首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   978篇
  免费   76篇
  国内免费   3篇
耳鼻咽喉   4篇
儿科学   59篇
妇产科学   18篇
基础医学   159篇
口腔科学   11篇
临床医学   109篇
内科学   164篇
皮肤病学   49篇
神经病学   148篇
特种医学   24篇
外科学   73篇
综合类   5篇
一般理论   2篇
预防医学   120篇
眼科学   5篇
药学   66篇
肿瘤学   41篇
  2024年   3篇
  2023年   5篇
  2022年   8篇
  2021年   8篇
  2020年   9篇
  2019年   17篇
  2018年   28篇
  2017年   15篇
  2016年   15篇
  2015年   26篇
  2014年   31篇
  2013年   48篇
  2012年   57篇
  2011年   68篇
  2010年   46篇
  2009年   36篇
  2008年   66篇
  2007年   52篇
  2006年   62篇
  2005年   51篇
  2004年   57篇
  2003年   56篇
  2002年   46篇
  2001年   17篇
  2000年   18篇
  1999年   19篇
  1998年   7篇
  1997年   10篇
  1996年   8篇
  1995年   7篇
  1993年   6篇
  1992年   13篇
  1991年   9篇
  1990年   13篇
  1989年   15篇
  1988年   10篇
  1987年   6篇
  1986年   5篇
  1985年   10篇
  1984年   5篇
  1983年   3篇
  1982年   5篇
  1980年   4篇
  1979年   5篇
  1978年   5篇
  1976年   9篇
  1975年   6篇
  1974年   3篇
  1972年   5篇
  1967年   3篇
排序方式: 共有1057条查询结果,搜索用时 31 毫秒
1.
2.
Sixteen cohorts of men aged 40–59 years at entry were examined with the measurement of some risk factors and then followed-up for mortality and causes of death for 25 years. These cohorts were located in the USA (1 cohort), Finland (2), the Netherlands (1), Italy (3), the former Yugoslavia (5), Greece (2), and Japan (2), and included a total of 12,763 subjects.Large differences in age-adjusted coronary heart disease (CHD) death rates were found, with extremes of 45 per 1000 in 25 years in Tanushimaru, Japan, to 288 per 1000 in 25 years in East Finland. In general, higher rates were found in the US and Northern European cohorts as compared to the Southern European and Japanese cohorts. However, during the last 10 years of follow-up large increases of CHD death rates were found in some Yugoslavian areas. Out of 5 measured entry characteristics treated as age-adjusted levels (serum cholesterol, systolic blood pressure, cigarette smoking, body mass index and physical activity at work), only serum cholesterol was significant in explaining cohort differences in CHD death rates.Over 50% of the variance in CHD death rates in 25 years was accounted for by the difference in mean serum cholesterol. This association tended to decline with increasing length of follow-up, but this was due to the great changes in mean serum cholesterol in the two Jugoslavian cohorts of Velika Krsna and Zrenjanin. When these two cohorts were excluded the association increased with time.Changes in mean serum cholesterol between year 0 and 10 helped in explaining differences in CHD death rates from year 10 onward.It can be concluded that this study suggests that mean serum cholesterol is the major risk factor in explaining cross-cultural differences in CHD.  相似文献   
3.
BACKGROUND: Alternaria alternata and Cladosporium herbarum are common fungi in outdoor environments, but their clinical significance has not been elucidated in Finland. OBJECTIVE: To evaluate the prevalence of IgE-mediated allergy and clinical outcomes caused by sensitization to fungal allergens in patients with suspected allergy. METHODS: Skin prick tests (SPTs) were performed with C. herbarum in 6,376 patients and also with A. alternata in 1,504 of these patients. SPTs were repeated in 40 patients who showed a positive reaction to either allergen using commercial and in-house extracts. The association of SPT with allergen-specific IgE antibodies in serum was evaluated. Seven patients also underwent a conjunctival challenge test with these fungal allergens. RESULTS: The prevalence of positive SPT results to A. alternata and C. herbarum was low (2.8% and 2.7%, respectively). Among the 40 patients, atopic eczema/dermatitis syndrome was found in 58%, asthma in 44%, and rhinitis in 31%. Most of the patients displayed SPT reactions also to several other fungal allergens, and 75% to 80% showed a positive SPT reaction to allergens of pet animals or pollens. Four patients had a positive reaction to A. alternata and 6 to C. herbarum in the conjunctival challenge test. CONCLUSION: In the Finnish population with allergic symptoms, IgE-mediated sensitization to 2 common fungal allergens was rare and of minor clinical importance. SPT reactions to fungi are mostly observed in patients with multiple sensitivity to various allergens.  相似文献   
4.
Addictive drugs, including ethanol, increase the brain's dopaminergic transmission, and catechol-o-methyltransferase (COMT) enzyme has a crucial role in dopamine inactivation. A common functional polymorphism in the COMT gene results in a three- to four-fold variation in enzyme activity. In a previous study, we found an association between type 1 (with late-onset but without prominent antisocial behavior) alcoholism and the low activity allele of the COMT gene. In this work we analyzed whether the COMT polymorphism has any effect on the development of type 2 (with early-onset and habitual impulsive violent behavior) alcoholism. The COMT genotype was determined in 62 impulsive violent recidivist offenders with early-onset (type 2) alcoholism, 123 late-onset nonviolent (type 1) alcoholics, and 267 race and gender-matched controls. The allele and genotype frequencies of these groups were compared with each other and also with previously published data from 3,140 Finnish blood donors. The type 2 alcoholics did not differ from either the blood donors or the controls. The low activity (L) allele frequency was higher among type 1 alcoholics (chi(2) = 4.98, P = 0.026) when compared with type 2 cases. The odds ratio for type 1 alcoholism as compared with type 2 alcoholism for those subjects with the LL genotype versus the HH genotype was 3.0 (95% confidence interval 1.1-8.4, P = 0.017). The results suggest that COMT genotype has no major role in the development of early-onset alcoholism with severe antisocial behavior.  相似文献   
5.
6.
The failure to identify biomarkers of clinical significance for cancer diagnosis and prognosis generated a great deal of skepticism in regard to the usefulness of autoantibody-based methods. SEREX was a major advancement in immunoscreening that resulted in the identification of a large group of autoantigens recognized by cancer sera. However, few SEREX-defined autoantigens have proven to have definitive diagnostic value in clinical practice. Often, the identified antigens are patient-specific rather than tumor-specific and many tumor-associated antigens are rare in expression libraries made from non-autologous cells. Since autoantibodies are part of the normal immune response, it can be difficult to single out tumor-associated antibodies from the scores of irrelevant patient-specific responses. In our view, any practical approach for identifying cancer-related autoantigens must include an integral strategy for demonstrating tumor relevance early in the screening process. Care must also be taken not to exclude potentially important autoantibodies by pre-screening manipulations to patient sera. We have introduced substantial modifications in SEREX, designed to minimize confounding effects of unrelated autoantibodies and to eliminate steps that preclude the identification of cancer-related autoantigens commonly recognized by cancer sera. In addition, we incorporate methodology to identify candidate antigens that have potential diagnostic or prognostic value prior to their molecular cloning and characterization.  相似文献   
7.
The aim of the present study was to investigate cross-sectionally the association of postmenopausal muscle strength with simple performance tests. A random sample of 1,166 naturally postmenopausal women (born 1932–1941) was selected from the Kuopio Osteoporosis Risk Factor and Prevention (OSTPRE) study cohort. Grip and quadriceps strength were measured with strain gauge dynamometers and reported in both absolute values (KPa and kg) and per kilogram of body mass (N cm–2 kg–1 and N kg–1). In addition, two performance tests, ability to stand on one foot and ability to squat down to touch the floor were carried out. A five-category self-assessment of overall health (very good, good, moderate, bad, and very bad) was obtained by postal questionnaire. The women that were able to stand on one foot and able to squat down to touch the floor had greater grip and quadriceps strength than their counterparts (P<0.001 and P<0.03 in ANOVA, respectively). In addition, self-assessed health had a strong positive association with muscle strength in the grip and leg extensor muscles in ANOVA (P<0.001 between very good and moderate or poorer state of health) and regression model (P<0.001). Adjustment for age, duration of menopause, body mass, height, physical activity level, use of HRT, and number of diseases and medications did not change any of the main effects. Also, there were no differences in results between absolute measurement values and values reported per kilogram of body mass. According to the present study, a simple performance test may be useful in the prediction of postmenopausal muscle strength. Furthermore, self-assessed state of health is strongly associated with muscle strength in postmenopausal women.  相似文献   
8.
9.
Journal of Immigrant and Minority Health - Parental support is of paramount importance in the promotion of positive parenting, strengthening parenthood and protecting children from disadvantages...  相似文献   
10.
Recently, we demonstrated that radiolabelled interleukin-l (IL-1) specifically accumulates in focal infection in mice through interaction with its receptor. Unfortunately, systemic side-effects of IL-1 limit its clinical application. We investigated whether this problem could be circumvented by using the interleukin-1 receptor antagonist (IL-Ira), an equally sized protein that binds to the same receptors as IL-1 without induction of biological effects. Biodistribution of125I-IL-1 and125I-IL-Ira was determined in Swiss mice withStaphylococcus aureus-induced abscesses in the left calf muscle at 4, 12, 24 and 48 h after injection of either 0.4 MBq125I-IL1 or 0.4 MBq125I-IL-Ira. In vitro, the proteins displayed similar binding characteristics. High-performance liquid chromatographic analysis revealed a tendency for IL-Ira to associate with serum proteins. Both proteins rapidly cleared from most organs. However, the abscess uptake of125I-IL-Ira was significantly lower than that of125I-IL-1 at all time points (48 h p.i.: 0.06±0.01%ID/g vs 0.60±0.04%ID/g;P<0.02). The abscess-to-contralateral muscle ratios did not exceed 15.5±2.9 for125I-IL-lra, while the ratios for125I-IL-1 reached 46.9±5.7 at 48 h p.i. Despite similar in vitro receptor binding, the abscess uptake of IL-Ira was much lower than that of IL-1. The interaction of IL-Ira with serum proteins in vivo may reduce its availability for receptor binding in the infection. Although on theoretical grounds IL-Ira is very interesting, these characteristics will prevent its development as a clinically useful radiopharmaceutical to image infection.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号