首页 | 官方网站   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   65017篇
  免费   5905篇
  国内免费   2772篇
医药卫生   73694篇
  2024年   90篇
  2023年   942篇
  2022年   1247篇
  2021年   2980篇
  2020年   2095篇
  2019年   2305篇
  2018年   2809篇
  2017年   2106篇
  2016年   1968篇
  2015年   2751篇
  2014年   3262篇
  2013年   3460篇
  2012年   5359篇
  2011年   5688篇
  2010年   3333篇
  2009年   2708篇
  2008年   3896篇
  2007年   3854篇
  2006年   3783篇
  2005年   3447篇
  2004年   2718篇
  2003年   2362篇
  2002年   2054篇
  2001年   1053篇
  2000年   1009篇
  1999年   1007篇
  1998年   678篇
  1997年   628篇
  1996年   513篇
  1995年   439篇
  1994年   437篇
  1993年   303篇
  1992年   321篇
  1991年   263篇
  1990年   213篇
  1989年   283篇
  1988年   218篇
  1987年   197篇
  1986年   135篇
  1985年   139篇
  1984年   89篇
  1983年   68篇
  1982年   63篇
  1981年   70篇
  1980年   58篇
  1979年   52篇
  1978年   31篇
  1977年   31篇
  1976年   32篇
  1974年   29篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
1.
中医学古籍中罕有关于“胰腺”的明确记载,缺乏直观、系统的理论论述。本文试图通过对各个时期具有代表性的医学典籍所记载内容的分析,结合现代解剖学相关理论,梳理中医学对胰腺实体解剖的认识过程。通过分析,笔者认为中医学对胰腺实体解剖的认识具有阶段性:①先秦两汉时期,存在胰腺实体解剖,但并非认为胰腺是脏器;②唐宋时期,胰腺实体解剖更加清晰,在医学上胰腺附属于脾,并非为独立的脏器;③明清时期,胰腺实体解剖明确,部分医家以独立脏器论之,出现“脾”、“胰”之争。中医学理论缺少对胰腺的单独论述,目前学界的主流观点多为“胰属脾”,线性归属以脾笼统代之略显单薄,不利于理论的丰富与发展。笔者认为胰腺藏象应独立于脾单独讨论,现代解剖学对胰腺命名同一,形态结构清楚,位置描述明确,可直接补充进中医学胰腺藏象(藏)理论中,为完善胰腺藏象理论搭建解剖学基础。  相似文献   
2.
3.
4.
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   
5.
MicroRNAs (miRNAs) play important roles in prostate cancer development. However, it remains unclear how individual miRNAs contribute to the initiation and progression of prostate cancer. Here we show that a basal layer‐enriched miRNA is required for prostate tumorigenesis. We identify miR‐205 as the most highly expressed miRNA and enriched in the basal cells of the prostate. Although miR‐205 is not required for normal prostate development and homeostasis, genetic deletion of miR‐205 in a Pten null tumor model significantly compromises tumor progression and does not promote metastasis. In Pten null basal cells, loss of miR‐205 attenuates pAkt levels and promotes cellular senescence. Furthermore, although overexpression of miR‐205 in prostate cancer cells with luminal phenotypes inhibits cell growth in both human and mouse, miR‐205 has a minimal effect on the growth of a normal human prostate cell line. Taken together, we have provided genetic evidence for a requirement of miR‐205 in the progression of Pten null‐induced prostate cancer.  相似文献   
6.
miRNAs是一类长度约为20~25个核苷酸,参与基因调控表达的内源性非编码RNA。miR-149作为miRNAs的重要成员,在多种肿瘤中表达异常,其表达水平与肿瘤细胞增殖、转移、凋亡、耐药、患者的早期诊断及预后密切相关。因此,miR-149有望成为新一类抗肿瘤治疗的靶点。  相似文献   
7.
8.
患者男,64岁,因头颅增大、面部变长,颧骨隆起、下颌增大、双手掌肥厚、双手指粗短30余年,乳房肿物1年余就诊。患者30余年前无明显诱因出现渐进性手足增大,双手掌肥厚,嘴唇变厚,下颌增大,眉弓及颧骨突出,皮肤增厚,无乳腺增大、泌乳,未诊治……  相似文献   
9.
10.
Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.  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-23

京公网安备 11010802026262号