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   26876篇
  免费   1251篇
  国内免费   196篇
耳鼻咽喉   255篇
儿科学   423篇
妇产科学   299篇
基础医学   3450篇
口腔科学   629篇
临床医学   1836篇
内科学   7178篇
皮肤病学   388篇
神经病学   2089篇
特种医学   1048篇
外科学   4615篇
综合类   112篇
一般理论   2篇
预防医学   675篇
眼科学   446篇
药学   1907篇
中国医学   96篇
肿瘤学   2875篇
  2023年   152篇
  2022年   254篇
  2021年   528篇
  2020年   276篇
  2019年   379篇
  2018年   460篇
  2017年   368篇
  2016年   467篇
  2015年   518篇
  2014年   689篇
  2013年   847篇
  2012年   1366篇
  2011年   1478篇
  2010年   810篇
  2009年   684篇
  2008年   1240篇
  2007年   1362篇
  2006年   1316篇
  2005年   1451篇
  2004年   1354篇
  2003年   1268篇
  2002年   1271篇
  2001年   788篇
  2000年   805篇
  1999年   764篇
  1998年   383篇
  1997年   291篇
  1996年   309篇
  1995年   234篇
  1994年   230篇
  1993年   194篇
  1992年   552篇
  1991年   554篇
  1990年   509篇
  1989年   491篇
  1988年   388篇
  1987年   346篇
  1986年   373篇
  1985年   340篇
  1984年   240篇
  1983年   203篇
  1982年   103篇
  1980年   105篇
  1979年   182篇
  1978年   123篇
  1977年   113篇
  1974年   100篇
  1972年   106篇
  1969年   98篇
  1968年   102篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

Background

Photosensitizers used for photodynamic therapy (PDT) to treat dermatologic disease are metabolized into mainly protoporphyrin IX (PpIX), which has five absorption wavelength peaks: 410?nm, 510?nm, 545?nm, 580?nm, and 630?nm. Although only red light around 635?nm and blue light around 400?nm are used as light sources for PDT, the efficiency of PDT might be improved by using multiple wavelengths, including those that correspond to the other absorption peaks of PpIX. Furthermore, because the target disease often occurs on the face, a flexible-type light-source unit that can be fitted to the lesion without unnecessarily exposing the mucous membranes, e.g., the eyes, nostrils, and mouth, is preferred.

Objective

We investigated the efficacy of a flexible light-emitting diode (LED) unit that emits multiple wavelengths to improve PDT effects.

Methods

HaCaT cells were incubated with 5-ALA and subsequently irradiated with either a single wavelength or sequentially with two wavelengths. Cell viability and reactive oxygen species were analyzed. Nude mice were implanted with COLO679 cells by subcutaneous injection into the flank. 5-ALA was subcutaneously injected into the tumor. The tumor was irradiated with 50?J/cm2 (day 0) and assessed daily until day 21.

Results

The synergistic PDT effects of dual-wavelength irradiation and reactive oxygen species production were highest with the 405-nm and 505-nm wavelength combination. This dual wavelength combination was also the most effective in vivo.

Conclusion

We could therefore conclude that dual-wavelength PDT is an efficient strategy for improving the therapeutic effects of PDT. Using a flexible LED unit is expected to achieve more uniform irradiation of uneven areas.  相似文献   
2.
3.
4.
5.
6.
7.

Background

There were few studies assessed the postoperative sarcopenia in patients with cancers. The objective of present study was to assess whether postoperative development of sarcopenia could predict a poor prognosis in patients with adenocarcinoma of esophagogastric junction, (AEG) and upper gastric cancer (UGC).

Methods

Patients with AEG and UGC who were judged as non-sarcopenic before surgery were reassessed the presence of postoperative development of sarcopenia 6 months after surgery. Patients were divided into the development group or non-development group, and clinicopathological factors and prognosis between these two groups were analyzed.

Results

The 5-year overall survival rates were significantly poorer in the development group than non-development group (68.0% vs. 92.6%, P?=?0.0118). Multivariate analyses showed that postoperative development of sarcopenia was an independent prognostic factor for poor overall survival (P?=?0.0237).

Conclusions

Postoperative development of sarcopenia was associated with a poor prognosis in patients with AEG and UGC.  相似文献   
8.
<正>Stroke is a leading cause of mortality and severe neurological disability worldwide; however, curative therapeutic options are limited. Although recanalization therapy using endovascular thrombectomy has demonstrated great benefits in the functional outcome of patients with acute ischemic stroke, the rate of excellent clinical outcomes remains limited. Therefore, the current recanalization  相似文献   
9.
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