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   37985篇
  免费   1695篇
  国内免费   297篇
耳鼻咽喉   276篇
儿科学   679篇
妇产科学   425篇
基础医学   4974篇
口腔科学   1111篇
临床医学   2235篇
内科学   9359篇
皮肤病学   920篇
神经病学   2559篇
特种医学   1294篇
外科学   6764篇
综合类   155篇
一般理论   1篇
预防医学   1053篇
眼科学   763篇
药学   2205篇
  2篇
中国医学   134篇
肿瘤学   5068篇
  2024年   87篇
  2023年   257篇
  2022年   561篇
  2021年   967篇
  2020年   514篇
  2019年   659篇
  2018年   866篇
  2017年   683篇
  2016年   802篇
  2015年   825篇
  2014年   1112篇
  2013年   1422篇
  2012年   2300篇
  2011年   2719篇
  2010年   1531篇
  2009年   1258篇
  2008年   2315篇
  2007年   2538篇
  2006年   2373篇
  2005年   2567篇
  2004年   2482篇
  2003年   2465篇
  2002年   2468篇
  2001年   412篇
  2000年   356篇
  1999年   480篇
  1998年   592篇
  1997年   466篇
  1996年   449篇
  1995年   379篇
  1994年   337篇
  1993年   310篇
  1992年   258篇
  1991年   238篇
  1990年   224篇
  1989年   215篇
  1988年   186篇
  1987年   129篇
  1986年   124篇
  1985年   111篇
  1984年   120篇
  1983年   102篇
  1982年   83篇
  1981年   95篇
  1980年   90篇
  1979年   82篇
  1978年   52篇
  1977年   38篇
  1976年   29篇
  1973年   38篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

Objective

This study assessed the association between the timing of first epinephrine administration (EA) and the neurological outcomes following out-of-hospital cardiac arrests (OHCAs) with both initial shockable and non-shockable rhythms.

Methods

This was a post-hoc analysis of a multicenter prospective cohort study (SOS-KANTO 2012), which registered OHCA patients in the Kanto region of Japan from January 2012 to March 2013. We included consecutive adult OHCA patients who received epinephrine. The primary result included 1-month favorable neurological outcomes defined as cerebral performance category (CPC) 1 or 2. Secondary results included 1-month survival and return of spontaneous circulation (ROSC) after arrival at the hospital. Multivariable logistic regression analysis determined the association between delay per minute of the time from call to first EA in both pre- or in-hospital settings and outcomes.

Results

Of the 16,452 patients, 9344 were eligible for our analyses. In univariable analysis, the delay in EA was associated with decreased favorable neurological outcomes only when the initial rhythm was a non-shockable rhythm. In multivariable analyses, delay in EA was associated with decreased ROSC (adjusted odds ratio [OR] for one minute delay, 0.97; 95% confidence interval [CI], 0.96–0.98) and 1-month survival (adjusted OR, 0.95; 95% CI, 0.92–0.97) when the initial rhythm was a non-shockable rhythm, whereas during a shockable rhythm, delay in EA was not associated with decreased ROSC and 1-month survival.

Conclusions

While assessing the effectiveness of epinephrine for OHCA, we should consider the time-limited effects of epinephrine. Additionally, consideration of early EA based on the pathophysiology is needed.  相似文献   
2.
3.
ABSTRACT

Household effluents are predominantly treated by wastewater treatment plants (WWTPs). Other treatment methods, which were examined in this study, are also used in the countryside. These treatment modes include (1) onsite toilet wastewater treatment system (OTWTS), (2) onsite wastewater treatment system (OWTS), (3) community wastewater treatment system (CWTS), and (4) onsite vault toilet (OVT). Household effluents consist of excrements and urine released from toilets as well as wastewater released from kitchens and bathrooms. In the present study, household effluents that were discharged from the residential areas having undergone similar treatment methodologies were compared using the umu test, an in vitro bioassay to assess genotoxicity potential. The different treatment methodologies were categorized based upon whether the two kinds of wastewater were mixed or not mixed and treated or not treated. Treated wastewater containing excrements and urine from the OTWTS exhibited the strongest genotoxicity potential compared to other effluents, whereas most of the kitchen and bathroom wastewater from OVT did not display genotoxicity. Data indicated that the genotoxicants in the effluents originated primarily from excrements and urine, and may increase an adverse environmental risk.  相似文献   
4.

Introduction

Malignant pleural mesothelioma (MPM) is an uncommon cancer with a poor prognosis and heterogeneous survival. Surgery for MPM is offered in some specialist centers to highly selected patients. A previously described classification and regression tree (CART) model stratified survival in unselected MPM patients using routinely collected clinical data. This study aimed to examine the performance of this CART model on a highly selected surgical population.

Methods

Data were collected from subjects undergoing cytoreductive surgery for MPM from specialist centers in Hyõgo, Japan, and Sydney, Australia, between 1991 and 2016. The CART model was applied using the combination of clinical variables to stratify subjects into risk groups (1 through 4); survival characteristics were then compared.

Results

Two hundred eighty-nine cases were included (205 from Australia, 84 from Japan). Overall median survival was 34.6 (interquartile range: 17.5–56.1) months; median age was 63.0 (interquartile range: 57.0–67.8) years, and 83.0% (n = 240) were male. There were no clinically meaningful differences between the two cohorts. Survival across the four risk groups was significantly different (p < 0.0001); the model stratified survival well with a Harrell's concordance statistic of 0.62 (95% confidence interval: 0.57–0.66) at 36 months. The group with the longest survival (median, 82.5 months) had: no weight loss, hemoglobin > 153 g/L and serum albumin > 43 g/L at time of referral to the surgical center.

Conclusions

Using routinely available clinical variables, the CART model was able to stratify surgical patients into risk groups with statistically different survival characteristics with fair to good performance. Presence of weight loss, anemia, and low albumin should confer caution when considering surgical therapy for MPM.  相似文献   
5.

Background

A large number of studies have reported the high prevalence of problematic internet use (PIU) among adolescents and students (13-50%)1, and PIU has been associated with many psychiatric symptoms2. In contrast, only a few studies have investigated its prevalence among the adult population. To the best of our knowledge, there have been no studies investigating the prevalence and comorbidity of PIU in a psychiatric population although psychiatric symptoms might either induce PIU in patients with psychiatric illnesses, or PIU might induce or aggravate psychiatric symptoms. The aims of this study are to investigate the prevalence of PIU and psychiatric co-morbidity among adult psychiatric patients.

Methods

Three hundred thirty-three adult psychiatric patients with internet access were recruited at the outpatient clinic of psychiatry at the University Hospital, Kyoto Prefectural University of Medicine over a three-month period. Two hundred thirty-one of them completed the survey (response rate: 69.4%; Male/Female/Transgender: 90/139/2; mean age = 42.2). We divided participants into “normal internet users” and “problematic internet users” using a combination of Young’s Internet Addiction Test (IAT) and the Compulsive Internet Use Scale (CIUS), using established cut-off values. Demographic data and comorbid psychiatric symptoms were compared between the two groups, using self-rating scales measuring insomnia (Athens Insomnia Scale, AIS), depression (Beck Depression Inventory, BDI), anxiety (State-trait Anxiety Inventory, STAI), attention deficit hyperactivity disorder (ADHD) (Adult ADHD Self-report Scale, ASRS), autism (Autism Spectrum Quotient, AQ), obsessive-compulsive disorder (OCD) (Obsessive-Compulsive Inventory, OCI), social anxiety disorder (SAD) (Liebowitz Social Anxiety Scale, LSAS), alcohol abuse, and impulsivity (Barratt Impulsive Scale, BIS).

Results

Of our 231 respondents, 58 (25.1%) were defined as problematic internet users, as they scored high on either the IAT (40 or more) or CIUS (21 or more). The age of problematic internet users was significantly lower than that of normal internet users (35.9 vs 43.6, p<0.001, Mann-Whitney U test). The problematic internet users scored significantly higher on scales measuring sleep problems (AIS, 8.8 for problematic internet users vs 6.3 for normal internet users, p<0.001), depression (BDI, 27.4 vs 18.3, p<0.001), trait anxiety (STAI, 61.8 vs 53.9, p<0.001), ADHD (ASRS, part A 3.1 vs 1.8 and part B 3.5 vs 1.8, p<0.001), autism (AQ, 25.9 vs 21.6, p<0.001), OCD (OCI, 63.2 vs 36.3, p<0.001), SAD (LSAS, 71.4 vs 54.0, p<0.001), and impulsivity (BIS, 67.4 vs 63.5, p=0.004).

Conclusions

The prevalence of PIU among adult psychiatric patients is relatively high (25%). As previous studies reported in the general population, PIU among adult psychiatric patients was associated with lower age and higher psychiatric comorbidity. Longitudinal research is needed to determine any causal relations between problematic internet use and psychopathological illnesses.  相似文献   
6.
Journal of Natural Medicines - A new amide, named dehydropropylpantothenamide (1), was obtained by a co-culture of Nocardia tenerifensis IFM 10554T in the presence of the mouse macrophage-like cell...  相似文献   
7.
Journal of Artificial Organs - The aim was to elucidate the differences in activities of daily living (ADL) after hip arthroplasty among hip resurfacing (HRA), anterolateral total hip arthroplasty...  相似文献   
8.
Journal of Artificial Organs - Thoracic endovascular aortic repair (TEVAR) is expected to be minimally invasive, especially in older patients. However, clinical results of TEVAR in octogenarians...  相似文献   
9.
Journal of Artificial Organs - Left ventricular assist device is an established therapeutic option for the patient with end-stage heart failure. Recently, durable continuous-flow devices have...  相似文献   
10.
Journal of Artificial Organs - In this study, we aimed to determine the electrophysiological efficacy, safety, and electrical stability of a chronically implanted electrode for suprachoroidal...  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