全文获取类型
收费全文 | 1532篇 |
免费 | 158篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 56篇 |
妇产科学 | 31篇 |
基础医学 | 252篇 |
口腔科学 | 15篇 |
临床医学 | 219篇 |
内科学 | 319篇 |
皮肤病学 | 29篇 |
神经病学 | 198篇 |
特种医学 | 55篇 |
外科学 | 161篇 |
综合类 | 33篇 |
一般理论 | 6篇 |
预防医学 | 155篇 |
眼科学 | 12篇 |
药学 | 89篇 |
中国医学 | 3篇 |
肿瘤学 | 48篇 |
出版年
2023年 | 14篇 |
2021年 | 30篇 |
2020年 | 21篇 |
2019年 | 21篇 |
2018年 | 22篇 |
2017年 | 21篇 |
2016年 | 27篇 |
2015年 | 41篇 |
2014年 | 41篇 |
2013年 | 49篇 |
2012年 | 46篇 |
2011年 | 65篇 |
2010年 | 47篇 |
2009年 | 36篇 |
2008年 | 57篇 |
2007年 | 69篇 |
2006年 | 57篇 |
2005年 | 54篇 |
2004年 | 45篇 |
2003年 | 54篇 |
2002年 | 48篇 |
2001年 | 45篇 |
2000年 | 46篇 |
1999年 | 36篇 |
1998年 | 29篇 |
1997年 | 20篇 |
1996年 | 31篇 |
1995年 | 24篇 |
1994年 | 23篇 |
1993年 | 21篇 |
1992年 | 25篇 |
1991年 | 47篇 |
1990年 | 33篇 |
1989年 | 23篇 |
1988年 | 29篇 |
1987年 | 30篇 |
1986年 | 19篇 |
1985年 | 27篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1980年 | 21篇 |
1979年 | 16篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1975年 | 13篇 |
1974年 | 16篇 |
1972年 | 10篇 |
1968年 | 10篇 |
排序方式: 共有1693条查询结果,搜索用时 156 毫秒
121.
122.
123.
124.
125.
126.
127.
Metin N. Gurcan Tony Pan Ashish Sharma Tahsin Kurc Scott Oster Stephen Langella Shannon Hastings Khan M. Siddiqui Eliot L. Siegel Joel Saltz 《Journal of digital imaging》2007,20(2):160-171
This paper describes a Grid-aware image reviewing system (GridIMAGE) that allows practitioners to (a) select images from multiple geographically distributed digital imaging and communication in medicine (DICOM) servers, (b) send those images to a specified group of human readers and computer-assisted detection (CAD) algorithms, and (c) obtain and compare interpretations from human readers and CAD algorithms. The currently implemented system was developed using the National Cancer Institute caGrid infrastructure and is designed to support the identification of lung nodules on thoracic computed tomography. However, the infrastructure is general and can support any type of distributed review. caGrid data and analytical services are used to link DICOM image databases and CAD systems and to interact with human readers. Moreover, the service-oriented and distributed structure of the GridIMAGE framework enables a flexible system, which can be deployed in an institution (linking multiple DICOM servers and CAD algorithms) and in a Grid environment (linking the resources of collaborating research groups). GridIMAGE provides a framework that allows practitioners to obtain interpretations from one or more human readers or CAD algorithms. It also provides a mechanism to allow cooperative imaging groups to systematically perform image interpretation tasks associated with research protocols. 相似文献
128.
T. S. Juss E. Maywood A. P. Walker J. Herbert M. H. Hastings 《Journal of neuroendocrinology》1991,3(5):461-467
The aim of this study was to investigate the influence of inhibitory photoperiods upon opioidergic function, as determined by changes in the hypothalamic content of β-endorphin and the luteinizing hormone response to opioidergic receptor blockade, in the male Syrian hamster over the course of gonadal involution and spontaneous gonadal recrudescence. Animals exposed to an 8 h light: 16 h dark cycle (8L: 16D) for 14 weeks underwent gonadal regression. Regression was also observed in animals held for 7 weeks on one of a range of short daylengths of between 11.5 h and 13.5 h, the degree of atrophy being greatest in those animals on the shortest daylength. The tissue concentration of β-endorphin within the mediobasal hypothalamus was significantly higher in animals exposed to 8L: 16D for 14 weeks than in gonadally active controls held on long days (16L: 8D). Exposure to photoperiods of less than 13.5 h for 7 weeks also caused a significant increase in the β-endorphin content of the mediobasal hypothalamus and there was a positive correlation between the concentration of β-endorphin, the degree of gonadal atrophy and the shortness of the photoperiod. Endorphin levels within the preoptic area were not affected by photoperiodic treatments. Exposure of intact animals to 8L: 16D for 12 weeks caused gonadal atrophy and an associated loss of the luteinizing hormone responses to both naloxone and castration. Castrated animals receiving testosterone replacement (cast + T) also exhibited photoinhibition, in the form of reduced serum levels of luteinizing hormone, and this was similarly accompanied by a loss of sensitivity to naloxone and to withdrawal of steroid. Prolonged exposure to 8L:16D led to spontaneous reactivation of the gonadotrophic axis as a consequence of the development of scotorefractoriness. In both gondally intact animals and in cast + T groups, this was associated with a restoration, in parallel, of the luteinizing hormone responses to naloxone and to castration/ steroid withdrawal. The time-course of the restoration of the response to steroid withdrawal in castrates was not significantly different to that observed in intact animals. The luteinizing hormone response to naloxone took significantly longer to redevelop in cast + T groups than it did in gonadally intact animals. The data demonstrate that central opioid systems are sensitive to photoperiod and are consistent with the hypothesis that opioids are involved in the neuroendocrine regulation of reproductive responses to daylength. 相似文献
129.
A continuous care team provides ongoing treatment for chronic mentally ill patients at a community mental health center in an inner-city area. The team, which consists of a nurse-social worker, a psychiatrist, four clinicians, and an addictions counselor, uses aggressive outreach and remains in charge of treatment while the patient is hospitalized. Preliminary outcomes for 32 of 39 patients treated during the first 15 months of the program included increased rates of treatment compliance, decreased frequency of crises, and decreased frequency and duration of hospitalization. However, substance abuse continued to be a problem and was negatively correlated with improvement. 相似文献
130.
IM Gardiner F Ahmed TJ Steiner A McBain C Kennard J de Belleroche 《Cephalalgia : an international journal of headache》1998,18(4):192-196
The project was an investigation into whether changes in the expression of G-proteins underlie altered cell signaling in migraine and cluster headache. The basis for this assumption is that altered physiological responses are seen in migraineurs and that differences in cell signaling are detected biochemically in various cell types isolated from peripheral blood. Levels of three G-protein mRNAs—Gsα, Giα, and Gqα were quantified in lymphocytes from clinically well-defined migraine and cluster headache patients and correlated with headache type and influence of drug treatment. Giα mRNA was reduced by 50% in all migraine patients compared with control subjects; similarly in patients with or without aura, in patients with a migraine headache at the time of sampling, and patients in a quiescent state. No reduction in the levels of Gsα or Gqα mRNA were seen in migraine patients. A smaller reduction was seen in cluster headache patients, most marked in those without medication. Levels of Gsα. mRNA were significantly reduced in cluster headache patients compared with migraine patients. The marked down-regulation of Giα mRNA in migraine, whether quiescent or acute, indicates either an adaptive response to headache in this group of patients or that low levels of Giα mRNA make individuals more susceptible to migraine. 相似文献