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   921篇
  免费   203篇
  国内免费   2篇
耳鼻咽喉   10篇
儿科学   37篇
妇产科学   67篇
基础医学   81篇
口腔科学   8篇
临床医学   294篇
内科学   196篇
皮肤病学   14篇
神经病学   40篇
特种医学   45篇
外科学   94篇
综合类   5篇
预防医学   109篇
眼科学   5篇
药学   39篇
中国医学   1篇
肿瘤学   81篇
  2024年   4篇
  2023年   29篇
  2022年   33篇
  2021年   53篇
  2020年   41篇
  2019年   25篇
  2018年   55篇
  2017年   54篇
  2016年   55篇
  2015年   55篇
  2014年   64篇
  2013年   63篇
  2012年   65篇
  2011年   61篇
  2010年   42篇
  2009年   68篇
  2008年   42篇
  2007年   37篇
  2006年   42篇
  2005年   15篇
  2004年   29篇
  2003年   19篇
  2002年   14篇
  2001年   10篇
  2000年   7篇
  1999年   11篇
  1998年   20篇
  1997年   20篇
  1996年   16篇
  1995年   6篇
  1994年   6篇
  1993年   7篇
  1992年   6篇
  1991年   4篇
  1990年   3篇
  1989年   6篇
  1988年   3篇
  1986年   2篇
  1985年   3篇
  1984年   2篇
  1981年   2篇
  1980年   3篇
  1978年   2篇
  1977年   4篇
  1976年   4篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1971年   2篇
  1967年   1篇
排序方式: 共有1126条查询结果,搜索用时 15 毫秒
1.
2.
3.
IL-8 mRNA in human gingival epithelial cells (HGECs) is up-regulated by Fusobacterium nucleatum, and up-/down-regulated by Porphyromonas gingivalis in a complex interaction in the early stages (< or = 4 h) after infection. The mechanisms involved in this regulation in response to F. nucleatum and/or P. gingivalis infection, and identification of co-regulated cytokine genes, are the focus of this investigation. Heat, formalin or protease treatment of F. nucleatum cells attenuated the IL-8 mRNA up-regulation. NF-kappaB, mitogen-activated protein kinase (MAPK) p38 and MAPK kinase/extracellular signal-regulated kinase (MEK/ERK) pathways were involved in IL-8 mRNA induction by F. nucleatum. Pretreatment of P. gingivalis with heat, formalin or protease enhanced IL-8 mRNA induction. NF-kappaB, MARK p38, and MEK/ERK pathways were also involved in this induction. In contrast, down-regulation of IL-8 mRNA by P. gingivalis involved MEK/ERK, but not NF-kappaB or MAPK p38 pathways. cDNA arrays analysis revealed that mRNA down-regulation by P. gingivalis is a specific reaction that only a number of genes, e.g. IL-1beta, IL-8, macrophage inflammatory protein-2alpha, and migration inhibitory factor-related protein-14, are affected based on examination of 278 cytokine/receptor genes. These data indicate that F. nucleatum and P. gingivalis trigger specific and differential gene regulation pathways in HGECs.  相似文献   
4.
5.
6.
A bleached sulfate integrated pulp and paper mill producing printing and writing paper from mixed tropical hardwood and bamboo was studied. The mill uses a “conventional bleaching sequence,” C-E-H1-H2, with an average molecular chlorine consumption of 50 kg per ton of air-dried pulp (ADP). The content of polychlorinated dibenzofurans (PCDFs) and dibenzo-p-dioxins (PCDDs) in the bleaching filtrate in terms of the nordic toxicity equivalent (N-TEQ) was 33.5, 1.15, 0.56, and 0.014 pg/L for the E, C, H1, and H2 bleaching stages, respectively. The corresponding PCDFs and PCDDs loads in ng/t ADP were in the same ranking, i.e., 670, 69, 11.2, and 0.28, respectively. The congener and isomeric pattern of PCDFs and PCDDs of the bleaching filtrate and the bleached pulp was found to be typical for the chlorine bleaching plant effluent. The obtained dioxin load formed in the mill is in agreement with Western studies for the given multiple chlorine of 0.21–0.23. The load is, however, lower than reported discharges from Scandinavian mills using 1980s bleaching technologies, but substantially higher than the discharges from mills with modern bleaching technologies. Modifications in the bleaching plant to reduce molecular chlorine use are necessary to reduce dioxin formation. Received: 15 July 1998/Accepted: 17 March 1999  相似文献   
7.
The purpose of the present work is to "quantify" bone scanning, in order to calculate indices of localized uptake that will make it possible to differentiate between normal and pathological uptake, and approach an etiologicial diagnosis. The authors use an Elscint dual head whole body scanner and an offline video display calculator. The patient is given 8 mc technetium 99m pyrophosphate 4 hours prior to scanning. The whole body count is expressed in thousands of counts multipled by two so that the knee to whole body ratio is close to one, to facilitate comparison of the indices. Results show that the presence of metastases is demonstrated more clearly by using a ratio bone segment to whole body. Quantitative scanning with 99mTc-pyrophosphate makes it possible to: 1) detect bone metastases easily, 2) follow the metastases during treatment, 3) avoid the gross errors that can be made in nomquantitative scanning.  相似文献   
8.
Concise methods for the synthesis of 4‐hydroxy‐3‐[2H3]‐methoxyphenylalanine (3‐O‐[2H3]‐methydopa) and 3‐hydroxy‐4‐[2H3]‐methoxyphenylalanine (4‐O‐[2H3]‐methydopa) are described. The 3‐O‐[2H3]‐methydopa is a valuable internal standard for the tandem MS quantification of 3‐O‐methyldopa, a metabolite of value in the diagnosis of aromatic l‐amino acid decarboxylase (AADC) deficiency. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
9.

Background

In April 2007, the National Quality Forum (NQF) endorsed the first nationally recognized hospital-based performance measures for stage I, II, and III breast cancer. The purpose of this study was to document compliance with the 3 NQF breast quality indicators during 2 time intervals in a metropolitan public hospital.

Materials and Methods

Tumor registry and medical records were used to identify patient demographics and treatments before (2005–2006) and after (2008) implementations in 2007 as a result of the NQF audit. Program changes included: hiring a dedicated medical oncology nurse practitioner, requiring the radiation oncology case manager to attend weekly multidisciplinary conferences, educating Patient Navigators of the importance of multimodal care, and providing support groups for patients addressing importance of completion of all treatment options.

Results

A total of 213 female patients were diagnosed with and treated for stage I, II, or III breast cancer in 2005–2006 and 2008. Of these, 189 (89%) were African American (AA) women. Also, 70 patients of 86 (81.3%) received radiation therapy, 60 of 77 (77.9%) received or were considered for adjuvant chemotherapy, and 124 of 144 (86.1%) for hormonal therapy according to NQF indicators. After 2007, patients receiving radiation therapy increased from 75.8 to 95.8%. Patients receiving or considered for adjuvant chemotherapy or hormonal therapy increased from 73.7 to 93.7% and from 84.1 to 90.0%, respectively.

Conclusions

NQF breast cancer indicators provided a mechanism to improve compliance of multimodal treatment in our center. Raising awareness of these indicators in the multidisciplinary conference, hiring dedicated personnel, and educating patients has led to major improvements in breast cancer care.  相似文献   
10.
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