首页 | 官方网站   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   7436篇
  免费   622篇
  国内免费   30篇
医药卫生   8088篇
  2023年   69篇
  2021年   77篇
  2020年   79篇
  2019年   77篇
  2018年   149篇
  2017年   98篇
  2016年   109篇
  2015年   138篇
  2014年   194篇
  2013年   284篇
  2012年   257篇
  2011年   282篇
  2010年   174篇
  2009年   184篇
  2008年   261篇
  2007年   274篇
  2006年   240篇
  2005年   219篇
  2004年   228篇
  2003年   217篇
  2002年   182篇
  2001年   238篇
  2000年   213篇
  1999年   192篇
  1998年   118篇
  1997年   151篇
  1996年   130篇
  1995年   96篇
  1994年   120篇
  1993年   97篇
  1992年   171篇
  1991年   195篇
  1990年   202篇
  1989年   196篇
  1988年   177篇
  1987年   171篇
  1986年   168篇
  1985年   165篇
  1984年   130篇
  1983年   97篇
  1982年   89篇
  1981年   95篇
  1980年   68篇
  1979年   122篇
  1978年   88篇
  1977年   72篇
  1976年   65篇
  1975年   74篇
  1974年   61篇
  1972年   58篇
排序方式: 共有8088条查询结果,搜索用时 15 毫秒
11.
12.
Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml -1), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml -1) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-2 week-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis.  相似文献   
13.
14.
Clinical practice guidelines have emerged as a reality for medical practitioners over the past 20 years. Although virtually all groups interested in the development of practice guidelines hope for improvements in patient care, secondary expectations vary widely among those using them. Their use in daily practice by physicians has met with resistance from barriers including concerns of “cookbook” medicine, a loss of autonomy, and increased professional liability. The recent experience of the ACR in addressing these challenges illustrates that physicians are receptive to steps perceived to mitigate the risks accompanying the use of guidelines as well as to efforts to increase their understanding of implementing guidelines in clinical practice. The experiences of other medical societies and an inventory of future trends reveal additional challenges associated with the use of practice guidelines, as third parties look to guidelines as points of reference for gauging the performance of health care providers.  相似文献   
15.
AD  Giannoukas  N  Labropoulos  FCT  Smith  GS  Venables  JD  Beard  武婕 《中华脑血管病论坛》2005,3(5):555-560
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章.  相似文献   
16.
BACKGROUND: Neuroanatomic sexual dimorphisms have been correlated with behavioral differences between healthy men and women. We have reported higher orbitofrontal cortex to amygdala ratio (OAR) in women than men. Although gender differences in schizophrenia are evident clinically and correlate with neuroanatomic measures, their relationship to OAR has not been examined. METHODS: Magnetic resonance imaging was performed in 31 neuroleptic-na?ve schizophrenic patients (16 men) and 80 healthy volunteers (34 men), aged less than 50 years. An automated tissue segmentation procedure was combined with expert-guided parcellation of orbitofrontal and amygdala volumes. RESULTS: Men with schizophrenia had increased OAR relative to healthy men, whereas women had decreased OAR. Increased OAR in men with schizophrenia reflected abnormally low amygdala volumes, whereas decreased OAR in women reflected abnormally low orbitofrontal volumes. Less severe negative symptoms were associated with increased OAR in men but with decreased OAR in women. In men, increased amygdala volume was associated with greater symptom severity, whereas in women higher volumes of both amygdala and orbitofrontal regions were associated with lesser severity of negative symptoms. CONCLUSIONS: These opposite OAR abnormalities, whereby men show feminization and women masculinization, suggest gender-mediated effects of the underlying neuropathologic processes. The correlations with symptom severity suggest that neuroanatomic abnormalities in OAR reflect compensatory brain changes.  相似文献   
17.
18.
The effect of hydroxyethyl starch on pancreas preservation with cardioplegic histidine-tryptophan-ketoglutarate solution (HTK) was investigated. The study was performed using an in vitro reperfusion system of the porcine pancreas. During organ preservation pancreatic weight, arterial pressure, volume flow, and washout of amylase and lactate were quantified. Addition of hydroxyethyl starch did not affect arteriovenous volume flow or washout of amylase and lactate during protective perfusion after pancreas preparation. However, hydroxyethyl starch in HTK prevented an increase in pancreatic weight at the end of the protective perfusion (102.2 ± 4.55% vs 127.8 ± 4.62% in controls; p < 0.005) and after 24 h cold ischemia (72.9 ± 3.91 % vs. 83.5 ± 3.49 % in controls; p < 0.05). Hydroxyethyl starch did not affect postischemic organ quality assessed during reperfusion in a perfusion chamber by pancreatic vascular resistance, amylase and lactate release, insulin secretion, and oxygen consumption. We conclude that hydroxyethyl starch does not bring about any further improvement in immediate postischemic organ quality assessed in an in vitro reperfusion system.
Hydroxyäthylstärke bringt keine verbesserung der pankreaskonservierung mit HTK-Lösung
Zusammenfassung Der Effekt von Hydroxyäthylstärke auf die Pankreaskonservierung mit der kardioplegischen Histidin-Tryptophan-Ketoglutarat-Lösung (HTK) wurde untersucht. Die Studie wurde an einem Reperfusionssystem des in vitro perfundierten Pankreas vom Schwein durchgeführt. Während der Organprotektion wurden das Pankreasgewicht, der arterielle Perfusionsdruck, die Volumenstromstärke sowie Amylase und Laktat im Perfusat bestimmt. Der Zusatz von Hydroxyäthylstärke bewirkte keine Änderung der Volumenstromstärke oder der Amylase- und Laktatauswaschung aus dem Organ während der Protektion. Allerdings konnte eine Zunahme des Organgewichts am Ende der protektiven Perfusion (102,2 ± 4,55% vs. 127,8 ± 4,62%in Kontrollen; p < 0,005) und nach 24 h kalter Ischamie (72,9 ± 3,91 vs. 83,5 ± 3,49% in Kontrollen; p < 0,05) durch Hydroxyathylstärke in der HTK-Lösung verhindert werden. Hydroxyäthylstärke hatte keinen Einfluß auf die postischämische Organqualität, die während der Reperfusion in einer Perfusionskammer anhand von Gefäßwiderstand, Amylase- und Laktatfreisetzung, Insulinsekretion und Sauerstoffverbrauch abgeschätzt wurde. Wir schließen daraus, daß Hydroxyäthylstärke die sofort nach einer Ischämie in einem In-vitro-Reperfusionssystem bestimmte Pankreasfunktion nicht weiter verbessert.
  相似文献   
19.
BACKGROUND: In view of the inconclusive reports in the literature about the response to neuroleptics of chronic schizophrenics with negative symptoms, the authors further evaluated this issue. METHOD: A sample of 30 ambulatory chronic schizophrenics meeting DSM-III-R criteria who had to a marked degree at least two negative symptoms of the five on the Scale for the Assessment of Negative Symptoms (SANS) received various therapeutic dosages of thiothixene for 3 months. The average dose was 26.75 mg/day. Subjects were periodically evaluated with the Brief Psychiatric Rating Scale, Negative Symptoms Rating Scale (a modified version of the SANS), and the Randt Memory Test. The time effect on treatment was calculated by repeated measures of analysis of variance. The relationship between the positive and negative symptoms was tested by an analysis of covariance. RESULTS: Both negative and positive symptoms improved with treatment. The negative symptoms tended to respond to treatment predominantly independently of the positive ones. At the end of the study, 63% (N = 19) of patients had improved moderately, 16% (N = 5) had improved slightly, and 20% (N = 6) had not improved. CONCLUSION: The data require further support from a long-term follow-up study that may show the extent to which these gains are maintained over time.  相似文献   
20.
Pediatric knee MR imaging: pattern of injuries in the immature skeleton   总被引:3,自引:0,他引:3  
  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-23

京公网安备 11010802026262号