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   1431篇
  免费   208篇
  国内免费   86篇
耳鼻咽喉   26篇
儿科学   10篇
妇产科学   39篇
基础医学   144篇
口腔科学   20篇
临床医学   136篇
内科学   207篇
皮肤病学   34篇
神经病学   51篇
特种医学   49篇
外科学   164篇
综合类   130篇
预防医学   53篇
眼科学   17篇
药学   165篇
中国医学   14篇
肿瘤学   466篇
  2024年   6篇
  2023年   130篇
  2022年   165篇
  2021年   133篇
  2020年   189篇
  2019年   80篇
  2018年   93篇
  2017年   69篇
  2016年   80篇
  2015年   87篇
  2014年   127篇
  2013年   67篇
  2012年   60篇
  2011年   41篇
  2010年   64篇
  2009年   61篇
  2008年   28篇
  2007年   70篇
  2006年   26篇
  2005年   10篇
  2004年   23篇
  2003年   13篇
  2002年   9篇
  2001年   9篇
  2000年   16篇
  1999年   9篇
  1998年   9篇
  1997年   3篇
  1996年   6篇
  1995年   9篇
  1994年   6篇
  1993年   7篇
  1992年   6篇
  1991年   1篇
  1990年   4篇
  1989年   3篇
  1988年   3篇
  1985年   2篇
  1984年   1篇
排序方式: 共有1725条查询结果,搜索用时 390 毫秒
991.
Human P-glycoprotein (P-gp), encoded by MDR1 (ABCB1), is an efflux transporter with a wide specificity for substrates/drugs, including HIV protease inhibitors which are commonly used in HIV/AIDS treatment. Three single nucleotide polymorphisms (SNPs) in MDR1 have been shown to affect P-gp expression and function, and may affect HIV/AIDS treatment outcome: 1236C>T [G412G, exon-12], 2677G>T/A [A893S/T, exon-21] and 3435C>T [I1145I, exon-26]. In the present study, our aims were (i) to compare the 3-SNP MDR1 haplotype structure and genetic diversity between North American HIV-positive and HIV-negative individuals belonging to four major ethnic groups and (ii) to determine whether the haplotype structure and genetic diversity observed in these ethnically admixed populations differ from that in ethnically non-admixed populations. For these aims, we analyzed a cohort of 447 HIV/AIDS patients (White [n = 193], Black [n = 235], Hispanic [n = 17], and Asian [n = 2]). Results obtained for these patients were compared with the results for (i) HIV-negative individuals (n = 356) and (ii) various HapMap and Environmental Genome Project populations. We observed that the genetic characteristics of MDR1 were largely consistent between HIV-positive and HIV-negative populations, but there were striking interethnic differences in the genetic characteristics of MDR1 in both populations. Although it appeared that the genetic characteristics of MDR1 were largely consistent between ethnically admixed and non-admixed populations, genetic characterization of the admixed populations remains to be done. Thus, our results provide useful comparative insights about the genetic characteristics of MDR1 that could be extrapolated across population groups worldwide. For a meaningful interpretation of these results regarding HIV/AIDS treatment outcome, MDR1 haplotype/diplotype structure data, genetic characterization of population admixture, and polymorphisms in other relevant drug transporter and/or metabolizing enzyme genes should be considered in future clinical studies.  相似文献   
992.
993.
Von Willebrand factor (vWf) is an adhesive glycoprotein known to play an important role in hemostasis and in tissue injury. Because the latter process resembles hepatic fibrogenesis, we studied the tissue distribution of vWf in diseased livers. In normal rat liver vWf was strongly expressed in the vascular endothelium and as small spots or fiber-like structures in the hepatic parenchyma. During acute liver injury, pronounced staining was observed within the area of necrosis. In fibrotic livers vWf deposits were distributed predominantly at the scar-parenchyma interface but also within the septum and in sinusoidal lining cells. Testing different liver cell populations in vitro demonstrated that vWf gene expression was limited to endothelial cells (ECs) and, therefore, the latter cell population might represent the vWf-positive cells detected in vivo. The distribution of vWf within fibrotic septa suggests that vWf becomes a component of the extracellular matrix (ECM) in fibrotic livers.  相似文献   
994.
目的 观察白细胞介素6抗体(IL-6)/蛋白酪氨酸激酶2抗体(JAK2)/信号传导和转录激活因子3抗体(STAT3)对口腔鳞状细胞癌(简称口腔鳞癌)细胞生物学行为的影响.方法 对口腔鳞癌细胞系进行慢病毒转染敲低IL-6基因,设立两组对照,一组为未干预组,另一组为空白载体组.通过CCK8实验和克隆形成实验检测IL-6对口...  相似文献   
995.
996.
The identification of tumor-associated antigens, which are specifically expressed in cancer tissues, is very important for immunotherapy of lung cancer. We have combined the in silico screening and experimental verifying to identify genes that are differently expressed in cancers compared with their corresponding normal tissues. Using these methods, we have identified that GABRA3 gene was overexpressed in lung cancer and rarely expressed in other cancers. Furthermore, GABRA3 protein expression was significantly higher in the lower grade of lung cancer. It may compose functional GABA-gated channel with other subunits. This study demonstrated GABRA3 could be a potential biomarker for diagnosis of lung cancer, and GABAA receptors may play an important role in cancer differentiation.  相似文献   
997.
Obesity is a modern day epidemic. The incidence appears to be rapidly increasing in both developed and developing countries and has become much more obvious in the last decade. It is regarded as one of the major risk factors in pregnant women and has particularly gained recognition in obstetric practice due to its potentially adverse effects on pregnancy and the fetus.There is evidence to show that obesity in pregnancy contributes to increased morbidity and mortality in both mother and baby. It is associated with adverse outcomes such as preeclampsia, gestational diabetes, thromboembolism, fetal abnormalities and large for gestational infants. According to the Confidential Enquiries into Maternal Deaths in the United Kingdom, 35% of the women who died had a BMI of 30 or more. All these issues highlight the immense importance in treating women with obesity in maternity practice accordingly.  相似文献   
998.
Prophylactic vaccination against HPV 16 and 18 has the potential for effective prevention of high-grade precancer (cervical intraepithelial neoplasia [CIN)] 2/3) and ICC caused by these viruses (globally 50 and 70%, respectively) when employed in women prior to starting sexual activity. To provide data for decisions on HPV vaccination in China, we determined HPV type-distribution in ICC and CIN 2/3 from women of different regions within China. A multicenter study was conducted by randomized sampling of paraffin blocks of 664 ICC (630 squamous cell carcinoma [SCC]; 34 adenocarcinoma [ADC]), 569 CIN 2/3 cases from seven regions of China. Histological diagnosis was confirmed in 1,233 cases by consensus review. HPV DNA was detected using the SPF10 LiPA25 version 1 assay. HPV prevalence was 97.6% in SCC, 85.3% in adenocarcinoma, and 98.9% in CIN 2/3. HPV 16 (76.7%) and HPV 18 (7.8%) were the most common, together accounting for 84.5% of SCC, followed by HPV 31 (3.2%), HPV 52 (2.2%), and HPV 58 (2.2%). HPV positivity in SCC did not differ notably by region. However, SCC cases from women ≤34 years had higher HPV 16 positivity than women over 50 years, among whom HPV 52, 58, and 39 were more common. HPV 16 and 18 were under-represented, whereas HPV 31, 52, and 58 were over-represented in CIN2/3 compared to SCC. The potential impact of vaccines against oncogenic HPV types 16 and 18 is estimated to be high (84.5%) against total SCC. These data are critical for China’s future evaluation of the cost-effectiveness of current cervical cancer vaccines and of HPV-based screening guidelines.  相似文献   
999.
DIARY OF EVENTS     
《The Foot》2000,10(3):174
  相似文献   
1000.
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