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   1206篇
  免费   73篇
  国内免费   10篇
耳鼻咽喉   8篇
儿科学   83篇
妇产科学   39篇
基础医学   141篇
口腔科学   22篇
临床医学   99篇
内科学   302篇
皮肤病学   28篇
神经病学   57篇
特种医学   32篇
外科学   102篇
综合类   36篇
预防医学   119篇
眼科学   36篇
药学   100篇
中国医学   11篇
肿瘤学   74篇
  2024年   1篇
  2023年   18篇
  2022年   46篇
  2021年   71篇
  2020年   48篇
  2019年   48篇
  2018年   59篇
  2017年   50篇
  2016年   44篇
  2015年   40篇
  2014年   47篇
  2013年   75篇
  2012年   104篇
  2011年   108篇
  2010年   64篇
  2009年   34篇
  2008年   69篇
  2007年   56篇
  2006年   50篇
  2005年   42篇
  2004年   68篇
  2003年   43篇
  2002年   50篇
  2001年   5篇
  2000年   7篇
  1999年   7篇
  1998年   5篇
  1997年   1篇
  1996年   3篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   2篇
  1987年   2篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1978年   1篇
  1977年   1篇
  1941年   1篇
排序方式: 共有1289条查询结果,搜索用时 15 毫秒
11.
AimTo evaluate the efficacy of an ethanolic Salvadora persica extract in removing the smear layer following a root canal procedure.MethodsSixty extracted, single-rooted human teeth were cleaned, shaped, and divided into four groups. Experimental groups 1 (n = 20) and 2 (n = 20) were irrigated with 1 mg/ml and 5 mg/ml of S. persica, respectively. The positive controls (n = 10) were irrigated with 17% ethylenediaminetetraacetic acid (EDTA), while the negative controls (n = 10) were irrigated with saline. Approximately 5 ml of the irrigating solution was delivered into the root canals for 5 min, and the final rinse was performed with 5 ml of 1% sodium hypochlorite. Scanning electron microscopy was used to evaluate the endodontic smear layer removal at the coronal, middle, and apical thirds of the specimens.ResultsA significant difference in smear layer removal between groups 1 and 2 at the coronal and middle thirds of the canal was observed, and no significant difference was seen between group 2 and the positive control at the coronal third. At the apical third, both concentrations of S. persica had similar effects and were less effective than the positive control in removing the smear layer.ConclusionThe 5 mg/ml S. persica solution was significantly more effective than the 1 mg/ml solution. In addition, the 5 mg/ml S. persica solution was as effective as 17% EDTA in removing the smear layer from the coronal third of the canal wall.  相似文献   
12.
Although Helicobacter pylori have been identified in the liver, the role of Helicobacter sp. in human liver diseases remains unclear. This study explored whether H. pylori were internalized and could persist in hepatocytes. The majority of an inoculum of H. pylori (1 x 10(7) colony forming units) adhered to hepatocytes. Using the gentamicin invasion assay we found that approximately 2% were internalized and persisted following passage for more than 2 months. Electron microscopy confirmed the presence of intracellular Helicobacter. The number of adherent or internalized H. pylori was significantly greater with hepatocytes than with gastric epithelial cells (P < 0.05) and was also dependent on cag pathogenicity island (PAI), VacA, OipA, or BabA status. Transmission electron microscopy was used to confirm adherence and invasion of H. pylori into hepatocytes. Internalization of H. pylori was inhibited by antibodies to beta1-integrin receptors, genistein, and cytochalasin D (P < 0.05) consistent with beta1-integrin acting as a surface receptor with additional requirements for tyrosine kinase phosphorylation and actin polymerization. In summary, H. pylori both adhered to and invaded into hepatocytes in vitro, depending on the virulent factors, and persisted within hepatocytes during subcultures. beta1-integrin is likely a receptor involved in internalization of H. pylori into hepatocytes.  相似文献   
13.
Laparoscopic sleeve gastrectomy (LSG) is gaining popularity as bariatric surgery, a small percentage of subjects regain weight after surgery. This study was designed to evaluate body weight changes over a period of two years after LSG and investigate the role of serotonin in regulating energy balance. This is a prospective cohort study. A total of 92 patients with morbid obesity (64 women and 28 men) underwent LSG. All the participants were subjected to physical examination and detailed medical history. Anthropometric measurements were accomplished pre-operative and post-operatively at a frequency of four times per year for two years follow-up. Laboratory investigations were performed pre-operatively, and one and two years post-operatively. Blood samples were collected in the fasting state; for glucose, lipid profile and hormonal assays. Hormones measured were plasma insulin, leptin, serotonin and ghrelin. Results revealed that 35.7% weight loss occurred after one year. However, there was variability in the individual weight loss curve during the period between the first and second post-operative years. Thus, patients were divided into two groups: group I included 78 patients (84%) who maintained the lost weight, and group II included 14 patients (16.0%) who regained weight within 24?months post-operatively. Correlation with BMI revealed positive correlation with leptin and serotonin, whilst negative correlation with ghrelin in group II patients. Mechanisms of weight loss after LSG are not only attributable to gastric restriction but also to the neurohormonal changes. In addition, serotonin may possibly contribute to the interplay of regulatory systems of energy homeostasis  相似文献   
14.
The World Health Organization designated last year as the International Year of the Nurse and the Midwife. And as we know worldwide, 2020 became an unforgettable year as nurses and midwives everywhere confronted the COVID‐19 pandemic. To be a nurse in 2020 was challenging and heroic, but being a nurse in 2020 in Beirut, Lebanon was so extraordinarily charged with adversity. The country witnessed in a one‐year series of tragedies of epic dimensions – laying a heavy toll on front‐line nurses. We present our stories as eight Lebanese nurses, giving voice to our incredible experiences and our ongoing resilience in the face of these adversities. We served in the emergency department of a Beirut city hospital after a catastrophic explosion occurred in the capital on the 4th of August 2020. We reported for duty during a disaster of immense magnitude and are now coping with the aftermath of trauma. As nurses, we have faced many traumas in our country that has experienced through war and terrorism for decades. Arising from this disaster and challenges of the pandemic, we give policy recommendations that deserve urgent attention in Lebanon and underscore the need for disaster preparation, funding, education and importantly mental health care for nurses and other health professionals with help and support of the international community.  相似文献   
15.
16.
17.
18.
IQGAPs genes play critical role in either induction or suppression of cancer and its progression, however the relationship between Ras genes and these genes are still unclear. In this study, we tried to understand the mechanistic action of IQGAPs genes and its correlation with Ras genes in mouse hepatic cancer model. The genetic expressions of IQGAP1, IQGAP2, IQGAP3, Hras, Kras, Nras, Mras, Caspase3, and BAX were followed in both hepatocellular carcinoma and normal liver cells of Balbc mice. Genotoxic agent diethylnitrosamine (DEN)-induced hepatic cancer model was induced in male mice and recorded the occurrence of hepatocellular carcinoma by morphological and histological changes in the liver. It was observed that mRNA expressions of IQGAP1, Hras, Kras, Nras, Mras, Caspase3, and BAX genes were highly elevated in hepatocellular carcinoma cells when compared with normal liver cells, additionally their expressions increased by concentrating the dose of DEN. While, the expressions of IQGAP2 and IQGAP3 were significantly decreased in hepatocellular carcinoma cells when compared with normal liver cells, as well as their expressions decreased more with increasing the dose of DEN. It was concluded from this study that IQGAP1 has a strong signaling relationship with Ras genes in induction of cancer and it is considered as a key gene for induction or suppression of the hepatocellular carcinoma.  相似文献   
19.
20.
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