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   1998篇
  免费   711篇
  国内免费   114篇
耳鼻咽喉   19篇
儿科学   39篇
妇产科学   28篇
基础医学   169篇
口腔科学   24篇
临床医学   304篇
内科学   329篇
皮肤病学   47篇
神经病学   131篇
特种医学   138篇
外科学   299篇
综合类   225篇
现状与发展   1篇
预防医学   411篇
眼科学   153篇
药学   159篇
  4篇
中国医学   174篇
肿瘤学   169篇
  2024年   61篇
  2023年   124篇
  2022年   311篇
  2021年   407篇
  2020年   308篇
  2019年   226篇
  2018年   201篇
  2017年   196篇
  2016年   169篇
  2015年   239篇
  2014年   273篇
  2013年   35篇
  2012年   24篇
  2011年   32篇
  2010年   25篇
  2009年   13篇
  2008年   25篇
  2007年   31篇
  2006年   19篇
  2005年   15篇
  2004年   12篇
  2003年   9篇
  2002年   17篇
  2001年   8篇
  2000年   9篇
  1999年   12篇
  1998年   2篇
  1997年   9篇
  1992年   3篇
  1991年   3篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1974年   2篇
排序方式: 共有2823条查询结果,搜索用时 15 毫秒
41.
42.
目的 观察双腔气管导管(double-lumen endotracheal tube,DLT)塑型对插管成功率及术后声音嘶哑(声嘶)、咽喉痛的影响,从而为寻求更好的DLT塑型插管提供依据. 方法 择期全身麻醉下行胸科手术患者160例,美国麻醉医师协会(ASA)分级Ⅰ~Ⅲ级,参照随机数字表法分成DLT插管塑型组和非塑型组(每组80例),两组根据左右DLT插管各分为两组(A、B、C、D组,每组40例),又根据性别再各分为两个亚组(A1、A2、B1、B2、C1、C2、D1、D2组,每组20例).两组均采用经口明视气管插管,塑型组采用塑成“J”状的DLT进行插管,非塑型组采用未经塑型保留原有弯度的DLT进行插管.观察DLT插管时间、插管尝试次数及插反情况,患者术后声嘶、咽喉痛发生率及严重程度. 结果 塑型组插管时间[(154±6)s]明显短于非塑型组[(185±13)s](P<0.05);塑型组插管尝试次数[(1.4±0.4)次]明显少于非塑型组[(1.7±0.8)次](P<0.05);塑型组插反情况(3次)明显比非塑型组少(11次)(P<0.05),且与性别无关,但左DLT比右DLT易于插反(P<0.05).患者术后声嘶发生率塑型组(15/80)明显低于非塑型组(33/80)(P<0.05);患者术后咽喉痛发生率塑型组(15/80)明显低于非塑型组(31/80) (P<0.05),且与性别有关,女性较男性术后易发生声嘶、咽喉痛. 结论 “J”状DLT塑型插管成功率高、刺激小,可降低患者术后声嘶、咽喉痛发生率,具有一定的临床推广意义.  相似文献   
43.
Background:In qualitative diagnosis of bile duct stenosis,single diagnostic measure is difficult to make a correct diagnosis,to combine several diagnostic techniques may be helpful to make an accurate ...  相似文献   
44.
三国时代魏张揖编著的《广雅》中收录有医学词汇,清代训诂大家王念孙所著的《广雅疏证》是《广雅》最好的注本,最注重以声音通训诂、系联同源词,以此对词义进行训释,沟通词际关系。以《广雅》中收录的医学词汇为语料,挖掘王念孙在《广雅疏证》中训释医词时所使用的破通假、系同源、沟通普通词汇与医学词汇等理论、方法,并结合王念孙在校勘《广雅》文本中存在的误字、脱文、衍文等问题时采用的校勘学方法,从中探索当今医学词汇研究可以借鉴的释词方法。  相似文献   
45.
The purpose of the study is to investigate the effects of electrospun fiber diameter and orientation on differentiation and ECM organization of bone marrow stromal cells (BMSCs), in attempt to provide rationale for fabrication of a periosteum mimetic for bone defect repair. Cellular growth, differentiation, and ECM organization were analyzed on PLGA‐based random and aligned fibers using fluorescent microscopy, gene analyses, electron scanning microscopy (SEM), and multiphoton laser scanning microscopy (MPLSM). BMSCs on aligned fibers had a reduced number of ALP+ colony at Day 10 as compared to the random fibers of the same size. However, the ALP+ area in the aligned fibers increased to a similar level as the random fibers at Day 21 following stimulation with osteogenic media. Compared with the random fibers, BMSCs on the aligned fibers showed a higher expression of OSX and RUNX2. Analyses of ECM on decellularized spun fibers showed highly organized ECM arranged according to the orientation of the spun fibers, with a broad size distribution of collagen fibers in a range of 40–2.4 μm. Taken together, our data support the use of submicron‐sized electrospun fibers for engineering of oriented fibrous tissue mimetic, such as periosteum, for guided bone repair and reconstruction. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1382–1389, 2013  相似文献   
46.
The study was aimed to evaluate the effects of levothyroxine (LT4) supplemental replacement treatment for pregnancy and analyze the associations between the clinical classification of hypothyroidism and reduced thyroid-stimulating hormone (TSH) in LT4 therapy. Totally, 195 pregnant women with hypothyroidism receiving routine prenatal care were enrolled. They were categorized into three groups: overt hypothyroidism (OH), subclinical hypothyroidism (SCH) with negative thyroperoxidase antibody (TPOAb), and SCH with positive TPOAb. The association between the clinical classification and reduced TSH in LT4 supplemental replacement treatment was assessed. The results indicated that reduced TSH was significantly different among the groups according to the clinical classifications (p?=?0.043). The result was also significantly different between patients with OH and patients with SCH and negative TPOAb (p?=?0.036). Similar result was reported for the comparison between patients with OH and patients with SCH and positive TPOAb (p?=?0.016). Multiple variable analyses showed that LT4 supplementation, gestational age and the variable of clinical classifications were associated with reduced TSH independently. Our data suggested that the therapeutic effect of substitutive treatment with LT4 was significantly associated with different clinical classifications of hypothyroidism in pregnancy and the treatment should begin as soon as possible after diagnosis.  相似文献   
47.
48.
Li  Jianguo  Lyu  Liang  Chen  Cheng  Yin  Senlin  Jiang  Shu  Zhou  Peizhi 《Neurosurgical review》2022,45(3):2201-2210

Microvascular decompression (MVD) is the first choice of surgery for hemifacial spasm (HFS). MVD surgery for vertebral artery (VA)-associated HFS is more difficult than for non-VA-associated HFS. There is controversy about the cure rate and complication of MVD for HFS in previous studies. We searched PubMed, Web of Science, and Embase for relevant publications. Based on the search results, we compared the outcomes of MVD for VA-associated HFS and non-VA-associated HFS. At the same time, we analyzed spasm-free rates and the complications and assessed the relationship between VA-associated HFS and gender, left side, and age. For analysis, six studies that included 2952 patients in the VA-associated group and 604 in the non-VA-associated group were selected. The effective rate of MVD was not significantly different between both groups (OR?=?1.16, 95% CI 0.81–1.67, P?=?0.42). Compared to non-VA-associated group, the transient complications (OR?=?0.64, 95% CI 0.46–0.89, P?=?0.008) and permanent complications (OR?=?0.28, 95% CI 0.15–0.54, P?=?0.0001) occurred more frequently in VA-associated group. The rate of hearing loss was significantly higher in VA-associated HFS than non-VA-associated HFS (OR?=?0.35, 95% CI 0.19–0.64, P?=?0.0007); the facial paralysis after operation was not significantly different between both groups (OR?=?1.25, 95% CI 0.91–1.72, P?=?0.17). There were older patients (WMD?=?3.67, 95% CI 3.29–4.05, P?<?0.00001) and more left-sided HFS (OR?=?0.23, 95% CI 0.19???0.29, P?<?0.0002) in the VA-associated HFS group than non-VA-associated HFS group, while the non-VA-associated HFS group was female-dominated (OR?=?1.58, 95% CI 1.32???1.89, P?<?0.00001). Both groups achieved good results in MVD cure rates. In VA-associated HFS, the complication rate of decompression and the rate of hearing loss after operation were higher than in non-VA-associated HFS, but the facial paralysis after operation was similar in both groups, and most complications were transient and disappeared during follow-up. VA-associated HFS is more prevalent in older adults, less prevalent in women, and more predominantly left-sided. More clinical studies are needed to better compare the efficacy and complication of MVD between both groups.

  相似文献   
49.
目的探讨利用碘化钾制备碘涂层钛板的可行性,并验证其抗菌性能。方法以碘化钾作为电解液,使用电泳沉积法将碘负载到钛板表面,制备出碘涂层钛板。通过扫描电镜与能谱分析,观察碘涂层钛板的表面征象和成分结构。实验分组:对照组是经过预处理但未行载碘的钛板,共10块;实验组是经过预处理后再行载碘的碘涂层钛板,根据电解液浓度的不同分为3组:1000 mg/L、2000 mg/L、4000 mg/L组,每组各10块。使用1×106 CFU/mL的金黄色葡萄球菌(ATCC25923)进行体外抗菌实验,并对其抗菌性能进行研究。结果碘涂层钛板外观呈灰色,表面可均匀覆盖一层平整、无塌陷的涂层,电镜下见其表面可形成碘涂层,局部散在分布大小不等的不规则陷凹。对照组、1000 mg/L组、2000 mg/L组、4000 mg/L组的钛板碘含量分别为0、5.10、10.32、15.05 mass%;其体外抗菌菌落计数分别为56.00±5.09、21.40±2.76、9.10±2.51和2.00±1.88,4组之间菌落计数比较差异均有统计学意义(P<0.05)。结论碘化钾作为电解液,使用电泳沉积法可成功制备出碘含量稳定、涂层分布均匀的碘涂层钛板。体外抗菌实验证明碘涂层钛板的抗菌性能强于未载碘钛板。  相似文献   
50.
目的比较人肝、肾ABO血型抗原表达的差异,探索ABO血型抗原在血型抗体介导排斥反应中的作用。 方法ABO血型为A型和B型血的公民逝世后器官捐献供者各4例,O型血对照2例。获取供者肝脏和双肾后,留取肾动脉、肾静脉、肾组织、肝动脉、肝静脉、门静脉和肝组织标本,运用蛋白质印迹法(WB)和免疫组织化学法检测ABO血型抗原的含量和分布。 结果WB检测结果显示,同一供者不同部位ABO血型抗原含量并不一致。在同一个体内,A型抗原在肾组织和门静脉含量最高,在肾动脉含量最低;B型抗原在肝静脉及肾组织含量最高,在肾动脉、肾静脉及肝组织含量最低。不同个体之间,同一部位血型抗原含量差别也较大。通过免疫组织化学法检测,进一步发现血型抗原在肝、肾组织和血管中的分布与WB结果基本一致。 结论ABO血型抗原在不同血型、个体和器官之间均存在不同程度差异,这种差异也可能会影响ABO血型不相容器官移植的结局。  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