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1.
Multilevel models have long been used by health geographers working on questions of space, place, and health. Similarly, health geographers have pursued interests in determining whether or not the effect of an exposure on a health outcome varies spatially. However, relatively little work has sought to use multilevel models to explore spatial variability in the effects of a contextual exposure on a health outcome. Methodologically, extending multilevel models to allow intercepts and slopes to vary spatially is straightforward. The purpose of this paper, therefore, is to show how multilevel spatial models can be extended to include spatially varying covariate effects. We provide an empirical example on the effect of agriculture on malaria risk in children under 5 years of age in the Democratic Republic of Congo.  相似文献   
2.
Information on the common carotid artery and cerebral microcirculation can be obtained by micro-ultrasound (µUS). The aim of the study described here was to investigate high-fat diet-induced alterations in vascular parameters in ApoE–/– mice. Twenty-two ApoE–/– male mice were examined by µUS and divided into the standard diet (ApoE–/–SD) and high-fat diet (ApoE–/–HF) groups. The µUS examination was repeated after 4 mo (T1). Carotid stiffness, reflection magnitude and reflection index were measured; the amplitudes of the first (W1) and second (W2) local maxima, the local minimum (Wb) and the reflection index (RIWIA?=?Wb/W1) were assessed with wave intensity analysis. At T1, ApoE–/–HF mice had increased carotid stiffness (1.48 [0.36] vs. 1.88 [0.51]) and reflection magnitude (0.89 [0.07] vs. 0.94 [0.07]) values. Longitudinal comparisons highlighted increases in carotid stiffness for ApoE–/–HF mice (from 1.37 [0.25] to 1.88 [0.51] m/s) but not for ApoE–/–SD mice (from 1.40 [0.62] to 1.48 [0.36] m/s). ApoE–/–HF mice exhibited carotid artery stiffening and increased wave reflections.  相似文献   
3.
In population‐based household surveys, for example, the National Health and Nutrition Examination Survey, households are often sampled by stratified multistage cluster sampling, and multiple individuals related by blood are often sampled within households. Therefore, genetic data collected from these population‐based household surveys, called National Genetic Household Surveys, can be correlated because of two levels of correlation. One level of correlation is caused by the multistage geographical cluster sampling and the other is caused by biological inheritance among participants within the same sampled family. In this paper, we develop an efficient Hardy Weinberg Equilibrium (HWE) test utilizing pairwise composite likelihood methods that incorporate the sample weighting effect induced by the differential selection probabilities in complex sample designs, as well as the two‐level clustering (correlation) effects described above. Monte Carlo simulation studies show that the proposed HWE test maintains the nominal levels, and is more powerful than existing methods (Li et al. 2011) under various (non)informative sample designs that depend on genotypes (explicitly or implicitly), family relationships or both, especially when within‐household sampling depends on the genotypes. The developed tests are further evaluated using simulated genetic data based on the Hispanic Health and Nutrition Survey. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
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ObjectivesThis study compared the performance of the quantitative flow ratio (QFR) with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) myocardial perfusion imaging (MPI) for the diagnosis of fractional flow reserve (FFR)−defined coronary artery disease (CAD).BackgroundQFR estimates FFR solely based on cine contrast images acquired during invasive coronary angiography (ICA). Head-to-head studies comparing QFR with noninvasive MPI are lacking.MethodsA total of 208 (624 vessels) patients underwent technetium-99m tetrofosmin SPECT and [15O]H2O PET imaging before ICA in conjunction with FFR measurements. ICA was obtained without using a dedicated QFR acquisition protocol, and QFR computation was attempted in all vessels interrogated by FFR (552 vessels).ResultsQFR computation succeeded in 286 (52%) vessels. QFR correlated well with invasive FFR overall (R = 0.79; p < 0.001) and in the subset of vessels with an intermediate (30% to 90%) diameter stenosis (R = 0.76; p < 0.001). Overall, per-vessel analysis demonstrated QFR to exhibit a superior sensitivity (70%) in comparison with SPECT (29%; p < 0.001), whereas it was similar to PET (75%; p = 1.000). Specificity of QFR (93%) was higher than PET (79%; p < 0.001) and not different from SPECT (96%; p = 1.000). As such, the accuracy of QFR (88%) was superior to both SPECT (82%; p = 0.010) and PET (78%; p = 0.004). Lastly, the area under the receiver operating characteristics curve of QFR, in the overall sample (0.94) and among vessels with an intermediate lesion (0.90) was higher than SPECT (0.63 and 0.61; p < 0.001 for both) and PET (0.82; p < 0.001 and 0.77; p = 0.002), respectively.ConclusionsIn this head-to-head comparative study, QFR exhibited a higher diagnostic value for detecting FFR-defined significant CAD compared with perfusion imaging by SPECT or PET.  相似文献   
6.
目的通过观察心身疾病患者脑电信号慢波δ和θ波的功率值改变,探究心身疾病"刚柔辨证"四种常见证候与脑电慢波改变的相关关系。方法 "证病结合""以方测证"为研究方法,采用脑电地形图为技术手段,把经显效方剂对应治疗2~8周后疗效为显效和临床痊愈的"刚柔辨证"主证为心肝火旺、心肝阴虚、肝郁气滞、肝郁脾虚证的患者治疗前脑电信号δ和θ波功率值与健康人对照组脑电信号δ和θ波功率值进行对照分析。其中心肝火旺证20例、心肝阴虚证32例、肝郁气滞证27例、肝郁脾虚证21例和健康人对照组23例。结果心肝阴虚证与正常人对照组比较,δ波在额区和额极区功率值增高(在FP1、F3、F4,P0.005;在FP2,P0.05),θ波在除了双颞区之外所有10个脑区功率值增高(P0.005)。心肝火旺证、肝郁气滞证、肝郁脾虚证与正常人对照组比较,δ波和θ波功率值增高,以前头部为主,但此三组与对照组比较未见显著性差异。结论初步揭示"刚柔辨证"四种常见证候与脑电慢波改变的规律性及特异性表现,初步从脑电生理学角度揭示"刚柔辨证"理论的物质基础和证候实质。  相似文献   
7.
目的:比较chirp声与短声ABR的V波振幅和潜伏期值,从而探讨chirp声在ABR测试时是否更具优势。方法分别用chirp声与短声两种测试声记录16例听力正常婴幼儿(24耳)的ABR,比较10~70 dB nHL不同刺激强度下两种测试声引出V波的振幅大小以及高强度和阈值强度下引出V波的潜伏期差异。结果在强度为20~70 dB nHL时,两种刺激声的V波振幅无显著差异(P>0.05);刺激声强度为10 dB nHL时,chirp声V波的引出率较短声显著增高(分别为15/24和7/24, P<0.01)。较高刺激强度时,两种测试声引出的V波潜伏期无明显差异(P>0.05);阈值水平时,chirp声ABR的V波潜伏期比短声ABR的V波潜伏期长(P<0.05)。结论本组听力正常婴幼儿ABR测试中chirp声相比短声增加V波振幅的优势并不显著,且I波和III波不如短声ABR典型;在临床应用chirp声之前还应进一步深入研究。  相似文献   
8.
ObjectivesThe objective of this study was to introduce levator scapulae (LS) measurement using a caliper and the levator scapulae index (LSI) and to investigate intra- and interrater reliability of the LSI in subjects with and without scapular downward rotation syndrome (SDRS).DesignTwo raters measured LS length twice in 38 subjects (19 with SDRS and 19 without SDRS).Main outcome measuresFor reliability testing, intraclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated.ResultsIntrarater reliability analysis resulted with ICCs ranging from 0.94 to 0.98 in subjects with SDRS and 0.96 to 0.98 in subjects without SDRS. These results represented that intrarater reliability in both groups were excellent for measuring LS length with the LSI. Interrater reliability was good (ICC: 0.82) in subjects with SDRS; however, interrater reliability was moderate (ICC: 0.75) in subjects without SDRS. Additionally, SEM and MDC were 0.13% and 0.36% in subjects with SDRS and 0.35% and 0.97% in subjects without SDRS. In subjects with SDRS, low dispersion of the measurement errors and MDC were shown.ConclusionsThis study suggested that the LSI is a reliable method to measure LS length and is more reliable for subjects with SDRS.  相似文献   
9.
IntroductionCalcaneal pitch angle and Meary’s angle are commonly used to assess longitudinal foot arches on lateral-view radiographs. The aim of this study was to examine and evaluate the radiographic longitudinal foot arch measurement methods with the best intraobserver and interobserver reliabilities for patients with (1) severe cavus deformity and (2) severe flatfoot deformity.MethodsStanding radiographic images of 22 feet with severe cavus foot deformity and 49 feet with severe flatfoot deformity were obtained to measure the longitudinal axes of the talus, first metatarsal, calcaneus and plantar surface, which were defined using six, five, four and three different methods, respectively, selected from previous reports. Intraobserver and interobserver correlation coefficients were calculated.ResultsThe results are generally consistent with those of Part 1. The best intraobserver and interobserver correlation coefficients for the tarsal axes were obtained using methods involving a line bisecting the angle formed by the lines tangential to the superior and inferior margins of the talus, a line connecting the centre of the first metatarsal head and the midpoint of the visualized base of the first metatarsal, and a line drawn tangential to the inferior surface of the calcaneus. For the plantar axis, a method that used the horizontal plane (as a reference axis) was regarded as the best approach.ConclusionsThe aforementioned methods were considered to be optimal for the radiographic assessment of longitudinal foot arches in patients with severe cavus or flatfoot deformity. This study may contribute to the more accurate assessment of any foot deformity.  相似文献   
10.
目的将传统针刺疗法中的头皮针结合空气压力波治疗仪联合现代康复运动疗法与单纯采用现代康复运动疗法治疗脑卒中后肩手综合征的疗效进行对比研究。方法入选90例脑卒中并发肩手综合征患者,用随机数字法分为对照组与治疗组,每组45例;对照组:常规用药+康复训练;治疗组:在对照组的治疗基础上加用头皮针和空气压力波治疗仪的联合治疗,30 d为1个疗程,1个疗程后将两组的观察结果进行统计和对照分析;观察指标:(1)手功能试验(Carroll评分法);(2)疼痛分级指数(pain rating index,PRI评分);(3)手掌围度(使用软尺测量)。结果对照组45例脑卒中并发肩手综合征患者中,疗程结束后总有效28例,无效17例;治疗组45例脑卒中并发肩手综合征患者中,疗程结束后总有效39例,无效6例。两组疗效比较,治疗组中有效患者明显高于对照组,差异有统计学意义(P<0.01)。治疗组脑卒中并发肩手综合征患者手功能试验Carroll评分(57.71±34.34比较46.56±24.08)与疼痛分级指数PRI评分(8.09±3.56vs.17.31±6.08)显著高于对照组脑卒中并发肩手综合征患者,差异有统计学意义(P<0.05)。治疗组脑卒中并发肩手综合征患者手掌围度有效改善率91.1%明显高于对照组脑卒中并发肩手综合征患者57.8%,差异有统计学意义(P<0.01)。结论头针联合空气压力波结合康复训练是一种治疗脑卒中后肩手综合征行之有效的方法,尤其是在缓解肢体肿胀程度上较常规康复疗法显著。  相似文献   
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