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   4382590篇
  免费   352246篇
  国内免费   14755篇
耳鼻咽喉   60901篇
儿科学   141063篇
妇产科学   115348篇
基础医学   670979篇
口腔科学   119148篇
临床医学   399813篇
内科学   793309篇
皮肤病学   108309篇
神经病学   372800篇
特种医学   170945篇
外国民族医学   754篇
外科学   662712篇
综合类   121933篇
现状与发展   24篇
一般理论   2720篇
预防医学   361213篇
眼科学   102575篇
药学   311692篇
  22篇
中国医学   12140篇
肿瘤学   221191篇
  2021年   55568篇
  2020年   36216篇
  2019年   59412篇
  2018年   75299篇
  2017年   57345篇
  2016年   63566篇
  2015年   76450篇
  2014年   110972篇
  2013年   176972篇
  2012年   129408篇
  2011年   134925篇
  2010年   127794篇
  2009年   129175篇
  2008年   120572篇
  2007年   128420篇
  2006年   136793篇
  2005年   130906篇
  2004年   131937篇
  2003年   121909篇
  2002年   110965篇
  2001年   167367篇
  2000年   162353篇
  1999年   149081篇
  1998年   72053篇
  1997年   67873篇
  1996年   65551篇
  1995年   60662篇
  1994年   54706篇
  1993年   50710篇
  1992年   106380篇
  1991年   101440篇
  1990年   97201篇
  1989年   94764篇
  1988年   87043篇
  1987年   85242篇
  1986年   80113篇
  1985年   78325篇
  1984年   65226篇
  1983年   57909篇
  1982年   46878篇
  1981年   43517篇
  1980年   40700篇
  1979年   54853篇
  1978年   44506篇
  1977年   39608篇
  1976年   36533篇
  1975年   36547篇
  1974年   39456篇
  1973年   37654篇
  1972年   35334篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
101.
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   
102.
Abstract

Oocyte maturation defect is a challenging situation in the management of infertility, the etiology may be related to endocrine causes, protocols used in ovarian stimulation, oocyte intrinsic defects or procedures in embryology laboratory. We report three Mexican females in treatment for primary infertility with non-mature oocytes after ovary stimulation and oocyte capture in whom a genetic diagnosis of TUBB8-oocyte maturation defect was revealed by exome sequencing. Two couples achieved pregnancies though oocyte donation after establishing the genetic etiology. Our results expand the role of TUBB8-disorders in patients of non-Asian ethnicity. Oocyte maturation defects of monogenic origin are a growing group of disorders that endocrinologists and reproductive medicine specialists should be aware in order to provide referral to genetics for establish a correct and opportune diagnosis.  相似文献   
103.
Aims. Functional connectivity is providing new insights into the network nature of epilepsy with growing clinical applications. Our objective was to validate a novel magnetoencephalography‐based method to non‐invasively measure the epileptic network. Methods. We retrospectively identified pediatric and adult patients with refractory focal epilepsy who underwent pre‐surgical magnetoencephalography with subsequent intracranial electrographic monitoring. Magnetoencephalography tracings were visually reviewed, and interictal epileptiform discharges (“spikes”) were individually marked. We then evaluated differences in whole‐brain connectivity during brief epochs preceding the spikes and during the spikes using the Network‐Based Statistic to test differences at the network level. Results. In six patients with statistically‐significant network differences, we observed substantial overlap between the spike‐associated networks and electrographically active areas identified during intracranial monitoring (the spike‐associated network was 78% and 83% sensitive for intracranial electroencephalography‐defined regions in the irritative and seizure onset zones, respectively). Conclusion. These findings support the neurobiological validity of the spike‐associated network method. Assessment of spike‐associated networks has the potential to improve surgical planning in epilepsy surgery patients by identifying components of the epileptic network prior to implantation.  相似文献   
104.
105.
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   
106.
107.
108.
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   

109.
110.
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