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   2822篇
  免费   225篇
  国内免费   45篇
耳鼻咽喉   23篇
儿科学   90篇
妇产科学   44篇
基础医学   240篇
口腔科学   43篇
临床医学   272篇
内科学   434篇
皮肤病学   20篇
神经病学   182篇
特种医学   96篇
外国民族医学   1篇
外科学   371篇
综合类   295篇
预防医学   245篇
眼科学   39篇
药学   395篇
  4篇
中国医学   212篇
肿瘤学   86篇
  2024年   11篇
  2023年   89篇
  2022年   95篇
  2021年   160篇
  2020年   155篇
  2019年   188篇
  2018年   205篇
  2017年   141篇
  2016年   111篇
  2015年   106篇
  2014年   151篇
  2013年   190篇
  2012年   129篇
  2011年   148篇
  2010年   104篇
  2009年   103篇
  2008年   94篇
  2007年   84篇
  2006年   86篇
  2005年   72篇
  2004年   51篇
  2003年   46篇
  2002年   43篇
  2001年   48篇
  2000年   22篇
  1999年   25篇
  1998年   24篇
  1997年   13篇
  1996年   11篇
  1995年   13篇
  1994年   11篇
  1993年   7篇
  1992年   9篇
  1991年   12篇
  1990年   8篇
  1989年   13篇
  1988年   9篇
  1987年   8篇
  1985年   30篇
  1984年   57篇
  1983年   36篇
  1982年   28篇
  1981年   27篇
  1980年   29篇
  1979年   22篇
  1978年   21篇
  1977年   6篇
  1976年   14篇
  1974年   7篇
  1973年   7篇
排序方式: 共有3092条查询结果,搜索用时 15 毫秒
41.
This paper uses the standard error of measurement (SEM) and the standard error of the difference (S(diff)) in relation to data on individuals with amyotrophic lateral sclerosis (ALS) to calculate the minimum change scores required by statistical criteria for each dimension of the Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40). Data collected from a longitudinal study was used to evaluate the usefulness of SEM and S(diff) criteria and to compare these criteria with an anchor-based approach in determining meaningful change. Questionnaires were completed on two occasions, 3 months apart. 764 questionnaires were returned. Questionnaires included the ALSAQ-40 and dimension specific transition items. The ALSAQ-40 is a disease specific health-related quality of life instrument for use in studies of patients with ALS or other motor neuron diseases. For all dimensions of the ALSAQ-40 the patterns of SEMs were similar over time. The results suggest that, for example, six points change on a 0-100 transformed scoring of the physical mobility dimension may be considered on distributional grounds a minimum meaningful change. The demonstrated consistency of SEMs for the dimensions of the ALSAQ-40 is empirical evidence of the theoretically claimed advantage of this measure of sample independence, and supports use of this distributional approach to calculate meaningful change.  相似文献   
42.
傅坤发  刘乃丰 《现代医学》2006,34(5):301-304
目的观察急性冠脉综合征(ACS)患者不同情况下血浆C型钠尿肽(CNP)水平,探讨CNP在ACS发病过程中的意义。方法用放射免疫分析法检测35例ACS患者经皮冠脉介入治疗(PC I)术前、术后24 h血浆CNP水平,并与20例正常对照组血浆CNP进行对比。观察并分析ACS患者PC I前血浆CNP水平与心功能及冠脉狭窄积分间的关系。结果ACS患者入院时血浆CNP水平高于正常对照组[(6.8±1.4)pg.m l-1vs(5.1±1.6)pg.m l-1,P<0.01],且PC I后24 h血浆CNP的水平较术前明显增高[(10.9±2.9)pg.m l-1vs(6.8±1.4)pg.m l-1,P<0.001]。PC I前左室射血分数(LVEF)<50%的患者血浆CNP水平明显高于LVEF>50%的患者[(7.8±1.1)pg.m l-1vs(6.1±1.2)pg.m l-1,P<0.001],但是血浆CNP水平与心功能分级(NYHA)未见相关性。冠脉Gensin i积分与PC I前血浆CNP水平呈高度正相关(r=0.76,P<0.001)。结论ACS患者血浆CNP水平明显增高,介入治疗后ACS患者血浆CNP水平继续增高,CNP在ACS发病中的意义值得进一步研究。  相似文献   
43.
探讨硬膜外自控镇痛在脊柱内镜手术应用的临床效果。选择120例脊柱内镜手术治疗腰椎间盘突出症患者,随机分为对照组(0.2%罗哌卡因+0.2%利多卡因局麻),0.1%罗哌卡因+舒芬太尼组(0.1%罗哌卡因+0.3 μg/mL舒芬太尼硬膜外自控镇痛),0.2%罗哌卡因+舒芬太尼组(0.2%罗哌卡因+0.3 μg/mL舒芬太尼硬膜外自控镇痛),采用视觉模拟(VAS)评分法评估手术中镇痛效果,采用改良Bromage 评分评估术毕运动神经阻滞程度,统计0.1%罗哌卡因+舒芬太尼组和0.2%罗哌卡因+舒芬太尼组自控镇痛泵(PCA)按压次数和用药量。结果显示0.2%罗哌卡因和0.3 μg/mL舒芬太尼硬膜外自控镇痛应用于脊柱内镜手术,可以达到明显的镇痛效果,满足手术需要,又同时保留患者双下肢运动功能,即有“感觉和运动阻滞分离”现象,从而避免脊柱内镜下马尾神经损伤的可能,值得在临床上推广。  相似文献   
44.
目的探讨提上睑肌缩短术联合 Mustarde 双 Z 形切除术矫正儿童小睑裂综合征(blepharophimosis-ptosis-epicanthus inversus syndrome,BPES)的疗效。方法2015 年 3 月—2017 年 6 月,采用提上睑肌缩短术联合 Mustarde 双 Z 形切除术一期矫正 26 例儿童双眼 BPES。其中,男 16 例,女 10 例;年龄 4~14 岁,平均 7 岁。均有典型的小睑裂四联征。7 例伴有鼻梁低平,20 例伴有弱视和斜视。睑裂长度(19.5±4.5)mm,睑裂宽度(2.5±1.6)mm,内眦间距(42.1±6.5)mm,提上睑肌肌力(5.5±1.3)mm。结果术后切口均Ⅰ期愈合。23 例获随访,随访时间 2~12 个月,平均 10 个月。其中 2 例矫正不足、3 例过度矫正,6 例眼睑线弧度欠佳,均无眼睑内外翻和角膜炎发生。其余患儿均成功矫正上睑下垂和内眦赘皮,眼睑线弧度自然。术后 7 d 测量睑裂长度(27.2±1.9)mm,睑裂宽度(12.5±1.3)mm,内眦间距(29.4±2.6)mm;以上指标均较术前显著改善,差异有统计学意义(t=0.127,P=0.042;t=0.341,P=0.029;t=0.258,P=0.038)。术后无因睑裂宽度、长度回退导致的成角畸形发生。 结论提上睑肌缩短术联合 Mustarde 双 Z 形切除术能达到一期矫正儿童 BPES 目的,可获得较好临床疗效。  相似文献   
45.
46.
Abstract

Maize flours and dough were variously prepared from whole, decorticated, and alkaline-cooked maize grains. Other flour types include soycorn milk residue and wheat flours. All the flour types were made into base for pie-type preparations. Tofu (soybean curd) cubes were mixed with local pepper and onion condiments, fried, and were used for pie filling. The various pie types namely WFTP, DMFTP, WMFTP, WMADTP, DMADTP, SRFTP and MPI-MPVI (MPs) represent pie types made from base using wheat, decorticated, whole maize flours, wet and dry masa doughs, soycorn residue flour, and market pies 1 to VI, respectively. MP1 was used as control for sensory evaluation. The protein content of the maize-based pies ranged from 19.54 to 34.13% and was significantly higher (P < 0.01) than the range of protein content 11.67–15.53% for the MPs. Except for WMFTP, all other experimental pie types gave higher in vitro digestibility (IVD) percent than the MPs. The sensory evaluation scores showed that none of the experimental pies were rejected but their scores were significantly lower (P < 0.05) than those for the MPs in all the parameters measured. Pie types WFTP, DMFTP, and WMFTP were significantly higher (P < 0.05) than the other experimental pies in all the sensory attributes measured. The consumption of tofu pies developed in this study, using the improved home-level technology described, will help to reduce malnutrition consequent to the high protein content and nutritional attributes of the improved local snack. doi:10.1300/J385v05n02_07  相似文献   
47.
Intravascular levels of low-density lipoprotein cholesterol (LDL-C) at approximately ≤ 0.6 mmol/L are likely to minimize, and perhaps eliminate, LDL-C-related vascular toxicity while having no effect on essential, intracellular cholesterol homeostatic pathways, according to accumulated knowledge from basic science. Randomized clinical trials, observational reports, and Mendelian randomization trials are also forcing a reconsideration of what “normal” LDL-C means. Recent trials of secondary prevention have substantiated that such levels are safe and associated with a decreased risk of cardiovascular events (CVEs) compared with patients with higher levels of LDL-C. Similarly, treatment to this low range is associated with regression and stabilization of established atherosclerosis. Primary prevention trials also show that low levels of LDL-C are safe and associated with decreased risk of CVEs through cholesterol-lowering in adults with LDL-C ≥ 3.5 mmol/L or when levels are < 3.5 mmol/L in association with other cardiovascular risks. Although there are no randomized clinical outcome trials of familial hypercholesterolemia patients, such patients have very high, lifetime risk of CVE, and registry studies show that LDL-C reduction has nearly normalized their CVE rates. The possibility of familial hypercholesterolemia should be considered if LDL-C is > 4.5 and > 4.0 mmol/L at ages 18-39 years and younger than 18 years, respectively. On the basis of these convergent and internally consistent lines of evidence, in this article we speculate on a translational paradigm aimed at eliminating LDL-C-related CVEs through aggressive primary prevention strategies that are already proven and well accepted in principle.  相似文献   
48.
49.
《Saudi Dental Journal》2021,33(7):533-537
Context.Proteins in the saliva are one of the defense mechanism factors that can protect the oral cavity from disease. However, smoking might affect the properties of saliva.AimTo determine the differences in salivary protein profiles and total concentrations in smokers and non-smokers and their correlation with dental caries severity as indicated by the Decayed, Missing, Filled-Teeth (DMF-T) scores.Methods and materialThis cross-sectional study included 25 smokers and 25 non-smokers. The DMF-T scores were recorded. The total salivary protein was measured by the Bradford method, and the profile proteins were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).ResultsThe average of salivary protein concentration in smokers was lower than that in non-smokers (551.486 µg/mL versus 765.361 µg/mL), but the difference was not statistically significant (P > 0.05). Further correlation analyses showed a negative correlation between the concentration of proteins based on the extent of smoking. A weak negative correlation was found between protein concentration and DMF-T scores (r = −0.239). Dominant salivary protein bands of 11.6 kDa and 54.5 kDa were found in smokers and 27 kDa, 60 kDa, and 94.5 kDa were found in non-smokers.ConclusionDifferent protein bands appeared in smokers and non-smokers. There was a weak correlation between protein concentration, DMF-T scores, and the extent of smoking.  相似文献   
50.
Brian Day 《Arthroscopy》2018,34(8):2511-2513
Personalized (based on a percentage of a patient's limb occlusion pressure) blood flow restriction is emerging as a potential advancement in orthopaedic surgery. Safe application of the technology requires the use of medical devices capable of customizing the pressures applied to individual patients. In those circumstances, it is a low risk and noninvasive technique. By limiting muscle atrophy and aiding in the recovery of strength and function, it has the potential to significantly reduce the morbidity from limb trauma and surgery, and aid in achieving a substantially earlier return to full activity.  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