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   925篇
  免费   75篇
  国内免费   6篇
耳鼻咽喉   1篇
儿科学   46篇
妇产科学   26篇
基础医学   104篇
口腔科学   30篇
临床医学   76篇
内科学   160篇
皮肤病学   22篇
神经病学   53篇
特种医学   11篇
外国民族医学   1篇
外科学   103篇
综合类   16篇
预防医学   126篇
眼科学   67篇
药学   78篇
中国医学   21篇
肿瘤学   65篇
  2024年   5篇
  2023年   18篇
  2022年   31篇
  2021年   46篇
  2020年   25篇
  2019年   23篇
  2018年   37篇
  2017年   36篇
  2016年   29篇
  2015年   43篇
  2014年   52篇
  2013年   70篇
  2012年   68篇
  2011年   68篇
  2010年   52篇
  2009年   30篇
  2008年   58篇
  2007年   48篇
  2006年   52篇
  2005年   45篇
  2004年   47篇
  2003年   37篇
  2002年   31篇
  2001年   6篇
  2000年   3篇
  1999年   6篇
  1998年   10篇
  1997年   3篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1990年   4篇
  1989年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1974年   1篇
  1973年   1篇
  1970年   1篇
排序方式: 共有1006条查询结果,搜索用时 31 毫秒
11.
12.
Objective: To evaluate the efficacy of preoperative vaginal cleansing using chlorhexidine 0.25% antiseptic wipes on rates of postcesarean section (CS) infectious morbidities (endometritis, febrile morbidity and wound infection).

Methods: This prospective randomized trial was conducted among 218 pregnant women scheduled for term elective CS. Patients were equally divided into two groups by simple randomization. After spinal anesthesia and catheterization under aseptic technique, the study group had preoperative vaginal cleansing using chlorhexidine 0.25% antiseptic wipes for about 1?min, while the control group did not. All cases received the prophylactic antibiotics and the usual abdominal scrub. All participants received the routine postoperative care without other interventions. Adverse postcesarean infectious morbidities such as endometritis, febrile morbidity and wound infection were observed at the time of hospital discharge and weekly for 6 weeks postpartum.

Results: Both groups were matched regarding the baseline patients’ characteristics (age, gestational age, BMI, operative time and postoperative hospital stay). Overall, post-CS infectious morbidity were significantly reduced from 24.4% in the control group to 8.8% in the intervention group; p value?<0.05. Marked reduction was seen in the incidence of endometritis (13.2% in the control group versus 2.9% in the intervention group; p value?<0.05). However, fever and wound infection showed no significant difference between both groups.

Conclusion: Cleansing the birth canal with chlorhexidine 0.25% wipes prior to elective CS appears to be effective in reducing rates of post-CS infectious morbidity mainly endometritis.  相似文献   
13.
14.
Background: Inorganic arsenic is one of the most common naturally occurring contaminants found in the environment. Arsenic is associated with a number of health outcomes, with epigenetic modification suggested as a potential mechanism of toxicity.Objective: Among a sample of 400 adult participants, we evaluated the association between arsenic exposure, as measured by blood and urinary total arsenic concentrations, and epigenome-wide white blood cell DNA methylation.Methods: We used linear regression models to examine the associations between arsenic exposure and methylation at each CpG site, adjusted for sex, age, and batch. Differentially methylated loci were subsequently examined in relation to corresponding gene expression for functional evidence of gene regulation.Results: In adjusted analyses, we observed four differentially methylated CpG sites with urinary total arsenic concentration and three differentially methylated CpG sites with blood arsenic concentration, based on the Bonferroni-corrected significance threshold of p < 1 × 10–7. Methylation of PLA2G2C (probe cg04605617) was the most significantly associated locus in relation to both urinary (p = 3.40 × 10–11) and blood arsenic concentrations (p = 1.48 × 10–11). Three additional novel methylation loci—SQSTM1 (cg01225779), SLC4A4 (cg06121226), and IGH (cg13651690)—were also significantly associated with arsenic exposure. Further, there was evidence of methylation-related gene regulation based on gene expression for a subset of differentially methylated loci.Conclusions: We observed significant associations between arsenic exposure and gene-specific differential white blood cell DNA methylation, suggesting that epigenetic modifications may be an important pathway underlying arsenic toxicity. The specific differentially methylated loci identified may inform potential pathways for future interventions.Citation: Argos M, Chen L, Jasmine F, Tong L, Pierce BL, Roy S, Paul-Brutus R, Gamble MV, Harper KN, Parvez F, Rahman M, Rakibuz-Zaman M, Slavkovich V, Baron JA, Graziano JH, Kibriya MG, Ahsan H. 2015. Gene-specific differential DNA methylation and chronic arsenic exposure in an epigenome-wide association study of adults in Bangladesh. Environ Health Perspect 123:64–71; http://dx.doi.org/10.1289/ehp.1307884  相似文献   
15.
Glanzmann thrombasthenia (GT) is an autosomal recessive platelet function disorder characterized by mucocutaneous bleeding as the most common clinical phenotype. Patients with GT have normal platelet counts, platelet morphology but reduced platelet aggregation in response to various agonists. Homozygosity or compound heterozygosity for variants in the ITGA2B/ITGB3 genes is the genetic basis for GT. Establishing a molecular diagnosis is definitive and is important for predictive testing. Using multi-gene panels is an accurate, faster, and cost-effective mode as compared to Sanger sequencing in large genes. We used a targeted resequencing based approach to identify pathogenic variants in eight cases in seven families. These variants were validated using Sanger sequencing in patients as well as family members and were predicted probably pathogenic using in-silico prediction tools. The variants include three missense (3/7 = 43%) (ITGA2B:c.1028 T > C, ITGA2B:c.1186G > A, ITGB3:c.1388G > C), two deletions (ITGA2B:c.559delG, ITGA2B:c.3092delT), one duplication (ITGA2B:c.1424_1427dupAGGT) and nonsense variant (ITGA2B:c.2578C > T, p.Gln860Ter). Except for one case which was compound heterozygous, the rest of the cases were homozygous. We found two novel variants that are reported for the first time in GT. The targeted resequencing based approach revealed varied genetic variants in North Indian patients, including two novels ones. The high yield of our panel indicates its suitability for usage in larger cohorts for the genetic diagnosis of GT patients. This approach is cost-effective and less cumbersome as compared to Sanger sequencing for these large size genes with multiple exons. The information so obtained is helpful in prenatal testing, carrier analysis, and genetic counseling.  相似文献   
16.
BackgroundHighly crosslinked ultra-high molecular weight polyethylene (UHMWPE) has shown success in reducing wear in hip arthroplasty but there remains skepticism about its use in Total Knee Replacement (TKR) inserts that are known to experience fatigue loading and higher local cyclic contact stresses.MethodsTwo Legacy Posterior-Stabilized (LPS) Zimmer NexGen tibial implants sterilized by gamma irradiation in an inert environment with posts that fractured in vivo were analyzed. Failure mechanisms were determined using optical and scanning electron microscopy along with oxidative analysis via Fourier Transform Infra-Red (FTIR) spectroscopy.ResultsMicrographs of one retrieval revealed fatigue crack initiation on opposite sides of the post and quasi-brittle micromechanisms of crack propagation. FTIR of this retrieval revealed no oxidation. The fracture surface image of the second retrieval indicated a brittle fracture process and FTIR revealed oxidation in the explant.ConclusionsThese two cases suggest that crosslinking of UHMWPE as a manufacturing process or sterilization method in conjunction with designs that incorporate high stress concentrations, such as the tibial post, may reduce material strength. Moreover, free radicals generated from ionizing radiation can render the polymer susceptible to oxidative embrittlement.Clinical relevanceOur findings suggest that tibial post fractures may be the results of in vivo oxidation and low level crosslinking. These and previous reports of fractured crosslinked UHMWPE devices implores caution when used with high stress concentrations, particularly when considering the potential for in vivo oxidation in TKR.  相似文献   
17.
Objectives: To investigate what the most common types of articles that nursing journals purport to publish are and what they actually publish. And to investigate the extent to which academic nursing journals listed by Clarivate track alternative metrics.Methods: Journals included in the nursing Journal Citation Report (JCR) journal category in 2019 described as nursing were identified and considered suitable for inclusion in the analysis. Instructions for authors were reviewed online and mention of each type of article is identified. The tables of contents of each issue of each journal published during 2019 were examined and the types of articles published were extracted to a spreadsheet into permitted article types and published articles. Likewise, the use of alternative metrics by each journal was extracted to a spreadsheet. Pearson's and Spearman's correlation analysis was applied to investigate the relationship between articles permitted and articles published.Results: In the 2020 JCR, 123 journals were listed. The most common article type permitted was original research (n = 117),followed by review papers (n = 116), and discussion papers (n = 63). Original research (n = 7045); review papers (n = 1268);discussion papers (n = 1225); editorials (n = 793) and commentaries (n = 776) were the most commonly published categories of the article. Of journals examined, 108 (96.8%) tracked mentions on social media and the Altmetric score was most commonly used (75%). There was a strong correlation (r = 0.73; P = 0.002) between the numbers of articles permitted and published and a strong correlation (ρ = 0.86; P < 0.001) in terms of the rankings of the permitted and published articles.Conclusions: There is a relationship between the most frequently permitted article types and those published, especially for the most frequent categories of both. Original articles, review papers, and discussion papers are the backbone of academic publishing in nursing with original articles vastly outweighing review and discussion papers. Most Clarivate listed journals now use some method of tracking alternative metrics indicating how seriously publishers take their social media profiles.  相似文献   
18.
19.
A double-lumen perfusion technique has been used to study amino acid and peptide absorption in eight normal control subjects, 13 patients with untreated adult coeliac disease, and 16 patients with dermatitis herpetiformis who had varying morphological abnormalities of the small bowel. All subjects were perfused with isotonic solutions containing 10 mM glycyl-L-alanine and 10 mM glycine + 10 mM L-alanine.Patients with adult coeliac disease had impaired absorption of glycine (p < 0.01) and L-alanine (p < 0.05) from the amino acid solution compared with the control subjects. Amino acid uptake from the dipeptide solution was not significantly impaired, although four individual patients had impaired uptake of both amino acids. In contrast to these findings, very few patients with dermatitis herpetiformis had impaired amino acid absorption from either solution.Sodium absorption was impaired from both solutions when the groups of patients with adult coeliac disease and dermatitis herpetiformis with subtotal villous atrophy and partial villous atrophy were studied, and there were patients in each group who secreted sodium and water.The results suggest that malabsorption of dietary protein is unlikely to occur in dermatitis herpetiformis but may occur and contribute to protein deficiency seen in some severe cases of adult coeliac disease. The impairment of sodium and water absorption provides evidence that there may be functional impairment of the jejunal mucosa in dermatitis herpetiformis as well as in adult coeliac disease.  相似文献   
20.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - In vitro antioxidant potential of methanolic extract of saffron and crocetin was assessed along with...  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