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   741篇
  免费   45篇
  国内免费   1篇
耳鼻咽喉   28篇
儿科学   27篇
妇产科学   45篇
基础医学   89篇
口腔科学   38篇
临床医学   48篇
内科学   130篇
皮肤病学   50篇
神经病学   76篇
特种医学   25篇
外科学   94篇
综合类   4篇
预防医学   31篇
眼科学   39篇
药学   42篇
中国医学   3篇
肿瘤学   18篇
  2023年   5篇
  2022年   7篇
  2021年   26篇
  2020年   16篇
  2019年   16篇
  2018年   26篇
  2017年   35篇
  2016年   44篇
  2015年   30篇
  2014年   36篇
  2013年   46篇
  2012年   60篇
  2011年   64篇
  2010年   40篇
  2009年   38篇
  2008年   68篇
  2007年   66篇
  2006年   42篇
  2005年   47篇
  2004年   27篇
  2003年   22篇
  2002年   16篇
  2001年   1篇
  1999年   1篇
  1998年   2篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1990年   1篇
  1988年   1篇
  1985年   1篇
排序方式: 共有787条查询结果,搜索用时 234 毫秒
1.
2.
Objective: The aim of the present study was to evaluate changes in maternal serum neutrophil gelatinase-associated lipocalin (NGAL) and procalcitonin (PCT) concentrations in preeclampsia.

Material and method: This case–control study consisted of 40 preeclamptic and 40 healthy singleton pregnancies matched for age and body mass index. Serum NGAL and PCT levels were compared between the groups. Diagnostic performance and clinical association of these markers were evaluated.

Results: NGAL and PCT concentrations were significantly higher in preeclamptic group (p?p?=?0.001, respectively) and their levels were correlated with the severity of the preeclampsia. There were significant positive correlation between these markers and mean arterial pressure (MAP) and spot urine protein excretion. There was negative correlation between NGAL and apgar scores and fetal birth weight. Pregnancies with higher NGAL (OR: 4.89; 95% CI: 1.81–13.21) and higher PCT (OR: 6.67; 95% CI: 2.44–18.21) concentrations had higher risk for preeclampsia.

Conclusion: NGAL and PCT may be potential biomarkers for preeclampsia. Their levels increase significantly in preeclampsia and they are related to the severity of the disease. These results are in agreement with the generalized endothelial damage and persistant inflammatory status in preeclampsia. NGAL may also be an indicator for adverse neonatal outcomes with decreased placental hypoperfusion.  相似文献   
3.
4.
5.
6.
The relationship between erectile dysfunction (ED) and chronic renal failure (CRF) has been reported in several studies. This study aimed to investigate whether the chronic use of sildenafil could enhance the erectile capacity in CRF-induced rats. In addition, we assessed the effect of that treatment on certain molecules, which have been suggested to play crucial roles in erectile physiology and CRF-related ED as well. Three groups of animals were utilized: (1) age-matched control rats, (2) CRF-induced rats, (3) CRF-induced rats treated with chronic administration of sildenafil (5 mg kg−1 p.o. for 6 weeks [treatment started after 6 weeks of CRF induction]). At 3 months, all animals underwent cavernosal nerve stimulation (CNS) to assess erectile function. Penile tissue advanced glycation end products (AGE''s)/5-hydroxymethyl-2-furaldehyde, malondialdehyde (MDA), cGMP (ELISA), inducible nitric oxide synthase (iNOS) and neuronal NOS (nNOS) (Western blot) analyses were performed in all rat groups. CRF-induced rats had a significant decrease in erectile function when compared to control rats (P < 0.05). The increase in both intracavernosal pressure (ICP) and area under the curve of CRF-induced rats treated with sildenafil (Group 3) was greater than CRF-induced rats (Group 2). Additionally, sildenafil treatment decreased AGE, MDA and iNOS levels, while it preserved nNOS and cGMP contents in CRF-induced penile tissue. Decreased AGE, MDA, iNOS and increased nNOS, cGMP levels at the sildenafil-treated group increased both ICP and Total ICP to CNS, which led to improve erectile function in CRF-induced rats. The results of the present study revealed the therapeutic effect of chronic sildenafil administration on erectile function in CRF-induced rats.  相似文献   
7.

Background

Little is known about regulatory CD4 T cells (Tregs) in the context of HIV vaccines. Tregs can be differentiated into resting (FoxP3+CD45RA+ – rTregs), activated (FoxP3HighCD45RA? – aTregs) and memory (FoxP3LowCD45RA? – mTregs). Tregs, as CD4 T cells, are also frequent targets for HIV infection. We studied how the abundance and phenotypes of Tregs in terms of activation status and expression of HIV-1 binding molecules would have changed during vaccination in healthy volunteers participating in a phase IIa HIV vaccine clinical trial. Subjects were primed three times with HIVIS-DNA and boosted twice with MVA-CMDR-HIV alone (n?=?12) or MVA-CMDR combined with protein CN54rgp140 (n?=?13). The proportions of β7 integrin in all CD4 T cells and in the Tregs subset decreased moderately after the final vaccination (p?=?0.001 and p?=?0.033, respectively) and the rTregs proportion within the total Tregs were also decreased after the final vaccination (p?=?0.038). All these proportions returned to normal values within the three months after the final vaccination. The magnitude of HIV-Envelope-specific IFNγ?+?T cells after vaccination (r?=?0.66; p?=?0.021) correlated directly with the proportion of Tregs, and correlated inversely correlated with ratios of Th17/Tregs (r?=??0.75; p?=?0.0057) and Th17/mTregs (r?=??0.78; p?=?0.0065). Higher titers of IgG gp140 antibodies were observed in subjects with higher mTregs proportions (r?=?0.52; p?=?0.022). Interestingly, pre-vaccination levels of mTregs correlated with vaccine-induced Env-binding antibodies (r?=?0.57; p?=?0.01) and presence of neutralizing antibodies (r?=?0.61; p?=?0.01), while the pre-vaccination Th17/mTregs ratio correlated inversely with the magnitude of cellular IFN-γ ELISpot responses (r?=??0.9; p?=?0.002). Taken together, these results suggest that pre- and post-vaccination Tregs, their activation status, the Th17/Tregs ratio and other host factors affecting Treg abundance, have an impact on the magnitude of HIV vaccine-induced immune responses. Moreover, the DNA-HIVIS/MVA-HIV regimen, alone or in combination with CN54rgp140 induced moderate and temporary alterations of the Tregs activation status. We also show a decrease in expression of the HIV-1 ligand β7 integrin on Tregs and all CD4 T cells.  相似文献   
8.
9.
Hereditary hemochromatosis (HH) is a frequent genetic disease of older subjects of northern European descent. It is characterized by increased iron absorption and severe iron overloading in parenchymal organs. A similar disturbance of iron metabolism occurs in specific animal species in captivity. To address the key features leading to high absorption and thus to iron overload in these animals, we have studied the two iron transport proteins DMT1 and Ireg1 in the best-known susceptible species, the mynah bird. Here, we show that these birds have a high expression of DMT1 in the duodenum and also a strikingly high expression of Ireg1 along the whole small intestine. We believe that the iron accumulation in susceptible species only occurs in captivity because of a genotypic adaptation to their natural environment, where contrary to captivity, dietary iron is hardly available. The Caucasian population carrying mutations leading to iron overload today may have also benefited from the genetic advantage of up-regulating iron transport millennia ago, when dietary iron was scarce.  相似文献   
10.
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