全文获取类型
收费全文 | 56341篇 |
免费 | 4559篇 |
国内免费 | 173篇 |
专业分类
耳鼻咽喉 | 818篇 |
儿科学 | 1573篇 |
妇产科学 | 973篇 |
基础医学 | 7642篇 |
口腔科学 | 708篇 |
临床医学 | 5929篇 |
内科学 | 11503篇 |
皮肤病学 | 601篇 |
神经病学 | 5470篇 |
特种医学 | 2015篇 |
外科学 | 9079篇 |
综合类 | 1283篇 |
现状与发展 | 1篇 |
一般理论 | 49篇 |
预防医学 | 4762篇 |
眼科学 | 736篇 |
药学 | 3877篇 |
中国医学 | 62篇 |
肿瘤学 | 3992篇 |
出版年
2023年 | 320篇 |
2022年 | 570篇 |
2021年 | 1282篇 |
2020年 | 760篇 |
2019年 | 1214篇 |
2018年 | 1478篇 |
2017年 | 998篇 |
2016年 | 1153篇 |
2015年 | 1398篇 |
2014年 | 1862篇 |
2013年 | 2513篇 |
2012年 | 4094篇 |
2011年 | 4150篇 |
2010年 | 2296篇 |
2009年 | 2121篇 |
2008年 | 3521篇 |
2007年 | 3712篇 |
2006年 | 3566篇 |
2005年 | 3573篇 |
2004年 | 3191篇 |
2003年 | 3024篇 |
2002年 | 2802篇 |
2001年 | 802篇 |
2000年 | 666篇 |
1999年 | 732篇 |
1998年 | 652篇 |
1997年 | 557篇 |
1996年 | 453篇 |
1995年 | 434篇 |
1994年 | 405篇 |
1993年 | 388篇 |
1992年 | 515篇 |
1991年 | 433篇 |
1990年 | 411篇 |
1989年 | 415篇 |
1988年 | 355篇 |
1987年 | 332篇 |
1986年 | 297篇 |
1985年 | 305篇 |
1984年 | 274篇 |
1983年 | 248篇 |
1982年 | 236篇 |
1981年 | 215篇 |
1980年 | 172篇 |
1979年 | 189篇 |
1978年 | 167篇 |
1977年 | 160篇 |
1976年 | 153篇 |
1974年 | 134篇 |
1973年 | 148篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
OBJECTIVE: Previous research has suggested that organisational change can contribute to stress-related outcomes for workers. Burnout, one such stress-related outcome, has been conceptualised as a multidimensional construct consisting of emotional exhaustion, depersonalisation and reduced personal accomplishment. Many health care organisations have undergone substantial organisational change over the last decade. The purpose of this study was to assess levels of burnout in nurses and to ascertain if there were individual or work characteristics that were associated with this syndrome. DESIGN: Randomised survey methodology. SETTING: Registered nurses (Division 1) in Victoria who were ANF members. SUBJECTS: A random sample of 574 Victorian ANF nurse members. MAIN OUTCOME MEASURES: The assessment of levels of burnout in Victorian ANF nurse members and the identification of individual or work characteristics that may be associated with it. RESULTS: Victorian ANF nurse members exhibited lower depersonalisation and higher personal accomplishment compared to medical and overall normative data. Increasing age and fewer working hours were associated with lower levels of emotional exhaustion and depersonalisation. Working overtime was positively associated with emotional exhaustion however further analyses demonstrated that those who worked overtime voluntarily did not differ from workers not working overtime. However feeling pressured/expected to work overtime was positively associated with emotional exhaustion and depersonalisation. CONCLUSION: Victorian ANF nurse members were not experiencing high levels of burnout. However the study highlighted the need for health care management to recognise the importance of working reasonable hours and in particular, to understand the potential detrimental effect that having to work pressured or unexpected overtime has on staff. 相似文献
32.
A. Ian Smith Catherine A. Wallace Lain J. Clarke John W. Funder 《Journal of neuroendocrinology》1989,1(5):357-362
In the sheep, unlike many other species, a significant proportion (>25%) of immunoreactive β-endorphin in the anterior pituitary is post-translationally modified to opioid-inactive, α-N-acetylated forms. In a study to determine the precise molecular nature of α-N-acetylated β-endorphin immunoreactivity, we noted a striking difference in high-performance liquid chromatography profiles of anterior pituitary extracts between sheep killed on the farm, and age-, sex- and strain-matched slaughterhouse animals. These altered patterns of a-N-acetylated β-endorphin processing were reproduced in farm animals by chronic (≤ 4 days) treatment with the synthetic glucocorticoid dexamethasone; in contrast dexamethasone had no effect on a-N-acetylated β-endorphin processing in hypothalamo-pituitary disconnected sheep. These data suggest that (1) the change in processing is a stress response, mediated by prolonged glucocorticoid exposure, (2) this effect is central, rather than a direct effect on the pituitary, and (3) the relative abundance of various peptide sequences in slaughterhouse-derived material may not reflect their abundance under more physiological conditions. 相似文献
33.
Exposure of ZR-75-1 human breast cancer cells for 48 h to human recombinant interferon alpha (IFN alpha) resulted in increased expression of oestrogen receptors as measured in a whole cell binding assay. This effect was inversely proportional to dose being significant following treatment with 10-100 IU IFN ml-1 and was only observed at a low initial cell plating density. The extent of the increase in oestrogen receptor levels ranged from 1.2- to 7.2-fold following treatment with 10 IU IFN ml-1. No increase in progesterone receptor expression was observed under the same experimental conditions. Concentrations of IFN which increased oestrogen receptor levels had no effect on cell proliferation. IFN (500 IU ml-1) inhibited cell proliferation and the combination of this treatment with tamoxifen (2 microM) had a greater anti-proliferative effect than either drug alone although there was no evidence of synergism. However, a 5-day pretreatment of cells with IFN (10 IU ml-1) markedly sensitised them to the growth-inhibiting effect of a subsequent 6-day exposure to tamoxifen. 相似文献
34.
Dave F Clarke James W Wheless Monica M Chacon Joshua Breier Mary-Kay Koenig Mark McManis Edward Castillo James E Baumgartner 《Seizure》2007,16(6):545-553
Corpus callosotomy has a long history as a palliative treatment for intractable epilepsy. Identification of a single epileptogenic zone is critical to performing successful resective surgery. We describe three patients in which corpus callosotomy allowed recognition of unapparent seizure foci, leading to subsequent successful resection. We retrospectively reviewed our epilepsy surgery database from 2003 to 2005 for children who had a prior callosotomy and were candidates for focal resection. All underwent magnetic resonance imaging and scalp video electroencephalograph monitoring, and two had magnetoencephalography, electrocorticography and/or intracranial video electroencephalograph monitoring. The children were 8 and 9 years old, and seizure onset varied from early infancy to early childhood. One child had a history of head trauma preceding seizure onset, one had a large intracerebral infarct and dysplastic cortex in the contralateral frontal lobe, and the other had an anterior temporal lobe resection without improvement in seizure frequency. After medical management failed, callosotomy was performed with the expectation of decreasing the seizure types affecting both hemispheres. Following transection of the callosal fibers, a single focus was recognized and resected, with resultant dramatic improvement in seizure control. In medically refractory epilepsy, where rapid secondary bisynchrony is suspected but the electroencephalograph is non-localizing, callosotomy should be considered as a means of treating generalized seizure types, but may also assist in identifying potentially operable seizure foci. Study limitations include its retrospective nature and cohort size. The findings, however, suggest the need for prospective, systematic, well-controlled studies of the use of corpus callostomy in this intractable patient population. 相似文献
35.
36.
37.
Nathan J Koewler Katie T Freeman Ryan J Buus Monica B Herrera Juan M Jimenez-Andrade Joseph R Ghilardi Christopher M Peters Lucy J Sullivan Michael A Kuskowski Jack L Lewis Patrick W Mantyh 《Journal of bone and mineral research》2007,22(11):1732-1742
A closed femur fracture pain model was developed in the C57BL/6J mouse. One day after fracture, a monoclonal antibody raised against nerve growth factor (anti-NGF) was delivered intraperitoneally and resulted in a reduction in fracture pain-related behaviors of approximately 50%. Anti-NGF therapy did not interfere with bone healing as assessed by mechanical testing and histomorphometric analysis. INTRODUCTION: Current therapies to treat skeletal fracture pain are limited. This is because of the side effect profile of available analgesics and the scarcity of animal models that can be used to understand the mechanisms that drive this pain. Whereas previous studies have shown that mineralized bone, marrow, and periosteum are innervated by sensory and sympathetic fibers, it is not understood how skeletal pain is generated and maintained even in common conditions such as osteoarthritis, low back pain, or fracture. MATERIALS AND METHODS: In this study, we characterized the pain-related behaviors after a closed femur fracture in the C57BL/6J mouse. Additionally, we assessed the effect of a monoclonal antibody that binds to and sequesters nerve growth factor (anti-NGF) on pain-related behaviors and bone healing (mechanical properties and histomorphometric analysis) after fracture. RESULTS: Administration of anti-NGF therapy (10 mg/kg, days 1, 6, and 11 after fracture) resulted in a reduction of fracture pain-related behaviors of approximately 50%. Attenuation of fracture pain was evident as early as 24 h after the initial dosing and remained efficacious throughout the course of fracture pain. Anti-NGF therapy did not modify biomechanical properties of the femur or histomorphometric indices of bone healing. CONCLUSIONS: These findings suggest that therapies that target NGF or its cognate receptor(s) may be effective in attenuating nonmalignant fracture pain without interfering with bone healing. 相似文献
38.
39.
40.