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   5738篇
  免费   303篇
  国内免费   40篇
耳鼻咽喉   110篇
儿科学   202篇
妇产科学   118篇
基础医学   901篇
口腔科学   560篇
临床医学   401篇
内科学   1155篇
皮肤病学   144篇
神经病学   476篇
特种医学   108篇
外科学   458篇
综合类   25篇
一般理论   3篇
预防医学   551篇
眼科学   76篇
药学   421篇
中国医学   25篇
肿瘤学   347篇
  2024年   5篇
  2023年   50篇
  2022年   141篇
  2021年   238篇
  2020年   163篇
  2019年   194篇
  2018年   209篇
  2017年   130篇
  2016年   189篇
  2015年   230篇
  2014年   271篇
  2013年   345篇
  2012年   461篇
  2011年   536篇
  2010年   293篇
  2009年   248篇
  2008年   342篇
  2007年   367篇
  2006年   344篇
  2005年   316篇
  2004年   276篇
  2003年   210篇
  2002年   178篇
  2001年   36篇
  2000年   29篇
  1999年   39篇
  1998年   21篇
  1997年   28篇
  1996年   19篇
  1995年   13篇
  1994年   7篇
  1993年   17篇
  1992年   13篇
  1991年   12篇
  1990年   8篇
  1989年   11篇
  1988年   16篇
  1987年   8篇
  1986年   5篇
  1985年   11篇
  1984年   3篇
  1983年   14篇
  1981年   3篇
  1979年   3篇
  1977年   4篇
  1975年   4篇
  1973年   2篇
  1972年   3篇
  1971年   2篇
  1955年   2篇
排序方式: 共有6081条查询结果,搜索用时 15 毫秒
41.
British children have the highest levels of ultra-processed food (UPF) consumption in Europe. Schools are posited as a positive setting for impacting dietary intake, but the level of UPFs consumed in schools is currently unknown. This study determined the UPF content of school food in the UK. We conducted a pooled cross-sectional analysis of primary (4–11 years, n = 1895) and secondary schoolchildren (11–18 years, n = 1408) from the UK’s National Diet and Nutrition Survey (2008–2017). Multivariable quantile regression models determined the association between meal-type (school meal or packed lunch) and lunchtime UPF intake (NOVA food classification system). We showed that on average, UPF intake was high in both primary (72.6% total lunch Kcal) and secondary schoolchildren (77.8% total lunch Kcal). Higher UPF intakes were observed in packed lunch consumers, secondary schoolchildren, and those in lower income households. This study highlights the need for a renewed focus on school food. Better guidance and policies that consider levels of industrial processing in food served in schools are needed to ensure the dual benefit of encouraging school meal uptake and equitably improving children’s diets.  相似文献   
42.
Despite the rising evidence in favor of immunotherapy (IT), the treatment of oncological patients affected by so-called “cold tumors” still represents an open issue. Cold tumors are characterized by an immunosuppressive (so-called cold) tumor microenvironment (TME), which favors host immune system suppression, cancer immune-escape, and a worse response to IT. However, the TME is not a static element, but dynamically mutates and can be changed. Radiotherapy (RT) can modulate a cold microenvironment, rendering it better at tumor killing by priming the quiescent host immune system, with a consequent increase in immunotherapy response. The combination of TME radiomodulation and IT could therefore be a strategy for those patients affected by cold tumors, with limited or no response to IT. Thus, this review aims to provide an easy, rapid, and practical overview of how RT could convert the cold TME and why cold tumor radiomodulation could represent an interesting strategy in combination with IT.  相似文献   
43.
44.
45.
46.
The aim of this study was to evaluate the effects of N-acetylcysteine (NAC) on renal function, as well as on sodium and water transporters, in the kidneys of aged rats. Normal, 8-month-old male Wistar rats were treated (n = 6) or not (n = 6) with NAC (600 mg/L in drinking water) and followed for 16 months. At the end of the follow-up period, we determined inulin clearance, serum thiobarbituric acid reactive substances (TBARS), serum cholesterol, and urinary phosphate excretion. In addition, we performed immunohistochemical staining for p53 and for ED-1-positive cells (macrophages/monocytes), together with Western blotting of kidney tissue for NKCC2, aquaporin 2 (AQP2), urea transporter A1 (UT-A1) and Klotho protein. At baseline, the two groups were similar in terms of creatinine clearance, proteinuria, cholesterol, and TBARS. At the end of the follow-up period, NAC-treated rats presented greater inulin clearance and reduced proteinuria, as well as lower serum cholesterol, serum TBARS, and urinary phosphate excretion, in comparison with untreated rats. In addition, NAC-treated rats showed upregulated expression of NKCC2, AQP2, and UT-A1; elevated Klotho protein expression, low p53 expression, and few ED-1 positive cells. In conclusion, we attribute these beneficial effects of NAC (the significant improvements in inulin clearance and in the expression of NKCC2, AQP2, and UT-A1) to its ability to decrease oxidative stress, inhibit p53 expression, minimize kidney inflammation, and stimulate Klotho expression.  相似文献   
47.
The zoonotic potential to cause human and/or animal infections among multidrug-resistant extraintestinal pathogenic Escherichia coli from avian origin was investigated. Twenty-seven extraintestinal pathogenic E. coli isolates containing the increased survival gene (iss) were obtained from the livers of healthy and diseased poultry carcasses at two slaughterhouses in Salvador, northeastern Brazil. The antimicrobial resistance-susceptibility profiles were conducted with antibiotics of avian and/or human use by the standardized disc-diffusion method. Antimicrobial resistance was higher for levofloxacin (51.8%), amoxicillin/clavulanic acid (70.4%), ampicillin (81.5%), cefalotin (88.8%), tetracycline (100%) and streptomycin (100%). The minimum inhibitory concentrations above the resistance breakpoints of doxycycline, neomycin, oxytetracycline and enrofloxacin reached, respectively, 88.0%, 100%, 75% and 91.7% of the isolates. Strains with high and low antimicrobial resistance were i.p. administered to Swiss mice, and histopathological examination was carried out seven days after infection. Resistance to goat and human serum complement was also evaluated. The results show that Swiss mice challenged with strain 2B (resistant to 11 antimicrobials) provoked a severe degeneration of hepatocytes besides lymphocytic infiltration in the liver, whereas the spleen showed areas of degeneration of the white and red pulp. Conversely, the spleen and liver of mice challenged with strain 4A (resistant to two antimicrobials) were morphologically preserved. In addition, complement resistance to goat and human serum was high for strain 2B and low for strain 4A. Our data show that multidrug resistance and pathogenesis can be correlated in extraintestinal pathogenic E. coli strains obtained from apparently healthy poultry carcasses, increasing the risk for human public healthy.  相似文献   
48.
IntroductionChronic hepatitis C virus infection patients have higher rates of psychiatric disorders than the general population. Chronic hepatitis C virus infection is known to be associated with impaired health related quality of life. To our knowledge, there is no previous research of health related quality of life in chronic hepatitis C patients that combined structured psychiatric interview and careful psychopathological evaluation, including depression, anxiety and fatigue instruments. The aim of this study was to evaluate health related quality of life of chronic hepatitis C patients and to investigate the association with sociodemographic, psychopathological and psychiatric factors.Materials and methodsEighty-one individuals with chronic hepatitis C virus infection receiving care at a Brazilian public university-based outpatient service for infectious diseases were enrolled in the study. The World Health Organization Quality of Life Scale Brief Version was used to assess health related quality of life. Standard psychiatric interview (Mini International Neuropsychiatric Interview-Plus) was conducted to establish Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I psychiatric diagnosis. Further instruments completed psychopathological investigation: Beck Depression Inventory, Hospital Anxiety and Depression Scale, Brief Fatigue Inventory, Hamilton Depression Scale and Hamilton Anxiety Scale. Pearson Chi-Square and Kruskal–Wallis were performed for categorical and continuous univariate analysis, respectively. Correlation between psychopathological and health related quality of life scores was performed according to Spearman's correlation. Multivariate analysis was performed according to stepwise forward ordinal logistic regression. The significance threshold was fixed at α = 0.05.ResultsDepressive disorders were associated with worse scores in overall health related quality of life and in all domains. Fatigue was associated with lower scores in physical and psychological domains, and married status with higher scores in psychological health related quality of life. We found strong correlation among scores of depression, fatigue and health related quality of life.ConclusionDepression and fatigue must be properly investigated and managed in HCV patients in order to improve HRQL. WHOQOL-BREF proved to be a useful instrument to assess HRQL in HCV patients.  相似文献   
49.
Rhodotorula species are emergent fungal pathogens capable of causing invasive infections, primarily fungemia. They are particularly problematic in immunosuppressed patients when using a central venous catheter. In this study, we evaluated the species distribution of 51 clinical and 8 environmental Rhodotorula species isolates using the ID32C system and internal transcribed spacer (ITS) sequencing. Antifungal susceptibility testing and biofilm formation capability using a crystal violet staining assay were performed. Using ITS sequencing as the gold standard, the clinical isolates were identified as follows: 44 R. mucilaginosa isolates, 2 R. glutinis isolates, 2 R. minuta isolates, 2 R. dairenensis isolates, and 1 Rhodosporidium fluviale isolate. The environmental isolates included 7 R. mucilaginosa isolates and 1 R. slooffiae isolate. Using the ID32C system, along with a nitrate assimilation test, only 90.3% of the isolates tested were correctly identified. In the biofilm formation assay, R. mucilaginosa and R. minuta exhibited greater biofilm formation ability compared to the other Rhodotorula species; the clinical isolates of R. mucilaginosa showed greater biofilm formation compared to the environmental isolates (P = 0.04). Amphotericin B showed good in vitro activity (MIC ≤ 1 μg/ml) against planktonic cells, whereas voriconazole and posaconazole showed poor activity (MIC50/MIC90, 2/4 μg/ml). Caspofungin and fluconazole MICs were consistently high for all isolates tested (≥64 μg/ml and ≥ 4 μg/ml, respectively). In this study, we emphasized the importance of molecular methods to correctly identify Rhodotorula species isolates and non-R. mucilaginosa species in particular. The antifungal susceptibility profile reinforces amphotericin B as the antifungal drug of choice for the treatment of Rhodotorula infections. To our knowledge, this is the first study evaluating putative differences in the ability of biofilm formation among different Rhodotorula species.  相似文献   
50.
The paper presents the research results of lymphoangionodulary anastomosis perfusion properties in breast cancer. We have carried out the detailed study of 100 axillary lymph nodes affected with metastatic breast cancer and removed them using the method of sonolipodestruction ex vivo. The results obtained in the course of the study provide a basis for a new look at the problems of lymphodynamics in metastatic damage of a lymph system.  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