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   2197篇
  免费   208篇
  国内免费   41篇
耳鼻咽喉   20篇
儿科学   76篇
妇产科学   63篇
基础医学   325篇
口腔科学   29篇
临床医学   262篇
内科学   480篇
皮肤病学   39篇
神经病学   129篇
特种医学   123篇
外科学   347篇
综合类   51篇
一般理论   1篇
预防医学   238篇
眼科学   42篇
药学   156篇
中国医学   9篇
肿瘤学   56篇
  2022年   22篇
  2021年   23篇
  2020年   18篇
  2019年   24篇
  2018年   27篇
  2017年   29篇
  2016年   32篇
  2015年   38篇
  2014年   51篇
  2013年   95篇
  2012年   106篇
  2011年   109篇
  2010年   77篇
  2009年   69篇
  2008年   77篇
  2007年   88篇
  2006年   70篇
  2005年   73篇
  2004年   77篇
  2003年   78篇
  2002年   76篇
  2001年   70篇
  2000年   64篇
  1999年   60篇
  1998年   45篇
  1997年   35篇
  1996年   25篇
  1995年   33篇
  1994年   25篇
  1993年   25篇
  1992年   60篇
  1991年   56篇
  1990年   61篇
  1989年   56篇
  1988年   50篇
  1987年   35篇
  1986年   38篇
  1985年   38篇
  1984年   24篇
  1983年   31篇
  1982年   19篇
  1981年   16篇
  1980年   21篇
  1979年   21篇
  1978年   18篇
  1976年   18篇
  1975年   17篇
  1972年   14篇
  1969年   20篇
  1968年   15篇
排序方式: 共有2446条查询结果,搜索用时 0 毫秒
61.
AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease.  相似文献   
62.
The present article reports a case involving an immunocompetent, previously well child who, despite two previous doses of inactivated poliovirus vaccine, developed severe flaccid paralysis consistent with polio after receiving oral polio vaccine.  相似文献   
63.
O-linked β-N-acetylglucosamine (O-GlcNAc) is a reversible posttranslational modification found on hundreds of nuclear and cytoplasmic proteins in higher eukaryotes. Despite its ubiquity and essentiality in mammals, functional roles for the O-GlcNAc modification remain poorly defined. Here we develop a combined genetic and chemical approach that enables introduction of the diazirine photocrosslinker onto the O-GlcNAc modification in cells. We engineered mammalian cells to produce diazirine-modified O-GlcNAc by expressing a mutant form of UDP-GlcNAc pyrophosphorylase and subsequently culturing these cells with a cell-permeable, diazirine-modified form of GlcNAc-1-phosphate. Irradiation of cells with UV light activated the crosslinker, resulting in formation of covalent bonds between O-GlcNAc-modified proteins and neighboring molecules, which could be identified by mass spectrometry. We used this method to identify interaction partners for the O-GlcNAc-modified FG-repeat nucleoporins. We observed crosslinking between FG-repeat nucleoporins and nuclear transport factors, suggesting that O-GlcNAc residues are intimately associated with essential recognition events in nuclear transport. Further, we propose that the method reported here could find widespread use in investigating the functional consequences of O-GlcNAcylation.  相似文献   
64.
65.
Modern population based oral health management requires a complete understanding of the impact of disease in order to provide efficient and effective oral health care and guidance. Periodontitis is an important cause of tooth loss and has been shown to be associated with a number of systemic conditions. The impact of oral conditions and disorders on quality of life has been extensively studied. However, the impact of periodontitis on quality of life has received less attention. This review summarizes the literature on the impact of periodontitis on oral health‐related quality of life (OHRQoL). Relevant publications were identified after searching the MEDLINE and EMBASE electronic databases. Screening of titles and abstracts and data extraction was conducted. Only observational studies were included in this review. Most of the reviewed studies reported a negative impact of periodontitis on OHRQoL. However, the reporting standards varied across studies. Moreover, most of the studies were conducted in developed countries.  相似文献   
66.
Osteoclasts are multinucleated myeloid lineage cells formed in response to macrophage colony‐stimulating factor (M‐CSF) and receptor activator of NF‐κB ligand (RANKL) by fusion of bone marrow–derived precursors that circulate in the blood and are attracted to sites of bone resorption in response to factors, such as sphingosine‐1 phosphate signaling. Major advances in understanding of the molecular mechanisms regulating osteoclast functions have been made in the past 20 years, mainly from mouse and human genetic studies. These have revealed that osteoclasts express and respond to proinflammatory and anti‐inflammatory cytokines. Some of these cytokines activate NF‐κB and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling to induce osteoclast formation and activity and also regulate communication with neighboring cells through signaling proteins, including ephrins and semaphorins. Osteoclasts also positively and negatively regulate immune responses and osteoblastic bone formation. These advances have led to development of new inhibitors of bone resorption that are in clinical use or in clinical trials; and more should follow, based on these advances. This article reviews current understanding of how bone resorption is regulated both positively and negatively in normal and pathologic states. © 2013 American Society for Bone and Mineral Research.  相似文献   
67.
68.
A randomized controlled study called Anticipatory and Preventative Team Care (APTCare) explored a new role for nurse practitioners (NPs) within a multidisciplinary team. The aim of the study was to evaluate whether integrating NPs and a pharmacist was an effective approach for the management of patients living with multiple chronic illnesses. Over an 18-month period, three part-time NPs and a pharmacist became part of a rural Family Health Network (FHN). They established relationships with study patients and collaborated to provide optimum care. Each NP had 40 patients, all of whom received care in the home. Study results showed that an initial home visit was invaluable for establishing a care plan, developing a relationship with the patient and assessing the home environment. Ongoing monitoring at home, however, was found to be an inefficient use of the NP role. By the end of the study, all clinicians agreed that the NP role had been successfully integrated into the multidisciplinary team.  相似文献   
69.
70.
Optic neuropathy (ON) is a highly disabling complication of fibrous dysplasia (FD). The optimal test for identifying and monitoring ON in FD is unknown. Optical coherence tomography (OCT) is an imaging modality that detects retinal nerve fiber layer (RNFL) thinning, a sign of optic nerve atrophy. The purpose of this study was to (i) assess the ability of OCT RNFL thickness measurements to identify ON in FD; (ii) compare the performance of RNFL thickness to computed tomography measurements; and (iii) examine changes in RNFL thickness over time to assess disease progression. A retrospective cohort study was performed to assess subjects (n = 70) who underwent neuro-ophthalmologic examination, including OCT. The diagnostic utility of RNFL thickness was determined using receiver operator characteristic (ROC) curve analysis, and the accuracy was compared with computed tomography measurements. The relationship between RNFL thickness and age was assessed cross-sectionally, using generalized estimating equation methodology, and longitudinally, using a generalized mixed model. Eleven subjects were identified with ON. RNFL thickness identified ON (area under curve = 0.997, p < 0.0001) with sensitivity and specificity of 100% and 95%, respectively, when using the diagnostic criterion of ≤71 μm. RNFL thickness outperformed computed tomography measurements of optic canal narrowing and optic nerve stretch. Subjects with ON exhibited a greater decrease in RNFL thickness with each year of age (−0.70 μm/year, p < 0.001) than subjects with normal vision (−0.16 μm/year, p < 0.05). When assessed longitudinally, subjects with normal vision demonstrated an increase in RNFL thickness until approximately age 20 years that decreased thereafter. In contrast, subjects with ON exhibited an earlier decrease in RNFL thickness during adolescence. In conclusion, RNFL thickness of ≤71 μm accurately identified ON in this population. By establishing the difference in rate of RNFL thinning in patients with and without ON, clinicians may distinguish between patients at risk for ON and intervene before irreversible damage. © 2020 American Society for Bone and Mineral Research.  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