全文获取类型
收费全文 | 2106056篇 |
免费 | 163033篇 |
国内免费 | 7314篇 |
专业分类
耳鼻咽喉 | 27825篇 |
儿科学 | 63084篇 |
妇产科学 | 55891篇 |
基础医学 | 291717篇 |
口腔科学 | 60794篇 |
临床医学 | 187348篇 |
内科学 | 424819篇 |
皮肤病学 | 48007篇 |
神经病学 | 170015篇 |
特种医学 | 85252篇 |
外国民族医学 | 347篇 |
外科学 | 335075篇 |
综合类 | 46380篇 |
现状与发展 | 3篇 |
一般理论 | 627篇 |
预防医学 | 158142篇 |
眼科学 | 45926篇 |
药学 | 154299篇 |
8篇 | |
中国医学 | 4050篇 |
肿瘤学 | 116794篇 |
出版年
2018年 | 20489篇 |
2016年 | 18897篇 |
2015年 | 21270篇 |
2014年 | 29451篇 |
2013年 | 43901篇 |
2012年 | 55742篇 |
2011年 | 59356篇 |
2010年 | 36429篇 |
2009年 | 35388篇 |
2008年 | 56382篇 |
2007年 | 59867篇 |
2006年 | 61482篇 |
2005年 | 59398篇 |
2004年 | 56905篇 |
2003年 | 55247篇 |
2002年 | 53164篇 |
2001年 | 109173篇 |
2000年 | 112703篇 |
1999年 | 94140篇 |
1998年 | 25643篇 |
1997年 | 22663篇 |
1996年 | 23627篇 |
1995年 | 23196篇 |
1994年 | 21581篇 |
1993年 | 20123篇 |
1992年 | 75584篇 |
1991年 | 73114篇 |
1990年 | 70594篇 |
1989年 | 67907篇 |
1988年 | 62641篇 |
1987年 | 61233篇 |
1986年 | 57585篇 |
1985年 | 55464篇 |
1984年 | 41125篇 |
1983年 | 34776篇 |
1982年 | 20244篇 |
1981年 | 17948篇 |
1980年 | 16827篇 |
1979年 | 36824篇 |
1978年 | 25886篇 |
1977年 | 22022篇 |
1976年 | 19810篇 |
1975年 | 21086篇 |
1974年 | 25063篇 |
1973年 | 23855篇 |
1972年 | 22333篇 |
1971年 | 20802篇 |
1970年 | 19289篇 |
1969年 | 18073篇 |
1968年 | 16669篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Patricia A Wilkosz Sachiko Miyahara Oscar L Lopez Steven T Dekosky Robert A Sweet 《The American journal of geriatric psychiatry》2006,14(4):352-360
BACKGROUND: Psychotic symptoms in Alzheimer disease (AD+P) identify a heritable phenotype associated with more rapid cognitive decline. The authors have proposed that AD+P is itself a composite of a misidentification and a paranoid subtype with increased cognitive impairment restricted to the misidentification type. Most prior studies of the clinical correlates of AD+P have been limited, however, by the inclusion of prevalent cases. METHODS: Subjects with possible or probable AD or mild cognitive impairment (MCI) without psychosis at study entry were assessed at the time of initial presentation and then annually. Psychotic symptoms were assessed using the CERAD Behavioral Rating Scale. Survival analyses used Cox proportional hazard models with time-dependent covariates to examine the predictors of psychosis onset. RESULTS: A total of 288 subjects completed at least one follow-up examination. Mean duration of follow-up was 22.1 months. The incidence of psychosis was 0.19 per person-year. Cognitive impairment was associated with onset of psychosis, largely as a result of its association with onset of the misidentification, but not the paranoid, subtype. Including psychotropic medication use in the model revealed an association of antidepressant use with the onset of psychosis. This latter association appeared to arise from an underlying association between depression and the risk of psychosis onset rather than from antidepressant treatment. CONCLUSION: These findings are consistent with the hypothesis that the misidentification and the paranoid subtypes each define a more biologically homogeneous group than AD+P as a whole. Further exploration of the relationship between depressive symptoms and psychosis in patients with AD is warranted. 相似文献
53.
54.
55.
56.
57.
P E Santos E Piontelli Y R Shea M L Galluzzo S M Holland M E Zelazko S D Rosenzweig 《Medical mycology》2006,44(8):749-753
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients. 相似文献
58.
59.
60.
F. Spöler M. Först Y. Marquardt D. Hoeller H. Kurz H. Merk F. Abuzahra 《Skin research and technology》2006,12(4):261-267
BACKGROUND: Three dimensional skin equivalents are widely used in dermatopharmacological and toxicological studies and as autologous transplants in wound healing. In pharmacology, there is tremendous need for monitoring the response of engineered skin equivalents to external treatment. Transplantation of skin equivalents for wound healing requires careful verification of their quality prior to transplantation. Optical coherence tomography (OCT) is a non-contact, non-destructive imaging technique for living tissues offering the potential to fulfill these needs. This work presents an analysis of OCT for high-resolution monitoring of skin equivalents at different stages during the culture process. METHODS: We developed a high-resolution OCT imaging setup based on a commercially available OCT system. A broadband femtosecond laser light source replaces the original superluminescence diode. Tomograms of living skin equivalents were recorded with an axial resolution of 3 mum and correlated with histology and immunofluorescence images. Comparison with standard low-resolution OCT is presented to emphasize the advantages of high-resolution OCT for this application. RESULTS: OCT is particularly able to distinguish between different layers of skin equivalents including stratum corneum, epidermal and dermal layer as well as the basement membrane zone. The high-resolution OCT scans correlate closely with two key benchmarks, histology and immunofluorescence imaging. CONCLUSIONS: This study clearly demonstrates the benefits of high-resolution OCT for identifying living tissue structure and morphology. Compared with the current gold standard histology, OCT offers non-destructive tissue imaging, enabling high-resolution evaluation of living tissue morphology and structure as it evolves. 相似文献