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   123946篇
  免费   10819篇
  国内免费   8077篇
耳鼻咽喉   1034篇
儿科学   1551篇
妇产科学   2320篇
基础医学   14742篇
口腔科学   2062篇
临床医学   16076篇
内科学   19829篇
皮肤病学   1448篇
神经病学   6804篇
特种医学   4299篇
外国民族医学   70篇
外科学   12874篇
综合类   18901篇
现状与发展   24篇
一般理论   5篇
预防医学   7527篇
眼科学   3625篇
药学   12662篇
  114篇
中国医学   6077篇
肿瘤学   10798篇
  2024年   227篇
  2023年   1624篇
  2022年   2689篇
  2021年   5848篇
  2020年   4211篇
  2019年   4080篇
  2018年   4138篇
  2017年   3711篇
  2016年   3471篇
  2015年   5221篇
  2014年   6551篇
  2013年   6112篇
  2012年   8922篇
  2011年   9775篇
  2010年   5952篇
  2009年   4741篇
  2008年   6510篇
  2007年   6508篇
  2006年   6541篇
  2005年   6492篇
  2004年   4460篇
  2003年   4213篇
  2002年   3562篇
  2001年   3222篇
  2000年   3315篇
  1999年   3441篇
  1998年   2234篇
  1997年   2162篇
  1996年   1566篇
  1995年   1459篇
  1994年   1269篇
  1993年   820篇
  1992年   1228篇
  1991年   1077篇
  1990年   932篇
  1989年   824篇
  1988年   712篇
  1987年   652篇
  1986年   503篇
  1985年   463篇
  1984年   249篇
  1983年   178篇
  1982年   118篇
  1981年   116篇
  1980年   76篇
  1979年   120篇
  1978年   59篇
  1976年   52篇
  1975年   55篇
  1974年   65篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.

Background

Rosacea is a chronic inflammatory skin condition whose etiology has been linked to mast cells and the antimicrobial peptide cathelicidin LL-37. Individuals with refractory disease have demonstrated clinical benefit with periodic injections of onabotulinum toxin, but the mechanism of action is unknown.

Objectives

To investigate the molecular mechanism by which botulinum toxin improves rosacea lesions.

Methods

Primary human and murine mast cells were pretreated with onabotulinum toxin A or B or control. Mast cell degranulation was evaluated by β-hexosaminidase activity. Expression of botulinum toxin receptor Sv2 was measured by qPCR. The presence of SNAP-25 and VAMP2 was established by immunofluorescence. In vivo rosacea model was established by intradermally injecting LL-37 with or without onabotulinum toxin A pretreatment. Mast cell degranulation was assessed in vivo by histologic counts. Rosacea biomarkers were analyzed by qPCR of mouse skin sections.

Results

Onabotulinum toxin A and B inhibited compound 48/80-induced degranulation of both human and murine mast cells. Expression of Sv2 was established in mouse mast cells. Onabotulinum toxin A and B increased cleaved SNAP-25 and decreased VAMP2 staining in mast cells respectively. In mice, injection of onabotulinum toxin A significantly reduced LL-37-induced skin erythema, mast cell degranulation, and mRNA expression of rosacea biomarkers.

Conclusions

These findings suggest that onabotulinum toxin reduces rosacea-associated skin inflammation by directly inhibiting mast cell degranulation. Periodic applications of onabotulinum toxin may be an effective therapy for refractory rosacea and deserves further study.  相似文献   
62.
63.
64.
综述近年中医药治疗慢性前列腺炎的临床研究,认为本病病因病机之核心在于脾肾亏虚为本,湿热、痰浊、瘀毒为标,病久则伤及脾肾,由实转虚。中医内治法主要以辨证论治、辨病论治或单方验方为主,外治法以中药洗浴、中药灌肠、肛门给药、针灸为主。中医药治疗本病优势明显。应继续完善对中医药作用机制的认识,制订统一的辨证论治及疗效评价标准,针对效果显著的名方开展研究。  相似文献   
65.
G protein-coupled estrogen receptor-1 (GPER), a member of the G protein-coupled receptor (GPCR) superfamily, mediates estrogen-induced proliferation of normal and malignant breast epithelial cells. However, its role in breast cancer stem cells (BCSCs) remains unclear. Here we showed greater expression of GPER in BCSCs than non-BCSCs of three patient-derived xenografts of ER/PR+ breast cancers. GPER silencing reduced stemness features of BCSCs as reflected by reduced mammosphere forming capacity in vitro, and tumor growth in vivo with decreased BCSC populations. Comparative phosphoproteomics revealed greater GPER-mediated PKA/BAD signaling in BCSCs. Activation of GPER by its ligands, including tamoxifen (TMX), induced phosphorylation of PKA and BAD-Ser118 to sustain BCSC characteristics. Transfection with a dominant-negative mutant BAD (Ser118Ala) led to reduced cell survival. Taken together, GPER and its downstream signaling play a key role in maintaining the stemness of BCSCs, suggesting that GPER is a potential therapeutic target for eradicating BCSCs.  相似文献   
66.
67.
Two new bisamides, aglaiamides A (1) and B (2), along with three known ones (35), were isolated from the leaves of Aglaia perviridis. Their structures were established on the basis of detailed spectroscopic analyses.  相似文献   
68.
69.
BackgroundOur study aims to investigate changes in cell-free DNA (cfDNA) concentration and integrity in primary hepatocellular carcinoma (PHC) patients before and after transcatheter arterial chemoembolization (TACE) treatment and their influence on the evaluation of prognosis of the disease.MethodsA total of 84 PHC patients admitted to the Affiliated Hospital of Nanjing University of Chinese Medicine from December 2016 to December 2017 were included as the study group, while 55 healthy people served as the control group. Plasma cfDNA concentration and integrity were determined using qRT-PCR. The correlation between cfDNA concentration/integrity and clinical characteristics of PHC patients were analyzed. A ROC curve was used to investigate the sensitivity and specificity of cfDNA as detection indices. Univariate and multivariate analyses were used to analyze factors affecting recurrence in PHC patients and compare recurrence-free survival (RFS) of PHC patients with high cfDNA expression and low cfDNA expression.ResultsPlasma cfDNA concentration and integrity were significantly higher in PHC patients before TACE treatment than in healthy people and significantly lower after treatment than before (P<0.05). The cfDNA concentration was significantly correlated with tumor size, lymph node metastasis, TNM stage, and BCLC stage, while cfDNA integrity was significantly correlated with tumor size, TNM stage, and BCLC stage (P<0.05). ROC results showed that the area under the curve (AUC) value of cfDNA concentration was the largest, with an optimal cut-off of 10.51 ng/mL. Multivariate regression analysis for COX showed that the TNM stage, cfDNA concentration, and AFP were independent risk factors that affected PHC patients’ survival.ConclusionsPlasma cfDNA concentration in PHC patients is more sensitive and specific than any other tumor marker. It is an independent risk factor for PHC patients treated with TACE. Therefore, it is hypothesized cfDNA is a potential biomarker for prognostic evaluation of PHC patients treated with TACE.  相似文献   
70.
Capillary malformation–arteriovenous malformation syndrome (CM‐AVM) is an autosomal dominant disorder caused by RASA1 mutations. The prevalence and phenotypic spectrum are unknown. Evaluation of patients with multiple CMs is challenging because associated AVMs can be life threatening. The objective of this study was to describe the clinical characteristics of children presenting with features of CM‐AVM to an academic pediatric dermatology practice. After institutional review board approval was received, a retrospective chart review was performed of patients presenting between 2009 and 2012 with features of CM‐AVM. We report nine cases. Presenting symptoms ranged from extensive vascular stains and cardiac failure to CMs noted incidentally during routine skin examination. All demonstrated multiple CMs, two had Parkes Weber syndrome, and two had multiple infantile hemangiomas. Seven patients had family histories of multiple CMs; three had family histories of large, atypical CMs. Six had personal or family histories of AVMs. Genetic evaluation was recommended for all and was pursued by six families; four RASA1 mutations were identified, including one de novo. Consultations with neurology, cardiology, and orthopedics were recommended. Most patients (89%) have not required treatment to date. CM‐AVM is an underrecognized condition with a wide clinical spectrum that often presents in childhood. Further evaluation may be indicated in patients with multiple CMs. This study is limited by its small and retrospective nature.  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