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   714篇
  免费   40篇
  国内免费   22篇
耳鼻咽喉   79篇
儿科学   58篇
妇产科学   3篇
基础医学   68篇
口腔科学   15篇
临床医学   95篇
内科学   153篇
皮肤病学   13篇
神经病学   11篇
特种医学   113篇
外科学   63篇
综合类   9篇
预防医学   38篇
眼科学   7篇
药学   35篇
肿瘤学   16篇
  2022年   2篇
  2021年   6篇
  2020年   6篇
  2019年   6篇
  2018年   10篇
  2017年   13篇
  2016年   10篇
  2015年   4篇
  2014年   14篇
  2013年   25篇
  2012年   29篇
  2011年   32篇
  2010年   29篇
  2009年   18篇
  2008年   15篇
  2007年   33篇
  2006年   20篇
  2005年   16篇
  2004年   9篇
  2003年   13篇
  2002年   8篇
  2001年   13篇
  2000年   8篇
  1999年   21篇
  1998年   41篇
  1997年   42篇
  1996年   36篇
  1995年   18篇
  1994年   27篇
  1993年   19篇
  1992年   24篇
  1991年   16篇
  1990年   13篇
  1989年   19篇
  1988年   32篇
  1987年   18篇
  1986年   12篇
  1985年   13篇
  1984年   11篇
  1983年   12篇
  1982年   17篇
  1981年   11篇
  1980年   7篇
  1979年   2篇
  1978年   3篇
  1977年   5篇
  1976年   4篇
  1975年   4篇
  1954年   2篇
  1943年   1篇
排序方式: 共有776条查询结果,搜索用时 11 毫秒
61.
Local television news is an important source of health information for the public. Yet little is known about coverage of health issues on local television newscasts. This study examined 1,863 news stories that aired on 4 English-language channels and 1 Spanish channel in 7 U.S. markets during a composite week in 2000. About 10% of news stories focused on health topics. Specific illnesses/diseases and healthy living issues received the most frequent coverage. Health news stories generally were less than 1 min long. Most health news stories were neutral in tone. Few offered contrasting viewpoints or follow-up information. Many stories were likely to require a 10th grade education to be understood. Implications for health professionals, policy makers, and health communication researchers are discussed.  相似文献   
62.
This study investigates the relationship between adverse pregnancy outcomes in high-risk African American women in Washington, DC and sociodemographic risk factors, behavioral risk factors, and the most common and interrelated medical conditions occurring during pregnancy: diabetes, hypertension, preeclampsia, and Body Mass Index (BMI). Data are from a randomized controlled trial conducted in 6 prenatal clinics. Women in their 1st or 2nd trimester were screened for behavioral risks (smoking, environmental tobacco smoke exposure, depression, and intimate partner violence) and demographic eligibility. 1,044 were eligible, interviewed and followed through their pregnancies. Classification and Regression Trees (CART) methodology was used to: (1) explore the relationship between medical and behavioral risks (reported at enrollment), sociodemographic factors and pregnancy outcomes; (2) identify the relative importance of various predictors of adverse pregnancy outcomes; and (3) characterize women at the highest risk of poor pregnancy outcomes. The strongest predictors of poor outcomes were prepregnancy BMI, preconceptional diabetes, employment status, intimate partner violence, and depression. In CART analysis, preeclampsia was the first splitter for low birthweight; preconceptional diabetes was the first splitter for preterm birth (PTB) and neonatal intensive care admission; BMI was the first splitter for very PTB, large for gestational age, Cesarean section and perinatal death; employment was the first splitter for miscarriage. Preconceptional factors strongly influence pregnancy outcomes. For many of these women, the high risks they brought into pregnancy were more likely to impact their pregnancy outcomes than events during pregnancy.  相似文献   
63.

Background  

This double-blind, randomized, controlled trial investigated the effect of the phosphodiesterase-5 inhibitor tadalafil on the microcirculation in patients with cold Complex Regional Pain Syndrome (CRPS) in one lower extremity.  相似文献   
64.
Magnetic resonance (MR) imaging was performed on 14 patients with histologically proved osteosarcoma (mean age, 14.4 years). There was excellent correlation of intramedullary tumor extent as determined with MR imaging and pathologic examination (r = 99%). This was facilitated by the presence of a chemical shift artifact at the tumor-marrow interface on the T1-weighted images. The correlation between CT and pathologic findings was not as good (r = 84%). In a single patient, however, a 10-cm length of sclerotic bone was incorrectly interpreted as being tumor. If this case is excluded, the correlation between CT and pathologic findings improves significantly (r = 96%). T2-weighted images were optimal in demonstrating soft-tissue bulk and breach of the epiphysis or cortex. Vascular involvement was also readily defined. The T2 value of the tumor soft-tissue component decreased in patients who were deemed to have responded well to therapy. Two patients with very high T2 values after chemotherapy developed wide-spread metastatic disease and died. Phosphorus-31 MR spectroscopy of five patients with osteosarcoma showed elevated levels of phosphomonoesters (PMEs), inorganic phosphate (Pi), and phosphodiesters (PDEs). PME and PDE peak areas decreased in three patients after chemotherapy, while Pi peak areas increased.  相似文献   
65.
Treatment of patients with chronic fatigue syndrome   总被引:2,自引:0,他引:2  
N M Gantz  G P Holmes 《Drugs》1989,38(6):855-862
  相似文献   
66.
Human blood groups: incidental receptors for viruses and bacteria   总被引:2,自引:0,他引:2  
  相似文献   
67.
福建省高校贫困大学生心理健康水平与人格特征   总被引:1,自引:0,他引:1  
目的:了解贫困生的心理健康现状和人格特征。方法:于2005-09/11随机抽取福州大学、福建师范大学、福建农林大学、福建中医学院、闽江学院2002-2004级学生2400名。男1478名,女922名,平均(20±1)岁。根据2004-11-04福建省福州市政府办公厅正式下发的《福州市人民政府关于提高城区城镇及农村居民最低生活保障标准的通知》中的规定,即城镇多人户每人每个月210元、单人户230元;农村多人户每人每月155元、单人户175元,本文把家庭人均月收入较少,有一定数额债务,只能缴纳部分学杂费,基本生活费接近于当地居民最低生活保障线(如上规定,本文以230元为基准)的学生定为“贫困生”。采用精神症状自评量表和16种人格因素问卷对高校贫困生的心理健康和人格特征进行调查。结果:发放问卷2400份,收回有效问卷2111份。其中贫困生539份。①贫困生精神症状自评量表的躯体化、强迫、人际敏感、抑郁、焦虑、敌对、恐怖、偏执、精神病性、其他、总症状指数得分均高于非贫困生(贫困生:1.61±0.56,2.02±0.64,1.92±0.63,1.71±0.56,1.65±0.58,1.73±0.68,1.57±0.62,1.81±0.65,1.67±0.54,1.76±0.63,1.74±0.49;非贫困生:1.48±0.45,1.89±0.56,1.79±0.57,1.61±0.51,1.54±0.50,1.61±0.56,1.44±0.49,1.66±0.54,1.54±0.46,1.61±0.53,1.62±0.41,P<0.01)。男女贫困生之间各因子分差异均不显著(P>0.05)。②福建省高校贫困大学生的心理问题检出率为24.5%,其中轻度心理问题(2≤因子分<3)为22.6%;中度心理问题(3≤因子分<4)为1.7%;重度心理问题(4≤因子分<5)为0.2%。心理问题以强迫、人际敏感、偏执、忧郁、敌对、焦虑等心理问题最为突出。③16种人格因素问卷中,贫困生乐群性、聪慧性、兴奋性、敏感性、怀疑性上得分低于非贫困生,有恒性、忧虑性、独立性得分高于非贫困生(贫困生:5.20±1.77,4.70±1.93,5.49±1.87,6.46±1.79,4.29±1.71,4.60±1.63,6.64±1.82,5.07±1.82;非贫困生:5.39±1.74,4.95±1.99,5.82±1.91,6.66±1.75,4.55±1.77,4.36±1.69,6.43±1.94,4.89±1.77,P<0.05~0.01)。④影响贫困生心理健康水平的主要人格因素按其影响作用从大到小有怀疑性、忧虑性、稳定性、兴奋性、自律性。结论:福建省高校贫困大学生的心理健康状况令人担忧,其人格特征对心理健康水平有重要影响。  相似文献   
68.

Background

The functions of synthetic bone graft substitutes include not only structural support to provide bone healing and osseous ingrowth but also the ability to serve as a local antibiotic delivery system to prevent or treat infections of the spine.

Material and Methods

The impregnation and antibiotic efficiency of gentamicin and levofloxacin with Healos was investigated in vitro and compared with Healos without an antibiotic additive. These antibiotic-loaded bone graft substitutes were examined without dilution and with 10-fold and 100-fold dilution for activity against spondylodiscitis-causing bacteria on different agar plates using an agar diffusion method.

Results

All hydroxyapatite (HA)/collagen-saturated diluted antibiotics showed elliptical inhibition zones on the corresponding agar plates. For both antibiotics, there was a linear correlation between dilution and area of the inhibition zone.

Conclusion

The analysis showed that the antimicrobial activity of HA/collagen-saturated antibiotics corresponded to the antimicrobial dilutions. These results should be further analyzed using in vivo studies to determine the remaining antibiotic efficiency after implantation of bone graft substitutes.  相似文献   
69.

Purpose

The inter-session repeatability (ISR), inter-examiner reproducibility (IER) and within-subject variability (WSV) of the Cobra HD fundus camera meibographer were examined in participants with and without dry eye symptoms.

Methods

Symptoms were determined based on Ocular Surface Disease Index scores (≥13 being considered symptomatic), and subgroups were compared using the Mann–Whitney U-test. Images of meibomian glands (MGs) from the upper and lower right eyelids were captured by two examiners on the same day (S1) to determine IER. One examiner repeated the measurements on a second day (S2) to obtain the ISR. ISR, IER and WSV were calculated using Friedman, correlation tests and Bland and Altman analyses with mean differences (md) and 95% confidence intervals (CIs), within-subject standard deviations (Sw) and intra-class correlation coefficients (ICC).

Results

The ISR experiment included 72 participants (mean age: 23 ± 5 years, range: 19–43, 36 symptomatic). Mean MG loss of the upper (S1: 13.5 ± 9.5%, S2: 12.8 ± 8.5%) and lower eyelids (S1: 7.5 ± 6.9%, S2: 7.3 ± 6.3%) was not significantly different between sessions for all participants, symptomatic and asymptomatic subgroups for both eyelids. The ISR Sw for the upper and lower eyelids was 1.3% and 1.0%; md was 0.7 ± 3.5% (CI:−6.25% to 7.62%) and 0.1 ± 2.1% (CI: −3.94% to 4.17%), respectively. The IER experiment included 74 participants (mean age: 23 ± 5 years, range: 19–43, 37 symptomatic). Mean MG loss of the upper (Examiner 1: 12.7 ± 8.2%, Examiner 2: 13.1 ± 8.0%) and lower eyelids (Examiner 1: 7.0 ± 6.2%, Examiner 2: 7.4 ± 6.2%) was not significantly different between examiners for all participants, symptomatic and asymptomatic subgroups for both eyelids. The IER ICC values were >0.86 for all conditions, Sw was 1.3% and 1.2%, with a md of −0.4 ± 3.2% (CI: −6.65% to 5.90%) and −0.4 ± 2.9% (CI: −6.15% to 5.31%), respectively. The WSV Sw values were <1.4%, and ICC values were >0.89 for both eyelids, examiners and experimental sessions.

Conclusions

The Cobra HD fundus camera demonstrates good repeatability, reproducibility and low WSV, and is a reliable clinical instrument for meibography.  相似文献   
70.
Strand L, Jenkins A, Grude N, Allum A‐G, Mykland H‐C, Nowrouzian FL, Kristiansen B‐E. Emergence of fluoroquinolone‐resistant clonal group A: clonal analysis of Norwegian and Russian E. coli isolates. APMIS 2010; 118: 571–77. We describe a study of urinary tract and intestinal isolates of Escherichia coli from Norway and Russia using automated ribotyping, single nucleotide polymorphism analysis for clonal group A (CgA) supplemented with phylogrouping, virulence gene profiling and resistance profiling. CgA comprised 19% of the Norwegian UTI isolates from 2001. Two highly multiresistant fluoroquinolone‐resistant CgA isolates were found. Ribotypes clustered into four major and six minor groups (ribogroups). Fluoroquinolone‐resistant isolates and phylogroups A and B1 were associated with ribogroup RA. Ribogroup RB predominated among Russian UTI isolates and was predominantly phylogroup A and depleted in P‐fimbriae. Ribogroup RC predominated among Norwegian UTI isolates and was rich in virulence factors (S‐fimbriae, haemagglutinin and haemolysin) and predominantly phylogroup B2 and D. Ribogroup RG was associated with CgA and predominantly phylogroup D. Ribogroups RD, RE and RF had too few members for statistical analysis. The correlation between ribotype and phylogenetic group was not as strong as reported in other studies.  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