首页 | 官方网站   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   404篇
  免费   29篇
  国内免费   2篇
医药卫生   435篇
  2023年   11篇
  2022年   8篇
  2021年   35篇
  2020年   20篇
  2019年   35篇
  2018年   34篇
  2017年   28篇
  2016年   25篇
  2015年   18篇
  2014年   24篇
  2013年   26篇
  2012年   40篇
  2011年   30篇
  2010年   18篇
  2009年   11篇
  2008年   13篇
  2007年   21篇
  2006年   13篇
  2005年   6篇
  2004年   7篇
  2003年   3篇
  2002年   6篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
排序方式: 共有435条查询结果,搜索用时 687 毫秒
1.
The coronavirus disease 2019 (COVID-19) disease was first detected in December 2019 in Wuhan, China. This disease is currently one of the most important global health problems. The novel coronavirus COVID-19 is a respiratory illness, that has caused a deadly pandemic that is spreading rapidly around the world. It is not only a respiratory system virus that causes severe lung disease, but also a systemic disease agent that can affect all systems. People with COVID-19 disease usually have respiratory signs, however, the liver disorder is not an uncommon presentation. In addition, many studies around the world have revealed that the liver is injured to various degrees in patients with severe acute respiratory syndrome coronavirus 2 disease. This review mainly focuses on the impact of COVID-19 on Liver Injury at various ages.  相似文献   
2.
3.
Toxigenicity, species, and type species of Pasteurella multocida isolates cannot be differentiated by morphology or standard biochemical reactions. A more rapid method is needed for P. multocida detection from clinical cases. These findings provide rapid insights into the characteristics of P. multocida isolates and suggest that this method can identify toxigenic and specific capsular type P. multocida. A PCR assay has been developed for rapid detection of P. multocida and differentiation of capsular types A and D. In this rapid method, kmt1, capA and capD, and toxA genes were amplified and a reliable multiplex PCR method for the detection of P. multocida in sheep and goats in the south of Iran was designed. Twenty isolates were obtained, which evinced characteristic morphological and cultural properties. Ten samples were identified simultaneously through the presence of the kmt1 gene as P. multocida species, the hydD–hydC gene as type A capsule, and the toxA gene as dermonecrotic toxin by mPCR, but none of them belonged to type D.  相似文献   
4.
5.

Aim

To assess the association between obesity and risk of migraine with aura and features of migraine attacks among a population of Iranian adults.

Methods

In this case-control study, 102 confirmed cases of migraine with aura were matched based on age and gender with 102 healthy subjects. Data on demographic characteristics and anthropometric measurements were collected from all cases and controls by the same methods. Overweight and obesity were considered as body mass index ≥25–30?kg/m2 and?≥?30?kg/m2, respectively. Features of migraine attacks including frequency, duration and headache daily result were determined for patients based on international headache society criteria.

Results

Mean age of subjects was 34.5?±?7.4 years and 77.9% of them were female. Compared with subjects with normal body mass index, those with obesity had greater odds for having migraine with aura (OR: 3.06, 95% CI: 1.11–8.43). Such finding was also seen even after adjusting for confounding variables; in a way that subjects with obesity were 2.92 times more likely for having migraine with aura compared with those with normal weight (OR: 2.92, 95% CI: 1.03-8.33). Among migraine with aura patients, we found that those with obesity had higher headache daily result compared with subjects with normal weight. However, obesity was not associated with frequency and duration of migraine attacks.

Conclusions

We found that obesity was positively associated with risk of migraine with aura. In addition, subjects with obesity had higher headache daily result compared with those with normal weight.  相似文献   
6.

Purpose

Ultrasound imaging is an effective approach for diagnosing breast cancer, but it is highly operator-dependent. Recent advances in computer-aided diagnosis have suggested that it can assist physicians in diagnosis. Definition of the region of interest before computer analysis is still needed. Since manual outlining of the tumor contour is tedious and time-consuming for a physician, developing an automatic segmentation method is important for clinical application.

Methods

The present paper represents a novel method to segment breast ultrasound images. It utilizes a combination of region-based active contour and neutrosophic theory to overcome the natural properties of ultrasound images including speckle noise and tissue-related textures. First, due to inherent speckle noise and low contrast of these images, we have utilized a non-local means filter and fuzzy logic method for denoising and image enhancement, respectively. This paper presents an improved weighted region-scalable active contour to segment breast ultrasound images using a new feature derived from neutrosophic theory.

Results

This method has been applied to 36 breast ultrasound images. It generates true-positive and false-positive results, and similarity of 95%, 6%, and 90%, respectively.

Conclusion

The purposed method indicates clear advantages over other conventional methods of active contour segmentation, i.e., region-scalable fitting energy and weighted region-scalable fitting energy.
  相似文献   
7.
Amniotic membrane (AM), the innermost layer of the fetal membrane, is considered as a suitable candidate for cancer therapy. In order to develop the AM as a new cancer therapeutic approach, it is essential to understand the molecular mechanism of the AM anti-cancer properties. Previous studies demonstrated that anti-proliferative effects of the AM on tumor cells were associated with induction of cell cycle arrest. Moreover, it has been shown that unknown substances in the AM induce apoptosis in cancer cells and inhibit angiogenesis in tumors. In contrast to the effects of the AM, heat shock proteins (HSPs), in particular HSP90, play a crucial role in development of tumorgenesis. HSP90 inhibits apoptosis in cancer cells and enhances angiogenesis and cell cycle progression. Based on the opposite effects of the amniotic membrane ingredients and HSP90, we hypothesized here that possible mechanism of the AM anti-cancer effects is through inhibition of HSP90.  相似文献   
8.
Toll-like receptors (TLRs) are known for their essential roles in promotion of innate immunity and induction of adaptive immunity through recognition of pathogen-associated molecular patterns (PAMPs) or danger associated molecular patterns (DAMPs). TLR genes are excellent models for the study of the selective pressure enforced by microorganisms on the host genome. Phylogenetic analyses have shown that interactions between pathogens and immune systems have changed during evolution. Selective pressure for maintenance of specific pathogen recognition has led to evolution of TLRs under both positive and purifying selection. However, intracellular and cell-surface TLRs have been affected differently due to their variation in conservational constraints. In this review, we summarize some of the main studies on the influence of selection on shaping the evolution of several TLR gene families in different terrestrial vertebrate species. We also describe the effect of evolution on the function of different TLRs and their specific conservations in these species and show similarities and differences in evolutionary patterns of TLR orthologs among species as well as among TLR gene families.  相似文献   
9.
Digynic triploidy is classically associated with a severely growth restricted fetus and a small nonmolar placenta. However, in genotyping hydatidiform moles as part of clinical practice, we identified two digynic triploid conceptions presenting with histopathological features of classical complete hydatidiform mole (CHM). Both cases occurred in women with a history of previous molar pregnancies and no normal pregnancies. Pathological review and genotyping of other molar pregnancies in these cases showed them to be typical CHM with negative p57KIP2 immunostaining of the cytotrophoblast cells and villous stroma and to be diploid but biparental, confirming a diagnosis of familial recurrent hydatidiform mole (FRHM). Mutation screening of NLRP7 had identified a homozygous duplication, leading to a truncated protein, in case 1 whereas mutation screening of KHDC3L (C6orf221) in case 2 showed both the proband and her sister to be compound heterozygotes for mutations in KHDC3L. The observation of a single digynic, triploid conception presenting as a CHM in women with FRHM, where other pregnancies are diploid and biparental, supports the hypothesis that the role of both NLRP7 and KHDC3L in pregnancy is in setting and/or maintaining the maternal imprint. Clinically, a diagnosis of FRHM should be considered in women with genetically unusual conceptions that are phenotypically CHM.  相似文献   
10.

Background:

Sarcoidosis is a systemic multi-organ granulomatous disease of unknown etiology that is characterized by the presence of granuloma in various organs. The clinical features of sarcoidosis are heterogeneous but pulmonary involvement is cardinal manifestations. The aim of this study was to determine radiologic, clinical and laboratory findings of patients with sarcoidosis.

Patients and Methods:

In a cross-sectional study, all patients visiting sarcoidosis clinic were enrolled in the study. Computed tomography (CT) scan was obtained and lab exams were obtained from patient and reports were recorded in data sheet.

Results:

Total of 55 patients with sarcoidosis were enrolled in the study. The average of age was 44.6 (range 25-62) years. Thirty-seven patients were male and 18 were female. The most common extra-pulmonary manifestation was arthritis (in 18% of cases) and then lupus pernio (12.8%) and uveitis (10.9%). Bilateral hilar adenopathy and para tracheal lymphadenopathy was observed in 39(70%) and 22 (40%) of patients. Parenchymal nodules (30%), bronchiectasia (25%), ground-glass opacification (18%) were the most common findings. Percentages of patients with dyspnea were 29% and percentages of patients with cough were 21%. Among abnormal lab tests, high urine calcium (Ca) were positive in 21% and high angiotensin-converting enzyme (ACE) in 16% of patients.

Conclusion:

Pulmonary involvements are both fibrosis and granulomatosis and the most common manifestations are parenchymal nodules, bronchiectasia and high-grade fibrosis. The most common extra-pulmonary involvement is arthritis. Lab tests are non-specific and have no correlation with duration or severity of disease.  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-23

京公网安备 11010802026262号