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   1194篇
  免费   81篇
  国内免费   9篇
耳鼻咽喉   24篇
儿科学   38篇
妇产科学   34篇
基础医学   106篇
口腔科学   106篇
临床医学   123篇
内科学   284篇
皮肤病学   13篇
神经病学   57篇
特种医学   96篇
外科学   192篇
综合类   15篇
预防医学   25篇
眼科学   85篇
药学   31篇
中国医学   1篇
肿瘤学   54篇
  2024年   1篇
  2023年   8篇
  2022年   20篇
  2021年   21篇
  2020年   23篇
  2019年   33篇
  2018年   54篇
  2017年   28篇
  2016年   43篇
  2015年   62篇
  2014年   62篇
  2013年   64篇
  2012年   80篇
  2011年   76篇
  2010年   55篇
  2009年   42篇
  2008年   70篇
  2007年   81篇
  2006年   86篇
  2005年   79篇
  2004年   65篇
  2003年   47篇
  2002年   51篇
  2001年   22篇
  2000年   29篇
  1999年   33篇
  1998年   3篇
  1997年   2篇
  1996年   4篇
  1995年   6篇
  1994年   1篇
  1993年   5篇
  1992年   5篇
  1991年   9篇
  1989年   5篇
  1988年   1篇
  1987年   3篇
  1984年   1篇
  1983年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有1284条查询结果,搜索用时 15 毫秒
51.
Inflammatory myofibroblastic tumor (IMT) is an uncommon solid tumor that was originally described in the lung. A 4‐year‐old girl was admitted to hospital with urticarial rash. On chest radiographs, an opacity was seen in the inferior zone of the left lung, and computed tomography showed a mass in the left lower lobe. Left lower sleeve lobectomy was performed, and the diagnosis was confirmed as IMT. Sleeve resection is the best option in lesions located in the mainstem bronchus or secondary carina. Herein, we present a rare case of IMT of the lung that was successfully treated with sleeve lobectomy. There have been fewer than 15 childhood cases of IMT reported in the literature, and the present 4‐year‐old patient is one of the youngest.  相似文献   
52.

Objectives:

To investigate whether electrolyte levels measured by using blood gas analyzers (ABG) and auto-analyzers (AA) are equivalent and can be used interchangeably.

Methods:

This observational prospective study was conducted in 100 patients admitted to the Intensive Care Unit, Adnan Menderes University School of Medicine, Aydin, Turkey, between March and August 2014. Samples for both AA and ABG analyzers were collected simultaneously from invasive arterial catheters of patients. The electrolyte levels were measured by using 2 methods.

Results:

The mean sodium level measured by ABG was 136.1±6.3 mmol/L and 137.8±5.4 mmol/L for AA (p=0.001). The Pearson’s correlation coefficient was 0.561 (p<0.001). The Bland-Altman 95% limits of agreement were -9.4 to 12.6 mmol/L. The mean potassium levels measured by ABG was 3.4±0.7 mmol/L and AA was 3.8±0.7 mmol/L (p=0.001). The Bland-Altman comparison limits were -0.58 to 1.24 and the associated Pearson’s correlation coefficient was 0.812 (p<0.001).

Conclusion:

The results of the 2 analyzing methods, in terms of sodium, were not equivalent and could not be used interchangeably. However, according to the statistical analyses results, by including, but not blindly trusting these findings, urgent and vital decisions could be made by the potassium levels obtained from the BGA, but a simultaneous follow-up sample had to be sent to the central laboratory for confirmation.Electrolytes are very important for the continuation of the physiological functions of the human body. They play vital roles in: regulation of the cell membrane potential, steady process of neurohormonal pathways, energy transformation and the fluid, and acid-base balance in the body. Signs and symptoms of electrolyte disorders may be nonspecific in an intensive care unit (ICU) patient.1-3 The therapies directed for maintaining vital organ functions affect the electrolyte balance. Consequently, electrolyte disorders are more common in critically ill patients than non-critically ill patients.1 The incidence of electrolyte disorders is nearly 25% in ICU patients.2 In recent studies,4-6 it is shown that in ICU patients, serum sodium and potassium levels are significant predictors of mortality. Therefore, prompt and complete correction of electrolyte disorders in ICU patients is vitally important. Under these circumstances, the importance of obtaining the results of serum electrolyte levels at the earliest is obvious. In routine application, serum electrolytes are measured by the indirect ion-sensing (ISE) method using auto-analyzers (AA) located in the central laboratories of hospitals. In this analyzing method, the processing time is longer because of a delay in the transportation of the samples to the central laboratory on account of several reasons.7 Hence, point-of-care (POC) testing methods, such as, arterial blood gas (ABG) analyzers have been increasingly used in the daily assessments of ICU patients. Blood gas analyzers; use the direct ISE method with short processing time that provides time and rapidity to the physician in the patient’s treatment decisions.7,8 The United States Clinical Laboratory Improvement Amendments (US CLIA) accepts a 0.5 mmol/l difference in the measured potassium levels and a 4 mmol/l difference in the measured sodium levels, in the gold standard measure of the standard calibration solution.9 In some recent studies, the data revealed the difference in the electrolyte levels between the ABG and AA results.10,11 Furthermore, there are also studies that suggest that there is no significant difference between these measuring methods.12,13 Physicians want to trust the veracity of the ABG results of electrolytes such as sodium and potassium because, by this method, the delay in reaching the results is surpassed, and risks arising from this delay may be reduced. However, the results of the above-mentioned studies are confusing and still a diagnostic challenge for physicians. On account of the hesitation by the physicians, we decided to investigate whether the sodium and potassium levels measured by using ABG and AA were equivalent. We conducted a prospective study comparing the electrolyte level results measured in the arterial blood samples by 2 different methods. We tried to notice all limitations of previous similar studies and designed our study according to these points. Thereby, we aimed to improve the accuracy of our study results.  相似文献   
53.
54.
The aim of this study was to investigate the diagnostic value of serum G protein–coupled oestrogen receptor (GPER) levels and their correlation with semen parameters in men with infertility. The participants were divided into two groups as follows: 76 fertile control men (Group 1) and 77 infertile men (Group 2). Semen analysis, hormonal evaluation, serum GPER level and scrotal ultrasound of the participants were evaluated. Follicle-stimulating hormone and total testosterone levels were not significantly different between the groups (p = .413 and p = .535 respectively). The oestradiol level in Group 1 was significantly lower than that in Group 2 (p < .001). The serum GPER level was found to be significantly higher in Group 1 than that of Group 2 (p < .001). GPER levels were positively correlated with the total sperm count, sperm concentration, motility and morphology in Group 2 (r = 0.303, 0.345, 0.260 and 0.322, respectively, p < .001). In this study, GPER levels were positively correlated with sperm parameters, and it was hypothesised that the decrease in GPER expression might be associated with male infertility by adversely affecting spermatogenesis.  相似文献   
55.

Objective

To evaluate the influence of the type of prosthesis in-hospital mortality in the post-operative period in patients who had valve replacement.

Methods

A cross-sectional data, such as gender, origin, age, etiology, echocardiograph data, the type of surgery performed and the prosthesis used in cases of valve replacement were analyzed retrospectively.

Results

We reviewed 353 charts of patients who underwent valve replacement surgery. The mean age was 41.87±17.9 years. Regarding gender, 52.8% were female. As for the origin, 61.1% came from small cities within the state. Of all patients, 58.5% suffered from rheumatic disease. Assessing the type of prosthesis implanted, 70% held replace by bioprosthesis and 30% metallic. The hospital mortality in this study was 11%, with no significant difference between the types of prosthesis utilized.

Conclusion

The type of implant used had no effect on in-hospital mortality.  相似文献   
56.
57.
58.

Purpose

Hospitalization for acute colonic diverticulitis has become more and more frequent. We studied the changes in the rate of admission and incidence of the disease during the last 25 years.

Methods

We performed a retrospective analysis of all cases treated for acute diverticulitis during 1988–2012 at one hospital serving a defined population in Mid-Norway. The study made a distinction between admission rates and incidence rates. The admission rates defined the total number of cases admitted, while the incidence rates defined the number of new patients hospitalized for acute diverticulitis (first admission). Poisson regression was used to analyse factors associated with diverticulitis incidence rates.

Results

A total of 851 admissions in 650 different patients were identified, with an overall admission rate of 38.5 (CI 35.9 to 41.1) per 100,000 person-years. The admission rate increased from 17.9 (CI 14.1 to 22.3)/100,000 during 1988–1992 to 51.1 (CI 44.8 to 58.0)/100,000 during 2008–2012. Poisson regression analysis showed a significant increase in admission rates with a factor of 2.8 (C.I. 2.2 to 3.5) during 25 years. The overall incidence rate (IRR) of new patients was 29.4 (CI 27.1 to 31.7)/100,000 person-years. IRR increased significantly with a factor of 2.6 (CI 1.96 to 3.34) during 25 years, while IRR for perforations increased even more, by a factor of 3.3 (CI 1.24 to 8.58).

Conclusion

The hospital admission rates as well as incidence rates for acute colonic diverticulitis increased significantly during the 25-year time span.  相似文献   
59.
The use of energy drinks is common among adolescents and young age groups. The purpose of this study was to determine energy drink consumption status in students at the Karadeniz Technical University in Turkey and the factors affecting this. The research was performed at the Karadeniz Technical University among a total of 2001 students attending the Administration Department, the Physical Education Department, the Psychological Counseling and Guidance Department and the Faculty of Medicine. The research data were collected using the supervised questionnaire method. The 53.5 % (n = 1070) of students had never tried energy drinks, 22.5 % (n = 450) had tried them once only, 1.5 % (n = 30) had used them for a time and then gave up, 21.1 % (n = 422) consumed occasionally and 1.4 % (n = 29) regularly. The risks of regular energy drink consuming were male gender [2.4 (1.8–3.2)] [OR (95 %CI)], studying at night [1.6 (1.2–2.2)], having friends consuming energy drinks [3.6 (2.6–5.0)], regular physical activity [1.9 (1.4–2.5)], being an alcohol drinker [2.4 (1.7–3.2)]. This study revealed that almost half of university students had experience of energy drinks and that approximately one-fourth still used them. It will be useful for these factors listed above to be borne in mind in the development of policies aimed at protecting young people from the health impacts of energy drinks.  相似文献   
60.
Cerebral ischemia–reperfusion (I/R) injury is caused by lack of blood supply to the brain. The accumulation of toxic products such as reactive oxygen species (ROS) occurs on reperfusion, when the occlusion is removed. The resulting oxidative stress results in the initiation of pathways leading to necrotic and apoptotic cell death. Tadalafil (TAD) prevents the accumulation of ROS and increases antioxidant cellular protective mechanisms. The aim of this study was to investigate the effect of TAD treatment against short-term global brain I/R injury in rats. The study was carried out on 30 Wistar-albino rats, which were divided into three groups including a control group (n = 10), an I/R group (n = 10) and an I/R + TAD group (n = 10) (2 mg/kg/day for 4 days before ischemia). At the end of the experiment, tissue samples were collected for both biochemical and histopathological analyses. Malondialdehyde was significantly lower in the TAD-administered group (9.06 ± 0.15) than in the I/R group (p < 0.05). However, no significant difference was observed in nitric oxide levels in the TAD-administered group compared to the I/R group. The mean superoxide dismutase level was significantly higher in the I/R–TAD group than the I/R group. There was no statistically significant difference in glutathione peroxidase levels in I/R + TAD group compared to I/R group. Histopathologically, TAD-administered group provided significant morphological improvement compared to the I/R group. We concluded that TAD prevented I/R-induced neurotoxicity as shown by obtained biochemical and histopathological findings.  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