首页 | 官方网站   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   1170篇
  免费   65篇
  国内免费   6篇
医药卫生   1241篇
  2023年   7篇
  2022年   14篇
  2021年   39篇
  2020年   11篇
  2019年   25篇
  2018年   31篇
  2017年   18篇
  2016年   18篇
  2015年   22篇
  2014年   30篇
  2013年   37篇
  2012年   74篇
  2011年   73篇
  2010年   32篇
  2009年   46篇
  2008年   66篇
  2007年   51篇
  2006年   63篇
  2005年   54篇
  2004年   39篇
  2003年   39篇
  2002年   48篇
  2001年   40篇
  2000年   28篇
  1999年   27篇
  1998年   19篇
  1997年   11篇
  1996年   10篇
  1995年   7篇
  1994年   13篇
  1993年   8篇
  1992年   32篇
  1991年   30篇
  1990年   21篇
  1989年   13篇
  1988年   13篇
  1987年   9篇
  1986年   9篇
  1985年   12篇
  1984年   5篇
  1982年   9篇
  1978年   9篇
  1974年   5篇
  1973年   4篇
  1972年   5篇
  1971年   5篇
  1970年   7篇
  1969年   7篇
  1968年   6篇
  1966年   5篇
排序方式: 共有1241条查询结果,搜索用时 0 毫秒
1.
We report our experience of pediatric liver transplantation with partial grafts from non-heart beating donors (NHBD). Controlled donors less than 40 years of age with a warm ischemia time (WI) of less than 30 min were considered for pediatric recipients. Death was declared 5 min after asystole. A super-rapid recovery technique with aortic and portal perfusion was utilized. Mean donor age was 29 years and WI 14.6 min (range 11–18). Seven children, mean age 4.9 years (0.7–11), median weight 20 kg (8.4–53) received NHBD segmental liver grafts. Diagnoses included seronegative hepatitis, neonatal sclerosing cholangitis, familial intrahepatic cholestasis, hepatoblastoma, primary hyperoxaluria and factor VII deficiency (n = 2).The grafts included four reduced and one split left lateral segments, one left lobe and one right auxiliary graft. Mean cold ischemia was 7.3 h (6.2–8.8). Complications included one pleural effusion and one biliary collection drained percutaneously. At 20 months (10–36) follow-up all children are alive and well with functioning grafts.
Donation after cardiac death is a significant source of liver grafts for adults and children with careful donor selection and short cold ischemic times.  相似文献   
2.
Nonmotor symptoms (NMS) of Parkinson's disease (PD) are not well recognized in clinical practice, either in primary or in secondary care, and are frequently missed during routine consultations. There is no single instrument (questionnaire or scale) that enables a comprehensive assessment of the range of NMS in PD both for the identification of problems and for the measurement of outcome. Against this background, a multidisciplinary group of experts, including patient group representatives, has developed an NMS screening questionnaire comprising 30 items. This instrument does not provide an overall score of disability and is not a graded or rating instrument. Instead, it is a screening tool designed to draw attention to the presence of NMS and initiate further investigation. In this article, we present the results from an international pilot study assessing feasibility, validity, and acceptability of a nonmotor questionnaire (NMSQuest). Data from 123 PD patients and 96 controls were analyzed. NMS were highly significantly more prevalent in PD compared to controls (PD NMS, median = 9.0, mean = 9.5 vs. control NMS, median = 5.5, mean = 4.0; Mann-Whitney, Kruskal-Wallis, and t test, P < 0.0001), with PD patients reporting at least 10 different NMS on average per patient. In PD, NMS were highly significantly more prevalent across all disease stages and the number of symptoms correlated significantly with advancing disease and duration of disease. Furthermore, frequently, problems such as diplopia, dribbling, apathy, blues, taste and smell problems were never previously disclosed to the health professionals.  相似文献   
3.
Wilson's disease (WD) is a rare liver-based disorder of copper metabolism. Prognostic criteria described by our group in 1986 to predict death without transplantation have not been universally validated. The clinical features of 88 children were reviewed, retrospectively in 74 and prospectively in 14. Data from the retrospectively recruited patients that died or survived on long-term chelation were used to evaluate the validity of our old scoring system and to devise a new prognostic index, then assessed in the 14 prospectively recruited patients. Using the old scoring system, 5 children scoring > or = 7, the cutoff value for death without transplantation, survived, whereas 4 scoring < or = 7 died (sensitivity 87% and specificity 90%). A new index based on serum bilirubin, international normalized ratio, aspartate aminotransferase (AST), and white cell count (WCC) at presentation identified a cutoff score of 11 for death and proved to be 93% sensitive and 98% specific, with a positive predictive value of 88%. When the new index was evaluated prospectively in 14 patients, it predicted the need for transplantation in only the 4 who required it, although 1 child with a score of 11 survived on medical treatment. In conclusion, the new Wilson Index is more sensitive and specific in predicting mortality without transplantation than the old scoring system, but needs to be validated in a larger number of patients.  相似文献   
4.
5.
6.
Preventive and therapeutic role of vitamin E in chronic plumbism   总被引:1,自引:0,他引:1  
The ability of vitamin E to prevent or treat experimental lead intoxication was investigated in rats. Lead ingestion (10 mg/kg, lead as lead acetate, orally for 6 weeks) significantly inhibited the activity of blood delta-aminolevulinic acid dehydratase (ALAD), reduced the brain dopamine (DA) contents, enhanced the blood zinc protoporphyrin, and enhanced the urinary excretion of delta-aminolevulinic acid (ALA). Lead exposure also elevated brain norepinephrine, homovanillic acid, and 5-hydroxyindole acetic acid (5-HIAA) levels and concentration of lead in blood and tissue. Simultaneous supplementation of vitamin E along with lead significantly reduced the inhibition of blood ALAD activity, brain DA and 5-HIAA levels, and elevation of urinary ALA excretion. Blood and liver lead concentrations were also significantly reduced by simultaneous supplementation with vitamin E. Postlead exposure treatment with vitamin E was ineffective in reducing the lead-induced effects, except that the inhibition of blood ALAD activity was slightly reduced. The present results suggest that vitamin E given simultaneously with lead is effective in reducing the severity of lead intoxication.  相似文献   
7.
8.
The role of calcium ions (Ca2+) in the cytotoxic activity of the dengue type 2 virus (DV)-induced macrophage (M phi) cytotoxin (CF2) was investigated in the present study. The findings show that CF2 prepared in Ca(2+)-free medium had no cytotoxic activity on normal mouse spleen cells suspended in Ca(2+)-free medium but killed the cells suspended in the medium with Ca2+. Substitution with calcium chloride restored the cytotoxic activity of CF2 the optimal dose being 10(-4) M concentration. CF2 induced an influx of Ca2+, as assayed by uptake of radiolabelled calcium chloride (45Ca), in the susceptible target cells, viz. M phi and T lymphocytes. The cytotoxic activity of CF2 as well as the CF2-induced influx of 45Ca was inhibited by treatment of the target cell with the calcium channel blocking drugs verapamil and nifedipine. Thus, the presence of Ca2+ is obligatory for the cytotoxic activity of CF2 and cell death is associated with increased intracellular Ca2+.  相似文献   
9.
For most experimental and therapeutic applications of gene transfer, regulation of the timing and level of gene expression is preferable to constitutive gene expression. Among the systems that have been developed for pharmacologically controlled gene expression in mammalian cells, the bacterial tetracycline (tet)-responsive system has the advantage that it is dependent on a drug (tet) that is both highly specific and non-toxic. The tet-responsive system has been previously used to modulate expression of cell cycle regulatory proteins in cultured cells, reporter genes in plants and transgenic mice and reporter genes directly injected into the heart. Here we show that orally or parenterally administered tet regulates expression of tet-responsive plasmids injected directly into mouse skeletal muscle. Reporter gene expression was suppressed by two orders of magnitude in the presence of tet, and that suppression was reversed when tet was withdrawn. These data show that skeletal muscle offers an accessible and well characterized target tissue for tet-controlled expression of genesin vivo, suggesting applications to developmental studies and gene therapy.  相似文献   
10.
It has been suggested that humans are genetically restricted from making IgG4 antibody responses to carbohydrate antigens. To test this hypothesis we examined sera from 35 patients with bancroftian filariasis (an infection known to induce very high levels of IgG4 antibodies to the parasite and known to be associated with repeated streptococcal infections) as well as from 15 normal individuals for their IgG and IgG subclass responses to streptococcal protein [streptolysin-O (SO), deoxyribonuclease B (DB)] and carbohydrate [group A carbohydrate (GAC)] antigens. Levels of IgG antibodies to all three antigens were found to be significantly higher in the filariasis patients compared to normals (P less than 0.01), and the subclass composition of these antibodies proved heterogenous. Although responses to all three antigens included IgG1, IgG2 and IgG3 antibodies and although IgG4 responses to the proteins SO and DB were significantly higher in the filariasis patients than in normals (P less than 0.001), more importantly there were no detectable anti-GAC IgG4 antibodies in either study group. These observations, coupled with our earlier finding of the absence of IgG4 responses to phosphocholine (PC) in patients with lymphatic filariasis, suggest that even the chronic antigenic stimulation of filarial helminth infection, which leads to very prominent IgG4 responses to protein antigens, cannot overcome the genetic restriction in humans for making IgG4 antibodies to carbohydrate antigens, whether of parasite or non-parasite origin.  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-23

京公网安备 11010802026262号