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   343篇
  免费   16篇
  国内免费   2篇
儿科学   2篇
妇产科学   13篇
基础医学   50篇
口腔科学   18篇
临床医学   42篇
内科学   53篇
皮肤病学   3篇
神经病学   42篇
特种医学   10篇
外科学   25篇
综合类   4篇
预防医学   40篇
眼科学   5篇
药学   22篇
中国医学   3篇
肿瘤学   29篇
  2023年   2篇
  2022年   12篇
  2021年   17篇
  2020年   9篇
  2019年   5篇
  2018年   6篇
  2017年   14篇
  2016年   16篇
  2015年   15篇
  2014年   21篇
  2013年   31篇
  2012年   43篇
  2011年   34篇
  2010年   16篇
  2009年   7篇
  2008年   20篇
  2007年   15篇
  2006年   22篇
  2005年   9篇
  2004年   11篇
  2003年   12篇
  2002年   10篇
  2000年   1篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1994年   2篇
  1992年   1篇
  1991年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
排序方式: 共有361条查询结果,搜索用时 31 毫秒
81.

Aim of Study  

This study aims to assess the effectiveness, tolerance, safety, and patient satisfaction of obesity treatments using the Bioenterics intragastric balloon (BIB).  相似文献   
82.
MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression and which have been implicated in cancer. We evaluated whether five candidate predictive miRNAs, derived from a pilot study in which 249 miRNAs were assayed, were associated with clinical benefit of tamoxifen therapy in advanced breast cancer. These five miRNAs were measured in an independent series of 246 estrogen receptor (ER)-positive primary breast tumors of patients who received tamoxifen for advanced disease by quantitative Real Time PCR. Univariate analysis showed that higher expression levels of hsa-miR-30a-3p, hsa-miR-30c, and hsa-miR-182 were significantly associated with benefit of tamoxifen treatment and with longer PFS (all P-values <0.01). In multivariate analysis, corrected for the traditional predictive factors, only hsa-miRNA-30c was an independent predictor (P-value <0.01). Finally, in an attempt to understand the biology connected to this miRNA, Global testing pathway analysis showed an association of hsa-miRNA-30c expression with HER and RAC1 signaling pathways. We identified hsa-miRNA-30c as an independent predictor for clinical benefit of tamoxifen therapy in patients with advanced breast cancer. Assessment of tumor levels and connected pathways could be helpful to improve treatment strategies.  相似文献   
83.
Lumbar puncture was performed on 12 healthy female volunteers at the L4-5 level. CSF concentrations of 5-HIAA, HVA and HMPG were included in turn as dependent variables in repeated analyses of covariance with age, height, tapping-time, atmospheric pressure and the distance on the spine in the lying position as regressors. Use or non-use of oral contraceptives was included as a nominal variable. Results obtained were confirmed by nonparametric statistics. We found significant relationships between 5-HIAA and HVA, respectively, and height when the concentrations per minute of tapping-time (nM/min) were used as dependent variables. Hypothetically, the tapping-time mirrors the transport of concentrated CSF from the cranial to the caudal region when sitting up. We also found significant influences of atmospheric pressure and the use or non-use of oral contraceptives on HMPG. The role of atmospheric pressure is not clear but it might contribute to the transport of HMPG from the periphery to the CSF or affect the outflow of HMPG from the lumbar CSF compartment. The contribution of oral contraceptives might reflect interactions in the cerebral catecholamine metabolism.  相似文献   
84.
85.
AIM: A comparison of the outcome of hepatitis virus-positive and -negative kidney transplant and hemodialysis patients was the aim of this investigation. MATERIALS AND METHODS: The study involved 384 kidney transplant patients (67 HBsAg positive, 39 anti-HCV positive, 278 hepatitis negative), transplanted between 1987 and 2001, and 403 hemodialysis patients (128 HBsAg positive, 83 anti-HCV positive, 192 hepatitis negative) who had started hemodialysis and were referred to the kidney transplant waiting list during the same period. RESULTS: Hemodialysis patients were older than transplant patients. Comparison of the groups' survival rates, adjusted for patient age, showed that all kidney transplant patients survived longer than hemodialysis patients (p < 0.001). HBV infection had a negative impact on patient survival, especially in hemodialysis patients. HCV infection did not have a significant influence on patient survival. Cardiovascular disease was the main cause of death of all hemodialysis- and hepatitis-negative transplant patients. Liver failure was one of the leading causes of death in HBV-positive transplant patients. Mortality risk was higher for older patients, HBV-positive and -negative hemodialysis patients. CONCLUSIONS: Kidney transplantation offers longer survival for hepatitis-positive and -negative hemodialysis patients. HBV but not HCV infection had a negative impact on ESRD patient survival.  相似文献   
86.
The crosslinking of chitosan (CHT) and gelatin (GEL) accomplished with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) was investigated and optimized in relation to hydrogels stability by varying the CHT/GEL mass ratio and the EDC/NHS molar ratio at different and constant EDC concentrations. Hydrogels were also fabricated in the presence of α-tocopherol to assess the release mechanism of a lipophilic drug from a highly-hydrophilic CHT/GEL hydrogel network. Alterations in the physico-chemical properties of hydrogels were characterized by differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR), and their biostability was studied within a simulated body-fluid solution (PBS of pH 7.4) at 37 °C for 24 h by evaluating the degree of swelling, followed by topography and morphology characterization using scanning electron microscopy (SEM). The analysis confirmed the formation of a modulated hydrogels porosity using different freezing temperatures prior to lyophilization. The in vitro degradation behaviors of the hydrogels were investigated for up to 5 weeks using collagenase, lysozyme, and N-acetyl-β-D-glucosaminidase by monitoring the weight-losses of hydrogels and their degradation products, being identified by UV-Vis spectroscopy and high-performance liquid chromatography (HPLC) as well as the pH monitoring of degraded solutions. It was observed that an inner morphological hydrogel structure influences their swelling and degradation behavior, which is additionally reduced by in-gel-embedded α-tocopherol because of hydrophobic interactions with their constituents, and hindering the effect on collagenase activity.  相似文献   
87.
Intestinal DCs orchestrate gut immune homeostasis by dampening proinflammatory T‐cell responses and inducing anti‐inflammatory IgA responses. Although no specific DC subset has been strictly assigned so far to govern IgA response, some candidate subsets emerge. In particular, plasmacytoid DCs (pDCs), which notoriously promote anti‐viral immunity and T‐cell tolerance to innocuous antigens (Ags), contribute to IgA induction in response to intestinal viral infection and promote T‐cell‐independent IgA responses in vitro. Here, using two transgenic mouse models, we show that neither short‐term nor long‐term pDC depletion alters IgA class switch recombination in Peyer's patches and frequency of IgA plasma cells in intestinal mucosa at steady state, even in the absence of T‐cell help. In addition, pDCs are dispensable for induction of intestinal IgA plasma cells in response to oral immunization with T‐cell‐dependent or T‐cell‐independent Ags, and are not required for proliferation and IgA switch of Ag‐specific B cells in GALT. These results show that pDCs are dispensable for noninfectious IgA responses, and suggest that various DC subsets may play redundant roles in the control of intestinal IgA responses.  相似文献   
88.
Several studies have provided evidence that interleukin-15 (IL-15) can enhance protective immune responses against Mycobacterium tuberculosis infection. However, the effects of IL-15 deficiency on the functionality of M. tuberculosis-specific CD4 and CD8 T cells are unknown. In this study, we investigated the generation and maintenance of effector and memory T-cell responses following M. tuberculosis infection of IL-15(-/-) mice. IL-15(-/-) mice had slightly higher bacterial numbers during chronic infection, which were accompanied by an increase in gamma interferon (IFN-gamma)-producing CD4 and CD8 T cells. There was no evidence of increased apoptosis or a defect in proliferation of CD8 effector T cells following M. tuberculosis infection. The induction of cytotoxic and IFN-gamma CD8 T-cell responses was normal in the absence of IL-15 signaling. The infiltration of CD4 and CD8 T cells into the lungs of "immune" IL-15(-/-) mice was delayed in response to M. tuberculosis challenge. These findings demonstrate that efficient effector CD4 and CD8 T cells can be developed following M. tuberculosis infection in the absence of IL-15 but that recall T-cell responses may be impaired.  相似文献   
89.
We previously reported that plasmacytoid dendritic cells (pDCs) infiltrating breast tumors are impaired for their interferon‐α (IFN‐α) production, resulting in local regulatory T cells amplification. We designed our study to decipher molecular mechanisms of such functional defect of tumor‐associated pDC (TApDC) in breast cancer. We demonstrate that besides IFN‐α, the production by Toll‐like receptor (TLR)‐activated healthy pDC of IFN‐β and TNF‐α but not IP‐10/CXCL10 nor MIP1‐α/CCL3 is impaired by the breast tumor environment. Importantly, we identified TGF‐β and TNF‐α as major soluble factors involved in TApDC functional alteration. Indeed, recombinant TGF‐β1 and TNF‐α synergistically blocked IFN‐α production of TLR‐activated pDC, and neutralization of TGF‐β and TNF‐α in tumor‐derived supernatants restored pDCs' IFN‐α production. The involvment of tumor‐derived TGF‐β was further confirmed in situ by the detection of phosphorylated Smad2 in the nuclei of TApDC in breast tumor tissues. Mechanisms of type I IFN inhibition did not involve TLR downregulation but the inhibition of IRF‐7 expression and nuclear translocation in pDC after their exposure to tumor‐derived supernatants or recombinant TGF‐β1 and TNF‐α. Our findings indicate that targeting TApDC to restore their IFN‐α production might be an achievable strategy to induce antitumor immunity in breast cancer by combining TLR7/9‐based immunotherapy with TGF‐β and TNF‐α antagonists.  相似文献   
90.
The genetic profile of Trypanosoma cruzi was evaluated in parasite populations isolated from Beagle dogs experimentally infected with Be-78 and Y strains that present distinct biological and genetic characteristics. Molecular characterization of the isolates obtained 30days and 2years after infection was carried out. For typing MLEE, sequence polymorphisms of the mitochondrial cytochrome oxidase subunit II gene (COII) and RAPD profiles were used. The profiles of MLEE were the same for the parental Be-78 strains as their respective isolates. However, changes of MLEE profile were observed in two T. cruzi isolates from dogs inoculated with Y strain. Changes in the mitochondrial DNA (COII) and RAPD profiles of the Y strain were also observed. The dendogram constructed by UPGMA with RAPD results indicated two major branches. Global data show that the genetic modulation in polyclonal strains during the long-term infection occurred and was strain-dependent. This study still suggests that each host (here each dog) harbors a determinate T. cruzi population that may change or be modulated throughout long-term infection. This might to hinder the observation of correlation between the genetics of T. cruzi and their biological properties and behavior in different host species due to the complexity of the parasite-host interaction in which probably the genetic background of both should be considered.  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