = 0.71) was more stable than mean activation. In a second investigation, data from 111 healthy individuals across sites were aggregated in a voxelwise, quantitative meta‐analysis. When compared with a mixed effects model controlling for site, both approaches identified robust activation in regions consistent with expected results based on prior single‐site research. Overall, regions central to emotion processing showed strong reliability in the traveling participants study and robust activation in the aggregation study. These results support the reliability of blood oxygen level‐dependent signal in emotion processing areas across different sites and scanners and may inform future efforts to increase efficiency and enhance knowledge of rare conditions in the population through multisite neuroimaging paradigms. Hum Brain Mapp 36:2558–2579, 2015. © 2015 Wiley Periodicals, Inc . 相似文献
54.
Decline in episodic memory, the encoding and retrieval of autobiographical events, is a hallmark of normal cognitive aging. Although the primary causes of this decline remain elusive, event-related brain potential (ERP) studies have contributed to an understanding of age-related episodic memory failure. These data reveal that, although the retrieval-based episodic memory (EM) effect does not differ dramatically between young and older adults, the acquisition-related data suggest a decline in episodic encoding (i.e., semantic elaboration) with increasing age. We conclude that, at the current state of knowledge, encoding deficiencies are more important than retrieval deficits in understanding the causes of episodic memory decline in the older adult. 相似文献
55.
56.
Background and Purpose . Surgical intervention for vulvar cancer and vulvar intraepithelial neoplasia causes mutilation of the genital area and can impose significant bladder, bowel and sexual dysfunction. This case report outlines how conservative interventions such as pelvic floor muscle training (PFMT) may reduce the long‐term morbidities of such dysfunction. Method . The patient underwent 16 weeks of PFMT in conjunction with advice on fluid intake and bladder training. Results . An increase in pelvic floor muscle strength and endurance were recorded. Improved bladder control as demonstrated by a reduction in frequency of voiding (from 15 to 7 per 24 hours), and number of pads used (from 6 to 3 per 24 hours) was evident. The impact of urinary incontinence on everyday life was much less at the end of the treatment period as measured by the Incontinence Impact Questionnaire with a change in score from 21 (maximum impact) to 10. Conclusions . These positive results indicate that further research is needed to investigate the effect of PFMT on bladder function following such surgery. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
57.
58.
Kessler RC Merikangas KR Berglund P Eaton WW Koretz DS Walters EE 《Archives of general psychiatry》2003,60(11):1117-1122
BACKGROUND: High prevalence estimates in epidemiological surveys have led to concerns that the DSM system is overly inclusive and that mild cases should be excluded from future DSM editions. OBJECTIVE: To demonstrate that the DSM-III-R disorders in the baseline National Comorbidity Survey (NCS) can be placed on a severity gradient that has a dose-response relationship with outcomes assessed a decade later in the NCS follow-up survey (NCS-2) and that no inflection point exists at the mild severity level. METHODS: The NCS was a nationally representative household survey of DSM-III-R disorders in the 3-year time span 1990-1992. The NCS-2 is a follow-up survey of 4375 NCS respondents (76.6% conditional response rate) reinterviewed in 2000 through 2002. The NCS-2 outcomes include hospitalization for mental health or substance disorders, work disability due to these disorders, suicide attempts, and serious mental illness. RESULTS: Twelve-month NCS/DSM-III-R disorders were disaggregated into 3.2% severe, 3.2% serious, 8.7% moderate, and 16.0% mild case categories. All 4 case categories were associated with statistically significantly (P<.05, 2-sided tests) elevated risk of the NCS-2 outcomes compared with baseline noncases, with odds ratios of any outcome ranging monotonically from 2.4 (95% confidence interval, 1.6-3.4) to 15.1 (95% confidence interval, 10.0-22.9) for mild to severe cases. Odds ratios comparing mild to moderate cases were generally nonsignificant. CONCLUSIONS: There is a graded relationship between mental illness severity and later clinical outcomes. Retention of mild cases in the DSM is important to represent the fact that mental disorders (like physical disorders) vary in severity. Decisions about treating mild cases should be based on cost-effectiveness not current severity. Cost-effectiveness analysis should include recognition that treatment of mild cases might prevent a substantial proportion of future serious cases. 相似文献
59.
60.
Kennes J Rosenbaum P Hanna SE Walter S Russell D Raina P Bartlett D Galuppi B 《Developmental medicine and child neurology》2002,44(4):240-247
In this study parents' systematic accounts of the health status of 408 school-aged children with cerebral palsy (CP) are reported (221 males, 187 females; mean age 8 years 5 months, SD 1 year 11 months; range 5 to 13 years), as are relations between severity of functional motor impairment and eight functional health status domains. Data were collected as part of a longitudinal study of the motor development of a population-based, stratified, random sample of children with CP from across Ontario, Canada. The Gross Motor Function Classification System (GMFCS) was used to classify severity of CP and functional health status was described with the eight-level Health Utilities Index-Mark 3. Rates of functional limitations in Mobility, Dexterity, Speech, and Vision were statistically significantly associated with GMFCS levels (all p<0.01), with correlation values (tau-b) of 0.82, 0.58, 0.46, and 0.36, respectively. Functional limitations in hearing (tau-b=0.16; p=0.04) and cognition (tau-b=0.27; p<0.01) were both statistically significantly associated with GMFCS levels, though correlations were low. Neither emotion (tau-b=0.03; p=0.24) nor pain (tau-b=0.07; p=0.37) was associated with degree of functional limitation as described by the GMFCS. Clinical and epidemiological implications of findings are discussed. 相似文献