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   344篇
  免费   22篇
  国内免费   1篇
  2024年   1篇
  2023年   1篇
  2022年   10篇
  2021年   26篇
  2020年   6篇
  2019年   9篇
  2018年   13篇
  2017年   12篇
  2016年   15篇
  2015年   8篇
  2014年   22篇
  2013年   20篇
  2012年   27篇
  2011年   22篇
  2010年   8篇
  2009年   7篇
  2008年   11篇
  2007年   13篇
  2006年   17篇
  2005年   11篇
  2004年   15篇
  2003年   14篇
  2002年   10篇
  2001年   7篇
  2000年   10篇
  1999年   9篇
  1998年   1篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   3篇
  1988年   5篇
  1987年   3篇
  1986年   3篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1978年   2篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
  1973年   2篇
  1962年   1篇
排序方式: 共有367条查询结果,搜索用时 31 毫秒
11.
Barbershops provide areas for the growth and transfer of bacterial pathogens and thereby have an impact on public health. Barbershops are ideal places for the interactive spread of infections, including community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). Here, the work determines the degree of bacterial contamination of hair dryers used in barbershops. The samples were collected in the city of Riyadh, the Kingdom of Saudi Arabia on March 2019. Significant bacterial contamination was seen, with total bacterial count increasing when the hair dryers were run for 20 instead of 10 s. The study shows a high level of bacterial contamination barbershops using hair dryers, with MRSA being isolated in some. The results suggest that high quality filters should be used inside hair dryers and filters, and theses should be cleaned frequently.  相似文献   
12.
13.
Programmed cell death ligand-1 (PD-L1/CD274) is an immunomodulatory molecule involved in cancer and complications of bone marrow transplantation, such as graft rejection and graft-versus-host disease. The present study was designed to assess the dynamic expression of this molecule after hematopoietic stem cell transplantation in relation to acute graft-versus-host disease. Female BALB/c mice were conditioned with busulfan and cyclophosphamide and transplanted with either syngeneic or allogeneic (male C57BL/6 mice) bone marrow and splenic cells. The expression of PD-L1 was evaluated at different time points employing qPCR, western blot and immunohistochemistry. Allogeneic- but not syngeneic-transplanted animals exhibited a marked up-regulation of PD-L1 expression in the muscle and kidney, but not the liver, at days 5 and 7 post transplantation. In mice transplanted with allogeneic bone marrow cells, the enhanced expression of PD-L1 was associated with high serum levels of IFNγ and TNFα at corresponding intervals. Our findings demonstrate that PD-L1 is differently induced and expressed after allogeneic transplantation than it is after syngeneic transplantation, and that it is in favor of target rather than non-target organs at the early stages of acute graft-versus-host disease. This is the first study to correlate the dynamics of PD-L1 at the gene-, protein- and activity levels with the early development of acute graft-versus-host disease. Our results suggest that the higher expression of PD-L1 in the muscle and kidney (non-target tissues) plays a protective role in skeletal muscle during acute graft-versus-host disease.  相似文献   
14.

Background

IUGR increases the risk of type 2 diabetes mellitus (T2DM) in later life, due to reduced insulin sensitivity and impaired adaptation of insulin secretion. In IUGR rats, development of T2DM can be prevented by neonatal administration of the GLP-1 analogue exendin-4. We therefore investigated effects of neonatal exendin-4 administration on insulin action and β-cell mass and function in the IUGR neonate in the sheep, a species with a more developed pancreas at birth.

Methods

Twin IUGR lambs were injected s.c. daily with vehicle (IUGR+Veh, n = 8) or exendin-4 (1 nmol.kg-1, IUGR+Ex-4, n = 8), and singleton control lambs were injected with vehicle (CON, n = 7), from d 1 to 16 of age. Glucose-stimulated insulin secretion and insulin sensitivity were measured in vivo during treatment (d 12–14). Body composition, β-cell mass and in vitro insulin secretion of isolated pancreatic islets were measured at d 16.

Principal Findings

IUGR+Veh did not alter in vivo insulin secretion or insulin sensitivity or β-cell mass, but increased glucose-stimulated insulin secretion in vitro. Exendin-4 treatment of the IUGR lamb impaired glucose tolerance in vivo, reflecting reduced insulin sensitivity, and normalised glucose-stimulated insulin secretion in vitro. Exendin-4 also reduced neonatal growth and visceral fat accumulation in IUGR lambs, known risk factors for later T2DM.

Conclusions

Neonatal exendin-4 induces changes in IUGR lambs that might improve later insulin action. Whether these effects of exendin-4 lead to improved insulin action in adult life after IUGR in the sheep, as in the PR rat, requires further investigation.  相似文献   
15.
16.
This study was carried out to investigate the activation status of unfolded protein response (UPR) in colorectal cancer (CRC) and its contribution to CRC resistance to chemotherapy-induced apoptosis. Chemotherapy-induced apoptosis was assessed by the propidium iodide method. Activation of UPR was evaluated in CRC cell lines using immunoblotting technique and in CRC tissues using immunohistochemistry. Findings of the present study revealed that the UPR is constitutively activated in CRC cell lines and CRC tissues isolated from patients, as evidenced by relatively high levels of the 78-kDa glucose-regulated protein (GRP78) and spliced X-box-binding protein 1 mRNA in tissue samples. In addition, CRC cell lines differentially responded to clinically relevant DNA-targeting agents including cisplatin, and 5-flourouracil. Moreover, the levels of GRP78 were inversely associated with sensitivity of CRC cells to chemotherapy-induced apoptosis. Inhibition of GRP78 by siRNA resulted in increased sensitivity of CRC cells to chemotherapeutic agents. Collectively, current results appear to provide novel insights into the role of UPR in determining sensitivity of CRC cells to chemotherapeutic agents and might have important implications for personalized CRC treatment.  相似文献   
17.
18.
Hemodynamic consequences of rapid changes in posture in humans.   总被引:1,自引:0,他引:1  
Tolerance to +G(z) gravitational stress is reduced when +G(z) stress is preceded by exposure to hypogravity (fraction, 0, or negative G(z)). For example, there is an exaggerated fall in eye-level arterial pressure (ELAP) early on during +G(z) stress (head-up tilt; HUT) when this stress is immediately preceded by -G(z) stress (head-down tilt; HDT). The aims of the present study were to characterize the hemodynamic consequences of brief HDT on subsequent HUT and to test the hypothesis that an elevation in leg vascular conductance induced by -G(z) stress contributes to the exaggerated fall in ELAP. Young healthy subjects (n = 3 men and 4 women) were subjected to 30 s of 30 degrees HUT from a horizontal position and to 30 s of 30 degrees HUT when HUT was immediately preceded by 20 s of -15 degrees HDT. Four bouts of HDT-HUT were alternated between five bouts of HUT in a counterbalanced designed to minimize possible time effects of repeated exposure to gravitational stress. One minute was allowed for recovery between tilts. Brief exposure to HDT elicited an exaggerated fall in ELAP during the first seconds of the subsequent HUT (-17.9 +/- 1.4 mmHg) compared with HUT alone (-12.4 +/- 1.2 mmHg, P <0.05) despite a greater rise in stroke volume (Doppler ultrasound) and cardiac output over this brief time period in the HDT-HUT trials compared with the HUT trials (thereafter stroke volume fell under both conditions). The greater fall in ELAP was associated with an exaggerated increase in leg blood flow (femoral artery Doppler ultrasound) and was therefore largely (70%) attributable to an exaggerated rise in estimated leg vascular conductance, confirming our hypotheses. Thus brief exposure to -G(z) stress leads to an exaggerated fall in ELAP during subsequent HUT, owing to an exaggerated increase in estimated leg vascular conductance.  相似文献   
19.
Ebola virus (EBOV) is a lethal human pathogen with a risk of global spread of its zoonotic infections, and Ebolavirus Zaire specifically has the highest fatality rate amongst other species. There is a need for continuous effort towards having therapies, as a single licensed treatment to neutralize the EBOV is yet to come into reality. This present study virtually screened the MCULE database containing almost 36 million compounds against the structure of a Zaire Ebola viral protein (VP) 35 and a consensus scoring of both MCULE and CLCDDW docking programs remarked five compounds as potential hits. These compounds, with binding energies ranging from –7.9 to –8.9?kcal/mol, were assessed for predictions of their physicochemical and bioactivity properties, as well as absorption, distribution, metabolism, excretion, and toxicity (ADMET) criteria. The results of the 50?ns molecular dynamics simulations showed the presence of dynamic stability between ligand and protein complexes, and the structures remained significantly unchanged at the ligand-binding site throughout the simulation period. Both docking analysis and molecular dynamics simulation studies suggested strong binding affinity towards the receptor cavity and these selected compounds as potential inhibitors against the Zaire Ebola VP 35. With respect to inhibition constant values, bioavailability radar and other physicochemical properties, compound A (MCULE-1018045960-0-1) appeared to be the most promising hit compound. However, the ligand efficiency and ligand efficiency scale need improvement during optimization, and also validation via in vitro and in vivo studies are necessary to finally make a lead compound in treating Ebola virus diseases.

Communicated by Ramaswamy H. Sarma  相似文献   

20.
Oleuropein is one of the most abundant phenolic compounds found in olives. Epidemiological studies have indicated that an increasing intake of olive oil can significantly reduce the risk of breast cancer. However, the potential effect(s) of oleuropein on estrogen receptor (ER)-negative breast cancer is not fully understood. This study aims to understand the anticancer effects and underlying mechanism(s) of oleuropein on ER-negative breast cancer cells in vitro. The effect of oleuropein on the viability of breast cancer cell lines was examined by mitochondrial dye-uptake assay, apoptosis by flow cytometric analysis, nuclear factor-κB (NF-κB) activation by DNA binding/reporter assays and protein expression by Western blot analysis. In the present report, thiazolyl blue tetrazolium bromide assay results indicated that oleuropein inhibited the viability of breast cancer cells, and its effects were more pronounced on MDA-MB-231 as compared with MCF-7 cells. It was further found that oleuropein increased the level of reactive oxygen species and also significantly inhibited cellular migration and invasion. In addition, the activation of NF-κB was abrogated as demonstrated by Western blot analysis, NF-κB-DNA binding, and luciferase assays. Overall, the data indicates that oleuropein can induce substantial apoptosis via modulating NF-κB activation cascade in breast cancer cells.  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