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   967篇
  免费   70篇
  国内免费   139篇
耳鼻咽喉   12篇
儿科学   6篇
妇产科学   10篇
基础医学   149篇
口腔科学   52篇
临床医学   168篇
内科学   226篇
皮肤病学   23篇
神经病学   51篇
特种医学   66篇
外科学   80篇
综合类   23篇
预防医学   23篇
眼科学   7篇
药学   157篇
  1篇
中国医学   8篇
肿瘤学   114篇
  2024年   3篇
  2023年   11篇
  2022年   19篇
  2021年   42篇
  2020年   26篇
  2019年   23篇
  2018年   23篇
  2017年   21篇
  2016年   30篇
  2015年   57篇
  2014年   72篇
  2013年   68篇
  2012年   98篇
  2011年   83篇
  2010年   37篇
  2009年   31篇
  2008年   35篇
  2007年   128篇
  2006年   39篇
  2005年   37篇
  2004年   29篇
  2003年   32篇
  2002年   13篇
  2001年   30篇
  2000年   17篇
  1999年   11篇
  1998年   13篇
  1997年   24篇
  1996年   21篇
  1995年   4篇
  1994年   14篇
  1993年   16篇
  1992年   8篇
  1991年   19篇
  1990年   7篇
  1989年   12篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1977年   4篇
  1975年   1篇
  1974年   1篇
排序方式: 共有1176条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
Gestational diabetes mellitus (GDM) is a strong predictor of postpartum prediabetes and transition to overt type 2 diabetes (T2DM). Although many reports indicate that low magnesium is correlated with deteriorated glucose tolerance, the association between postpartum serum magnesium level and the risk for T2DM in women with a history of GDM has not been evaluated. We analyzed postpartum serum magnesium levels and development of prediabetes and T2DM in women with prior GDM according to American Diabetes Association (ADA) criteria using the Korean National Diabetes Program (KNDP) GDM cohort. During a mean follow-up of 15.6±2.0 months after screening, 116 women were divided into three groups according to glucose tolerance status. Ultimately, eight patients (6.9%) were diagnosed with T2DM, 59 patients (50.9%) with prediabetes, and 49 patients (42.2%) with normal glucose tolerance (NGT) after follow-up. The T2DM group had the lowest serum magnesium level (0.65 [0.63-0.68] mM/L) in the postpartum period, but there was no significant difference between the prediabetes group (0.70 [0.65-0.70] mM/L) and the NGT group (0.70 [0.65-0.70] mM/L) (P=0.073) Multiple logistic regression analysis showed that postpartum HOMA-IR was a significant predictor of both prediabetes and T2DM. Moreover, we found that postpartum serum magnesium level was also a possible predictor for T2DM development. Serum magnesium level in the postpartum period may be a possible predictor for T2DM development in women with a history of GDM.  相似文献   
15.
An effective method is described for producing poly(3,4‐ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) arched microwires, which are used as transducers in chemiresistive gas sensors. Three‐dimensional arched wires with diameters of 0.8, 1.2, 2.5, and 10 μm are individually fabricated by using a simple, inexpensive fountain‐pen lithography technique. The wires show superior stretchable behavior under omnidirectional strain of ca. 120%. A gas sensor assembled with the PEDOT:PSS arched wires exhibits linear responses to the concentrations of different vapor gases, such as ethanol, acetone, and methanol, at room temperature. The signal‐to‐noise ratio in the sensing response, which influences the detection limit, is enhanced by increasing the number of wires with a larger surface‐to‐volume ratio in parallel to increasing the signal level and diminishing the baseline noise in the wire transducers.

  相似文献   

16.
Coronary artery fistula is rare anomalies. Most adult patients are usually asymptomatic. A fistula is incidentally identified in the adult using echocardiography. Coronary angiography is considered the standard tool to confirm a coronary artery fistula. However, multidetector computed tomography (MDCT) angiography is considered a good alternative to coronary angiography.  相似文献   
17.
18.
There is a need to develop mechanically active culture systems to better understand the role of mechanical stresses in intervertebral disc (IVD) degeneration. Motion segment cultures that preserve the native IVD structure and adjacent vertebral bodies are preferred as model systems, but rapid ex vivo tissue degeneration limits their usefulness. The stability of rat and rabbit IVDs is of particular interest, as their small size makes them otherwise suitable for motion segment culture. The goal of this study was to determine if there are substantial differences in the susceptibility of rat and rabbit IVDs to culture‐induced degeneration. Lumbar IVD motion segments were harvested from young adult male Sprague–Dawley rats and New Zealand White rabbits and cultured under standard conditions for 14 days. Biochemical assays and safranin‐O histology showed that while glycosaminoglycan (GAG) loss was minimal in rabbit IVDs, it was progressive and severe in rat IVDs. In the rat IVD, GAG loss was concomitant with the loss of notochordal cells and the migration of endplate (EP) cells into the nucleus pulposus (NP). None of these changes were evident in the rabbit IVDs. Compared to rabbit IVDs, rat IVDs also showed increased matrix metalloproteinase‐3 (MMP‐3) and sharply decreased collagen type I and II collagen expression. Together these data indicated that the rabbit IVD was dramatically more stable than the rat IVD, which showed culture‐related degenerative changes. Based on these findings we conclude that the rabbit motion segments are a superior model for mechanobiologic studies. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 838–846, 2013  相似文献   
19.
Yoo  Seol Bong  Kim  Yu Jung  Kim  Hyojin  Jin  Yan  Sun  Ping-Li  Jheon  Sanghoon  Lee  Jong Seok  Chung  Jin-Haeng 《Annals of surgical oncology》2013,20(3):545-552
Background

Epidermal growth factor receptor (EGFR) mutation alone may be insufficient to predict clinical outcomes in the response to EGFR-tyrosine kinase inhibitor (TKI) therapy. The secondary mutation T790 M and MET amplification are mechanisms of acquired resistance to EGFR-TKI in approximately 50 % of patients, but the remaining mechanisms are unknown.

Methods

Eight metastatic lesions and specimens from 41 non-small cell lung carcinoma (NSCLC) patients harbouring activating EGFR mutations who underwent surgical resection and EGFR-TKI therapy were available. Immunohistochemistry was used to evaluate E-cadherin, β-catenin, and PTEN. Chromogenic in situ hybridisation and silver-enhanced in situ hybridisation were used to evaluate EGFR and MET amplification.

Results

Patients with E-cadherin/β-catenin alteration showed a poor objective response rate (ORR) (p = 0.005) and shorter overall survival (p = 0.059). Additionally, β-catenin alteration was associated with a poor ORR (p = 0.012). Of the metastatic tumours, three cases (37.5 %) showed the acquisition of altered E-cadherin/β-catenin and PTEN loss and two cases (25 %) demonstrated MET/EGFR amplification.

Conclusions

Altered E-cadherin/β-catenin expression in NSCLC harbouring EGFR mutations was associated with a poor response to EGFR-TKI. During metastatic progression, changes in E-cadherin/β-catenin were found. These results may suggest that E-cadherin/β-catenin alteration is related to poor TKI response and resistance.

  相似文献   
20.
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