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   4811698篇
  免费   376899篇
  国内免费   15405篇
耳鼻咽喉   67583篇
儿科学   151499篇
妇产科学   126673篇
基础医学   726948篇
口腔科学   134668篇
临床医学   440620篇
内科学   875936篇
皮肤病学   115793篇
神经病学   403576篇
特种医学   187213篇
外国民族医学   833篇
外科学   728431篇
综合类   131585篇
现状与发展   24篇
一般理论   2774篇
预防医学   395185篇
眼科学   113449篇
药学   344383篇
  25篇
中国医学   13023篇
肿瘤学   243781篇
  2021年   56903篇
  2019年   59454篇
  2018年   75949篇
  2017年   57963篇
  2016年   64280篇
  2015年   76896篇
  2014年   111399篇
  2013年   177247篇
  2012年   137099篇
  2011年   143870篇
  2010年   130018篇
  2009年   130656篇
  2008年   129979篇
  2007年   138838篇
  2006年   146734篇
  2005年   140508篇
  2004年   141248篇
  2003年   131003篇
  2002年   120114篇
  2001年   193130篇
  2000年   189426篇
  1999年   171203篇
  1998年   74920篇
  1997年   69741篇
  1996年   67808篇
  1995年   63170篇
  1994年   57009篇
  1993年   52856篇
  1992年   124992篇
  1991年   119276篇
  1990年   114940篇
  1989年   111868篇
  1988年   102940篇
  1987年   100882篇
  1986年   95032篇
  1985年   92682篇
  1984年   75199篇
  1983年   66388篇
  1982年   50403篇
  1981年   46594篇
  1980年   43584篇
  1979年   64799篇
  1978年   50711篇
  1977年   45163篇
  1976年   41428篇
  1975年   42158篇
  1974年   46464篇
  1973年   44299篇
  1972年   41601篇
  1971年   38634篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
Maternal and Child Health Journal - Early life exposures can have an impact on a child’s developmental trajectory and children born late preterm (34–36 weeks gestational age)...  相似文献   
92.
93.
Troppmair  Teresa  Egger  J.  Krösbacher  A.  Zanvettor  A.  Schinnerl  A.  Neumayr  A.  Baubin  M. 《Der Anaesthesist》2022,71(4):272-280
Die Anaesthesiologie - Die Qualität eines Rettungssystems zeichnet sich auch durch den effizienten Einsatz seiner personellen und Fahrzeugressourcen aus. So können im berechtigten Fall...  相似文献   
94.
95.
Cutaneous leiomyomas are rare benign smooth‐muscle tumors. These lesions are distinguished based on their cell of origin and are subclassified as pilar leiomyoma, angioleiomyoma, and genital‐type leiomyoma. Nipple leiomyoma is the least common genital‐type leiomyoma, arising from the dartoic muscle cell of the nipple. Histologic examination of the lesion is necessary for definitive diagnosis, and these uncommon tumors can pose a diagnostic challenge. We describe herein a series of six nipple leiomyomas with a spectrum of histologic appearances.  相似文献   
96.
97.
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   
98.
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   

99.
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   
100.
目的:探讨健脾益肾方对非小细胞肺癌(NSCLC)细胞体外增殖凋亡的作用。方法:人NSCLC细胞系A549分为四组:空白对照组(仅加入细胞培养液)、阴性对照组(加入细胞,不进行中药处理)、实验组(加细胞加中药处理)。荧光定量PCR和Western blot分别检测Survivin、Bcl-2和Caspase-3的mRNA和蛋白表达。MTT检测细胞增殖;流式细胞术检测细胞凋亡。结果:与空白对照组相比,阴性对照组细胞在24、48、72 h的吸光度值明显升高,细胞凋亡率下降,Survivin和Bcl-2 mRNA和蛋白相对表达量上调,Caspase-3 mRNA和蛋白相对表达量下调,组间比较差异有统计学意义(P<0.05);而健脾益肾方处理的实验组24、48、72 h的吸光度值均显著降低,细胞凋亡率显著上升,Survivin和Bcl-2 mRNA和蛋白相对表达量下调,Caspase-3 mRNA和蛋白相对表达量上调,与空白对照组相比差异有统计学意义(P<0.05)。结论:健脾益肾方可通过下调Survivin和Bcl-2、上调Caspase-3表达诱导NSCLC细胞凋亡,并抑制肿瘤细胞的增殖,进而抑制NSCLC的发展。  相似文献   
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