全文获取类型
收费全文 | 371篇 |
免费 | 21篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 6篇 |
基础医学 | 21篇 |
口腔科学 | 2篇 |
临床医学 | 25篇 |
内科学 | 25篇 |
皮肤病学 | 1篇 |
神经病学 | 6篇 |
特种医学 | 21篇 |
外科学 | 14篇 |
综合类 | 12篇 |
预防医学 | 98篇 |
药学 | 23篇 |
肿瘤学 | 164篇 |
出版年
2021年 | 1篇 |
2020年 | 2篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 7篇 |
2013年 | 16篇 |
2012年 | 24篇 |
2011年 | 24篇 |
2010年 | 8篇 |
2009年 | 14篇 |
2008年 | 17篇 |
2007年 | 35篇 |
2006年 | 25篇 |
2005年 | 21篇 |
2004年 | 9篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 14篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 11篇 |
1995年 | 12篇 |
1994年 | 2篇 |
1993年 | 7篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有419条查询结果,搜索用时 0 毫秒
111.
This study examines whether the improvement in breast cancer survival in Hawaii suggested by an earlier analysis might be explained by concomitant temporal variations in prognostic factors. Characteristics at diagnosis and survival experience were compared for 1251 Caucasian, 1015 Japanese and 505 Hawaiian women diagnosed with invasive breast carcinoma during 1960-1979 and followed until the end of 1982. Time-trends were present for the patients' stage at diagnosis, age and socioeconomic status. A multivariate analysis using the Cox proportional hazards regression model revealed that adjustment for temporal variations in stage and age at diagnosis yielded a positive survival trend of a greater magnitude than that observed without adjustment, indicating that multivariate methods should be considered in time-trend analyses of cancer survival. Further analysis revealed that such improvement in breast cancer survival occurred for certain race-stage groups of patients only. Possible reasons for these trends in breast cancer prognostic factors and survival are discussed, along with potential biases. The data suggest that early detection might explain most of the survival improvement in Hawaii during the period of the study. 相似文献
112.
113.
迷迭香酸抗血栓和抗血小板聚集作用 总被引:40,自引:0,他引:40
迷迭香酸是丹参水溶性成分之一。大鼠体内实验(iv)表明,它能抑制静脉血栓形成。阻抑胶原诱导的血小板聚集,促进纤维蛋白溶解活性。当剂量为50及100 mg/kg时,血栓形成的抑制率分别为41.9和54.8%(P<0.vv05)。当剂量为100及150mg/kg时,血小板聚集的抑制率分别为30.4%(P<0.05)和46.4%(P<0.01),血浆优球蛋白溶解时间缩短(P<0.05)。纤维蛋白原含量无明显变化。以上结果说明,迷迭香酸有温和的抗血栓作用。其机理可能与抗血小板聚集和增强纤维蛋白溶解活性有关。 相似文献
114.
A girl aged 2.5 years with "covert toxocariasis" was treated with low-dose diethylcarbamazine because of supposed noticeable disseminated Toxocara canis infection without ocular or visceral manifestations. There was marked blood and bone marrow eosinophilia, significant increased Toxocara canis antibody (ELISA) and immunoglobulins E, G and M, leucocytosis and an increased sedimentation rate. She had no geophagia, but often sucked small stones, probably contaminated with faeces from puppies. Symptoms were fever, inactivity, weakness, tiredness and loss of appetite. She was followed clinically and with blood samples throughout a period of three years and four months. 相似文献
115.
Yumie Takata Gertraud Maskarinec Song-Yi Park Suzanne P Murphy Lynne R Wilkens Laurence N Kolonel 《European journal of cancer prevention》2007,16(5):409-414
We examined the association of breast cancer risk as assessed by mammographic density with dietary patterns in a case-control study nested within the Hawaii component of the multiethnic cohort. This analysis included 3512 prediagnostic mammograms from 1250 premenopausal and postmenopausal women. Mammographic density of the breast was quantified by a computer-assisted assessment method. All study participants completed a validated Food Frequency Questionnaire at entry into the multiethnic cohort. Factor analysis was performed to extract dietary patterns. We computed covariate-adjusted mean percentage densities by quartiles of factor scores using mixed models and weights to account for breast cancer prevalence in the population. Women in this study were primarily of Caucasian, Japanese or native Hawaiian ethnicity. The mean percentage density was 33%. The following three dietary patterns were identified: 'fat and meat', 'vegetables' and 'fruit and milk'. The differences in densities across quartiles of any patterns were relatively small and did not reach statistical significance. Women who had higher scores in the 'fat and meat' pattern had higher densities than those with lower scores (34.8 vs. 32.3%, P for trend=0.21). The 'vegetables' pattern and deep-yellow vegetable intake were weakly inversely associated with densities only among Japanese women (P for trend=0.13 and 0.03, respectively). Our findings indicated that meat and plant-based nutritional patterns are related to breast density. The influence of diet on mammographic densities, however, appears to be fairly small. Analyses of both dietary patterns and single dietary factors seem equally informative in examining dietary associations with percentage density. 相似文献
116.
Nomura AM Kolonel LN Miki K Stemmermann GN Wilkens LR Goodman MT Perez-Perez GI Blaser MJ 《The Journal of infectious diseases》2005,191(12):2075-2081
BACKGROUND: The objective was to investigate the association of Helicobacter pylori and serum pepsinogen (PG) levels with gastric adenocarcinoma. METHODS: Serum obtained from 299 patients at the time of cancer diagnosis and from 336 population-based control subjects was tested for PG I, PG II, and antibodies to H. pylori and to CagA. RESULTS: Subjects with low PG I levels or low PG I/II ratios were at increased risk for cardia and noncardia gastric cancer, whereas those with H. pylori or CagA seropositivity had an elevated risk for noncardia cancer only. Subjects seropositive for either H. pylori or CagA who had low PG I levels had the highest odds ratio (OR) (9.21 [95% confidence interval {CI}, 4.95-17.13]) for noncardia cancer, compared with subjects with neither factor. Elevated risks were also found among subjects with only 1 factor (OR, 5.40 [95% CI, 2.61-11.20] for low PG I level only; OR, 4.86 [95% CI, 5.90-8.13] for H. pylori or CagA seropositivity only). This pattern persisted when PG I/II ratio replaced PG I level and when CagA seropositivity alone replaced H. pylori immunoglobulin G or CagA seropositivity. CONCLUSIONS: The results suggest that persons with both H. pylori or CagA seropositivity and a low PG I level or PG I/II ratio are highly susceptible to development of noncardia gastric cancer. 相似文献
117.
Alana D Steffen Laurence N Kolonel Abraham M Nomura Faye S Nagamine Kristine R Monroe Lynne R Wilkens 《Cancer epidemiology, biomarkers & prevention》2008,17(2):447-454
BACKGROUND: The current study considers potential nonresponse bias and data quality issues in the Multiethnic Cohort, a prospective study of lifestyle-cancer associations among adults ages 45 to 75 years from five ethnic groups in Hawaii and California. METHODS: We examined determinants of early versus later response to the baseline questionnaire using logistic regression with response wave regressed on measures of demographics, history of illness, health behaviors, medication, and supplement use. RESULTS: Participants who were more health conscious tended to respond earlier. Female sex, more education, personal experience with cancer, more physical activity, and regular use of aspirin were associated with early response. Race other than white and current smoking were associated with later response. Of note, African-Americans and Latinos, with lower response rates, and Japanese, with the highest response rate overall, were more likely to respond to a later mailing. Results were generally consistent across sex, age groups (under 65, 65+), and ethnic groups and over time. Although repeated mailings increased the proportion responding and the diversity of participants, the percent of missing item responses increased somewhat with response wave. CONCLUSION: Multiple mailings are recommended for recruiting ethnic minority groups but the tradeoff may be more missing data among later respondents. 相似文献
118.
We used data collected on a retrospective cohort of 1,123 leprosy patients living in Hawaii between 1940 and 1970, to test the hypotheses that patients with lepromatous leprosy, who have an impairment in their cellular immune response, would have an increased risk for cancer and that patients with tuberculoid leprosy, who are immunologically competent, would have a normal or even a reduced cancer risk from beneficial stimulation of their cellular immune system by exposure to the Mycobacterium leprae organisms. Based on the survival analysis method, the results of the study supported the predicted increase in cancer cases among the lepromatous leprosy patients (19 observed, 12.7 expected; risk ratio = 1.5) and the predicted decrease among the tuberculoid leprosy patients (14 observed, 17.8 expected; risk ratio = 0.8); in both groups, the findings were consistent across the five racial categories of the study. However, none of these differences between observed and expected cases was statistically significant at the 5% level. The study provided no support for the alternate hypothesis that chronic antigenic stimulation by the M. leprae organisms might lead to an increase in tumors of the lymphoreticular system. 相似文献
119.
Dr. Abraham M. Y. Nomura MD Laurence N. Kolonel MD M. Ward Hinds MD 《Digestive diseases and sciences》1981,26(12):1116-1120
The incidence of colorectal adenocarcinoma increased in the five major ethnic groups in Hawaii, but more in men than women. The highest rates were in the Chinese and Japanese. The site-specific time trend patterns revealed that the greatest increase occurred in rectosigmoid cancer, followed by cancer of the sigmoid colon and the transverse descending colon. Rectal cancer had minimal changes in rates over time. The comparison of site-specific rates between the Japanese in Hawaii and Miyagi Prefecture, Japan, showed that the occurrence of cancer of the rectosigmoid, sigmoid, and transverse descending colon was far greater in Hawaii than Miyagi with minimal differences in the rates of rectal cancer. The findings from this study indicate that the separate anatomical locations of colorectal cancer probably have some distinct etiologies that need further investigation.Supported in part by grant I-NOI-CA-15655 and contract NOI-CP-53511 from the National Cancer Institute, National Institutes of Health. 相似文献
120.