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   5608篇
  免费   448篇
  国内免费   10篇
耳鼻咽喉   37篇
儿科学   273篇
妇产科学   163篇
基础医学   743篇
口腔科学   131篇
临床医学   862篇
内科学   1089篇
皮肤病学   76篇
神经病学   453篇
特种医学   89篇
外科学   419篇
综合类   106篇
一般理论   7篇
预防医学   793篇
眼科学   133篇
药学   335篇
中国医学   6篇
肿瘤学   351篇
  2023年   27篇
  2022年   45篇
  2021年   101篇
  2020年   64篇
  2019年   105篇
  2018年   119篇
  2017年   82篇
  2016年   117篇
  2015年   121篇
  2014年   149篇
  2013年   239篇
  2012年   301篇
  2011年   369篇
  2010年   187篇
  2009年   185篇
  2008年   306篇
  2007年   335篇
  2006年   368篇
  2005年   395篇
  2004年   348篇
  2003年   349篇
  2002年   325篇
  2001年   44篇
  2000年   46篇
  1999年   69篇
  1998年   65篇
  1997年   56篇
  1996年   46篇
  1995年   44篇
  1994年   31篇
  1993年   42篇
  1992年   32篇
  1991年   38篇
  1990年   47篇
  1989年   33篇
  1988年   39篇
  1986年   28篇
  1985年   28篇
  1984年   30篇
  1983年   47篇
  1982年   48篇
  1981年   47篇
  1980年   29篇
  1979年   31篇
  1978年   24篇
  1977年   32篇
  1975年   23篇
  1974年   26篇
  1973年   30篇
  1971年   21篇
排序方式: 共有6066条查询结果,搜索用时 15 毫秒
1.
Patient navigation is a strategy for overcoming barriers to reduce disparities and to improve access and outcomes. The aim of this umbrella review was to identify, critically appraise, synthesize, and present the best available evidence to inform policy and planning regarding patient navigation across the cancer continuum. Systematic reviews examining navigation in cancer care were identified in the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Cumulative Index of Nursing and Allied Health (CINAHL), Epistemonikos, and Prospective Register of Systematic Reviews (PROSPERO) databases and in the gray literature from January 1, 2012, to April 19, 2022. Data were screened, extracted, and appraised independently by two authors. The JBI Critical Appraisal Checklist for Systematic Review and Research Syntheses was used for quality appraisal. Emerging literature up to May 25, 2022, was also explored to capture primary research published beyond the coverage of included systematic reviews. Of the 2062 unique records identified, 61 systematic reviews were included. Fifty-four reviews were quantitative or mixed-methods reviews, reporting on the effectiveness of cancer patient navigation, including 12 reviews reporting costs or cost-effectiveness outcomes. Seven qualitative reviews explored navigation needs, barriers, and experiences. In addition, 53 primary studies published since 2021 were included. Patient navigation is effective in improving participation in cancer screening and reducing the time from screening to diagnosis and from diagnosis to treatment initiation. Emerging evidence suggests that patient navigation improves quality of life and patient satisfaction with care in the survivorship phase and reduces hospital readmission in the active treatment and survivorship care phases. Palliative care data were extremely limited. Economic evaluations from the United States suggest the potential cost-effectiveness of navigation in screening programs.  相似文献   
2.
3.
Digital radiography is an appropriate method for both bedside and in-department chest radiographs. Its major advantage in bedside chest radiography is its control of the displayed optical density of these radiographs. With dynamic range control processing, it improves the visibility of tubes and lines superimposed on the mediastinal tissues. When used for in-department chest radiography, it may offer slight advantages in the evaluation of disease in the mediastinum, but in general is equivalent to film-screen chest radiography. The main reasons for using digital chest radiography for in-department chest radiographs relate mainly to its use as a data entry point method of projection radiography for high-quality teleradiology or for its use in a picture archiving and communication system. Apart from these advantages, there is no reason to change from conventional to digital chest radiographs. Digital radiographs are, with certain systems, printed at smaller than life size. Because of this, there is a necessary period of learning as radiologists adjust to the new image size. The most important change in radiologists' work pattern appears to be the need to sit closer to the film. Findings of disease are smaller, but, with experience, just as easy to see.  相似文献   
4.
Management of splenic injuries in children has evolved over the past two decades. Splenectomies or splenorrhaphies are now performed infrequently, with the majority of hemodynamically stable children with splenic injuries managed nonoperatively. This article reviews the imaging features of acute splenic injuries in children as well as the appearance of healing splenic injuries. Follow-up evaluation and outcomes in children with splenic injuries also are addressed.  相似文献   
5.
Gastrogastric fistula: a possible complication of Roux-en-Y gastric bypass.   总被引:4,自引:0,他引:4  
BACKGROUND: Gastrogastric fistula is a communication between the proximal gastric pouch and the distal gastric remnant, rarely described in the realm of bariatric procedures. The aim of this study was to review the existing literature about this topic and to demonstrate its laparoscopic treatment. METHODS: An extensive literature review found several articles reporting this complication. However, no citation was found describing the steps of the laparoscopic management of this situation. RESULTS: Gastrogastric fistula occurs in up to 6% of Roux-en-Y gastric bypasses. Two theories exist for fistula formation: (1) it is a technical complication derived from the incomplete division of the stomach during the creation of the pouch, and (2) it occurs after a staple-line failure, developing a leak with an abscess, which then drains into the distal stomach forming the fistula. Early symptoms include fever, tachycardia, and abdominal pain. Failure in weight loss is a late clinical sign observed in these patients. Diagnosis is based on radiologic study, upper endoscopy and computed tomography. When identified in the acute postoperative course, laparoscopic treatment is easy. Chronic fistulas are difficult to manage, and the laparoscopic approach is an alternative to open surgery. CONCLUSIONS: Gastrogastric fistula is a possible complication of Roux-en-Y gastric bypass and its laparoscopic treatment is feasible.  相似文献   
6.
A 66‐year‐old woman developed firm, painless, slowly growing nodular masses over her elbows, fingers, toes, and left hip over four years. Aspiration of the elbow mass revealed a white chalky material that was shown to be carbonate apatite on infrared spectroscopy and energy dispersive X‐ray spectroscopy. We discuss the classification of tumoral calcinosis and the nature of the calcium deposits. Tumoral calcinosis should be differentiated from tophaceous gout and calcium pyrophosphate dihydrate crystal deposition disease. Polarizing light microscopy and crystal analysis by X‐ray and infrared spectroscopy, electron or X‐ray diffraction will confirm the diagnosis. Secondary causes of tumoral calcinosis should also be excluded.  相似文献   
7.
Wound assessment is a key element of effective wound care, and assessment of pressure ulcers includes accurate determination of wound stage. Although the original staging system established by Shea was based on his understanding of the pathology involved in pressure ulcer development, subsequent staging systems (and the one currently in use) were intended simply to establish the level of tissue damage. Recently, clinicians have drawn attention to numerous limitations associated with the current staging system, including the inability to differentiate between an inflammatory response involving intact skin and a deep tissue injury (deep bruising) underneath intact skin. This is a clinically significant difference because clinicians have noted that most inflammatory responses resolve with intervention, whereas most areas of deep tissue injury progress to full-thickness ulcers even when appropriate intervention is provided. A second area of controversy involves partial-thickness (Stage 2) lesions; because many of these lesions are caused by maceration and/or friction (as opposed to pressure) clinicians are frequently unclear regarding which of these lesions should be staged. In response to these concerns, the National Pressure Ulcer Advisory Panel convened a consensus forum and published white papers to clearly outline the issues; they solicited clinician feedback on the white papers and the Wound, Ostomy, Continence Nurses Society provided a written response. This article summarizes the key points of the white papers, WOCN Society response, and consensus forum discussion.  相似文献   
8.
Recovery from fast inactivation in voltage-dependent Na+ channels is associated with a slow component in the time course of gating charge during repolarization (i.e. charge immobilization), which results from the slow movement of the S4 segments in domains III and IV (S4-DIII and S4-DIV). Previous studies have shown that the non-specific removal of fast inactivation by the proteolytic enzyme pronase eliminated charge immobilization, while the specific removal of fast inactivation (by intracellular MTSET modification of a cysteine substituted for the phenylalanine in the IFM motif, ICMMTSET, in the inactivation particle formed by the linker between domains III and IV) only reduced the amount of charge immobilization by nearly one-half. To investigate the molecular origin of the remaining slow component of charge immobilization we studied the human cardiac Na+ channel (hH1a) in which the outermost arginine in the S4-DIV, which contributes ∼20% to total gating charge ( Q max), was mutated to a cysteine (R1C-DIV). Gating charge could be fully restored in R1C-DIV by exposure to extracellular MTSEA, a positively charged methanethiosulphonate reagent. The RIC-DIV mutation was combined with ICMMTSET to remove fast inactivation, and the gating currents of R1C-DIV-ICMMTSET were recorded before and after modification with MTSEAo. Prior to MTSEAo, the time course of the gating charge during repolarization ( off -charge) was best described by a single fast time constant. After MTSEA, the off -charge had both fast and slow components, with the slow component accounting for nearly 35% of Q max. These results demonstrate that the slow movement of the S4-DIV during repolarization is not dependent upon the normal binding of the inactivation particle.  相似文献   
9.
Image processing is a critical part of obtaining high-quality digital radiographs. Fortunately, the user of these systems does not need to understand image processing in detail, because the manufacturers provide good starting values. Because radiologists may have different preferences in image appearance, it is helpful to know that many aspects of image appearance can be changed by image processing, and a new preferred setting can be loaded into the computer and saved so that it can become the new standard processing method.Image processing allows one to change the overall optical density of an image and to change its contrast. Spatial frequency processing allows an image to be sharpened, improving its appearance. It also allows noise to be blurred so that it is less visible. Care is necessary to avoid the introduction of artifacts or the hiding of mediastinal tubes.  相似文献   
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