全文获取类型
收费全文 | 780篇 |
免费 | 55篇 |
专业分类
儿科学 | 44篇 |
妇产科学 | 7篇 |
基础医学 | 84篇 |
口腔科学 | 14篇 |
临床医学 | 90篇 |
内科学 | 189篇 |
皮肤病学 | 60篇 |
神经病学 | 14篇 |
特种医学 | 140篇 |
外科学 | 67篇 |
综合类 | 16篇 |
预防医学 | 34篇 |
眼科学 | 12篇 |
药学 | 30篇 |
肿瘤学 | 34篇 |
出版年
2022年 | 14篇 |
2021年 | 23篇 |
2019年 | 9篇 |
2018年 | 18篇 |
2017年 | 10篇 |
2016年 | 13篇 |
2015年 | 19篇 |
2014年 | 17篇 |
2013年 | 43篇 |
2012年 | 19篇 |
2011年 | 22篇 |
2010年 | 32篇 |
2009年 | 30篇 |
2008年 | 14篇 |
2007年 | 12篇 |
2006年 | 19篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 12篇 |
2001年 | 18篇 |
2000年 | 11篇 |
1999年 | 15篇 |
1998年 | 32篇 |
1997年 | 30篇 |
1996年 | 32篇 |
1995年 | 27篇 |
1994年 | 28篇 |
1993年 | 23篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 5篇 |
1989年 | 23篇 |
1988年 | 17篇 |
1987年 | 20篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1975年 | 11篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1971年 | 9篇 |
1968年 | 5篇 |
排序方式: 共有835条查询结果,搜索用时 0 毫秒
21.
22.
23.
Total radical trapping antioxidant potential (TRAP) and exercise 总被引:1,自引:0,他引:1
Sharpe PC; Duly EB; MacAuley D; McCrum EE; Mulholland C; Stott G; Boreham CA; Kennedy G; Evans AE; Trinick TR 《QJM : monthly journal of the Association of Physicians》1996,89(3):223-228
The relationship between physical activity, physical fitness and total
radical trapping antioxidant potential (TRAP) was examined in the Northern
Ireland Health and Activity Survey. This was a cross-sectional population
study (n = 1600) using a two-stage probability sample of the population.
TRAP was calculated using the sum of the individual serum antioxidant
concentrations (urate, protein thiols, ascorbate, alpha tocopherol and
bilirubin) multiplied by their respective stoichiometric values. Physical
fitness was determined by estimation of VO2max by extrapolation from
submaximal oxygen uptake, and physical activity was recorded by
computer-assisted interview. Mean serum TRAP concentrations were
significantly higher in males (653 +/- 8.2 mumol/l, mean +/- SEM) compared
to females (564 +/- 8.0 mumol/l) (p < 0.0001). Both male and female
smokers had significantly lower TRAP values than non-smokers (males p <
0.0001, females p = 0.02). In females, there was a positive relationship of
TRAP with age (p < 0.001) and body mass index (p < 0.001) but a
negative relationship with physical fitness (p < 0.05). The known
beneficial effects of exercise and activity do not appear to be directly
mediated through increased antioxidant status.
相似文献
24.
JJ Korelitz ; AE Williams ; MP Busch ; TF Zuck ; HE Ownby ; LJ Matijas ; DJ Wright 《Transfusion》1994,34(10):870-876
BACKGROUND: Most blood centers utilize a confidential unit exclusion (CUE) process, intended to reduce the risk of transfusion-associated infectious diseases by allowing high-risk donors confidentially to exclude their blood from use for transfusion. The effectiveness of this method remains controversial. STUDY DESIGN AND METHODS: Confirmatory or supplemental test results for antibodies to human immunodeficiency virus, human T-lymphotropic virus type I, and hepatitis C virus, as well as hepatitis B surface antigen and syphilis and screening test results for antibodies to hepatitis B core (antigen) and alanine aminotransferase levels were obtained for approximately 1.8 million units donated during 1991 and 1992 at five blood centers within the United States. The prevalences of these infectious disease markers in units that the donors confidentially excluded (CUE+) and units that the donors did not exclude (CUE-) were calculated and examined within demographic subgroups. RESULTS: Units that were CUE+ were 8 to 41 times more likely to be seropositive for antibodies to human immunodeficiency virus and hepatitis C virus, hepatitis B surface antigen, and syphilis and three to four times more likely to react for antibody to hepatitis B core (antigen) or to have elevated alanine aminotransferase levels than units that were CUE- (p < 0.001). The positive predictive value of CUE (the percentage of CUE+ units that were confirmed seropositive for any marker) was 3.5 percent, and the sensitivity of CUE (the percentage of confirmed-seropositive units that were CUE+) was 2.3 percent. CONCLUSION: The current CUE process has low sensitivity and apparently low positive predictive value, and in many cases, it appeared that donors misunderstood it. Yet, CUE was not a “random process,” as CUE+ units were more likely to be seropositive for any infectious disease marker than CUE- units. This suggests that efforts to improve the CUE system may be warranted. As risk factors for transfusion-transmitted infection become more difficult to identify by history-based screening, however, such efforts may have limited effect. 相似文献
25.
Christine AE Schutgens Merel Schuring Toon AJ Voorham Alex Burdorf 《BMC public health》2009,9(1):197-11
Background
The relationship between poor health and unemployment is well established. Health promotion among unemployed persons may improve their health. The aims of this study were to investigate characteristics of non-participants and drop-outs in a multidisciplinary health promotion programme for long-term unemployed persons with health complaints, to evaluate changes in physical health among participants, and to investigate determinants of improvement in physical health. 相似文献26.
27.
R Mitchell Baldwin Gordon M Barrett Doris AE Parolin Jana K Gillies Judith A Paget Sylvie J Lavictoire Douglas A Gray Ian AJ Lorimer 《Molecular cancer》2010,9(1):233
Background
Glioblastoma is one of the deadliest forms of cancer, in part because of its highly invasive nature. The tumor suppressor PTEN is frequently mutated in glioblastoma and is known to contribute to the invasive phenotype. However the downstream events that promote invasion are not fully understood. PTEN loss leads to activation of the atypical protein kinase C, PKCι. We have previously shown that PKCι is required for glioblastoma cell invasion, primarily by enhancing cell motility. Here we have used time-lapse videomicroscopy to more precisely define the role of PKCι in glioblastoma. 相似文献28.
29.
Eight‐Year Retention Rate of First‐Line Tumor Necrosis Factor Inhibitors in Spondyloarthritis: A Multicenter Retrospective Analysis 下载免费PDF全文
30.
Decellularized biological matrices: an interesting approach for cardiovascular tissue repair and regeneration 下载免费PDF全文
Francesca Boccafoschi Margherita Botta Luca Fusaro Francesco Copes Martina Ramella Mario Cannas 《Journal of tissue engineering and regenerative medicine》2017,11(5):1648-1657
The repair and replacement of blood vessels is one of the most challenging topics for biomedical research. Autologous vessels are preferred as graft materials, but they still have many issues to overcome: for instance, they need multiple surgical procedures and often patients may not have healthy and surgically valuable arteries useful as an autograft. A tissue‐engineering approach is widely desirable to generate biological vascular prostheses. Recently, decellularization of native tissue has gained significant attention in the biomedical research field. This method is used to obtain biological scaffolds that are expected to maintain the complex three‐dimensional structure of the extracellular matrix, preserving the biomechanical properties of the native tissues. The decellularizing methods and the biomechanical characteristics of these products are presented in this review. Decellularization of biological matrices induces the loss of major histocompatibility complex (MHC), which is expected to promote an immunological response by the host. All the studies showed that decellularized biomaterials possess adequate properties for xenografting. Concerning their mechanical properties, several studies have demonstrated that, although chemical decellularization methods do not affect the scaffolds’ mechanical properties, these materials can be modified through different treatments in order to provide the desired mechanical characteristics, depending on the specific application. A short overview of legislative issues concerning the use of decellularized substitutes and future perspectives in surgical applications is also presented. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献