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   1416篇
  免费   60篇
  国内免费   4篇
耳鼻咽喉   4篇
儿科学   23篇
妇产科学   40篇
基础医学   128篇
口腔科学   24篇
临床医学   156篇
内科学   333篇
皮肤病学   24篇
神经病学   85篇
特种医学   50篇
外科学   265篇
综合类   2篇
预防医学   60篇
眼科学   62篇
药学   80篇
中国医学   4篇
肿瘤学   140篇
  2023年   8篇
  2022年   39篇
  2021年   51篇
  2020年   32篇
  2019年   39篇
  2018年   56篇
  2017年   39篇
  2016年   24篇
  2015年   37篇
  2014年   57篇
  2013年   76篇
  2012年   112篇
  2011年   116篇
  2010年   59篇
  2009年   63篇
  2008年   87篇
  2007年   76篇
  2006年   75篇
  2005年   75篇
  2004年   67篇
  2003年   83篇
  2002年   67篇
  2001年   14篇
  2000年   11篇
  1999年   9篇
  1998年   7篇
  1997年   12篇
  1996年   5篇
  1995年   6篇
  1994年   3篇
  1993年   2篇
  1992年   4篇
  1991年   10篇
  1990年   14篇
  1989年   4篇
  1987年   2篇
  1986年   4篇
  1985年   5篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1981年   2篇
  1979年   2篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1972年   1篇
  1971年   5篇
  1937年   1篇
  1914年   1篇
排序方式: 共有1480条查询结果,搜索用时 62 毫秒
1.
Purpose:This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration.Methods:Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter.Results:There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p < 0.05.Conclusions:Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.Key words: Bone Regeneration, Platelet-Rich Plasma, Tissue Engineering, Rats  相似文献   
2.
3.
Apoptosis is an essential ubiquitous process that controls the duration of the life span of cells, thus playing a crucial role in morphogenetic, histogenetic, and phylogenetic developmental processes. Apaf1 (apoptosis protease activating factor 1) is one of the central mediators of the intrinsic apoptotic pathway and a part of the apoptosome, which activates procaspase-3 and promotes cell death. Gene knockout of Apaf1 in mice leads to late embryonic lethality with malformations such as the persistence of interdigital webs and hyperplasia of brain and retina. Therefore, Apaf1 is generally believed to play a crucial role in developmental apoptosis and have a widespread expression. However, its pattern of expression in early development remains unknown. To specify whether Apaf1 indeed plays this key role, we investigated the pattern of gene expression for Apaf1 in mouse embryos on day 7, 9, and 12 of development. Our results show, that gene expression for Apaf1 first occurs within the embryo between day 7 and 9 of development, becoming more widespread toward day 12 and then includes structures, such as yolk sac, mesenchyme, cartilage, heart anlage, otic vesicle, peridermis, and anlagen of the spinal ganglia and vertebral bodies. Our results also show that gene expression for Apaf1 is not ubiquitous in early mouse development. This finding indicates that cell death processes are independent of or less dependent on Apaf1 during this time. Of interest, an active gene expression for Apaf1 is also present in organ anlagen such as heart or intestine, in which no obvious phenotype is seen after Apaf1 deletion. This finding suggests a possible role for Apaf1 in such anlagen as a putative alternative compensatory pathway, which could be switched on in the case of defects in the mediators that are normally involved in such organs.  相似文献   
4.
5.
The assessment, treatment, and prevention of pediatric pain pose a special challenge to surgeons and others involved in the care of children. The experience of pain is subjective, and infants and many children are unable to verbalize their level of discomfort. Therefore, it is the responsibility of physicians and nurses to be educated and trained to identify nonverbal signs of pain and discomfort, anticipate the experience of pain associated with specific procedures and diagnoses, and initiate the appropriate use of analgesics as well as nonmedicinal strategies to relieve this pain.  相似文献   
6.
7.
Soluble and phagocytic stimuli released PAF-acether from PMN leucocytes, as determined by chromatography and bioassay by platelet aggregation. The same material caused aggregation of human and rabbit PMN leucocytesin vitro which was inhibited by ETYA and PGI2. PGI2 also inhibited PAF-acether release by PMN leucocytes and,in vivo, PGI2 abolished not only PAF-acether-induced, but also immune complex or C5a-induced thrombocytopenia and neutropenia in rabbits. These data suggest that PAF-acether may be involved in activation of both platelets and PMN leucocytesin vivo.  相似文献   
8.
The overall prevalence of anti-HCV antibody in a group of 125 haemophiliacs was 62%. Four patients who had never received replacement therapy were anti-HCV negative. Of the 121 patients injected regularly with commercial concentrates, 76 were already anti-HCV seropositive in 1985 and remained so throughout the follow-up. Two patients seroconverted in 1987 without obvious signs or symptoms of hepatitis. Our patients were treated with dry heat-treated concentrates since 1985 and with wet heat- or solvent/detergent-treated concentrates since 1988. The absence of further seroconversions and of symptoms of acute post-transfusion non-A, non-B hepatitis since 1988 suggest that present virucidal treatments of concentrates are effective in preventing HCV transmission. Anti-HCV positivity appeared to be unrelated to the type and degree of haemophilia as well as to the presence of antibodies to hepatitis B virus, human immunodeficiency virus type 1, and human herpesvirus type 6.  相似文献   
9.
At the current epidemic stage, characterized by the rise of antiretroviral drug resistance, it is necessary to administer to HIV-positive patients increasingly effective treatments. This is possible only by means of powerful drugs. In a retrospective study, the authors evaluate 78 patients: 76 pre-treated with multiple drugs and 2 na ves. The 78 patients received LPV/RTV, starting from the fourth 3-month period of 2000 until the first 3-month period of 2002. The average treatment duration was 6.5 ( 5.5) months; the median value 6 months. The efficacy of the LPV/RTV therapeutic regimen was evaluated by a cytofluorimetric count of CD4+ and determination of the HIV viral load. There were 14 drop-out patients (17.9%): 5 because of auto-suspension, 1 due to absence of clinical and virological efficacy, 5 due to side effects (3 hepatopathy, 1 allergy and 1 nausea); three patients were lost on follow-up. There were 64 (82.1%) patients on treatment. Forty patients responded (51.3%) and 13 (16.7%) had uncontrolled viraemia (over than 200 copies/ml). However, the treatment with LPV/RTV was not interrupted for these patients, because in the follow-up they showed an increase in CD4+ values. The authors conclude that the LPV/RTV combination confirms previous findings: it is a drug with a relatively low incidence of side effects, capable of powerful results even in the treatment of patients receiving multiple drugs and thus subjected to the risk of developing antiretroviral drug resistance.  相似文献   
10.
Maternal and Child Health Journal - To study the relationship between cesarean Delivery (CD) and overweight in preschool children, considering the presence of birth aspects and demographic...  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