全文获取类型
收费全文 | 1364篇 |
免费 | 89篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 33篇 |
妇产科学 | 21篇 |
基础医学 | 176篇 |
口腔科学 | 32篇 |
临床医学 | 184篇 |
内科学 | 249篇 |
皮肤病学 | 16篇 |
神经病学 | 168篇 |
特种医学 | 34篇 |
外科学 | 142篇 |
综合类 | 5篇 |
一般理论 | 1篇 |
预防医学 | 192篇 |
眼科学 | 12篇 |
药学 | 122篇 |
中国医学 | 4篇 |
肿瘤学 | 62篇 |
出版年
2023年 | 9篇 |
2022年 | 17篇 |
2021年 | 22篇 |
2020年 | 26篇 |
2019年 | 37篇 |
2018年 | 35篇 |
2017年 | 56篇 |
2016年 | 42篇 |
2015年 | 39篇 |
2014年 | 37篇 |
2013年 | 69篇 |
2012年 | 102篇 |
2011年 | 93篇 |
2010年 | 53篇 |
2009年 | 54篇 |
2008年 | 86篇 |
2007年 | 100篇 |
2006年 | 94篇 |
2005年 | 94篇 |
2004年 | 77篇 |
2003年 | 70篇 |
2002年 | 57篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 10篇 |
1997年 | 15篇 |
1996年 | 13篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 8篇 |
1974年 | 3篇 |
1970年 | 2篇 |
1969年 | 4篇 |
1967年 | 2篇 |
1966年 | 6篇 |
排序方式: 共有1455条查询结果,搜索用时 15 毫秒
201.
Content of redox-active compounds (ie, antioxidants) in foods consumed in the United States 总被引:1,自引:0,他引:1
Halvorsen BL Carlsen MH Phillips KM Bøhn SK Holte K Jacobs DR Blomhoff R 《The American journal of clinical nutrition》2006,84(1):95-135
BACKGROUND: Supplements containing ascorbic acid, alpha-tocopherol, or beta-carotene do not protect against oxidative stress-related diseases in most randomized intervention trials. We suggest that other redox-active phytochemicals may be more effective and that a combination of different redox-active compounds (ie, antioxidants or reductants) may be needed for proper protection against oxidative damage. OBJECTIVE: We aimed to generate a ranked food table with values for total content of redox-active compounds to test this alternative antioxidant hypothesis. DESIGN: An assay that measures the total concentration of redox-active compounds above a certain cutoff reduction potential was used to analyze 1113 food samples obtained from the US Department of Agriculture National Food and Nutrient Analysis Program. RESULTS: Large variations in the content of antioxidants were observed in different foods and food categories. The food groups spices and herbs, nuts and seeds, berries, and fruit and vegetables all contained foods with very high antioxidant contents. Most food categories also contained products almost devoid of antioxidants. Of the 50 food products highest in antioxidant concentrations, 13 were spices, 8 were in the fruit and vegetables category, 5 were berries, 5 were chocolate-based, 5 were breakfast cereals, and 4 were nuts or seeds. On the basis of typical serving sizes, blackberries, walnuts, strawberries, artichokes, cranberries, brewed coffee, raspberries, pecans, blueberries, ground cloves, grape juice, and unsweetened baking chocolate were at the top of the ranked list. CONCLUSION: This ranked antioxidant food table provides a useful tool for investigations into the possible health benefit of dietary antioxidants. 相似文献
202.
Flint A Møller BK Raben A Sloth B Pedersen D Tetens I Holst JJ Astrup A 《The American journal of clinical nutrition》2006,84(6):1365-1373
BACKGROUND: The importance of the postprandial glycemic and insulinemic responses for appetite and energy intake (EI) is controversial. OBJECTIVE: The aim of the study was to test the hypothesis that postprandial appetite sensations and subsequent EI are determined by postprandial glycemic and insulinemic responses after the intake of a range of breakfast meals. DESIGN: The study was a randomized, crossover meal test including 28 healthy young men, each of whom tested 10 of 14 breakfast meals. Each meal contained 50 g carbohydrate with various glycemic index and energy and macronutrient contents. Blood samples were taken, and appetite sensations were measured 3 h after the meals. Subsequently, EI at lunch (EI(lunch)) was recorded. RESULTS: The glycemic response was unrelated to appetite sensations, whereas the insulinemic response was positively associated with postprandial fullness (R2 = 0.33, P < 0.05). In contrast, the insulinemic response was unrelated to the subsequent EI(lunch), whereas the glycemic response was positively associated with EI(lunch) (R2 = 0.33, P < 0.05). Although no significant difference in EI(lunch) was observed between different breakfast conditions, a low breakfast EI was associated with a high EI(lunch) (R2 = 0.60, P < 0.001). CONCLUSIONS: The current study does not support the contention that the postprandial glycemic response has an important effect on short-term appetite sensations, but a low-glycemic index meal may reduce subsequent EI. In contrast, postprandial insulin seems to affect short-term appetite sensations. 相似文献
203.
Henriksen M Simonsen EB Graven-Nielsen T Lund H Danneskiold-Samsøe B Bliddal H 《Acta orthopaedica》2006,77(4):650-656
Background Impulsive forces in the knee joint have been suspected to be a co-factor in the development and progression of knee osteoarthritis. We thus evaluated the impulsive sagittal ground reaction forces (iGRF), shock waves and lower extremity joint kinematics at heel strike during walking in knee osteoarthritis (OA) patients and compared them to those in healthy subjects.
Subjects and methods We studied 9 OA patients and 10 healthy subjects using three-dimensional gait analyses concentrated on the heel strike. Impulse GRF (iGRF) was measured together with peak accelerations (PA) at the tibial tuberosity and sacrum. Sagittal lower extremity joint angles at heel strike were extracted from the gait analyses. As OA is painful and pain might alter movement strategies, the patient group was also evaluated following pain relief by intraarticular lidocaine injections.
Results The two groups showed similar iGRF, similar tibial and sacral PA, and similar joint angles at heel strike. Following pain relief, the OA patients struck the ground with more extended hip and knee joints and lower tibial PA compared to the painful condition. Although such changes occurred after pain relief, all parameters were within their normal ranges.
Interpretation OA patients and healthy subjects show similar impulse-forces and joint kinematics at heel strike. Following pain relief in the patient group, changes in tibial PA and in hip and knee joint angles were observed but these were still within the normal range. Our findings make us question the hypothesis that impulse-forces generated at heel strike during walking contribute to progression of OA. 相似文献
Subjects and methods We studied 9 OA patients and 10 healthy subjects using three-dimensional gait analyses concentrated on the heel strike. Impulse GRF (iGRF) was measured together with peak accelerations (PA) at the tibial tuberosity and sacrum. Sagittal lower extremity joint angles at heel strike were extracted from the gait analyses. As OA is painful and pain might alter movement strategies, the patient group was also evaluated following pain relief by intraarticular lidocaine injections.
Results The two groups showed similar iGRF, similar tibial and sacral PA, and similar joint angles at heel strike. Following pain relief, the OA patients struck the ground with more extended hip and knee joints and lower tibial PA compared to the painful condition. Although such changes occurred after pain relief, all parameters were within their normal ranges.
Interpretation OA patients and healthy subjects show similar impulse-forces and joint kinematics at heel strike. Following pain relief in the patient group, changes in tibial PA and in hip and knee joint angles were observed but these were still within the normal range. Our findings make us question the hypothesis that impulse-forces generated at heel strike during walking contribute to progression of OA. 相似文献
204.
Carey AL Steinberg GR Macaulay SL Thomas WG Holmes AG Ramm G Prelovsek O Hohnen-Behrens C Watt MJ James DE Kemp BE Pedersen BK Febbraio MA 《Diabetes》2006,55(10):2688-2697
Although interleukin-6 (IL-6) has been associated with insulin resistance, little is known regarding the effects of IL-6 on insulin sensitivity in humans in vivo. Here, we show that IL-6 infusion increases glucose disposal without affecting the complete suppression of endogenous glucose production during a hyperinsulinemic-euglycemic clamp in healthy humans. Because skeletal muscle accounts for most of the insulin-stimulated glucose disposal in vivo, we examined the mechanism(s) by which IL-6 may affect muscle metabolism using L6 myotubes. IL-6 treatment increased fatty acid oxidation, basal and insulin-stimulated glucose uptake, and translocation of GLUT4 to the plasma membrane. Furthermore, IL-6 rapidly and markedly increased AMP-activated protein kinase (AMPK). To determine whether the activation of AMPK mediated cellular metabolic events, we conducted experiments using L6 myotubes infected with dominant-negative AMPK alpha-subunit. The effects described above were abrogated in AMPK dominant-negative-infected cells. Our results demonstrate that acute IL-6 treatment enhances insulin-stimulated glucose disposal in humans in vivo, while the effects of IL-6 on glucose and fatty acid metabolism in vitro appear to be mediated by AMPK. 相似文献
205.
206.
207.
208.
D Bente 《EEG-EMG Zeitschrift für Elektroenzephalographie, Elektromyographie und verwandte Gebiete》1984,15(4):173-179
Quantitative methods for electroencephalographic assessment of vigilance must be oriented along certain principal sign patterns on the one hand, and must also take into account the dynamics of vigilance on the other. The more differentiated the approach, the more efficient will the determination be. Such quantitative methods can supply us with on-target and detailed information on the structure and dynamics of the neural processes involved in the regulation of vigilance, over and above the information supplied via visual analyses. 相似文献
209.
210.
Ostrowski SR Ullum H Goka BQ Høyer-Hansen G Obeng-Adjei G Pedersen BK Akanmori BD Kurtzhals JA 《The Journal of infectious diseases》2005,191(8):1331-1341
BACKGROUND: Blood concentrations of soluble urokinase-type plasminogen activator receptor (suPAR) are increased in conditions with immune activation, and high concentrations of suPAR often predict a poor clinical outcome. This study explored the hypothesis that high plasma concentrations of suPAR are associated with disease severity in malaria. METHODS: At admission to the hospital, plasma concentrations of suPAR were measured by ELISA in samples from 645 African children with clinical symptoms of malaria: 478 had malaria, and 167 had a blood film negative for Plasmodium parasites. Fourteen healthy children were included for comparison. RESULTS: Plasma concentrations of suPAR were higher in patients with malaria (median, 7.90 ng/mL [interquartile range [IQR], 6.56-9.15 ng/mL]), compared with those in plasmodium-negative patients (median, 5.59 ng/mL [IQR, 4.54-8.16 ng/mL]; P < .001) and those in healthy children (3.94 ng/mL [IQR, 3.46-4.82 ng/mL]; P < .001). The highest concentrations were found in patients with malaria who died (P = .008) or had complicated malaria (P < .001). In univariate logistic regression analysis, a 1 ng/mL increase in plasma concentration of suPAR was associated with increased risk of mortality (odds ratio, 1.42 [95% confidence interval, 1.09-1.86]; P = .009). In multivariate linear regression analysis, lower platelet count, lower hemoglobin level, and higher neutrophil count were independently associated with a higher plasma concentration of suPAR. CONCLUSIONS: If the plasma concentration of suPAR reflects the extent of parasite-induced immune activation, this may explain why a high concentration of suPAR is associated with a poor clinical outcome in patients with malaria. 相似文献