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   4256篇
  免费   231篇
  国内免费   53篇
耳鼻咽喉   45篇
儿科学   91篇
妇产科学   82篇
基础医学   449篇
口腔科学   116篇
临床医学   310篇
内科学   1012篇
皮肤病学   58篇
神经病学   463篇
特种医学   163篇
外科学   965篇
综合类   5篇
预防医学   111篇
眼科学   107篇
药学   179篇
中国医学   4篇
肿瘤学   380篇
  2024年   5篇
  2023年   37篇
  2022年   108篇
  2021年   197篇
  2020年   107篇
  2019年   121篇
  2018年   151篇
  2017年   101篇
  2016年   137篇
  2015年   156篇
  2014年   193篇
  2013年   257篇
  2012年   334篇
  2011年   347篇
  2010年   196篇
  2009年   187篇
  2008年   225篇
  2007年   232篇
  2006年   221篇
  2005年   180篇
  2004年   191篇
  2003年   168篇
  2002年   171篇
  2001年   78篇
  2000年   43篇
  1999年   45篇
  1998年   29篇
  1997年   23篇
  1996年   15篇
  1995年   18篇
  1994年   11篇
  1993年   16篇
  1992年   19篇
  1991年   21篇
  1990年   29篇
  1989年   11篇
  1988年   13篇
  1987年   12篇
  1986年   11篇
  1985年   19篇
  1984年   12篇
  1983年   10篇
  1982年   10篇
  1981年   9篇
  1979年   6篇
  1978年   5篇
  1971年   5篇
  1969年   9篇
  1968年   6篇
  1966年   7篇
排序方式: 共有4540条查询结果,搜索用时 15 毫秒
61.
Puppa G, Senore C, Sheahan K, Vieth M, Lugli A, Zlobec I, Pecori S, Wang L M, Langner C, Mitomi H, Nakamura T, Watanabe M, Ueno H, Chasle J, Conley S A, Herlin P, Lauwers G Y & Risio M
(2012) Histopathology  61, 562–575 Diagnostic reproducibility of tumour budding in colorectal cancer: a multicentre, multinational study using virtual microscopy Aims: Despite the established prognostic relevance of tumour budding in colorectal cancer, the reproducibility of the methods reported for its assessment has not yet been determined, limiting its use and reporting in routine pathology practice. Methods and results: A morphometric system within telepathology was devised to evaluate the reproducibility of the various methods published for the assessment of tumour budding in colorectal cancer. Five methods were selected to evaluate the diagnostic reproducibility among 10 investigators, using haematoxylin and eosin (H&E) and AE1‐3 cytokeratin‐immunostained, whole‐slide digital scans from 50 pT1–pT4 colorectal cancers. The overall interobserver agreement was fair for all methods, and increased to moderate for pT1 cancers. The intraobserver agreement was also fair for all methods and moderate for pT1 cancers. Agreement was dependent on the participants’ experience with tumour budding reporting and performance time. Cytokeratin immunohistochemistry detected a higher percentage of tumour budding‐positive cases with all methods compared to H&E‐stained slides, but did not influence agreement levels. Conclusions: An overall fair level of diagnostic agreement for tumour budding in colorectal cancer was demonstrated, which was significantly higher in early cancer and among experienced gastrointestinal pathologists. Cytokeratin immunostaining facilitated detection of budding cancer cells, but did not result in improved interobserver agreement.  相似文献   
62.
63.

Purpose

High-dose-rate, multicatheter interstitial brachytherapy is technically complex and operator-dependent, requiring lengthy training and specialized skills. Furthermore, until the advent of contouring on computerized tomography (CT) images, difficulties existed in locating the target volume precisely. The present article reports the results of a study that aimed at producing and validating a 3D-printed template to aid in target volume localization for multicatheter interstitial brachytherapy in patients with breast cancer.

Methods and Materials

Thirteen patients, candidates for accelerated partial breast irradiation or boost, were enrolled in the study. The target volume was defined on CT slices, and a template with empty spaces corresponding to the target volume projection on the patient's skin was produced by a 3D printer. The procedure was compared with the standard method followed in our center (1) visually, by assessing overlap between the target volume projections on the patient's skin, (2) by X-ray findings, and (3) by intraclass correlation coefficient.

Results

Visual assessment and X-ray findings showed the 3D-printed target volume always fell within the standard volume in all 13 patients. The intraclass correlation coefficient indicated moderate agreement for both the medial and the lateral skin projections.

Conclusions

The 3-D printed templates constitute a quick, easy, and reliable method to localize the target volume for high-dose-rate interstitial multicathether brachytherapy in patients with breast cancer and can safely be used in clinical practice.  相似文献   
64.
65.
66.
In fishes, exploitation of aerial gas exchange has evolved independently many times, involving a variety of air-breathing organs. Indeed, air-breathing occurs in at least 49 known families of fish (Graham, 1997). Many amphibious vertebrates, at some stage of their development are actually trimodal breathers that use various combinations of respiratory surfaces to breath both water (skin and/or gill) and air (skin and/or lung). The present review examines the evolutionary implications of air-breathing organs in fishes and the morphology of the peripheral receptors and the neurotransmitter content of the cells involved in the control of air-breathing. Control of breathing, whether gill ventilation or air-breathing, is influenced by feedback from peripheral and/or central nervous system receptors that respond to changes in PO2, PCO2 and/or pH. Although the specific chemoreceptors mediating the respiratory reflexes have not been conclusively identified, studies in water-breathing teleosts have implicated the neuroepithelial cells (NECs) existing in gill tissues as the O2 sensitive chemoreceptors that initiate the cardiorespiratory reflexes in aquatic vertebrates. Some of the air-breathing fishes, such as Protopterus, Polypterus and Amia have been shown to have NECs in the gills and/or lungs, although the role of these receptors and their innervation in the control of breathing is not known. NECs have been also reported in the specialized respiratory epithelia of accessory respiratory organs (ARO’s) of some catfish species and in the gill and skin of the mudskipper Periophthalmodon schlosseri. Unlike teleosts matching an O2-oriented ventilation to ambient O2 levels, lungfishes have central and peripheral H+/CO2 receptors that control the acid-base status of the blood.  相似文献   
67.
We describe the clinical course and treatment of a 58-year-old male with a primary cardiogenic shock, who underwent a minimally invasive off-pump ventricular-assist-device (VAD) implantation with the aid of paravertebral regional analgesia. He was extubated soon after the procedure, in the operating room, with the aim to reduce the right ventricle impairment. We illustrate how a minimally invasive implant may improve the clinical outcomes of VAD patients shortening their return time to active life.  相似文献   
68.
Primary systemic amyloidosis is a relatively uncommon disease characterized by the production and deposition of pathological insoluble fibrillar proteins in organs and tissues. It has been estimated that between one-third and one-half of all patients with primary amyloidosis experience clinically significant cardiac involvement. The present study reports a case involving a 77-year-old woman with ischemic heart disease who presented to the cardiology department because of syncope due to slow atrial fibrillation. Laboratory tests revealed a monoclonal spike in the gamma fraction and impairment of renal function, normocytic anemia, mild hypercalcemia, hypoalbuminemia and increased levels of beta-2 microglobulin. Suspicion of cardiac involvement was supported by the echocardiographic pattern and increased levels of troponin I and brain natriuretic peptide, along with clinical signs of heart failure and systemic amyloidosis diagnosis, confirmed by abdominal fat aspiration.  相似文献   
69.
We report the follow-up of 47 patients with penile hypospadias who were treated by the Scuderi procedure between 1988 and 1998 at Sahlgrenska University Hospital, Göteborg, Sweden. Forty of the patients (85%) had had no previous operations, while the remaining seven had had meatotomy with chordectomy only, or an unsuccessful Dennis-Browne procedure. Hypospadias was distal in 35 (74%), mediopenile in 8 (17%), and proximal in 4 (9%); 21 (45%) showed signs of curvature. After a Scuderi urethroplasty one patient developed a fistula (2%) and 4 developed mild stenosis. The early success rate was therefore 42/47 (89%) and this later increased to 46/47 (98%) after non-surgical treatment of the stenoses. The results support the use of the Scuderi procedure for correction of primary and secondary penile hypospadias with a low complication rate.  相似文献   
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