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   547篇
  免费   15篇
  国内免费   15篇
儿科学   37篇
妇产科学   4篇
基础医学   42篇
口腔科学   7篇
临床医学   46篇
内科学   128篇
皮肤病学   4篇
神经病学   5篇
特种医学   133篇
外科学   40篇
综合类   44篇
预防医学   14篇
眼科学   5篇
药学   41篇
肿瘤学   27篇
  2023年   1篇
  2021年   2篇
  2020年   2篇
  2019年   2篇
  2018年   5篇
  2017年   3篇
  2016年   3篇
  2015年   7篇
  2014年   9篇
  2013年   20篇
  2012年   10篇
  2011年   9篇
  2010年   10篇
  2009年   20篇
  2008年   9篇
  2007年   15篇
  2006年   15篇
  2005年   22篇
  2004年   13篇
  2003年   11篇
  2002年   9篇
  2001年   8篇
  2000年   10篇
  1999年   16篇
  1998年   23篇
  1997年   39篇
  1996年   46篇
  1995年   25篇
  1994年   25篇
  1993年   25篇
  1992年   6篇
  1991年   5篇
  1990年   6篇
  1989年   17篇
  1988年   18篇
  1987年   14篇
  1986年   21篇
  1985年   7篇
  1984年   5篇
  1983年   6篇
  1982年   11篇
  1981年   5篇
  1980年   8篇
  1979年   2篇
  1978年   8篇
  1977年   6篇
  1976年   11篇
  1975年   6篇
  1971年   1篇
排序方式: 共有577条查询结果,搜索用时 15 毫秒
31.
Background Patients with prostate cancer with a pre-operative prostate-specific antigen (PSA) τ;15ng/ml who undergo radical retropubic prostatectomy (RRP) generally do not have a good outcome, yet may have organ-confined cancer and should be offered the option of surgery. Aim To assess the outcome of patients who underwent RRP with a pre-operative PSA ≥ 15ng/ml. Methods Thirty-four patients, mean pre-operative PSA: 25.46ng/ml (15.03–76.6) and mean Gleason score: 6.4 (5–9) were assessed. Results Two groups were identified. Group I: 41% (14/34) have no biochemical recurrence to mean follow up of 58 months (30–106). Mean PSA: 18.8ng/ml (15.03–25.84). Mean Gleason score: 6.1 (5–7). Clinical stage: T1c in 80%. No patient had seminal vesicle or lymph node involvement. Group II: 59% (20/34) have biochemical recurrence or died (3) from their disease to mean follow up of 66 months (36–98). Mean PSA: 28.9ng/ml (15.28–76.6). Mean Gleason score: 6.7 (5–9). Clinical stage: T1c in 25%. Eleven patients had seminal vesicle (8) involvement or positive lymph nodes (3) or both (2). Conclusion RRP seems feasible in patients whose pre-operative PSA is between 15 and 25ng/ml with stage T1c, Gleason score ≤ 7 and negative lymph node frozen section.  相似文献   
32.
Clara cell secretory protein (CC16) is a 16kDa protein secreted by Clara cells in the lining fluid of bronchiolar and bronchial epithelium. CC16 presents several biologic properties, and has been shown to have immunomodulatory and anti-inflammatory activity. It may play a role in controlling inflammation in the airway. There is some evidence that the CC16 level is primarily lower in adult individuals with bronchial asthma, thus contributing to its pathophysiology. This study was designed to examine CC16 serum levels of children, healthy and with asthma. An enzyme solid phase immunoassay utilizing monoclonal antibody to CC16 was the analytical method to determine the protein concentration in blood sera. The method showed excellent linearity, high sensitivity (detection limit: <50 ng/l) and precision. It was found that asthmatic children appear significantly lower levels (P < 0.001) of CC16 in serum as compared to healthy ones. It is, therefore, concluded that CC16 may be a useful diagnostic index of bronchial asthma in the early child-age.  相似文献   
33.
THP-1 is a monocytic cell line originally derived from a patient with acute monocytic leukemia. Interactions of THP-1 cells with other cells and their microenvironment are largely determined by proteoglycans (PGs), the identity of which has not been determined. Previous studies on glycosaminoglycan expression by THP-1 cells and peripheral blood mononuclear cells from healthy individuals showed that both cell types secrete mainly chondroitin sulfate PGs to the culture medium, whereas heparan sulfate PGs are mainly retarded at the cell membrane. However, limited data on the type of PGs synthesized by THP-1 is available. In this study, the identification of PG types synthesised by THP-1 cells, which are not differentiated to macrophages, was examined. Analysis at the mRNA level by RT-PCR showed the expression of six cell membrane-associated PGs: syndecan-1, -2 and -4, glypican-1, thrombomodulin and CD44. Cell extraction, ion-exchange chromatography and dot blot analysis of the isolated PG populations with monoclonal antibodies showed the presence of syndecan-1 and thrombomodulin; the other two syndecans were not detected in any of the isolated populations. The synthesis of matrix PGs was also studied. THP-1 monocytes were positive for the mRNA encoding for versican and perlecan, but not for those encoding for decorin, biglycan, betaglycan and fibromodulin. The mRNA encoding for two versican splice variants V0 (351 bp) and V1 (386 bp), but not for V2, were identified. Biochemical analysis showed the presence of perlecan and of two populations of versican in culture medium with protein cores of average molecular sizes similar to those of V0 and V1. The production of these large matrix PGs by THP-1 monocytes is reported for the first time and may be of importance in monocyte malignant transformation and differentiation.  相似文献   
34.
BACKGROUND: Little is known about the variation of the glycemic index (GI) in the diet of European outpatients with type 1 diabetes and how the GI of a commonly consumed diet is associated with metabolic control. OBJECTIVE: The present study examined the calculated dietary GI of European outpatients with type 1 diabetes for possible relations to glycated hemoglobin (Hb A(1c)) and serum lipid concentrations. DESIGN: The relation of the GI (calculated from a 3-d dietary record) to Hb A(1c), serum cholesterol (total, LDL, and HDL), and fasting triacylglycerol was analyzed in 2810 people with type 1 diabetes from the EURODIAB Complications Study. RESULTS: The GI was independently related to Hb A(1c) (P = 0.0001). Compared with the highest GI quartile (median GI: 89), adjusted Hb A(1c) in the lowest GI quartile (median GI: 75) was 11% lower in patients from southern European centers and 6% lower in patients from northern, western, and eastern European centers. Of the serum lipids, only the HDL cholesterol in patients from these European centers was independently related to the GI (P = 0.002). In southern European centers, the consumption of pasta, temperate-climate fruit, white bread, and potatoes largely determined the patients' dietary GI, whereas in the northern, western, and eastern European centers, consumption of bread, potatoes, and temperate-climate fruit was most relevant. CONCLUSIONS: This study in European patients with type 1 diabetes showed that a lower dietary GI is related to lower Hb A(1c) concentrations, independently of fiber intake. The consumption of bread and pasta had the biggest effect on the overall dietary GI of European outpatients.  相似文献   
35.
PURPOSE: The influence of the nonionic contrast agent iohexol on blood pH and the cation electrolytes Ca, Na, K and Mg was studied in vivo in humans during the intravenous pyelography. MATERIAL AND METHODS: A population of 28 patients without renal function impairment or electrolyte imbalance was divided into two equal groups. The first group received an intravenous injection of 0.6 mL Omnipaque per kg of body weight (0.388g iohexol/kg and 0.18 g iodine/kg). The second group received a double dose of Omnipaque (1.2 mL iohexol/kg; 0.776g iohexol/kg and 0.36g iodine/kg). Blood samples (5 mL) were taken before the injection of the contrast medium and 5, 10 and 20 minutes (marking the end of the examination) after the injection. Blood pH was also determined immediately after each sample collection, while electrolytes were measured in the laboratory. Systolic and diastolic blood pressure were also determined simultaneously with each sample collection using a mercury manometer. RESULTS: Iohexol in simple and double doses did not have any statistically significant effect either on blood pH or on blood serum electrolytes during intravenous pyelography. Blood pressure, both systolic and diastolic, remained stable in all the patients during the examination. CONCLUSIONS: Our results show that the nonionic contrast medium iohexol at the doses used in routine intravenous pyelography does not have any influence on blood pH and serum cardioactive cation electrolytes in humans. An electrolyte imbalance is always a risk factor that may contribute to the development of cardiovascular side effects. This factor is eliminated when iohexol is administered intravenously instead of an ionic agent.  相似文献   
36.
Human polyvalent intravenous immunoglobulin (IVIG) preparations are used as a complementary aid to the proper antimicrobial treatment of severely septic patients in intensive care units (ICUs) and/or as a prophylactic agent to immunocompromized hosts, particularly prone to bacterial infections. There is skepticism about the usefulness of IVIGs since it is not known whether their administration ensures the enhancement of humoral immune responses by providing a sufficient amount of specific antibodies towards the specified bacterial pathogen to be treated. In this report, a simple and reproducible enzyme-linked immunosorbent assay for determining the content of specific antibodies against bacterial surface antigens in commercially available IVIG preparations is described. The method is also easily applied to determine the amount of bacterial antibodies in blood serum. The levels of specific antibodies toward Gram positive and negative pathogenic isolates often encountered in ICUs were estimated in two IVIG (Sandoglobulin® and Gamimmune®) preparations. Significant differences regarding the content of antibodies to certain clinically bacterial isolates were identified not only between the two IVIG preparations tested, but also among various lots from each IVIG preparation. No significant variation (P≤0.001) among the bottles derived from the same lot was determined in both preparations. The variation in the levels of specific antibodies in IVIG preparations may be attributed to differences between the donor pools as well as the manufacturing procedure. Application of the method to patients with primary immune deficiencies showed that infusion of highly reactive IVIG preparations enhanced significantly their humoral response toward various pathogens. The results of this study suggest that the content determination of pathogen-specific antibodies in IVIG preparations before administration may be of great importance for treating bacterial infections.  相似文献   
37.
This study evaluated the accuracy of the interpretation of the chest film in delineating localised abnormalities of ventilation and perfusion, as well as the overall severity of airways obstruction, exercise tolerance, and clinical condition in children with cystic fibrosis. Radiographic findings in various regions of the chest film were compared with the functional values obtained with regional lung function tests which evaluated the arrival and disappearance of boluses of radioactive nitrogen given by inhalation and infusion. While the more severely affected areas on the chest radiograph were found to correlate with similar regions on the lung function tests, as did overall scores, errors occurred in some cases if the x-ray film alone was used as a judge of regional physiological derangement. In addition the degree of airways obstruction, the exercise tolerance on a cycle ergometer, and clinical grading, each correlated significantly with the radiographic score. We conclude that the chest radiograph is a good indicator of the overall severity of the lung disease and that it correlates well with exercise tolerance and clinical condition in cystic fibrosis.  相似文献   
38.
Hafenrichter  DG; Wu  X; Rettinger  SD; Kennedy  SC; Flye  MW; Ponder  KP 《Blood》1994,84(10):3394-3404
Hepatic gene therapy could be used to treat a number of inherited blood diseases such as hemophilia or thrombophilia. Although liver-directed retroviral transduction can result in long-term gene expression in vivo, the low level of protein production has limited its clinical application. We reasoned that the insertion of liver-specific promoters into retroviral vectors would increase gene expression in vivo. The 347- bp human alpha 1-antitrypsin (hAAT), the 810-bp murine albumin (mAIb), the 490-bp rat phosphoenolpyruvate carboxykinase (rPECK), and the 596- bp rat liver fatty acid binding protein promoters were inserted into a Moloney murine leukemia retroviral backbone containing the hAAT reporter gene. Vectors that produced appropriately sized RNA and hAAT protein in vitro were tested in vivo by transducing regenerating rat livers. Long-term serum expression of the hAAT reporter gene was normalized to retroviral transduction efficiency as determined by using a polymerase chain reaction-based assay of genomic DNA from transduced rat livers. The hAAT, mAIb, and rPEPCK promoters were, respectively, 35- , 8-, and 0.02-fold as strong as the previously studied constitutive Pol-II promoter. We conclude that the hAAT promoter resulted in the highest expression from a retroviral vector and may result in therapeutically significant expression of other clinically significant blood proteins.  相似文献   
39.
Low-artifact intravascular devices: MR imaging evaluation   总被引:2,自引:0,他引:2  
Flow-phantom magnetic resonance (MR) imaging, with use of both spin-echo (SE) and gradient-echo (GRE) techniques at 1.5 T, was performed on the percutaneous Greenfield (beta-III titanium alloy [TMA wire]), Amplatz (MP32-N alloy), and Simon nitinol filters and TMA wire facsimiles of the bird's nest, Gunther, new retrievable, and Amplatz vena caval filters. SE imaging allowed detection of thrombi as small as 5 X 5 mm trapped within the percutaneous Greenfield, Simon nitinol, and TMA-wire facsimile filters; with the MP32-N Amplatz filter, a larger volume of thrombus (10 X 20-mm clots) was necessary for clot detection. GRE imaging allowed detection of intraluminal tilting of the percutaneous Greenfield and facsimile Amplatz (TMA-wire) filters. GRE imaging was useful for demonstrating postfilter turbulence due to clots, which was greatest for the Amplatz filter. Imaging of facsimile vascular devices made of tantalum or TMA wire did not cause the severe "black-hole" MR artifacts typical of the stainless-steel devices. SE and GRE imaging were very useful for determining caval patency in two patients with previously placed Mobin-Uddin filters. Noninvasive MR evaluation of blood vessels in the presence of a variety of low-artifact intravascular devices appears feasible.  相似文献   
40.
急性有机磷农药中毒120例的救治   总被引:1,自引:0,他引:1  
0 引言 近年来 ,我科在救治急性有机磷农药 (organophos-phorus,OP)中毒方面 ,积累了一些经验 ,现报告如下 .1 对象和方法1 .1 对象 本组 1 2 0例符合《急诊急救学》中的诊断标准 [1 ](男 2 9例 ,女 91例 ) ,年龄 1 .5~ 70岁 ,平均 2 8.6岁 .经口中毒 99例 ,经皮肤中毒 2 1例 .轻度中毒 1 5例 ,中度中毒 42例 ,重度 (含极重度 )中毒 6 3例 . 1 996年 39例 ,1 997年 43例 ,1 998年 38例 . DDV 79例 ,乐果 2 0例 ,混合性中毒 1 0例 ,水胺磷 3例 ,氧化乐果、 391 1、 1 0 5 9、对硫磷各 2例 ,敌百虫 1例 ,药名不详 1 0例 .服毒量 >2 5 …  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