全文获取类型
收费全文 | 46445篇 |
免费 | 3650篇 |
国内免费 | 2066篇 |
专业分类
耳鼻咽喉 | 431篇 |
儿科学 | 884篇 |
妇产科学 | 447篇 |
基础医学 | 3376篇 |
口腔科学 | 1591篇 |
临床医学 | 5432篇 |
内科学 | 6723篇 |
皮肤病学 | 1170篇 |
神经病学 | 2057篇 |
特种医学 | 2284篇 |
外科学 | 6808篇 |
综合类 | 8100篇 |
现状与发展 | 10篇 |
一般理论 | 4篇 |
预防医学 | 5440篇 |
眼科学 | 1030篇 |
药学 | 3123篇 |
32篇 | |
中国医学 | 2602篇 |
肿瘤学 | 617篇 |
出版年
2024年 | 129篇 |
2023年 | 943篇 |
2022年 | 1478篇 |
2021年 | 2269篇 |
2020年 | 2164篇 |
2019年 | 1623篇 |
2018年 | 1571篇 |
2017年 | 1552篇 |
2016年 | 1812篇 |
2015年 | 1664篇 |
2014年 | 3370篇 |
2013年 | 3414篇 |
2012年 | 3078篇 |
2011年 | 3189篇 |
2010年 | 2677篇 |
2009年 | 2444篇 |
2008年 | 2247篇 |
2007年 | 2259篇 |
2006年 | 1964篇 |
2005年 | 1768篇 |
2004年 | 1442篇 |
2003年 | 1315篇 |
2002年 | 1068篇 |
2001年 | 1001篇 |
2000年 | 774篇 |
1999年 | 638篇 |
1998年 | 576篇 |
1997年 | 476篇 |
1996年 | 358篇 |
1995年 | 425篇 |
1994年 | 352篇 |
1993年 | 254篇 |
1992年 | 257篇 |
1991年 | 222篇 |
1990年 | 172篇 |
1989年 | 188篇 |
1988年 | 167篇 |
1987年 | 162篇 |
1986年 | 138篇 |
1985年 | 106篇 |
1984年 | 83篇 |
1983年 | 47篇 |
1982年 | 55篇 |
1981年 | 34篇 |
1980年 | 35篇 |
1979年 | 47篇 |
1978年 | 26篇 |
1977年 | 32篇 |
1976年 | 28篇 |
1975年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
目的:探讨经脐单孔腹腔镜手术(LESS)在妇科良性疾病中的临床价值。方法:选择2018年1月-2019年4月在我院妇科行经脐单孔腹腔镜手术的68例患者为研究组,同期同病种行传统多孔腹腔镜手术的70例患者为对照组,比较2组的术中出血量、术后最高体温、术后肛门排气时间、术后下床活动时间、术后住院时间、术后24 h疼痛视觉模拟评分(VAS)、体象量表BIS评分和切口美观满意度CS评分、手术时间及围手术期并发症的指标。结果:2组患者手术均顺利完成,术中不需要辅助操作,未中转开腹。术中、术后均未出现严重的手术并发症。2组患者在术中出血量、术后最高体温、术后排气时间、术后下床活动时间、术后住院时间差异无统计学意义(P>0.05);手术时间、术后24 h VAS评分、体象量表BIS评分和切口美观满意度CS评分比较差异有统计学意义(P<0.05)。结论:常规器械经脐单孔腹腔镜不需要特殊的器械和设备,符合卫生经济学特点;具有良好的美容效果,以及标本取出方便的优势,LESS应用于妇科良性疾病是安全可行的。 相似文献
32.
Nirmanmoh Bhatia Buddhadeb Dawn Tariq S. Siddiqui Marcus F. Stoddard 《Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital》2015,42(1):16-24
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index. 相似文献
33.
Treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted by drug delivery to the back of the eye. In recent years, concerted efforts in drug delivery have been made to prolong the residence time of drugs injected in the vitreous humor of the eye. Our previous studies demonstrated that poly(ortho ester) (POE) nanoparticles were biodegradable/biocompatible and were capable of long-term sustained release. The objective of the present study was to investigate the safety and localization of POE nanoparticles in New Zealand white rabbits and C57BL/6 mice after intravitreal administration for the treatment of chronic posterior ocular diseases. Two concentration levels of POE nanoparticles solution were chosen for intravitreal injection: 1.5?mg/ml and 10?mg/ml. Our results demonstrate that POE nanoparticles were distributed throughout the vitreous cavity by optical coherence tomography (OCT) examination 14 days post-intravitreal injection. Intraocular pressure was not changed from baseline. Inflammatory or adverse effects were undetectable by slit lamp biomicroscopy. Furthermore, we demonstrate that POE nanoparticles have negligible toxicity assessed at the cellular level evidenced by a lack of glia activation or apoptosis estimation after intravitreal injection. Collectively, POE nanoparticles are a novel and nontoxic as an ocular drug delivery system for the treatment of posterior ocular diseases. 相似文献
34.
目的探讨低分子肝素钙预防腰椎退行性疾病术后深静脉血栓形成(DVT)的有效性和安全性。方法回顾性分析广安市广安区人民医院68例腰椎退行性疾病患者的临床资料,术后均采用抗凝预防血栓形成,按照术后预防DVT所采用方式的不同分为对照组和低分子肝素钙组。分析比较2组患者术后引流量、切口愈合情况、DVT发生率、皮下瘀斑情况、血小板数值、凝血功能、D-二聚体。结果术后2组患者引流量、切口愈合情况、皮下瘀斑情况、凝血功能相关指标比较,差异无统计学意义(P>0.05)。术前和术后1、10 d 2组患者血小板数量的变化差异无统计学意义(P>0.05)。DVT发生率2组患者比较差异有统计学意义(P<0.05)。术前及术后1 d 2组患者D-二聚体比较,差异无统计学意义(P>0.05);术后10 d,对照组患者D-二聚体显著增加,2组比较差异有统计学意义(P<0.05)。结论腰椎退行性疾病术后使用低分子肝素钙进行抗凝,可以显著降低DVT的发生率,具有良好的安全性。 相似文献
35.
36.
John Lennon Silva Cunha Amanda Almeida Leite Thamiris de Castro Abrantes Lorena Passoni Vervloet Thayn Melo de Lima Morais Gerson de Oliveira Paiva Neto Tatiana Nayara Librio Kimura Snia Maria Soares Ferreira Ricardo Luiz Cavalcanti de Albuquerque‐Júnior Aline Corrêa Abraho Mario Jos Romaach Bruno Augusto Benevenuto de Andrade Oslei Paes de Almeida Ciro Dantas Soares 《Journal of cutaneous pathology》2021,48(1):24-33
37.
38.
基于温病学理论,探讨新型冠状病毒肺炎的中医病因病机与诊治思路。温病学说源于明清之前的历代中医理论积累,经过长期的温热病防治实践而形成,其对于外感热病(包括烈性传染病)的病因病机、证治方药有着较为系统的论述,近年来在我国的新发传染病防治中发挥出积极的作用。温瘟相通,瘟疫病因多为热毒疫邪,表现为热证阳证,可按温病学中的卫气营血或三焦辨证分期论治,或治以吴又可、庞安时等的经方验方,这些因、机、证、治理论可试用于新型冠状病毒肺炎的中医诊疗。且肺与大肠相表里,胃肠道也是新型冠状病毒侵袭或繁殖的部位,采用中医清热通下之法,使邪从肠道而出,可能是减轻体内病毒感染与肺脏炎症的一种途径。 相似文献
39.
Anna C. Rienmüller Sandro M. Krieg Franziska A. Schmidt Elias L. Meyer Bernhard Meyer 《The spine journal》2019,19(1):113-120
Background Context
The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).Purpose
The present study aimed to evaluate the longitudinal revision rates following dynamic pedicle screw stabilization in the lumbar spine and to determine specific risk factors predictive for ASD, SL, and overall reoperation in a large cohort with considerable follow-up.Design
We carried out a post hoc analysis of a prospectively collected database in a level I spine center.Patients Example
The patient sample comprised 283 (151 female/132 male) consecutive patients suffering from painful degenerative lumbar segmental instability with or without spinal stenosis who underwent DS of the lumbar spine (Ulrich Cosmic, Ulrich Medical, Ulm, Germany) between January 2008 and December 2011.Outcome Measures
Longitudinal reoperation rate and risk factors predictive for revision surgery were evaluated.Methods
We analyzed the longitudinal reoperation rate due to ASD and SL and overall reoperation. Risk factors such as age, gender, body mass index, lumbar lordosis (LL), number of segments, and number of previous surgeries were taken into account. Regular and mixed model logistic regressions were performed to determine risk factors for revision surgery on a patient and on a screw level.Results
The mean age was 65.7±10.2 years (range 31–88). One hundred thirty-two patients were stabilized in 1 segment, 134 in 2 segments, 15 in 3 segments, and 2 patients in 4 segments. Reoperation rate for ASD and SL after 1 year was 7.4 %, after 2 years was 15.0%, and after a mean follow-up of 51.4±15 months was 22.6%. Reasons for revision were SL in 19 cases (6.6%), ASD in 39 cases (13.7%), SL and ASD in 6 cases, hematoma in 2 cases (0.7%), cerebrospinal fluid fistulae in 3 cases (1.1%), infection in 6 cases (2.1%), and implant failure in 1 case (0.4%). The patients' age, the number of stabilized segments, and the number of previous surgeries and postoperative LL had a significant influence on the probability for revision surgery.Conclusions
Reoperation rates after DS of the lumbar spine are comparable with rigid fixations. The younger the patient and the more segments are involved, the lower the LL and the more previous surgeries were found, the higher was the risk of revision. Risk of revision was almost twice as high in men compared with women. We therefore conclude that for clear clinical indication and careful evaluation of preoperative imaging data, DS using the Cosmic system seems to be a possible option. The presented data will help to further tailor indication and patient selection. 相似文献40.
Salaam Semaan 《Emerging infectious diseases》2016,22(10):1863-1864