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   31756篇
  免费   2958篇
  国内免费   2372篇
耳鼻咽喉   234篇
儿科学   259篇
妇产科学   331篇
基础医学   3742篇
口腔科学   490篇
临床医学   4684篇
内科学   4642篇
皮肤病学   249篇
神经病学   1710篇
特种医学   1060篇
外国民族医学   21篇
外科学   2904篇
综合类   5399篇
现状与发展   5篇
一般理论   2篇
预防医学   1820篇
眼科学   1192篇
药学   3559篇
  26篇
中国医学   1886篇
肿瘤学   2871篇
  2024年   113篇
  2023年   564篇
  2022年   1472篇
  2021年   1755篇
  2020年   1354篇
  2019年   1210篇
  2018年   1115篇
  2017年   1155篇
  2016年   996篇
  2015年   1584篇
  2014年   1848篇
  2013年   1521篇
  2012年   2316篇
  2011年   2534篇
  2010年   1510篇
  2009年   1178篇
  2008年   1575篇
  2007年   1552篇
  2006年   1608篇
  2005年   1815篇
  2004年   993篇
  2003年   854篇
  2002年   779篇
  2001年   674篇
  2000年   651篇
  1999年   760篇
  1998年   536篇
  1997年   499篇
  1996年   391篇
  1995年   365篇
  1994年   301篇
  1993年   212篇
  1992年   231篇
  1991年   212篇
  1990年   191篇
  1989年   143篇
  1988年   146篇
  1987年   106篇
  1986年   101篇
  1985年   66篇
  1984年   29篇
  1983年   24篇
  1982年   11篇
  1981年   19篇
  1980年   9篇
  1979年   8篇
排序方式: 共有10000条查询结果,搜索用时 23 毫秒
991.
992.
Xie LX  Chen YS  Liu SY 《Chest》2012,141(1):241-244
Cardiac lipomas are rare, mostly asymptomatic, and usually found incidentally during noncardiac examinations; however, they also can be symptomatic, depending on their size and location. Here, we report a case of surgically proved pericardial lipoma that was big and for which cardiac structures were substantially altered. The combination of CT imaging and ultrasonography enabled a precise diagnosis in terms of localization, tissue characterization, and complications of the tumor. The origin of the tumor, however, remains undetermined despite a series of postoperative CT scan and ultrasound examinations.  相似文献   
993.
J Jiang  P Chen  J Chen  X Yu  D Xie  C Mei  F Xiong  W Shi  W Zhou  X Liu  S Sun  P Zhang  X Yang  Y Zhang  Y Zhang  X Liang  Z Zhang  Q Lin  Y Yu  T Miyata  J Tian  M Liang  W Luo  X Xu  F Hou 《Atherosclerosis》2012,224(1):187-194
ObjectivesAccumulation of tissue advanced glycation end products (AGEs) is a marker of cumulative glycemic and/or oxidative stress. Cutaneous AGEs levels measured by skin autofluorescence correlate well with cardiovascular outcomes in diabetes and hemodialysis (HD) patients. The present study aimed to compare tissue AGEs levels with peritoneal dialysis (PD) and HD patients and to evaluate the relationship between skin autofluorescence and cardiovascular morbidity in patients on PD.MethodsA total of 2388 maintenance dialysis patients (613 PD and 1775 HD) were enrolled in this cross-sectional study. Skin autofluorescence was measured non-invasively with an autofluorescence reader. Cardiovascular morbidity was defined as clinically diagnosed ischemic heart disease, heart failure, stroke or peripheral vascular disease from initiation of dialysis.ResultsMore than 90% of patients on both PD and HD had met current dialysis adequacy targets. Compared to HD group, PD patients receiving conventional glucose-containing dialyzate had significantly higher skin autofluorescence values in each category of age and dialysis duration, irrespective of the presence or absence of diabetes. In PD patients, skin autofluorescence values were strongly correlated with the duration of PD and glucose exposure dose and independently associated with cardiovascular morbidity. Multivariate analysis revealed that glucose exposure dose and skin autofluorescence were the strongest risk factors for cardiovascular morbidity in PD patients after adjustment by age, gender, and other classic- or uremic-related risk factors.ConclusionsAccumulation of tissue AGEs provides a potential link between PD exposure of metabolic stress and progression of cardiovascular disease in patients on PD.  相似文献   
994.
995.
Protein-trafficking pathways are targeted here in human melanoma cells using methods independent of oncogene mutational status, and the ability to up-regulate and down-regulate tumor treatment sensitivity is demonstrated. Sensitivity of melanoma cells to cis-diaminedichloroplatinum II (cDDP, cis-platin), carboplatin, dacarbazine, or temozolomide together with velaparib, an inhibitor of poly (ADP ribose) polymerase 1, is increased by up to 10-fold by targeting genes that regulate both protein trafficking and the formation of melanosomes, intracellular organelles unique to melanocytes and melanoma cells. Melanoma cells depleted of either of the protein-trafficking regulators vacuolar protein sorting 33A protein (VPS33A) or cappuccino protein (CNO) have increased nuclear localization of cDDP, increased nuclear DNA damage by platination, and increased apoptosis, resulting in increased treatment sensitivity. Depleted cells also exhibit a decreased proportion of intracellular, mature melanosomes compared with undepleted cells. Modulation of protein trafficking via cell-surface signaling by binding the melanocortin 1 receptor with the antagonist agouti-signaling protein decreased the proportion of mature melanosomes formed and increased cDDP sensitivity, whereas receptor binding with the agonist melanocyte-stimulating hormone resulted in an increased proportion of mature melanosomes formed and in decreased sensitivity (i.e., increased resistance) to cDDP. Mutation of the protein-trafficking gene Hps6, known to impair the formation of mature melanosomes, also increased cDDP sensitivity. Together, these results indicate that targeting protein-trafficking molecules markedly increases melanoma treatment sensitivity and influences the degree of melanosomes available for sequestration of therapeutic agents.  相似文献   
996.
997.
998.
999.
1000.
Huang B  Cheng Y  Xie Q  Lin G  Wu Y  Feng Y  Gao J  Xu D 《Clinical cardiology》2012,35(2):125-130

Background:

There are few recent data to delineate the beyond lipids‐decreased effect of statins and the effect of different doses of statins on endothelial‐derived microparticles (EMPs) and circulating endothelial progenitor cells (EPCs) in patients with ischemic cardiomyopathy (ICM).

Hypothesis:

Statins might have the beyond lipids‐decreased effect and there were different effects between different doses of statins on EMPs and circulating EPCs in patients with ICM.

Methods:

One hundred patients with ICM and 100 healthy examined people, who served as the normal control group, were recruited to this study. Patients were randomly divided into 2 groups: 10‐mg atorvastatin group (n = 50) and 40‐mg atorvastatin group (n = 50). All subjects were followed for 1 year. The levels of serum lipids, oxidized low‐density lipoprotein (oxLDL), high‐sensitivity C‐reactive protein (hsCRP), circulating EPCs, and EMPs were examined in all subjects. The incidences of adverse reactions in the 2 study groups were determined.

Results:

At the beginning of this study, there were no significant differences in baseline characteristics between the 2 study groups. At the end of this study, the levels of total cholesterol, low‐density lipoprotein, serum hsCRP, oxLDL, and circulating EMPs were significantly decreased; circulating EPCs were significantly increased in the 40‐mg atorvastatin group compared to the 10‐mg atorvastatin group, P < 0.05. The multivariate linear regression analysis indicated that receiving only 40 mg of atorvastatin had a significant effect on the levels of circulating EPCs (β = 0.252,P = 0.014). There were no significant differences in the adverse reactions between the 2 groups.

Conclusions:

Use of 40 mg of atorvastatin might decrease the levels of circulating EMPs and increase the number of circulating EPCs in patients with ICM in comparison with 10 mg of atorvastatin, and the effect might be independent of the decrease of lipids, oxLDL, and hsCRP. © 2012 Wiley Periodicals, Inc. This study was supported by the Bureau of Health of Guangzhou city (2009‐YB‐186). The authors have no other funding, financial relationships, or conflicts of interest to disclose.  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