全文获取类型
收费全文 | 5697篇 |
免费 | 471篇 |
国内免费 | 213篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 164篇 |
妇产科学 | 155篇 |
基础医学 | 790篇 |
口腔科学 | 71篇 |
临床医学 | 556篇 |
内科学 | 761篇 |
皮肤病学 | 78篇 |
神经病学 | 242篇 |
特种医学 | 233篇 |
外科学 | 592篇 |
综合类 | 774篇 |
预防医学 | 425篇 |
眼科学 | 109篇 |
药学 | 556篇 |
7篇 | |
中国医学 | 432篇 |
肿瘤学 | 370篇 |
出版年
2023年 | 53篇 |
2022年 | 90篇 |
2021年 | 138篇 |
2020年 | 126篇 |
2019年 | 88篇 |
2018年 | 119篇 |
2017年 | 109篇 |
2016年 | 99篇 |
2015年 | 182篇 |
2014年 | 194篇 |
2013年 | 244篇 |
2012年 | 361篇 |
2011年 | 373篇 |
2010年 | 273篇 |
2009年 | 269篇 |
2008年 | 280篇 |
2007年 | 301篇 |
2006年 | 256篇 |
2005年 | 202篇 |
2004年 | 152篇 |
2003年 | 160篇 |
2002年 | 155篇 |
2001年 | 117篇 |
2000年 | 98篇 |
1999年 | 56篇 |
1998年 | 52篇 |
1997年 | 43篇 |
1996年 | 42篇 |
1995年 | 54篇 |
1994年 | 30篇 |
1993年 | 48篇 |
1992年 | 59篇 |
1991年 | 81篇 |
1990年 | 51篇 |
1989年 | 67篇 |
1988年 | 77篇 |
1987年 | 67篇 |
1986年 | 83篇 |
1985年 | 88篇 |
1984年 | 60篇 |
1983年 | 50篇 |
1982年 | 36篇 |
1979年 | 40篇 |
1978年 | 27篇 |
1959年 | 51篇 |
1958年 | 105篇 |
1957年 | 108篇 |
1956年 | 79篇 |
1955年 | 82篇 |
1954年 | 67篇 |
排序方式: 共有6381条查询结果,搜索用时 15 毫秒
1.
多级图像对比度放大技术在膝关节摄影中的应用 总被引:1,自引:0,他引:1
目的:分析评价膝关节摄影中多级图像对比度放大技术(MUSICA)参数设定的成像效果,为实际临床应用提供理论指导。方法:随机抽取膝关节侧位软拷贝图像70例,以骨皮质、骨小梁、肌间隙、髌上囊、皮下脂肪为比对目标,由三位观察者对其显示情况进行分析,并对结果进行统计分析。结果:MUSICA处于较小值(0~2)时,适合于软组织显示,但图像锐利度欠缺;处于较高值时(4~6)适合于观察骨皮质、小梁等细节信息,但较多地出现伪影,共25例;处于2~4时整体影像对比度适中,如实反映人体密度结构。结论:作图像处理时应将MUSICA为2~4设定为常规,实际应用通常情况下可以选择该处理方法,但应根据具体要求适当调整MUSICA参数值。 相似文献
2.
3.
4.
5.
We report the case of a 26-year-old man affected by a symmetrical keratoderma localized to the interdigital spaces of the fingers. No occupational, traumatic, or irritant factors were discovered. Clinical and histological features were consistent with the diagnosis of symmetrical interdigital hyperkeratosis, a sporadic disorder described by Frei in 1926. We believe this condition to be less rare than the few cases reported in the literature would suggest. 相似文献
6.
M. Puka-Sundvall E. Gilland E. Bona A. Lehmann M. Sandberg H. Hagberg 《Metabolic brain disease》1996,11(2):109-123
The aim of this study was to investigate the possible role of excitatory amino acids (EAAs) and cysteine in the development of brain damage after hypoxia-ischemia (HI) in neonates. In a rat model of neonatal HI, changes in extracellular (ec) amino acids in cerebral cortex were measured with microdialysis and correlated with the extent of brain damage at the site of probe placement. Extracellular concentrations of glutamate, aspartate and cysteine increased during HI and remained elevated during reperfusion. During HI the pattern of EAA changes was the same in the infarcted, undamaged and border zone regions. During reperfusion, however, the ec concentrations of glutamate, aspartate and cysteine were higher in infarcted and border zone areas compared to undamaged tissue. HI also produced a slight increase of tissue concentration of cysteine and decrease of tissue concentration of glutamate in parietal cortex of the HI hemisphere. The effect of cysteine on brain damage induced by HI and glutamate was also investigated. A subtoxic dose of cysteine potentiated glutamate toxicity in the arcuate nucleus and enhanced brain infarction after HI in neonatal rats. The results show that in neonatal HI the extracellular levels of EAAs during HI are not directly related to brain injury but the EAA levels during reflow predict the extent of infarction. Cysteine increases HI-induced brain injury and potentiates glutamate toxicity in neonatal rats. Speculatively, elevated level of cysteine during reperfusion may participate in the excitotoxic cascade leading to brain injury. 相似文献
7.
Operative versus non-operative treatment of recent injuries to the ligaments of the knee. A prospective randomized study 总被引:3,自引:0,他引:3
R Sandberg B Balkfors B Nilsson N Westlin 《The Journal of bone and joint surgery. American volume》1987,69(8):1120-1126
Two hundred consecutively seen patients who had an injury to either the anterior cruciate ligament or the medial collateral ligament, or both, were randomly allocated to treatment by either conservative or a surgical regimen. Injuries to the medial collateral ligament could not be demonstrated to benefit from surgical treatment in any respect--with or without surgery the results were excellent. With injuries to the anterior cruciate ligament, recovery was more rapid without surgery but otherwise the results differed between the groups in only one respect: the pivot-shift test was more often positive after conservative treatment. The results were good in both treatment groups even though most of the patients who had an injury of the anterior cruciate ligament were somewhat less pleased with the outcome after a period of time. 相似文献
8.
Nutritional dwarfing refers to a condition in which maladaptive eating patterns play a primary role in poor linear growth and delayed pubertal development. The present controlled study assesses whether nutritionally dwarfed children and adolescents differ in their psychosocial adjustment from healthy children and adolescents of comparable height in ways that might account for their undernutrition. Children with nutritional dwarfing (n = 16) were compared by standardized questionnaires with a short-stature (ie, heights below the fifth percentile) control group composed of children and adolescents with constitutional growth delay and/or familial short stature (n = 31). Scores on a self-report screening questionnaire for eating disorders did not differentiate the groups. Moreover, the vast majority of nutritionally dwarfed patients expressed a desire to have a heavier physical appearance. Whereas the groups were generally similar in self-perceptions of domain-specific competencies and positive psychosocial adjustment, the parents of nutritionally dwarfed children reported that their children showed significantly fewer externalized behavior problems. These findings suggest the existence of an eating disturbance that compromises growth in childhood and/or adolescence which, unlike anorexia nervosa, is not associated with evidence of psychopathology. 相似文献
9.
10.
The ulcerogenic effect of five different salts of alprenolol were tested against placebo in a porcine oesophageal test model. The salts with high water solubility, such as the hydrochloride and the fumarate, gave rise to the highest plasma concentrations of alprenolol and evoked serious oesophageal lesions, while the salts with low solubility-the benzoate, maleate and sebacate-had no irritative effect on the oesophagus. The plasma levels of alprenolol were much higher following administration of alprenolol hydrochloride in the oesophagus than after an identical intraduodenal dose of the same salt possibly because of the avoidance of the first-pass degradation during oesophageal absorption. 相似文献