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   401篇
  免费   13篇
  国内免费   3篇
儿科学   4篇
妇产科学   3篇
基础医学   118篇
口腔科学   27篇
临床医学   22篇
内科学   68篇
皮肤病学   3篇
神经病学   50篇
特种医学   7篇
外科学   45篇
综合类   1篇
预防医学   15篇
眼科学   12篇
药学   24篇
中国医学   1篇
肿瘤学   17篇
  2023年   1篇
  2022年   2篇
  2021年   12篇
  2020年   10篇
  2019年   15篇
  2018年   2篇
  2017年   4篇
  2016年   8篇
  2015年   6篇
  2014年   10篇
  2013年   17篇
  2012年   14篇
  2011年   20篇
  2010年   16篇
  2009年   15篇
  2008年   27篇
  2007年   23篇
  2006年   26篇
  2005年   33篇
  2004年   31篇
  2003年   27篇
  2002年   20篇
  2001年   9篇
  2000年   5篇
  1999年   10篇
  1998年   9篇
  1997年   4篇
  1996年   1篇
  1995年   4篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   4篇
  1988年   4篇
  1987年   4篇
  1986年   5篇
  1984年   3篇
  1982年   3篇
  1980年   2篇
  1975年   1篇
  1974年   1篇
  1971年   3篇
  1970年   2篇
排序方式: 共有417条查询结果,搜索用时 15 毫秒
81.
Objective - To investigate whether depression was associated with cardiac status and socio-demographic factors in patients with coronary heart disease (CHD). Methods - The sample consisted of 144 symptomatic patients with CHD. For screening depression the Beck Depression Inventory was administered on the day before elective coronary angiography. Results - Twenty-four per cent of patients had probable depressive disorder, but none of them had been previously identified as suffering from depression, or been treated for depression. Alexithymia and dissatisfaction with life were common in depressed patients. Logistic regression analysis showed that neither the cardiac status nor sociodemographic factors were associated with depression. Conclusion - Depression is a common finding and should be looked for independently of other risk factors in patients with CHD.  相似文献   
82.

Background Context

Depression is associated with greater postoperative disability in patients with lumbar spinal stenosis (LSS). No previous studies have reported the association in a 10-year follow-up.

Purpose

To evaluate the association between preoperative and postoperative depressive symptoms and the surgical outcome among patients with LSS in a 10-year follow-up. In addition, we examined the effects of the depressive burden on the surgical outcome.

Design

A prospective observational follow-up study.

Patient Sample

A total of 102 patients with LSS underwent decompressive surgery, and 72 of the original sample participated in the 10-year follow-up study.

Outcome measures

Self-report measures: the Oswestry Disability Index (ODI) and visual analog scale (VAS).

Methods

Data were collected using a questionnaire that was administered seven times during the study period. Depressive symptoms were measured with the Beck Depressive Inventory (BDI). The depressive burden was calculated by summing the preoperative and all follow-up BDI scores. Statistical analysis included cross-sectional group comparisons and linear mixed models. The authors report no conflicts of interest related to this work.

Results

The high depressive burden group had a poorer outcome for pain, disability, and the walking distance at the 10-year follow-up. In linear mixed models, a higher preoperative BDI score associated with higher disability. Furthermore, higher postoperative BDI scores and the depressive burden were associated with higher disability and pain in the 10-year follow-up.

Conclusions

Patients with LSS with even slightly elevated depressive symptoms have an increased risk of postoperative pain and disability in a 10-year follow-up. To improve the surgical outcome among these patients, screening for depression both preoperatively and during the rehabilitation following surgery is important.  相似文献   
83.
Whereas the developed gut mucosal barrier prevents luminal bacteria from invading the host, bacterial translocation appears to be facilitated in the neonate. The aim of this study was to determine the extent to which bacteria spontaneously translocate from the gut to extraintestinal organs during the neonatal period and to relate translocation to the evolving intestinal flora in the rat. Newborn Sprague-Dawley rats suckled ad libitum and ate regular chow after weaning. A total of 167 rats were killed either immediately or at 1, 9, 14, 21, 26, or 42 days after delivery. Mesenteric lymph nodes (MLN), liver, heart blood, and the terminal ileal loop were harvested under sterile conditions and analyzed for aerobic and facultatively anaerobic bacteria by standard microbiologic procedures. Bacterial translocation to the MLN and liver began soon after birth and peaked during the second week. On day 14, translocation to any organ was present in 85% of rats. All cultures from the liver were sterile after day 26. By contrast, the fall in translocation to the MLN was incomplete, as 50% of pups still had positive MLN on day 42. Blood cultures were positive in three of the 167 rats. The intensity of translocation as determined by the number of organs infected significantly increased with the number of gram-negative enterics and gram-positive cocci in the gut and was negatively correlated with the percentage of lactobacilli from the total measured intestinal flora (P < 0.0001). In conclusion, bacterial translocation from the gut is a physiological and age-dependent phenomenon in the neonatal rat. Translocation appears to be facilitated when intestinal concentrations of gram-negative enterics and gram-positive cocci are high and when the concentration of lactobacilli is low.  相似文献   
84.
Biophysical and genetic evidence suggests that Kv4-KChIP2 heteromeric ion channels are the molecular correlate of the dominating fast component of the cardiac transient outward K+ current (Itof). Since Itof is one of the essential currents contributing to the shape of the cardiac action potential in the rat, ferret, dog, and human heart, an important implication of this concept is that all ventricular cardiac myocytes from these species express members of the Kv4 and the KChIP2 gene family. To test this prediction, we developed a modified protocol for the collection and subsequent multiplex single-cell RT-PCR amplification of RNA from individual cardiomyocytes isolated from defined regions of the rat left ventricle. All cardiomyocytes investigated (n=61) were positive for alpha-MHC and Kv4.2 expression. KChIP2 mRNA could also be detected in the vast majority (approximately 87%) of cardiomyocytes. Nearly all of these myocytes co-expressed all three cardiac splice variants of KChIP2. In a small but distinct fraction of myocytes (13%), however, we failed to detect KChIP2 mRNA. The detection thresholds were similar for all target genes and approached a sensitivity of a few molecules of RNA per cell. Our findings support the hypothesis that Itof is mediated by Kv4-KChIP2 heteromeric ion channels in the great majority of cardiac myocytes. A small subpopulation of cardiomyocytes, however, appears to express KChIP2 mRNA at insignificant levels and may therefore use other accessory subunits to generate Itof.  相似文献   
85.

Background

Osteosarcoma is the most common, non-haematopoietic, primary malignant bone tumour with an incidence of 0.3–0.5 per 100,000. There is some discrepancy in literature concerning the peaks of incidence of osteosarcoma. Some describe only one peak which arises in adolescence, whilst others report a bimodal age distribution with a second peak over the age of 60. In this retrospective study, we evaluated osteosarcoma patients over age 60 treated at our department and reviewed previous studies from the literature.

Patients and methods

Sixty-four patients (40 male, 24 female) with a mean age of 29 years (from 7 to 82) were treated for primary osteosarcomas. At the time of diagnosis, seven patients (two male and five female) were over 60 years of age with a mean follow-up of 46 months after definite diagnosis.

Results

Three out of seven osteosarcomas were primarily radiologically or histologically misdiagnosed, but only one was mistreated with intramedullary nailing at a trauma centre. At last follow-up, two patients had died from the disease, three were alive with disease, and two had no evidence of osteosarcoma.

Conclusions

We did not find an increased incidence of primary osteosarcoma in the elderly; yet, older patients had a higher rate of misdiagnosis due to untypical radiological findings in combination with longer times from the onset of first symptoms to definite diagnosis. In cases of pathological fracture, it is essential to assess whether it is caused by mechanical stress or a primary or secondary tumour before leading into mistreatment, especially in older patients.  相似文献   
86.
Aims: The purpose of the present study was to examine whether the association between depression and the serum high‐density lipoprotein cholesterol (HDL‐C) is modified by symptom duration. Methods: Depressed patients (n = 88) and an age‐ and sex‐matched group of healthy general population controls (n = 88) underwent a Structured Clinical Interview for DSM‐IV (SCID), and depressed participants reported the duration of their symptoms. The serum levels of total cholesterol (TC), HDL‐C, low‐density lipoprotein cholesterol (LDL‐C), triglycerides (TG) and non‐HDL, and the ratios of LDL‐C/HDL and TC/HDL‐C were assessed. Results: Major depressive disorder (MDD) subjects with a long symptom duration (≥3 years) had lower levels of HDL‐C compared with healthy controls or MDD subjects with a symptom duration <3 years. The likelihood for long symptom duration doubled for each 0.5‐mmol/L decrease in HDL‐C levels in regression models adjusted for age, gender, marital status, overweight, symptom severity, alcohol consumption, smoking, physical exercise, medication use, and non‐HDL‐C (P < 0.05). Conclusions: These findings suggest that a low serum HDL‐C level, a risk factor for coronary heart disease, is specifically associated with long‐term depressive symptomatology.  相似文献   
87.

Background  

Previous research has shown an association between preoperative depressive symptoms and a poorer surgery outcome in lumbar spinal stenosis (LSS). It is not known whether depressive symptoms throughout the recovery period are relevant to the outcome of surgery in LSS. In this prospective clinical study the predictive value of preoperative and postoperative depressive symptoms with respect to the surgery outcome is reported.  相似文献   
88.
OBJECTIVE: A reduction of the Ca(2+)-independent transient outward potassium current (I(to)) in epicardial but not in endocardial myocytes of the left ventricle has been observed in cardiac hypertrophy and is thought to contribute to the electrical vulnerability associated with this pathology. METHODS: In the present study we investigated the molecular mechanisms underlying regional alterations in I(to) in hypertrophied hearts of spontaneously hypertensive rats (SHR) using the whole-cell patch-clamp technique, quantitative RT-PCR and heterologous expression of underlying ion channel subunits. RESULTS: I(to) was significantly smaller in epicardial myocytes of SHR than in Wistar-Kyoto (WKY) controls (11.1+/-0.9 pA/pF, n=20 vs. 16.8+/-1.7 pA/pF, n=20, p<0.01), but not different in endocardial myocytes from both groups. Quantitative RT-PCR analysis of the genes encoding I(to) revealed significantly lower levels of Kv4.2 and Kv4.3 mRNA in the epicardial region of SHR rats compared to WKY rats. In contrast, mRNA expression levels of all three splice variants of the beta-subunit KChIP2 were significantly higher in both endo- and epicardial myocytes from SHR than from WKY rats. In parallel, inactivation of I(to), which is negatively modulated by KChIP2, was slowed down in SHR while recovery from inactivation remained unchanged. Heterologous co-expression of increasing amounts of KChIP2b together with a fixed amount of Kv4.2 in Xenopus laevis oocytes revealed a hyperbolic relation of recovery from inactivation and inactivation time constant, demonstrating that KChIP2 preferentially affects inactivation, if its expression level is high. CONCLUSION: These results suggest that downregulation of I(to) in the left ventricle of SHR is mediated by a reduced expression of Kv4.2 and Kv4.3 (but not of KChIP2), whereas the slower inactivation of I(to) can be explained by increased expression levels of KChIP2 in SHR.  相似文献   
89.
90.
Anti-inflammatory substances have previously been suggested to show compensatory elevations in depressed individuals with pronounced inflammatory changes. In order to further clarify these observations, we examined depression-related alterations in the serum levels of anti-inflammatory markers interleukin (IL)-1 receptor antagonist (RA) and IL-10 and the pro-inflammatory marker IL-6 in 416 general population participants. Depression was evaluated with the Beck Depression Inventory (BDI). Participants with elevated depressive symptoms (BDI > 14, n = 44) had increased levels of IL-1 RA and IL-6. No changes were observed in their IL-10 levels. In multivariate modeling with adjustments for age, gender, obesity, regular smoking, alcohol use, metabolic syndrome, physical exercise, sleep disturbance, and the use of non-steroidal anti-inflammatory drugs, a high level of IL-1 RA was associated with an increased likelihood of belonging to the group with elevated depressive symptoms (OR for each 1 SD increase in the serum level of IL-1 RA: 2.17, 95% CI 1.35–3.48, p = 0.001). The significance of IL-6 alterations did not persist in the same model. The pronounced secretion of anti-inflammatory marker IL-1 RA may reflect the presence of compensatory mechanisms during a depression-related inflammatory state.  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