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   3301篇
  免费   151篇
  国内免费   54篇
耳鼻咽喉   10篇
儿科学   22篇
妇产科学   738篇
基础医学   1053篇
口腔科学   24篇
临床医学   91篇
内科学   259篇
皮肤病学   33篇
神经病学   309篇
特种医学   43篇
外科学   284篇
综合类   187篇
预防医学   94篇
眼科学   10篇
药学   232篇
中国医学   26篇
肿瘤学   91篇
  2024年   4篇
  2023年   47篇
  2022年   47篇
  2021年   116篇
  2020年   85篇
  2019年   80篇
  2018年   77篇
  2017年   71篇
  2016年   82篇
  2015年   79篇
  2014年   131篇
  2013年   181篇
  2012年   108篇
  2011年   161篇
  2010年   151篇
  2009年   124篇
  2008年   147篇
  2007年   128篇
  2006年   157篇
  2005年   135篇
  2004年   124篇
  2003年   110篇
  2002年   114篇
  2001年   85篇
  2000年   95篇
  1999年   75篇
  1998年   59篇
  1997年   65篇
  1996年   64篇
  1995年   80篇
  1994年   62篇
  1993年   61篇
  1992年   51篇
  1991年   42篇
  1990年   47篇
  1989年   41篇
  1988年   32篇
  1987年   35篇
  1986年   26篇
  1985年   28篇
  1984年   19篇
  1983年   15篇
  1982年   19篇
  1981年   15篇
  1980年   5篇
  1979年   6篇
  1978年   4篇
  1977年   10篇
  1976年   3篇
  1975年   2篇
排序方式: 共有3506条查询结果,搜索用时 31 毫秒
1.
《Immunity》2022,55(3):442-458.e8
  1. Download : Download high-res image (213KB)
  2. Download : Download full-size image
  相似文献   
2.
3.
《Journal of thoracic oncology》2020,15(11):1773-1781
IntroductionAnti–programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) antibody therapy is a standard treatment for advanced NSCLC, and PD-L1 immunohistochemistry is used as a predictive biomarker for therapeutic response. However, because not all patients with NSCLC with high PD-L1 respond, and some patients with low PD-L1 expression exhibit durable benefit, more accurate predictive biomarkers are needed. Circulating microRNA (miRNA) and miRNA packaged in extracellular vesicles (EVs) are believed to play a role in intercellular communication among immune cells and between immune cells and tumor cells and may represent a good source of mechanism-related biomarkers.MethodsPretreatment plasma of patients with advanced NSCLC treated with single-agent anti–PD-1 or anti–PD-L1 antibody was used in this study. Plasma EVs were isolated using size-exclusion chromatography. Whole plasma and EV-containing RNAs were extracted. The miRNA profile was analyzed with a next-generation sequencing platform.ResultsSamples from 14 responders (patients who exhibited partial response or stable disease ≥6 mo) and 15 nonresponders (patients who exhibited progressive disease as per Response Evaluation Criteria in Solid Tumors) were analyzed. In total, 32 miRNAs (p = 0.0030–0.0495) from whole plasma and seven EV-associated miRNAs (p = 0.041–0.0457) exhibited significant concentration differences between responders and nonresponders. The results of some of these circulating miRNAs were validated in a separate cohort with eight responders and 13 nonresponders. The tumor PD-L1 level was also assessed using immunohistochemistry for patients involved in both cohorts.ConclusionsSpecific circulating miRNAs in whole plasma and plasma EVs are differentially expressed between responders and nonresponders and have potential as predictive biomarkers for anti–PD-1/PD-L1 treatment response.  相似文献   
4.
B cells are recognized as the main effector cells of humoral immunity which suppress tumor progression by secreting immunoglobulins, promoting T cell response, and killing cancer cells directly. Given these properties, their anti-tumor immune response in the tumor micro-environment (TME) is of great interest. Although T cell-related immune responses have become a therapeutic target with the introduction of immune checkpoint inhibitors, not all patients benefit from these treatments. B cell and B cell-related pathways (CCL19, −21/CCR7 axis and CXCL13/CXCR5 axis) play key roles in activating immune response through humoral immunity and local immune activation via tertiary lymphoid structure (TLS) formation. However they have some protumorigenic works in the TME. Thus, a better understanding of B cell and B cell-related pathways is necessary to develop effective cancer control. In this review, we summarize recent evidences regarding the roles of B cell and B cell-related pathways in the TME and immune response and discuss their potential roles for novel cancer treatment strategies.  相似文献   
5.
6.
The aim of this prospective study was to evaluate the relationship between morphometric parameters of metaphase II (MII) oocytes and the morphokinetic behaviour of subsequent embryos derived by intra-cytoplasmic sperm injection (ICSI). The association between oocyte morphometry: (whole oocyte), ooplasm, width of zona pellucida (ZP) and perivitelline space (PVS) and first polar body (PB) with embryo morphokinetic variables, including time of second PB extrusion (tPB2), pronuclei appearance (tPN), pronuclei fading (tPNf), formation of two to eight cells (t2 to t8) and irregular cleavage events [uneven at two cells stage, cell fusion (Fu) and trichomonas mitoses (TM)] were assessed. tPB2, t5 and t8 timings were related to the ooplasm diameter (p?=?0.003, r?=??0.12; p?=?0.001, r?=??0.16; p?r?=??0.36, respectively); otherwise, there were no significant relationships apart from an association between the oocyte morphometry and other morphokinetic parameters, irregular cleavage embryos as well as embryo arrest which approached significance (p?>?0.05). Overall, the data showed that morphometric parameters of oocytes did not provide a tool for the prediction of embryo morphokinetic or embryo selection in ICSI cycles. However, ooplasm diameter might be useful as a marker for predicting the timing of embryo cleavage.  相似文献   
7.
目的评价经自然腔道精囊镜技术治疗血精症的临床效果。方法以广东省江门市中心医院2015年3月-2019年8月收治的20例难治性血精症或保守治疗失败的血精症患者为研究对象,随机分成观察组和对照组各10例,观察组使用自然腔道精囊镜技术,对照组使用破窗法精囊镜技术,比较两组患者的治疗效果。结果观察组患者的治疗有效率为90.00%,高于对照组的70.00%,差异有统计学意义(P<0.05)。观察组并发症发生率为20.00%,对照组为10.00%,两组差异无统计学意义(P>0.05)。结论经自然腔道精囊镜技术治疗血精症具有更好的疗效,且并发症发生率与破窗法无明显差异,提示经自然腔道精囊镜技术更加安全有效,值得临床推广应用。  相似文献   
8.
9.
Increasing evidence indicates that extracellular vesicles (EVs) play an important role in cancer cell‐to‐cell communication. The Epstein‐Barr virus (EBV)‐encoded latent membrane protein 1 (LMP1), which is closely associated with nasopharyngeal carcinoma (NPC) pathogenesis, can trigger multiple cell signaling pathways that affect cell progression. Several reports have shown that LMP1 promotes EV secretion, and LMP1 trafficking by EVs can enhances cancer progression and metastasis. However, the molecular mechanism by which LMP1 promotes EV secretion is not well understood. In the present study, we found that LMP1 promotes EV secretion by upregulated syndecan‐2 (SDC2) and synaptotagmin‐like‐4 (SYTL4) through nuclear factor (NF)‐κB signaling in NPC cells. Further study indicated that SDC2 interacted with syntenin, which promoted the formation of the EVs, and SYTL4 is associated with the release of EVs. Moreover, we found that stimulation of EV secretion by LMP1 can enhance the proliferation and invasion ability of recipient NPC cells and tumor growth in vivo. In summary, we found a new mechanism by which LMP1 upregulates SDC2 and SYTL4 through NF‐κB signaling to promote EV secretion, and further enhance cancer progression of NPC.  相似文献   
10.
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