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   3673篇
  免费   244篇
  国内免费   26篇
耳鼻咽喉   49篇
儿科学   58篇
妇产科学   99篇
基础医学   449篇
口腔科学   95篇
临床医学   322篇
内科学   1006篇
皮肤病学   77篇
神经病学   346篇
特种医学   110篇
外科学   475篇
综合类   9篇
预防医学   139篇
眼科学   123篇
药学   249篇
中国医学   2篇
肿瘤学   335篇
  2023年   53篇
  2022年   97篇
  2021年   152篇
  2020年   76篇
  2019年   115篇
  2018年   128篇
  2017年   102篇
  2016年   101篇
  2015年   105篇
  2014年   127篇
  2013年   191篇
  2012年   287篇
  2011年   262篇
  2010年   159篇
  2009年   150篇
  2008年   212篇
  2007年   163篇
  2006年   196篇
  2005年   168篇
  2004年   144篇
  2003年   129篇
  2002年   120篇
  2001年   53篇
  2000年   55篇
  1999年   42篇
  1998年   31篇
  1997年   31篇
  1996年   25篇
  1995年   24篇
  1994年   26篇
  1993年   19篇
  1992年   32篇
  1991年   29篇
  1990年   31篇
  1989年   39篇
  1988年   24篇
  1987年   25篇
  1986年   23篇
  1985年   20篇
  1984年   19篇
  1983年   20篇
  1982年   12篇
  1981年   13篇
  1980年   13篇
  1979年   12篇
  1978年   10篇
  1976年   9篇
  1975年   8篇
  1974年   9篇
  1971年   8篇
排序方式: 共有3943条查询结果,搜索用时 15 毫秒
71.
Nabiximols (Sativex) is an oromucosal spray, containing delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD), used as treatment for unresponsive spasticity in multiple sclerosis (MS) patients. Sativex is thought to not affect cognition or induce any psychiatric problem at the doses generally used. Nonetheless, it is known that the concomitant use of more than one muscle-relaxant drugs can result in additive neuropsychiatric effects. Herein we describe a case of a woman affected by MS and treated with baclofen and methylprednisolone, who developed important behavioral changes, including suicidal ideation, after 4 weeks of Sativex administration. We are not completely able to state if Sativex alone was responsible for our patient’s psychiatric symptoms, in reason of the concomitant use of the other drugs.In conclusion, physicians should pay more attention when prescribing drugs to MS patients affected by spasticity, including Sativex, since neurobehavioral side effects may emerge especially in predisposed individuals.  相似文献   
72.
Abstract

Objective: The Unified Classification System (UCS) presents itself as an evolution of the Vancouver Classification (VCS) for the evaluation of periprosthetic fractures of the proximal femur (PPF). The aim of our study was to highlight any loss of reproducibility or validity of the new classification system, compared to the previous one.

Material and methods: We tested the interobserver and intraobserver agreement using 40 PPF clinical cases. Each classifying subtype of the UCS and VCS was present in at least two cases. Six experienced hip surgeons (Senior Surgeon, SS) and 5 surgeons in training (Junior Surgeon, JS) classified the clinical cases, using VCS and UCS. The validity of both classifications was then tested with intraoperative surveys.

Results: The mean κ value for interobserver agreement for the VCS in the JS group was 0.65 and 0.81 for the SS group. The mean κ value for interobserver agreement for the UCS in the JS group was 0.63 and 0.65 for the SS group. The mean κ value for intraobserver agreement for the VCS in the JS group was 0.71 and 0.73 for the SS group. The mean κ value for intraobserver agreement for the UCS in the JS group was 0.72 and 0.7 for the SS group. Validity analysis showed a moderate agreement for the VCS and a good agreement for the UCS.

Conclusion: The UCS completes the Vancouver classification, expanding it. It is reliable, despite the increase in classification categories and number of parameters to evaluate, with a slightly higher validity.  相似文献   
73.
74.
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. In recent years, many disease-modifying therapies (DMT) have been approved for MS treatment. For this reason, a profound knowledge of the characteristics and indications of the available compounds is required to tailor the therapeutic strategy to the individual patient characteristics. This should include the mechanism of action and pharmacokinetic of the drug, the safety and efficacy profile provided by clinical trials, as well as the understanding of possible side effects. Moreover, the evolving knowledge of the disease is paving the way to new and innovative therapeutic approaches, as well as the development of new biomarkers to monitor the therapeutic response and to guide the clinician's therapeutic choices. In this review we provide a comprehensive overview on currently approved therapies in MS and the emerging evidence-based strategies to adopt for initiating, monitoring, and eventually adapting a therapeutic regimen with DMT.  相似文献   
75.
Toxocara spp. infection and the seroconversion rate in the Amazon have been poorly investigated. This study analyzed individual and household-level risk factors for the presence of IgG antibodies to Toxocara spp. in urban Amazonian children over a period of 7 years and evaluated the seroconversion rates over a 1-year follow-up. In children < 59 months of age, the overall prevalence rate was 28.08% in 2003 and 23.35% in 2010. The 2010–2011 seroconversion rates were 13.90% for children 6–59 months of age and 12.30% for children 84–143 months of age. Multilevel logistic regression analysis identified child age, previous wheezing, and current infection with hookworm as significant associated factors for Toxocara spp. seropositivity in 2003. In 2010, age, previous helminthiasis, and having a dog were associated with seropositivity, whereas having piped water inside the household was a protective factor. Control programs mainly need to target at-risk children, water quality control, and animal deworming strategies.  相似文献   
76.
Heartburn is the most specific symptom of gastroesophageal reflux disease (GERD). In clinical practice, heartburn relief by a proton pump inhibitor (PPI) trial does suffice to confirm GERD. However, an objective diagnosis of GERD is required before anti-reflux endoscopic or surgical interventions, independently from PPI response. Thus, since normal findings at upper endoscopy are detected in the majority of patients with heartburn, reflux monitoring is often required. When traditional catheter-based or wireless pH tests are used, reflux episodes are conventionally identified by pH drops below 4.0 units. Combined impedance-pH monitoring has the advantage to provide a comprehensive assessment of both physical and chemical properties of refluxate and the distinction between acid and weakly acidic refluxes, both proven to cause heartburn. Unfortunately, the conventional impedance-pH parameters, namely acid exposure time and number of reflux events, are characterized by suboptimal diagnostic sensitivity, and the reliability of symptom–reflux association indexes remains questionable. Therefore, novel impedance parameters, namely the post-reflux swallow-induced peristaltic wave (PSPW) index and the mean nocturnal baseline impedance (MNBI), have recently been proposed in order to achieve a better diagnostic yield. In fact, they proved to be highly accurate in distinguishing reflux-related from reflux-unrelated heartburn, off- as well as on-PPI therapy. Currently, manual review of impedance-pH tracings is needed because of the modest accuracy of available software tools for automated analysis. PSPW index and MNBI are highly applicable and reproducible, and their calculation requires a few additional minutes during the manual review of impedance-pH tracings. So far, we believe that PSPW index and MNBI are ready for prime time and should become part of the standard analysis of impedance-pH tracings for GERD diagnosis in patients with endoscopy-negative heartburn.  相似文献   
77.
78.
OBJECTIVES: The aim of this study was to assess the potential value of hand-carried ultrasound (HCU) devices in the diagnosis and follow-up of patients with pleural effusion (PE) after cardiac surgery. METHODS: Seventy consecutive patients were evaluated at bedside early after cardiac surgery, in the upright sitting position, using an HCU device on hospital admission and every 3 days until hospital discharge. The posterior chest wall was scanned along the paravertebral, scapular, and posterior axillary lines. For each hemithorax, an effusion index was derived as the sum of the intercostal spaces between the lower and upper limits of the PE along the lines of scanning, divided by 3. A standard chest radiograph was performed in all patients on hospital admission and at hospital discharge, and was qualitatively scored (0, absent; 1, small; 2, large PE). The findings of the HCU device and radiograph were compared using kappa statistics and the Kruskal-Wallis test. RESULTS: A chest ultrasound was feasible in all patients (mean [+/- SD] time, 5 +/- 2 min). Compared with the chest ultrasound, a physical examination showed a sensitivity of 69% and a specificity of 77%. On hospital admission, the HCU device detected a PE in 72 of 140 hemithoraxes. Agreement with the finding of the radiograph was 76% (kappa = 0.52). In 15 hemithoraxes, the HCU device revealed a PE that had not been diagnosed using the radiograph. Conversely, in 18 hemithoraxes a PE that had been diagnosed with a radiograph was not confirmed by the HCU device. The correlation between ultrasound and radiographic scores was statistically significant (p < 0.001). At hospital discharge, a PE was present in 31 of 140 hemithoraxes according to the findings of the HCU device, and in 38 of 140 hemithoraxes according to the findings of the radiograph (agreement, 78%; kappa = 0.44). CONCLUSIONS: In patients early after cardiac surgery, HCU devices allow rapid PE detection and improve the clinical diagnosis. Compared to a radiograph, this method offers the unique advantage of the bedside evaluation of patients without the need for radiation exposure.  相似文献   
79.
Abstract: Background/Aims: Hepatitis C virus (HCV) related disease follows a long, benign course and most affected patients have mild disease. Liver biopsy is mandatory to grade and stage the disease. Characteristic, though non-specific, HCV histological lesions such as bile duct damage and steatosis have been singled out but their association with non-histological parameters has not been completely defined. Our aim was to study the relationships among these histological lesions and clinical, biochemical, functional and virological characteristics in a group of Northern Italian patients with chronic hepatitis. Methods: We studied 172 patients with HCV-related chronic hepatitis. Patients were divided into groups on the basis of histology including bile duct damage and steatosis. Clinical, biochemical, functional and virological profiles were related to histological findings. Results: Histological grading and staging of disease increased as the age of patients increased. Steatosis was present in 70% of our patients and was related to a higher degree of fibrosis and to decreased functional activity. The prevalence of bile duct damage was 20%. This lesion was present in older patients with higher staging and impaired liver function. Biochemically it was associated with an increase in aspartate aminotransferase, gammaglutamyltranspeptidase, alkaline phosphatase, and total bilirubin. Conclusions: In the population we studied, HCV chronic hepatitis was predominantly a mild disease. Moreover both steatosis and bile duct damage were also mild. Steatosis was associated with fibrosis and this might influence liver metabolic function. Bile duct lesions were found in older patients with advanced disease showing biochemical evidence of cholestasis. The molecular role HCV might play in the pathogenesis of these histological features should be addressed in further studies.  相似文献   
80.
Leptin is an adipocyte-derived hormone involved in the homeostasis of body composition. An imbalance in leptin regulation has been observed in patients with liver cirrhosis. We aimed to assess serum and ascitic leptin levels in a group of patients with decompensated liver cirrhosis and to evaluate the relationship of these levels with tumor necrosis factor alpha (TNF-alpha). We assessed both serum and ascitic fluid leptin levels in a series of 16 consecutive patients with liver cirrhosis. We calculated the body mass index (BMI) and assessed body fat (BF) of all patients by means of bioelectric impedence analysis. Leptin levels were analyzed in relationship to biochemical indexes, TNF-alpha levels, and body composition. None of the patients had spontaneous bacterial peritonitis. Both serum and ascites leptin levels were correlated with BMI and BF. On average, ascitic fluid leptin levels (13.1 +/- 10.9 ng/ml) were twice as high as serum levels (7.0 +/- 6.4 ng/ml), and the ascitic fluid/serum ratio of leptin was > 1 in all patients. Serum and ascites leptin levels were positively correlated (rS = 0.675, P = 0.009), while no correlation was observed between leptin and TNF-alpha levels, both in serum and in ascites. Serum and ascites TNF-alpha were not correlated. The ascitic fluid leptin levels of cirrhotic patients with sterile ascites are on average two times higher than circulating levels of this hormone. Noteworthily, they correlate significantly with body composition. These findings seem to suggest that in patients with decompensated liver cirrhosis, intraabdominal production of leptin may contribute to the metabolic picture.  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