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   1015篇
  免费   68篇
  国内免费   8篇
耳鼻咽喉   12篇
儿科学   51篇
妇产科学   14篇
基础医学   144篇
口腔科学   28篇
临床医学   131篇
内科学   226篇
皮肤病学   8篇
神经病学   72篇
特种医学   76篇
外国民族医学   3篇
外科学   117篇
综合类   6篇
预防医学   52篇
眼科学   18篇
药学   95篇
肿瘤学   38篇
  2022年   6篇
  2021年   16篇
  2019年   15篇
  2018年   27篇
  2017年   10篇
  2016年   8篇
  2015年   20篇
  2014年   24篇
  2013年   39篇
  2012年   46篇
  2011年   60篇
  2010年   28篇
  2009年   30篇
  2008年   50篇
  2007年   48篇
  2006年   49篇
  2005年   37篇
  2004年   56篇
  2003年   32篇
  2002年   36篇
  2001年   23篇
  2000年   26篇
  1999年   34篇
  1998年   19篇
  1997年   8篇
  1996年   11篇
  1995年   10篇
  1994年   19篇
  1993年   20篇
  1992年   17篇
  1991年   16篇
  1990年   13篇
  1989年   20篇
  1988年   18篇
  1987年   20篇
  1986年   14篇
  1985年   17篇
  1984年   12篇
  1983年   22篇
  1982年   11篇
  1981年   13篇
  1980年   8篇
  1978年   6篇
  1976年   8篇
  1975年   11篇
  1974年   8篇
  1973年   8篇
  1972年   6篇
  1970年   5篇
  1968年   5篇
排序方式: 共有1091条查询结果,搜索用时 15 毫秒
31.
We have studied 33 patients with a large ventricular aneurysm complicating an anterior myocardial infarction. The features of myocardial infarction progressing towards an aneurysm were no previous history of coronary disease, severe infarction as shown by the severity of pain and the presence of pericardial rub and heart failure, and large increase in serum levels of cardiac enzymes. A large aneurysm usually follows a large infarction resulting from the total or partial occlusion of the left anterior descending artery, which is involved alone in about half the patients and is associated with lesions of the circumflex and right coronary arteries in the other half. In most cases, standard radiography showed an abnormal cardiac configuration, but in 7 patients (21%) there was no radiological evidence of aneurysm. ST segment elevation (mean 2.7 mm) was reported in all subjects but one. Heart failure was present in most patients and was an indication for surgical treatment in one-third of the patients. A large aneurysm was not a contraindication to operation even when at angiography the aneurysm seemed to occupy almost all the left ventricle. Twenty-one patients were operated upon for resection of the aneurysm with a mortality rate of 14 per cent.  相似文献   
32.
CALLA-positive myeloma: an aggressive subtype with poor survival   总被引:5,自引:0,他引:5  
Durie  BG; Grogan  TM 《Blood》1985,66(1):229-232
Detailed immunotyping was carried out on 21 direct myeloma bone marrow aspirates and eight human myeloma cell lines. Four previously untreated common acute lymphoblastic leukemia antigen (CALLA)-positive myeloma patients were identified and six of eight cell lines (75%) were also positive. CALLA positivity, as part of an immature B phenotype, was found to correlate with very aggressive clinical disease: median survival six months v 56 months for the CALLA-negative group.  相似文献   
33.
We here describe 13 patients with non-Hodgkin's lymphoma (NHL) and a translocation t(11:14)(q13:q32). They were part of a series of 163 patients with NHL and an abnormal karyotype, serially referred to our institution between January 1984 and 1990. Patients with t(11:14) seem to present several common and interesting features. Males are more frequently affected than females, and old people more than young. They present at diagnosis with advanced disease and usually show involvement of epithelium and bone marrow. With respect to histologic diagnoses, these patients are usually considered to be of low-grade malignancies. However, most of them do very poorly, have short complete remission and frequent relapses whatever the treatment. As a whole, the median survival rate is rather low. The cytologic, histologic as well as the immunologic patterns tend to be uniform: tumours are composed of small cells and display features of mantle zone/intermediate lymphocytic lymphoma. They express high IgM and low IgD levels and more commonly bear Ig lambda light chains. They also express all pan-B antigens (except CD23) as well as the CD5 antigen, but usually lack the CD10. According to these characteristics, these tumours could be placed in between lymphocytic lymphomas (which usually express CD23) and follicular lymphomas (which commonly lack IgD and CD5 and bear CD10 as well as a t(14:18).  相似文献   
34.
Shih  YJ; Baynes  RD; Hudson  BG; Cook  JD 《Blood》1993,81(1):234-238
To characterize the nature of the immunoreactive transferrin receptor in human serum, antisera were developed to peptide sequences of the extracellular domain of human transferrin receptor between amino acids 107 and 120 and the intracellular domain between amino acids 40 and 54. Antisera against the extracellular domain exhibited reactivity against both purified intact receptor and immunopurified circulating receptor, whereas antisera against the intracellular domain reacted only with intact receptor. Using competitive binding enzyme-linked immunosorbent assays, transferrin receptor in ultracentrifuged sera from normal subjects and patients with sickle cell anemia could be detected with antisera against the extracellular but not the intracellular domain. When the pellet obtained by ultracentrifugation of these sera was assayed after solubilization in 1% teric (polyoxyethylene-9-lauryl ether), only 0.6% of total serum receptor was detected in normal subjects and 3.8% in subjects with sickle cell disease. Roughly equal amounts of this pelleted immunoactivity were detected with antibodies against the extracellular and intracellular domains. These results indicate that less than 1% of transferrin receptor in normal human sera is intact receptor consistent with an exosomal origin and that virtually all circulating transferrin receptor is in the form of a truncated extracellular domain.  相似文献   
35.
Glutamate transporters (excitatory amino-acid transporters (EAATs)) are essential for brain homeostasis. While previous studies indicate that the vascular endothelium contributes to glutamate efflux in the adult brain, little information is available regarding glutamate uptake in the immature brain. The present study shows a differential expression pattern of EAATs between cortical microvessels in adults and newborns. In addition, adult cortical endothelial cells take up glutamate more efficiently than neonatal cells. Our findings indicate age-specific changes in extracellular glutamate regulation by brain endothelial cells, suggesting differences in the efficiency of glutamate efflux during an excitotoxic process that, in turn, may contribute to age-specific brain vulnerability.  相似文献   
36.
Preterm birth is a high‐risk factor for the development of gray and white matter abnormalities, referred to as “encephalopathy of prematurity,” that may lead to life‐long motor, cognitive, and behavioral impairments. The prevalence and clinical outcomes of encephalopathy of prematurity differ between sexes, and elucidating the underlying biological basis has become a high‐priority challenge. Human studies are often limited to assessment of brain region volumes by MRI, which does not provide much information about the underlying mechanisms of lesions related to very preterm birth. However, models using KO mice or pharmacological manipulations in rodents allow relevant observations to help clarify the mechanisms of injury sustaining sex‐differential vulnerability. This review focuses on data obtained from mice aged P1–P5 or rats aged P3 when submitted to cerebral damage such as hypoxia‐ischemia, as their brain lesions share similarities with lesion patterns occurring in very preterm human brain, before 32 gestational weeks. We first report data on the mechanisms underlying the development of sexual brain dimorphism in rodent, focusing on the hippocampus. In the second part, we describe sex specificities of rodent models of encephalopathy of prematurity (RMEP), focusing on mechanisms underlying differences in hippocampal vulnerability. Finally, we discuss the relevance of these RMEP. Together, this review highlights the need to systematically search for potential effects of sex when studying the mechanisms underlying deficits in RMEP in order to design effective sex‐specific medical interventions in human preterms.  相似文献   
37.
38.
39.
Carnitine palmitoyltransferase deficiency realizes two distinct clinical forms. We previously showed and confirmed in the present work that CPTII (identified as the carnitine palmitoyltransferase activity assayable in detergent conditions) is decreased in the muscular form whereas it is unaffected and CPTI is decreased in the hepatic form. The antibody previously prepared against human liver mitochondrial CPTII recognizes the same enzyme in muscle, liver, and fibroblasts. Immunoprecipitation experiments were performed in fibroblasts from patients with the muscular and hepatic forms of the defect. As compared with controls, cell lines from two patients with the hepatic form of the defect did not exhibit any qualitative nor quantitative abnormality of cross-reacting material, whereas cell lines from two patients with the muscular form of the defect exhibited a decreased amount of cross-reacting material. These data suggest that CPTII deficiency could result from a decreased production of protein. The amount of cross-reacting material in the two sets of patients only correlates with CPTII activity, which is decreased in the muscular presentation and unaffected in the hepatic form. These results strengthen the hypothesis of distinct proteins supporting CPTI and CPTII activities.  相似文献   
40.
Effective adjunctive therapies for colorectal carcinoma are clearly needed. We evaluated the cytotoxic responses in vitro of human colon carcinoma cell lines to combined modalities: 5-fluorouracil/leucovorin (5-FU/LV), carboplatin (CP), tumor necrosis factor (TNF) and hyperthermia (HTX). Cytotoxicity was evaluated in a cell proliferation assay using crystal violet staining. 5-FU/LV was administered 2–3 days before TNF and CP, followed 1 h later by HTX. These cell lines were relatively resistant to HTX alone (42°C for 2 h), but were heterogeneous in their responses to various doses of the other single agents. This heterogeneity was also evident for combined modalities: the geneity was also evident for combined modalities: the HCT-15 cell line exhibited significant supra-additivity for selected doses of CP, TNF and 5-FU/LV, which was further enhanced by hyperthermia. In contrast, the HT-29 cell line did not demonstrate a strong pattern for supra-additivity, whereas the DLD-1 cell line had an intermediate response. Thus, our results suggest one approach to develop effective and dose-sparing multimodality therapeutic regimens for colon adenocarcinoma.  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