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   45553篇
  免费   4658篇
  国内免费   180篇
耳鼻咽喉   2256篇
儿科学   258篇
妇产科学   81篇
基础医学   2340篇
口腔科学   3141篇
临床医学   3930篇
内科学   1404篇
皮肤病学   114篇
神经病学   603篇
特种医学   2749篇
外国民族医学   3篇
外科学   17360篇
综合类   7397篇
预防医学   1437篇
眼科学   215篇
药学   2444篇
  65篇
中国医学   1602篇
肿瘤学   2992篇
  2024年   16篇
  2023年   789篇
  2022年   1172篇
  2021年   1747篇
  2020年   2203篇
  2019年   1658篇
  2018年   1493篇
  2017年   1710篇
  2016年   1939篇
  2015年   1734篇
  2014年   3525篇
  2013年   3275篇
  2012年   3040篇
  2011年   3325篇
  2010年   2698篇
  2009年   2641篇
  2008年   2362篇
  2007年   2359篇
  2006年   2011篇
  2005年   1891篇
  2004年   1607篇
  2003年   1238篇
  2002年   997篇
  2001年   841篇
  2000年   664篇
  1999年   596篇
  1998年   446篇
  1997年   407篇
  1996年   267篇
  1995年   248篇
  1994年   204篇
  1993年   191篇
  1992年   153篇
  1991年   115篇
  1990年   68篇
  1989年   70篇
  1988年   57篇
  1987年   61篇
  1986年   58篇
  1985年   64篇
  1984年   59篇
  1983年   67篇
  1982年   72篇
  1981年   56篇
  1980年   46篇
  1979年   41篇
  1978年   32篇
  1977年   25篇
  1976年   22篇
  1975年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Aim: To measure functional recovery and determine risk factors for failure to return to the prefracture level of mobility of hip fracture patients 1 year postoperatively. Methods: A prospective cohort follow‐up study of 390 hip fracture patients aged 65 years and older was carried out. Patients were stratified in categories based on prefracture mobility: mobile without aid, with aid in‐ and outdoors, or only mobile indoors. Immobile patients were excluded. Risk factors for not regaining prefracture mobility were identified. Results: Nearly half of all patients regained their prefracture level of mobility after 1 year. Mobile patients without an aid were less likely to return to their prefracture mobility level compared with patients who were mobile with aid or mobile indoors. After 1 year, 18.7% of all patients had become immobile. Most important independent risk factors for failure to return to the prefracture level of mobility were a limited prefracture level of activities of daily living and a delirium during admission. Conclusions: The risk not to regain prefracture mobility is highest in mobile patients without an aid. The risk of becoming immobile is higher in those having a lower prefracture mobility. Activities of daily living dependence and delirium were the main risk factors for not regaining mobility. Geriatr Gerontol Int 2013; 13: 334–341 .  相似文献   
3.
4.
PurposeTo prospectively evaluate the incidence of pulmonary cement embolism (PCE) after vertebroplasty in procedures performed under real-time computed tomographic (CT) fluoroscopy guidance.Materials and MethodsA total of 85 vertebroplasties were performed in 51 consecutive patients (31 women, 20 men; mean age, 71.9 y; range, 48–92 y) in 51 sessions. The needle was inserted with guidance from intermittent single-shot CT scans, and intermittent CT fluoroscopy was used during cement injection only. To reduce the risk of extravertebral or extraosseous leakage, several procedures (cement injection stopping/slowing, needle position changes) were employed. The chest and treated bone were scanned immediately after vertebroplasty. These CT images included the entire thorax as well as the treated vertebrae.ResultsNo cement emboli were observed on CT after vertebroplasty. After 85 vertebroplasty procedures, 44 extravertebral leaks were detected. Epidural leaks were observed on CT in six treated vertebrae (7%), in 12 cases in the anterior external venous plexus (14.1%), in five in the azygos vein (5.8%), in 19 in the disc space (22%), and in two in the foraminal space (2.3%). On a per-patient basis, the odds of leaks increased with the number of vertebroplasties (P = .05) and the volume of cement used (P = .0412). There was also a higher probability of leak (P < .05) for osteoporotic vertebral compression fractures (67.9%; 95% confidence interval, 47.7%–84.1%) than osteolytic spinal metastases (34.8%; 16.4%–57.3%).ConclusionsPCE did not occur after vertebroplasty under CT fluoroscopy guidance. Further larger prospective vertebroplasty studies are needed to compare the rates of PCE for CT versus conventional fluoroscopic guidance.  相似文献   
5.
We investigated the effect of eye‐in‐head and head‐on‐trunk direction on heading discrimination. Participants were passively translated in darkness along linear trajectories in the horizontal plane deviating 2° or 5° to the right or left of straight‐ahead as defined by the subject's trunk. Participants had to report whether the experienced translation was to the right or left of the trunk straight‐ahead. In a first set of experiments, the head was centered on the trunk and fixation lights directed the eyes 16° either left or right. Although eye position was not correlated with the direction of translation, rightward reports were more frequent when looking right than when looking left, a shift of the point of subjective equivalence in the direction opposite to eye direction (two of the 38 participants showed the opposite effect). In a second experiment, subjects had to judge the same trunk‐referenced trajectories with head‐on‐trunk deviated 16° left. Comparison with the performance in the head‐centered paradigms showed an effect of the head in the same direction as the effect of eye eccentricity. These results can be qualitatively described by biases reflecting statistical regularities present in human behaviors such as the alignment of gaze and path. Given the known effects of gaze on auditory localization and perception of straight‐ahead, we also expect contributions from a general influence of gaze on the head‐to‐trunk reference frame transformations needed to bring motion‐related information from the head‐centered otoliths into a trunk‐referenced representation.  相似文献   
6.
Horizontal root fractures (HRF) usually affect anterior teeth of male patients as a result of trauma. The consequences can be complex because of combined damage to different tissues, but it has been reported that root fractures undergo healing in majority cases. Diagnosis of HRF must be based on clinical findings, sensibility tests, and radiographic examination. The cone‐beam computed tomography (CBCT) has already been proven to be superior among other radiographic modalities for diagnostic imaging of root fractures. However, CBCT in these cases needs to be used in a careful manner, and only when the radiation exposure should be justified by the potential diagnostic benefits and improvement of the treatment results. This case report describes a case of spontaneously healed horizontal root fracture with displacement of the fragments and discusses the usefulness of CBCT in the follow‐up of root fractures cases.  相似文献   
7.
8.
A 4 year‐old girl was referred for CT of her neck for suspected submental lymphadenopathy and was found to have an incidental low‐attenuation thyroid mass. Subsequent thyroid ultrasound showed a heterogeneous thyroid mass with punctate areas of increased echogenicity. Cytologic examination was consistent with ectopic intrathyroidal thymic nodule. We review the presentation of ectopic thymic tissue, especially in the thyroid gland. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 41:319–320, 2013  相似文献   
9.
10.
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