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   929篇
  免费   67篇
  国内免费   18篇
耳鼻咽喉   2篇
儿科学   24篇
妇产科学   14篇
基础医学   87篇
口腔科学   8篇
临床医学   46篇
内科学   143篇
皮肤病学   8篇
神经病学   25篇
特种医学   138篇
外科学   106篇
综合类   51篇
预防医学   59篇
眼科学   205篇
药学   36篇
  1篇
肿瘤学   61篇
  2023年   3篇
  2022年   10篇
  2021年   31篇
  2020年   12篇
  2019年   21篇
  2018年   30篇
  2017年   17篇
  2016年   23篇
  2015年   27篇
  2014年   28篇
  2013年   30篇
  2012年   53篇
  2011年   56篇
  2010年   25篇
  2009年   35篇
  2008年   75篇
  2007年   62篇
  2006年   40篇
  2005年   39篇
  2004年   39篇
  2003年   29篇
  2002年   32篇
  2001年   40篇
  2000年   46篇
  1999年   19篇
  1998年   19篇
  1997年   11篇
  1996年   7篇
  1995年   5篇
  1994年   7篇
  1993年   10篇
  1992年   10篇
  1991年   5篇
  1990年   6篇
  1989年   10篇
  1988年   13篇
  1987年   15篇
  1986年   17篇
  1985年   10篇
  1984年   2篇
  1983年   4篇
  1981年   3篇
  1980年   7篇
  1979年   7篇
  1978年   4篇
  1977年   3篇
  1976年   2篇
  1975年   5篇
  1974年   4篇
  1973年   3篇
排序方式: 共有1014条查询结果,搜索用时 15 毫秒
91.
A cross-sectional study of 432 army college students comprising 278 medical cadets and 154 nursing students, ages ranging from 15 to 26 years, was conducted in 2001 to determine the seroprevalence of hepatitis A virus (HAV) antibody. Serum specimens were tested for HAV antibody by a commercial enzyme immunoassay method. Anti-HAV was detected in 14.0%, 17.5%, and 15.3% of medical cadets, nursing students, and the total cohort, respectively. There was no statistically significant difference in seroprevalence between medical cadets and nursing students. Increasing prevalence of HAV correlated with increasing age. Significantly higher seroprevalence was detected in students from provinces outside of Bangkok compared to those who were from Bangkok (18.7% vs. 9.8%). The highest HAV seroprevalence was observed in subjects from the northeastern region of Thailand, suggesting that this region may be associated with greater risk for infection and should be the focus of preventive health strategies.  相似文献   
92.
Limited microbiology services impede adequate diagnosis and treatment of common infections such as pyelonephritis in resource-limited settings. Febrile pregnant women attending antenatal clinics at Shoklo Malaria Research Unit were offered urine dipstick, sediment microscopy, urine culture, and a 5-mL blood culture. The incidence of pyelonephritis was 11/1,000 deliveries (N = 53 in 4,819 pregnancies) between January 7, 2004 and May 17, 2006. Pyelonephritis accounted for 20.2% (41/203) of fever cases in pregnancy. Escherichia coli was the most commonly isolated pathogen: 87.5% (28/32) of organisms cultured. Susceptibility of E. coli to ampicillin (14%), cotrimoxazole (21%), and amoxicillin-clavulanic acid (48%) was very low. E. coli was susceptible to ceftriaxone and ciprofloxacin. The rate of extended spectrum β-lactamase (4.2%; 95% confidence interval = 0.7-19.5) was low. The rate and causes of pyelonephritis in pregnant refugee and migrant women were comparable with those described in developed countries. Diagnostic innovation in microbiology that permits affordable access is a high priority for resource-poor settings.  相似文献   
93.
94.
Tan JT  Dorajoo R  Seielstad M  Sim XL  Ong RT  Chia KS  Wong TY  Saw SM  Chew SK  Aung T  Tai ES 《Diabetes》2008,57(10):2851-2857
OBJECTIVE— Association between genetic variants at the FTO locus and obesity has been consistently observed in populations of European ancestry and inconsistently in non-Europeans. The aim of this study was to examine the effects of FTO variants on obesity and type 2 diabetes in Southeast Asian populations.RESEARCH DESIGN AND METHODS— We examined associations between nine previously reported FTO single nucleotide polymorphisms (SNPs) with obesity, type 2 diabetes, and related traits in 4,298 participants (2,919 Chinese, 785 Malays, and 594 Asian Indians) from the 1998 Singapore National Health Survey (NHS98) and 2,996 Malays from the Singapore Malay Eye Study (SiMES).RESULTS— All nine SNPs exhibited strong linkage disequilibrium (r2 = 0.6–0.99), and minor alleles were associated with obesity in the same direction as previous studies with effect sizes ranging from 0.42 to 0.68 kg/m2 (P < 0.0001) in NHS98 Chinese, 0.65 to 0.91 kg/m2 (P < 0.02) in NHS98 Malays, and 0.52 to 0.64 kg/m2 (P < 0.0001) in SiMES Malays after adjustment for age, sex, smoking, alcohol consumption, and exercise. The variants were also associated with type 2 diabetes, though not after adjustment for BMI (with the exception of the SiMES Malays: odds ratio 1.17–1.22; P ≤ 0.026).CONCLUSIONS— FTO variants common among European populations are associated with obesity in ethnic Chinese and Malays in Singapore. Our data do not support the hypothesis that differences in allele frequency or genetic architecture underlie the lack of association observed in some populations of Asian ancestry. Examination of gene-environment interactions involving variants at this locus may provide further insights into the role of FTO in the pathogenesis of human obesity and diabetes.A recent genome-wide association study for type 2 diabetes using a U.K.-based population revealed a novel locus associated with BMI: the fat mass–and obesity-related gene (FTO) on chromosome 16 (1). The representative single-nucleotide polymorphism (SNP), rs9939609, was confirmed to be associated with elevated BMI after replication in more than 38,000 study participants of European ancestry. Further replication of this association has been observed in several populations of distinctly European ancestry (26). However, this association is inconsistent in populations of non-European ancestry. A study in Japanese showed an association between variants at this locus and obesity (7) that was not observed in African Americans (6) or Han Chinese (8). The aims of this study were 1) to determine the associations between previously identified obesity-associated SNPs at the FTO locus with obesity and type 2 diabetes in Chinese, Malays, and Asian-Indians and 2) to examine whether any associations were modulated by exercise.  相似文献   
95.
Photodynamic diagnosis (PDD) using hypericin (HY), a natural photosensitizer, detects bladder cancer significantly better than white light endoscopy. However, the lipophilicity of HY complicates its administration for clinical applications. Currently, pharmaceutical preparations for HY without plasma protein are being developed. Formulations containing a biocompatible solvent, N-methyl pyrrolidone (NMP) have been shown to enhance the photodynamic therapeutic effects of HY. It was recently reported that, NMP formulations of HY were able to produce significantly higher contrast for fluorescence detection of tumors than albumin-containing HY formulations. This present work hypothesizes that NMP acts both as a solvent and penetration enhancer to improve the delivery of HY into cells by increasing the permeability of cell membranes. This paper reports the use of 3-D confocal microscopy to monitor real-time uptake of HY in human carcinoma. 3-D confocal microscopy was used to investigate the possibility of nuclear localization of HY in MGH cells. The fluorescence of HY was confirmed to be emitted from HY containing cells using spectrometry. The localization of a DNA fluorescent probe 4', 6-diamidino-2-phenylindole dihydrochloride (DAPI) was used to confirm the possibility of colocalization of DAPI and HY. The colocalization analysis in the present study suggests that it was very unlikely that HY colocalized in the nucleus that was stained by DAPI. Fluorescein leakage tests showed that 1% NMP changes the permeability of cell membranes, and enhanced the delivery of HY into cells resulting in lower cell survival ratios. Thus, NMP was able to enhance the photodynamic therapeutic effects of HY on cancer cells.  相似文献   
96.
97.
BACKGROUND: Traditional approaches to Javal's rule do not use data from subjects with oblique astigmatism and have not been used to make predictions about subjects with oblique astigmatism. Vector approaches to analyzing refractive error can circumvent these problems. METHODS: Subjects were 993 Singaporean schoolchildren. We performed linear regression of refractive error astigmatism on corneal astigmatism, using J0 vectors to describe with-the-rule and against-the-rule astigmatism and J45 vectors to describe oblique astigmatism. RESULTS: We obtained the following statistically significant regression relationships: RJ0 = 0.931 x CJ0 - 0.276 and RJ45 = 0.638 x CJ45 + 0.010, where R and C denote refractive error astigmatism and corneal astigmatism, respectively. CONCLUSION: Our vector-based Javal's rule gives closer predictions of refractive astigmatism than the original Javal's rule and the simplified Javal's rule and can be applied in cases of corneal oblique astigmatism.  相似文献   
98.
《中华男科学》杂志2000~2002年载文及引文分析   总被引:15,自引:2,他引:13  
目的 :评价《中华男科学》杂志的地位和社会影响力。 方法 :用文献计量学方法对 2 0 0 0~ 2 0 0 2年《中华男科学》杂志载文及其引文情况进行统计分析。 结果 :除综述性文献和译文外 ,3年 16期共载文 34 3篇 ,其中333篇文献有引文 ,占载文总数的 97.0 8%;论著共计 183篇 ,占 5 3.35 %;基金项目论文 6 2篇 ,占总载文量的18.0 8%;载文量与基金项目论文篇数逐年增加 ;分布在全国 30个省及直辖市 ,作者中 43.37%为高级职称 ,拥有博士、硕士学位的占 40 .80 %;期刊与作者平均自引率为 6 .30 %、3.39%;文献发表 5年内被引用的频率最高 ,普赖斯指数为 5 6 .0 3%;引文语种以英文文献为主 ,期刊占引文总数的 83.0 2 %。 结论 :该刊拥有一批优秀的作者群体 ,具有很强的社会影响力以及广阔的发展前景 ,是一高质量的学术期刊。  相似文献   
99.
100.
慢性骨盆疼痛综合征前列腺液16S rRNA基因检测及临床意义   总被引:3,自引:1,他引:2  
周立权  沈明  赵岩 《中华男科学杂志》2003,9(4):263-265,269
目的 :通过前列腺液 16SrRNA基因的检测 ,探讨慢性骨盆疼痛综合征 (CPPS)的细菌感染性病因及其对抗生素疗效的预测价值。 方法 :用通用引物PCR法检测 5 9例CPPS病人前列腺液 (EPS)和初段尿 (VB1)细菌16SrRNA基因。若只在EPS检测到条带 ,或EPS信号比VB1强 10倍以上 ,则细菌信号判断为阳性。所有病人口服左氧氟沙星及阿奇霉素治疗 4周。与治疗前相比 ,治疗后症状严重性积分指数 (SSI)、症状频度问卷积分 (SFQ)、前列腺炎症状积分指数 (NIH CPSI)中疼痛问题的总积分 (quasi CPSI)减少 5 0 %以上 ,或病人主观总体评价改善5 0 %以上作为治疗有效的标准。 结果 :5 9例CPPS病人中细菌信号阳性 46例、阴性 13例。细菌信号阳性与阴性两组治疗有效率分别为 6 5 %~ 74%、0 ,疗效差异有极显著性 (P <0 .0 1)。 结论 :部分CPPS与细菌感染有关 ,前列腺 16SrRNA基因检测的结果对选择抗生素治疗有指导意义。  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