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   2803888篇
  免费   247291篇
  国内免费   15173篇
耳鼻咽喉   38550篇
儿科学   84521篇
妇产科学   70666篇
基础医学   463995篇
口腔科学   75495篇
临床医学   247431篇
内科学   483729篇
皮肤病学   80117篇
神经病学   243783篇
特种医学   109734篇
外国民族医学   108篇
外科学   445185篇
综合类   91048篇
现状与发展   24篇
一般理论   2050篇
预防医学   229383篇
眼科学   64079篇
药学   193157篇
  23篇
中国医学   9810篇
肿瘤学   133464篇
  2022年   22742篇
  2021年   54463篇
  2020年   34793篇
  2019年   57668篇
  2018年   69431篇
  2017年   52826篇
  2016年   58242篇
  2015年   73111篇
  2014年   107160篇
  2013年   172017篇
  2012年   73214篇
  2011年   69585篇
  2010年   110926篇
  2009年   117126篇
  2008年   57094篇
  2007年   57647篇
  2006年   69450篇
  2005年   64625篇
  2004年   66864篇
  2003年   58413篇
  2002年   48435篇
  2001年   78922篇
  2000年   70489篇
  1999年   75690篇
  1998年   62641篇
  1997年   61049篇
  1996年   58145篇
  1995年   53637篇
  1994年   47718篇
  1993年   44739篇
  1992年   49295篇
  1991年   45855篇
  1990年   42682篇
  1989年   43116篇
  1988年   39869篇
  1987年   38750篇
  1986年   36539篇
  1985年   37284篇
  1984年   36952篇
  1983年   34686篇
  1982年   37562篇
  1981年   35672篇
  1980年   33670篇
  1979年   28039篇
  1978年   27383篇
  1977年   26145篇
  1976年   23241篇
  1975年   21229篇
  1974年   20168篇
  1973年   19209篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100?nm) and their implications on intestinal epithelial permeability in vitro. Au NPs aggregated in fasted gastric fluids and generated hydroxyl radicals in the presence of H2O2. Cell studies showed that GIT fluids incubation of Au NPs affected the cellular uptake of Au NPs but did not induce cytotoxicity or disturb the intestinal epithelial permeability.  相似文献   
93.
Introduction: The Hedgehog (HH) pathway constitutes a collection of signaling molecules which critically influence embryogenesis. In adults, however, the HH pathway remains integral to the proliferation, maintenance, and apoptosis of adult stem cells including hematopoietic stem cells.

Areas covered: We discuss the current understanding of the HH pathway as it relates to normal hematopoiesis, the pathology of acute myeloid leukemia (AML), the rationale for and data from combination therapies including HH pathway inhibitors, and ultimately the prospects that might offer promise in targeting this pathway in AML.

Expert opinion: Efforts to target the HH pathway have been focused on impeding this disposition and restoring chemosensitivity to conventional myeloid neoplasm therapies. The year 2018 saw the first approval of a HH pathway inhibitor (glasdegib) for AML, though for an older population and in combination with an uncommonly-used therapy. Several other clinical trials with agents targeting modulators of HH signaling in AML and MDS are underway. Further study and understanding of the interplay between the numerous aspects of HH signaling and how it relates to the augmented survival of AML will provide a more reliable substrate for therapeutic strategies in patients with this poor-risk disease.  相似文献   

94.
Adjuvant irradiation is the standard treatment after breast conservative surgery. Normofractionated regimen with an overall treatment time of 5 to 6 weeks is often considered as a limiting factor for irradiation compliance. In order to answer this issue, moderate and more recently extreme hypofractionated protocols appeared. We report here oncological outcomes and toxicity of hypofractionated breast irradiation. After defining the frame of moderate and extreme hypofractionated breast irradiations based on overall treatment time, patient selection criteria were listed. According to their levels of proof, the results of moderate and extreme hypofractionated breast irradiation were analysed. Overall treatment time for moderate hypofractionated breast irradiation ranged from 3 to 4 weeks, while for extreme hypofractionated breast irradiation, it was less than 1 week. For moderate hypofractionated breast irradiation, whole breast irradiation was currently performed with or without lymph node irradiation. Moderate hypofractionated breast irradiation has proven to be as safe and as efficient as normofractionated breast irradiation with level IA evidence. For extreme hypofractionated breast irradiation, phase III randomized trials confirmed that accelerated partial breast irradiation was non-inferior in terms of local control compared to normofractionated whole breast irradiation (with external beam radiation therapy and multicatheter brachytherapy), with similar acute and late toxicity. While the use of intraoperative breast irradiation remains under debate, new very accelerated partial breast irradiation (overall treatment time not exceeding 2 days) protocols emerged with encouraging results. Accelerated partial breast irradiation is warranted for extreme hypofractionated breast irradiation and is indicated for low-risk breast cancers. Moderate and extreme hypofractionated breast irradiation regimens are validated and can be routinely proposed according to patient selection criteria.  相似文献   
95.
ABSTRACT

Objective: Dry eye is reported to be associated with several neurological diseases. The aim of this study is to evaluate the patients with hemiplegia after stroke for dry eye and compare their results with a control group.

Materials and methods: Forty-five patients with hemiplegia and 45 individuals as the control group were included in the study. Tear function tests (Schirmer and tear breakup time) and a dry eye questionnaire for dry eye symptoms (ocular surface disease index) were performed and the results of the two groups were compared.

Results: Schirmer test results were significantly lower in the post-stroke hemiplegia group compared to the control group (11.3 ± 8.2 mm and 20.6 ± 11.6 mm, respectively, p < .001). Tear breakup time results were significantly lower in the post-stroke hemiplegia group compared to the control group (7.9 ± 3.1 s and 12.1 ± 4.3 s, respectively, p < .001). Ocular surface disease index scores were not significantly different between hemiplegia and control groups (21.6 ± 20.0 and 19.8 ± 13.9, respectively, p = .635). Schirmer scores lower than 10 mm (60% and 30%, p < .001) and tear breakup time results lower than 10 s (65.6% and 28.9%, p < .001) were also higher in the hemiplegia group compared to control group.

Conclusion: We found lower Schirmer test and tear breakup time results and similar OSDI scores in hemiplegia patients compared to controls. Hemiplegia patients may have dry eye without typical symptoms. This should be taken into consideration in the follow-up and rehabilitation of post-stroke hemiplegia patients.  相似文献   
96.
97.
Introduction: Percutaneous renal mass biopsy has evolved over the last decade with improvements on previous pitfalls including low tissue yield, high non-diagnostic rates, and complications. As understanding of tumor biology and natural history of renal cortical neoplasms has improved, percutaneous renal mass biopsy is poised to have an expanding role in an area characterized by individualized management and refined risk stratification.

Areas covered: This review summarizes the evolution of renal mass biopsy to its current state with respect to outcomes, indications, and clinical guidelines.

Expert opinion: With improved understanding of differential biological potential of renal cortical neoplasms combined with technical improvements in diagnostic yield and accuracy, utilization of renal mass biopsy is becoming an important adjunct to patient care in a broad range of clinical scenarios, including active surveillance, thermal ablation, and use of primary systemic therapy in localized and advanced settings.  相似文献   

98.
99.
100.
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