全文获取类型
收费全文 | 963篇 |
免费 | 42篇 |
国内免费 | 22篇 |
专业分类
儿科学 | 33篇 |
妇产科学 | 15篇 |
基础医学 | 79篇 |
口腔科学 | 21篇 |
临床医学 | 84篇 |
内科学 | 252篇 |
皮肤病学 | 24篇 |
神经病学 | 11篇 |
特种医学 | 193篇 |
外科学 | 55篇 |
综合类 | 9篇 |
预防医学 | 110篇 |
眼科学 | 8篇 |
药学 | 85篇 |
肿瘤学 | 48篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 12篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 11篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 20篇 |
2012年 | 23篇 |
2011年 | 35篇 |
2010年 | 25篇 |
2009年 | 22篇 |
2008年 | 46篇 |
2007年 | 46篇 |
2006年 | 45篇 |
2005年 | 42篇 |
2004年 | 33篇 |
2003年 | 42篇 |
2002年 | 28篇 |
2001年 | 36篇 |
2000年 | 19篇 |
1999年 | 23篇 |
1998年 | 34篇 |
1997年 | 44篇 |
1996年 | 27篇 |
1995年 | 28篇 |
1994年 | 22篇 |
1993年 | 13篇 |
1992年 | 17篇 |
1991年 | 22篇 |
1990年 | 17篇 |
1989年 | 30篇 |
1988年 | 35篇 |
1987年 | 25篇 |
1986年 | 20篇 |
1985年 | 24篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 19篇 |
1981年 | 8篇 |
1980年 | 15篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 14篇 |
1975年 | 5篇 |
1971年 | 2篇 |
排序方式: 共有1027条查询结果,搜索用时 15 毫秒
991.
Lai S Chen J Celentano D Page JB Lai H Yang J Liu W McCoy CB Yu XF 《Journal of psychoactive drugs》2000,32(3):285-292
This preliminary study collected data from 326 heroin users in Guangxi Province, China, in 1997. Logistic regression analysis was performed to identify the risk factors for injection. Survival analysis identified factors independently associated with time from initiation of heroin use to adoption of injection. Four factors were independently associated with injection: number of friends who used heroin in the last year, duration of heroin use, dose of heroin consumed, and total number of times detoxified in drug treatment and rehabilitation centers. Only gender and duration of heroin use were independently associated with time to first injection. Median time to first injection was 11 months for males and 22 months for females. Median time to first injection varied by age. Median time to injection for those who used heroin for more than one year was 8.1 months; it was 19.1 months for on to five years of use, and 40.5 months for more than five years of use. This study's preliminary findings suggest that younger, more recent heroin users, and males are at increased risk of becoming injectors, a major risk behavior for HIV acquisition. 相似文献
992.
Luongo V Pirozzi G Caracò C Errico S de Angelis F Celentano E Paino F Chiofalo MG Luongo M Mozzillo N Lombardi ML 《Tissue antigens》2004,64(1):84-87
The current study focuses the analysis on the possible relationship between HLA allele frequency and clinical outcome of melanoma in a population of 382 Italian patients, as compared with 203 ethnically matched controls. In a 3-year follow-up study, results showed significant differences between groups of patients selected according to clinical stage, histology, and progression of the disease. A*01 seems to be correlated with a less aggressive variant of the disease, whereas DRB1*01-DQB1*0501 seems to be associated with metastatic progression of melanoma. Moreover, a negative association with B*13, B*44, as well as with DRB1*04-DQB1*0302 was found. A multivariate logistic regression model showed HLA-DRB1*04 to behave as an independent favorable prognostic marker of melanoma in our population (OR = 2.34, CI = 1.15-4.74). 相似文献
993.
Gray RH; Simpson JL; Bitto AC; Queenan JT; Li C; Kambic RT; Perez A; Mena P; Barbato M; Stevenson W; Jennings V 《Human reproduction (Oxford, England)》1998,13(5):1397-1400
This was a multicentred, prospective study of pregnancies among women using
natural family planning. The women maintained natural family planning
charts of the conception cycle, recording acts of intercourse and signs of
ovulation (cervical mucus changes, including peak day and basal body
temperature). Charts were used to assess the most probable day of
insemination relative to the day of ovulation and length of the follicular
phase of the cycle. The sex ratio (males per 100 females) for 947 singleton
births was 101.5, not significantly different from the expected value of
105. The sex ratio did not vary consistently or significantly with the
estimated timing of insemination relative to the day of ovulation, with the
estimated length of the follicular phase or with the planned or unplanned
status of the pregnancy. Although these findings may be affected by
imprecision of the data, the study suggests that manipulation of the timing
of insemination during the cycle cannot be used to affect the sex of
offspring.
相似文献
994.
Identification of a hot spot for microdeletions in patients with X- linked deafness type 3 (DFN3) 900 kb proximal to the DFN3 gene POU3F4 总被引:5,自引:1,他引:5
995.
996.
Harawa NT Greenland S Bingham TA Johnson DF Cochran SD Cunningham WE Celentano DD Koblin BA LaLota M MacKellar DA McFarland W Shehan D Stoyanoff S Thiede H Torian L Valleroy LA 《Journal of acquired immune deficiency syndromes (1999)》2004,35(5):526-536
Using data from a multisite venue-based survey of male subjects aged 15 to 22 years, we examined racial/ethnic differences in demographics, partner type, partner type-specific condom use, drug use, and HIV prevalence in 3316 US black, multiethnic black, Latino, and white men who have sex with men (MSM). We further estimated associations of these factors with HIV infection and their influence on racial/ethnic disparities in HIV prevalence. HIV prevalences were 16% for both black and multiethnic black participants, 6.9% for Latinos, and 3.3% for whites. Paradoxically, potentially risky sex and drug-using behaviors were generally reported most frequently by whites and least frequently by blacks. In a multiple logistic regression analysis, positive associations with HIV included older age, being out of school or work, sex while on crack cocaine, and anal sex with another male regardless of reported condom use level. Differences in these factors did not explain the racial/ethnic disparities in HIV prevalence, with both groups of blacks experiencing more than 9 times and Latinos experiencing approximately twice the fully adjusted odds of infection compared with whites. Understanding racial/ethnic disparities in HIV risk requires information beyond the traditional risk behavior and partnership type distinctions. Prevention programs should address risks in steady partnerships, target young men before sexual initiation with male partners, and tailor interventions to men of color and of lower socioeconomic status. 相似文献
997.
HIV/AIDS Stigma: Reliability and Validity of a New Measurement Instrument in Chennai, India 总被引:1,自引:0,他引:1
Zelaya CE Sivaram S Johnson SC Srikrishnan AK Solomon S Celentano DD 《AIDS and behavior》2008,12(5):781-788
HIV/AIDS stigma is a frequently cited barrier to HIV prevention, including voluntary counseling and testing. A reliable and valid measurement instrument is critical to empirically assess the extent and effects of HIV/AIDS stigma. The paper reports the development and psychometric testing of an HIV/AIDS stigma scale among 200 men in India. The resulting 24-item scale and the four subscales had good internal consistency (Cronbach's alpha overall was 0.81; subscales were 0.86, 0.73, 0.72 and 0.76, respectively). The scale and distinct subscales suggest a valid and reliable measure for HIV/AIDS stigma in a setting with highly prevalent HIV risk behaviors. 相似文献
998.
Farinaro E Stranges S Guglielmucci G Iermano P Celentano E Cajafa A Trevisan M 《Nutrition, metabolism, and cardiovascular diseases : NMCD》1999,9(4):196-202
BACKGROUND AND AIM: The predictive role of heart rate as a new, independent risk factor for the development of high blood pressure and cardiovascular diseases (CVD) has been investigated in recent years and many studies have demonstrated a significant and independent association between heart rate, blood pressure and cardiovascular (CV) endpoints. Various pathogenic pathways can be postulated to explain this association and the role of heart rate as a plausible risk factor. Previous studies have been limited to the examination of small samples of general populations. By contrast, our study is based on a large cohort (38,145) of hypertensive patients. METHODS AND RESULTS: The Italian TensioPulse Study is a detailed investigation of the relation between heart rate (HR) and other CV risk factors in a large cohort of hypertensives. A strong, positive relationship was found between heart rate and both systolic and diastolic blood pressure: r = 0.21 for SBP in both sexes, and r = 0.21 and r = 0.24 for DBP in men and women respectively. Smoking and drinking habits seem to be associated with higher heart rate, SBP and DBP values. CONCLUSIONS: These findings and the observation that more than one out of three hypertensives had a relatively high heart rate could assist in the organisation of prevention programmes. Correction of certain lifestyle factors must precede the decision to use drugs to reduce the global CVD risk. 相似文献
999.
Jessica F. Magidson Xin Li Matthew J. Mimiaga Ayana T. Moore Kriengkrai Srithanaviboonchai Ruth Khalili Friedman Mohammad Limbada James P. Hughes Vanessa Cummings Charlotte A. Gaydos Vanessa Elharrar David Celentano Kenneth H. Mayer Steven A. Safren 《AIDS and behavior》2016,20(4):699-709
Successful biomedical prevention/treatment-as-prevention (TasP) requires identifying individuals at greatest risk for transmitting HIV, including those with antiretroviral therapy (ART) nonadherence and/or ‘amplified HIV transmission risk,’ defined as condomless sex with HIV-uninfected/unknown-status partners when infectious (i.e., with detectable viremia or STI diagnosis according to Swiss criteria for infectiousness). This study recruited sexually-active, HIV-infected patients in Brazil, Thailand, and Zambia to examine correlates of ART nonadherence and ‘amplified HIV transmission risk’. Lower alcohol use (OR = .71, p < .01) and higher health-related quality of life (OR = 1.10, p < .01) were associated with greater odds of ART adherence over and above region. Of those with viral load data available (in Brazil and Thailand only), 40 % met Swiss criteria for infectiousness, and 29 % had ‘amplified HIV transmission risk.’ MSM had almost three-fold (OR = 2.89, p < .001) increased odds of ‘amplified HIV transmission risk’ (vs. heterosexual men) over and above region. TasP efforts should consider psychosocial and contextual needs, particularly among MSM with detectable viremia. 相似文献
1000.
M Santomauro A Cuocolo L Celentano S Ferraro L Pace C Pappone G Maddalena M Salvatore M Chiariello 《Angiology》1992,43(10):818-825
Recently the use of a new radioactive agent with physical and biological properties more favorable than those of thallium 201, methoxy-isobutyl-isonitrile (MIBI) labeled with technetium 99m (Tc 99m), has permitted simultaneous performance of perfusion and function studies in ischemic cardiopathy. Transesophageal atrial pacing (TAP) technique has evolved as an alternative provocative test of ischemia. The authors compared the capability of Tc 99m-MIBI myocardial scintigraphy, combined with TAP, with that of Tc 99m-MIBI, combined with maximal stress test, in the diagnosis of ischemic cardiopathy. They studied 11 patients with a clinical history of angina pectoris. Myocardial scintigraphy was performed at rest, after stress test, and after TAP. Finally, all the patients underwent coronary angiography. The analysis of myocardial perfusion images on both Tc 99m-MIBI associated with TAP and with stress demonstrated, in 165 myocardial segments examined: 143 normal, 20 reversible defects, 2 irreversible defects. The concordance of localization between coronarographic data and scintigraphic reversible and irreversible defects was 85%. In conclusion TAP proves to be a valid and sensitive provocative test of ischemia when combined with myocardial scintigraphy and with Tc 99m-MIBI. 相似文献