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   9280篇
  免费   879篇
  国内免费   49篇
耳鼻咽喉   115篇
儿科学   251篇
妇产科学   295篇
基础医学   1281篇
口腔科学   186篇
临床医学   1239篇
内科学   1784篇
皮肤病学   88篇
神经病学   960篇
特种医学   302篇
外国民族医学   1篇
外科学   1262篇
综合类   209篇
一般理论   9篇
预防医学   789篇
眼科学   291篇
药学   479篇
中国医学   41篇
肿瘤学   626篇
  2023年   67篇
  2022年   85篇
  2021年   264篇
  2020年   180篇
  2019年   281篇
  2018年   287篇
  2017年   229篇
  2016年   212篇
  2015年   243篇
  2014年   343篇
  2013年   433篇
  2012年   575篇
  2011年   637篇
  2010年   338篇
  2009年   295篇
  2008年   565篇
  2007年   522篇
  2006年   469篇
  2005年   489篇
  2004年   435篇
  2003年   402篇
  2002年   386篇
  2001年   223篇
  2000年   198篇
  1999年   174篇
  1998年   127篇
  1997年   76篇
  1996年   80篇
  1995年   76篇
  1994年   65篇
  1993年   51篇
  1992年   148篇
  1991年   105篇
  1990年   109篇
  1989年   96篇
  1988年   124篇
  1987年   87篇
  1986年   84篇
  1985年   82篇
  1984年   70篇
  1983年   40篇
  1982年   31篇
  1981年   28篇
  1980年   26篇
  1979年   43篇
  1978年   26篇
  1977年   30篇
  1973年   24篇
  1969年   26篇
  1967年   23篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
European Journal of Orthopaedic Surgery & Traumatology - The goals of this study were to compare patient satisfaction and wound-related complications in patients receiving 2-octyl cyanoacrylate...  相似文献   
2.
In the USA, the Black Church is among the most important institutions in the Black community, offering numerous spiritual, social and health benefits. Yet, the presence of homonegativity in many Black Churches may mitigate those effects for gay Black youth. This research examines the role of the Church in the lives of gay and bisexual Black youth to understand how they reconcile any tension between their religious and sexual identities. Through interviews with pastors of Black churches (n = 21) and young Black men who have sex with men (n = 30), we explored homonegativity and young men’s experiences within the Black Church. Findings reveal that despite the prevalence of homonegativity within Black churches, religious involvement remains important for young men and many remain involved in non-affirming churches. The importance of the Church for young men stems from their significant involvement as youth and the integration of religion, family and community. Young men may not be able to leave their religious homes as readily as other gay youth given the cultural relevance of the Church. As a result, young men made attempts to conceal their sexuality in church to avoid shame and gossip and find opportunities to balance their sexuality and religiosity.  相似文献   
3.
Graefe's Archive for Clinical and Experimental Ophthalmology - Retinal microvascular endothelial dysfunction is thought to be of importance in the development of ocular vascular diseases....  相似文献   
4.

Background

In the emergency department, rib fractures are a common finding in patients who sustain chest trauma. Rib fractures may be a sign of significant, underlying pathology, especially in the elderly patients where rib fractures are associated with significant morbidity and mortality. To date, no studies have evaluated the ability of ultrasound to detect rib fractures using cadaver models and subsequently use this model as a teaching tool.

Objectives

The purpose of this study was to determine if it is possible to generate rib fractures on cadaver models which could be accurately identified using ultrasound.

Methods

This was a cross-sectional study performed during one session at a cadaver lab. A single hemithorax from four adult cadavers were used as models. Single rib fractures on each of rib five through eight were created. Four subjects, blinded to the normal versus fractured ribs, were asked to identify the presence of a fracture on each rib.

Results

A total of 8 of 16 potential ribs had fractured induced by study staff. Mean accuracy was 55% for all subjects. The overall sensitivity and specificity for detecting rib fractures was 50% (CI: 31.89–68.11) and 59.38% (CI: 35.69–73.55) respectively. The overall PPV and NPV was 55.17% and 54.29% respectively.

Conclusions

In this pilot study, subjects were not able to detect induced rib fractures using ultrasound on cadaver models. The use of this model as a teaching tool in the detection of rib fractures requires further investigation.  相似文献   
5.
6.

Background

Most elderly trauma patients suffer blunt head injury and many utilize antithrombotic (AT) medications. The utility of delayed CT-head (D-CTH) in neurologically intact elderly patients using AT who have an intracranial hemorrhage (ICH) on presentation is unknown. We hypothesized that D-CTH would not alter clinical management and aimed to evaluate the role of D-CTH in this population.

Methods

A retrospective cohort study was performed. Patients ≥65 years sustaining blunt head injuries from January 2010 to July 2017 were identified using our level 1 trauma center database. AT-patients presenting with ICH who underwent D-CTH were included. Patients with worsened ICH were compared to those with stable to improved ICH on D-CTH. AT-patients were compared to a cohort of non-AT patients. Fisher’s Exact and Mann-Whitney U tests were utilized and a power analysis conducted.

Results

137?A?T and 34 non-AT patients were identified. There was no difference in hemorrhage progression or appearance of new ICH. No patient had a change in management from D-CTH in either cohort. AT-patients were slightly older (p?<?0.001), but cohorts were otherwise similar.50 AT-patients with worsened ICH were compared to 87 with stable ICH. There was no difference in cohort demographics. Hemorrhage progression did not vary with type of AT used but did increase if multiple types of synchronous ICH were present (p?<?0.001).

Conclusions

Our data supports abstaining from routine D-CTH of elderly ICH patients with an intact neurologic examination who are utilizing aspirin, clopidogrel or warfarin. Conclusions cannot be drawn regarding new oral anticoagulants (NOACs) given low enrollment. Further multicenter study is required to provide adequate power and detect small levels of management change.  相似文献   
7.
8.
The reliable change index (RCI) expresses change relative to its associated error, and is useful in the identification of post-operative cognitive dysfunction (POCD). This paper examines four common RCIs that each account for error in different ways. Three rules incorporate a constant correction for practice effects and are contrasted with the standard RCI that had no correction for practice. These rules are applied to 160 patients undergoing coronary artery bypass graft (CABG) surgery who completed neuropsychological assessments preoperatively and 1 week post-operatively using error and reliability data from a comparable healthy non-surgical control group. The rules all identify POCD in a similar proportion of patients, but the use of the within subject standard deviation, expressing the effects of random error, as an error estimate is a theoretically appropriate denominator when a constant error correction, removing the effects of systematic error, is deducted from the numerator in a RCI.  相似文献   
9.
Genotoxins, such as polycyclic aromatic compounds, are ubiquitous in urban and industrial environments. Our understanding of the role that these chemicals play in generating DNA sequence mutations is predominantly derived from laboratory studies with specific genotoxins or extracts of contaminants from environmental media. Most assays are not indicative of the germinal effects of exposure in situ to complex mixtures of common environmental mutagens. Using multilocus DNA fingerprinting, we found the mutation rate in herring gulls inhabiting a heavily industrialized urban harbor (Hamilton Harbour, Ontario) to be more than twice as high as three rural sites: Kent Island, Bay of Fundy; Chantry Island, Lake Huron; and Presqu'ile Provincial Park in Lake Ontario. Overall we found a mutation rate of 0.017 +/- 0.004 per offspring band in Hamilton, 0.006 +/- 0.002 at Kent Island, 0.002 +/- 0.002 from Chantry Island, and 0.004 +/- 0.002 from Presqu'ile Provincial Park. The mutation rate from the rural sites (pooled) was significantly lower than the rate observed in Hamilton Harbour (Fisher's exact test, two-tailed; P = 0.0006). These minisatellite DNA mutations may be important biomarkers for heritable genetic changes resulting from in situ exposure to environmental genotoxins in a free-living vertebrate species.  相似文献   
10.
The origin and nature of osteoclast-like multinucleated giant cells (OMGCs), in extraskeletal neoplasms, is uncertain. The ultrastructure, antigenic phenotype and function of OMGCsm in a breast carcinoma were studied in order to clarify the relationship between OMGCs, osteoclasts and other cells of the mononuclear phagocyte system (MPS). OMGCs resorbed cortical bone in a manner similar to osteoclasts. However, unlike osteoclasts, OMGCs did not possess a ruffled border or clear zone, and expressed HLA-DR and Fc receptors and CD14, CD16, CD18 and CD11 (p150,95) antigens. In addition, OMGCs failed to respond morphologically to calcitonin and were directly stimulated by parathyroid hormone (PTH) to increase bone resorption. These findings suggest that OMGCs are a specific type of macrophage polykaryon distinct from both osteoclasts and other types of inflammatory polykaryon. Occasional smaller (20-25 microns) macrophage-like cells were also associated with resorption pits. Bone resorption by OMGCs isolated from the breast indicates that a cell of the MPS can be transplanted to a new tissue location and perform a highly specialised function appropriate to an MPS cell of that tissue (i.e. the osteoclast). PTH stimulation of bone resorption by OMGCs suggests that PTH or a PTH-like protein, may be involved in the bone resorption and consequent hypercalcaemia associated with metastatic breast cancer.  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