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   1029篇
  免费   67篇
  国内免费   4篇
耳鼻咽喉   5篇
儿科学   14篇
妇产科学   15篇
基础医学   111篇
口腔科学   17篇
临床医学   71篇
内科学   241篇
皮肤病学   14篇
神经病学   63篇
特种医学   34篇
外科学   129篇
综合类   26篇
一般理论   3篇
预防医学   134篇
眼科学   53篇
药学   80篇
中国医学   4篇
肿瘤学   86篇
  2023年   16篇
  2022年   42篇
  2021年   62篇
  2020年   40篇
  2019年   73篇
  2018年   83篇
  2017年   35篇
  2016年   36篇
  2015年   42篇
  2014年   58篇
  2013年   66篇
  2012年   102篇
  2011年   110篇
  2010年   34篇
  2009年   31篇
  2008年   38篇
  2007年   36篇
  2006年   38篇
  2005年   35篇
  2004年   25篇
  2003年   31篇
  2002年   23篇
  2001年   9篇
  2000年   6篇
  1999年   5篇
  1998年   1篇
  1997年   2篇
  1996年   3篇
  1995年   2篇
  1993年   2篇
  1992年   1篇
  1989年   1篇
  1988年   2篇
  1983年   2篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1975年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有1100条查询结果,搜索用时 78 毫秒
61.

Background

Satisfaction with and adherence to oral anticoagulant treatment are important measures that decrease morbidity and mortality. Higher satisfaction and adherence to warfarin therapy was found to be associated among other factors with good International Normalized Ratio (INR) control.

Objectives

To assess patient satisfaction with and adherence to oral anticoagulant therapy and to identify predictors of the two studied domains.

Methods

A cross-sectional study was conducted at the Cardiothoracic Clinic in Alshaab Teaching Hospital; Khartoum; Sudan during March-April 2015. A representative sample of patients on oral anticoagulant treatment was recruited. Data was collected through face-to-face interview method using oral Anti-Clot Treatment Scale (ATCS) to measure satisfaction and the 4-items Morisky Scale to measure adherence to therapy. Data was processed using SPSS. Logistic regression analysis was performed. P value <0.05 was considered statistically significant.

Results

A total of 93 patients was included, of them 46 were males. Overall, 47 (50.5%) were classified as satisfied with anti-clot treatment. Patients attained secondary and above educational level were approximately 8 times more satisfied with their anti-clot treatment, compared to those educated below this level, [OR 7.9 (2.9–21.7), P < 0.001]. Similarly, patients currently working were found to be approximately 3 times more satisfied with warfarin therapy, compared those who had no jobs, [OR 2.9 (1.1–7.6), P = 0.035]. Overall, 5.4% of the patients were found to be adherent to warfarin therapy. No definite background characteristic variable was found to be associated with adherence to treatment. No association was found between patient satisfaction and adherence to treatment, (P = 0.490).

Conclusions

Ensuring health education on warfarin together with continuous patients motivation are needed, specifically among patients with low educational level. Efficient multidisciplinary effort from all healthcare providers is needed to make warfarin treatment more successful.  相似文献   
62.

Background

The underlying mechanisms sustaining human persistent atrial fibrillation (PsAF) is poorly understood.

Objectives

This study sought to investigate the complexity and distribution of AF drivers in PsAF of varying durations.

Methods

Of 135 consecutive patients with PsAF, 105 patients referred for de novo ablation of PsAF were prospectively recruited. Patients were divided into 3 groups according to AF duration: PsAF presenting in sinus rhythm (AF induced), PsAF <12 months, and PsAF >12 months. Patients wore a 252-electrode vest for body surface mapping. Localized drivers (re-entrant or focal) were identified using phase-mapping algorithms.

Results

In this patient cohort, the most prominent re-entrant driver regions included the pulmonary vein (PV) regions and inferoposterior left atrial wall. Focal drivers were observed in 1 or both PV regions in 75% of patients. Comparing between the 3 groups, with longer AF duration AF complexity increased, reflected by increased number of re-entrant rotations (p < 0.05), number of re-entrant rotations and focal events (p < 0.05), and number of regions harboring re-entrant (p < 0.01) and focal (p < 0.05) drivers. With increased AF duration, a higher proportion of patients had multiple extra-PV driver regions, specifically in the inferoposterior left atrium (p < 0.01), superior right atrium (p < 0.05), and inferior right atrium (p < 0.05). Procedural AF termination was achieved in 70% of patients, but decreased with longer AF duration.

Conclusions

The complexity of AF drivers increases with prolonged AF duration. Re-entrant and focal drivers are predominantly located in the PV antral and adjacent regions. However, with longer AF duration, multiple drivers are distributed at extra-PV sites. AF termination rate declines as patients progress to longstanding PsAF, underscoring the importance of early intervention.  相似文献   
63.

Aim of the study

The study was aimed to investigate the chemical composition and pharmacological basis for traditional use of essential oil of Nepeta cataria L. (Limiaceae) (Nc.Oil) in gastrointestinal and respiratory disorders.

Materials and methods

Chemical analysis was carried out through GC-EIMS, 13C NMR and Kovats Retention Indices while pharmacological study was carried out in isolated tissues preparations.

Results

Four major components; 1,8-cineol (21.00%), α-humulene (14.44%), α-pinene (10.43%) and geranyl acetate (8.21%) were identified among the 27 compounds in Nc.Oil. In isolated rabbit jejunum, Nc.Oil, papaverine and verapamil inhibited spontaneous and high K+(80 mM) precontractions, as well as shifted the Ca++ concentration–response curves (CRCs) to right, indicating calcium channel blocking activity. In isolated guinea-pig trachea, Nc.Oil and papaverine inhibited carbachol (1 μM) and K+ precontractions with similar potency, while verapamil was more potent against K+. Nc.Oil also potentiated isoprenaline inhibitory CRCs, similar to papaverine, indicating papaverine-like PDE inhibitor activity. In isolated guinea-pig atria, Nc.Oil caused cardiodepression at around 25–80 times higher concentrations, similar to papaverine.

Conclusions

These data indicate that Nepeta cataria possesses spasmolytic and myorelaxant activities mediated possibly through dual inhibition of calcium channels and PDE, which may explain its traditional use in colic, diarrhea, cough and asthma.  相似文献   
64.
We characterize the associations of total cerebral small vessel disease (SVD) burden with brain structure, trajectories of vascular risk factors, and cognitive functions in mid-to-late life. Participants were 623 community-dwelling adults from the Whitehall II Imaging Sub-study with multi-modal MRI (mean age 69.96, SD = 5.18, 79% men). We used linear mixed-effects models to investigate associations of SVD burden with up to 25-year retrospective trajectories of vascular risk and cognitive performance. General linear modelling was used to investigate concurrent associations with grey matter (GM) density and white matter (WM) microstructure, and whether these associations were modified by cognitive status (Montreal Cognitive Asessment [MoCA] scores of < 26 vs. ≥ 26). Severe SVD burden in older age was associated with higher mean arterial pressure throughout midlife (β = 3.36, 95% CI [0.42-6.30]), and faster cognitive decline in letter fluency (β = −0.07, 95% CI [−0.13–−0.01]), and verbal reasoning (β = −0.05, 95% CI [−0.11–−0.001]). Moreover, SVD burden was related to lower GM volumes in 9.7% of total GM, and widespread WM microstructural decline (FWE-corrected p < 0.05). The latter association was most pronounced in individuals who demonstrated cognitive impairments on MoCA (MoCA < 26; F3,608 = 2.14, p = 0.007). These findings highlight the importance of managing midlife vascular health to preserve brain structure and cognitive function in old age.  相似文献   
65.
Wireless Body Area Network (WBAN) consists of low-power, miniaturized, and autonomous wireless sensor nodes that enable physicians to remotely monitor vital signs of patients and provide real-time feedback with medical diagnosis and consultations. It is the most reliable and cheaper way to take care of patients suffering from chronic diseases such as asthma, diabetes and cardiovascular diseases. Some of the most important attributes of WBAN is low-power consumption and delay. This can be achieved by introducing flexible duty cycling techniques on the energy constraint sensor nodes. Stated otherwise, low duty cycle nodes should not receive frequent synchronization and control packets if they have no data to send/receive. In this paper, we introduce a Traffic-adaptive MAC protocol (TaMAC) by taking into account the traffic information of the sensor nodes. The protocol dynamically adjusts the duty cycle of the sensor nodes according to their traffic-patterns, thus solving the idle listening and overhearing problems. The traffic-patterns of all sensor nodes are organized and maintained by the coordinator. The TaMAC protocol is supported by a wakeup radio that is used to accommodate emergency and on-demand events in a reliable manner. The wakeup radio uses a separate control channel along with the data channel and therefore it has considerably low power consumption requirements. Analytical expressions are derived to analyze and compare the performance of the TaMAC protocol with the well-known beacon-enabled IEEE 802.15.4 MAC, WiseMAC, and SMAC protocols. The analytical derivations are further validated by simulation results. It is shown that the TaMAC protocol outperforms all other protocols in terms of power consumption and delay.  相似文献   
66.
With the widespread use of recombinant erythropoietin (EPO) for patients with end-stage renal disease (ESRD), management of iron deficiency is an ongoing issue for the renal team. Effective iron replacement and maintenance play a vital role in efficient use of EPO. For hemodialysis patients, intravenous (i.v.) iron has proven convenient and, as an ancillary drug outside of the composite rate, generates profits for dialysis facilities. Improvements in the vehicle with which i.v. iron is administered have led to a reduction in severe or fatal reactions common with iron dextran products. Oral iron has had a spotty track record as an effective therapy for dialysis patients. Compliance has been hindered by patient discomfort when taking oral iron. Patients on peritoneal dialysis and those with chronic kidney disease remain good candidates for oral iron because of convenience, and oral formulas could prove more effective even in the hemodialysis patient population if they were better tolerated and better absorbed, and if using them would not place an economic burden on the patient and/or an economic hardship on the facility. In a capitated/bundled payment environment, oral iron may become a blessing rather than a curse for facilities that need to find more economic ways of providing services. Heme-iron, now undergoing clinical studies, may be a reliable replacement for i.v. iron in that scenario.  相似文献   
67.
INTRODUCTION: The purpose of this study was to optimize carbon tetrachloride-induced hepatotoxicity in the rat with respect to dose, route of injection, and time course. METHODS: Male Wistar albino rats, 4 to 6 weeks old and weighing 130-180 g were used. Hepatotoxicity was evaluated by measuring the activity of serum enzymes (alkaline phosphatase [ALP], alanine aminotransferase [ALT], and aspartate aminotransferase [AST]) as well as serum total bilirubin level. RESULTS: Intraperitoneal injection of carbon tetrachloride (CCl(4)) increased the activity of ALP (from 64.9 to 137.3 U/l), ALT (from 106.6 to 693.1 U/l), and AST (from 113.8 to 693.9 U/l). Plasma bilirubin level increased (from 0.119 to 0.42 mg/dl). In contrast, subcutaneous injection of CCl(4) had no effect on these variables. The optimum intraperitoneal dose of CCl(4) was found to be 2 ml/kg body weight (dissolved in an equal volume of olive oil), and this increased the level of bilirubin and the activity of the three enzymes significantly, without causing death of the animals. Hepatotoxicity was observed within 2 h of intraperitoneal injection of CCl(4) and reached a peak after 24 h. Bilirubin level and serum enzyme activities declined gradually to normal levels by 3 days after CCl(4) injection. CONCLUSION: It is possible to reliably evoke reversible hepatotoxicity in rats by intraperitoneal injection of 2 ml/kg CCl(4).  相似文献   
68.
In this study 43 patients with idiopathic nephrotic syndrome were randomly distributed into 2 age- and sex-matched groups. The first group was given fluvastatin while the second was used as control. The cases in the 2 groups were evaluated clinically, biochemically (creatinine clearance, albumin, 24-hour proteinuria, and lipogram), neurologically, and histopathologically (examination of renal biopsies obtained basally and after 1 year of treatment with fluvastatin). In the fluvastatin-treated group but not in the control group, we observed a significant reduction in cholesterol, low-density lipoprotein, and triglyceride. Clinical and laboratory assessment showed satisfactory tolerance of the drug by the patients. Proteinuria, serum albumin and creatinine clearance values were significantly better in the statin-treated patients. There was no difference in glomerular sclerosis between the 2 groups while interstitial fibrosis and renal fat deposits were less in the statin-treated group. The reduction in renal fat deposits in the statin-treated group was highly significant, while that of interstitial fibrosis was not. We conclude that: (1) statin can be safely and effectively used in the treatment of dyslipidemia in patients with persistent idiopathic nephrotic syndrome; (2) control of dyslipidemia in nephrotic patients is associated with better control of proteinuria and creatinine clearance; (3) statin treatment may cause regression of renal fat deposits in patients with nephrotic syndrome, and (4) longer term studies are still required to study further possible beneficial effects on renal histology and disease progression.  相似文献   
69.
70.
African trypanosomiasis is characterized by progressive central nervous system (CNS) involvement. Using single and double immunohistochemistry, we evaluated the induction of alpha- and beta-chemokines in brains of Sprague-Dawley rats infected with Trypanosoma brucei brucei (T. b. brucei) and identified their cellular source. The results showed high production of MIP-2, RANTES and MIP-1alpha and to a lower extend MCP-1 in infected animals compared to controls. MIP-2, RANTES and MIP-1alpha were produced early by astrocytes and microglia and later by macrophages and T-cells. These findings suggest that chemokines may contribute to the immunopathogenesis that occurs in the CNS early during infections.  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