首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   9048篇
  免费   649篇
  国内免费   25篇
耳鼻咽喉   89篇
儿科学   221篇
妇产科学   195篇
基础医学   1287篇
口腔科学   137篇
临床医学   1160篇
内科学   1658篇
皮肤病学   167篇
神经病学   971篇
特种医学   239篇
外科学   1503篇
综合类   103篇
一般理论   4篇
预防医学   857篇
眼科学   197篇
药学   494篇
中国医学   8篇
肿瘤学   432篇
  2024年   7篇
  2023年   104篇
  2022年   166篇
  2021年   336篇
  2020年   192篇
  2019年   359篇
  2018年   403篇
  2017年   273篇
  2016年   273篇
  2015年   258篇
  2014年   429篇
  2013年   512篇
  2012年   780篇
  2011年   770篇
  2010年   386篇
  2009年   324篇
  2008年   565篇
  2007年   585篇
  2006年   546篇
  2005年   523篇
  2004年   423篇
  2003年   335篇
  2002年   365篇
  2001年   62篇
  2000年   48篇
  1999年   58篇
  1998年   62篇
  1997年   44篇
  1996年   48篇
  1995年   43篇
  1994年   38篇
  1993年   37篇
  1992年   42篇
  1991年   24篇
  1990年   22篇
  1989年   29篇
  1988年   33篇
  1987年   19篇
  1986年   23篇
  1985年   20篇
  1984年   12篇
  1983年   20篇
  1982年   11篇
  1981年   16篇
  1980年   11篇
  1979年   8篇
  1977年   7篇
  1975年   7篇
  1971年   6篇
  1969年   6篇
排序方式: 共有9722条查询结果,搜索用时 13 毫秒
1.
2.

Background

Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.

Methods

We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).

Results

Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.

Conclusions

Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation.  相似文献   
3.
Temporoparietal and posterior cingulate metabolism deficits characterize patients with Alzheimer's disease (AD). A H(2)(15)O resting PET scan covariance pattern, derived by using multivariate techniques, was previously shown to discriminate 17 mild AD patients from 16 healthy controls. This AD covariance pattern revealed hypoperfusion in bilateral inferior parietal lobule and cingulate; and left middle frontal, inferior frontal, precentral, and supramarginal gyri. The AD pattern also revealed hyperperfusion in bilateral insula, lingual gyri, and cuneus; left fusiform and superior occipital gyri; and right parahippocampal gyrus and pulvinar. In an independent sample of 23 outpatients with mild cognitive impairment (MCI) followed at 6-month intervals, the AD pattern score was evaluated as a predictor of cognitive decline. In this MCI sample, an H2(15)O resting PET scan was carried out at baseline. Mean duration of follow-up was 48.8 (SD 15.5) months, during which time six of 23 MCI patients converted to AD. In generalized estimating equations (GEE) analyses, controlling for age, sex, education, and baseline neuropsychological scores, increased AD pattern score was associated with greater decline in each neuropsychological test score over time (Mini Mental State Exam, Selective Reminding Test delayed recall, Animal Naming, WAIS-R digit symbol; Ps<0.01-0.001). In summary, a resting PET covariance pattern previously reported to discriminate AD patients from control subjects was applied prospectively to an independent sample of MCI patients and found to predict cognitive decline. Independent replication in larger samples is needed before clinical application can be considered.  相似文献   
4.
5.
This paper concerns the diagnostic classification of nonaffective acute remitting psychosis (NARP), which we also term acute brief psychosis. We argue that NARP can be delineated from both schizophrenia and the affective psychoses and considered as a single diagnosis. As indicated by the term NARP, four criteria would be central to the diagnosis: 1. nonaffective, 2. acute onset (over less than two weeks), 3. recovery within a brief duration (less than six months), and 4. psychosis broadly defined. We review the rationale and the empirical evidence for this proposed classification.  相似文献   
6.
Long-term outcome of completion gastrectomy for nonmalignant disease   总被引:1,自引:1,他引:0  
Between 1989 and 1995 we performed completion gastrectomy for non-malignant disease in 21 patients (11 men and 10 women, mean age 48.4 years). These patients had undergone a total of 48 prior gastric operations. Indications for completion gastrectomy in this group were anastomotic ulceration with stricture in eight patients, alkaline reflux gastritis and/or esophagitis in eight, postsurgical gastroparesis in two, gastroesophageal necrosis in two, and gastrocutaneous fistula in one. Major preoperative symptoms included nausea and vomiting in 16 cases, abdominal pain in 15, dysphagia in 14, heartburn in seven, and weight loss in five. Following completion gastrectomy, five patients (24%) had serious complications and there was one postoperative death (5%). Five patients were lost to follow-up. For the remaining 15 patients, mean follow-up has been 30 months with a range of 1 to 70 months. These patients were all interviewed and eight (53%) report significant improvement, two (13%) report moderate improvement, and four (27%) report no improvement; one patient (7%) has had worsening of symptoms since undergoing completion gastrectomy. The average body weight index was essentially unchanged after completion gastrectomy. We conclude that completion gastrectomy with Roux-en-Y esophagojejunostomy results in a favorable outcome in the majority of selected patients with diseases of the foregut who are unresponsive to less radical treatment. Presented at the Thirty-Seventh Annual Meeting of The Society for Surgery of the Alimentary Tract, San Francisco, Calif., May 19–22, 1996.  相似文献   
7.
Dissociative responses to trauma have been hypothesized to be associated with long-term increases in psychopathology. The purpose of this study was to examine dissociative responses to premilitary, combat-related and postmilitary traumatic events and long-term psychopathology in Vietnam combat veterans with (n = 34) and without (n = 28) posttraumatic stress disorder (PTSD). PTSD patients reported higher levels of dissociative states at the time of combat-related traumatic events than non-PTSD patients. Higher levels of dissociative states persisted in PTSD patients in the form of higher levels of dissociative states in response to postmilitary traumatic events. In addition, dissociative responses to combat trauma were associated with higher long-term general dissociative symptomatology as measured by scores on the Dissociative Experience Scale, as well as increases in the number of flashbacks since the time of the war. These findings are consistent with previous formulations that dissociation in the face of trauma is a marker of long-term psychopathology.  相似文献   
8.
9.
BACKGROUND CONTEXT: Posterior lumbar interbody fusion (PLIF) is a popular method of arthrodesis for surgical treatment of instabilities and degenerative conditions of the spine. With the introduction of threaded titanium cage devices, surgeons began performing PLIF procedures using these cages as stand-alone devices. Complications have been reported, however, including pseudarthrosis with persistent pain. Outcomes after revision surgical treatment for these patients with failed PLIF are not known. PURPOSE: To prospectively evaluate clinical outcomes of revision fusion surgery in patients who previously underwent posterior lumbar interbody fusion with stand-alone metallic cages resulting in pseudarthrosis. STUDY DESIGN/SETTING: Prospective case series. METHODS: Nineteen patients referred to the senior author were evaluated and diagnosed with pseudoarthrosis having previously undergone a PLIF procedure with stand-alone metallic cages. History, physical exam, and imaging studies were performed preoperatively and postoperatively. All underwent revision posterolateral fusion with iliac crest graft and pedicle screw instrumentation. Patient demographics, SF-36, and Oswestry Disability Index (ODI) data were collected prior to surgery and two years postoperatively. RESULTS: Patients undergoing revision fusion surgery were found to have had extensive facetectomies and pseudarthrosis intraoperatively. Outcomes data was collected on eighteen of nineteen patients (95%). Mean clinical follow up was 3.2 years (range 2.5-3.5 years). Seventeen patients (94%) achieved a solid fusion. Improvement was noted in seven of eight SF-36 sub-categories, but was significant only in two (Physical Function and Role Emotional). There was no significant difference in ODI scores. CONCLUSIONS: Pseudarthrosis should be considered in the differential diagnosis if severe symptoms persist in patients who undergo PLIF with stand-alone metallic cages. Successful revision fusion did not always correlate with improved clinical outcomes in these challenging patients undergoing further surgery. Performing PLIF using stand-alone metallic cages, especially after total resection of the facet joints, is not advocated unless supplemental instrumentation is utilized.  相似文献   
10.
The purpose of this study was to evaluate the dose to normal tissues as a function of increasing margins around the lumpectomy cavity in accelerated partial breast irradiation (APBI) using 3D-conformal radiotherapy (3DCRT). Eight patients with Stage 0-I breast cancer underwent treatment planning for 3DCRT APBI. The clinical target volume (CTV) was defined as a 15-mm expansion around the cavity limited by the chest wall and skin. Three planning target volumes (PTV1, PTV2, PTV3) were generated for each patient using a 0, 5-, and 10-mm expansion around the CTV, for a total margin of 15, 20, and 25 mm. Three treatment plans were generated for every patient using the 3 PTVs, and dose-volume analysis was performed for each plan. For each 5-mm increase in margin, the mean PTV:total breast volume ratio increased 10% and the relative increase in the mean ipsilateral breast dose was 15%. The mean volume of ipsilateral breast tissue receiving 75%, 50%, and 25% of the prescribed dose increased 6% to 7% for every 5 mm increase in PTV margin. Compared to lesions located in the upper outer quadrant, plans for medially located tumors revealed higher mean ipsilateral breast doses and 20% to 22% more ipsilateral breast tissue encompassed by the 25% IDL. The use of 3DCRT for APBI delivers higher doses to normal breast tissue as the PTV increases around the lumpectomy cavity. Efforts should be made to minimize the overall PTV when this technique is used. Ongoing studies will be necessary to determine the clinical relevance of these findings.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号