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   2595篇
  免费   210篇
  国内免费   30篇
耳鼻咽喉   32篇
儿科学   184篇
妇产科学   50篇
基础医学   323篇
口腔科学   114篇
临床医学   204篇
内科学   504篇
皮肤病学   59篇
神经病学   172篇
特种医学   234篇
外科学   421篇
综合类   44篇
预防医学   144篇
眼科学   63篇
药学   92篇
中国医学   2篇
肿瘤学   193篇
  2023年   18篇
  2022年   19篇
  2021年   29篇
  2020年   19篇
  2019年   19篇
  2018年   50篇
  2017年   57篇
  2016年   54篇
  2015年   77篇
  2014年   102篇
  2013年   131篇
  2012年   97篇
  2011年   76篇
  2010年   106篇
  2009年   119篇
  2008年   83篇
  2007年   95篇
  2006年   96篇
  2005年   68篇
  2004年   78篇
  2003年   71篇
  2002年   62篇
  2001年   48篇
  2000年   56篇
  1999年   76篇
  1998年   119篇
  1997年   108篇
  1996年   114篇
  1995年   78篇
  1994年   85篇
  1993年   50篇
  1992年   36篇
  1991年   45篇
  1990年   31篇
  1989年   46篇
  1988年   44篇
  1987年   46篇
  1986年   48篇
  1985年   40篇
  1984年   20篇
  1983年   16篇
  1982年   24篇
  1981年   19篇
  1980年   20篇
  1979年   11篇
  1977年   13篇
  1976年   17篇
  1975年   16篇
  1973年   9篇
  1971年   10篇
排序方式: 共有2835条查询结果,搜索用时 46 毫秒
81.
Tracheobronchopathia osteochondroplastica (TO) is a rare benign disease characterized by the presence of osseous and cartilaginous submucosal nodules projecting into the tracheobronchial tree. Most cases are asymptomatic and discovered incidentally at post‐mortem. We identified a case of TO on thoracic spiral CT and confirmed the diagnosis on bronchoscopy. This article reviews the imaging characteristics of TO, and shows the 3‐D virtual bronchoscopic and multiplanar reconstruction appearances of TO.  相似文献   
82.
83.
Abstract

This study was designed to determine whether illness during the academic year, when gender and academic readiness are controlled, is the variable accounting for the demonstrated relationship between life change index and subsequent academic performance. A weak though significant inverse association was found between life change and grades: this association persisted even after statistical adjustment for gender, academic readiness, and illness experience. There was no evidence that illness experience mediated the life change-performance relationship. The association was not subject to a threshold effect according to level of life change.  相似文献   
84.
85.
86.
87.
Peripheral mononuclear cells (MNC) collected from 12 healthy donors and 44 leukemic patients at various stages of the disease were tested for natural killer (NK) activity and for their susceptibility to HTLV-I infection in vitro, measured in terms of percentage of p19 positive cells. MNC from leukemic donors at any stage of leukemia (ie, onset or relapse, ON/REL; complete remission or off-therapy, CR/OT donors) were highly susceptible to HTLV-I infection. This was true for acute leukemias of lymphoblastic (ALL) or nonlymphoblastic (ANLL) type. MNC of ON/REL patients were more susceptible to HTLV-I than those of CR/OT donors. In addition, leukemic blasts were more rapidly infected (ie, within five to seven days) than the HTLV-I-susceptible normal cord- blood lymphocytes. However, the presence of circulating blasts was not essential to virus susceptibility, since CR/OT MNC, presumably free of leukemic blasts, were still more susceptible to HTLV-I than normal cells. Basal NK function of MNC from leukemic patients was significantly lower than that detectable in healthy controls. However, no correlation was found between susceptibility to HTLV-I infection and NK activity.  相似文献   
88.

Background:

Monoamine reuptake inhibitors exhibit unique clinical profiles that reflect distinct engagement of the central nervous system (CNS) transporters.

Methods:

We used a translational strategy, including rodent pharmacokinetic/pharmacodynamic modeling and positron emission tomography (PET) imaging in humans, to establish the transporter profile of TD-9855, a novel norepinephrine and serotonin reuptake inhibitor.

Results:

TD-9855 was a potent inhibitor of norepinephrine (NE) and serotonin 5-HT uptake in vitro with an inhibitory selectivity of 4- to 10-fold for NE at human and rat transporters. TD-9855 engaged norepinephrine transporters (NET) and serotonin transporters (SERT) in rat spinal cord, with a plasma EC50 of 11.7ng/mL and 50.8ng/mL, respectively, consistent with modest selectivity for NET in vivo.Accounting for species differences in protein binding, the projected human NET and SERT plasma EC50 values were 5.5ng/mL and 23.9ng/mL, respectively. A single-dose, open-label PET study (4–20mg TD-9855, oral) was conducted in eight healthy males using the radiotracers [11C]-3-amino-4- [2-[(di(methyl)amino)methyl]phenyl]sulfanylbenzonitrile for SERT and [11C]-(S,S)-methylreboxetine for NET. The long pharmacokinetic half-life (30–40h) of TD-9855 allowed for sequential assessment of SERT and NET occupancy in the same subject. The plasma EC50 for NET was estimated to be 1.21ng/mL, and at doses of greater than 4mg the projected steady-state NET occupancy is high (>75%). After a single oral dose of 20mg, SERT occupancy was 25 (±8)% at a plasma level of 6.35ng/mL.

Conclusions:

These data establish the CNS penetration and transporter profile of TD-9855 and inform the selection of potential doses for future clinical evaluation.  相似文献   
89.
90.
Isolated mitochondrial complex IV (cytochrome c oxidase) deficiency is an important cause of mitochondrial disease in children and adults. It is genetically heterogeneous, given that both mtDNA-encoded and nuclear-encoded gene products contribute to structural components and assembly factors. Pathogenic variants within these proteins are associated with clinical variability ranging from isolated organ involvement to multisystem disease presentations. Defects in more than 10 complex IV assembly factors have been described including a recent Lebanese founder mutation in PET100 in patients presenting with Leigh syndrome. We report the clinical and molecular investigation of a patient with a fatal, neonatal-onset isolated complex IV deficiency associated with multiorgan involvement born to consanguineous, first-cousin British Asian parents. Exome sequencing revealed a homozygous truncating variant (c.142C>T, p.(Gln48*)) in the PET100 gene that results in a complete loss of enzyme activity and assembly of the holocomplex. Our report confirms PET100 mutation as an important cause of isolated complex IV deficiency outside of the Lebanese population, extending the phenotypic spectrum associated with abnormalities within this gene.  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