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   771篇
  免费   63篇
  国内免费   1篇
耳鼻咽喉   8篇
儿科学   43篇
妇产科学   45篇
基础医学   120篇
口腔科学   60篇
临床医学   94篇
内科学   179篇
皮肤病学   11篇
神经病学   50篇
特种医学   16篇
外科学   94篇
综合类   8篇
预防医学   31篇
眼科学   10篇
药学   37篇
肿瘤学   29篇
  2023年   11篇
  2022年   20篇
  2021年   32篇
  2020年   18篇
  2019年   41篇
  2018年   27篇
  2017年   25篇
  2016年   38篇
  2015年   27篇
  2014年   25篇
  2013年   39篇
  2012年   50篇
  2011年   30篇
  2010年   17篇
  2009年   26篇
  2008年   38篇
  2007年   46篇
  2006年   41篇
  2005年   37篇
  2004年   24篇
  2003年   23篇
  2002年   21篇
  2001年   17篇
  2000年   7篇
  1999年   20篇
  1998年   8篇
  1996年   4篇
  1994年   3篇
  1993年   3篇
  1992年   12篇
  1991年   13篇
  1990年   11篇
  1989年   5篇
  1987年   6篇
  1986年   4篇
  1985年   3篇
  1984年   7篇
  1983年   3篇
  1980年   3篇
  1978年   4篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1974年   3篇
  1973年   8篇
  1972年   3篇
  1971年   7篇
  1970年   4篇
  1969年   3篇
  1968年   2篇
排序方式: 共有835条查询结果,搜索用时 40 毫秒
11.
Gynaecomastia in adolescents is a benign glandular proliferation of the male breast. Secondary causes of gynaecomastia in adolescents are relatively rare and may result from a wide variety of rare pathological conditions. Among these, klinefelter syndrome, complete androgen resistance, adrenal tumours and oestrogen-secreting testicular tumours, hypogonadism, hyperthyroidism, kidney disease and medications play a role in aetiology. The aim of our study is to review the demographic characteristics, hormone profile, aetiological characteristics of paediatric gynaecomastia patients admitted to a single center and to determine the frequency of pathological gynaecomastia. Forty-three male patients with gynaecomastia who applied to the paediatric endocrinology outpatient clinic were included in our study. Demographic characteristics, physical examination findings, hormone profile, breast ultrasonography and karyotype results of the patients were recorded. There were 43 male patients in our study. Thirty-six (83.7%) of the patients were pubertal gynaecomastia, 7 (16.2%) were pathological gynaecomastia. Three of the patients with pathological gynaecomastia were prepubertal gynaecomastia, 2 had klinefelter syndrome, 1 had hypergonadotropic hypogonadism after acute lymphoblastic leukaemia treatment and 1 had gynaecomastia after spirololactone use. Careful evaluation of patients with gynaecomastia is especially important in detecting pathological types. We reported the rare prepubertal gynaecomastia and klinefelter frequency in our study.  相似文献   
12.
We examined a major organ function during 3 h biventricular assisted circulation after acute myocardial infarction model in the pig. In left ventricular circulation, the outflow cannula was placed in the ascending aorta and an inflow cannula through the mitral valve in the left ventricle. A pump (pulsatile group, Zeon Medical, Inc., Tokyo, Japan and nonpulsatile group, Nikkiso HPM-15, Nikkiso, Inc., Tokyo, Japan) was connected to each cannula. In right ventricular circulation, the outflow cannula was placed in the pulmonary artery and an inflow cannula in the right ventricle. The right ventricular circulation was supported by a nonpulsatile pump (Nikkiso HPM-15). The items measured were the regional blood flows of the cortex and medulla in the kidney, white matter and gray mater in brain, and liver; renal arterial flow; carotid arterial flow; portal vein flow; common hepatic arterial flow; arterial ketone body ratio (AKBR); and lactate/pyrubic acid (L/P). In the pulsatile group, the renal cortical blood flow increased, and the medulla blood flow decreased. On the other hand, in the nonpulsatile group, both regional blood flows decreased. That means that in the pulsatile assisted group intrarenal redistribution improved rather than in the nonpulsatile assisted group. In addition the liver regional blood flow, AKBR, and L/P showed significant differences between the pulsatile and nonpulsatile groups. On the other hand, the white matter and gray matter regional blood flows and carotid arterial flow did not show significant differences between the groups. The results of our study indicated that pulsatile circulation produced superior circulation in the kidney and liver, and microcirculation on the cell level was superior as well in early treatment of acute heart failure.  相似文献   
13.
Three copper(ii) tetraaza complexes [Cu(ii)LBr]Br (1a), [Cu(ii)L(CIO4)](CIO4) (2a) and [Cu(ii)L](CIO4)2 (2b), where L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-diene were prepared and confirmed by FTIR, 1HNMR and 13CNMR. The binding interaction of complex (1a, 2a, 2b) with calf thymus DNA (CT-DNA) was investigated using UV-vis absorption, luminescence titrations, viscosity measurements and molecular docking. The findings suggested that complex 1a, 2a and 2b bind to DNA by electrostatic interaction, and the strengths of the interaction were arranged according to 2b > 1a > 2a. The differences in binding strengths were certainly caused by the complexes'' dissimilar charges and counter anions. Complex 2b, with the biggest binding strength towards the DNA, was further applied in developing the porcine sensor. The developed sensor exhibits a broad linear dynamic range, low detection limit, good selectivity, and reproducibility. Analysis of real samples showed that the biosensor had excellent selectivity towards the pork meat compared to chicken and beef meat.

The electrochemical biosensor of porcine using copper(ii) tetraaza complex gave excellent performance with a broad dynamic range, low detection limit, good selectivity and reproducibility. The biosensor could sensitively detect pork DNA in real meat samples.  相似文献   
14.
15.
16.
17.
We tried to isolate rotaviruses from travelers with diarrhea arriving at Nagoya International Airport. 1. Ten cases revealed positive for rotavirus out of 334 diarrheal patients tested during a period from 1985 to 1988. 2. Most of the rotavirus positive cases were in their forties or in their fifties. 3. Geographic distribution of the infected area of the cases was not concentrated with specific countries. 4. Diarrhea was the most frequent clinical manifestations of the cases. 5. There was no cluster in seasonal distribution of the cases.  相似文献   
18.
19.

Purpose

In this study, we aimed to establish a quantitative threshold value in the diagnosis of subacromial impingement syndrome by measuring the thickness of the subacromial bursa during abduction and adduction.

Materials and methods

Forty-five patients with subacromial impingement syndrome and 54 healthy individuals underwent dynamic shoulder ultrasonography. The subacromial bursa, between the supraspinatus tendon margin and peribursal adipose tissue, was measured between the acromion and humeral head at its widest part. The subacromial impingement ratio was calculated by dividing the subacromial bursa thickness during abduction to the subacromial bursa thickness during adduction. Shapiro–Wilk test was used in the assessment of normal distribution of parameters.

Results

The mean subacromial bursa thickness in the abduction position was 1.8 ± 1.1 mm in the study group and 0.9 ± 0.3 mm in the control group. The mean subacromial bursa thickness in the adduction position was 0.9 ± 0.5 mm in the study group and 0.8 ± 0.3 mm in the control group. The subacromial impingement ratio showed a statistically significant difference between groups (p < 0.0001), and the ratio being 2.0 ± 0.5 in the study group and 1.2 ± 0.1 in the control group. For measurements performed in the abduction position, the best cut-off value was calculated as 1.3 mm, and sensitivity and specificity were 70.6 and 85.2%, respectively. The best cut-off value was 1.4 for the subacromial impingement ratio, and sensitivity and specificity were 88.2 and 96.3%, respectively.

Conclusion

Subacromial impingement ratio is a very practical and reliable method in subacromial impingement syndrome diagnosis.
  相似文献   
20.
Epitope mapping of hTSH was carried out using 19 monoclonal antibodies prepared with hTSH or its beta-subunit as antigen. The affinity constants of the monoclonal antibodies ranged from 9.6 X 10(7) to 5.7 X 10(9) mol/l for hTSH. The binding activities of monoclonal antibodies were maintained or in some cases rather enhanced after removal of the sugar moiety of the subunits of hTSH, and completely diminished after reduction of intramolecular S-S bonds in the subunits of hTSH. Ten monoclonal antibodies recognized the epitopes on hTSH (alpha:beta subunit combined form) and on free alpha-subunit form. Eight other antibodies recognized the epitopes on free/or combined form of beta-subunit, all of which did not recognize any other human glycoprotein hormones. The monoclonal antibodies directed against the alpha-subunit could bind also other human glycoprotein hormones to a varying extent. On the basis of results from competitive binding studies, the antibodies directed against alpha-subunit and those against beta-subunit were each classified into five subgroups recognizing different antigenic determinants. The remaining one antibody recognized an epitope expressed only by hTSH and not by the free subunits. In addition, a positive cooperativity on the binding of hTSH was observed between monoclonal antibodies directed towards a particular epitope on the alpha-subunit and those towards a epitope on the beta-subunit. From these data, two-dimensional map of epitopes on hTSH was constructed. The epitopes on each subunit were found to form a cluster with complicated overlapping, suggesting a highly conformational structure.  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