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   472篇
  免费   16篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   5篇
妇产科学   2篇
基础医学   23篇
临床医学   35篇
内科学   112篇
皮肤病学   1篇
神经病学   35篇
特种医学   158篇
外科学   36篇
综合类   2篇
预防医学   47篇
眼科学   1篇
药学   17篇
中国医学   1篇
肿瘤学   16篇
  2022年   4篇
  2021年   7篇
  2020年   5篇
  2019年   6篇
  2018年   7篇
  2017年   4篇
  2016年   9篇
  2015年   10篇
  2014年   5篇
  2013年   8篇
  2012年   7篇
  2011年   6篇
  2010年   7篇
  2009年   4篇
  2008年   9篇
  2007年   8篇
  2006年   7篇
  2005年   7篇
  2003年   5篇
  2002年   5篇
  1999年   4篇
  1993年   3篇
  1992年   9篇
  1991年   19篇
  1990年   23篇
  1989年   40篇
  1988年   35篇
  1987年   33篇
  1986年   32篇
  1985年   37篇
  1984年   17篇
  1983年   17篇
  1982年   4篇
  1981年   4篇
  1980年   3篇
  1979年   7篇
  1978年   4篇
  1977年   6篇
  1974年   4篇
  1973年   2篇
  1972年   6篇
  1971年   11篇
  1970年   5篇
  1969年   3篇
  1968年   5篇
  1967年   5篇
  1966年   2篇
  1965年   6篇
  1964年   3篇
  1963年   2篇
排序方式: 共有492条查询结果,搜索用时 15 毫秒
41.
42.
Background and Aim:  Capsule endoscopy (CE) is widely used for diagnosing small intestinal diseases. In some cases, however, observation of target sites is very poor during CE because of residues etc. Herein we report the usefulness of a preparation comprised of polyethylene glycol solution (PEG) for CE.
Methods:  This was a prospective, randomized, and single-blind study. Forty subjects, fasted for 12 h before CE, were randomized into two groups: 20 subjects in Group A were fasted only, whereas 20 in Group B received 1 liter (L) PEG with 200 mg dimethylpolysiloxane 3 h before CE. For evaluation, the observation period of the small intestine was divided into first and second halves. Subsequently, four investigators, blinded as to which group received the preparation, assessed the condition of the intestine using four rating scales in terms of 'residue' and 'intraluminal gas bubbles'. The effects of the preparation were statistically compared.
Results:  CE images were better in Group B than in Group A with respect to 'intraluminal gas bubbles' ( P  = 0.0038) in the first half of the observation period, as well as residue ( P  = 0.0087) and intraluminal gas bubbles ( P  = 0.0011) in the second half.
Conclusion:  Bowel preparation using 1 L PEG with dimethylpolysiloxane 3 h before CE significantly reduced residue and intraluminal gas bubbles, and was considered to be a useful method for CE.  相似文献   
43.
A 52-year-old woman developed subarachnoid hemorrhage (SAH) caused by a ruptured right internal carotid artery (ICA) aneurysm. Because of the aneurysm configuration, the authors decided to delay surgery and instead undertook serial imaging studies of the aneurysm. The patient remained alert but developed acute bilateral deafness on Day 7. Audiological examination and auditory brainstem responses suggested that the hearing disturbance was cortical in origin. Three-dimensional computed tomography (CT) angiography showed severe vasospasm in the right middle cerebral artery (MCA) and moderate vasospasm in the left ICA and MCA. Three-tesla magnetic resonance (MR) imaging was performed 2 days after the onset of symptoms. Diffusion-weighted and T2-weighted MR images showed an acute infarction in the right insular cortex caused by vasospasm. Perfusion-weighted MR imaging, particularly mean transit time mapping, revealed hypoperfusion in both temporal lobes including the auditory cortex and right auditory radiation. The vasospasm was treated with induction of mild hypertension and hypervolemia. Follow-up MR images, 3D CT angiograms, and audiometry performed 2 weeks after the first examination showed recovery of vasospasm and resolution of perfusion abnormality and hearing disturbance. On Day 26, the aneurysm was successfully occluded with clips and the patient was discharged with no deficits. To the authors' knowledge, this is the first reported case of reversible cortical auditory dysfunction purely due to bilateral cerebral vasospasm detected using perfusion MR imaging after SAH.  相似文献   
44.
45.
Left ventricular hypertrophy (LVH), which is a strong predictor of mortality in patients with endstage renal disease, is present in over 70% of patients commencing dialysis. However, only a few studies on LVH are available in patients before the start of dialysis treatment. The purpose of this study was to evaluate the prevalence and clinical correlates of LVH in patients with advanced stages of chronic kidney disease(CKD). We performed a cross sectional study of 90 patients who had renal diseases but no history of either cardiovascular diseases or arrhythmia. Circulating levels of human atrial natriuretic peptide (hANP) were also measured. LVH was present in 40.0% of the study population. The prevalence of LVH tended to increase with progression of renal decline: 22.7% in stage 3, 43.6% in stage 4, and 48.3% in stage 5 (creatinine clearance >10 mL/min) (p = 0.15). Univariate analyses revealed that hANP and albumin were significantly different between the groups with and without LVH. Stepwise logistic regression analysis showed that hANP and albumin were selected as the independent risk factors. These findings suggest that strict control of body fluid and nutrition could prevent the progression of LVH, and as a result, could attenuate the risk of cardiovascular events in CKD.  相似文献   
46.

Objectives

There are not many chances to arthroscopically reassess how graft tunnel malpositions in primary anterior cruciate ligament reconstruction (ACLR) associate with intra-articular degeneration in revision ACLR. This study was aimed to evaluate whether radiographic tunnel position in primary ACLR affect cartilaginous changes and bucket-handle meniscus tears in revision ACLR.

Methods

Thirty-five patients who underwent revision ACLR were recruited; their primary surgeries were single-bundle reconstructions. Tunnel positions were evaluated using the plain radiographs after primary surgery. The sagittal tunnel positions of the femur (FP) and tibia (TP) were determined on the lateral view. The articular cartilage was evaluated arthroscopically at primary and revision surgery using the International Cartilage Repair Society (ICRS) score. A progression of two grades was considered as cartilaginous changes. Meniscal tears were evaluated with an arthroscopic probe. Logistic regression analysis was conducted using the prevalence of cartilaginous changes or bucket-handle meniscus tears as the dependent variable; tunnel parameters were used as the independent variables.

Results

Seven patients (20.0%) had cartilaginous changes and nine patients (25.7%) had bucket-handle tears in the medial meniscus. In logistic regression analysis, %FP [odds ratio (OR): 1.212; P = 0.007] and the cut-off of 60% in the FP (OR: 22.000; P = 0.008) were correlated with cartilaginous changes. %TP (OR: 1.126; P = 0.036) was correlated with the prevalence of bucket-handle meniscus tears.

Conclusions

Anterior femoral tunnel malposition in the femur was associated with the cartilaginous changes, and posterior tibial tunnel malposition with the development of bucket-handle meniscus tears.  相似文献   
47.
Aim: Non‐alcoholic steatohepatitis (NASH) may progress to liver cirrhosis, and NASH patients with liver cirrhosis are at risk of developing hepatocellular carcinoma. Statins, 3‐hydroxy‐3‐methyglutaryl‐coenzyme A reductase inhibitors, are well known to reduce low‐density lipoprotein cholesterol and reduce the incidence of coronary heart disease and other major vascular events by anti‐inflammatory and antifibrotic effects, and antiproliferative properties in colorectal cancers have also been reported. Recently, statins have been reported to improve hepatic steatosis; however, the effect on fibrosis is controversial. Methods: The effects of pitavastatin (one of the strongest statins) were examined using a choline‐deficient L‐amino acid‐defined (CDAA) diet liver fibrosis model. Results: Pitavastatin significantly attenuated increases in serum aspartate aminotransferase, alanine aminotransferase, hepatic steatosis, oxidative stress, pre‐neoplastic lesions (glutathione S‐transferase placental form‐positive lesions), expression of cytokines, such as tumor necrosis factor‐α and transforming growth factor‐β1, and the expression of tissue inhibitor of metalloproteinase‐1, tissue inhibitor of metalloproteinase‐2 and type I procollagen genes followed by attenuating fibrosis of the liver of CDAA‐fed rats. Conclusion: These results indicate that pitavastatin may inhibit steatosis, hepatic fibrosis and carcinogenesis in rat model of NASH.  相似文献   
48.
49.
Enhanced angiotensin II (AngII) action has been implicated in endothelial dysfunction that is characterized as decreased nitric oxide availability. Although endothelial cells have been reported to express AngII type 1 (AT1) receptors, the exact role of AT1 in regulating endothelial NO synthase (eNOS) activity remains unclear. We investigated the possible regulation of eNOS through AT1 in bovine aortic endothelial cells (BAECs) and its functional significance in rat aortic vascular smooth muscle cells (VSMCs). In BAECs infected with adenovirus encoding AT1 and in VSMCs infected with adenovirus encoding eNOS, AngII rapidly stimulated phosphorylation of eNOS at Ser1179. This was accompanied with increased cGMP production. These effects were blocked by an AT1 antagonist. The cGMP production was abolished by a NOS inhibitor as well. To explore the importance of eNOS phosphorylation, VSMCs were also infected with adenovirus encoding S1179A-eNOS. AngII did not stimulate cGMP production in VSMCs expressing S1179A. However, S1179A was able to enhance basal NO production as confirmed with cGMP production and enhanced vasodilator-stimulated phosphoprotein phosphorylation. Interestingly, S1179A prevented the hypertrophic response similar to wild type in VSMCs. From these data, we conclude that the AngII/AT1 system positively couples to eNOS via Ser1179 phosphorylation in ECs and VSMCs if eNOS and AT1 coexist. However, basal level NO production may be sufficient for prevention of AngII-induced hypertrophy by eNOS expression. These data demonstrate a novel molecular mechanism of eNOS regulation and function and thus provide useful information for eNOS gene therapy under endothelial dysfunction.  相似文献   
50.

Background

The timing to the first undetectable hepatitis C virus (HCV) RNA level is strongly associated with sustained virologic response in pegylated interferon (Peg-IFN) plus ribavirin combination therapy for patients with chronic hepatitis C (CH-C) with genotype 1. This study was conducted to clarify the impact of drug exposure to Peg-IFN on the timing of HCV RNA negativity in Peg-IFN plus ribavirin combination therapy for CH-C patients with genotype 1.

Methods

A total of 1409 patients treated with Peg-IFN alfa-2b plus ribavirin were enrolled and classified into four categories according to the Peg-IFN dosage. Furthermore, 100 patients were extracted from each Peg-IFN dosage category to adjust for characteristic factors, using the propensity score method.

Results

Peg-IFN exposure was dose-dependently associated with the timing of HCV RNA negativity (p????0.001). The HCV RNA negative rate at week 4 decreased from 12% with a Peg-IFN dose of >1.5???g/kg/week to 1?C3% with a dose of <1.5???g/kg/week (p????0.001), and at week 12 the rate had decreased from 44% with a dose of ??1.2???g/kg/week to 18% with a dose of <1.2???g/kg/week (p?=?0.001). Treatment failure (patients without a 1-log decrease of HCV RNA at week 4 or a 2-log decrease of HCV RNA at week 12, or positive at week 24) was found in 54?C66% of patients given <1.2???g/kg/week (p????0.001), and these patients accounted for 64% of the non-responders.

Conclusions

The timing of HCV RNA negativity depends significantly on the Peg-IFN dose. Reducing the Peg-IFN dose can induce a later virologic response or non-response in HCV genotype 1 patients treated with Peg-IFN plus ribavirin.  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