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   993篇
  免费   111篇
  国内免费   10篇
耳鼻咽喉   1篇
儿科学   53篇
妇产科学   12篇
基础医学   96篇
口腔科学   36篇
临床医学   152篇
内科学   231篇
皮肤病学   53篇
神经病学   81篇
特种医学   114篇
外科学   123篇
综合类   14篇
预防医学   39篇
眼科学   11篇
药学   50篇
肿瘤学   48篇
  2023年   10篇
  2022年   4篇
  2021年   12篇
  2020年   15篇
  2019年   28篇
  2018年   39篇
  2017年   25篇
  2016年   27篇
  2015年   32篇
  2014年   44篇
  2013年   45篇
  2012年   40篇
  2011年   40篇
  2010年   39篇
  2009年   68篇
  2008年   32篇
  2007年   25篇
  2006年   37篇
  2005年   32篇
  2004年   34篇
  2003年   29篇
  2002年   20篇
  2001年   11篇
  2000年   13篇
  1999年   19篇
  1998年   34篇
  1997年   34篇
  1996年   39篇
  1995年   27篇
  1994年   26篇
  1993年   32篇
  1992年   14篇
  1991年   14篇
  1990年   15篇
  1989年   17篇
  1988年   14篇
  1987年   24篇
  1986年   16篇
  1985年   14篇
  1984年   8篇
  1983年   6篇
  1982年   5篇
  1981年   11篇
  1980年   6篇
  1978年   4篇
  1976年   6篇
  1974年   3篇
  1973年   4篇
  1972年   4篇
  1970年   3篇
排序方式: 共有1114条查询结果,搜索用时 15 毫秒
61.
Background and objectives: There are no large volume comparative studies available to compare the efficacy of lasers over lights for hair removal in Fitzpatrick V and VI skin types. This study is designed to compare the efficacy of Nd:YAG laser versus IPL in the darker skin types. Study design/materials and methods: Thirty-nine patients included in Group-1 were treated with Nd:YAG and 31 in Group-2 with IPL. Both groups received 5 sessions of treatment. The hair counts were assessed using digital photography and manual counting method before and after treatment and the results were analysed. Patient satisfaction scores and pain scores were recorded in each session and compared. Results: Mean hair reduction in the IPL group was 25.70 and Nd:YAG group was 24.12 (95% CI). In the Nd:YAG group, 59% of subjects had burning sensation while the figure was 32.3% in IPL group. Burning was less in IPL group (p < 0.023). There were no statistically significant differences noticed regarding hyperpigmentation in both the groups (p < 0.115). Conclusion: Both Nd:YAG and IPL are equally effective for epilation of the darker skin types. Nd:YAG is associated with mild burning sensation in a significant number of patients. Patient satisfaction scores were comparable in both the groups.  相似文献   
62.
Background: The relationship between microbiology and histology in patients with ventilator-associated pneumonia has been sparsely described.

Methods: Twenty-five patients who died in the intensive care unit after their lungs had been mechanically ventilated for 72 h were studied. Twenty of the 25 died with clinical suspicion of pulmonary infection. A total of 375 immediate postmortem pulmonary biopsies were obtained after death and processed for quantitative microbiology and histology. Four evolutionary stages of pneumonia were defined: early, intermediate, advanced, and resolution.

Results: At least one specimen with histologic evidence of pneumonia was found in all but two patients (92%). Histologic pneumonia was a widespread and frequent process (46% of biopsies examined) involving predominantly the lower lobes (55% of all biopsies with pneumonia) and showing different histopathologic stages of progression coexisting in the same lung lobes. Lung cultures were frequently polymicrobial (149 of 375, 40% of the pulmonary biopsy cultures, and 20 of 25, 80% of the cases) and not always yielding the same pathogen (19 microorganisms) when comparing one lung to the other. Histopathology and microbiologic biopsy cultures showed a weak relationship (28% and 49% of species had counts greater or equal to 103 cfu/g in samples without pneumonia from patients with and without prior antibiotic treatment, respectively). Histopathologic evolutionary stages were not associated with any differences in quantitative culture results of pulmonary biopsies, independently of prior administration of antibiotics. Higher bacterial concentrations of biopsy cultures were associated with the absence of prior antibiotic treatment.  相似文献   

63.
Objectives: Avoiding placement of unnecessary urinary catheters (UCs) in the emergency department (ED) affects UC utilization during hospitalization. The authors sought to evaluate the effect of establishing institutional guidelines for appropriate UC placement coupled with emergency physician (EP) education on UC utilization. Methods: Urinary catheter utilization was measured before and after the establishment of guidelines and EP education. Data collected included the presence of a UC on ED arrival, placement of a UC in the ED, documentation of a physician order for UC placement, reasons for placement, and compliance with the guidelines. Chi‐square analyses were used to study the association between pre‐ and postintervention time periods and catheter use. Results: A total of 377 (15%) patients had UCs; only 151 (47%) UCs initially placed in the ED had a physician order documented. UC placement was appropriately indicated in 75.5% of patients with a documented physician order, but in only 52% of cases without a documented physician order (p < 0.001). The physician intervention was associated with an overall reduction in UC utilization from 16.4% to 13% (p = 0.018). Physicians ordered 40% fewer UCs postintervention compared to preintervention. Preintervention, a physician order for UC placement was found indicated in 72.6% patients, compared to 82.2% patients with UC placed postintervention (p = 0.21). Conclusions: Establishing guidelines for UC placement and physician education in the ED were associated with a marked reduction in utilization. However, addressing appropriate UC utilization may require evaluating other factors such as nursing influence on utilization. ACADEMIC EMERGENCY MEDICINE 2010; 17:337–340 © 2010 by the Society for Academic Emergency Medicine  相似文献   
64.
A case of double aortic arch that was well visualized using transthoracic echocardiography is reported. A 38‐year‐old man underwent transthoracic echocardiography for the evaluation of dyspnea. A suprasternal view of transthoracic echocardiography showed the ascending aorta bifurcate to left and right aortic arches, with blood flow from the ascending aorta to bilateral aortic arches. The diagnosis of right side–dominant double aortic arch was made, and the patient's symptom was conceivably related to compression of the trachea due to a vascular ring. This report indicates the potential usefulness of transthoracic echocardiography for noninvasive detection of double aortic arch in adults.  相似文献   
65.
ObjectivesTo evaluate the effect of phlebectomy on venous reflux and diameter of the great saphenous vein (GSV).DesignProspective cohort study.MethodPatients presenting with reflux in the GSV resulting in varicose veins were included in this series. Patients were treated by phlebectomy for dilated and incompetent tributaries of the GSV with conservation of the incompetent GSV. We measured reflux duration (RD), peak reflux velocity (PRV) and the diameter of the GSV using duplex ultrasound imaging at inclusion and 1 month after surgery.PatientsWe included 55 limbs in 54 patients (30 women and 24 men) aged from 37 to 83 (mean age 63) years.ResultsFollowing treatment we observed a significant reduction of the mean RD (0.81s vs. 1.5 s p < 0.01, t-test), mean PRV (120 mm s?1 vs. 249 mm s?1 p < 0.01, t-test) and mean diameter of the GSV (SFJ = 5.6 mm vs. 6.7 mm, p < 0.01, sub-terminal valve 4.8 mm vs. 4.4 mm p < 0.05, mid-thigh 5.0 mm vs. 4.2 mm, p < 0.01, knee 4.0 mm vs. 5.3 mm p < 0.01, mid-calf 2.7 mm vs. 4.0 mm, p < 0.01, t-test).ConclusionsWe noted reduced reflux in the GSV after phlebectomy with a significant reduction in RD and PRV. Phlebectomy also led to a significant reduction in GSV diameter. These data suggest that the haemodynamics and the diameter of the SV can be improved by using a treatment focussing on the saphenous tributaries.  相似文献   
66.
67.

Background  

High accrual to clinical trials enables new treatment strategies to be tested rapidly, accurately and with generalisability. Ethical standards also must be high so that participation is voluntary and informed. However, this can be difficult to achieve in trials with complex designs and in those which are closely embedded in clinical practice. Optimal recruitment requires a balance of both ethical and accrual considerations. In the context of a trial of stratified treatments for children with acute lymphoblastic leukaemia (UKALL2003) we examined how recruitment looked to an observer and how it felt to the parents, to identify how doctors' communication could promote or inhibit optimal recruitment.  相似文献   
68.
69.
70.
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