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   53132篇
  免费   3594篇
  国内免费   181篇
耳鼻咽喉   602篇
儿科学   1070篇
妇产科学   798篇
基础医学   6814篇
口腔科学   693篇
临床医学   4909篇
内科学   12849篇
皮肤病学   533篇
神经病学   5191篇
特种医学   2101篇
外科学   8478篇
综合类   587篇
一般理论   65篇
预防医学   3663篇
眼科学   926篇
药学   3186篇
中国医学   49篇
肿瘤学   4393篇
  2024年   42篇
  2023年   286篇
  2022年   601篇
  2021年   1435篇
  2020年   901篇
  2019年   1294篇
  2018年   1641篇
  2017年   1118篇
  2016年   1205篇
  2015年   1440篇
  2014年   2162篇
  2013年   2511篇
  2012年   4326篇
  2011年   4293篇
  2010年   2402篇
  2009年   2151篇
  2008年   3757篇
  2007年   3867篇
  2006年   3740篇
  2005年   3684篇
  2004年   3289篇
  2003年   3029篇
  2002年   2738篇
  2001年   320篇
  2000年   224篇
  1999年   331篇
  1998年   487篇
  1997年   439篇
  1996年   356篇
  1995年   326篇
  1994年   252篇
  1993年   237篇
  1992年   146篇
  1991年   132篇
  1990年   117篇
  1989年   98篇
  1988年   91篇
  1987年   70篇
  1986年   75篇
  1985年   102篇
  1984年   122篇
  1983年   107篇
  1982年   136篇
  1981年   109篇
  1980年   96篇
  1979年   42篇
  1978年   60篇
  1977年   58篇
  1976年   49篇
  1975年   40篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Objective: To determine whether packed red blood cell (PRBC) transfusion affects post-prandial superior mesenteric artery blood flow velocities (SMA BFVs) in very-low birth weight (VLBW) neonates and if so, at what time point after transfusion restoration of previous SMA BFV patterns occurs.

Design/Methods: VLBW pre-term neonates, older than 14 days and tolerating bolus enteral feedings administered every 3?h were enrolled in this prospective observational study. Pulsed Doppler ultrasound was used to measure pre- and post-prandial (at 45?min) time-averaged mean, peak and end diastolic velocities (TAMV, PSV, EDV) immediately before and after 15?ml/kg of PRBC transfusion was given over 3?h; patent ductus arteriosus (PDA) status was also evaluated. Subsequent pre- and post-prandial SMA BFVs were recorded 24 and 48?h after the transfusion.

Results: Pre- and post-prandial measurements were obtained for 21 out of 25 enrolled infants. Post-prandial SMA BFVs were attenuated during the feedings immediately after transfusion; at 24 and 48?h after transfusion, changes in post-prandial SMA BFVs were similar to those measured prior to transfusion; the presence of the PDA did not affect results.

Conclusions: PRBC transfusion blunted SMA BFV responses to feedings immediately after the transfusion with normalization observed 24?h post-transfusion.  相似文献   
2.
3.
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.  相似文献   
4.
5.
There is a large and growing population of long-term cancer survivors. Primary care physicians (PCPs) are playing an increasingly greater role in the care of these patients across the continuum of cancer survivorship. In this role, PCPs are faced with the responsibility of managing a range of medical and psychosocial late effects of cancer treatment. In particular, the sexual side effects of treatment which are common and have significant impact on quality of life for the cancer survivor, often go unaddressed. This is an area of clinical care and research that has received increasing attention, highlighted by the presentation of this special issue on Cancer and Sexual Health. The aims of this review are 3-fold. First, we seek to overview common presentations of sexual dysfunction related to major cancer diagnoses in order to give the PCP a sense of the medical issues that the survivor may present with. Barriers to communication about sexual health issues between patient/PCPs in order are also described in order to emphasize the importance of PCPs initiating this important conversation. Next, we provide strategies and resources to help guide the PCP in the management of sexual dysfunction in cancer survivors. Finally, we discuss case examples of survivorship sexual health issues and highlight the role that a PCP can play in each of these case examples.  相似文献   
6.
7.
8.
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