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   2367篇
  免费   93篇
  国内免费   44篇
耳鼻咽喉   15篇
儿科学   26篇
妇产科学   33篇
基础医学   262篇
口腔科学   61篇
临床医学   155篇
内科学   642篇
皮肤病学   24篇
神经病学   185篇
特种医学   129篇
外科学   401篇
综合类   5篇
预防医学   48篇
眼科学   22篇
药学   149篇
中国医学   3篇
肿瘤学   344篇
  2023年   26篇
  2022年   61篇
  2021年   50篇
  2020年   38篇
  2019年   48篇
  2018年   46篇
  2017年   40篇
  2016年   66篇
  2015年   65篇
  2014年   71篇
  2013年   98篇
  2012年   130篇
  2011年   154篇
  2010年   82篇
  2009年   60篇
  2008年   117篇
  2007年   121篇
  2006年   146篇
  2005年   143篇
  2004年   142篇
  2003年   144篇
  2002年   145篇
  2001年   39篇
  2000年   40篇
  1999年   43篇
  1998年   39篇
  1997年   26篇
  1996年   38篇
  1995年   23篇
  1994年   23篇
  1993年   11篇
  1992年   14篇
  1991年   19篇
  1990年   23篇
  1989年   19篇
  1988年   17篇
  1987年   8篇
  1986年   6篇
  1985年   11篇
  1984年   9篇
  1983年   8篇
  1982年   6篇
  1981年   5篇
  1977年   4篇
  1976年   5篇
  1975年   8篇
  1974年   11篇
  1973年   7篇
  1972年   12篇
  1971年   6篇
排序方式: 共有2504条查询结果,搜索用时 15 毫秒
991.
992.
993.
Aflibercept plus 5‐fluorouracil/levofolinate/irinotecan (FOLFIRI) is a second‐line treatment for metastatic colorectal cancer. This ancillary exploratory analysis of data in Japanese people was aimed at exploring the relationship between a set of potential prognostic biomarkers and efficacy endpoints following aflibercept plus FOLFIRI therapy. Sixty‐two patients with metastatic colorectal cancer received aflibercept (4 mg/kg) plus FOLFIRI every 2 weeks. Seventy‐eight potential protein biomarkers were chosen for analysis based on their roles in angiogenesis, tumor progression, and tumor‐stroma interaction. Plasma levels of biomarkers at baseline and at pre‐dose 3 (day 1 of treatment cycle 3) were measured in all patients by ELISA. Relationships between these levels and efficacy endpoints were assessed. Ten potential biomarkers had a ±30% change from baseline to pre‐dose 3 (adjusted < .001), with the greatest changes occurring in placental growth factor (median: +4716%) and vascular endothelial growth factor receptor 1 (+2171%). Baseline levels of eight potential biomarkers correlated with overall survival in a univariate Cox regression analysis: extracellular newly identified receptor for advanced glycation end‐products binding protein, insulin‐like growth factor‐binding protein 1, interleukin‐8, kallikrein 5, pulmonary surfactant‐associated protein D, tissue inhibitor of metalloproteinases 1, tenascin‐C, and tumor necrosis factor receptor 2. None correlated with progression‐free survival or maximum tumor shrinkage. Pre‐dose 3 levels did not correlate with any efficacy endpoints. Preliminary data show that these eight biomarkers could be associated with overall survival. ClinicalTrials.gov identifier: NCT01882868.  相似文献   
994.
995.
Purpose To investigate global protein expression profiles in the retinas of normal and glucocorticoid-induced ocular hypertensive rats by proteomic analysis. Methods Ocular hypertension was induced by topical application of dexamethasone (DEX) for 4 weeks. Age-matched untreated rats served as controls. Intraocular pressure (IOP) was monitored by an electronic tonometer. Retinal protein expression profiling was carried out by two-dimensional fluorescence difference gel electrophoresis (2-D DIGE). Proteins were identified by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. Results In DEX-treated rats, average IOP was elevated significantly compared with controls. With DEX treatment, levels of four proteins were altered, as revealed by 2-D DIGE and MALDI-TOF mass spectrometry: apolipoprotein A1 (apoA1), a lipid-binding protein, upregulated 1.9-fold, P < 0.05; alpha A crystallin (CRYAA), a molecular chaperone, downregulated 2.7-fold, P < 0.01; superoxide dismutase 1 (SOD1), an antioxidant enzyme, downregulated 2.3-fold, P < 0.05; and triosephosphate isomerase 1 (TPI1), a glycolytic enzyme, downregulated 2.3-fold, P < 0.01. Conclusions Downregulation of CRYAA, SOD1, and TPI1, observed here after a short period of DEX-induced ocular hypertension, may be involved in the onset of neural damage in steroid-induced glaucoma.  相似文献   
996.
997.
Institutional review board approval and informed patient consent were obtained. The purpose of the study was to prospectively evaluate the use of radiosensitive indicators to estimate patient entrance skin dose (ESD). Forty-six patients wore a jacket with 48 or 52 indicators adhered to the back during percutaneous coronary interventions; they had eight additional indicators on their upper arms. The patients' ESDs were calculated according to the change in color of the indicators. There were good correlations between the ESDs estimated by using color measurements performed with an optical instrument and those estimated at visual observation (P < .001) and between the ESDs estimated by using a thermoluminescent dosimeter and those estimated by using color measurements (P < .001). The radiosensitive indicator method seems to be useful for estimating ESDs and their distribution during percutaneous coronary intervention; however, visual observation is reliable for estimating doses of up to 5 Gy only. (c) RSNA, 2006.  相似文献   
998.
Leptin is a hormone which is predominantly secreted by adipose tissue. Recent studies have shown that leptin increases arterial blood pressure. Although data from available animal studies clearly indicate an association between leptin and hypertension, results of human studies have been less definitive. We conducted a case-control study to examine the association between serum leptin levels and hypertension in 111 hypertensive subjects and 222 male controls, using conditional logistic regression analyses. Mean serum leptin levels were found to be marginally higher in the case subjects than in the control subjects (3.3 ng/ml versus 3.0 ng/ml), however, conditional logistic regression analysis revealed that subjects in the highest quartile had a significantly increased risk of hypertension compared with those in the lowest quartile, even after adjusting for drinking status and diabetes mellitus (adjusted OR, 2.11;95% CI, 1.01-4.39). Our findings suggest that leptin plays an important role in the development of hypertension.  相似文献   
999.
Three rotavirus variants with a rearranged RNA segment derived from the NSP3 gene were isolated in three independent experiments of coinfection and multiple passages of simian rotavirus strain SA11 and single-VP7-gene- or NSP1-gene-substitution reassortants having genetic background of SA11. Sequence analysis indicated that the three rearranged NSP3 genes had almost identical sequences and genomic structures organized by partial duplication of the open reading frame in a head-to-tail orientation following the termination codon. The junction site of the original NSP3 gene (first copy) and the duplicated portion (second copy) was identical among the three rearranged genes, while a direct repeat, i.e., a homologous sequence between the first copy and second template for duplication, typically located at the junction site, was not detected. However, short similar sequences were present at the end of the first copy and beginning of the second copy. These findings suggest that rearrangement of the NSP3 gene may occur at a certain preferential site which is related to sequence similarity between 3′-untranslated region and a region near the 5′-end of ORF.  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