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   6849篇
  免费   306篇
  国内免费   74篇
耳鼻咽喉   111篇
儿科学   124篇
妇产科学   257篇
基础医学   518篇
口腔科学   132篇
临床医学   602篇
内科学   1914篇
皮肤病学   86篇
神经病学   374篇
特种医学   289篇
外科学   1379篇
综合类   26篇
预防医学   309篇
眼科学   146篇
药学   309篇
中国医学   3篇
肿瘤学   650篇
  2024年   3篇
  2023年   47篇
  2022年   132篇
  2021年   239篇
  2020年   130篇
  2019年   195篇
  2018年   207篇
  2017年   146篇
  2016年   164篇
  2015年   166篇
  2014年   298篇
  2013年   333篇
  2012年   589篇
  2011年   605篇
  2010年   364篇
  2009年   332篇
  2008年   571篇
  2007年   582篇
  2006年   481篇
  2005年   405篇
  2004年   351篇
  2003年   314篇
  2002年   259篇
  2001年   34篇
  2000年   13篇
  1999年   31篇
  1998年   52篇
  1997年   26篇
  1996年   30篇
  1995年   23篇
  1994年   18篇
  1993年   11篇
  1992年   10篇
  1991年   5篇
  1990年   11篇
  1989年   3篇
  1988年   5篇
  1987年   4篇
  1986年   4篇
  1984年   3篇
  1983年   3篇
  1982年   11篇
  1981年   4篇
  1980年   2篇
  1976年   2篇
  1975年   1篇
  1974年   4篇
  1973年   2篇
  1972年   1篇
  1969年   1篇
排序方式: 共有7229条查询结果,搜索用时 15 毫秒
21.
The discriminatory effects of categorizing psychiatric patients into competent and incompetent, have urged lawyers, philosophers and health care professionals to seek a functional approach to capacity assessment. Dutch and English law have produced some guidelines concerning this issue. So far, most legal systems under investigation have concentrated on alternatives for informed consent by the patient in case of mental incapacity, notably substitute decision-making, intervention of a judge and advance directives. It is hard to judge the way in which the law may further adapt to a more functional assessment of capacity, because the nature of law shows that legal reforms usually take place only when new methods have been accepted by the field. This is not yet the case today.  相似文献   
22.
23.
The Frank''s sign (FS) is a diagonal earlobe crease running from the tragus to the edge of the auricle. In this case, we describe a 71 years‐old male patient with FS who presented to the emergency department complaining of epigastric pain. A non‐ST elevation myocardial infarction was diagnosed.  相似文献   
24.
Purpose: To examine the association between measures of neuroretinal matrix integrity as determined with Rarebit perimetry and optical coherence tomography (OCT)‐derived retinal nerve fibre layer thickness. Methods: One randomly selected eye of 30 White primary open‐angle glaucoma patients (age: 60.9 ± 11.7 years; MD: ?3.2 ± 5.1 dB) and 16 healthy White individuals (age: 33.2 ± 6.4 years; MD: ?0.8 ± 0.8 dB) were included in the study. Participants underwent Rarebit perimetry testing (central field, software version 4) and an OCT fast retinal nerve fibre layer (RNFL) scan. Correlation was investigated between hemifield Rarebit scores and the corresponding RNFL values, as well as between global Rarebit scores and the respective RNFL measures. Results: Statistically significant correlations of average hit rate (HR) < 90 and mean hit rate (MHR) were detected with Max–Min and average thickness (Pearson’s r ranging from 0.393 to 0.474). Number HR < 90 showed a moderate correlation only with Max–Min (r = ?0.396, P = 0.030). Regarding the association between hemifield hit rates and the corresponding OCT thickness parameters, only inferior maximum correlated moderately with HR superior (r = 0.385, P = 0.035). A tendency was detected for the relationship of superior maximum with HR inferior (r = 0.345, P = 0.062). For the control group, no significant correlation was found for any of the global or hemifield indices and the corresponding thickness values. Conclusion: Although Rarebit perimetry is based on a physiological principle distinctly different from conventional perimetry, it provides global indicators of neuroretinal matrix integrity that correlate with some OCT‐derived RNFL thickness measures.  相似文献   
25.
Fetal stroke is an important cause of cerebral palsy but is difficult to diagnose unless imaging is undertaken in pregnancies at risk because of known maternal or fetal disorders. Fetal ultrasound or magnetic resonance imaging may show haemorrhage or ischaemic lesions including multicystic encephalomalacia and focal porencephaly. Serial imaging has shown the development of malformations including schizencephaly and polymicrogyra after ischaemic and haemorrhagic stroke. Recognised causes of haemorrhagic fetal stroke include alloimmune and autoimmune thrombocytopaenia, maternal and fetal clotting disorders and trauma but these are relatively rare. It is likely that a significant proportion of periventricular and intraventricular haemorrhages are of venous origin. Recent evidence highlights the importance of arterial endothelial dysfunction, rather than thrombocytopaenia, in the intraparenchymal haemorrhage of alloimmune thrombocytopaenia. In the context of placental anastomoses, monochorionic diamniotic twins are at risk of twin twin transfusion syndrome (TTTS), or partial forms including Twin Oligohydramnios Polyhydramnios Sequence (TOPS), differences in estimated weight (selective Intrauterine growth Retardation; sIUGR), or in fetal haemoglobin (Twin Anaemia Polycythaemia Sequence; TAPS). There is a very wide range of ischaemic and haemorrhagic injury in a focal as well as a global distribution. Acute twin twin transfusion may account for intraventricular haemorrhage in recipients and periventricular leukomalacia in donors but there are additional risk factors for focal embolism and cerebrovascular disease. The recipient has circulatory overload, with effects on systemic and pulmonary circulations which probably lead to systemic and pulmonary hypertension and even right ventricular outflow tract obstruction as well as the polycythaemia which is a risk factor for thrombosis and vasculopathy. The donor is hypovolaemic and has a reticulocytosis in response to the anaemia while maternal hypertension and diabetes may influence stroke risk. Understanding of the mechanisms, including the role of vasculopathy, in well studied conditions such as alloimmune thrombocytopaenia and monochorionic diamniotic twinning may lead to reduction of the burden of antenatally sustained cerebral palsy.  相似文献   
26.
27.
28.
OBJECTIVE: IGF-I and insulin are the main regulators of intrauterine and postnatal growth. Adipose tissue secreted cytokines are implicated in intrauterine growth. The relevant function of the adipocytokine visfatin is unknown. MATERIALS AND METHODS: Serum visfatin, IGF-I and insulin levels were measured by enzyme immunoassays in 40 singleton full-term fetuses and neonates on postnatal days 1(N1) and 4 (N4). RESULTS: No significant correlations exist between visfatin and IGF-I or insulin. N1 and N4 visfatin positively correlated with customized (adjusted) birth weight centiles (r=0.511, P=0.021, and r=0.597, P=0.005, respectively). Fetal and N1 IGF-I positively correlated with customized centiles (r=0.608, P<0.001 and r=0.485, P=0.006, respectively). Fetal insulin positively correlated with customized centiles (r=0.654, P=0.021). CONCLUSIONS: Potential implication of visfatin in fetal growth is probably not mediated by IGF-I or insulin. Although a more active role cannot be excluded, visfatin may simply represent a marker of fat accumulation.  相似文献   
29.
Sexual classification systems are based on precise and understandable definitions of sexual dysfunctions and are needed for investigative research, determination of diagnostic standards, and delineation of treatment strategies. The four major categories of sexual dysfunctions include disorders of sexual desire/interest, arousal, orgasm, and sexual pain. The purpose of this article is to review the major features, differences, and similarities of the six classification systems widely used in sexual medicine, including the International Classification of Diseases, the Diagnostic and Statistical Manual of Mental Disorders, the National Institute of Health Consensus Conference on Impotence, the American Foundation for Urologic Diseases, International Consensus Conference on Women's Sexual Dysfunction, and the First and Second International Consultations on Sexual Dysfunctions.  相似文献   
30.
BackgroundForce‐time integral (FTI) is an ablation marker of lesion quality and transmurality. A target FTI of 400 gram‐seconds (gs) has been shown to improve durability of pulmonary vein isolation, following atrial fibrillation ablation. However, relevant targets for cavotricuspid isthmus (CTI) ablation are lacking.HypothesisWe sought to investigate whether CTI ablation with 600 gs FTI lesions is associated with reduced rate of transisthmus conduction recovery compared to 400 gs lesions.MethodsFifty patients with CTI‐dependent flutter were randomized to ablation using 400 gs (FTI400 group, n = 26) or 600 gs FTI lesions (FTI600 group, n = 24). The study endpoint was spontaneous or adenosine‐mediated recovery of transisthmus conduction, after a 20‐min waiting period.ResultsThe study endpoint occurred in five patients (19.2%) in group FTI400 and in four patients (16.7%) in group FTI600, p = .81. First‐pass CTI block was similar in both groups (50% in FTI400 vs. 54.2% in FTI600, p = .77). There were no differences in the total number of lesions, total ablation time, procedure time and fluoroscopy duration between the two groups. There were no major complications in any group. In the total population, patients not achieving first‐pass CTI block had significantly higher rate of acute CTI conduction recovery, compared to those with first‐pass block (29.2% vs. 7.7% respectively, p = .048).ConclusionsCTI ablation using 600 gs FTI lesions is not associated with reduced spontaneous or adenosine‐mediated recurrence of transisthmus conduction, compared to 400 gs lesions.  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