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   598篇
  免费   25篇
  国内免费   4篇
耳鼻咽喉   20篇
儿科学   32篇
妇产科学   31篇
基础医学   92篇
口腔科学   2篇
临床医学   35篇
内科学   148篇
皮肤病学   9篇
神经病学   38篇
特种医学   14篇
外科学   44篇
综合类   8篇
预防医学   54篇
眼科学   5篇
药学   66篇
中国医学   1篇
肿瘤学   28篇
  2023年   5篇
  2022年   35篇
  2021年   38篇
  2020年   15篇
  2019年   18篇
  2018年   24篇
  2017年   11篇
  2016年   20篇
  2015年   18篇
  2014年   32篇
  2013年   38篇
  2012年   61篇
  2011年   53篇
  2010年   21篇
  2009年   17篇
  2008年   30篇
  2007年   55篇
  2006年   31篇
  2005年   32篇
  2004年   28篇
  2003年   16篇
  2002年   20篇
  2001年   2篇
  2000年   2篇
  1997年   2篇
  1994年   1篇
  1985年   1篇
  1979年   1篇
排序方式: 共有627条查询结果,搜索用时 15 毫秒
81.
A rise in the incidence of infections with severe acute respiratory syndrome coronavirus 2 has sparked the search for protective strategies against the new pathogen. It is known that individual food components can interact with different immune cells, modulating the immune response of the body. The aim of this study was to develop an index assessing the immunomodulatory potential of diet (POLA index) and to test its utility for the prediction of coronavirus disease 2019 (COVID-19) in a group of healthy young people following a traditional or vegetarian diet. Data on body composition, anthropometric measurements, physical activity, dietary intake, and gut microbiota were obtained from 95 adults (mean age, 34.66 ± 5.76 years). There was a strong correlation between the dietary inflammatory index and the POLA index (r = 0.90; p < 0.0001). Based on Cohen’s kappa statistic, there was a good agreement in qualitative interpretation between the two indices (kappa = 0.61; p < 0.0001). People on a diet with beneficial immunomodulatory effects had a lower risk of COVID-19 of approximately 80%, as compared with those on a diet with highly unbeneficial immunomodulatory effects. In daily practice, the POLA index might serve as a useful tool for dietitians to identify individuals whose diet is deficient in ingredients for optimal immune system function and change their dietary behavior to ensure optimal immune function that reduces the risk of infection.  相似文献   
82.
The relationship of high-carbohydrate (HC) meal intake to metabolic syndrome is still not fully explained. Metabolomics has the potential to indicate metabolic pathways altered by HC meals, which may improve our knowledge regarding the mechanisms by which HC meals may contribute to metabolic syndrome development. The fasting and postprandial metabolic response to HC or normo-carbohydrate (NC) meals with/without cinnamon + capsicum intake was evaluated using untargeted metabolomics and compared between normal-weight (NW) and overweight/obese (OW/OB) healthy men. Healthy male participants (age-matched) were divided into two groups (12 subjects per group). One was composed of men with normal weight (NW) and the other of men with overweight/obesity (OW/OB). On separate visits (with 2–3 week intervals), the participants received standardized HC or NC meals (89% or 45% carbohydrates, respectively). Fasting (0 min) and postprandial (30, 60, 120, 180 min) blood were collected for untargeted plasma metabolomics. Based on each metabolic feature’s intensity change in time, the area under the curve (AUC) was calculated. Obtained AUCs were analyzed using multivariate statistics. Several metabolic pathways were found dysregulated after an HC meal in people from the OW/OB group but not the NW group. The consumption of HC meals by people with overweight/obesity led to a substantial increase in AUC, mainly for metabolites belonging to phospholipids and fatty acid amides. The opposite was observed for selected sphingolipids. The intake of cinnamon and capsicum normalized the concentration of selected altered metabolites induced by the intake of HC meals. A HC meal may induce an unfavourable postprandial metabolic response in individuals with overweight/obesity, and such persons should avoid HC meals.  相似文献   
83.
Purpose. The aim of this study was to assess the reproducibility and reliability of the KomPAN questionnaire among two groups of university students from Germany and Slovakia. Methods. A total of 422 individuals (mean age 21.4 years, SD 4.0), including 197 from Slovakia (men 26.2%) and 225 from Germany (men 22.3%), were tested using the self-administered (SA-Q) version of the KomPAN questionnaire and then retested two weeks later. A cross-classification analysis, kappa coefficients, Cronbach’s ɑ coefficients, and a test-retest result comparison were conducted separately for each group of students to assess the reproducibility and reliability of the questionnaire. Results. The cross-classification values were higher than 46.2% among the German students and higher than 55.8% among the Slovakian students. The kappa coefficients ranged from 0.21 to 0.90 in the German students and from 0.38 to 0.94 in the Slovakian students. Cronbach’s ɑ ranged from 0.58 to 0.78. Conclusion. The questionnaire displayed a moderate to very good reproducibility, which was slightly higher in the Slovakian group than in the German group. Therefore, the questionnaire can be recommended for further analysis and comparison of the dietary habits among Germans and Slovakians on a larger scale.  相似文献   
84.
Sonoelastography is a novel technique, useful in a noninvasive assessment of lesions in multiple organs. The aim of the study was to examine whether the combination of conventional ultrasonography (US) with sonoelastography might improve the reliability of parotid tumor evaluation. Fourty-three consecutive patients with parotid tumors were surgically treated at a single tertiary center at the Department of Otolaryngology, Head and Neck Surgery. The sample included 27 women and 16 men, aged 15–80 (the mean age = 54 years). The reference group constituted of 54 healthy volunteers. High resolution grayscale ultrasonography (US) was performed preoperatively using a 15 MHz linear array transducer. Elastograms (ES) were scored by the conventional Ueno 5-point scale from ES1 (blue-soft) to ES5 (the entire lesion and surrounding area shaded red-stiff). In addition, detailed stiffness values in kPa were collected. The group consisted of 33 patients with benign and 10 patients with malignant tumors. The mean stiffness value was 146.6 kPa in 10 malignant tumors (mostly ES4) and 88.7 kPa in 33 benign tumors (mostly ES2 and ES3). The differences in tissue stiffness between normal parotid parenchyma in the reference group and the mean value for all tumors in the examined group were statistically significant (p < 0.001), and so was the case with the differences between the benign and malignant tumors (p < 0.001). Low stiffness scores (ES1,2) were found in 2 malignant and 15 benign tumors while high scores (ES3,4) were found in 8 malignancies and 18 benign tumors. Sonoelastography overlapping elasticity to the grayscale images supports additional informations. Preferential selection of the lesions characterized by high stiffness (ES4) improves the differential diagnosis of parotid tumors but the large degree of uncertainty of this method should also be pointed out.  相似文献   
85.
The CD3ζ chain, a component of the T cell receptor (TCR)/CD3 complex, is considered to be a limiting factor in the assembly and transport of the TCR/CD3 complex to the cell surface and is crucial to receptor signaling function. Recent studies have demonstrated altered expression and function of this signal transduction molecule in T and natural killer cells in patients with chronic inflammatory/autoimmune diseases. In this review, current knowledge concerning the expression of CD3ζ chain as well as the mechanisms responsible for abnormal expression of this molecule in systemic lupus erythematosus, rheumatoid arthritis, and childhood idiopathic nephrotic syndrome are summarized.  相似文献   
86.
Cryptosporidium spp. infection is usually self-limited in immunocompetent hosts but can be severe and life threatening in children and in immunocompromised individuals including those with primary or acquired immunodeficiencies. One hundred and three faecal samples were collected from 35 hospitalised patients with different symptoms and tested for the presence of the parasite. Cryptosporidium oocysts were found in four of 35 patients (11.4%) using Ziehl–Neelsen staining of faecal smears and immunofluorescence assay, whereas 12 (34.3%) samples tested positive by nested polymerase chain reaction assay. Cryptosporidium DNA was detected in one bile sample but not in a liver tissue biopsy sample collected from a patient who suffered from sclerosing cholangitis. Sequence analysis of oocyst wall protein and beta-tubulin gene fragments revealed three different parasite species (Cryptosporidium hominis, Cryptosporidium meleagridis and Cryptosporidium parvum) in children with primary immunodeficiencies, whereas only C. parvum was found in immunocompetent individuals and in those with secondary immunodeficiencies. This study has revealed a high prevalence of Cryptosporidium infection in hospitalised patients in Poland and confirmed that molecular techniques enable a more sensitive detection of the parasite.  相似文献   
87.
The majority of low-grade squamous intraepithelial lesions (LSILs) of the cervix regress spontaneously; however, a small proportion of LSILs progress to high-grade squamous intraepithelial lesion (HSIL) if the lesion is not excised. The guidelines for which patients with LSIL should be treated and which may be followed safely are not well established. The goal of this study was to identify a subgroup of patients with LSIL who may require surgical treatment. We hypothesized that patients with LSILs with marked cytological atypia (LSIL-MA) may be at higher risk for subsequent HSIL. In addition, we were interested in whether LSIL-MA was associated with specific human papillomavirus genotypes. Consecutive patients with biopsy diagnosis of LSIL (n = 30) and LSIL-MA (n = 30) were identified. Marked atypia was defined as 5 or more cells with nuclear enlargement of at least 5 times the size of an intermediate cell nucleus or multinucleation with 5 or more nuclei. Patient follow-up was recorded for up to 24 months. Human papillomavirus genotyping was performed using SPF10 PCR and line probe assay. High-grade squamous intraepithelial lesion on follow-up was significantly more common in patients with LSIL-MA (36%) than in patients with LSIL (7%), and negative follow-up was significantly more common in patients with LSIL (50%) than LSIL-MA (23%). Cases of LSIL and LSIL-MA showed similar spectrum of human papillomavirus genotypes. Marked cytological atypia in LSILs identifies a subset of patients with a high rate of HSIL on follow-up. In such patients, an excisional cone biopsy should be strongly considered.  相似文献   
88.
By means of quantitative-biochemical and histomorphological methods after vagotomies changes of the liver could be proved to a smaller extent than after resections of the stomach (Billroth II). Among the bionomic operation methods the supra-selective proximal vagotomy without pylorplastics is superior to other methods under the aspect of the change of the liver.  相似文献   
89.
90.
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