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   5325篇
  免费   441篇
  国内免费   14篇
耳鼻咽喉   38篇
儿科学   192篇
妇产科学   136篇
基础医学   625篇
口腔科学   127篇
临床医学   447篇
内科学   1166篇
皮肤病学   146篇
神经病学   651篇
特种医学   112篇
外科学   613篇
综合类   46篇
一般理论   9篇
预防医学   525篇
眼科学   35篇
药学   353篇
中国医学   17篇
肿瘤学   542篇
  2024年   28篇
  2023年   83篇
  2022年   152篇
  2021年   273篇
  2020年   200篇
  2019年   260篇
  2018年   263篇
  2017年   193篇
  2016年   172篇
  2015年   200篇
  2014年   269篇
  2013年   301篇
  2012年   445篇
  2011年   393篇
  2010年   211篇
  2009年   235篇
  2008年   311篇
  2007年   282篇
  2006年   258篇
  2005年   257篇
  2004年   224篇
  2003年   201篇
  2002年   165篇
  2001年   71篇
  2000年   49篇
  1999年   45篇
  1998年   30篇
  1997年   14篇
  1996年   10篇
  1995年   10篇
  1994年   7篇
  1993年   5篇
  1992年   18篇
  1991年   9篇
  1990年   25篇
  1989年   11篇
  1988年   9篇
  1987年   14篇
  1986年   9篇
  1985年   7篇
  1983年   4篇
  1977年   3篇
  1976年   6篇
  1975年   4篇
  1974年   8篇
  1973年   3篇
  1972年   6篇
  1970年   3篇
  1968年   3篇
  1966年   7篇
排序方式: 共有5780条查询结果,搜索用时 15 毫秒
1.
There is an unmet need to overcome nongenetic therapy-resistance to improve outcomes in AML, especially post-myeloproliferative neoplasm (MPN) secondary (s) AML. Studies presented describe effects of genetic knockout, degradation or small molecule targeted-inhibition of GFI1/LSD1 on active enhancers, altering gene-expressions and inducing differentiation and lethality in AML and (MPN) sAML cells. A protein domain-focused CRISPR screen in LSD1 (KDM1A) inhibitor (i) treated AML cells, identified BRD4, MOZ, HDAC3 and DOT1L among the codependencies. Our findings demonstrate that co-targeting LSD1 and one of these co-dependencies exerted synergistic in vitro lethality in AML and post-MPN sAML cells. Co-treatment with LSD1i and the JAKi ruxolitinib was also synergistically lethal against post-MPN sAML cells. LSD1i pre-treatment induced GFI1, PU.1 and CEBPα but depleted c-Myc, overcoming nongenetic resistance to ruxolitinib, or to BETi in post-MPN sAML cells. Co-treatment with LSD1i and BETi or ruxolitinib exerted superior in vivo efficacy against post-MPN sAML cells. These findings highlight LSD1i-based combinations that merit testing for clinical efficacy, especially to overcome nongenetic therapy-resistance in AML and post-MPN sAML.Subject terms: Acute myeloid leukaemia, Targeted therapies  相似文献   
2.
Abstract

Thematic analysis is a widely used, yet often misunderstood, method of qualitative data analysis. It is a useful and accessible tool for qualitative researchers, but confusion regarding the method’s philosophical underpinnings and imprecision in how it has been described have complicated its use and acceptance among researchers. In this Guide, we outline what thematic analysis is, positioning it in relation to other methods of qualitative analysis, and describe when it is appropriate to use the method under a variety of epistemological frameworks. We also provide a detailed definition of a theme, as this term is often misapplied. Next, we describe the most commonly used six-step framework for conducting thematic analysis, illustrating each step using examples from our own research. Finally, we discuss advantages and disadvantages of this method and alert researchers to pitfalls to avoid when using thematic analysis. We aim to highlight thematic analysis as a powerful and flexible method of qualitative analysis and to empower researchers at all levels of experience to conduct thematic analysis in rigorous and thoughtful way.  相似文献   
3.
4.
The need to understand how an intervention is received by the beneficiary community is well recognised and particularly neglected in the micro–health insurance (MHI) domain. This study explored the views and reactions of the beneficiary community of the redesigned Community Health Fund (CHF) implemented in the Dodoma region of Tanzania. We collected data from focus group discussions with 24 groups of villagers (CHF members and nonmembers) and in‐depth interviews with 12 key informants (enrolment officers and health care workers). The transcribed material was analysed thematically. We found that participants highly appreciate the scheme, but to be resolved are the challenges posed by the implementation strategies adopted. The responses of the community were nested within a complex pathway relating to their interaction with the implementation strategies and their ongoing reflections regarding the benefits of the scheme. Community reactions ranged from accepting to rejecting the scheme, demanding the right to receive benefit packages once enrolled, and dropping out of the scheme when it failed to meet their expectations. Reported drivers of the responses included intensity of CHF communication activities, management of enrolment procedures, delivery of benefit packages, critical features of the scheme, and contextual factors (health system and socio‐political context). This study highlights that scheme design and implementation strategies that address people's needs, voices, and values can improve uptake of MHI interventions. The study adds to the knowledge base on implementing MHI initiatives and could promote interests in assessing the response to interventions within the MHI domain and beyond.  相似文献   
5.
6.
Objectives The purpose of this qualitative study was to explore the infant safe sleep beliefs and occupational practices of lactation consultants and to determine if lactation consultants give advice to clients that is consistent with the American Academy of Pediatrics’ recommendations on this topic. Methods Focus groups were conducted with certified lactation consultants in two cities in Ohio. Participants discussed the role of lactation consultants, the infant sleep advice they provide to women, their views on the American Academy of Pediatrics’ infant safe sleep recommendations and related policies, and perceived benefits and barriers associated with providing infant safe sleep education as part of their work. A member-checking session was held to ensure the credibility of the findings. Results Four focus groups were conducted with 22 certified lactation consultants between September and November 2015. Major themes that emerged included: lactation consultants’ beliefs regarding the importance of bedsharing for supporting breastfeeding success; their disagreement with the infant safe sleep recommendations of the American Academy of Pediatrics; their frustration with policies that restrict consultants’ ability to discuss bedsharing; and the impact of infant safe sleep policies on their work and the advice they provide. Conclusions for Practice Lactation consultants interact with mothers of newborns at a critical time for infant safe sleep decision-making and may influence a woman’s choices related to this topic. Women may not be receiving messages from lactation consultants that are consistent with the infant safe sleep recommendations of the American Academy of Pediatrics.  相似文献   
7.
8.
Age-related changes in human sublingual glands: a post mortem study   总被引:1,自引:0,他引:1  
OBJECTIVES: To analyse age- and gender-related microscopic changes in sublingual glands obtained from human cadavers. STUDY DESIGN: One hundred eighty six human sublingual glands were obtained from 93 autopsies. Approximately five individuals of each gender per decade of life were allocated to three age groups: group I (0-30 years, n=26); group II (31-60 years, n=32) and group III (61-90 years, n=35). The specimens were fixed in 10% formalin and submitted to routine histological processing, and sections were stained with hematoxylin and eosin. RESULTS: Significant differences with increasing age were observed for the following microscopic aspects: acinar atrophy (r=0.26, p=0.0115); replacement of parenchyma by fibrous tissue (r=0.79, p<0.0001) and/or adipose tissue (r=0.63, p<0.0001); oncocytosis (r=0.61, p<0.0001); duct-like structures (chi(2)=14.68, p=0.0006) and congested blood vessels (chi(2)=7.18, p=0.0276). The mononuclear infiltrate changed from focal to diffuse with age (H=8.47, p=0.0144). No significant differences were observed between genders. CONCLUSIONS: The aging process starts with acinar atrophy, followed by the presence of duct-like structures and ends with the replacement of the parenchyma by fibrous and/or adipose tissue. The mononuclear infiltrate changes from focal to diffuse. No difference in the aging of the sublingual glands is observed between men and women.  相似文献   
9.
Otitis media with effusion (OME) is the most common cause of conductive hearing loss in children and is strongly associated with primary ciliary dyskinesia (PCD). Approximately half of the children with PCD require otolaryngology care, posing a major problem in this population. Early diagnosis of PCD is critical in these patients to minimise the collateral damage related to OME. The current gold standard for PCD diagnosis requires determining ciliary structure defects by transmission electron microscopy (TEM) or clearly documenting ciliary dysfunction via digital high-speed video microscopy (DHSV). Although both techniques are useful for PCD diagnosis, they have limitations and need to be supported by new methodologies, including genetic analysis of genes related to PCD. In this article, we review classical and recently associated mutations related to ciliary alterations leading to PCD, which can be useful for early diagnosis of the disease and subsequent early management of OME.  相似文献   
10.
Coronary spasm during coronary angiography for vasculopathy in children can be prevented by the intracoronary administration of nitroglycerin. We reviewed the anesthesia and catheterization reports and charts for pediatric transplant recipients who underwent angiography from 2005 through 2010. Correlation analysis was used to study the relation of post-injection systolic blood pressure (SBP) to nitroglycerin dose. Forty-one angiographic evaluations were performed on 25 patients (13 male and 12 female). Mean age was 9.9 ± 3.2 years (range, 3.3–16.1 yr). The mean total dose of nitroglycerin was 2.93 ± 1.60 µg/kg (range, 1–8 µg/kg).There was a significant drop between the baseline SBP (mean, 106 ± 21.6 mmHg) and the lowest mean SBP before nitroglycerin administration (78 ± 13.2, P <0.0001, paired t test). There was no significant additional change in SBP (mean after nitroglycerin administration, 80.7 ± 13.1 mmHg; P = 0.2). There was a significant drop in lowest heart rate between baseline (109 ± 16.5 beats/min) and before nitroglycerin administration (89 ± 14.3 beats/min; P <0.0001, paired t test). There was no significant additional change in heart rate (mean heart rate after nitroglycerin, 84 ± 17.7 beats/min; P = 0.09). There were 2 interventions for SBP before nitroglycerin and 2 after nitroglycerin. One child experienced a transient ST-T–segment change during angiography after nitroglycerin. In the highest dose range, the additional decrease in SBP was 7.2 mmHg (P=0.03). Routine intracoronary nitroglycerin administration in this dose range produced no significant changes in SBP or heart rate in children.Key words: Child, coronary angiography, coronary vasospasm/etiology, dose-response relationship, drug, heart transplantation/adverse effects, hemodynamics/drug effects, nitroglycerin/administration & dosage/therapeutic use, postoperative complications/therapy, retrospective studies, vasodilation/drug effectsAllograft coronary disease in children occurs with increasing frequency after transplantation, as a function of time. In a multicenter study,1 the incidence of coronary artery disease in children 5 years post-transplant was 17% of all recipients. Coronary angiography remains the gold standard in the detection of vasculopathy in heart-transplant recipients.2 Coronary artery spasm can complicate selective coronary angiography and result in myocardial ischemia. Coronary spasm can simulate the angiographic appearance of graft vasculopathy and cause diagnostic confusion.3 The spasm can arise from manipulation of the arterial wall by the catheter or from intraluminal injection of contrast material. In cardiac transplant recipients, coronary artery spasm has been reported in as many as 4.9% of coronary angiograms.3In adults, intracoronary nitroglycerin is routinely administered during coronary angiography to prevent coronary artery spasm.4 In children, however, safety and dosage guidelines for intracoronary nitroglycerin have not yet been firmly established. A dose of 3 µg/kg can be extrapolated by weight from the established adult dose of 200 µg; this dose was used in a study of children after the arterial switch operation and was shown to produce coronary vasodilation—with a small reduction in systolic blood pressure (SBP) and no noteworthy change in heart rate—in a control group of patients.5,6We previously reported a case of coronary artery spasm during routine coronary angiographic monitoring in a 9-year-old boy who had undergone heart transplantation as an infant.7 After left main coronary artery injection of contrast material, the patient''s left anterior descending and left circumflex coronary arteries appeared to be diffusely narrow, and he developed marked ST-segment elevation, hypotension, and ventricular tachycardia. After cardiopulmonary resuscitation, he recovered uneventfully and displayed normal systolic function. Coronary angiography one month later, with the administration of intracoronary nitroglycerin before the injection of contrast material, revealed normal coronary artery diameter and was accomplished without complication.Since 2005, intracoronary nitroglycerin has routinely been used in pediatric transplant patients during biennial selective coronary angiographic monitoring at our institution. The purpose of the study is to report our experience with the routine use of intracoronary nitroglycerin for coronary angiography in children: its effects on blood pressure, on heart rate, and on the occurrence of arrhythmia and ST-segment elevation.  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