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   532篇
  免费   33篇
  国内免费   4篇
耳鼻咽喉   4篇
儿科学   59篇
妇产科学   14篇
基础医学   54篇
口腔科学   35篇
临床医学   31篇
内科学   123篇
皮肤病学   10篇
神经病学   53篇
特种医学   13篇
外科学   74篇
综合类   9篇
预防医学   19篇
眼科学   30篇
药学   26篇
肿瘤学   15篇
  2024年   1篇
  2023年   15篇
  2022年   19篇
  2021年   41篇
  2020年   21篇
  2019年   22篇
  2018年   20篇
  2017年   13篇
  2016年   27篇
  2015年   33篇
  2014年   35篇
  2013年   31篇
  2012年   42篇
  2011年   30篇
  2010年   17篇
  2009年   11篇
  2008年   22篇
  2007年   22篇
  2006年   38篇
  2005年   27篇
  2004年   21篇
  2003年   18篇
  2002年   14篇
  2001年   10篇
  2000年   5篇
  1999年   3篇
  1998年   4篇
  1996年   3篇
  1995年   1篇
  1992年   1篇
  1988年   1篇
  1979年   1篇
排序方式: 共有569条查询结果,搜索用时 31 毫秒
71.
AIM: To investigate and compare the cytopathological and clinical effects of amniotic membrane transplantation (AMT) and oral mucosal membrane transplantation (OMMT) in socket contraction. METHODS:Twelve patients who could not be fitted with ocular prosthesis due to socket contracture were included in this study. Seven patients underwent AMT and 5 patients underwent OMMT. Thirteen patients who had healthy sockets were included as control group. Depth of inferior fornix, degree of inflammation, extent of the socket contracture and socket volume were measured in the preoperative period and at sixth and twelfth weeks postoperatively. Impression cytology of conjunctival fornices and tear transforming growth factor beta-1 (TGFβ1) levels were determined. RESULTS:In the AMT group,socket volume and lower fornix depth values were significantly higher (P=0.030 and P=0.004 respectively) and inflammation levels and impression cytology stages (P=0.037 and P=0.022 respectively) were significantly lower in postoperative period compared to preoperative period. In the OMMT group, no statistical differences were found in terms of clinical parameters, inflammation levels and impression cytology stages of preoperative versus postoperative values. Preoperative tear TGFβ1 levels were higher in AMT and OMMT groups compared to the control group (25.5 ng/mL, 26.3 ng/mL and 21.7 ng/mL respectively). Decreased tear TGFβ1 levels were observed in both the AMT and OMMT groups postoperatively (median decrease value=2.1 ng/mL and 2.7 ng/mL respectively). CONCLUSION: AMT is associated with postoperative improvement in inferior fornix depth, socket volume, inflammation and impression cytology levels and may be a more proper alternative method than OMMT in the management of socket contracture.  相似文献   
72.
The transforming growth factor beta 1 (TGFB1) is a regulatory cytokine with both tumor suppressor and tumor-promoting effects in breast cancer (BC) cell lines and tissue. Data about level of circulating TGFB1 and its prognostic significance in BC patients is conflicting. The objective of this study is to determine the clinical significance of the serum TGFB1 levels in BC patients. We enrolled 96 female patients with histopathologically diagnosed BC who did not receive chemotherapy (CT) or radiotherapy. Serum TGFB1 levels were measured by ELISA method and compared with 30 healthy controls. The mean serum TGFB1 level of BC patients was significantly higher than controls (0.08 vs. 0.04 ng/ml, p?<?0.001). There was no significant difference according to known disease-related clinicopathological or laboratory parameters. Serum TGFB1 level had a significant impact on overall survival in both univariate (p?=?0.01) and multivariate analysis (p?=?0.013). Serum TGFB1 level is elevated in BC patients and has a favorable prognostic value. However, it has no predictive role on CT response.  相似文献   
73.
74.
The aim of this study was to determine serum vitamin B12, folic acid and homocysteine (Hcy) levels as well as MTHFR (C677, A1298C) gene polymorphisms in patients with vitiligo, and to compare the results with healthy controls. Forty patients with vitiligo and 40 age and sex matched healthy subjects were studied. Serum vitamin B12 and folate levels were determined by enzyme-linked immunosorbent assay. Plasma Hcy levels and MTHFR polymorphisms were determined by chemiluminescence and real time PCR methods, respectively. Mean serum vitamin B12 and Hcy levels were not significantly different while folic acid levels were significantly lower in the control group. There was no significant relationship between disease activity and vitamin B12, folic acid and homocystein levels. No significant difference in C677T gene polymorphism was detected. Heterozygote A1298C gene polymorphism in the patient group was statistically higher than the control group. There was no significant relationship between MTHFR gene polymorphisms and vitamin B12, folic acid and homocysteine levels. In conclusion, vitamin B12, folate and Hcy levels are not altered in vitiligo and MTHFR gene mutations (C677T and A1298C) do not seem to create susceptibility for vitiligo.  相似文献   
75.
76.
Apigenin (4',5,7-trihydroxyflavone) is one of the leading components supporting targeted treatment options. We explored the cytotoxic and apoptotic effects of various doses of apigenin administered alone and together with 5-fluorouracil (5-FU)-a chemotherapeutic agent with high cytotoxicity-for different incubation periods, on morphologic, DNA, RNA (messenger RNA [mRNA]), and protein levels on the p53 mutant HT29 human colon adenocarcinoma cell line. Treatment with apigenin alone for a 72-hour incubation at 90-μM dose resulted in an apoptotic percentage of 24.92% (P=.001). A higher percentage (29.13%) was observed after treatment with the same dose of apigenin plus 5-FU for the same incubation period (P=.001). These results were confirmed as mRNA and protein expression levels of caspase-3 increased 2.567-fold and mRNA expression levels of caspase-8 increased 3.689-fold compared with the control group. On the other hand, mRNA expression levels of mammalian target of rapamycin (mTOR) and cyclin D1 (CCND1) decreased by 0.423-fold and 0.231-fold, respectively. To our knowledge this is the first study showing that treatment with apigenin alone results in cell cycle arrest through activation of caspase cascade and stimulation of apoptosis in HT29 cells. It also shows that use of apigenin plus 5-FU further increases this effect. This study draws attention to the probable clinical effectiveness of apigenin plus a chemotherapeutic agent with high cytotoxicity. It also highlights the induction of desirable apoptotic effects by targeting the caspase cascade pathway through administration of reduced doses for shorter incubation periods.  相似文献   
77.
78.
79.
Purpose: Following repeated weaning failures in acute care services, spinal cord injury (SCI) patients who require prolonged mechanical ventilation and tracheostomy are discharged to their homes or skilled nursing facilities, with a portable mechanical ventilator (MV) and/or tracheostomy tube (TT) with excess risk of complications, high cost and low quality of life. We hypothesized that many difficult-to-wean patients with cervical SCI can be successfully managed in a rehabilitation clinic. The aim of our study was to develop a respiratory rehabilitation, MV weaning and TT decannulation protocol and to evaluate the effectiveness of this protocol in tetraplegic patients.

Methods: A multidisciplinary and multifaceted protocol, including respiratory assessment and management themes, was developed and performed based on the findings from other studies in the literature. Tetraplegic patients with the diagnosis of difficult-to-wean, who were admitted to the rehabilitation clinic after having been discharged from the intensive care unit to their home with home-type MV and/or TT, were included in this prospective observational study.

Results: The respiratory rehabilitation protocol was applied to 35 tetraplegic patients (10 home-type MV and tracheostomy-dependent, and 25 tracheostomized patients) with C1-C7 ASIA impairment scale grade A, B, and C injuries. Seven out of 10 patients successfully weaned from MV and 30 of 35 patients were decannulated. Four patients were referred for diaphragm pace stimulation and tracheal stenosis surgery. The mean durations of MV weaning and decannulation were 37 and 31 days, respectively.

Conclusions: A multifaceted, multidisciplinary respiratory management program can change the process of care used for difficult-to-wean patients with SCI.

  • Implications for rehabilitation
  • Findings from this study indicate the significance of a multidimensional evaluation of any reversible factors for prolonged MV- and/or TT-dependent SCI patients. Thus, rehabilitation specialists should take this into consideration and should provide the appropriate amount of time to these patients.

  • The proposed protocol of respiratory rehabilitation for MV- and/or TT-dependent SCI patients shows promising results in terms of changing the care used for these patients.

  • Successful implementation of a respiratory rehabilitation and weaning protocol is dependent on careful planning and detailed communication between the rehabilitation specialist and intensivist during the respiratory rehabilitation process.

  • Because many of the so-called difficult- or impossible-to-wean patients were successfully weaned from MV and TT in the PMR clinic, the need for such an outlet for countries without specialized centers is supported.

  相似文献   
80.
Context: Tranexamic acid is commonly used for curing abnormal bleeding in a variety of diseases. In a previous study, 12 different tetrahydro-2H-1,3,5-thiadiazine derivatives were synthesized from the amine group of tranexamic acid. Their antifibrinolytic and antimicrobial activities were compared with tranexamic acid. 3-Methyl-5-(4-carboxycyclohexylmethyl)-tetrahydro-2H-1,3,5-thiadiazine-2-thione (3-MTTT) was the most remarkable one, which may be used as a drug.

Objectives: In vitro genotoxicity of 3-MTTT was investigated using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), micronucleus (MN) and comet assays.

Materials and methods: Various concentrations 0.78, 1.56, 3.13, 6.25, 12.50 and 25.00?μg/mL of 3-MTTT were applied to lymphocytes obtained from two donors for periods of 24 and 48?h. A negative (distilled water), a solvent (2:1 PBS:10% NaOH for cultured lymphocyte, and PBS for isolated lymphocytes) and a positive control (MMC for cultured lymphocytes and H2O2 for isolated lymphocytes) were also maintained.

Results: While this compound did not increase the frequency of abnormal cells and CA/cell ratio compared to negative control (except 48?h, 25?μg/mL), it significantly increased the frequency of SCEs at the four highest concentrations at both treatment periods (except 6.25?μg/mL, 48?h). It significantly decreased the MI in all the concentrations at 24?h (except 0.78?μg/mL) and in the highest three concentrations at 48?h. This compound did not significantly increase the frequency of MN and DNA damage compared to negative control. This compound did not affect the replication and nuclear division index.

Discussion and conclusion: Our results demonstrated that this compound does not represent a significant risk at the genetic level in in vitro human lymphocytes.  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