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   42683篇
  免费   1399篇
  国内免费   3091篇
耳鼻咽喉   183篇
儿科学   254篇
妇产科学   144篇
基础医学   1508篇
口腔科学   483篇
临床医学   2107篇
内科学   3149篇
皮肤病学   275篇
神经病学   815篇
特种医学   5037篇
外国民族医学   228篇
外科学   3031篇
综合类   20387篇
现状与发展   23篇
一般理论   1篇
预防医学   2203篇
眼科学   1964篇
药学   2137篇
  39篇
中国医学   1762篇
肿瘤学   1443篇
  2024年   165篇
  2023年   417篇
  2022年   563篇
  2021年   387篇
  2020年   368篇
  2019年   916篇
  2018年   1128篇
  2017年   466篇
  2016年   565篇
  2015年   654篇
  2014年   1703篇
  2013年   1082篇
  2012年   1798篇
  2011年   1826篇
  2010年   956篇
  2009年   990篇
  2008年   1249篇
  2007年   1626篇
  2006年   6546篇
  2005年   7211篇
  2004年   1147篇
  2003年   1574篇
  2002年   1113篇
  2001年   1445篇
  2000年   988篇
  1999年   652篇
  1998年   401篇
  1997年   333篇
  1996年   235篇
  1995年   485篇
  1994年   238篇
  1993年   338篇
  1992年   299篇
  1991年   350篇
  1990年   327篇
  1989年   570篇
  1988年   545篇
  1987年   603篇
  1986年   442篇
  1985年   568篇
  1984年   521篇
  1983年   443篇
  1982年   338篇
  1981年   313篇
  1980年   212篇
  1959年   158篇
  1958年   235篇
  1957年   224篇
  1956年   128篇
  1955年   164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.
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   
3.
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   
4.
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   
5.
目的 检测蒜氨酸最低抑菌浓度(MIC)与最低杀菌浓度(MBC),探讨蒜氨酸体内外抗菌机制。方法 体外微量稀释法检测蒜氨酸MIC和MBC,荧光显微镜观察菌体表面蒜氨酸,探讨蒜氨酸抗菌机制。体内蒜氨酸和青霉素分别治疗金葡菌感染家兔脓肿,检测脓汁标本中细菌存活情况,探讨体内蒜氨酸抗菌作用。结果 蒜氨酸对大肠杆菌、伤寒杆菌、金黄色葡萄球菌、白色葡萄球菌的MIC分别为3.047 μg·mL-1、6.094 μg·mL-1、0.386 μg·mL-1、0.386 μg·mL-1,蒜氨酸体外无杀菌活性。浓汁标本:死菌率蒜氨酸治疗组显著高于阴性对照组(P < 0.01),与青霉素治疗组无明显差异(P > 0.05);活菌率蒜氨酸治疗组显著低于阴性对照组(P < 0.01),与青霉素治疗组无明显差异(P > 0.05)。结论 蒜氨酸与菌体蛋白、细菌酶蛋白结合阻断细菌与环境物质交换,抑制细菌生命活动,具有较强的抑菌作用,无杀菌活性;蒜氨酸体内代谢成大蒜素,具有较强杀菌作用。  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.
目的观察25-羟维生素D3(Vit D3)对2型糖尿病(T2DM)患者早期肾损害的临床疗效。方法纳入T2DM早期肾损伤患者80例,采用随机数字表法等分为治疗组与对照组,对照组继续原有降糖方案,治疗组在既往用药基础上,肌肉注射Vit D3注射液,疗程均为10个月,治疗结束后进行疗效评价。结果 1与治疗前相比,治疗组糖化血红蛋白(HbA1c)、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)水平上调,微量白蛋白(MA)、β2-微球蛋白(β2-M)及肾脏损伤分子-1(KIM-1)水平下调,治疗组低于对照组差异有统计学意义(P<0.05)。2与治疗前相比,治疗组治疗后Vit D3水平上调,治疗组高于对照组差异有统计学意义(P<0.01)。3T2DM患者Vit D3水平与MA(r=-0.432),β2-M(r=-0.615),及KIM-1(r=-0.763)水平均呈负相关(P<0.05)。结论 Vit D3可有效减轻T2DM患者的早期肾损害,对肾脏具有保护作用。  相似文献   
8.
9.
<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   
10.
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   
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