全文获取类型
收费全文 | 17857篇 |
免费 | 1602篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 174篇 |
儿科学 | 636篇 |
妇产科学 | 560篇 |
基础医学 | 2286篇 |
口腔科学 | 188篇 |
临床医学 | 2616篇 |
内科学 | 3013篇 |
皮肤病学 | 240篇 |
神经病学 | 1782篇 |
特种医学 | 417篇 |
外科学 | 2013篇 |
综合类 | 339篇 |
一般理论 | 28篇 |
预防医学 | 2333篇 |
眼科学 | 201篇 |
药学 | 1022篇 |
中国医学 | 17篇 |
肿瘤学 | 1622篇 |
出版年
2023年 | 149篇 |
2022年 | 260篇 |
2021年 | 551篇 |
2020年 | 337篇 |
2019年 | 554篇 |
2018年 | 637篇 |
2017年 | 455篇 |
2016年 | 492篇 |
2015年 | 509篇 |
2014年 | 740篇 |
2013年 | 957篇 |
2012年 | 1432篇 |
2011年 | 1505篇 |
2010年 | 760篇 |
2009年 | 713篇 |
2008年 | 1172篇 |
2007年 | 1186篇 |
2006年 | 1191篇 |
2005年 | 1184篇 |
2004年 | 919篇 |
2003年 | 836篇 |
2002年 | 759篇 |
2001年 | 215篇 |
2000年 | 185篇 |
1999年 | 160篇 |
1998年 | 129篇 |
1997年 | 95篇 |
1996年 | 86篇 |
1995年 | 73篇 |
1994年 | 72篇 |
1993年 | 50篇 |
1992年 | 87篇 |
1991年 | 64篇 |
1990年 | 83篇 |
1989年 | 89篇 |
1988年 | 75篇 |
1987年 | 68篇 |
1986年 | 69篇 |
1985年 | 65篇 |
1984年 | 45篇 |
1983年 | 36篇 |
1982年 | 33篇 |
1981年 | 29篇 |
1980年 | 29篇 |
1979年 | 45篇 |
1978年 | 25篇 |
1972年 | 24篇 |
1971年 | 24篇 |
1970年 | 22篇 |
1969年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Heather L. Brown 《Journal of emergency nursing》2021,47(2):321-325
The coronavirus 2019 pandemic has affected almost every aspect of health care delivery in the United States, and the emergency medicine system has been hit particularly hard while dealing with this public health crisis. In an unprecedented time in our history, medical systems and clinicians have been asked to be creative, flexible, and innovative, all while continuing to uphold the important standards in the US health care system. To continue providing quality services to patients during this extraordinary time, care providers, organizations, administrators, and insurers have needed to alter longstanding models and procedures to respond to the dynamics of a pandemic. The Emergency Medicine Treatment and Active Labor Act of 1986, or EMTALA, is 1 example of where these alterations have allowed health care facilities and clinicians to continue their work of caring for patients while protecting both the patients and the clinicians themselves from infectious exposures at the same time. 相似文献
2.
3.
Metabolism describes the series of chemical reactions that are concerned with the provision of energy to biological systems. They may be divided into reactions involved in energy yield (catabolism: demand exceeds supply), and energy storage (anabolism: supply exceeds demand). Regulation of these pathways is critical for homeostasis, and derangements in metabolism are seen in a wide variety of pathological processes. Understanding metabolism is key to the treatment of many diseases, notably diabetes, as well as underpinning clinical nutritional support. 相似文献
4.
Monique G. Kumar M.Phil. M.D. Heather Ciliberto M.D. Susan J. Bayliss M.D. 《Pediatric dermatology》2015,32(2):198-200
Pediatric trachyonychia is an acquired nail disease that can cause distress to families. It is a poorly understood disease, and long‐term follow‐up data are lacking. We present an institutional review of 11 children with isolated pediatric trachyonychia followed over time. Children with the diagnosis of pediatric trachyonychia were identified and invited to participate. Pictures were taken on follow‐up and a questionnaire was answered. Exclusion criteria include having another diagnosis at the initial visit that causes nail dystrophy. Eleven patients with the diagnosis of pediatric trachyonychia were available for follow‐up. The mean age of appearance was 2.7 years (range 2–7 yrs) and the average follow‐up was 66 months (range 10–126 mos). Nine patients were treated with potent topical corticosteroids, one used only petrolatum, and one took vitamin supplements. One patient was found to have an additional skin and hair diagnosis of alopecia areata on follow‐up. On follow‐up, 82% noted improvement of the nails, whereas 18% noted no change. A majority of cases of pediatric trachyonychia are isolated and improve with time, regardless of treatment. 相似文献
5.
Sourajit M.Mustafi Jaroslaw Harezlak Chandana Kodiweera Jennifer S.Randolph James C.Ford Heather A.Wishart Yu-Chien Wu 《中国神经再生研究》2019,(1)
Multiple sclerosis is a neurodegenerative and inflammatory disease, a hallmark of which is demyelinating lesions in the white matter. We hypothesized that alterations in white matter microstructures can be non-invasively characterized by advanced diffusion magnetic resonance imaging. Seven diffusion metrics were extracted from hybrid diffusion imaging acquisitions via classic diffusion tensor imaging, neurite orientation dispersion and density imaging, and q-space imaging. We investigated the sensitivity of the diffusion metrics in 36 sets of regions of interest in the brain white matter of six female patients(age 52.8 ± 4.3 years) with multiple sclerosis. Each region of interest set included a conventional T2-defined lesion, a matched perilesion area, and normal-appearing white matter. Six patients with multiple sclerosis(n = 5) or clinically isolated syndrome(n = 1) at a mild to moderate disability level were recruited. The patients exhibited microstructural alterations from normal-appearing white matter transitioning to perilesion areas and lesions, consistent with decreased tissue restriction, decreased axonal density, and increased classic diffusion tensor imaging diffusivity. The findings suggest that diffusion compartment modeling and q-spa ce analysis appeared to be sensitive for detecting subtle microstructural alterations between perilesion areas and normal-appearing white matter. 相似文献
6.
ABSTRACTAlthough exclusive breastfeeding has been linked to lower rates of postnatal HIV transmission compared to nonexclusive breastfeeding, mechanisms underlying this are unclear. Across a longitudinally sampled cohort of South African infants, we showed that exclusively breastfed (EBF) infants had altered gut bacterial communities when compared to nonexclusively breastfed (NEBF) infants, as well as reduced peripheral CD4 + T cell activation and lowered chemokine and chemokine receptor expression in the oral mucosa. We further demonstrated that the relative abundance of key taxa was correlated with peripheral CD4 + T cell activation. Here, we supplement those findings by using compositional data analyses to identify shifts in the abundance of several Bifidobacteria strains relative to select strains of Escherichia, Bacteroides, and others that are associated with the transition to NEBF. We illustrate that the abundance ratio of these taxa is tightly correlated with feeding modality and is a strong predictor of peripheral T cell activation. More broadly, we discuss our study in the context of novel developments and explore future directions for the field. 相似文献
7.
Heather R. Nolan Juan Gurria Jose L. Peiro Sammy Tabbah Ramiro Diaz-Primera William Polzin Mounira Habli Foong-Yen Lim 《Journal of pediatric surgery》2019,54(6):1153-1158
PurposeCongenital high airway obstruction syndrome (CHAOS) is a devastating fetal condition of complete airway discontinuity resulting in significant hydrops and extreme lung hyperplasia. It is universally fatal with survival reported only in the rare spontaneous fistulization or EXIT intervention (Ex Utero Intrapartum Treatment). Even in these cases, mortality remains high, and current investigations are targeting prenatal interventions. This report describes our experience with management and fetal interventions for CHAOS, including laser laryngotomy.MethodsWe retrospectively reviewed all patients diagnosed with CHAOS at a single academic institution between 2006 and 2017.ResultsFifteen patients were identified. Eight had obstruction at the trachea and seven at the larynx. In the laryngeal obstructions, three expired shortly after birth, and one survived after spontaneous fistulization and subsequent EXIT to tracheostomy. The remaining three underwent in-utero treatment with laser laryngotomy. One had preterm premature rupture of membranes (PPROM), delivered 3 days post-operatively, and died. Two underwent EXIT to tracheostomy with one surviving to discharge and is currently 2 years old.ConclusionOur study demonstrates the outcomes of a large series of patients diagnosed with CHAOS. While mortality remains high, options for fetal intervention are being explored to allow alterations in the prenatal natural history and improve postnatal outcomes.Type of StudyRetrospective Treatment Study.Level of EvidenceLevel IV. 相似文献
8.
Heather M Arthur Christine Patterson James A Stone 《European journal of cardiovascular prevention and rehabilitation》2006,13(1):3-9
BACKGROUND: Presently, complementary and alternative medicine, including both therapies and herbal/oral supplements, is used globally. Few studies have examined the use of specific therapies, separate from herbal/oral supplements, in cardiac rehabilitation. This paper presents a systematic evaluation of current research evidence related to use of specific complementary and alternative medicine therapies in secondary prevention of cardiovascular disease, with a view to making recommendations for cardiac rehabilitation. DESIGN AND METHODS: A literature search was conducted using complementary and alternative medicine websites, Medline, Allied and Complementary Medicine, CINAHL, Cochrane databases, EMBASE, SportDiscus, Clinical Evidence, and Evidence-Based Practice to locate research-based scientific evidence related to the use of complementary and alternative medicine in cardiac rehabilitation. Search keywords included heart, cardiac, cardiovascular, coronary, myocardial and rehabilitation, combined with particular therapies. Herbal/oral supplements were not included in this evaluation. RESULTS: Some complementary and alternative medicine therapies may be useful to patients by themselves or coupled with traditional cardiac rehabilitation. Tai chi, as a complement to existing exercise interventions, can be utilized for low and intermediate risk patients. transcendental meditation may be used as a stress reduction technique. There was insufficient evidence found for the use of acupuncture or chelation therapy in cardiac rehabilitation or secondary prevention. CONCLUSIONS: Some complementary and alternative medicine therapies hold promise for patients in cardiac rehabilitation. Further research is essential, however, in all areas of complementary and alternative medicine to confirm its usefulness as an adjunct to cardiac rehabilitation. 相似文献
9.
10.