全文获取类型
收费全文 | 35336篇 |
免费 | 2740篇 |
国内免费 | 95篇 |
专业分类
耳鼻咽喉 | 339篇 |
儿科学 | 1050篇 |
妇产科学 | 905篇 |
基础医学 | 5389篇 |
口腔科学 | 482篇 |
临床医学 | 5022篇 |
内科学 | 6316篇 |
皮肤病学 | 702篇 |
神经病学 | 3940篇 |
特种医学 | 811篇 |
外科学 | 3257篇 |
综合类 | 277篇 |
现状与发展 | 1篇 |
一般理论 | 33篇 |
预防医学 | 3765篇 |
眼科学 | 609篇 |
药学 | 2331篇 |
中国医学 | 42篇 |
肿瘤学 | 2900篇 |
出版年
2024年 | 32篇 |
2023年 | 280篇 |
2022年 | 431篇 |
2021年 | 901篇 |
2020年 | 601篇 |
2019年 | 934篇 |
2018年 | 1112篇 |
2017年 | 861篇 |
2016年 | 949篇 |
2015年 | 976篇 |
2014年 | 1383篇 |
2013年 | 1790篇 |
2012年 | 2830篇 |
2011年 | 2911篇 |
2010年 | 1572篇 |
2009年 | 1428篇 |
2008年 | 2442篇 |
2007年 | 2522篇 |
2006年 | 2263篇 |
2005年 | 2372篇 |
2004年 | 2105篇 |
2003年 | 1961篇 |
2002年 | 1848篇 |
2001年 | 253篇 |
2000年 | 145篇 |
1999年 | 301篇 |
1998年 | 396篇 |
1997年 | 324篇 |
1996年 | 240篇 |
1995年 | 241篇 |
1994年 | 192篇 |
1993年 | 179篇 |
1992年 | 125篇 |
1991年 | 120篇 |
1990年 | 100篇 |
1989年 | 104篇 |
1988年 | 88篇 |
1987年 | 77篇 |
1986年 | 71篇 |
1985年 | 55篇 |
1984年 | 77篇 |
1983年 | 62篇 |
1982年 | 66篇 |
1981年 | 72篇 |
1980年 | 66篇 |
1979年 | 37篇 |
1978年 | 36篇 |
1977年 | 43篇 |
1976年 | 29篇 |
1974年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Gregory C Gray Troy McCarthy Mark G Lebeck David P Schnurr Kevin L Russell Adriana E Kajon Marie L Landry Diane S Leland Gregory A Storch Christine C Ginocchio Christine C Robinson Gail J Demmler Michael A Saubolle Sue C Kehl Rangaraj Selvarangan Melissa B Miller James D Chappell Danielle M Zerr Deanna L Kiska Diane C Halstead Ana W Capuano Sharon F Setterquist Margaret L Chorazy Jeffrey D Dawson Dean D Erdman 《Clinical infectious diseases》2007,45(9):1120-1131
BACKGROUND: Recently, epidemiological and clinical data have revealed important changes with regard to clinical adenovirus infection, including alterations in antigenic presentation, geographical distribution, and virulence of the virus. METHODS: In an effort to better understand the epidemiology of clinical adenovirus infection in the United States, we adopted a new molecular adenovirus typing technique to study clinical adenovirus isolates collected from 22 medical facilities over a 25-month period during 2004-2006. A hexon gene sequence typing method was used to characterize 2237 clinical adenovirus-positive specimens, comparing their sequences with those of the 51 currently recognized prototype human adenovirus strains. In a blinded comparison, this method performed well and was much faster than the classic serologic typing method. RESULTS: Among civilians, the most prevalent adenovirus types were types 3 (prevalence, 34.6%), 2 (24.3%), 1 (17.7%), and 5 (5.3%). Among military trainees, the most prevalent types were types 4 (prevalence, 92.8%), 3 (2.6%), and 21 (2.4%). CONCLUSIONS: For both populations, we observed a statistically significant increasing trend of adenovirus type 21 detection over time. Among adenovirus isolates recovered from specimens from civilians, 50% were associated with hospitalization, 19.6% with a chronic disease condition, 11% with a bone marrow or solid organ transplantation, 7.4% with intensive care unit stay, and 4.2% with a cancer diagnosis. Multivariable risk factor modeling for adenovirus disease severity found that age <7 years (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4-7.4), chronic disease (OR, 3.6; 95% CI, 2.6-5.1), recent transplantation (OR, 2.7; 95% CI, 1.3-5.2), and adenovirus type 5 (OR, 2.7; 95% CI, 1.5-4.7) or type 21 infection (OR, 7.6; 95% CI, 2.6-22.3) increased the risk of severe disease. 相似文献
72.
73.
Christine Roberts Deborah Turnbull Les Irwig 《Australian and New Zealand journal of public health》1992,16(1):58-65
Abstract: The aim of this study was to determine changes in Sydney general practitioners' (GPs) knowledge about, attitude towards and intention to recommend screening mammography over the two years since a screening mammography program was first implemented in the Central Sydney Health Service (CSHS) area. 123 GPs from the CSHS area were selected from a list maintained by the Breast X-ray Programme, while 127 GPs from the rest of Sydney were selected from the Yellow Pages telephone directory. The overall response rate was 84 per cent. Outcomes were assessed by a self-administered questionnaire covering knowledge, attitudes and beliefs, self-report of recent referral practice, intention to recommend, and sources of information about mammography screening. Demographic data were also collected. Results showed that overall knowledge has increased both inside and outside the CSHS area, but important deficiencies in knowledge remain in both areas. Attitudes to screening mammography have improved in the CSHS area, especially regarding the efficacy of screening mammography and patient compliance. Importantly, positive views of screening mammography have declined outside the CSHS area, especially about whether screening mammography can save women's lives. GPs in both areas remain concerned about costs. The presence and strategies of the Breast X-ray Programme have had some positive effect on the attitudes of GPs towards, but not knowledge of, screening mammography. 相似文献
74.
Margaret J. Tango Evelyn Safaris Margarita Romanella Atousa Aminian Marina Katerelos Christine Somerwille RIek G. Tearle Martin J. Pearse Anthony J.E d'Apice 《Xenotransplantation》1997,4(1):25-33
Abstract: Transgenic expression of the human complement regulatory molecule CD59 in mice and genetic deletion of the major xenoantigen galactose α 1,3 galactose (Gal KO) each resulted in partial protection of spleen cells from lysis by human serum. These protective effects were additive when the two genetic modifications were combined. However, when the effects of these genetic modifications were examined in an ex vivo model in which mouse hearts were perfused with human plasma, it was Gal KO which was the modification which determined protection. CD59 expression alone was not protective and CD59 expression in combination with Gal knockout did not result in a significant additional increase in protection over and above that provided by Gal knockout alone. The likely explanation for this discrepancy between the in vitro and ex vivo data is that the H2-Kb promoter used to drive CD59 expression results I in substantially less expression on endothelium than on spleen cells. 相似文献
75.
76.
77.
A comparison of the stressors experienced by parents of intubated and non-intubated children 总被引:3,自引:0,他引:3
Caroline Haines BN RGN RSCN Christine Perger BHSc Sue Nagy RN BA FRCNA FCN 《Journal of advanced nursing》1995,21(2):350-355
When children are ill enough to require admission to paediatric intensive care, parents may become distressed about their child's medical condition and this distress may be compounded by the unfamiliar nature of the highly technological environment Parents of children who are sick enough to warrant intubation are particularly likely to be exposed to a frightening array of technological equipment Seventy-one parents of intubated and non-intubated children completed the Parental Stressor Scale Paediatnc Intensive Care Unit (PSS PICU) Overall the findings suggest that parents were most distressed (a) by the painful procedures to which their children were subjected, (b) by the sights and sounds of the intensive care unit and (c) by their children's reactions to intensive care The behaviour of staff towards parents and the way that staff communicated with them caused the least distress When the levels of stress reported by parents of intubated children were compared with those reported by parents of non-intubated children, different patterns of stress were found Painful procedures were a source of greater stress to parents of intubated children whereas the behaviour of staff and the children's reactions to the intensive care experience caused greater stress to the parents of the non-intubated children In general the findings suggest that the needs of parents of non-intubated children are being overlooked, with staff focusing more of their attention on the parents of intubated children 相似文献
78.
Helmut Seidel Barbara Harazin Kristina Pavlas Christine Sroka Jörg Richter Ralph Blüthner Udo Erdmann Jan Grzesik Barbara Hinz Reinhard Rothe 《International archives of occupational and environmental health》1988,61(1-2):95-106
Summary This study was carried out in order: (1) to examine the effects of isolated and combined prolonged exposures to noise and whole-body vibration on hearing, vision and subjectively experienced strain, and (2) to check the combined effects with repeated exposures. Six male subjects were exposed twice to noise (N) at 92 dBA, whole-body vibration (V) in the Z-axis at 4 Hz and 1.0 ms–2 rms, and noise and vibration (NV) for 90 min with each condition. Temporary threshold shifts of hearing (TTS) and their integrals (ITTS) were measured at 4, 6, 10, and 12 kHz. Visual acuity was examined by means of a very sensitive test. Cross-modality matching (CMM) of the handgrip force was used to judge the subjectively experienced strain. NV induced a clear tendency of higher TTS and ITTS than N, with several significant differences most pronounced at 10 kHz. With repeated exposures, the effect of NV decreased, while the reactions to N and V remained unchanged. The individual reactions to NV differed. The influence of the duration of exposures on vision depended on the condition; N caused time-dependent changes, whereas V did not. CMM-data increased with the duration of the exposure during V and NV. N was generally judged to be more straining than V; NV caused higher strain than V during the first 30 min of exposure only. Correlations between different effects suggest certain links between them. Additionally, less motivation — daily obtained by a questionnaire — often correlated with higher ITTS during N and NV. The results also illustrate the combined effects on the individual susceptibility, repetition of exposure, the kind of response, and, possibly, the actual psychic state.Abbreviations CMM
cross-modality matching
- MVC
maximum voluntary contraction force
- N
exposure condition: noise level 92dBA, no whole-body vibration
- NV
exposure condition: combined exposure to noise with a level of 92 dBA and wholebody vibration with 4 Hz, 1 ms–2 rms
- V
exposure condition: whole-body vibration with 4 Hz, 1 ms–2 rms
- TTS
temporary threshold shift
- ITTS
integral of temporary threshold shift
- WBV
whole-body vibration in the common sense
This work was done in the Temporary International Research Team on Combined Effects of Noise and Vibration of the Council of Mutual Economic Assistance of the Socialist Countries. The authors gratefully acknowledge the help and assistance of L.-M. Brumm, Y. Bening, M. Godau, G. Weber, and R. Vizcaino. 相似文献
79.
Cardiac MIBG scintigraphy is a sensitive tool for detecting cardiac sympathetic denervation in Parkinson's disease. 总被引:5,自引:0,他引:5
Frédéric Courbon Christine Brefel-Courbon Claire Thalamas Marie-Jeanne Alibelli Isabelle Berry Jean-Louis Montastruc Olivier Rascol Jean-Michel Senard 《Movement disorders》2003,18(8):890-897
[(123)I]Metaiodobenzylguanidine ([(123)I]MIBG) cardiac scintigraphy could be helpful to differentiate Parkinson's disease (PD) from multiple system atrophy (MSA), demonstrating that, in PD with autonomic failure but not in MSA, there is a myocardial postganglionic sympathetic dysfunction. To investigate whether this method is more sensitive than standard autonomic testing to detect early involvement of sympathetic cardiac efferent, we analyse MIBG myocardial uptake in 8 PD patients with normal autonomic testing (nondysautonomia PD group, NDPD) in comparison with 10 PD patients with abnormal autonomic testing (dysautonomia PD group, DPD) and 10 MSA patients. Global MIBG uptake was assessed using the ratio of [(123)I]MIBG uptake in the heart to the upper mediastinum (H/M) on planar scintigraphic data. Regional MIBG uptake was determined on two single photon emission tomography scans in regions of the left ventricle. The mean H/M ratios were significantly different among the three groups (P < 0.0001). H/M ratios of both NDPD and DPD patients groups (H/M = 1.83 +/- 0.50 and 1.24 +/- 0.40, respectively) were significantly lower than in MSA patients (H/M = 2.52 +/- 0.60). However, in NDPD patients, H/M was significantly higher than in DPD patients. When compared to MSA patients, NDPD patients showed a regional reduction in MIBG uptake in all left ventricle regions markedly in the apex and the inferior wall. Our results suggest that MIBG myocardial scintigraphy (analysis of both H/M ratio and regional MIBG uptake) may be more sensitive than standard autonomic testing for the early detection of silent autonomic dysfunction in PD. 相似文献
80.