全文获取类型
收费全文 | 8933篇 |
免费 | 522篇 |
国内免费 | 291篇 |
专业分类
耳鼻咽喉 | 129篇 |
儿科学 | 117篇 |
妇产科学 | 66篇 |
基础医学 | 1123篇 |
口腔科学 | 779篇 |
临床医学 | 862篇 |
内科学 | 811篇 |
皮肤病学 | 169篇 |
神经病学 | 519篇 |
特种医学 | 525篇 |
外科学 | 643篇 |
综合类 | 1435篇 |
预防医学 | 371篇 |
眼科学 | 323篇 |
药学 | 1073篇 |
2篇 | |
中国医学 | 375篇 |
肿瘤学 | 424篇 |
出版年
2024年 | 9篇 |
2023年 | 89篇 |
2022年 | 176篇 |
2021年 | 309篇 |
2020年 | 257篇 |
2019年 | 198篇 |
2018年 | 220篇 |
2017年 | 245篇 |
2016年 | 251篇 |
2015年 | 265篇 |
2014年 | 481篇 |
2013年 | 551篇 |
2012年 | 422篇 |
2011年 | 529篇 |
2010年 | 396篇 |
2009年 | 403篇 |
2008年 | 429篇 |
2007年 | 418篇 |
2006年 | 361篇 |
2005年 | 335篇 |
2004年 | 344篇 |
2003年 | 291篇 |
2002年 | 283篇 |
2001年 | 233篇 |
2000年 | 219篇 |
1999年 | 190篇 |
1998年 | 176篇 |
1997年 | 139篇 |
1996年 | 111篇 |
1995年 | 143篇 |
1994年 | 114篇 |
1993年 | 109篇 |
1992年 | 101篇 |
1991年 | 97篇 |
1990年 | 88篇 |
1989年 | 65篇 |
1988年 | 69篇 |
1987年 | 62篇 |
1986年 | 62篇 |
1985年 | 71篇 |
1984年 | 83篇 |
1983年 | 48篇 |
1982年 | 62篇 |
1981年 | 40篇 |
1980年 | 45篇 |
1979年 | 37篇 |
1978年 | 35篇 |
1977年 | 24篇 |
1976年 | 21篇 |
1975年 | 13篇 |
排序方式: 共有9746条查询结果,搜索用时 46 毫秒
1.
2.
Mohid S Khan Thomas Walter Amy Buchanan-Hughes Emma Worthington Lucie Keeber Marion Feuilly Enrique Grande 《World journal of gastroenterology : WJG》2020,26(30):4537-4556
BACKGROUND Approximately 20% of patients with neuroendocrine tumours(NETs) develop carcinoid syndrome(CS),characterised by flushing and diarrhoea.Somatostatin analogues or telotristat can be used to control symptoms of CS through inhibition of serotonin secretion.Although CS is often the cause of diarrhoea among patients with gastroenteropancreatic NETs(GEP-NETs),other causes to consider include pancreatic enzyme insufficiency(PEI),bile acid malabsorption and small intestinal bacterial overgrowth.If other causes of diarrhoea unrelated to serotonin secretion are mistaken for CS diarrhoea,these treatments may be ineffective against the diarrhoea,risking detrimental effects to patient quality of life.AIM To identify and synthesise qualitative and quantitative evidence relating to the differential diagnosis of diarrhoea in patients with GEP-NETs.METHODS Electronic databases(MEDLINE,Embase and the Cochrane Library) were searched from inception to September 12,2018 using terms for NETs and diarrhoea.Congresses,systematic literature review bibliographies and included articles were also hand-searched.Any study designs and publication types were eligible for inclusion if relevant data on a cause(s) of diarrhoea in patients with GEP-NETs were reported.Studies were screened by two independent reviewers at abstract and full-text stages.Framework synthesis was adapted to synthesise quantitative and qualitative data.The definition of qualitative data was expanded to include all textual data in any section of relevant publications.RESULTS Forty-seven publications(44 studies) were included,comprising a variety of publication types,including observational studies,reviews,guidelines,case reports,interventional studies,and opinion pieces.Most reported on PEI on/after treatment with somatostatin analogs;9.5%-84% of patients with GEP-NETs had experienced steatorrhoea or confirmed PEI.Where reported,14.3%–50.7% of patients received pancreatic enzyme replacement therapy.Other causes of diarrhoea reported in patients with GEP-NETs included bile acid malabsorption(80%),small intestinal bacterial overgrowth(23.6%-62%),colitis(20%) and infection(7.1%).Diagnostic approaches included faecal elastase,breath tests,tauroselcholic(selenium-75) acid(Se HCAT) scan and stool culture,although evidence on the effectiveness or diagnostic accuracy of these approaches was limited.Assessment of patient history or diarrhoea characteristics was also reported as initial approaches for investigation.From the identified evidence,if diarrhoea is assumed to be CS diarrhoea,consequences include uncontrolled diarrhoea,malnutrition,and perceived ineffectiveness of CS treatment.Approaches for facilitating differential diagnosis of diarrhoea include improving patient and clinician awareness of non-CS causes and involvement of a multidisciplinary clinical team,including gastroenterologists.CONCLUSION Diarrhoea in GEP-NETs can be multifactorial with misdiagnosis leading to delayed patient recovery and inefficient resource use.This systematic literature review highlights gaps for further research on prevalence of non-CS diarrhoea and suitability of diagnostic approaches,to determine an effective algorithm for differential diagnosis of GEP-NET diarrhoea. 相似文献
3.
目的:了解建德市基层医院儿科门诊进行X线扫描治疗中,家属对X射线检查的知情同意与接受现状。方法:随机抽取建德市属3家公立综合性医院共60位接受X线扫描的儿童患者家属为调查对象,发放自制调查问卷并统计分析。结果:55位(91.67%)患者表示治疗前主治医生只告知了X射线是诊断性检查,没有具体告知X射线的危害性;18位(30%)的患者家属不清楚辐射会对人体有损害,42位(70%)不清楚或不注意辐射警示标志,更不会主动要求防护措施,学历水平较高者及有从事医务工作背景者接受X射线检查的为12人(20%),明显低于学历水平低者或没有从事医务工作背景者的46人(76.67%),不知可否接受的有2人(3.33%)(P<0.001)。结论:基层医院儿科诊断性X射线扫描前的知情同意告知仍需加强,儿科放射检查偏多,应避免并加强宣传和教育。 相似文献
4.
《Journal of prosthodontic research》2020,64(2):167-174
PurposeFew investigations have examined the production of single restorations using intraoral scanners (IOS). Data on full-arch scans are rare, and data regarding torsion within the entire arch are very sparsely reported. Therefore, the aim of this study was to examine the deviations of torsion and linear distances in full-arch scans of three IOS based on different scanning principles.MethodsA cobalt-chrome-molybdenum alloy master model (CCMM) with four hemispheres was fabricated by laser sintering. The CCMM was digitized using a laboratory scanner (ATOS-Core/GOM) and scanned with three IOS (Omnicam/Sirona(OC); True Definition/3M(TD); TriosII/Cara-Version/Kulzer(TR)). All scan data were exported in a standard STL-file format and were analyzed with GOM Inspect software (V7.5/GOM). Torsion between the right and left side of the arch and linear accuracy (trueness and precision) were evaluated. After normality was confirmed, all data were subjected to parametric statistical analyses.ResultsThe torsion ranged from 0.07 ± 0.03°(OC) to 0.29 ± 0.14°(TD). Pairwise comparisons showed significant differences between the OC and TD scanners and between the TR and TD scanners. The linear distances ranged from 6 ± 5 μm(OC) to 298 ± 317 μm(TD). Significant differences were observed among all investigated IOS (p = 0.05).ConclusionsAlthough the highest torsion was observed for the TD scanner, it is still not clear whether the differences between the IOS are related to the scanning principle or to the scanning algorithm. Due to the high clinical relevance of full-arch restorations, future studies should consider torsion. Regarding linear accuracy, no general difference related to the scanning principles of the IOSs was observed. 相似文献
5.
目的 研究凉血通瘀方对高血压大鼠急性脑出血模型脑组织miRNA表达的影响,对差异表达的miRNA靶基因进行分析,探索凉血通瘀方可能的药效机制。方法 将自发性高血压大鼠随机分成对照组(B)和实验组(C)。适应性饲养一周后,C组灌胃凉血通瘀方,B组灌胃等体积生理盐水,连续5天,每天1次。构建脑出血模型后收集脑组织,借助全转录组测序技术获得miRNA表达量,与miRBase数据库比对获取已知miRNA,使用miRDeep2预测新miRNA。差异分析软件为DESeq2,筛选阈值为|log2FC| ≥1 并且P <0.05。对显著差异表达的miRNA进行靶基因预测,对靶基因进行GO功能、KEGG通路富集和PPI网络分析。结果 实验组和对照组对比,共发现21个显著差异表达的miRNA,上调有9个,下调有12个,共预测得到1243个有统计学意义的靶基因。GO富集分析发现,生物过程中突触囊泡分泌的调节、神经递质分泌的调节和神经递质运输的调节占前三位,神经元投射终点、全膜、质膜区域和细胞投射则是主要的细胞成分。分子功能分别为小GTPase绑定、底物特异性跨膜转运蛋白活性和离子跨膜转运体活性。通路分析结果显示,靶基因在癌证通路、pI3K-Akt信号通路、人类乳头瘤病毒感染、神经活性配体-受体相互作用和MAPK通路等分布广泛。采用STRING网站和Cytoscape软件,根据MCC算法筛选出ADRA2C、CASR、CCL28、CCR1、DRD2、GNAT3、GRM2、DYNC1LI1、GABBR1、GNAI1等核心靶基因。结论 凉血通瘀方对脑出血急性期鼠脑组织内miRNA的表达有重要影响;显著差异表达miRNAs可能通过靶向核心基因调控凉血通瘀方干预急性脑出血的病理过程及预后。 相似文献
6.
7.
8.
目的 本研究使用激光扫描检眼镜(SLO)评价双侧中央暗点患者使用棱镜后的眼球运动反应.方法 本预试验共招募6例有双侧中央暗点的年龄相关性黄斑变性(AMD)患者以及6例正常视力的志愿者.首先用Nidek MP-1微视野仪确认患者的中央暗点和优选视网膜注视点(PRL),然后用Rodenstock SLO,在将视标投射在优选视网膜注视点时拍下实时视网膜像,接着在受检者眼前加入6~8 PD的棱镜,要求受检者保持注视视标,这时通过视网膜标记来测量视网膜像的移位量,以及随后发生的优选视网膜注视点的再次注视.过程中平均移位量和再次注视时间通过图像软件(ImageJ software)来计算.结果 实验组再次注视时的移位量在3个像素点或11.66个弧分之内(x轴:2.90±3.92,y轴:2.53±4.18).对照组再次注视时的移位会准确些(x轴:0.33±1.15,y轴:0.89±2.50),但与实验组差异无统计学意义(tx=1.32,Px>0.05;ty=0.80,Py>0.05).对照组再次注视时间(0.98±0.19)s较实验组(2.83±1.63)s要短,差距有统计学意义(t=5.03,P<0.01).其中有1例实验组受检者没有发生再次注视,其结果被排除并单独分析.结论 研究发现,双眼中央暗点患者对棱镜物像转移后的再注视反应与正常人接近,但实验组再注视明显较对照组慢,并有1例受检者没有发生再注视.该数据说明双侧中央暗点患者无论眼前有没有棱镜,都会利用相同的视网膜位置视物,因此,通过棱镜物像再定位的意义不大. 相似文献
9.
Ferdynand Hebal Elissa Port Catherine J. Hunter Bryan Malas Jared Green Marleta Reynolds 《Journal of pediatric surgery》2019,54(4):656-662
Background/purpose
Computed tomography (CT) derived Haller Index (HI) remains the standard for quantifying severity in patient with pectus excavatum (PE). Optical scanning described in literature reports optimistic results and new indices that correlate with HI. This study assessed the feasibility of a handheld White Light Scanner (WLS) to obtain 3D measurements and indices of PE deformity.Methods
From April 2015–April 2017, WLS scanning was conducted by orthotists during clinical visits. Included were children with PE up to 18?years. Analysis assessed correlation of a WLS-derived severity index, Hebal-Malas Index (HMI), with physician measured PE Depth (PED), and CT-derived HI.Results
Of 195 participants, 185(94%) patients with PE were scanned and 127(69%) had complete WLS data. For 88 patients undergoing monitoring, HMI correlated with PED (r?=?0.42, p?=?0.004). For 39 patients with pre-operative CT, HMI demonstrated strong correlation with HI (r?=?0.87, p < 0.0001).Conclusions
WLS demonstrated high feasibility of scanning PE. WLS-derived HMI best correlates with HI for patients with severe pectus deformity. Our current data is suggestive that WLS is best applied for severe deformities and yet to be established for milder deformities. Future yearly WLS will provide data on deformity progression and surgical therapy.Level of Evidence
IV.Type of Study
Diagnostic Study. 相似文献10.
目的探讨腹腔积液中CA153联合CA199对良恶性腹腔积液的鉴别诊断价值。方法选择98例腹腔积液患者,经手术病理诊断为恶性腹腔积液者为观察组(48例),良性腹腔积液者为对照组(50例)。检测并比较2组患者腹腔积液中的CA153、CA199水平及CA153、CA199的阳性结果,分析CA153及CA155单用及联合应用对恶性腹腔积液的诊断效能。结果观察组腹腔积液中的CA153及CA199水平均明显高于对照组,P <0. 05。观察组CA153及CA199阳性率明显高于对照组,P <0. 05。CA153、CA199对恶性腹腔积液诊断的敏感性、特异性及准确性对比,差异无统计学意义(P> 0. 05);CA153+CA199的敏感性、特异性及准确性明显高于单项CA153及CA199(P <0. 05)。结论 CA153与CA199单项检测对恶性腹腔积液的诊断价值有限,CA153+CA199对恶性腹腔积液的诊断价值较高,值得临床推广应用。 相似文献