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   315篇
  免费   34篇
耳鼻咽喉   1篇
儿科学   2篇
妇产科学   3篇
基础医学   35篇
口腔科学   2篇
临床医学   15篇
内科学   66篇
皮肤病学   3篇
神经病学   11篇
特种医学   5篇
外科学   108篇
预防医学   48篇
眼科学   5篇
药学   36篇
肿瘤学   9篇
  2021年   7篇
  2020年   3篇
  2018年   3篇
  2017年   3篇
  2016年   5篇
  2015年   3篇
  2014年   5篇
  2013年   10篇
  2012年   12篇
  2011年   20篇
  2010年   9篇
  2009年   8篇
  2008年   14篇
  2007年   14篇
  2006年   19篇
  2005年   5篇
  2004年   5篇
  2003年   8篇
  2002年   8篇
  2001年   12篇
  2000年   13篇
  1999年   12篇
  1998年   4篇
  1997年   4篇
  1995年   3篇
  1993年   4篇
  1992年   6篇
  1991年   8篇
  1990年   6篇
  1989年   4篇
  1988年   3篇
  1987年   7篇
  1986年   8篇
  1985年   7篇
  1974年   3篇
  1973年   7篇
  1972年   3篇
  1971年   5篇
  1969年   3篇
  1968年   5篇
  1967年   4篇
  1966年   6篇
  1961年   3篇
  1959年   3篇
  1943年   2篇
  1940年   2篇
  1939年   2篇
  1936年   2篇
  1935年   2篇
  1934年   4篇
排序方式: 共有349条查询结果,搜索用时 33 毫秒
1.
2.
3.
4.
Background Candida auris is an emerging multidrug-resistant fungal pathogen associated with bloodstream, wound and other infections, especially in critically ill patients. C. auris carriage is persistent and is difficult to eradicate from the hospital environment.AimWe aimed to pilot admission screening for C. auris in intensive care units (ICUs) in England to estimate prevalence in the ICU population and to inform public health guidance.MethodsBetween May 2017 and April 2018, we screened admissions to eight adult ICUs in hospitals with no previous cases of C. auris, in three major cities. Swabs were taken from the nose, throat, axilla, groin, perineum, rectum and catheter urine, then cultured and identified using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). Patient records were linked to routine ICU data to describe and compare the demographic and health indicators of the screened cohort with a national cohort of ICU patients admitted between 2016 and 2017.ResultsAll C. auris screens for 921 adults from 998 admissions were negative. The upper confidence limit of the pooled prevalence across all sites was 0.4%. Comparison of the screened cohort with the national cohort showed it was broadly similar to the national cohort with respect to demographics and co-morbidities.ConclusionThese findings imply that C. auris colonisation among patients admitted to ICUs in England is currently rare. We would not currently recommend widespread screening for C. auris in ICUs in England. Hospitals should continue to screen high-risk individuals based on local risk assessment.  相似文献   
5.
Migrants and recent immigrants in the US constitute a large population that is vulnerable to HIV. From March 2005 to February 2007, three community-based organizations conducted rapid HIV testing among migrants in five states. Participants were asked to complete a survey on sociodemographics, HIV-risk behaviors, and HIV-testing histories with the aim of understanding factors associated with HIV testing. Among 5,247 persons tested, 6 (0.1 %) were HIV-positive. Among 3,135 persons who completed surveys, more than half had never been tested for HIV previously (59 %). Participants reported high levels of HIV-risk behaviors in the past year, including 2 or more sex partners (45 %), sex while high/drunk (30 %), and transactional sex (29 %). Multivariate analysis identified several factors independently associated with decreased likelihood of prior HIV testing, including poor spoken English. Continued efforts are needed to ensure that migrant populations have improved access to HIV testing and prevention services. Understanding factors associated with migrants’ lack of previous HIV testing may help focus these efforts.  相似文献   
6.

BACKGROUND:

Severe alcoholic hepatitis (AH) is associated with a substantial risk for short-term mortality.

OBJECTIVES:

To identify prognostic factors and validate well-known prognostic models in a Canadian population of patients hospitalized for AH.

METHODS:

In the present retrospective study, patients hospitalized for AH in Calgary, Alberta, between January 2008 and August 2012 were included. Stepwise logistic regression models identified independent risk factors for 90-day mortality, and the discrimination of prognostic models (Model for End-stage Liver Disease [MELD] and Maddrey discriminant function [DF]) were examined using areas under the ROC curves.

RESULTS:

A total of 122 patients with AH were hospitalized during the study period; the median age was 49 years (interquartile range [IQR] 42 to 55 years) and 60% were men. Median MELD score and Maddrey DF on admission were 21 (IQR 18 to 24) and 45 (IQR 26 to 62), respectively. Seventy-three percent of patients received corticosteroids and/or pentoxifylline, and the 90-day mortality was 17%. Independent predictors of mortality included older age, female sex, international normalized ratio, MELD score and Maddrey DF (all P<0.05). For discrimination of 90-day mortality, the areas under the ROC curves of the prognostic models (MELD 0.64; Maddrey DF 0.68) were similar (P>0.05). At optimal cut-offs of ≥22 for MELD score and ≥37 for Maddrey DF, both models excluded death with high certainty (negative predictive values 90% and 96%, respectively).

CONCLUSIONS:

In patients hospitalized for AH, well-known prognostic models can be used to predict 90-day mortality, particularly to identify patients with a low risk for death.  相似文献   
7.
8.
Frailty is one of the geriatric syndromes and has an important relationship with mortality and morbidity. The aim of this study is to present the characteristics, prevalence, and related factors of frailty in older adults in our country. The study included 1126 individuals over 65 years of age from 13 centers. Frailty was evaluated using the Fried Frailty criteria, and patients were grouped as “frail,” “pre-frail,” and “non-frail.” Nutritional status was assessed with “Mini Nutritional Test,” psychological status with the “Center for Epidemiological Studies Depression Scale-CES-D,” and additional diseases with the “Charlson Comorbidity index.” Approximately 66.5 % of the participants were between 65 and 74 years of age and 65.7 % were women. Some 39.2 and 43.3 % of the participants were rated as frail and pre-frail, respectively. The multinomial logistic regression analysis was used to determine the factors associated with frailty. It was observed that age, female gender, low education level, being a housewife, living with the family, being sedentary, presence of an additional disease, using 4 or more drugs/day, avoiding to go outside, at least one visit to any emergency department within the past year, hospitalization within the past year, non-functional ambulation, and malnutrition increased the risk of frailty (p < 0.05). Establishing the factors associated with frailty is highly important for both clinical practice and national economy. This is the first study on this subject in our country and will provide guidance in determining treatment strategies.  相似文献   
9.
Our health care system continues to undergo transformation in a context of extreme financial pressures. New models of care delivery and financing challenge us to rethink our practices as individual surgeons and as system participants. Understanding the fiscal realities of health care and how we are perceived by health care policy makers can help us to be meaningful participants in channeling reform to create better delivery systems for our patients. This article presents some background information about health care in America with a focus on government programs, and shares insights from my health care policy colleagues.  相似文献   
10.
Phosphatidylcholine (PC) is the major glycerophospholipid in eukaryotic cells and is an essential component in all cellular membranes. The biochemistry of de novo PC synthesis by the Kennedy pathway is well established, but less is known about the physiological functions of PC. We identified two unrelated patients with defects in the Kennedy pathway due to biallellic loss-of-function mutations in phosphate cytidylyltransferase 1 alpha (PCYT1A), the rate-limiting enzyme in this pathway. The mutations lead to a marked reduction in PCYT1A expression and PC synthesis. The phenotypic consequences include some features, such as severe fatty liver and low HDL cholesterol levels, that are predicted by the results of previously reported liver-specific deletion of murine Pcyt1a. Both patients also had lipodystrophy, severe insulin resistance, and diabetes, providing evidence for an additional and essential role for PCYT1A-generated PC in the normal function of white adipose tissue and insulin action.All living cells are surrounded by a lipid membrane. Eukaryotic cells also contain several internal membrane-bound organelles, which enable them to compartmentalize related biological functions and thereby to enhance the efficiency of these processes. Phospholipids are the predominant component of these membranes. Their hydrophilic head groups interact with the cytosol, whereas their hydrophobic side chains are either buried within the hydrophobic interior of a typical membrane bilayer or interact with the hydrophobic neutral lipid core of lipoproteins and lipid droplets (LDs). Phospholipids are generally defined by their organic head group with phosphatidylcholine (PC) constituting over 50% of all membrane phospholipids. PC was first isolated in the 19th century and the major enzymatic pathway involved in its synthesis was revealed by Kennedy and Weiss (1) in the 1950s. Cells synthesize PC in three consecutive steps (Fig. 1A): choline kinase phosphorylates choline before choline phosphate cytidylyltransferase 1 α (encoded by the PCYT1A gene) generates the high-energy donor CDP-choline in the rate-limiting step of the pathway. In the last step, DAG:CDP-choline cholinephosphotransferase (CPT) uses CDP-choline and diacylglycerol (DAG) to form PC (2, 3).Open in a separate windowFig. 1.Cosegregation of biallelic PCYT1A mutations with fatty liver, low HDL cholesterol levels, lipodystrophy, insulin-resistant diabetes, and short stature. (A) Schematic illustration of the Kennedy PC synthesis pathway. CK, choline kinase; CPT, CDP-choline:1,2-diacylglycerol cholinephosphotransferase; PCYT1A, choline-phosphate cytidylyltransferase A, CTP:phosphocholine-cytidylyltransferase. (B) Family pedigrees of both probands demonstrating that only compound heterozygous carriers of PCYT1A mutations manifest fatty liver (red), low HDL cholesterol (blue), lipodystrophy (yellow), and insulin resistance/type 2 diabetes (T2DM) (green). PCYT1A mutation status, height (Ht.), and body mass index (BMI) are indicated below each individual’s symbol. ND, not determined; WT, wild type. (C) The location of PCYT1A mutations E280del, V142M, and 333fs in relation to known functional domains of PCYT1A. Domain M, membrane binding domain; domain P, phosphorylated region. (D) Conservation around the V142(red*) and E280(red*) mutation sites. Sequence alignment of representative metazoan sequences in the region surrounding the mutated residues. Hydrophobic (blue) and polar (green) residues interacting with V142 are highlighted. Only residues different from the human sequence are shown. Sequence IDs: human (Homo sapiens) P49585, zebrafish (Danio rerio) F1QEN6, sea squirt (Ciona intestinalis) XP_002130773.1, sea urchin (Strongylocentrotus purpuratus) H3I3V9, water flee (Daphnia pulex) E9G1P5, Drosophila (D. melanogaster) Q9W0D9, Caenorhabditis (C. elegans) P49583, Trichoplax (T. adherens) B3RI62. (E and F) Structure of the catalytic domain of PCYT1A highlighting the role of V142M in the core packing. The two chains in the dimer are shown in yellow and gray; the residues and the secondary structure units are highlighted in color in the yellow monomer A: loop L3 with V142, red; α-helix, green; and the interacting β-sheet, blue. The residues packing with V142 are shown in ball-and-stick and space-filling representations, the dimer stabilizing R140 is shown in ball-and-stick colored according to the atom type. E is a global view, and F is a zoomed-in view of the catalytic core.Membrane phospholipids are a defining feature of advanced life-forms so it is perhaps not surprising that the pathways involved in their synthesis are ancient, and mutations affecting them are rarely tolerated in evolution. Here, we describe the identification and characterization of pathogenic human loss-of-function mutations affecting the eponymous Kennedy pathway.  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