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   3050711篇
  免费   275725篇
  国内免费   13867篇
耳鼻咽喉   42895篇
儿科学   96976篇
妇产科学   76682篇
基础医学   493602篇
口腔科学   81901篇
临床医学   281005篇
内科学   527682篇
皮肤病学   88982篇
神经病学   263310篇
特种医学   120214篇
外国民族医学   100篇
外科学   487328篇
综合类   93974篇
现状与发展   91篇
一般理论   2115篇
预防医学   253122篇
眼科学   70842篇
药学   205430篇
  18篇
中国医学   9724篇
肿瘤学   144310篇
  2021年   54558篇
  2020年   37320篇
  2019年   58532篇
  2018年   73376篇
  2017年   56286篇
  2016年   61953篇
  2015年   76387篇
  2014年   113139篇
  2013年   177974篇
  2012年   82503篇
  2011年   80812篇
  2010年   117972篇
  2009年   124302篇
  2008年   68111篇
  2007年   68962篇
  2006年   81088篇
  2005年   75451篇
  2004年   77373篇
  2003年   68125篇
  2002年   58192篇
  2001年   86411篇
  2000年   77987篇
  1999年   81549篇
  1998年   64505篇
  1997年   62467篇
  1996年   59684篇
  1995年   54728篇
  1994年   48730篇
  1993年   45351篇
  1992年   54245篇
  1991年   52498篇
  1990年   49391篇
  1989年   49559篇
  1988年   45695篇
  1987年   44503篇
  1986年   42319篇
  1985年   42805篇
  1984年   40867篇
  1983年   37841篇
  1982年   38544篇
  1981年   36575篇
  1980年   34543篇
  1979年   32542篇
  1978年   30490篇
  1977年   28228篇
  1976年   25936篇
  1975年   24602篇
  1974年   24444篇
  1973年   23353篇
  1972年   21937篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
101.
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   
102.
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   
103.
104.
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   
105.
106.
107.
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   

108.
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