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   13316篇
  免费   1208篇
  国内免费   1051篇
耳鼻咽喉   120篇
儿科学   151篇
妇产科学   111篇
基础医学   1697篇
口腔科学   284篇
临床医学   1823篇
内科学   2045篇
皮肤病学   81篇
神经病学   725篇
特种医学   470篇
外国民族医学   10篇
外科学   1250篇
综合类   2356篇
现状与发展   2篇
一般理论   1篇
预防医学   764篇
眼科学   369篇
药学   1449篇
  13篇
中国医学   720篇
肿瘤学   1134篇
  2024年   55篇
  2023年   275篇
  2022年   618篇
  2021年   721篇
  2020年   489篇
  2019年   456篇
  2018年   477篇
  2017年   465篇
  2016年   408篇
  2015年   610篇
  2014年   763篇
  2013年   661篇
  2012年   964篇
  2011年   1162篇
  2010年   627篇
  2009年   526篇
  2008年   688篇
  2007年   645篇
  2006年   695篇
  2005年   707篇
  2004年   465篇
  2003年   381篇
  2002年   354篇
  2001年   266篇
  2000年   279篇
  1999年   364篇
  1998年   240篇
  1997年   232篇
  1996年   146篇
  1995年   153篇
  1994年   110篇
  1993年   83篇
  1992年   83篇
  1991年   79篇
  1990年   77篇
  1989年   53篇
  1988年   41篇
  1987年   27篇
  1986年   35篇
  1985年   38篇
  1984年   26篇
  1983年   11篇
  1982年   5篇
  1981年   5篇
  1980年   2篇
  1979年   7篇
  1976年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
目的观察乐舒痰对小儿急性下呼吸道感染的祛痰效果以及量化咳嗽、峰流值(PEF)作为疗效观察指标的可行性.方法将106例急性下呼吸道感染的患儿随机分为治疗组55例和对照组51例,并设计了量化咳嗽和PEF等观察指标.结果两组患儿的综合疗效无明显差异(P>0.05),但乐舒痰组患儿的咳嗽、肺部干性罗音及PEF恢复正常的时间明显短于对照组((P<0.05).同时还显示,量化咳嗽和PEF能更早地反映上述统计学上的差异.结论①乐舒痰是一种安全有效的祛痰剂;②量化咳嗽和PEF是开展祛痰药物对小儿祛痰作用研究的两个客观而实用的指标.  相似文献   
82.
目的 观察新生儿口腔微生物的早期定植情况 ,确定健康新生儿口腔正常微生物群的组成以及新生儿口腔中的优势细菌。方法 对 2 2名健康新生儿口腔进行棉拭子取样 ,在需氧、兼性厌氧、厌氧条件下培养 ,培养均采用成品培养基和培养盒 ,培养结果作微生物的形态学及生化鉴定。结果  90 .9%的刚出生健康新生儿口腔中无菌 ;4 5 .5 %的新生儿出生第 2天即可检出 Streptococcus salivarius(S.salivarius) ,2 7.3%可检出 Streptococ-cus mitis(S.mitis) ,到出生后第 2 8天这两种菌的检出率分别达 86 .4 %和 81.8% ;Candida albicans(C.albicans)在1月龄新生儿口腔中检出率为 2 2 .7% ;母乳喂养与人工喂养的新生儿口腔正常微生物群之间无明显差异 (P>0 .0 5 )。结论 在早期定植于健康新生儿口腔生态区的正常微生物中 ,S.salivarius和 S.mitis为其优势细菌 ,C.albi-cans为优势真菌。不同喂养方式对新生儿口腔优势菌群的组成和数量无明显影响。  相似文献   
83.
目的 调查住院癌症患者口腔衰弱现状,分析其影响因素,为针对性干预提供参考。方法 采用便利抽样法抽取207例住院癌症患者为调查对象,采用一般资料问卷、口腔衰弱指数-8、口腔健康评估量表、营养风险筛查量表2002、衰弱量表、领悟社会支持量表进行调查。结果 住院癌症患者口腔衰弱发生率为64.3%,年龄、吸烟史、化疗史、口干、义齿、口腔健康不良、身体衰弱是住院癌症患者口腔衰弱的影响因素(均P<0.05)。结论 住院癌症患者口腔衰弱发生率较高,医护人员需根据其影响因素采取预防管理措施,控制口腔衰弱的发生和发展。  相似文献   
84.
Obesity is a highly prevalent disease that can induce metabolic syndrome and is associated with a greater risk of muscular atrophy. Mitochondria play central roles in regulating the physiological metabolism of skeletal muscle; however, whether a decreased mitochondrial function is associated with impaired muscle function is unclear. In this study, we evaluated the effects of a high-fat diet on muscle mitochondrial function in a zebrafish model of sarcopenic obesity (SOB). In SOB zebrafish, a significant decrease in exercise capacity and skeletal muscle fiber cross-sectional area was detected, accompanied by high expression of the atrophy-related markers Atrogin-1 and muscle RING-finger protein-1. Zebrafish with SOB exhibited inhibition of mitochondrial biogenesis and fatty acid oxidation as well as disruption of mitochondrial fusion and fission in atrophic muscle. Thus, our findings showed that muscle atrophy was associated with SOB-induced mitochondrial dysfunction. Overall, these results showed that the SOB zebrafish model established in this study may provide new insights into the development of therapeutic strategies to manage mitochondria-related muscular atrophy.  相似文献   
85.
目的:探索Ezscan在无症状人群中筛查糖代谢异常的能力。方法选取2013年8月至2014年8月进行健康体检的重庆市常驻居民1732例,进行问卷调查、体格检查、空腹血糖(FPG)、葡萄糖耐量试验(OGTT)2h血糖、糖化血红蛋白(HbA1c)、血脂和Ezscan检测。结果Ezscan高评分人群糖代谢异常患病率高于低评分人群。Ezscan筛查糖代谢异常的受试者工作特征曲线下面积(AUC)为0.616,最佳切点值为24%,灵敏度为67.0%;FPG筛查糖代谢异常最佳切点值为5.5mmol/L,灵敏度和特异度分别为70.5%和61.7%,AUC为0.824;FPG为6.1mmol/L时,筛查糖代谢异常的灵敏度为47.2%。结论重庆地区Ezscan筛查糖代谢异常灵敏度高于经典方法FPG(切点值为6.1mmol/L)检测,在无症状人群中,Ezscan可作为一种有效的糖代谢异常早期筛查技术。  相似文献   
86.
BackgroundIt is considered that circRNA can participate in regulating the occurrence and effects of ventricular arrhythmia (VA) through competing endogenous RNA (ceRNA) mechanism, regulating pre-mRNA and regulating parental gene expression. Therefore, we used animal modeling and high-throughput differential screening to screen out circRNA related to VA and study its possible mechanism of action on VA.MethodsThe rat model of myocardial ischemia VA was established. High-throughput screening of the differentiated circRNA was conducted and verified by real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot. Lv-circRNA01724 lentivirus was constructed using molecular biology. Primary isolation of the rat cardiomyocytes, hypoxia modeling, Lv-circRNA01724 transfection, mode of action verification, and dual luciferase detection of circRNA01724 and miR-323-5p was performed.ResultsThrough qRT-PCR verification of circRNA01724, circRNA02230, circRNA02088, miR-323-5p, miR-330-5p, and miR-324-3p expressions, circRNA01724 was selected as the research object. Detection by Western blot showed significantly lower Cx43, ZO-1, and α-catenin expressions in rat myocardial tissue in the model group compared with the control group at 1, 7, 14, and 28 days old. On identification of the isolated primary rat cardiomyocytes by immunofluorescence, the α-SMA characteristic protein expression indicated that the isolation was successful. Verification of rat cardiomyocytes transfected with Lv-circRNA01724 suggested overexpression in cells. The miR-323-5p was also highly expressed in the rat cardiomyocyte hypoxia model following Lv-circRNA01724 transfection. Detection by flow cytometry showed that modeling of the transfected Lv-circRNA01724 had a significant increased apoptotic rate. Detection by Western blot showed that modeling of the transfected Lv-circRNA01724 cells had significantly decreased Cx43, ZO-1, and α-catenin compared with the model group.ConclusionsHigh-throughput screening of circRNA01724 can promote the apoptosis of hypoxic cardiomyocytes, which is related to the rat model of myocardial ischemia VA and may be a potential target for the treatment of VA.  相似文献   
87.
目的探讨渐量修正平均法检测健康人微伏级T波电交替(microvolt T wave alternans,MTWA)的正常范围。方法平板运动提升心率,渐量修正平均法检测120例健康志愿者各胸前导联T波交替电压(alternans voltage,Valt),分析其大小分布范围及与性别、年龄的关系。结果(1)各胸前导联T波交替电压数据均呈偏态分布;胸前导联Valt大小与年龄无关;V4、V5导联Valt男女性别间差异有统计学意义,女性高于男性。(2)各胸前导联T波交替电压有较大差别,第75百分位数分别为V1导联8.0μV;V2导联5.0μV;V3导联2.0μV;V4导联男性2.0μV,女性6.0μV;V5导联男性4.5μV,女性6.5μV;V6导联7.0μV;胸前导联T波交替电压最大值(Vmax)第75百分位数11.0μV。结论:渐量修正平均法检测健康人微伏级T波电交替不同胸前导联之间有较大差别;确定正常标准需要因导联而异。  相似文献   
88.
Several inflammatory cytokines that promote inflammation and pathogenesis in asthma signal through the Janus kinase 1 (JAK1) pathway. This phase I, randomized, placebo‐controlled trial assessed the pharmacokinetics and safety of single and multiple ascending doses up to 15 mg twice daily for 14 days of a JAK1 inhibitor, GDC‐0214, in healthy volunteers (HVs; n = 66). Doses were administered with a dry powder, capsule‐based inhaler. An accompanying open‐label gamma scintigraphy study in HVs examined the lung deposition of a single dose of inhaled Technetium‐99m (99mTc)‐radiolabeled GDC‐0214. GDC‐0214 plasma concentrations were linear and approximately dose‐proportional after both single and multiple doses. Peak plasma concentrations occurred at 15–30 min after dosing. The mean apparent elimination half‐life ranged from 32 to 56 h across all single and multiple dose cohorts. After single and multiple doses, all adverse events were mild or moderate, and none led to treatment withdrawal. There was no clear evidence of systemic toxicity due to JAK1 inhibition, and systemic exposure was low, with plasma concentrations at least 15‐fold less than the plasma protein binding‐corrected IC50 of JAK1 at the highest dose. Scintigraphy showed that approximately 50% of the emitted dose of radiolabeled GDC‐0214 was deposited in the lungs and was distributed well to the peripheral airways. 99mTc‐radiolabeled GDC‐0214 (1 mg) exhibited a mean plasma Cmax similar to that observed in phase I at the same dose level. Overall, inhaled GDC‐0214 exhibited pharmacokinetic properties favorable for inhaled administration.

Study Highlights
  • WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?
Many factors drive asthma pathogenesis, including several cytokines that signal through the Janus kinase 1 (JAK1) pathway. Inhibition of JAK1 is a possible target for asthma treatments, but previous studies show oral JAK1 inhibitors lead to increased risk of severe infections, malignancy and cardiovascular events.
  • WHAT QUESTION DID THIS STUDY ADDRESS?
This study investigated the safety, pharmacokinetics, and lung deposition of GDC‐0214, an inhaled JAK1 inhibitor designed to target the lungs.
  • WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?
Inhaled delivery of a JAK inhibitor for 14 days exhibited low systemic exposure, leading to few adverse events and limited systemic toxicity, while demonstrating high deposition in the lungs.
  • HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?
Local pulmonary application of JAK inhibitors may be an effective treatment for asthma with limited systemic risks.  相似文献   
89.
目的:探讨DNA 聚合酶 ι(DNA polymerase ι,Pol ι)表达水平对行食管癌术后辅助放疗患者的生存影响。方法:采用免疫组化方法检测97例行术后辅助放疗的食管癌患者组织中Pol ι的表达情况,分析Pol ι表达水平对这些患者生存的影响。结果:20例食管癌患者组织中Pol ι呈低表达,77例食管癌患者组织中Pol ι呈高表达;生存曲线显示Pol ι表达水平与行术后辅助放疗的食管癌患者生存呈负相关;COX回归分析显示Pol ι表达水平是影响食管癌根治术后辅助放疗患者生存的独立预后因素。结论:Pol ι可能是判断行食管癌术后辅助放疗患者预后的潜在分子标志物。  相似文献   
90.
维拉帕米脉冲控释片的设计和制备   总被引:9,自引:1,他引:9  
目的:针对高血压、心绞痛常在凌晨发作的特点,研制夜间服药、凌晨释放的维拉帕米(VR)脉冲控释片。方法:全面考察影响药物释放滞后时间的因素。选用3种强崩解剂的不同用量,考察片芯崩解剂对时滞的影响。通过均匀设计实验考察外层包衣的组成和片剂的硬度,多元回归筛选最优处方,并考察不同溶出条件对控释效果的影响。结果:片芯所用的3种崩解剂以羧甲基淀粉钠的崩解性能较好,用量设计在25%左右。外层包衣处方中PEG 6000增加,氢化蓖麻油(HCO)、乙烯-醋酸乙烯共聚物(EVA)用量减少,硬度减小,释放滞后时间减少。由此确定释放滞后时间为3和5h的两个基本处方。结论:VR压制包衣片在体外溶出实验中能实现脉冲释药,并能通过调节辅料用量实现不同控释效果。  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