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   36153篇
  免费   1045篇
  国内免费   2898篇
耳鼻咽喉   173篇
儿科学   165篇
妇产科学   130篇
基础医学   1308篇
口腔科学   372篇
临床医学   1464篇
内科学   2450篇
皮肤病学   216篇
神经病学   668篇
特种医学   4801篇
外国民族医学   223篇
外科学   2390篇
综合类   18214篇
现状与发展   23篇
一般理论   1篇
预防医学   1601篇
眼科学   1933篇
药学   1530篇
  17篇
中国医学   1196篇
肿瘤学   1221篇
  2023年   231篇
  2022年   383篇
  2021年   242篇
  2020年   165篇
  2019年   693篇
  2018年   829篇
  2017年   316篇
  2016年   397篇
  2015年   474篇
  2014年   1346篇
  2013年   719篇
  2012年   1333篇
  2011年   1315篇
  2010年   562篇
  2009年   643篇
  2008年   930篇
  2007年   1237篇
  2006年   6261篇
  2005年   6922篇
  2004年   893篇
  2003年   1338篇
  2002年   966篇
  2001年   1303篇
  2000年   855篇
  1999年   545篇
  1998年   340篇
  1997年   264篇
  1996年   180篇
  1995年   428篇
  1994年   193篇
  1993年   297篇
  1992年   265篇
  1991年   334篇
  1990年   300篇
  1989年   556篇
  1988年   525篇
  1987年   572篇
  1986年   425篇
  1985年   551篇
  1984年   520篇
  1983年   444篇
  1982年   341篇
  1981年   313篇
  1980年   203篇
  1963年   113篇
  1959年   160篇
  1958年   235篇
  1957年   224篇
  1956年   128篇
  1955年   166篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
正目的非增强CT常常观察到心肌脂肪,但对其认识不足,本文旨在探究心肌内脂肪与全因死亡率的关系,无论是否有心肌梗死病史。方法本回顾性队列研究收集了不  相似文献   
2.
3.
正摘要虽然乳腺癌的发病率和死亡率随着年龄的增长而增加,但有关老年妇女筛查乳腺X线检查的益处和风险,以及老年妇女二维数字乳腺X线摄影(DM)和数字乳腺断层成  相似文献   
4.
Objective:Pancreatic ductal adenocarcinoma(PDAC)is a deadly malignancy,due in large part to its resistance to conventional therapies,including radiotherapy(RT).Despite RT exerting a modest antitumor response,it has also been shown to promote an immunosuppressive tumor microenvironment.Previous studies demonstrated that focal adhesion kinase inhibitors(FAKi)in clinical development inhibit the infiltration of suppressive myeloid cells and T regulatory(T regs)cells,and subsequently enhance effector T cell infiltration.FAK inhibitors in clinical development have not been investigated in combination with RT in preclinical murine models or clinical studies.Thus,we investigated the impact of FAK inhibition on RT,its potential as an RT sensitizer and immunomodulator in a murine model of PDAC.Methods:We used a syngeneic orthotopic murine model to study the effect of FAKi on hypofractionated RT.Results:In this study we showed that IN10018,a small molecular FAKi,enhanced antitumor response to RT.Antitumor activity of the combination of FAKi and RT is T cell dependent.FAKi in combination with RT enhanced CD8+T cell infiltration significantly in comparison to the radiation or FAKi treatment alone(P<0.05).FAKi in combination with radiation inhibited the infiltration of granulocytes but enhanced the infiltration of macrophages and T regs in comparison with the radiation or FAKi treatment alone(P<0.01).Conclusions:These results support the clinical development of FAKi as a radiosensitizer for PDAC and combining FAKi with RT to prime the tumor microenvironment of PDAC for immunotherapy.  相似文献   
5.
The ocular surface is covered by an epithelium encompassing an area including the cornea,the limbus and the conjunctiva bordered by the upper and lower lids.The healthy state of the ocular surface epithelium depends on a stable and protective preocular tear film when the eye is open.A stable preocular tear film is governed by sound ocular surface defense that involves effective neuroanatomic integration of compositional and hydrodynamic factors by two neural reflexes (1).  相似文献   
6.
Objective:Anoctamin 7(ANO7)is a calcium2+-dependent chloride ion channel protein.Its expression is restricted to prostate epithelial cells.The exact function is unknown.This study aimed to analyze ANO7 expression and its clinical significance in prostate cancer(PCa).Methods:ANO7 expression was assessed by immunohistochemistry in 17,747 clinical PCa specimens.Results:ANO7 was strongly expressed in normal prostate glandular cells but often less abundant in cancer cells.ANO7 staining was interpretable in 13,594 cancer tissues and considered strong in 34.4%,moderate in 48.7%,weak in 9.3%,and negative in 7.6%.Reduced staining was tightly linked to adverse tumor features[high classical and quantitative Gleason grade,lymph node metastasis,advanced tumor stage,high Ki67 labeling index,positive surgical margin,and early biochemical recurrence(P<0.0001 each)].The univariate Cox hazard ratio for prostate-specific antigen(PSA)recurrence after prostatectomy in patients with negative vs.strong ANO7 expression was 2.98(95%confidence interval 2.61–3.38).The prognostic impact was independent of established pre-or postoperatively available parameters(P<0.0001).Analysis of annotated molecular data showed that low ANO7 expression was linked to TMPRSS2:ERG fusions(P<0.0001),elevated androgen receptor expression(P<0.0001),as well as presence of 9 of 11 chromosomal deletions(P<0.05 each).A particularly strong association of low ANO7 expression with phosphatase and tensin homolog(PTEN)deletion may indicate a functional relationship with the PTEN/AKT pathway.Conclusions:These data identify reduced ANO7 protein expression as a strong and independent predictor of poor prognosis in PCa.ANO7 measurement,either alone or in combination,might provide clinically useful prognostic information in PCa.  相似文献   
7.
<正>Glial cells play a key role during nervous system development and actively participate in all the cellular processes involved in maintaining its structural robustness and functional plasticity.In response to neuronal damage,glial cells proliferate,migrate to the injured region and change their morphology,function,and behavior  相似文献   
8.
TWIK-related potassium channels(TREK) belong to a subfamily of the two-pore domain potassium channels family with three members, TREK1, TREK2 and TWIK-related arachidonic acid-activated potassium channels. The two-pore domain potassium channels is the last big family of channels being discovered, therefore it is not surprising that most of the information we know about TREK channels predominantly comes from the study of heterologously expressed channels. Notwithstanding, in this review we pay special attention to the limited amount of information available on native TREK-like channels and real neurons in relation to neuroprotection. Mainly we focus on the role of free fatty acids, lysophospholipids and other neuroprotective agents like riluzole in the modulation of TREK channels, emphasizing on how important this modulation may be for the development of new therapies against neuropathic pain, depression, schizophrenia, epilepsy, ischemia and cardiac complications.  相似文献   
9.
正摘要目的利用多参数MR成像图谱和全肿瘤直方图分析三阴性(TN)乳腺癌与其他分子亚型鉴别的影像学生物标志。方法本回顾性研究包括134例浸润性导管癌病人。从  相似文献   
10.
正摘要目的使用双能量CT计算肺灌注血容量(PBV)诊断肺血栓栓塞已被广泛接受。本研究评价慢性血栓栓塞性肺高压(CTEPH)病人在球囊肺血管成形术(BPA)前、后的肺  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