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   460篇
  免费   19篇
  国内免费   18篇
耳鼻咽喉   4篇
儿科学   10篇
妇产科学   5篇
基础医学   70篇
口腔科学   3篇
临床医学   52篇
内科学   101篇
皮肤病学   3篇
神经病学   13篇
特种医学   13篇
外科学   50篇
综合类   63篇
预防医学   41篇
眼科学   1篇
药学   35篇
中国医学   5篇
肿瘤学   28篇
  2023年   3篇
  2022年   8篇
  2021年   11篇
  2020年   7篇
  2019年   6篇
  2018年   8篇
  2017年   18篇
  2016年   12篇
  2015年   13篇
  2014年   30篇
  2013年   42篇
  2012年   19篇
  2011年   37篇
  2010年   32篇
  2009年   25篇
  2008年   30篇
  2007年   21篇
  2006年   19篇
  2005年   17篇
  2004年   16篇
  2003年   15篇
  2002年   10篇
  2001年   12篇
  2000年   12篇
  1999年   8篇
  1998年   6篇
  1997年   7篇
  1996年   5篇
  1995年   2篇
  1994年   5篇
  1993年   6篇
  1992年   3篇
  1991年   3篇
  1990年   3篇
  1989年   2篇
  1988年   6篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   3篇
  1983年   2篇
  1981年   2篇
  1980年   4篇
  1977年   1篇
  1976年   1篇
排序方式: 共有497条查询结果,搜索用时 15 毫秒
71.
The main objective of this investigation was to study the influence of drug dependence on platelet monoamine oxidase (MAO) activity in the presence and absence of alcoholism. One hundred and thirteen admissions to alcohol and drug treatment facilities participated in the study. Twenty-six met the criteria for alcoholism (group I), seventy-eight subjects were alcohol-/cocaine- and cannabis-dependent (group II), and the remaining nine were patients with DSM-III-R diagnosis of cocaine addiction (group III). MAO activity was assayed radiochemically with [14C]tyramine as a substrate (221 μM). The results of this study showed that platelet MAO activity [nmol of product formed x (mg protein)−1 x hr−1] (mean ± SE) was significantly ( p < 0.01) lower in all of these subjects (group 1, 5.50 ± 0.80; group II, 3.90 ± 0.50; group III, 4.3 ± 1.60) as compared with controls (14.85 ± 1.13). Measurements of platelet MAO activity may provide us with a reliable biochemical marker for alcoholism and perhaps addiction to other substances of abuse (i.e., cocaine).  相似文献   
72.
A study of mental retardation in children in the Island of Hawaii   总被引:3,自引:0,他引:3  
Eighty-one probands from an initial population of 223 school-aged retarded individuals were assessed by history, clinical examination and, where appropriate, cytogenetic analysis. In 51 individuals, the retardation occurred as an isolated event within the family, whereas 30 patients had a family history of retardation. In 39 of the isolated individuals, the retardation was either related to environmental factors or associated with a major neurological abnormality. The remaining 12 patients were phenotypically normal with no cytogenetic abnormality. Of the 30 probands from 15 families with a history of retardation, 3 families had X-linked syndromes. One, with 4 proband daughters, had the mar(X) syndrome and two families were considered to have the phenotypically similar syndrome but without demonstrating the mar(X). In an additional 5 families, the distribution and clinical features of the affected individuals were compatible with nonspecific X-linked mental retardation.  相似文献   
73.
OBJECTIVES: Quantitative cytology (Quanticyt) is a valuable marker for the identification of high-risk superficial bladder cancer (SBC) patients and can be used to individualize surveillance of patients. A disadvantage is the necessity to perform an invasive procedure to obtain the required bladder wash sample. This study investigated whether quantitative cytology can be performed on voided urine with reliable results, consistent with the quantitative cytology performed on bladder wash samples. METHODS: Between June 2003 and May 2005, 288 voided urine samples in combination with bladder wash samples were obtained from patients with SBC who visited our urologic outpatient department. Quantitative cytology was performed on all samples. Corresponding clinical pathologic features and washed cytopathology results were collected. Linear regression analyses were performed for comparison of results from both types of samples. RESULTS: Ninety-one percent of the samples fell into the low or intermediate region on bladder wash. A clear deviation in the nuclear shape (MPASS) was seen in the voided urine samples, which led to more low-risk results. The clinical characteristics show that this shift is not the result of under-staging. The nuclear content (2c deviation index [DI]) did not change by performing the analysis on urine. CONCLUSION: When urine is correctly processed after voiding, quantitative cytology can be done on these samples. Voided urine-based quantitative cytology can be implemented in daily practice.  相似文献   
74.
Prenatal differentiation of mouse vomeronasal neurones   总被引:1,自引:0,他引:1  
The vomeronasal organ (VNO) subserves basic chemosensory functions in rodents, mainly related to sexual behaviour. In order to understand early stages of the VNO structural maturation, we have undertaken an immunocytochemical analysis of the VNO of fetal mice. Our results demonstrate that Olfactory Marker Protein (OMP), a marker of differentiated chemosensory cells, is already expressed in vomeronasal neurones and their fibres projecting to the accessory olfactory bulb during the last week of gestation. However, in contrast to the adult, where its expression is restricted to the medial sensory neuronal component of the VNO, during fetal development OMP is also present in cells located in the lateral non-sensory epithelial component. Some other markers of nasal chemosensory neurones, such as GAP-43/B-50, Protein Gene Product 9.5 (PGP 9.5) and carnosine are also transiently expressed in this ectopic site. These results indicate that (i) significant morphological and biochemical maturation of the VNO is achieved before birth; (ii) transient cell populations, sharing the biochemical profile of the vomeronasal chemosensory receptors, occur in ectopic areas during fetal development.  相似文献   
75.
Procalcitonin (PCT) has been described as a marker of bacterial sepsis. However, little is known of its diagnostic value in fungal infections. We calculated the sensitivity of PCT for detection of invasive fungal infections (IFI) by analyzing 55 episodes of proven or probable IFI (three in our series, 52 reported in the recent literature). In the early phase of IFI, PCT was elevated in fewer than half of invasive candidiasis episodes and in only one patient (5.3%) with invasive aspergillosis. Due to low sensitivity and specificity, PCT adds little to the diagnosis of IFI.  相似文献   
76.
髓样细胞触发受体-1是新近发现的免疫球蛋白超家族成员之一.其主要通过与其配体结合被激活后发生交联反应,或者通过增加转录因子的水平,从而激发、放大炎症反应,促进抗炎因子下调.髓样细胞触发受体-1可以看作是诊断感染性疾病的标志物,它的阻断可能成为治疗炎症性疾病的一种新方法.该文对其结构、信号传导、表达、调节以及在临床上的应用进行阐述.  相似文献   
77.
高娅  王婷 《中国科学美容》2011,(17):158-159
目的探讨HBV标志物与HBV-DNA的相关性,更加准确地了解患者HBV感染、病毒复制和传染性情况,为临床制定合理的治疗方案、疗效观察和预后评估提供依据。方法用电化学发光法测定HBV标志物,用实时荧光定量PCR方法检测HBV-DNA。结果 HBV标志物模式1~5均有HBV-DNA阳性检出,其中模式4的检出率最高(81.7%),而且DNA含量也最高;模式6~9均为DNA阴性。在乙肝五项指标中,HBeAg的定量结果与HBV-DNA含量相关性最大(r=0.713)。结论 HBV标志物和HBV-DNA既相关又有所不同,应将两者结合起来并相互补充才能更好的反映患者HBV病毒复制和传染性情况。  相似文献   
78.
AIM:To evaluate the usefulness of differentially expressed proteins from colorectal cancer (CRC) tissues for differentiating cancer and normal tissues.METHODS:A Proteomic approach was used to identify the differentially expressed proteins between CRC and normal tissues.The proteins were extracted using Tris buffer and thiourea lysis buffer (TLB) for extraction of aqueous soluble and membrane-associated proteins,respectively.Chemometrics,namely principal component analysis (PCA) and linear discriminant analy...  相似文献   
79.
Small cell lung cancer (SCLC) is one of the most fatal cancers in humans and many factors are known to be related to its poor prognosis. Immunohistochemical (IHC) stainings were done on SCLC specimens in order to investigate the prognostic value of the apoptosis-related gene expression and the tumor proliferative maker, and the relationships among these IHC results and patients clinical characteristics, chemoresponsiveness, and survival were analyzed. The medical records of 107 patients were reviewed retrospectively. IHC stainings for p53, bcl-2 and Ki-67 expressions were performed in the 66 paraffin-embedded biopsy samples. Sixty-six out of the 107 patients were evaluable for response rate and survival. The overall response rate was 75% (95% Confidence Interval=74-76%) and the median survival time was 14 months. The median survival time of limited stage was 16 months and that of extensive stage was 10 months. The prevalence of p53, bcl-2 and Ki-67 expression was 62%, 70%, and 49%, respectively. There were no correlations among the immunoreactivities of p53, bcl-2 and Ki-67 with clinical stage, chemoresponsiveness or overall survival. The clinical stage was the only prognostic factor influencing survival. The expression rates of p53, bcl-2, and Ki-67 were relatively high in SCLC without any prognostic significance. The exact clinical role of these markers should be defined through further investigations.  相似文献   
80.
BACKGROUND: Alcohol abuse has been shown to result in the production of antibodies against acetaldehyde-modified epitopes in proteins. However, as yet, only limited information has been available on the clinical usefulness of such responses as markers of hazardous drinking. METHODS: We developed an ELISA to measure specific IgAs against acetaldehyde-protein adducts. This method was evaluated in cross-sectional and follow-up studies on male heavy drinkers with a current ethanol consumption of 40 to 540 g/d (n=40), moderate drinkers consuming 1 to 40 g/d (n=25), and abstainers (n=16). The clinical assessments included detailed interviews on the amounts and patterns of ethanol consumption and various biochemical markers of alcohol abuse and liver function. RESULTS: The mean antiadduct IgAs (198+/-28 U/L) in the alcohol abusers were significantly higher than those in the moderate drinkers (58+/-11 U/L, p<0.001) or abstainers (28+/-8 U/L, p<0.001). The values of moderate drinkers were also higher than those in abstainers (p<0.05). The amount of ethanol consumed during the period of 1 month preceding blood sampling correlated strongly with antiadduct IgAs (r=0.67, p<0.001). The sensitivity (73%) and specificity (94%) of this marker were found to exceed those of the conventional laboratory markers of alcohol abuse in comparisons contrasting heavy drinkers with abstainers although not in comparisons contrasting heavy drinkers with moderate drinkers. During abstinence, antiadduct IgAs disappeared with a mean rate of 3% per day. In additional analyses of possible marker combinations, antiadduct IgAs, together with CDT, were found to provide the highest sensitivity and specificity. CONCLUSIONS: Measurements of antiadduct IgAs may provide a new clinically useful marker of alcohol abuse, providing a close relationship between marker levels and the actual amounts of recent ethanol ingestion.  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