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   399篇
  免费   5篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   5篇
妇产科学   2篇
基础医学   36篇
口腔科学   5篇
临床医学   28篇
内科学   76篇
神经病学   18篇
特种医学   11篇
外科学   111篇
综合类   3篇
预防医学   15篇
药学   15篇
肿瘤学   76篇
  2023年   3篇
  2022年   1篇
  2021年   5篇
  2020年   7篇
  2019年   7篇
  2018年   10篇
  2017年   9篇
  2016年   8篇
  2015年   2篇
  2014年   6篇
  2013年   18篇
  2012年   12篇
  2011年   19篇
  2010年   11篇
  2009年   10篇
  2008年   27篇
  2007年   16篇
  2006年   27篇
  2005年   35篇
  2004年   17篇
  2003年   21篇
  2002年   25篇
  2001年   4篇
  2000年   2篇
  1999年   7篇
  1998年   7篇
  1997年   7篇
  1996年   9篇
  1995年   3篇
  1994年   7篇
  1993年   10篇
  1992年   6篇
  1991年   6篇
  1990年   3篇
  1989年   4篇
  1988年   3篇
  1987年   3篇
  1986年   2篇
  1985年   3篇
  1984年   7篇
  1983年   3篇
  1982年   2篇
  1981年   3篇
  1979年   2篇
  1978年   3篇
  1977年   1篇
  1973年   1篇
  1969年   1篇
  1966年   1篇
排序方式: 共有406条查询结果,搜索用时 15 毫秒
401.
402.
BACKGROUND: To describe the clinical characteristics of patients with stable angina pectoris who develop heart failure and the events preceding its onset. METHODS AND RESULTS: Of 7665 patients with stable angina in the ACTION trial, which compared long-acting nifedipine to placebo, 207 (2.7%) developed heart failure (HF) during a mean follow-up of 4.9 years. Those who developed HF were significantly (P<0.05) older, more often had diabetes, had a more extensive history of cardiovascular disease, lower ejection fractions, a higher serum creatinine and glucose, a lower haemoglobin, and were more often on blood pressure lowering drugs. A cardiac event or an intervention (n=155), a significant non-cardiac infection (n=19) or poor control of hypertension (n=12) preceded the development of HF in 186/207 cases (90%). There was no obvious precipitating factor in the remaining 21 patients (10%). Myocardial infarction increased the risk of the development of new HF within one week more than 100-fold. Nifedipine reduced the incidence of HF by 29% (P=0.015). CONCLUSIONS: The development of heart failure is uncommon in patients with stable angina, and even less so in the absence of an obvious precipitating factor.  相似文献   
403.
404.
BACKGROUND: The aim of this study was to investigate how the expression of genes regulating angiogenesis is altered when prostate cancer cells progress into androgen-independency. METHODS: A gene array specific for angiogenesis was used to compare the human prostate cancer cell line LNCaP (androgen-dependent) with its more angiogenic and tumorigenic subline LNCaP-19 (androgen-independent). Results were verified with real-time RT-PCR, and further investigations were focused on the angiogenesis inhibitor a disintegrin and metalloproteinase with thrombospondin motifs 1 (ADAMTS1). Expression of ADAMTS1 was investigated in vitro as well as in subcutaneous tumors with real-time RT-PCR and Western blotting. Microvessel density (MVD), versican proteolysis and protein levels of TIMP-2 and TIMP-3, known as ADAMTS1 inhibitors, were also analyzed in tumor xenografts. RESULTS: The gene array revealed decreased expression of ADAMTS1, ephrin-A5, fibronectin 1, and neuropilin 1 in LNCaP-19 compared to LNCaP, while expression of midkine and VEGF were increased. Further studies showed that mRNA and protein levels of ADAMTS1 were significantly lower in LNCaP-19 compared to LNCaP, both in vitro and in subcutaneous tumors. The amount of ADAMTS1 correlated negatively with MVD, but no relation was found between ADAMTS1 and versican proteolysis. CONCLUSIONS: Expression of several genes associated with angiogenesis was altered during transition into androgen-independency. Among these, a significant decrease was found for ADAMTS1, whose expression inversely correlated with MVD. Its role in progression of prostate cancer needs further investigation, but this inhibitor of angiogenesis could be an interesting candidate for future anti-angiogenic therapy.  相似文献   
405.
Unilateral cryptorchism was induced in adult rats for 24 h, and its effect on testicular morphology and intratesticular testosterone concentration after hCG-stimulation were studied. In seminiferous, tubules from abdominal testes an increased number of degenerating germ cells was noted in stages XIV-III of the spermatogenic cycle and Sertoli cells contained an increased amount of lipid droplets in stages XIV-VIII. However, germ cells and Sertoli cells from tubules at other stages of the cycle appeared unaffected. In scrotal testes the size of peritubular Leydig cells varied in phase with the spermatogenic cycle. The largest cells were found adjacent to stage VII-VIII and the smallest adjacent to stage XI-XII. In abdominal testes no stage-dependent variation in the size of peritubular Leydig cells was seen. Perivascular Leydig cells were of equal size in abdominal and scrotal testes. The testicular testosterone concentration following stimulation with a low dose of hCG was significantly lower in abdominal testes. It is suggested that the seminiferous tubules locally modulate Leydig cell function and that the stage specific stimulatory influence from stage VII-VIII is rapidly lost during experimental cryptorchidism.  相似文献   
406.
Objective: To examine general sleep habits and sleep disturbances among patients with treated Wilson's disease (WD), and in comparison with an age- and sex-matched reference group (RG). Methods: Twenty-four patients with WD with a mean ( &#45 s ) age of 35.1 &#45 8.7 years and a disease duration of 17.7 &#45 5.1 years were investigated using a standardized sleep questionnaire comprising 87 questions concerning sleep habits, sleeping difficulties, demographic and lifestyle variables. The results were compared with those from a random sample of 72 individuals. Results: There was no significant difference in sleep time during the night, but WD patients had a significantly greater number of nocturnal awakenings compared with the RG. Fifty-nine per cent of the WD patients reported frequently being awake for more than 30 min during the night. Number of nocturnal awakenings was correlated to nightmares and palpitations only in the WD group. WD patients complained significantly more often than the RG over not feeling rested after sleep, taking frequent naps and fatigue during the daytime. Moreover, sleep paralysis and cataplexy occurred more often in the WD patients than in the RG. Conclusion: The sleep pattern of patients with treated WD differed from that of the reference group. The spectrum of reported symptoms by patients with treated WD suggests an altered REM sleep function. Future studies with objective methods are required to elucidate the mechanisms involved.  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