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   4385篇
  免费   254篇
  国内免费   17篇
耳鼻咽喉   40篇
儿科学   126篇
妇产科学   51篇
基础医学   475篇
口腔科学   165篇
临床医学   423篇
内科学   1050篇
皮肤病学   49篇
神经病学   473篇
特种医学   313篇
外科学   634篇
综合类   39篇
一般理论   1篇
预防医学   302篇
眼科学   70篇
药学   219篇
中国医学   10篇
肿瘤学   216篇
  2024年   8篇
  2023年   38篇
  2022年   69篇
  2021年   131篇
  2020年   81篇
  2019年   110篇
  2018年   129篇
  2017年   80篇
  2016年   128篇
  2015年   102篇
  2014年   179篇
  2013年   176篇
  2012年   293篇
  2011年   301篇
  2010年   189篇
  2009年   200篇
  2008年   236篇
  2007年   233篇
  2006年   223篇
  2005年   224篇
  2004年   170篇
  2003年   163篇
  2002年   153篇
  2001年   77篇
  2000年   46篇
  1999年   51篇
  1998年   69篇
  1997年   78篇
  1996年   86篇
  1995年   57篇
  1994年   51篇
  1993年   55篇
  1992年   27篇
  1991年   21篇
  1990年   29篇
  1989年   44篇
  1988年   41篇
  1987年   38篇
  1986年   48篇
  1985年   26篇
  1984年   24篇
  1983年   18篇
  1982年   30篇
  1981年   16篇
  1980年   13篇
  1978年   15篇
  1977年   17篇
  1976年   19篇
  1975年   16篇
  1969年   6篇
排序方式: 共有4656条查询结果,搜索用时 15 毫秒
71.
Frontotemporal lobar degeneration with motor neuron disease (FTLD-MND) is characterized by neuronal cytoplasmic inclusions containing TDP-43. Apolipoprotein E4 (apoE4), derived from the apoE ?4 allele, enhances brain atrophy in FTLD through unknown mechanisms. Here, we studied two siblings with C9ORF72-linked familial FTLD-MND, an apoE ?4 homozygote and an apoE ?3 homozygote. The apoE ?4 homozygote had more cognitive-behavioral symptoms, fronto-insulo-temporal atrophy, and apoE fragments and aggregates in the anterior cingulate cortex. ApoE formed complexes with TDP-43 that were more abundant in the apoE ?4 homozygote. Although differences seen in a sibling pair could arise due to chance, these findings raise the possibility that apoE4 exacerbates brain pathology in FTLD through formation of neurotoxic apoE fragments and interactions with TDP-43.  相似文献   
72.
73.
74.
75.

Key points

  • Intrauterine growth restriction (IUGR) is associated with short‐ and long‐term detrimental cardiometabolic effects.
  • Mice and rats are commonly used to assess IUGR, but differences in placental and fetal developmental physiology relative to those in humans highlight the need for alternative small animal IUGR models.
  • We developed a guinea pig IUGR model by gradual occlusion of uterine arteries by ameroid constrictor implantation. In this model, reduced uterine blood flow was associated with IUGR, allowing in vivo assessment of fetal growth trajectory and umbilico‐placental vascular function in conscious animals.
  • The intervention induces placental vascular dysfunction and remodelling, as well as altered fetal abdominal growth resulting in an asymmetric IUGR and preserved brain growth.

Abstract

Intra‐uterine growth restriction (IUGR) is associated with short and long‐term metabolic and cardiovascular alterations. Mice and rats have been extensively used to study the effects of IUGR, but there are notable differences in fetal and placental physiology relative to those of humans that argue for alternative animal models. This study proposes that gradual occlusion of uterine arteries from mid‐gestation in pregnant guinea pigs produces a novel model to better assess human IUGR. Fetal biometry and in vivo placental vascular function were followed by sonography and Doppler of control pregnant guinea pigs and sows submitted to surgical placement of ameroid constrictors in both uterine arteries (IUGR) at mid‐gestation (35 days). The ameroid constrictors induced a reduction in the fetal abdominal circumference growth rate (0.205 cm day−1) compared to control (0.241 cm day−1, P < 0.001) without affecting biparietal diameter growth. Umbilical artery pulsatility and resistance indexes at 10 and 20 days after surgery were significantly higher in IUGR animals than controls (P < 0.01). These effects were associated with a decrease in the relative luminal area of placental chorionic arteries (21.3 ± 2.2% vs. 33.2 ± 2.7%, P < 0.01) in IUGR sows at near term. Uterine artery intervention reduced fetal (∼30%), placental (∼20%) and liver (∼50%) weights (P < 0.05), with an increased brain to liver ratio (P < 0.001) relative to the control group. These data demonstrate that the ameroid constrictor implantations in uterine arteries in pregnant guinea pigs lead to placental vascular dysfunction and altered fetal growth that induces asymmetric IUGR.  相似文献   
76.
77.

Background

Facio-Scapulo-Humeral Muscular Dystrophy (FSHD) is an autosomal dominant inherited disorder characterized by a variable and asymmetric involvement of facial, trunk, upper and lower extremity muscles. Although respiratory weakness is a relatively unknown feature of FSHD, it is not rare. Telemedicine has been used in a variety of health care fields, but only recently, with the advent of sophisticated technology, its interest among health professionals became evident, even in such diseases.

Objective

To demonstrate the telemedicine efficacy in FSHD.

Methods

Four siblings affected by a severe form of FSHD, living in a rural area far away from the referral center for neuromuscular diseases, who used a wheelchair, suffered from chronic respiratory failure and were provided with long-term non-invasive mechanical ventilation, received a 6-month period of telemedicine support. This consisted of video conferencing (respiratory physiotherapy, psychological support, neurological and pneumological assessment, nurse-coach supervision) and telemonitoring of cardiorespiratory variables (oxygen saturation, blood pressure, and heart rate).

Results

We performed 540 video conference sessions per patient, including three daily contacts with short monitoring oximetry measurements, blood pressure, and heart-rate measurements, psychological support, neurological and pneumological assessment, nurse-coach supervision.

Conclusions

Our findings indicate that our telemedicine system was user-friendly, efficient for the home treatment of FSHD, and allowed reducing hospital admissions.  相似文献   
78.
79.
80.
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