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   657篇
  免费   54篇
  国内免费   5篇
耳鼻咽喉   4篇
儿科学   23篇
妇产科学   22篇
基础医学   99篇
口腔科学   19篇
临床医学   93篇
内科学   136篇
皮肤病学   12篇
神经病学   29篇
特种医学   8篇
外科学   59篇
综合类   2篇
一般理论   1篇
预防医学   71篇
眼科学   5篇
药学   70篇
中国医学   4篇
肿瘤学   59篇
  2023年   8篇
  2022年   22篇
  2021年   34篇
  2020年   13篇
  2019年   24篇
  2018年   36篇
  2017年   21篇
  2016年   13篇
  2015年   24篇
  2014年   32篇
  2013年   35篇
  2012年   48篇
  2011年   65篇
  2010年   30篇
  2009年   31篇
  2008年   40篇
  2007年   31篇
  2006年   27篇
  2005年   35篇
  2004年   44篇
  2003年   32篇
  2002年   26篇
  2001年   2篇
  2000年   1篇
  1999年   3篇
  1998年   5篇
  1997年   1篇
  1996年   5篇
  1995年   3篇
  1994年   2篇
  1993年   3篇
  1992年   1篇
  1990年   2篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
  1980年   2篇
  1979年   1篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1965年   1篇
  1962年   1篇
排序方式: 共有716条查询结果,搜索用时 15 毫秒
131.
Preventing and controlling the spread of multidrug-resistant (MDR) bacteria implicated in healthcare-associated infections is the greatest challenge of the health systems. In recent decades, research has shown the need for passive antibacterial protection of surfaces in order to reduce the microbial load and microbial biofilm development, frequently associated with transmission of infections. The aim of the present study is to analyze the efficiency of photocatalytic antimicrobial protection methods of surfaces using the new photocatalytic paint activated by light in the visible spectrum. The new composition is characterized by a wide range of analytical methods, such as UV-VIS spectroscopy, electron microscopy (SEM), X-ray powder diffraction (PXRD) or X-ray photoelectron spectroscopy (XPS). The photocatalytic activity in the UV-A was compared with the one in the visible light spectrum using an internal method developed on the basis of DIN 52980: 2008-10 standard and ISO 10678—2010 standard. Migration of metal ions in the composition was tested based on SR EN1186-3: 2003 standard. The new photocatalytic antimicrobial method uses a type of photocatalytic paint that is active in the visible spectral range and generates reactive oxygen species with inhibitory effect against all tested microbial strains.  相似文献   
132.
The transforming growth factor‐beta (TGF‐β) signalling pathway plays an important role in tumor development and progression. We aimed at analyzing whether 7 different common variants in genes coding for 2 key members of the TGF‐β signalling pathway (TGFB1 and TGFBR1) are associated with bladder cancer risk and prognosis. A total of 1,157 cases with urothelial cell carcinoma of the bladder and 1,157 matched controls where genotyped for 3 single nucleotide polymorphisms (SNPs) in TGFB1 (rs1982073, rs1800472, rs1800471) and an additional 3 SNPs and 1 indel polymorphism in TGFBR1 (rs868, rs928180, rs334358 and rs11466445, respectively). In the case‐control study, we estimated odds ratios and 95% confidence intervals for each individual genetic variant using unconditional logistic regression adjusting for age, gender, study area and smoking status. Survival analysis was performed using the Kaplan‐Meier method and Cox models. The endpoints of interest were tumor relapse, progression and death from bladder cancer. All the SNPs analyzed showed a similar distribution among cases and controls. The distribution of the TGFBR1*6A allele (rs11466445) was also similar among cases and controls, indicating no association with bladder cancer risk. Similarly, none of the haplotypes was significantly associated with bladder cancer risk. Among patients with muscle‐invasive tumors, we found a significant association between TGFBR1‐rs868 and disease‐specific mortality with an allele dosage effect (p‐trend = 0.003). In conclusion, the genetic variants analyzed were not associated with an increased risk of bladder cancer. The association of TGFBR1‐rs868 with outcome should be validated in independent patient series. © 2008 Wiley‐Liss, Inc.  相似文献   
133.
This study investigates bidirectional associations between adolescents’ daily experiences of victimization and aggression perpetration within friendships. We investigated (a) across-day associations between victimization and aggression perpetration; (b) morning cortisol activity as a moderator of cross-day victimization and aggression links; and (c) potential sex differences in these patterns. For 4 consecutive days, 99 adolescents (Mage = 18.06, SD = 1.09, 46 females) reported whether they were victimized by or aggressive toward their friends. On three of these days, adolescents provided three morning saliva samples. Multilevel path analyses showed that across days, victimization and aggression were bidirectionally linked, but only for male adolescents. Additionally, for male adolescents, morning cortisol output (but not morning cortisol increase) moderated the association between victimization and next-day aggression; victimization predicted greater next-day aggression for boys with low, but not high, morning cortisol output. Findings implicate a physiological factor that may modify daily links between victimization and aggression in male adolescent friendships.  相似文献   
134.
135.
136.
Autosomal recessive hydrocephalus with aqueductal stenosis   总被引:1,自引:0,他引:1  
We report the case histories of three sisters with congenital hydrocephalus associated with stenosis of the cerebral aqueduct. The parents were a young consanguineous couple. In two cases hydrocephalus was detected before birth by ultrasonography. We consider these three cases to be of the rare autosomal form of hereditary hydrocephalus.  相似文献   
137.
Despite the importance of early recognition of metabolic bone disease (MBD) of prematurity, there is still significant variability in screening practices across institutions. We conducted an observational study of infants born at ≤32 weeks of gestation with a birth weight of ≤1500 g (n = 218) to identify clinical factors associated with biochemical indicators of MBD. Bone mineral status was assessed by measuring alkaline phosphatase and phosphate levels between weeks 3 and 5 of life. Two comparisons were performed after classifying infants as either MBD (cases) or non-MBD (controls), and as either high or low risk for MBD, as determined based on the results of MBD screening. In total, 27 infants (12.3%) were classified as cases and 96 (44%) as high-risk. Compared with controls, MBD infants had a significantly lower gestational age and birth weight, and a longer duration of parenteral nutrition and hospital stay. Respiratory outcomes were significantly poorer in high- versus low-risk infants. Multivariate logistic regression showed that birth weight was the only independent risk factor for MBD (odds ratio [OR]/100 g, 0.811; confidence interval [CI95%], 0.656–0.992; p = 0.045) and that birth weight (OR/100 g, 0.853; CI95%, 0.731–0.991; p = 0.039) and red blood cell transfusion (OR, 2.661; CI95%, 1.308–5.467; p = 0.007) were independent risk factors for high risk of MBD. Our findings provide evidence of risk factors for MBD that could help clinicians to individualize perinatal management. The association of red blood cell transfusion with MBD is a novel finding that may be related to iron overload and that merits further study.  相似文献   
138.
139.
140.

Introduction  

Recent studies have identified both the prognostic and predictive utility of determining the number of circulating tumour cells (CTC) in patients with solid cancers.  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