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   147篇
  免费   4篇
  国内免费   1篇
妇产科学   6篇
基础医学   33篇
口腔科学   7篇
临床医学   12篇
内科学   29篇
神经病学   7篇
特种医学   1篇
外科学   10篇
综合类   3篇
预防医学   24篇
药学   12篇
中国医学   3篇
肿瘤学   5篇
  2023年   1篇
  2022年   7篇
  2021年   6篇
  2020年   3篇
  2019年   11篇
  2018年   7篇
  2017年   5篇
  2016年   2篇
  2015年   3篇
  2014年   5篇
  2013年   8篇
  2012年   8篇
  2011年   7篇
  2010年   9篇
  2009年   7篇
  2008年   8篇
  2007年   10篇
  2006年   9篇
  2005年   7篇
  2004年   7篇
  2003年   5篇
  2002年   7篇
  2001年   2篇
  1999年   3篇
  1998年   1篇
  1997年   2篇
  1995年   1篇
  1980年   1篇
排序方式: 共有152条查询结果,搜索用时 0 毫秒
31.
Objective: Fetal fatty acid (FA) delivery is ultimately controlled by placental transport. Focus has been the maternal-placental interface, but regulation at the feto-placental interface is unknown.

Methods: Placental macrovascular endothelial cells (EC) (n?=?4/group) and trophoblasts (TB) (n?=?5/group) were isolated from lean (pregravid BMI <25?kg/m2) and obese (body mass index (BMI)?>?30) women. Fatty acid transporters FAT/CD36, FABPpm, FATP4, FABP 3, 4 and 5, PLIN2 and PPARα, δ, γ expression, was measured in EC and TB. Transporter response to 24?h palmitate (PA) was assessed.

Results: mRNA expression of FABP3, 4, 5 and PPARγ was 2- to 3-fold reduced in EC of obese versus lean women (p?p?p?p?p?Conclusions: In obese women, FA transporter expression is lower in placental EC, but not TB, and less sensitive to saturated FA, compared to lean women. FA transport may be regulated at the feto-placental interface.  相似文献   
32.
33.
Adenine dinucleotides are a group of extracellular modulators involved in maintaining blood vessel tone. We have demonstrated previously that Ap2A and Ap4A induce the synthesis of both nitric oxide (NO) and prostacyclin (PGI2) in bovine aortic endothelial cells (BAEC), whereas Ap3A, Ap5A, and Ap6A do not. In this paper, we report that Ap2A and Ap4A are partial agonists for ATP in terms of Ca2+ mobilization and PGI2 synthesis. The Ap(4)A EC50 values for Ca2+ mobilization and PGI2 synthesis were significantly higher than the corresponding values for ATP, while the Ap4A B(max) values for Ca2+ mobilization and PGI2 synthesis were significantly lower than those for ATP. Ap2A and Ap4A concentration-effect curves for Ca2+ mobilization and PGI2 synthesis demonstrated that Ap2A and Ap4A have antagonistic effects at ATP concentrations that induce responses above the maximal amount of Ca2+ mobilized or PGI2 synthesized by these two dinucleotides. On the other hand, Ap2A and Ap4A have agonistic effects at ATP concentrations that induce PGI2 synthesis below the maximal amount of PGI2 synthesized by these two dinucleotides. We also present evidence that suggests Ap3A, Ap5A, and Ap6A are antagonists for ATP in terms of PGI2 synthesis. All these data are consistent with the adenine dinucleotides being negative modulators for ATP-induced PGI2 synthesis.  相似文献   
34.
35.
Pleomorphic adenoma (PA) is the most common salivary gland tumor and its microscopic features and histogenesis are a matter of debate. Human milk fat globule protein membrane (HMFG) monoclonal antibodies (MoAbs) comprise a set of antibodies against the mucin 1 (MUC-1) protein detected in several salivary gland tumors.

Objective

The aim of this study was to assess the immunoexpression of the PA neoplastic cells to MUC-1 protein using HMFG-1 and HMFG-2 MoAbs, contrasting these results with those from normal salivary gland tissue.

Material and Methods

Immunohistochemical detection of MUC-1 protein using HMFG-1 and HMFG-2 MoAbs was made in 5 mm thick, paraffin embedded slides, and the avidin-biotin method was used.

Results

Positivity to HMFG-1 and HMFG-2 MoAbs was found in ductal, squamous metaplastic and neoplastic myoepithelial cells, keratin pearls and intraductal mucous material. Two kinds of myoepithelial cells were identified: classic myoepithelial cells around ducts were negative to both MoAbs, and modified myoepithelial cells were positive to both MoAbs. This last cellular group of the analyzed tumors showed similar MUC-1 immunoexpression to ductal epithelial cells using both HMFG antibodies. Intraductal mucous secretion was also HMFG-1 and HMFG-2 positive.

Conclusions

Our results showed there are two kinds of myoepithelial cells in PA. The first cellular group is represented by the different kinds of neoplastic myoepithelial cells and is HMFG-positive. The second one is HMFG-negative and represented by the neoplastic myoepithelial cells located around the ducts.  相似文献   
36.
Leishmaniasis is a zoonotic disease caused by predominantly vectorborne Leishmania spp. In the United States, canine visceral leishmaniasis is common among hounds, and L. infantum vertical transmission among hounds has been confirmed. We found that L. infantum from hounds remains infective in sandflies, underscoring the risk for human exposure by vectorborne transmission.  相似文献   
37.
OBJECTIVE: Several genome-wide screens have been performed in autism spectrum disorders resulting in the identification of numerous putative susceptibility loci. Analyses of pooled primary data should result in an increased sample size and the different study samples have a potential to strengthen the evidence for some earlier identified loci, reveal novel loci, and even to provide information of the general significance of the locus. The objective of this study was to search for potential susceptibility loci for autism, which are supported by two independent samples. METHODS: We performed a combined analysis of the primary genome scan data of the Autism Genetic Resource Exchange (AGRE) and Finnish autism samples to reveal susceptibility loci potentially shared by these study samples. RESULTS: In the initial combined data analysis, the best loci (p < 0.05) were observed at 1p12-q25, 3p24-26, 4q21-31, 5p15-q12, 6q14-21, 7q33-36, 8q22-24, 17p12-q21, and 19p13-q13. The combined analysis of Finnish and AGRE families showed the most promising shared locus on 3p24-26 with nonparametric logarithm of odds (NPL) score of 2.20 (p = 0.011). The combined data analysis did not provide increased linkage evidence for the earlier identified loci on 3q25-27 or 17p12-q21. However, the 17p12-q21 locus remained promising also in the combined sample (NPL(all) =2.38, p = 0.0076). INTERPRETATION: Our study of 314 autism families highlights the importance of further analyses on 3p24-26 locus involving comprehensive molecular genetic analyses of oxytocin receptor gene (OXTR), a positional and functional candidate gene for autism.  相似文献   
38.
Sex steroid hormones have been shown to regulate somatostatin (SRIF) gene expression in goldfish brain, which in turn influences the regulation of GH secretion. In this study, the influences of sex steroids on pituitary responsiveness to SRIF-14 and the pituitary expression of a type two SRIF receptor (sst(2)) were examined. Results from in vitro perifusion of pituitary fragments show that pituitaries from estradiol-primed sexually regressed female fish have significantly lower GH release responsiveness to pulse exposure to SRIF-14 than pituitaries from control or testosterone-treated sexually regressed females. Results from in vitro static culture show that pituitaries from sexually mature female fish have lower GH release responsiveness to SRIF-14 than those from sexually regressed females. In addition, the sst(2) receptor mRNA levels in pituitaries from mature and recrudescent female fish are significantly lower than in sexually regressed female fish. Our results indicate that estradiol acts at the level of the pituitary to regulate GH secretion by influencing the responsiveness to SRIF-14. The underlying mechanism includes, in part, reduction of the expression of sst(2) receptors, presumably leading to the lower number of the receptors available for SRIF binding.  相似文献   
39.
40.
To investigate the origin of the beta(A) and beta(S) genes in a Mexican population with African roots and a high frequency of hemoglobin S, we analyzed 467 individuals (288 unrelated) from different towns in the states of Guerrero and Oaxaca in the Costa Chica region. The frequency of the sickle-cell trait was 12.8%, which may represent a public health problem. The frequencies of the beta-haplotypes were determined from 350 nonrelated chromosomes (313 beta(A) and 37 beta(S)). We observed 15 different beta(A) haplotypes, the most common of which were haplotypes 1 (48.9%), 2 (13.4%), and 3 (13.4%). The calculation of pairwise distributions and Nei's genetic distance analysis using 32 worldwide populations showed that the beta(A) genes are more closely related to those of Mexican Mestizos and North Africans. Bantu and Benin haplotypes and haplotype 9 were related to the beta(S) genes, with frequencies of 78.8, 18.2, and 3.0%, respectively. Comparison of these haplotypes with 17 other populations revealed a high similitude with the population of the Central African Republic. These data suggest distinct origins for the beta(A) and beta(S) genes in Mexican individuals from the Costa Chica region.  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