全文获取类型
收费全文 | 16027篇 |
免费 | 1208篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 123篇 |
儿科学 | 388篇 |
妇产科学 | 376篇 |
基础医学 | 2541篇 |
口腔科学 | 243篇 |
临床医学 | 1636篇 |
内科学 | 3558篇 |
皮肤病学 | 292篇 |
神经病学 | 1454篇 |
特种医学 | 584篇 |
外国民族医学 | 4篇 |
外科学 | 2290篇 |
综合类 | 188篇 |
一般理论 | 4篇 |
预防医学 | 1201篇 |
眼科学 | 263篇 |
药学 | 944篇 |
中国医学 | 8篇 |
肿瘤学 | 1195篇 |
出版年
2021年 | 192篇 |
2020年 | 115篇 |
2019年 | 216篇 |
2018年 | 261篇 |
2017年 | 172篇 |
2016年 | 176篇 |
2015年 | 248篇 |
2014年 | 349篇 |
2013年 | 499篇 |
2012年 | 689篇 |
2011年 | 695篇 |
2010年 | 384篇 |
2009年 | 433篇 |
2008年 | 699篇 |
2007年 | 705篇 |
2006年 | 712篇 |
2005年 | 636篇 |
2004年 | 636篇 |
2003年 | 635篇 |
2002年 | 608篇 |
2001年 | 563篇 |
2000年 | 606篇 |
1999年 | 465篇 |
1998年 | 181篇 |
1997年 | 166篇 |
1996年 | 162篇 |
1995年 | 129篇 |
1994年 | 149篇 |
1993年 | 120篇 |
1992年 | 373篇 |
1991年 | 345篇 |
1990年 | 362篇 |
1989年 | 335篇 |
1988年 | 338篇 |
1987年 | 320篇 |
1986年 | 332篇 |
1985年 | 292篇 |
1984年 | 219篇 |
1983年 | 177篇 |
1982年 | 113篇 |
1981年 | 114篇 |
1979年 | 164篇 |
1978年 | 162篇 |
1977年 | 143篇 |
1975年 | 158篇 |
1974年 | 181篇 |
1973年 | 136篇 |
1972年 | 137篇 |
1971年 | 139篇 |
1970年 | 121篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
RamachandranNair R Sharma R Weiss SK Otsubo H Cortez MA 《The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques》2005,32(4):518-523
OBJECTIVE: This study was designed to determine the prevalence of rhythmic coma patterns in comatose children and to ascertain the prognostic significance of reactive rhythmic coma patterns. METHODS: We retrospectively analyzed and classified electroencephalogram (EEGs) in comatose children between two months and 18 years of age during the period 1996 - 2003 according to modified Young's classification. Outcome at one-year was scored according to the Paediatric Cerebral and Overall Performance Category Scale. Outcomes were compared using Fisher's exact test and Mann-Whitney test. RESULTS: Analysis of 63 electroencephalogram (EEG) records in 38 patients showed rhythmic patterns in 19 records (30.2%; 9 alpha, 4 spindle, 4 theta and 2 beta coma patterns, total number of children = 14). Aetiology and outcome of alpha coma patterns and other rhythmic coma patterns were similar. In five children, one type of rhythmic pattern changed to another. Records with reactive rhythmic coma 66.7% (6/9), were associated with favourable outcome. Sixty percent of the records (6/10 records in seven children) with non-reactive pattern were associated with unfavourable outcome. This clinically significant difference did not reach statistical significance (lower Paediatric Cerebral and Overall Performance Category Scale score p= 0.14; favourable outcome p=0. 19). CONCLUSION: Rhythmic coma patterns in comatose children are not uncommon. Aetiology, reactivity and outcome of individual patterns are similar and thus make the rhythmic coma patterns distinct EEG signatures in comatose children. There was a clinically significant better outcome with reactive rhythmic coma patterns. 相似文献
992.
Recurrent intractable seizures in children with cortical dysplasia adjacent to dysembryoplastic neuroepithelial tumor 总被引:7,自引:0,他引:7
Sakuta R Otsubo H Nolan MA Weiss SK Hawkins C Rutka JT Chuang NA Chuang SH Snead OC 《Journal of child neurology》2005,20(4):377-384
The purpose of this study was to identify the pathologic features that predict postoperative outcome in children with cortical dysplasia adjacent to dysembryoplastic neuroepithelial tumors. We reviewed the records of children with dysembryoplastic neuroepithelial tumor who underwent epilepsy surgery and who had at least 1 year of surgical follow-up. We divided the dysembryoplastic neuroepithelial tumors into three pathology classes (simple, complex, and nonspecific), categorized adjunctive cortical dysplasia into four types, and compared histopathology with seizure outcomes. We identified 26 children with dysembryoplastic neuroepithelial tumors. Dysembryoplastic neuroepithelial tumors were complex in 19 patients (73%), simple in 6 (23%), and nonspecific in 1 (4%). Cortical dysplasia was adjacent to dysembryoplastic neuroepithelial tumors in 18 patients. Six patients had type IA cortical dysplasia, 5 had type IB, 3 had type IIA, and 1 had type IIB. The 3 remaining patients had repeated surgeries; of these, 2 patients had cortical dysplasias of type IA/IB and 1 was type IIA/IIB. Eight (39%) of 18 patients with dysembryoplastic neuroepithelial tumors and cortical dysplasia required further surgery for recurrent intractable seizures (P < .05), whereas none of 8 patients without cortical dysplasia required additional surgery. Of 13 patients with type I cortical dysplasia, only 4 had a poor seizure outcome, whereas all 5 patients with type II had a poor seizure outcome postoperatively (P < .05). Children with dysembryoplastic neuroepithelial tumor and cortical dysplasia often had recurrent intractable seizures postoperatively and required further epilepsy surgery. Cortical dysplasia adjacent to dysembryoplastic neuroepithelial tumor can play a role in the epileptogenicity of dysembryoplastic neuroepithelial tumor. Complete resection of a dysembryoplastic neuroepithelial tumor and its adjacent cortical dysplasia should be considered. 相似文献
993.
Ochi A Otsubo H Iida K Oishi M Elliott I Weiss SK Kutomi T Nakayama T Sharma R Chuang SH Rutka JT Snead OC 《Journal of child neurology》2005,20(11):885-892
We used electroencephalographic (EEG) and magnetoencephalographic dipole lateralizations to identify the primary epileptogenic hemisphere in 41 children with intractable localization-related epilepsy. We compared EEG and magnetoencephalographic dipole lateralizations, EEG ictal onsets, and magnetic resonance images (MRIs). Concordant lateralization of EEG and magnetoencephalographic dipoles (> 50% of each lateralizing to the same hemisphere) occurred in 34 patients, with EEG ictal onsets in the same hemisphere in 23 (68%) and concordant MRI lesions in 23 (68%). Focal resection in 16 of 20 patients resulted in a good surgical outcome. Of the seven children with nonconcordant magnetoencephalographic and EEG lateralizations, one (14%) had EEG ictal onset and one (14%) had MRI lesions that lateralized; none had surgery. The relationship between lateralized EEG and magnetoencephalographic dipoles forecasts surgical candidacy. Concordant lateralizations predict good seizure control after surgery by identifying the primary epileptogenic hemisphere. Discordant lateralizations signify an undetermined epileptogenic hemisphere and contraindicate surgery without further testing. 相似文献
994.
Roberts LW Warner TD Geppert CM Rogers M Green Hammond KA 《Comprehensive psychiatry》2005,46(1):27-33
PURPOSE: Insights from genetic research may greatly improve our understanding of physical and mental illnesses and assist in the prevention of disease. Early experience with genetic information suggests that it may lead to stigma, discrimination, and other psychosocial harms, however, and this may be particularly salient in some settings, such as the workplace. Despite the importance of these issues, little is known about how healthy adults, including workers, perceive and understand ethically important issues in genetic research pertaining to physical and mental illness. METHOD: We developed, pilot tested, and administered a written survey and structured interview to 63 healthy working adults in 2 settings. For this paper, we analyzed a subset of items that assessed attitudes toward ethically relevant issues related to participation in genetic research on physical and mental illness, such as its perceived importance, its acceptability for various populations, and appropriate motivations for participation. RESULTS: Our respondents strongly endorsed the importance of physical and mental illness genetic research. They viewed participation as somewhat to very acceptable for all 12 special population groups we asked about, including persons with mental illness. They perceived more positives than negatives in genetic research participation, giving neutral responses regarding potential risks. They affirmed many motivations for participation to varying degrees. Men tended to affirm genetic research participation importance, acceptability, and motivations more strongly than women. CONCLUSION: Healthy working persons may be willing partners in genetic research related to physical and mental illnesses in coming years. This project suggests the feasibility and value of evidence-based ethics inquiry, although further study is necessary. Evidence regarding stakeholders' perspectives on ethically important issues in science may help in the development of research practices and policy. 相似文献
995.
Previous studies have demonstrated disruptions of motor activities and a decrease of extracellular dopamine level in the striatum of rats exposed to high pressure of nitrogen. Men exposed to nitrogen pressure develop also motor and cognitive disturbances related to inert gas narcosis. After repetitive exposures, adaptation to narcosis was subjectively reported. To study the effects of repetitive exposures to hyperbaric nitrogen-oxygen, male Sprague-Dawley rats were implanted in the striatum with multifiber carbon dopamine-sensitive electrodes. After recovery from surgery, free-moving rats were exposed for 2 h up to 3 MPa of nitrogen-oxygen mixture before and after one daily exposure to 1 MPa of nitrogen-oxygen, for 5 consecutive days. Dopamine release was measured by differential pulse voltammetry and motor activities were quantified using piezo-electric captor. At the first exposure to 3 MPa, the striatal dopamine level decreased during the compression (-15%) to reach -20% during the stay at 3 MPa. Motor activities were increased during compression (+15%) and the first 60 min at constant pressure (+10%). In contrast, at the second exposure to 3 MPa, an increase of dopamine of +15% was obtained during the whole exposure. However, total motor activities remained unchanged as compared to the first exposure. Our results confirm that nitrogen exposure at 3 MPa led to a decreased striatal dopamine release and increased motor disturbances in na?ve rats. Repetitive exposures to 1 MPa of nitrogen induced a reversal effect on the dopamine release which suggests a neurochemical change at the level of the neurotransmitter regulation processes of the basal ganglia. In contrast, motor activity remained quantitatively unchanged, thus suggesting that dopamine is not involved alone in modulating these motor disturbances. 相似文献
996.
Common and differential neural mechanisms supporting imitation of meaningful and meaningless actions
Rumiati RI Weiss PH Tessari A Assmus A Zilles K Herzog H Fink GR 《Journal of cognitive neuroscience》2005,17(9):1420-1431
Neuropsychological studies indicate that, after brain damage, the ability to imitate meaningful or meaningless actions can be selectively impaired. However, the neural bases supporting the imitation of these two types of action are still poorly understood. Using PET, we investigated in 10 healthy individuals the neural mechanisms of imitating novel, meaningless actions and familiar, meaningful actions. Data were analyzed using SPM99. During imitation, a significant positive correlation (p < .05, corrected) of regional cerebral blood flow with the amount of meaningful actions was observed in the left inferior temporal gyrus only. In contrast, a significant positive correlation (p < .05, corrected) with the amount of meaningless movements was observed in the right parieto-occipital junction. The direct categorical comparison of imitating meaningful (100%) relative to meaningless (100%) actions showed differential increases in neural activity (p < .001, uncorrected) in the left inferior temporal gyrus, the left parahippocampal gyrus, and the left angular gyrus. The reverse categorical comparison of imitating meaningless (100%) relative to meaningful (100%) actions revealed differential increases in neural activity (p < .001, uncorrected) in the superior parietal cortex bilaterally, in the right parieto-occipital junction, in the right occipital-temporal junction (MT, V5), and in the left superior temporal gyrus. Increased neural activity common to imitation of meaningless and meaningful actions compared to action observation was observed in a network of areas known to be involved in imitation of actions including the primary sensorimotor cortex, the supplementary motor area, and the ventral premotor cortex. These results are compatible with the two-route model of action imitation which suggests that there are at least two mechanisms involved in imitation of actions: a direct mechanism transforming a novel action into a motor output, and a semantic mechanism, on the basis of stored memories, that allows reproductions of known actions. Our results indicate that, in addition to shared neural processes, the direct and the semantic mechanisms that underlie action imitation also draw upon differential neural mechanisms. The direct mechanism underlying imitation of meaningless actions differentially involves visuospatial transformation processes as evidenced by activation of areas belonging to the dorsal stream. In contrast, imitation of meaningful actions differentially involves semantic processing as evidenced by activation of areas belonging to the ventral stream. 相似文献
997.
Henningsen P Jakobsen T Schiltenwolf M Weiss MG 《The Journal of nervous and mental disease》2005,193(2):85-92
The assessment of somatoform disorders is complicated by persistent theoretical and practical questions of classification and assessment. Critical rethinking of professional concepts of somatization suggests the value of complementary assessment of patients' illness explanatory models of somatoform and other common mental disorders. We undertook this prospective study to assess medically unexplained somatic symptoms and their patient-perceived causes of illness and to show how patients' explanatory models relate to professional diagnoses of common mental disorders and how they may predict the short-term course of illness. Tertiary care patients (N=186) with prominent somatoform symptoms were evaluated with the Structured Clinical Interview for DSM-IV, a locally adapted Explanatory Model Interview to elicit patients' illness experience (priority symptoms) and perceived causes, and clinical self-report questionnaires. The self-report questionnaires were administered at baseline and after 6 months. Diagnostic overlap between somatoform, depressive, and anxiety disorders occurred frequently (79.6%). Patients explained pure somatoform disorders mainly with organic causal attributions; they explained pure depressive and/or anxiety disorders mainly with psychosocial perceived causes, and patients in the diagnostic overlap group typically reported mixed causal attributions. In this last group, among patients with similar levels of symptom severity, organic perceived causes were related to a lower physical health sum score on the MOS Short Form, and psychosocial perceived causes were related to less severe depressive symptoms, assessed with the Hospital Anxiety and Depression Scale at 6 months. Among patients meeting criteria for comorbid somatoform with anxiety and/or depressive disorders, complementary assessment of patient-perceived causes, a key element of illness explanatory models, was related to levels of functional impairment and short-term prognosis. For such patients, causal attributions may be particularly useful to clarify clinically significant features of common mental disorders and thereby contribute to clinical assessment. 相似文献
998.
Japans Silver Human Resource Center (SHRC) program provides part-time, paid employment to retirement-aged men and women. We studied 393 new program participants and examined whether part-time work influenced their well-being or ikigai. The participants were divided into those who had worked in SHRC-provided jobs in the preceding year, and those who had not. Gender-stratified regression models were fitted to determine whether SHRC employment was associated with increased well-being. For men, actively working at a SHRC job was associated with greater well-being, compared to inactive members. And men with SHRC jobs and previous volunteering experience had the greatest increase in well-being. Women SHRC job holders did not experience increased well-being at the years end. The study concludes that there is justification for exploring the usefulness of a similar program for American retirees who desire post-retirement part-time work. 相似文献
999.
1000.