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   346868篇
  免费   28963篇
  国内免费   4140篇
耳鼻咽喉   3840篇
儿科学   9316篇
妇产科学   9507篇
基础医学   94713篇
口腔科学   11664篇
临床医学   25219篇
内科学   55316篇
皮肤病学   11916篇
神经病学   18151篇
特种医学   10658篇
外国民族医学   75篇
外科学   44839篇
综合类   10973篇
现状与发展   19篇
一般理论   21篇
预防医学   7064篇
眼科学   3931篇
药学   10376篇
  26篇
中国医学   571篇
肿瘤学   51776篇
  2023年   6006篇
  2022年   9223篇
  2021年   11073篇
  2020年   11021篇
  2019年   8052篇
  2018年   10007篇
  2017年   10141篇
  2016年   10598篇
  2015年   12174篇
  2014年   21340篇
  2013年   19328篇
  2012年   15276篇
  2011年   16320篇
  2010年   17065篇
  2009年   16000篇
  2008年   12662篇
  2007年   12919篇
  2006年   11819篇
  2005年   11002篇
  2004年   10007篇
  2003年   9485篇
  2002年   9281篇
  2001年   9299篇
  2000年   8899篇
  1999年   8418篇
  1998年   5149篇
  1997年   4311篇
  1996年   4347篇
  1995年   3784篇
  1994年   3375篇
  1993年   3113篇
  1992年   6500篇
  1991年   6383篇
  1990年   6246篇
  1989年   5902篇
  1988年   5742篇
  1987年   3357篇
  1986年   1815篇
  1985年   2034篇
  1984年   1925篇
  1983年   1680篇
  1982年   1594篇
  1981年   1397篇
  1980年   1335篇
  1979年   1261篇
  1978年   1188篇
  1977年   955篇
  1976年   859篇
  1974年   889篇
  1973年   854篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
The effect of tobacco smoking on foot and ankle procedures is likely to be more pronounced when compared to other orthopaedic surgery. This is due to the peripheral nature of the vasculature involved. This paper reviews the current clinical evidence on the effects of smoking foot and ankle surgery. In the trauma setting, the evidence suggests that wound complications and non-unions are significantly higher in the smoking population. In the elective setting there is a significantly increased risk of non-union in ankle and hindfoot arthrodeses in smokers. In the setting of diabetes, ulceration rate in smokers is higher and there may be a higher risk of amputation.  相似文献   
53.
54.
55.
Tumor tissue is composed of tumor cells and tumor stroma. Tumor stroma contains various immune cells and non-immune stromal cells, forming a complex tumor microenvironment which plays pivotal roles in regulating tumor growth. Recent successes in immunotherapies against tumors, including immune checkpoint inhibitors, have further raised interests in the immune microenvironment of liver carcinoma. The immune microenvironment of tumors is formed because of interactions among tumor cells, immune cells and non-immune stromal cells, including fibroblasts and endothelial cells. Different patterns of immune microenvironment are observed among different tumor subtypes, and their clinicopathological significance and intertumor/intratumor heterogeneity are being intensively studied. Here, we review the immune microenvironment of hepatocellular carcinoma, intrahepatic cholangiocarcinoma and liver metastasis of colorectal adenocarcinoma, focusing on its histopathological appearance, clinicopathological significance, and relationship with histological and molecular classifications. Understanding the comprehensive histopathological picture of a tumor immune microenvironment, in addition to molecular and genetic approaches, will further potentiate the effort for precision medicine in the era of tumor-targeting immunotherapy.  相似文献   
56.
57.
58.
ObjectivesMap regional lymph node metastases for lateralized oral cavity squamous cell carcinoma (OCSCC) and evaluate factors associated with regional metastases and recurrence.Materials and methodsRetrospective cohort study of 715 patients with lateralized OCSCC surgically treated in 1997–2011. Analysis was performed using log-rank, Kaplan-Meier, and multivariable logistic and Cox regression.ResultsRegional metastases were identified in ipsilateral levels IIA (24%), IB (18%), III (13%), V (9%), IV (7%), IA (2%) and IIB (1%) and the contralateral neck (3%). Lymphovascular invasion (LVI) (Hazard Ratio [HR] 2.2, 95% Confidence Interval [CI] 1.2–3.9) and T category (T3 vs. T1: HR 4.1, 95% CI 1.9–9.3; T4 vs. T1: HR 2.3, 95% CI 1.2–4.3) were associated with regional metastases. Most (71%) isolated regional metastatic recurrences were in undissected levels of the neck, including 58% in levels IV and V. Tumors of the hard palate (HR 4.3, 95% CI 1.2–16.1), upper alveolus (HR 3.2, 95% CI 1.0–4.7) or with LVI (HR 2.0, 95% CI 1.0–3.9) were associated with isolated regional recurrence. For upper alveolar/hard palate tumors, depth of invasion (DOI) ≥4 mm (P = .003) and LVI (P = .04) were associated with regional metastases.ConclusionsFor lateralized OCSCC, elective neck dissection of level IIB or the contralateral neck may rarely be needed, but additional surgical or radiation treatment of levels IV and V may be considered based on patient risk factors, including T category 3–4 or LVI. For upper alveolar/hard palate tumors, DOI ≥4 mm is an appropriate threshold for elective neck dissection.  相似文献   
59.
《Vaccine》2022,40(44):6431-6444
This is a Brighton Collaboration case definition of thrombosis and thromboembolism to be used in the evaluation of adverse events following immunization, and for epidemiologic studies for the assessment of background incidence or hypothesis testing. The case definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of SARS-CoV-2 vaccines. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and defined levels of certainty, after an exhaustive review of the literature and expert consultation. The document underwent peer review by the Brighton Collaboration Network and by selected expert reviewers prior to submission.  相似文献   
60.
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