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   2263篇
  免费   228篇
  国内免费   12篇
耳鼻咽喉   14篇
儿科学   97篇
妇产科学   18篇
基础医学   253篇
口腔科学   71篇
临床医学   259篇
内科学   449篇
皮肤病学   87篇
神经病学   174篇
特种医学   49篇
外科学   450篇
综合类   55篇
一般理论   5篇
预防医学   138篇
眼科学   120篇
药学   110篇
中国医学   3篇
肿瘤学   151篇
  2023年   15篇
  2022年   34篇
  2021年   62篇
  2020年   41篇
  2019年   67篇
  2018年   57篇
  2017年   49篇
  2016年   42篇
  2015年   58篇
  2014年   79篇
  2013年   83篇
  2012年   120篇
  2011年   137篇
  2010年   87篇
  2009年   65篇
  2008年   125篇
  2007年   148篇
  2006年   132篇
  2005年   145篇
  2004年   142篇
  2003年   114篇
  2002年   112篇
  2001年   13篇
  1999年   11篇
  1998年   26篇
  1997年   21篇
  1996年   18篇
  1995年   19篇
  1994年   16篇
  1992年   16篇
  1990年   15篇
  1989年   18篇
  1988年   14篇
  1987年   13篇
  1986年   24篇
  1985年   11篇
  1984年   14篇
  1983年   28篇
  1982年   17篇
  1981年   22篇
  1980年   12篇
  1977年   14篇
  1976年   11篇
  1975年   14篇
  1974年   14篇
  1973年   11篇
  1963年   12篇
  1962年   12篇
  1961年   14篇
  1960年   21篇
排序方式: 共有2503条查询结果,搜索用时 15 毫秒
61.
62.
The United States Medical Licensing Examination (USMLE®) Steps are a series of mandatory licensing assessments for all allopathic (MD degree) medical students in their transition from student to intern to resident physician. Steps 1, 2 Clinical Knowledge (CK), and 3 are daylong multiple-choice exams that quantify a medical student’s basic science and clinical knowledge as well as their application of that knowledge using a three-digit score. In doing so, these Steps provide a standardized assessment that residency programs use to differentiate applicants and evaluate their competitiveness. Step 2 Clinical Skills (CS), the only other Step exam and the second component of Step 2, was created in 2004 to test clinical reasoning and patient-centered skills. As a Pass/Fail exam without a numerical scoring component, Step 2 CS provides minimal differentiation among applicants for residency programs. In this personal view article, it is argued that the current Step 2 CS exam should be eliminated for US medical students and propose an alternative consistent with the mission and purpose of the exam that imposes less of a burden on medical students.  相似文献   
63.
Colorectal cancer is the second most common cause of death from cancer in the UK. It is estimated that between 2 to 3 per cent of colorectal cancer occurs in patients younger than the age of 40 years. It remains unclear from the literature whether this group of patients has a worse prognosis from colorectal cancer than the population as a whole. There are no large series that report a 10-year survival in young patients diagnosed with colorectal cancer. The authors' objective was to assess patients diagnosed with colorectal cancer younger than the age of 40 years to determine whether the 5- and 10-year survival rates in a tertiary referral center compares favorably with survival rates obtained at other centers and the population as a whole. A retrospective observational study was conducted and an analysis of the patient's notes was made, specifically looking at age at diagnosis, nature and duration of symptoms, predisposing risk factors for colorectal cancer, the site within the bowel of the colorectal cancer, the type of curative resection performed, Dukes' stage, and details of 5- and 10-year follow-up to assess survival. Forty-nine patients age 40 years or younger received treatment for colorectal cancer at St. Mark's Hospital from 1982 to 1992. The overall 5- and 10-year survival was 58 per cent and 46 per cent respectively. The study provides more evidence to support the fact that young patients with colorectal cancer seem to present with more advanced disease. Despite this, the overall 5-year relative survival rate is comparable if not better than other studies, supporting recent evidence that the prognosis in this group of patients is no worse than for colorectal cancer in the population as a whole.  相似文献   
64.
Sarcopenia, or loss of skeletal muscle mass, is associated with increased mortality and morbidity in liver transplant (LT) candidates. Six‐minute walk distance (6MWD) and health‐related quality of life (HRQOL) as assessed by short form 36 scores (SF‐36) also impact clinical outcomes in these patients. This study explored the relationship between the sarcopenia, 6MWD, and HRQOL in LT candidates. Sarcopenia was evaluated based on skeletal muscle mass index (SMI) quantified from abdominal computed tomography. Patients were followed until death, removal from the wait list or the end of the study period. Two hundred and thirteen patients listed for LT were included. The mean SMI, 6MWD and mean gait speed were 54.3 ± 9.7, 370.5 m and 1 m/s, respectively. Sarcopenia was noted in 22.2% of LT candidates. There was no correlation between sarcopenia, 6MWD, and SF‐36 scores. The 6MWD, but not sarcopenia, was an independent predictor of mortality (hazard ratio = 2.1 [0.9–4.7]). In summary, sarcopenia did not emerge as a significant predictor of waitlist mortality and also failed to correlate with either functional capacity or HRQOL in LT candidates. In patients with ESLD awaiting LT, 6MWD appears to be a more useful prognostic indicator than the presence of sarcopenia.  相似文献   
65.
66.
67.
Spindle cell lipoma is strongly CD34 positive. An immunohistochemical study   总被引:2,自引:0,他引:2  
Spindle cell lipoma (SCL) is an uncommon soft tissue neoplasm that may provide diagnostic difficulty to the histopathologist. Four retrospectively identified SCLs were evaluated immunohistochemically with a broad panel of antibodies (CD34, factor XIIIa, S-100, actin and factor VIII). All four SCLs were strongly CD34 positive (95 to 100% of cells) and focally factor XIIIa positive (average 16% of cells). Tumor cells were S-100, actin and factor VIII negative.
Dermatofibrosarcoma protuberans, neurofibroma, schwannoma and angiolipoma are CD34 positive tumors that have some similar histologic features to SCL and may be considered in the differential diagnosis. Differentiation is possible using a broad panel of immunostains and routine diagnostic criteria.  相似文献   
68.
Ischemia-reperfusion plays a major role in the injury experienced by the liver during transplantation. Much work has been done recently investigating the role of redox species in hepatic ischemia-reperfusion. As animal models are better characterized and developed, and more insights are gained into the pathophysiology of hepatic ischemia reperfusion injury in humans the questions into exactly how oxidants participate in this injury are becoming more refined. These questions include effects of cellular location, timing of injury, and ability of therapeutics to access this site are increasing our appreciation of the complexity of ischemia reperfusion and improving attempts to ameliorate its effects. In this review, we aim to discuss the various methods to alter redox chemistry during ischemia reperfusion injury and future prospects for preventing organ injury during hepatic ischemia reperfusion.  相似文献   
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