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   4562篇
  免费   254篇
  国内免费   45篇
耳鼻咽喉   19篇
儿科学   134篇
妇产科学   95篇
基础医学   597篇
口腔科学   117篇
临床医学   415篇
内科学   1228篇
皮肤病学   82篇
神经病学   520篇
特种医学   126篇
外科学   434篇
综合类   14篇
一般理论   3篇
预防医学   234篇
眼科学   100篇
药学   302篇
中国医学   5篇
肿瘤学   436篇
  2024年   8篇
  2023年   54篇
  2022年   154篇
  2021年   234篇
  2020年   142篇
  2019年   157篇
  2018年   178篇
  2017年   106篇
  2016年   131篇
  2015年   181篇
  2014年   197篇
  2013年   238篇
  2012年   370篇
  2011年   379篇
  2010年   211篇
  2009年   191篇
  2008年   272篇
  2007年   228篇
  2006年   239篇
  2005年   189篇
  2004年   168篇
  2003年   175篇
  2002年   138篇
  2001年   54篇
  2000年   63篇
  1999年   38篇
  1998年   22篇
  1997年   11篇
  1996年   15篇
  1995年   14篇
  1994年   6篇
  1993年   10篇
  1992年   23篇
  1991年   27篇
  1990年   14篇
  1989年   30篇
  1988年   20篇
  1987年   22篇
  1986年   14篇
  1985年   19篇
  1984年   13篇
  1983年   12篇
  1982年   6篇
  1979年   9篇
  1977年   7篇
  1976年   9篇
  1973年   7篇
  1971年   5篇
  1970年   6篇
  1968年   9篇
排序方式: 共有4861条查询结果,搜索用时 31 毫秒
91.
Annals of Nuclear Medicine - [18F] fluorodeoxyglucose positron emission tomography/computed tomography ([18F] FDG-PET/CT) is used for diagnosis, staging, response assessment and prognosis...  相似文献   
92.
93.
OBJECTIVE: Studies of memory T cells transferred with the graft are relevant to better understand the early immune reconstitution of patients given autologous bone marrow transplantation (A-BMT). A critical question is whether memory T cells resident in bone marrow (BM) of patients with hematological malignancies are resistant to either pretransplant chemotherapy or ex vivo pharmacological purging. PATIENTS AND METHODS: To address these issues, we evaluated the frequency of tetanus-toxoid (TT)-specific proliferating T-cell precursors (TT-PTCp) in BM and peripheral blood (PB) of eight patients with acute myeloid leukemia (AML) given A-BMT after in vitro purging of BM with mafosfamide. Patients were studied at the time of BM harvesting and five of them also after A-BMT. RESULTS: The range of TT-PTCp frequencies found after A-BMT were comparable with those observed in PB and in BM at the time of harvesting and did not differ significantly from those of eight age-matched healthy subjects who donated BM for a human leukocyte antigen-identical sibling. TT-PTCp frequencies in BM, studied before and after ex vivo purging, appeared not to be affected by incubation with mafosfamide. We also compared the T-cell receptor (TCR)-Vbeta-repertoire usage of TT-specific T-cell lines (TT-TCL) in BM of patients at the time of harvesting and in their PB 2 months after transplantation. The same TCR-clonotypes were detected in TT-TCL at time of harvesting and after A-BMT. CONCLUSION: These data indicate that BM-resident memory T cells of patients with AML are resistant to both pretransplant chemotherapy and ex vivo pharmacological purging and may contribute to immune reconstitution after A-BMT.  相似文献   
94.
Summary Withdrawal of exogenous insulin and a subsequent fast (24 h) of alloxan diabetic rats stimulated rates of gluconeogenesis, ureogenesis, ketogenesis, and amino acid release by in situ perfused livers when compared to those from normal, fasted rats. The contribution of liver glycogen to the high rates of gluconeogenesis observed with the diabetic liver could be excluded. Perfusate lactate concentrations remained constant during the period when the elevated rate of gluconeogenesis was observed with diabetic liver. Addition of insulin as a bolus (750 mU) and continuous infusion (12.5 mU/min) to the perfusion medium of diabetic livers resulted in constant perfusate levels of glucose, urea and -amino nitrogen indicating a suppression of the catabolic processes present in the fasted, diabetic liver. The rate of ketogenesis was also slowed by insulin to about half the rate prior to addition of the hormone. These data indicate that insulin has an immediate anti-catabolic effect in the perfused, diabetic liver.  相似文献   
95.
96.
Pancreatic and gut hormones have been measured in 39 patients with chronic pancreatitis, 16 of whom had severe pancreatic insufficiency. Patients with pancreatic insufficiency had significantly diminished fasting levels and postprandial rises of pancreatic polypeptide which were less than 20% of normal. Patients with chronic pancreatitis, with or without exocrine insufficiency, had two- to threefold higher plasma levels of motilin and enteroglucagon than controls. Plasma levels of insulin, pancreatic glucagon, gastric inhibitory polypeptide and gastrin were similar to normal in these patients. The pattern of response of these hormones to a test breakfast differs markedly from those seen in other gut disease states and may reflect pathophysiological mechanisms.  相似文献   
97.
Pentraxin 3 (PTX3) is a soluble pattern recognition receptor that binds with high affinity and selectivity to fibroblast growth factor‐2 (FGF2), thus inhibiting its pro‐angiogenic activity. Here we investigated the effects of PTX3 on monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) patient‐derived bone marrow (BM) plasma cells (PCs), endothelial cells (ECs), and fibroblasts (FBs), and assessed whether PTX3 can modulate the cross‐talk between PCs and those microenvironment cells. PTX3 and FGF2 expression was evaluated by ELISA. Functional studies, including cell viability, wound healing, chemotaxis, and Matrigel® assays, were performed on MGUS and MM ECs and FBs upon the PTX3 treatment. Through western blot PTX3‐induced modulation in FGF2/FGF receptor signalling pathways was evaluated in MGUS and MM ECs and FBs through western blot. Co‐cultures between MM ECs/FBs and human PC lines were used to evaluate possible PTX3 indirect effects on MM PCs. Adhesion molecules were studied by flow cytometry. PTX3 provides a direct time‐ and dose‐dependent apoptotic effect on MM ECs and FBs, but not on either MM primary PCs or human PC lines. PTX3 inhibits migration of MM ECs and FBs in a dose‐dependent manner, and impacts in vitro and in vivo FGF2‐mediated MM angiogenesis. Co‐cultures of PCs and ECs/FBs show that PTX3 treatment indirectly impairs PC viability and adhesion. We conclude that PTX3 is an anti‐angiogenic factor in MM and behaves as a cytotoxic molecule on MM cells by inhibiting the cross‐talk between PCs and ECs/FBs. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
98.
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that is accompanied by neurodevelopmental differences in regional cortical volume (CV), and a potential layer‐specific pathology. Conventional measures of CV, however, do not indicate how volume is distributed across cortical layers. In a sample of 92 typically developing (TD) controls and 92 adult individuals with ASD (aged 18–52 years), we examined volumetric gradients by quantifying the degree to which CV is weighted from the pial to the white surface of the brain. Overall, the spatial distribution of Frustum Surface Ratio (FSR) followed the gyral and sulcal pattern of the cortex and approximated a bimodal Gaussian distribution caused by a linear mixture of vertices on gyri and sulci. Measures of FSR were highly correlated with vertex‐wise estimates of mean curvature, sulcal depth, and pial surface area, although none of these features explained more than 76% variability in FSR on their own. Moreover, in ASD, we observed a pattern of predominant increases in the degree of FSR relative to TD controls, with an atypical neurodevelopmental trajectory. Our findings suggest a more outward‐weighted gradient of CV in ASD, which may indicate a larger contribution of supragranular layers to regional differences in CV.  相似文献   
99.
ObjectivesThis review explores the literature about the status and influence of statutory regulation in healthcare with a focus on medical imaging. It summarises the status of regulation in Australia for radiographers and sonographers, with brief reference to the global situation. The role of regulation is explored in terms of its evolution, function and effect on professional behaviours.Key findingsReports of medical errors, sentinel events and professional misconduct in healthcare have raised concern about how health care professionals are regulated. Patient-centric healthcare delivery has changed how people interact with healthcare, contributing to the development of statutory regulation for many healthcare professions.In Australia, the Health Practitioner Regulation National Law (The National Law) 2009, established the National Registration and Accreditation Scheme (NRAS) in order to practice. Not all health care professions are included in the scheme. In medical imaging, radiographers are included but sonographers are a notable exception.Regulation is designed to positively influence practitioners' professional behaviours. The available evidence however is limited, but suggests that under certain circumstances, it can negatively impact practitioners’ professional behaviours.ConclusionStatutory regulation has been implemented to address serious issues highlighted in reports of medical errors and professional misconduct, but it may have unintended consequences on the professional behaviours of practitioners. Limited research means the relationship between statutory regulation of healthcare practitioners and its impact upon professional behaviours remains unclear.Implications for practiceIf statutory regulation of healthcare professionals is to achieve its aim of protecting the public, it is imperative that we understand the impact that it has on professional behaviours. This review highlights that it can negatively impact professional behaviours which may be detrimental to patient's safety.  相似文献   
100.
Neurological Sciences - Monoclonal antibodies targeting the calcitonin gene-related peptide, including erenumab, are migraine-specific preventive treatments, whose long-term effectiveness has still...  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