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   133篇
  免费   6篇
  2023年   5篇
  2022年   6篇
  2021年   7篇
  2020年   4篇
  2019年   1篇
  2018年   7篇
  2017年   4篇
  2016年   6篇
  2015年   4篇
  2014年   6篇
  2013年   10篇
  2012年   6篇
  2011年   6篇
  2010年   5篇
  2009年   8篇
  2008年   5篇
  2007年   2篇
  2006年   2篇
  2005年   3篇
  2004年   5篇
  2003年   5篇
  2002年   6篇
  2001年   2篇
  1998年   3篇
  1997年   2篇
  1995年   2篇
  1990年   1篇
  1984年   1篇
  1979年   1篇
  1974年   1篇
  1973年   1篇
  1972年   2篇
  1971年   2篇
  1970年   2篇
  1968年   3篇
  1963年   1篇
  1954年   1篇
  1949年   1篇
排序方式: 共有139条查询结果,搜索用时 31 毫秒
71.
Pterostilbene, a methoxylated analogue of resveratrol, is a natural compound primarily found in blueberries and several types of grapes. However, little is known about the effect of pterostilbene on the proliferation of hepatoma cells and its modes of actions. This study was undertaken to characterize its ability to suppress the proliferation of hepatoma AH109A cells and the possible mechanism(s) involved. Pterostilbene showed a significant and dose-dependent effect on the anti-proliferative activity against AH109A cells. Pterostilbene exerted little or no effect on the proliferation of rat L6 myoblasts and rat skin fibroblasts. Pterostilbene-loaded rat sera could significantly inhibit the proliferation of AH109A cells, which suggests that pterostilbene could be absorbed through gastrointestinal tract and retain its anti-proliferative activity. Pterostilbene arrested the cell cycle of AH109A cells at G0/G1 phase and reduced the protein expression of cyclin-dependent kinase 4 and cyclin-dependent kinase 6 dose-dependently. We also found that pterostilbene could significantly increase the intracellular peroxide level of AH109A cells, which may be involved in its anti-proliferative activity.  相似文献   
72.
73.
Anthurium anther culture was successfully established using half-anthers as explants. Explants were cultured on Winarto–Teixeira basal medium (WT-1) containing 0.01 mg/l α-naphthalene acetic acid (NAA), 0.5 mg/l thidiazuron (TDZ), and 1.0 mg/l 6-benzylaminopurine (BAP), or on New Winarto–Teixeira basal medium (NWT-3) supplemented with 0.02 mg/l NAA, 1.5 mg/l TDZ, and 0.75 mg/l BAP for callus initiation. Regenerated calli produced multiple shoots on WT-1, which were then rooted in NWT-3 supplemented with 1% activated charcoal. Plantlets were acclimatized ex vitro using a mixture of burned rice husk, rice husk, and bamboo peat (1:1:1, v/v/v) as the potting medium. There was considerable morphological and cytological diversity of regenerants derived from anther culture, which are described in detail in this study. The callus cluster color ranged from green to light green and had a high regeneration capacity (7.3 and 4.8 shoots/callus cluster), light reddish-yellow callus showed moderate regeneration (2.6 shoots/callus cluster), while reddish-yellow callus had the lowest regeneration capacity (1.5 shoots/callus cluster). Morphological variations clearly observed in regenerants derived from this technique included alterations in plant size, peduncle length, spathe position compared to leaves, the type and number of buds, spathe and spadix color, and spadix length. There were also cytological variations in both in vitro and ex vitro regenerants of anther culture with 23–29% haploids, 5–10% aneuploids, 56–69% diploids, and 3–4% triploids. The results strengthen other studies in which the development of anther cultures, especially via callus formation, resulted in morphological and cytological alterations. These variations have been discussed to great length in this paper.  相似文献   
74.
Study of extraction of astaxanthin from giant tiger (Panaeus monodon) shrimp waste using palm oil was conducted to determine the extraction kinetics and thermodynamic parameters. Two extraction models were proposed: mass transfer kinetic model and reaction kinetic model. It was found that both of mass transfer and reaction kinetic control the extraction of astaxanthin from shrimp waste using palm oil. The thermodynamic parameters of extraction were also obtained in this study.  相似文献   
75.
76.
77.
A simple method of recording the distress of dying patients is described. Significant differences occurred between deaths at home and in hospital for three factors. Patients dying at home were (a) more likely to be fully alert shortly before death (P < 0·05); (b) less likely to be suffering from vomiting, incontinence, or bedsores (P < 0·001); and (c) less likely to have unrelieved physical distress (P < 0·05). No significant differences occurred in the distress of patients dying in general-practitioner compared with other hospitals, though the numbers compared were small and a larger study might prove useful.  相似文献   
78.
79.

Background

Identification of dengue patients at risk for progressing to severe disease is difficult. Significant plasma leakage is a hallmark of severe dengue infection which can suddenly lead to hypovolemic shock around the time of defervescence. We hypothesized that the detection of subclinical plasma leakage may identify those at risk for severe dengue. The aim of the study was to determine the predictive diagnostic value of serial ultrasonography for severe dengue.

Methodology/Principal Findings

Daily bedside ultrasounds were performed with a handheld ultrasound device in a prospective cohort of adult Indonesians with dengue. Timing, localization and relation to dengue severity of the ultrasonography findings were determined, as well as the relation with serial hematocrit and albumin values. The severity of dengue was retrospectively determined by WHO 2009 criteria. A total of 66 patients with proven dengue infection were included in the study of whom 11 developed severe dengue. Presence of subclinical plasma leakage at enrollment had a positive predictive value of 35% and a negative predictive value of 90% for severe dengue. At enrollment, 55% of severe dengue cases already had subclinical plasma leakage, which increased to 91% during the subsequent days. Gallbladder wall edema was more pronounced in severe than in non-severe dengue patients and often preceded ascites/pleural effusion. Serial hematocrit and albumin measurements failed to identify plasma leakage and patients at risk for severe dengue.

Conclusions/Significance

Serial ultrasonography, in contrast to existing markers such as hematocrit, may better identify patients at risk for development of severe dengue. Patients with evidence of subclinical plasma leakage and/or an edematous gallbladder wall by ultrasonography merit intensive monitoring for development of complications.  相似文献   
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