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   206篇
  免费   13篇
  国内免费   5篇
儿科学   3篇
基础医学   37篇
口腔科学   2篇
临床医学   19篇
内科学   74篇
皮肤病学   1篇
神经病学   10篇
特种医学   3篇
外科学   29篇
综合类   5篇
预防医学   11篇
药学   16篇
肿瘤学   14篇
  2023年   3篇
  2022年   8篇
  2021年   7篇
  2020年   11篇
  2019年   7篇
  2018年   14篇
  2017年   6篇
  2016年   1篇
  2015年   5篇
  2014年   11篇
  2013年   7篇
  2012年   21篇
  2011年   14篇
  2010年   9篇
  2009年   10篇
  2008年   15篇
  2007年   15篇
  2006年   6篇
  2005年   16篇
  2004年   10篇
  2003年   12篇
  2002年   10篇
  2001年   2篇
  2000年   2篇
  1995年   1篇
  1883年   1篇
排序方式: 共有224条查询结果,搜索用时 15 毫秒
101.
We report a 30-year-old male who had undergone a renal transplant and suffered with secondary hyperparathyroidism. He presented with back pain and minimal neurological deterioration, caused by a thoracic brown tumour. The imaging findings, surgical treatment of the spinal lesion and outcome are discussed. We also discuss primary medical therapy and suggest a rational approach to further imaging of patients in whom brown tumour is suspected.  相似文献   
102.
    
In general, formamidinium lead tri-iodide (FAPbI3) based perovskite solar cells are more stable than their methylammonium lead tri-iodide (MAPbI3) counterparts. However, when it comes to power conversion efficiency (PCE), MAPbI3 solar cells are far better. This work aimed to enhance the power conversion efficiency of FAPbI3 solar cells without compromising their thermal stability. The numerical analysis of 6 different proposed structures with 2 carbon based electron transport materials (C60, PCBM) and 3 copper based hole transport materials (SrCu2O2, CuSCN, CuSbS2) is performed using SCAPS-1D software. The parameters are used from various theoretical and experimental published works. In order to investigate the performance of each proposed structure, the defect density, layer thickness and doping concentration of the absorber layer, electron transport layer (ETL) and hole transport layer (HTL) are varied, and optimized parameters are enumerated. The best simulation result having PCE of 26.48% is achieved with 1.25 V open circuit voltage (VOC), 23.51 mA cm−2 short circuit current (JSC) and 89.5% fill factor (FF) for FTO/PCBM/FAPbI3/SrCu2O2/Au. The proposed structure also showed good thermal stability at 300 K. Moreover, the effects of the different charge transport layer on the energy band alignment, electric field, recombination and IV characteristics are also investigated in detail.

The effect of carbon and copper based charge transport layers on the behavior and performance of FAPbI3 perovskite solar cells was investigated with SrCu2O2/FAPbI3/PCBM structure outperforming others and achieving 26.48% efficiency.  相似文献   
103.
OBJECTIVES: Medical therapy of refractory ulcerative colitis (UC) is associated with long-term side effects of cyclosporine and steroids. Because cyclosporine acts by inhibiting interleukin-2 (IL-2) production, we studied the efficacy and safety of humanized anti-IL2 receptor (CD25) antibodies daclizumab for refractory UC in an open label pilot study. METHODS: Ten patients with chronically active UC received daclizumab, 1 mg/kg i.v. twice with a 4-wk interval. Clinical, endoscopic, and histological evaluation was scored at regular intervals. CD25 immunohistochemistry was followed in mucosal biopsies. The primary study endpoint was clinical improvement at wk 8. RESULTS: Nine of 10 patients completed the study. The median clinical activity score decreased from a median of 8 (95% CI = 7.2-9.2) at baseline to 3.5 (95% CI = 1.4-4.9) at wk 8 (p < 0.005). Endoscopic scores were significantly decreased at wk 8 (wk 0: 8, 95% CI = 6.3-8.5; wk 8: 5.0, 95% CI = 2.6-6.3; p < 0.01). Mucosal biopsies showed a significant decrease in CD25+ cells, and there was a trend toward lower histology scores at wk 8. Quality of life as assessed by the Inflammatory Bowel Disease Questionnaire increased after therapy (baseline: 131, 95% CI = 119-178; wk 8: 169; 95% CI = 124-216, p < 0.05). Nausea was most frequently reported as an adverse event, but always in patients that were concomitantly started on azathioprine. CONCLUSIONS: The anti-IL-2R antibody daclizumab was safe and well tolerated in acute UC. Patients experienced clinical benefit along with signs of endoscopic improvement, but further controlled trials are needed to determine the therapeutic benefit of this compound.  相似文献   
104.
We report 13 cases of Naegleria fowleri primary amebic meningoencephalitis in persons in Karachi, Pakistan, who had no history of aquatic activities. Infection likely occurred through ablution with tap water. An increase in primary amebic meningoencephalitis cases may be attributed to rising temperatures, reduced levels of chlorine in potable water, or deteriorating water distribution systems.  相似文献   
105.
Activation of osteoblastic bone anabolism in the calvarial sutures is considered to be the essential pathologic condition underlying mutant FGFR2-related craniofacial dysostosis. However, early clinical investigations indicated that abnormal cartilage development in the cranial base was rather a primary site of abnormal feature in Apert Syndrome (AS). To examine the significance of cartilaginous growth of the cranial base in AS, we generated a transgenic mouse bearing AS-type mutant Fgfr2IIIc under the control of the Col2a1 promoter-enhancer (Fgfr2IIIc(P253R) mouse). Despite the lacking expression of Fgfr2IIIc(P253R) in osteoblasts, exclusive disruption of chondrocytic differentiation and growth reproduced AS-like acrocephaly accompanied by short anterior cranial base with fusion of the cranial base synchondroses, maxillary hypoplasia and synostosis of the calvarial sutures with no significant abnormalities in the trunk and extremities. Gene expression analyses demonstrated upregulation of p21, Ihh and Mmp-13 accompanied by modest increase in expression of Sox9 and Runx2, indicating acceleration of chondrocytic maturation and hypertrophy in the cranial base of the Fgfr2IIIc(P253R) mice. Furthermore, an acquired affinity and specificity of mutant FGFR2IIIc(P253R) receptor with FGF2 and FGF10 is suggested as a mechanism of activation of FGFR2 signaling selectively in the cranial base. In this report, we strongly suggest that the acrocephalic feature of AS is not alone a result of the coronal suture synostosis, but is a result of the primary disturbance in growth of the cranial base with precocious endochondral ossification.  相似文献   
106.
107.

Background

Student authorship (SA) in research utilizes the H-index (Hi), to measure scholarly impact. We analyzed SA rates over time in the Journal of the American College of Surgeons (JACS).

Methods

We compared Hi of corresponding authors (CA) for articles over time (2006, 2008, 2010, 2012, 2014), comparing those with (SA) and without (nSA) student authors.

Results

SA doubled over time (70–146; P?=?0.02) as did first or second SA rates (21–44; P?=?0.22). Mean and Median CA Hi were similar independent of SA involvement. The change in Hi for CAs in 2006, 2008 and 2010 to current Hi (2016) was similar for SA and nSA groups (2006: 22.4 vs. 20.7; 2008: 20.2 vs. 20.6; 2010: 19.2 vs. 18.3; all P?>?0.05).

Conclusions

The number of SA in JACS publications is increasing, without detriment to CA scholarly advancement. Involving students in surgical research should be encouraged.  相似文献   
108.

Aim

To gain insight into type-2 diabetic patients’ perceptions and beliefs about the use of insulin, to explore barriers to initiation of insulin and to evaluate the impact of a short educational intervention regarding patients’ resistance to using insulin injections.

Subjects and methods

This is an exploratory qualitative study. One-to-one in-depth interviews were conducted with a purposive sample of type-2 diabetic patients. Then, a short educational intervention was conducted with the participants. After the intervention, the participants were interviewed to evaluate their acceptance of insulin initiation. The interviews were audio-taped and transcribed verbatim. Thematic content analysis was conducted and the analysis was reviewed independently by two researchers.

Results

A total of 13 diabetic patients were included in the study. Before the intervention, 11 subjects refused initiation of insulin. Resistance to initiation of insulin was influenced by misconceptions about insulin therapy, psychological barriers and fear, lack of self-efficacy and fear of adverse effects. All subjects perceived that insulin should only be initiated in very severe diabetes. Some participants demonstrated lack of belief in insulin efficacy. Psychological barriers and fears such as fear of self-injection and personal phobia about blood, needle and pain as well as perceived side effects also hindered insulin acceptance.

Conclusion

The study findings revealed that misconceptions about insulin use and psychological barriers played a major role in patients’ resistance to initiation of insulin therapy. The study demonstrated, however, that a short educational intervention could dispel patients’ fears and erroneous beliefs and help them to start insulin therapy.  相似文献   
109.
The aim of this study is to compare the response of interleukin-6 (IL-6) and soluble tumor necrosis factor alpha receptor 1 (s-TNFr1) to two submaximal intensities of exercise in individuals with heart failure (HF). Thirty-two HF individuals aged 45.53 ± 9.41 years, classes II and III of the New York Heart Association (NYHA) classification underwent two sessions of exercise at low and moderate intensities with blood analysis at baseline, exercise and after exercise. The differences were evaluated by Friedman test and factorial ANOVA. Alpha = 5% was considered. No difference in IL-6 was detected for low intensity. At moderate intensity, there was a significant increase after exercise. The s-TNFr1 increased in moderate-intensity exercise and went back to baseline levels after it. A session of moderate-intensity exercise is better than low-intensity exercise at promoting positive immediate inflammatory responses in individuals with HF class II and III of the NYHA.  相似文献   
110.
The effect of Clostridium perfringens α-toxin on production of tumor necrosis factor (TNF)-α and nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells was studied. The pretreatment of wild type α-toxin, but not the inactive mutant, significantly decreased LPS-induced TNF-α and NO production. α-Toxin inhibited the expression of TNF-α and an inducible type of NO synthase protein and mRNA. Furthermore, it inhibited the phosphorylation of IκB-α and p65 NF-κB subunit, and the NF-κB luciferase reporter gene activity in LPS-stimulated cells. The pretreatment of α-toxin increased the level of intracellular ceramide. Taken together, Clostridium perfringens α-toxin pretreatment was suggested to inhibit LPS-induced TNF-α and NO production through the inhibition of NF-κB activation. The relationship between α-toxin-induced intracellular ceramide generation and the NF-κB inhibition is discussed.  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