全文获取类型
收费全文 | 1375585篇 |
免费 | 99443篇 |
国内免费 | 6049篇 |
专业分类
耳鼻咽喉 | 20198篇 |
儿科学 | 40696篇 |
妇产科学 | 39019篇 |
基础医学 | 191195篇 |
口腔科学 | 40523篇 |
临床医学 | 116991篇 |
内科学 | 266975篇 |
皮肤病学 | 30762篇 |
神经病学 | 108424篇 |
特种医学 | 55974篇 |
外国民族医学 | 454篇 |
外科学 | 212691篇 |
综合类 | 39587篇 |
一般理论 | 442篇 |
预防医学 | 94400篇 |
眼科学 | 32532篇 |
药学 | 105186篇 |
35篇 | |
中国医学 | 5722篇 |
肿瘤学 | 79271篇 |
出版年
2018年 | 12960篇 |
2016年 | 11969篇 |
2015年 | 14188篇 |
2014年 | 19638篇 |
2013年 | 28142篇 |
2012年 | 37244篇 |
2011年 | 39361篇 |
2010年 | 23991篇 |
2009年 | 22712篇 |
2008年 | 36575篇 |
2007年 | 39666篇 |
2006年 | 39933篇 |
2005年 | 38656篇 |
2004年 | 36996篇 |
2003年 | 36058篇 |
2002年 | 35225篇 |
2001年 | 64742篇 |
2000年 | 66091篇 |
1999年 | 55897篇 |
1998年 | 14361篇 |
1997年 | 13124篇 |
1996年 | 12449篇 |
1995年 | 12546篇 |
1994年 | 11691篇 |
1992年 | 42937篇 |
1991年 | 41444篇 |
1990年 | 40664篇 |
1989年 | 39655篇 |
1988年 | 37015篇 |
1987年 | 36490篇 |
1986年 | 34957篇 |
1985年 | 33137篇 |
1984年 | 24810篇 |
1983年 | 20994篇 |
1982年 | 12625篇 |
1981年 | 11515篇 |
1979年 | 23873篇 |
1978年 | 17015篇 |
1977年 | 14759篇 |
1976年 | 13307篇 |
1975年 | 15185篇 |
1974年 | 18024篇 |
1973年 | 17527篇 |
1972年 | 16777篇 |
1971年 | 15676篇 |
1970年 | 14860篇 |
1969年 | 14315篇 |
1968年 | 13430篇 |
1967年 | 11984篇 |
1966年 | 11240篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Xiaohui Lin Sebastiaan W F Meenderink Glenna Stomackin Timothy T Jung Glen K Martin Wei Dong 《Journal of the Association for Research in Otolaryngology》2021,22(3):261
Tympanic membranes (TM) that have healed spontaneously after perforation present abnormalities in their structural and mechanical properties; i.e., they are thickened and abnormally dense. These changes result in a deterioration of middle ear (ME) sound transmission, which is clinically presented as a conductive hearing loss (CHL). To fully understand the ME sound transmission under TM pathological conditions, we created a gerbil model with a controlled 50% pars tensa perforation, which was left to heal spontaneously for up to 4 weeks (TM perforations had fully sealed after 2 weeks). After the recovery period, the ME sound transmission, both in the forward and reverse directions, was directly measured with two-tone stimulation. Measurements were performed at the input, the ossicular chain, and output of the ME system, i.e., at the TM, umbo, and scala vestibuli (SV) next to the stapes. We found that variations in ME transmission in forward and reverse directions were not symmetric. In the forward direction, the ME pressure gain decreased in a frequency-dependent manner, with smaller loss (within 10 dB) at low frequencies and more dramatic loss at high frequency regions. The loss pattern was mainly from the less efficient acoustical to mechanical coupling between the TM and umbo, with little changes along the ossicular chain. In the reverse direction, the variations in these ears are relatively smaller. Our results provide detailed functional observations that explain CHL seen in clinical patients with abnormal TM, e.g., caused by otitis media, that have healed spontaneously after perforation or post-tympanoplasty, especially at high frequencies. In addition, our data demonstrate that changes in distortion product otoacoustic emissions (DPOAEs) result from altered ME transmission in both the forward and reverse direction by a reduction of the effective stimulus levels and less efficient transfer of DPs from the ME into the ear canal. This confirms that DPOAEs can be used to assess both the health of the cochlea and the middle ear. 相似文献
2.
Marike Gabrielson Mattias Hammarström Magnus Bäcklund Jenny Bergqvist Kristina Lång Ann H Rosendahl Signe Borgquist Roxanna Hellgren Kamila Czene Per Hall 《International journal of cancer. Journal international du cancer》2023,152(11):2362-2372
Tamoxifen prevents recurrence of breast cancer and is suggested for preventive risk-reducing therapy. Tamoxifen reduces mammographic density, a proxy for therapy response, but little is known about its effects in remodelling normal breast tissue. Our study, a substudy within the double-blinded dose-determination trial KARISMA, investigated tamoxifen-specific changes in breast tissue composition and histological markers in healthy women. We included 83 healthy women randomised to 6 months daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. The groups were combined to “no dose” (0-1 mg), “low-dose” (2.5-5 mg) or “high-dose” (10-20 mg) of tamoxifen. Ultrasound-guided biopsies were collected before and after tamoxifen exposure. In each biopsy, epithelial, stromal and adipose tissues was quantified, and expression of epithelial and stromal Ki67, oestrogen receptor (ER) and progesterone receptor (PR) analysed. Mammographic density using STRATUS was measured at baseline and end-of-tamoxifen-exposure. We found that different doses of tamoxifen reduced mammographic density and glandular-epithelial area in premenopausal women and associated with reduced epithelium and increased adipose tissue. High-dose tamoxifen also decreased epithelial ER and PR expressions in premenopausal women. Premenopausal women with the greatest reduction in proliferation also had the greatest epithelial reduction. In postmenopausal women, high-dose tamoxifen decreased the epithelial area with no measurable density decrease. Tamoxifen at both low and high doses influences breast tissue composition and expression of histological markers in the normal breast. Our findings connect epithelial proliferation with tissue remodelling in premenopausal women and provide novel insights to understanding biological mechanisms of primary prevention with tamoxifen. 相似文献
3.
Kara S. Tanaka MD Veronica R. Andaya BA Steven W. Thorpe MD Kenneth R. Gundle MD James B. Hayden MD Yee-Cheen Duong MD Raffi S. Avedian MD David G. Mohler MD Lee J. Morse MD Melissa N. Zimel MD Richard J. O'Donnell MD Andrew Fang MD Robert Lor Randall MD Tina H. Tran BS Christin New BA Rosanna L. Wustrack MD other members of Study Group FORCE 《Journal of surgical oncology》2023,127(1):148-158
4.
目的分析超长住院患者分布及影响因素,探讨减少超长住院日的措施。方法从江苏省某三甲医院病案管理系统中调取2020年1月1日-2020年12月31日134016例出院患者的住院病案首页资料,对住院时间≥30天的1401例超长住院患者的分布特征进行统计描述,采用Logistic回归模型分析超长住院日的影响因素。结果2020年全院平均住院日为7.13天,其中超长住院患者平均住院日为41.85天。超长住院患者以60岁以上年龄组最多(39.61%);出院科室主要分布在血液科(42.18%)、普通外科(11.85%)、骨科(7.49%)等;疾病类别主要为肿瘤(47.32%)、影响健康状态和与保健机构接触的因素(10.56%)、循环系统疾病(7.07%)等;多因素Logistic回归结果显示,男性(OR=1.188)、离院方式为非医嘱离院或其他(OR=2.046)和死亡病例(OR=3.362)是超长住院的危险因素。结论控制超长住院日对平均住院日影响显著,医院应加强重点人群、重点科室和重点病种管理提高诊疗管理水平,缩短平均住院日。 相似文献
6.
目的探讨经尿道膀胱肿瘤二次电切术(Re-TURBT)在降低Ta和T1期非肌层浸润性膀胱癌(NMIBC)电切术后肿瘤复发率的临床价值。 方法回顾性分析2015年2月至2018年11月我院86例诊断为Ta和T1期的NMIBC患者。患者接受单次经尿道膀胱肿瘤电切术为对照组(40例),接受二次经尿道膀胱肿瘤切除术为观察组(46例),两组患者首次电切术中均联合了吉西他滨即刻膀胱灌注化疗。统计观察组二次电切的阳性率及肿瘤分期分级变化情况,同时比较两组患者术后2年内的肿瘤复发及进展情况。 结果两组患者年龄、性别、吸烟史、肿瘤最大径、肿瘤个数、首次电切病理分期比较差异无统计学意义(P>0.05)。观察组二次电切术后的病理结果显示,11例(23.91%)检出残余癌,5例出现临床分期升级,4例病理分级升级。观察组术后2年总复发率低于对照组(P<0.05)。两组术后2年总进展率差异无统计学意义(P>0.05)。 结论Re-TURBT可明显降低Ta和T1期NMIBC电切术后肿瘤复发率,同时可获得更准确的肿瘤分期,具有一定的临床价值。 相似文献
7.
Karhanová Marta Kalitová Jana Kovář Radim Schovánek Jan Karásek David Čivrný Jakub Hübnerová Petra Mlčák Petr Šín Martin 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2022,260(12):3977-3984
Graefe's Archive for Clinical and Experimental Ophthalmology - The purpose was to ascertain if any relation exists between the elevated intraocular pressure (IOP) in patients with... 相似文献
8.
9.
Jos B. Poell Leon J. Wils Arjen Brink Ralf Dietrich Christine Krieg Eunike Velleuer Ilkay Evren Elisabeth R. Brouns Jan G. de Visscher Elisabeth Bloemena Bauke Ylstra Ruud H. Brakenhoff 《International journal of cancer. Journal international du cancer》2023,152(2):227-238
Oral squamous cell carcinomas (OSCCs) develop in genetically altered epithelium in the mucosal lining, also coined as fields, which are mostly not visible but occasionally present as white oral leukoplakia (OL) lesions. We developed a noninvasive genetic assay using next-generation sequencing (NGS) on brushed cells to detect the presence of genetically altered fields, including those that are not macroscopically visible. The assay demonstrated high accuracy in OL patients when brush samples were compared with biopsies as gold standard. In a cohort of Fanconi anemia patients, detection of mutations in prospectively collected oral brushes predicted oral cancer also when visible abnormalities were absent. We further provide insight in the molecular landscape of OL with frequent changes of TP53, FAT1 and NOTCH1. NGS analysis of noninvasively collected samples offers a highly accurate method to detect genetically altered fields in the oral cavity, and predicts development of OSCC in high-risk individuals. Noninvasive genetic screening can be employed to screen high-risk populations for cancer and precancer, map the extension of OL lesions beyond what is visible, map the oral cavity for precancerous changes even when visible abnormalities are absent, test accuracy of promising imaging modalities, monitor interventions and determine genetic progression as well as the natural history of the disease in the human patient. 相似文献
10.
Schwab Sarah M. Carver Nicole S. Forman Maia H. Abney Drew H. Davis Tehran J. Riley Michael A. Paxton Alexandra Silva Paula L. 《Journal of developmental and physical disabilities》2022,34(2):255-277
Journal of Developmental and Physical Disabilities - Caregiver support is an important contextual factor in the daily functioning of children with cerebral palsy (CP), but few studies have examined... 相似文献