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   401篇
  免费   29篇
  国内免费   5篇
耳鼻咽喉   2篇
儿科学   25篇
妇产科学   3篇
基础医学   34篇
口腔科学   30篇
临床医学   46篇
内科学   76篇
皮肤病学   5篇
神经病学   21篇
特种医学   62篇
外科学   35篇
综合类   28篇
预防医学   17篇
眼科学   10篇
药学   10篇
中国医学   4篇
肿瘤学   27篇
  2023年   1篇
  2022年   2篇
  2021年   10篇
  2020年   3篇
  2019年   3篇
  2018年   5篇
  2017年   7篇
  2016年   6篇
  2015年   10篇
  2014年   9篇
  2013年   21篇
  2012年   21篇
  2011年   14篇
  2010年   27篇
  2009年   12篇
  2008年   14篇
  2007年   7篇
  2006年   16篇
  2005年   9篇
  2004年   8篇
  2003年   5篇
  2002年   4篇
  2001年   3篇
  2000年   6篇
  1999年   8篇
  1998年   23篇
  1997年   14篇
  1996年   19篇
  1995年   8篇
  1994年   13篇
  1993年   10篇
  1992年   6篇
  1991年   9篇
  1990年   5篇
  1989年   12篇
  1988年   12篇
  1987年   15篇
  1986年   12篇
  1985年   6篇
  1984年   6篇
  1983年   3篇
  1982年   8篇
  1981年   2篇
  1980年   5篇
  1979年   1篇
  1978年   1篇
  1977年   3篇
  1976年   7篇
  1975年   2篇
  1971年   2篇
排序方式: 共有435条查询结果,搜索用时 31 毫秒
21.
The more metastatic sites and bone marrow metastasis in small cell lung cancer (SCLC), the worse the prognosis. Diagnosing the bone marrow invasion at the beginning of the therapy is important for determining of the prognosis and planning the treatment. Abnormalities of some blood parameters may help to estimate the extent of bone marrow invasion by cancer cells. In this retrospective review, the changes in routine laboratory tests that may indicate bone marrow invasion, the predictive values of these tests, and the prognostic importance of bone marrow invasion were evaluated in SCLC patients who were being followed up according to a protocol. One hundred and forty‐four patients with SCLC were enrolled in this study. Retrospectively, it was evaluated that 25 (17.4%) of the patients had bone marrow metastasis. According to univariate analysis, there was a significant difference between hemoglobin, white blood cell count, platelet count, lactate dehydrogenase, alkaline phosphatase and uric acid of the patients with and without bone marrow involvement. Among the biochemical parameters, the elevated LDH and AP had the highest sensitivity and specificity as indicators of bone marrow invasion (0.80–0.82 and 0.84–0.78, respectively). The median overall survival of extensive‐stage disease with and without bone marrow metastasis were 4.0 ± 1.0 months (95% CI 2.2–5.7) and 7.0 ± 1.2 months (95% CI 4.7–9.3), respectively (P = 0.03). Bone marrow metastasis was found to be an indicator of a bad prognosis. Bone marrow biopsy, that is an invasive procedure, can be performed on selected patients who have changes of routine laboratory tests suggesting bone marrow invasion.  相似文献   
22.
Molecular analysis of PKU in Ireland   总被引:1,自引:0,他引:1  
Classical phenylketonuria (PKU: McKusick No. 261600) is caused by mutations occurring at the phenylalanine hydroxylase (PAH) locus on chromosome 12 and has a prevalence in Ireland of 1 in 4500. We examined 304 independent alleles from 350 patients for the presence of six mutations and have characterized VNTR alleles within the minisatellite region 3' to the PAH gene in patients carrying the most prevalent mutation. R408W was the most common mutation found, with a relative frequency of 42%. All other mutations had relative frequencies of <10%. VNTR analysis showed that the R408W mutation is associated with the VNTR-8 allele in the Irish population, indicating that R408W is associated with RFLP haplotype 1. This differs from that reported from eastern Europe where R408W is associated with RFLP haplotype 2/VNTR-3; an observation which has led several groups to propose a Balto-Slavic origin for this mutation. These results support the hypothesis of a second, independent founding event for the R408W mutation on an RFLP haplotype 1 VNTR-8 chromsome background in the Irish/Celtic population.  相似文献   
23.
24.
25.
Electrochemotherapy associates the local delivery of anticancer drugs with the administration of permeabilizing electric pulses that support the antiblastic action. The basic instrumentation for this therapy is constituted by a pulse generator and various specific electrodes. While many efforts have been profuse by researchers in this field to obtain the standardization of the pulse generating equipment over the past 15 years, the delivery apparatus still needs refinements in order to reach most of the body districts, to control the homogeneity and stability of the electric fields and to further reduce morbidity. With the aim to develop innovative electrodes able to satisfy, at least partially, these requirements, extensive studies on pet patients with spontaneous neoplasms have been conducted, leading to the manufacturing of several different prototypes. In this paper we discuss the rationale of 11 different electrodes, briefly summarize the results obtained and their experimental validation, also presenting five paradigmatic clinical cases. In particular, it is shown that the caliper electrodes are more suited for the treatment of cutaneous and subcutaneous lesions, while the needle arrays are more efficacious in intraoperative settings. Furthermore, relevant peculiarities of unipolar electrodes are examined with a particular focus on the irregular current paths that they produce and on the potentialities of this feature. Remarkably, the decrease of the steric encumbrance turned out to be a stronger factor in electrode design than the containment of the total number of electric fields covered in serial ECT sessions. In the conclusions, perspectives and new challenges of electrode design for electrochemotherapy are illustrated.  相似文献   
26.
Abstract – The occurrence of supra- and subgingival calculus, gingival inflammation, periodontal pockets ( 5 mm) and alveolar bone loss was determined in children (10-19 yr) with Down's syndrome (D-S) and in an aged- and sex-matched control group ( n = 39). Of D-S children ( n = 71), 39 of the patients (mean age 15.5 yr) cooperated in a clinical and roentgenologic examination. Alveolar bone loss was determined around incisors and first molars on intraoral radiographs when the distance between cementoenamel junction (GEJ) to alveolar crest (AC) exceeded 2.0 mm. Alveolar bone loss was diagnosed in 39% of the D-S children compared to 3% in the control group ( P <0.001). Of the total number of sites examined on radiographs the distance from CEJ to AC exceeded 2.0 mm in 8% in the D-S group compared to 0.2% in the control group ( P <0.001). The frequency of sites with alveolar bone loss in D-S children was significantly ( P <0.001) higher around the mandibular incisors compared to first molars. The study shows that early signs of periodontitis are frequently seen in D-S children as early as 11 yr of age and the lesions are first diagnosed in the mandibular anterior region.  相似文献   
27.
Color Doppler flow imaging or compression ultrasound (US) was used to prospectively determine frequency of thrombosis at 54 venous insertion sites (47 in common femoral veins, seven in right internal jugular veins) after percutaneous placement of Greenfield filters for interruption of the inferior vena cava. Fifty-one filters were successfully placed in 51 patients with a dilator set or a balloon angioplasty catheter. Nine focal thrombi were detected in the common femoral vein (19%) and one in the right internal jugular vein (14%). Use of dilators induced eight thrombi (24%), compared with two (10%) from balloon catheters. The left common femoral vein had a high frequency of thrombosis, regardless of dilation technique (five of nine). Of nine patients with acute common femoral vein thrombosis, four became symptomatic within 10 days after the procedure. Patients may remain asymptomatic or have delayed symptoms; thus, US is valuable for determining patients at risk of thrombosis of the common femoral vein.  相似文献   
28.
Myocardial tagging in polar coordinates with use of striped tags   总被引:1,自引:0,他引:1  
Bolster  BD  Jr; McVeigh  ER; Zerhouni  EA 《Radiology》1990,177(3):769-772
Regional deformation abnormalities in the heart wall provide a good indicator of ischemia. Myocardial tagging with magnetic resonance imaging is a new method of assessing heart wall motion during contraction. Current methods of myocardial tagging either do not provide two-dimensional information or lack a coordinate system well adapted to the morphology of the heart. In this article, the authors describe a new tagging method that provides a true polar coordinate system, with both radial and angular dimensions. This is accomplished with use of a section-selective version of spatially modulated magnetization resulting in striped tags (STAGs). These STAG planes are placed in the myocardium in a star pattern so that they intersect on the long axis of the heart and stripes appear through the width of the heart wall. In the short-axis view during contraction, rotation around the long axis yields angular information such as shear and twist, while separation of the stripes within the myocardium permits measurement of radial thickening. Therefore, this method provides a coordinate system for calculating two-dimensional strain that is adapted to the morphology of the left ventricle.  相似文献   
29.
In order to quantify presence of residual BCC in patients with histologic positive margins after the first excison and to correlate the presence of residual tumor in re‐excised lesions with the location of the positive margin on the first excision, a retrospective evaluation of 2053 surgically treated BCC was performed. Only 38.3% of the re‐excised lesions showed residual tumor. In the group of re‐excised lesions where residual BCC was found, 13% had lateral positive margin in the first excision, 39% had deep positive margin and 48% had both lateral and deep positive margins. In the group of re‐excised lesions where no residual BCC was found, 49% of the primary excised lesions had lateral positive margin, 32% had deep positive margin and 19% had both deep and lateral positive margins. The association between residual tumor and positive margins was statistically significant (p = 0.01). Our findings confirm that presence of residual tumour is more likely when both lateral and deep margins are compromised.  相似文献   
30.
Abstract – Oral health was studied in a group of asthmatic children (n = 61). The children were divided in two groups, 5–10 and 11–18 yr of age. The individuals with asthma were further sub grouped with respect to the disease severity. Severe asthma was defined as more than 10 asthmatic attacks per year. This patient group had daily medication compared to children with moderate asthma (<10 asthmatic attacks/yr) who medicated temporarily. 55 age matched children from the same area made up the control group. Ail children were examined clinically and two bitewing radiographs were taken. The results showed no statistically significant differences concerning caries prevalence and gingival condition in asthmatic children compared to a healthy control group. The study shows that neither the asthma per se nor the disease severity affected the caries prevalence and gingival condition in asthmatic children.  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