全文获取类型
收费全文 | 1400篇 |
免费 | 154篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 82篇 |
妇产科学 | 27篇 |
基础医学 | 182篇 |
口腔科学 | 49篇 |
临床医学 | 182篇 |
内科学 | 277篇 |
皮肤病学 | 24篇 |
神经病学 | 72篇 |
特种医学 | 271篇 |
外科学 | 93篇 |
综合类 | 41篇 |
预防医学 | 113篇 |
眼科学 | 23篇 |
药学 | 82篇 |
肿瘤学 | 56篇 |
出版年
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 26篇 |
2017年 | 13篇 |
2016年 | 19篇 |
2015年 | 22篇 |
2014年 | 36篇 |
2013年 | 27篇 |
2012年 | 28篇 |
2011年 | 41篇 |
2010年 | 41篇 |
2009年 | 35篇 |
2008年 | 37篇 |
2007年 | 57篇 |
2006年 | 46篇 |
2005年 | 40篇 |
2004年 | 32篇 |
2003年 | 43篇 |
2002年 | 29篇 |
2001年 | 36篇 |
2000年 | 28篇 |
1999年 | 26篇 |
1998年 | 65篇 |
1997年 | 76篇 |
1996年 | 78篇 |
1995年 | 50篇 |
1994年 | 41篇 |
1993年 | 43篇 |
1992年 | 25篇 |
1991年 | 23篇 |
1990年 | 38篇 |
1989年 | 49篇 |
1988年 | 55篇 |
1987年 | 42篇 |
1986年 | 41篇 |
1985年 | 50篇 |
1984年 | 17篇 |
1983年 | 19篇 |
1982年 | 16篇 |
1981年 | 14篇 |
1980年 | 18篇 |
1979年 | 6篇 |
1978年 | 14篇 |
1977年 | 19篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1973年 | 6篇 |
1966年 | 5篇 |
1868年 | 4篇 |
排序方式: 共有1582条查询结果,搜索用时 10 毫秒
91.
92.
93.
94.
Words in melody: an H(2)15O PET study of brain activation during singing and speaking 总被引:1,自引:0,他引:1
We used H(2)15O PET to characterize the interaction of words and melody by comparing brain activity measured while subjects spoke or sang the words to a familiar song. Relative increases in activity during speaking vs singing were observed in the left hemisphere, in classical perisylvian language areas including the posterior superior temporal gyrus, supramarginal gyrus, and frontal operculum, as well as in Rolandic cortices and putamen. Relative increases in activity during singing were observed in the right hemisphere: these were maximal in the right anterior superior temporal gyrus and contiguous portions of the insula; relative increases associated with singing were also detected in the right anterior middle temporal gyrus and superior temporal sulcus, medial and dorsolateral prefrontal cortices, mesial temporal cortices and cerebellum, as well as in Rolandic cortices and nucleus accumbens. These results indicate that the production of words in song is associated with activation of regions within right hemisphere areas that are not mirror-image homologues of left hemisphere perisylvian language areas, and suggest that multiple neural networks may be involved in different aspects of singing. Right hemisphere mechanisms may support the fluency-evoking effects of singing in neurological disorders such as stuttering or aphasia. 相似文献
95.
Larcher VF Bourne J Aitken C Jeffries D Hodes D 《Archives of disease in childhood》2001,84(2):114-119
AIMS—To determine the effectiveness of a selective hospital based hepatitis B immunisation programme and the barriers to be overcome in obtaining a successful outcome.METHODS—Retrospective case note review of 265 infants born over a five year period to hepatitis B carrier mothers at a university affiliated hospital in Hackney, London.RESULTS—A total of 242 infants (91%) were fully vaccinated; 217 (82%) had serology; 31 required booster doses. Percentages failing to reach second, third vaccinations, and serology on schedule rose exponentially (7%, 18%, 33% respectively). Mobility was high (25%) and significantly affected outcome. A total of 95% Hackney resident babies were fully vaccinated compared with 78% non-residents. Uptake of routine immunisations was higher in Hackney residents than non-residents and greater in those who were eligible for hepatitis B vaccine. Name changes occurred in 35%. Translation requirements were high (85% for Turkish, Vietnamese, and Asian families). Requirements for specific postnatal counselling of mothers and hepatology referral fell significantly during the course of the study. Only seven of 22 babies born in 1995 in Tower Hamlets compared with 53 of 58 Hackney babies received a full vaccination course in non-hospital based primary care.CONCLUSION—In inner city areas with high prevalence of hepatitis B carriage, mobility, and diverse ethnicity, a dedicated centralised immunisation service can be highly effective, provided that adequate support services (translation, counselling, and parental referral) are available. 相似文献
96.
Sputum and plasma endothelin-1 levels in exacerbations of chronic obstructive pulmonary disease 总被引:13,自引:5,他引:8
Roland M Bhowmik A Sapsford RJ Seemungal TA Jeffries DJ Warner TD Wedzicha JA 《Thorax》2001,56(1):30-35
BACKGROUND: Endothelin (ET)-l is a bronchoconstrictor peptide produced in the airways. It has been implicated in the pathogenesis of asthma and virally mediated airway inflammation and may play a role in exacerbations of chronic obstructive pulmonary disease (COPD). METHODS: Seventy one patients with COPD were followed prospectively and sampled for plasma and sputum ET-1 levels when stable and during an exacerbation. Sputum was also examined for cytokines, human rhinovirus, and Chlamydia pneumoniae. RESULTS: Plasma ET-1 levels were available for 67 patients with stable COPD (mean (SD) 0.58 (0.31) pg/ml); 28 pairs of stable-exacerbation plasma samples had a mean stable ET-1 level of 0.54 (0.30) pg/ml rising to 0.67 (0.35) pg/ml at exacerbation (mean difference 0.13, 95% confidence interval (CI) 0.04 to 0.21, p = 0.004). Plasma ET-1 levels in the 67 patients with stable COPD were inversely correlated with baseline forced expiratory volume in one second (FEV(1); r = -0. 29, p = 0.022) and forced vital capacity (FVC; r = -0.38, p = 0.002). The change in plasma ET-1 levels during an exacerbation correlated with the change in oxygen saturation (SaO(2); r = -0.41, p = 0.036). In 14 stable-exacerbation pairs of sputum samples median stable ET-1 levels were 5.37 (0.97-21.95) pg/ml rising to 34.68 (13.77-51.95) pg/ml during an exacerbation (mean difference 25.14, 95% CI 3.77 to 46.51, p = 0.028). This increase in sputum ET-1 levels correlated with the increase in plasma ET-1 levels (r = 0.917, p = 0.001) and sputum interleukin (IL)-6 levels (r = 0.718, p = 0.013). CONCLUSIONS: Sputum levels of ET-1 rise in COPD patients during an exacerbation and this is reflected by a smaller rise in plasma ET-1 levels. ET-1 may have a role in mediating airway inflammatory changes during exacerbations of COPD. 相似文献
97.
Morgen K Jeffries NO Stone R Martin R Richert ND Frank JA McFarland HF 《Multiple sclerosis (Houndmills, Basingstoke, England)》2001,7(3):167-171
Correlations between conventional MRI measures of disease activity and clinical disability in multiple sclerosis (MS) have been disappointing. Because ring-enhancing lesions may reflect a more destructive pathology, we tested their potential association with disease severity. We evaluated active lesions with regard to their enhancement pattern on serial magnetic resonance images in a cohort of 28 patients with relapsing-remitting MS. The percentage of ring-enhancing lesions correlated with EDSS, T2 lesion load and duration of disease and predicted the occurrence of relapses during the baseline period of observation as well as after 3 years of follow-up in multiple logistic regression analysis. The findings suggest that the pathological process reflected by ring-enhancing lesions may contribute to more severe clinical disease. 相似文献
98.
Oscillatory motion of the normal cervical spinal cord 总被引:2,自引:0,他引:2
99.
Ashley C. Lima Karen Hilyard Teaniese Latham Davis Kathleen de Marrais William L. Jeffries IV Jessica Legge Muilenburg 《Culture, health & sexuality》2018,20(4):442-457
In the USA, partner non-monogamy is reported to be more common among African American women than White women and may contribute to African American women’s increased risk for HIV and other sexually transmitted infections (STIs). Few studies have explicitly and comprehensively described the protective behaviours that African American women employ with non-monogamous partners to reduce their HIV risk. We conducted interviews to examine protective behaviours among 11 African American women aged 18–24 years who perceived that a partner in the preceding 12 months had another sex partner. Participants described three types of partnerships with 29 non-monogamous men; these partnerships clustered into three categories. Narrative analysis revealed an overall paucity of protective behaviours with non-monogamous partners. Protective behaviours (i.e. communication and condom use) were informed by partnership type, rather than perceptions of non-monogamy. There were few instances in which partner non-monogamy motivated women to terminate sex partnerships. Rather, these decisions were often motivated by changes in other relationship dynamics. To address HIV/STI risk related to partner non-monogamy, HIV prevention strategies for young African American women should emphasise the importance of condom use in all non-marital partnership types. Interventions where testing is available may be effective for women who frequently test for HIV/STIs but do not use condoms. 相似文献
100.
Coralline hydroxyapatite bone graft substitutes: preliminary report of radiographic evaluation 总被引:1,自引:0,他引:1
A new bone graft substitute made by conversion of the calcium carbonate exoskeleton of reef-building sea coral into hydroxyapatite has recently become clinically available. The normal radiographic appearance of two forms of this material is described. In the immediate postoperative period, the exoskeletal architecture of these implants is readily appreciated. With graft incorporation over the ensuing months, their intrinsic structure is gradually lost in association with poor marginal definition. Evolving radiographic findings reflect the biocompatible nature of these implants, which provides the potential for ingrowth of native bone with preservation of the coralline scaffold, resulting in enhanced biomechanical properties. 相似文献