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   492篇
  免费   35篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   8篇
妇产科学   6篇
基础医学   63篇
口腔科学   40篇
临床医学   54篇
内科学   105篇
皮肤病学   6篇
神经病学   29篇
特种医学   22篇
外科学   78篇
综合类   14篇
一般理论   1篇
预防医学   16篇
眼科学   7篇
药学   26篇
中国医学   7篇
肿瘤学   42篇
  2024年   1篇
  2023年   8篇
  2022年   20篇
  2021年   26篇
  2020年   22篇
  2019年   16篇
  2018年   27篇
  2017年   16篇
  2016年   12篇
  2015年   16篇
  2014年   27篇
  2013年   40篇
  2012年   45篇
  2011年   41篇
  2010年   27篇
  2009年   15篇
  2008年   18篇
  2007年   21篇
  2006年   23篇
  2005年   29篇
  2004年   21篇
  2003年   14篇
  2002年   8篇
  2001年   4篇
  2000年   2篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1985年   1篇
  1983年   1篇
  1979年   1篇
  1978年   1篇
  1963年   1篇
排序方式: 共有528条查询结果,搜索用时 78 毫秒
1.
2.
A group of pregnant mothers above 35 years old were collected from the MCH centre in Kafr-El Zayat during a period of 10 months (82). A control group of mothers aged 20-30 years old were also selected during the same period (62). Those with specific diseases from both groups were excluded. During the repeated visits of those mothers to the MCH centre they were subjected to complete history taking, physical examination plus urine analysis & haemoglobin levelling. A special visit was performed by the researcher to the mothers on 7th day after labour to report on the outcome of labour. The present study revealed significant differences between mothers over 35 years and those of 20-30 years in the course of pregnancy, labour and their outcomes where the former group showed greater tendency to be at a higher risk.  相似文献   
3.

Purpose  

The aim of this study was to investigate current prescribing and dispensing practices at primary healthcare centers in Kuwait and compare them with those reported in other countries.  相似文献   
4.
Von Hlppel—Lindau (VHL) disease is a dominantly Inheritedfamillal cancer syndrome In which affected individuals havea greatly increased predisposition to the development of haemangloblastomasof the central nervous system and retina, renal cell carcinomaand phaeochromocytoma. The VHL gene has been mapped to chromosome3p25 -p26 by genetic linkage studies and we have previouslydemonstrated that the VHL gene is tightly linked to the D3S601locus (Zmax = 18.86 at  相似文献   
5.
Tuberous sclerosis complex (TSC) and Peutz-Jeghers syndrome (PJS) are dominantly inherited benign tumor syndromes that share striking histopathological similarities. Here we show that LKB1, the gene mutated in PJS, acts as a tumor suppressor by activating TSC2, the gene mutated in TSC. Like TSC2, LKB1 inhibits the phosphorylation of the key translational regulators S6K and 4EBP1. Furthermore, we show that LKB1 activates TSC2 through the AMP-dependent protein kinase (AMPK), indicating that LKB1 plays a role in cell growth regulation in response to cellular energy levels. Our results suggest that PJS and other benign tumor syndromes could be caused by dysregulation of the TSC2/mTOR pathway.  相似文献   
6.
Zusammenfassung Mit Krebs-Ringerlösung durchströmte Rattenherzen geben um so weniger Kreatin an die Durchströmungsflüssigkeit ab, je schonender sie präpariert wurden.Nach Zugabe von 3 mg bzw. 5 mg Kreatin zu 100 ml Durchstrom nahmen die meisten Herzen innerhalb von 30 min 400 bzw. 830 Kreatin/g Trockengewicht auf. Weitere Steigerung des Kreatinangebotes verbesserte die Kreatinaufnahme nicht, ebensowenig wie Zugabe von Glucose. Enthielt der Durchstrom Insulin, so wurde die Kreatinaufnahme signifikant erhöht.Die Mehrzahl der mit Kreatin durchströmten Herzen nahm aus der Krebs-Ringerlösung Phosphat auf.Kalium wurde von einigen Herzen abgegeben, von anderen aufgenommen. Die Kaliumaufnahme aus dem Durchstrom war bei geschädigten Herzen am größten. Zusammenhänge zwischen dem Verhalten von Kalium einerseits und Kreatin oder Phosphat andererseits wurden in den Versuchen an isolierten Herzen nicht erkennbar.
Summary Rat hearts perfused with Krebs' Ringer solution, yielded creatine in the perfusion fluid; the more carefully the hearts were dissected, the smaller was the yield.When creatine was added to the perfusion fluid in concentrations of 3 or 5 mg-%, the hearts took up creatine in most cases to the extent of 400g or 830µg respectively, per g dry weight. A further increase in the creatine concentration did not improve the creatine uptake, nor did an addition of glucose to the perfusion fluid. When the latter contained insulin, the creatine uptake was significantly increased.The majority of the creatine-perfused hearts took up phosphate from the Krebs' Ringer solution.During perfusion some of the hearts yielded potassium, others took up potassium. The potassium uptake was greatest with hearts which had been damaged during the dissection. No connection could be observed in the experiments with isolated hearts between the behaviour of potassium on the one hand, and that of creatine or phosphate on the other.


Ausgeführt mit Unterstützung des Landes Nordrhein-Westfalen (Landesamt für Forschung).

Herrn Prof. Dr.E. Lehnartz zum 65. Geburtstag.  相似文献   
7.
VHL disease is a dominantly inherited familial cancer syndromewith variable expression and age-dependent penetrance. The diagnosisof isolated cases is often delayed compared with familial cases,and estimates of the new mutation rate have varied more than20-fold. To investigate the frequency and origin of de novoVHL gene mutations we have analysed: (i) families with identicalmutations to determine if there is a common haplotype, and (ii)apparent new mutation cases to determine whether the clinicaldiagnosis of such cases is reliable and to define the parentalorigin of de novo VHL gene mutations. Haplotyping of 12 VHLmutations occurring in two or more families (total 42 kindreds)revealed that for most mutations there was no evidence of afounder effect. A marked bias for a paternal origin of new mutationshas been reported in other familial cancer syndromes such asneurofibromatosis type 1 (NF1), multiple endocrine neoplasia(MEN) 2B and bilateral retinoblastoma, but it is unclear whetherthis bias results from a greater susceptibility for mutagenesisduring male gametogenesis because of the larger number of celldivisions compared with that in oogenesis, or from genomic imprintingeffects. Analysis of 13 de novo VHL mutations in which the parentof origin could be established, showed no evidence for a biasfor a paternal origin (seven paternal, six maternal), and differedsignificantly from that reported in NF1, MEN2B and bilateralretinoblastoma. This result demonstrates that an increased susceptibilityto paternal allele mutation is not a universal finding in autosomalgenetic diseases and that the origin of new mutations may beinfluenced by both genomic imprinting effects and the increasednumber of cell divisions in spermatogenesis compared with oogenesis.  相似文献   
8.
The ApoE4 allele is the most well-studied genetic risk factor for Alzheimer’s disease, a condition that is increasing in prevalence and remains without a cure. Precision nutrition targeting metabolic pathways altered by ApoE4 provides a tool for the potential prevention of disease. However, no long-term human studies have been conducted to determine effective nutritional protocols for the prevention of Alzheimer’s disease in ApoE4 carriers. This may be because relatively little is yet known about the precise mechanisms by which the genetic variant confers an increased risk of dementia. Fortunately, recent research is beginning to shine a spotlight on these mechanisms. These new data open up the opportunity for speculation as to how carriers might ameliorate risk through lifestyle and nutrition. Herein, we review recent discoveries about how ApoE4 differentially impacts microglia and inflammatory pathways, astrocytes and lipid metabolism, pericytes and blood–brain barrier integrity, and insulin resistance and glucose metabolism. We use these data as a basis to speculate a precision nutrition approach for ApoE4 carriers, including a low-glycemic index diet with a ketogenic option, specific Mediterranean-style food choices, and a panel of seven nutritional supplements. Where possible, we integrate basic scientific mechanisms with human observational studies to create a more complete and convincing rationale for this precision nutrition approach. Until recent research discoveries can be translated into long-term human studies, a mechanism-informed practical clinical approach may be useful for clinicians and patients with ApoE4 to adopt a lifestyle and nutrition plan geared towards Alzheimer’s risk reduction.  相似文献   
9.
IntroductionPeriodontal mechanoreceptors (PMRs) are refined neural receptors present in abundance at the root apex and have a pivotal role in oral fine motor control. This case-control study aimed to evaluate the oral fine motor control of teeth treated with endodontic microsurgery (EMS) in comparison with the control teeth using a standardized behavioral biting task.MethodsFourteen eligible participants performed 5 trials of an oral fine motor control task that involved holding and splitting half of a peanut positioned on a force transducer with their EMS treated tooth and its contralateral control incisor tooth (28 teeth in total). The outcome variables were the mean food holding force, intra- and intertrial variability of the holding force, food splitting force, splitting duration, and the frequency of the stepwise splitting phase. The data were analyzed with parametric and nonparametric tests.ResultsThe results showed no statistically significant differences in the holding force, inter- and intratrial variability of the holding force, splitting force, or splitting duration between the teeth treated with EMS and the control (P > .05). However, there was a significantly higher frequency of stepwise ramp increase during the splitting phase with EMS treated teeth compared with the control (48% and 37%, respectively; P < .05).ConclusionsEMS treated teeth showed similar force regulation and oral fine motor control as the contralateral control. The findings of this study suggest that EMS treatment does not perturb the sensory information of PMRs and maintains the force regulation and oral fine motor control of the teeth.  相似文献   
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