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   5767篇
  免费   535篇
  国内免费   116篇
耳鼻咽喉   44篇
儿科学   151篇
妇产科学   250篇
基础医学   719篇
口腔科学   76篇
临床医学   599篇
内科学   1138篇
皮肤病学   107篇
神经病学   441篇
特种医学   400篇
外科学   763篇
综合类   179篇
预防医学   331篇
眼科学   103篇
药学   426篇
中国医学   26篇
肿瘤学   665篇
  2023年   32篇
  2022年   55篇
  2021年   129篇
  2020年   99篇
  2019年   180篇
  2018年   181篇
  2017年   123篇
  2016年   144篇
  2015年   187篇
  2014年   224篇
  2013年   330篇
  2012年   377篇
  2011年   383篇
  2010年   275篇
  2009年   219篇
  2008年   302篇
  2007年   307篇
  2006年   279篇
  2005年   284篇
  2004年   259篇
  2003年   219篇
  2002年   212篇
  2001年   182篇
  2000年   152篇
  1999年   155篇
  1998年   79篇
  1997年   77篇
  1996年   64篇
  1995年   49篇
  1994年   34篇
  1993年   46篇
  1992年   88篇
  1991年   81篇
  1990年   59篇
  1989年   63篇
  1988年   59篇
  1987年   58篇
  1986年   47篇
  1985年   61篇
  1984年   44篇
  1983年   27篇
  1982年   26篇
  1981年   19篇
  1980年   14篇
  1979年   12篇
  1978年   20篇
  1977年   14篇
  1975年   15篇
  1974年   11篇
  1969年   9篇
排序方式: 共有6418条查询结果,搜索用时 15 毫秒
981.
982.

Objectives  

1) to correlate thigh muscle volume measured by magnetic resonance image (MRI) with anthropometric measurements and physical function in elderly subjects; 2) to predict MRI-measured thigh muscle volume using anthropometric measurements and physical functional status in elderly subjects.  相似文献   
983.
984.
985.

Background and aims

Heparin-binding EGF-like growth factor (HB-EGF) is a representative EGF family member that interacts with EGFR under diverse stress environment. Previously, we reported that the HB-EGF-targeting using antisense oligonucleotide (ASO) effectively suppressed an aortic aneurysm in the vessel wall and circulatory lipid levels. In this study, we further examined the effects of the HB-EGF ASO administration on the development of hyperlipidemia-associated atherosclerosis using an atherogenic mouse model.

Methods and results

The male and female LDLR deficient mice under Western diet containing 21% fat and 0.2% cholesterol content were cotreated with control and HB-EGF ASOs for 12 weeks. We observed that the HB-EGF ASO administration effectively downregulated circulatory VLDL- and LDL-associated lipid levels in circulation; concordantly, the HB-EGF targeting effectively suppressed the development of atherosclerosis in the aorta. An EGFR blocker BIBX1382 administration suppressed the hepatic TG secretion rate, suggesting a positive role of the HB-EGF signaling for the hepatic VLDL production. We newly observed that there was a significant improvement of the insulin sensitivity by the HB-EGF ASO administration in a mouse model under the Western diet as demonstrated by the improvement of the glucose and insulin tolerances.

Conclusion

The HB-EGF ASO administration effectively downregulated circulatory lipid levels by suppressing hepatic VLDL production rate, which leads to effective protection against atherosclerosis in the vascular wall.  相似文献   
986.
987.

Objective

To compare perioperative and long-term outcomes in patients undergoing hemiarch and aggressive arch replacement for acute type A aortic dissection (ATAAD).

Methods

From 1996 to 2017, we compared outcomes of hemiarch (n = 322) versus aggressive arch replacements (zones 2 and 3 arch replacement with implantation of 2-4 arch branches, n = 150) in ATAAD. Indications for aggressive arch were arch aneurysm >4 cm or intimal tear in the aortic arch that was not resectable by hemiarch replacement, or dissection of arch branches with malperfusion.

Results

Patients in the aggressive arch group were significantly younger (mean age: 57 vs 61 years old) and had significantly longer hypothermic circulatory arrest, cardiopulmonary bypass, and aortic crossclamp times. There were no significant differences in perioperative outcomes between hemiarch and aggressive arch groups, including 30-day mortality (5.3% vs 7.3%, P = .38) and postoperative stroke rate (7% vs 7%, P = .96). Over 15 years, Kaplan–Meier survival was similar between hemiarch and aggressive arch groups (log-rank P = .55, 10-year survival 70% vs 72%). Given death as a competing factor, incidence rates of reoperation over 15 years (2.1% vs 2.0% per year, P = 1) and 10-year cumulative incidence of reoperation (14% vs 12%, P = .89) for arch and distal aorta pathology were similar between the 2 groups.

Conclusions

Both hemiarch and aggressive arch replacement are appropriate approaches for select patients with ATAAD. Aggressive arch replacement should be considered for an arch aneurysm >4 cm or an intimal tear at the arch unable to be resected by hemiarch replacement, or dissection of the arch branches with malperfusion.  相似文献   
988.
989.
990.

Objectives

Among symptomatic dancers, sonographic abnormalities are common. Whether asymptomatic dancers have any abnormalities remains unknown. Some dancers became cyanosis over distal feet after ballet training. The hemodynamic changes at the feet in ballet are not clearly understood.

Design

Cross-sectional study.

Methods

In 25 dancers and 14 non-dancers, B-mode ultrasonography was used to measure cross-sectional areas (CSA) of tendons of deep posterior compartment muscles. Doppler ultrasonography was used to measure peak velocity (Vpeak) of posterior tibial artery in three ankle postures: the neutral position, passively and forced actively plantar flexion (en pointe). The big toe oxygen saturation was recorded in neutral position and during 1-min en pointe. Single-leg standing heel rise test was performed to represent the muscle function.

Results

The CSA of FHL was larger in dancers (0.26 cm2 [0.20, 0.30] vs 0.21 cm2 [0.17, 0.24], p < 0.01), while other tendons were not different (all p > 0.05). Higher Vpeak was recorded in passively plantar flexion than in neutral position (p < 0.01, in both groups). The blood flow was undetectable during en pointe, more frequently in dancers (54.9% vs 14.3%, p < 0.01). Oxygen saturation decreased during en pointe more prominently in dancers (85% [80, 90] vs 94% [84, 97], p < 0.01). There was no significant difference in muscle function.

Conclusions

US showed the FHL tendon thickening and en pointe-related vascular compromise in pre-professional dancers, even when they are asymptomatic.  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