全文获取类型
收费全文 | 2860篇 |
免费 | 164篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 92篇 |
妇产科学 | 45篇 |
基础医学 | 281篇 |
口腔科学 | 263篇 |
临床医学 | 236篇 |
内科学 | 595篇 |
皮肤病学 | 21篇 |
神经病学 | 162篇 |
特种医学 | 85篇 |
外科学 | 453篇 |
综合类 | 27篇 |
一般理论 | 1篇 |
预防医学 | 418篇 |
眼科学 | 39篇 |
药学 | 212篇 |
中国医学 | 1篇 |
肿瘤学 | 86篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 41篇 |
2020年 | 31篇 |
2019年 | 45篇 |
2018年 | 49篇 |
2017年 | 40篇 |
2016年 | 44篇 |
2015年 | 38篇 |
2014年 | 70篇 |
2013年 | 146篇 |
2012年 | 152篇 |
2011年 | 173篇 |
2010年 | 90篇 |
2009年 | 78篇 |
2008年 | 188篇 |
2007年 | 198篇 |
2006年 | 178篇 |
2005年 | 199篇 |
2004年 | 190篇 |
2003年 | 199篇 |
2002年 | 186篇 |
2001年 | 57篇 |
2000年 | 36篇 |
1999年 | 62篇 |
1998年 | 52篇 |
1997年 | 44篇 |
1996年 | 39篇 |
1995年 | 22篇 |
1994年 | 24篇 |
1993年 | 28篇 |
1992年 | 25篇 |
1991年 | 25篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 18篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 25篇 |
1984年 | 19篇 |
1983年 | 20篇 |
1982年 | 20篇 |
1981年 | 24篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1966年 | 4篇 |
排序方式: 共有3045条查询结果,搜索用时 15 毫秒
71.
72.
OBJECTIVE: To study the impact of 24 months of strength training on the physical function of patients with early rheumatoid arthritis (RA). METHODS: Seventy patients were assigned to either the strength training (experimental) group (n = 35) or the control group (n = 35). Patients in the experimental group performed strength training for 24 months, and control patients were instructed to perform range of motion exercises. Maximal strength of the knee extensors, trunk flexors, and extensors, as well as grip strength were recorded with dynamometers. Disease activity was assessed by the erythrocyte sedimentation rate and Ritchie's articular index, joint damage was determined by the Larsen x-ray index, and functional capacity was assessed using the Valpar 9 test and the Stanford Health Assessment Questionnaire (HAQ). The employment status of each patient was recorded. RESULTS: In the experimental group, strength training led to significant increases (19-59%) in maximal strength of the trained muscles. Such increases in the control group varied from 1% to 31%. There was a clear training effect on muscular strength in favor of the experimental group, but significant improvements in the HAQ indices as well as in the Valpar 9 test were seen also in control patients. Results of the Valpar 9 and the HAQ were statistically significantly better in patients who remained gainfully employed compared with patients who retired preterm during followup. However, compared with patients who remained in the work force, patients who retired were older, and their work was physically more demanding. CONCLUSION: As expected, strength training led to increased muscle strength, but this increase did not correlate with improved physical function as assessed by the Valpar 9 work sample test. The increased muscle performance did not prevent a substantial proportion of patients from retiring preterm. The 2 items from the Valpar 9 test that were applied were not sensitive enough to differentiate the patients according to their working status. 相似文献
73.
Antibodies to human heat shock protein 60, hypertension and dyslipidemia. A study of joint effects on coronary risk 总被引:3,自引:0,他引:3
Kervinen H Huittinen T Vaarala O Leinonen M Saikku P Manninen V Mänttäri M 《Atherosclerosis》2003,169(2):339-344
OBJECTIVE: High IgA-class (but not IgG-class) Anti-Heat-shock-protein 60 antibody level is a predictor of coronary risk in dyslipidemic middle-aged men. In this paper we studied the joint effects of high Anti-Hsp60-antibody level and the classical coronary risk factors. METHODS: We used nested case-control design and logistic regression analyses. The cases consisted of 233 middle-aged men with myocardial infarction or coronary death during 8.5-year follow-up in Helsinki Heart Study, a coronary primary prevention study with gemfibrozil. The controls were subjects without coronary events, matched for drug treatment and the geographical area. RESULTS: The relative coronary risks (Odds Ratios (ORs); 95% confidence interval) were 1.41 (0.96-2.05) for high IgA-class Anti-Hsp60 antibody level and 1.98 (1.35-2.90) for hypertension, defined as mean arterial pressure >114 mmHg. With simultaneous occurrence of high Anti-Hsp60 antibody level and hypertension, the ORs were 2.32 (1.26-4.27) for systolic and 2.99 (1.63-5.48) for diastolic hypertension. Similar patterns of joint effects were found between high Anti-Hsp60 antibody and lipoprotein cholesterol levels as well as antibodies against oxidized low-density lipoprotein. CONCLUSIONS: Our results suggest that, while high IgA-class Anti-Hsp60 antibody level predicts coronary risk, the effect is modest without simultaneous occurrence of other classical risk factors. 相似文献
74.
75.
Is there any link between insulin resistance and inflammation in established preeclampsia? 总被引:5,自引:0,他引:5
Kaaja R Laivuori H Pulkki P Tikkanen MJ Hiilesmaa V Ylikorkala O 《Metabolism: clinical and experimental》2004,53(11):1433-1435
Both insulin resistance and inflammation may contribute to the onset of preeclampsia. They also could be interrelated. We studied the relationship between inflammatory cytokines and markers of insulin resistance. During their third trimester, 22 proteinuric preeclamptic women and 16 normotensive controls underwent intravenous glucose tolerance test (minimal model). Preeclamptic women were more insulin-resistant (P = .009), and they had higher levels of serum soluble tumor necrosis alpha receptor II (TNFalpha RII) (P = .002), triglycerides (P = .006), uric acid (P = .001), and leptin (P = .002) than did the controls. However, the study groups did not differ in serum TNFalpha, C-reactive protein (CRP), interleukin-6 (IL-6), sex hormone-binding globulin (SHBG), and high-density lipoprotein-2 (HDL(2))-cholesterol. In multiple regression analysis only SHBG (P = .01) and triglycerides (P = .0036) were associated with insulin sensitivity independently of body mass index (BMI), weight gain, HDL(2)-cholesterol, CRP, TNFalpha, and TNFalpha RII, IL-6, and leptin. We conclude that insulin resistance and the inflammatory markers studied were not associated in established preeclampsia. 相似文献
76.
Kalle Hakala Pekka Luukkonen Matti Vuoristo Heikki Järvinen Tatu A. Miettinen 《Journal of hepatology》1997,26(6):1306-1312
Background: Previous studies suggest only minor changes in bile acid metabolism after panproctocolectomy with ileal pouch construction.Aims/Methods: To investigate these changes further, we studied cholesterol absorption and serum, biliary and fecal non-cholesterol sterols and lipids in 12 ileal pouch patients and 10 controls.Results: In patients, cholesterol absorption was markedly reduced and was associated with low serum total and LDL cholesterol and LDL triglyceride levels, but surprisingly, cholesterol synthesis, as indicated by sterol-balance data or serum cholesterol precursor levels, was within low normal limits. The high proportions of serum plant sterol to cholesterol, particularly that of campesterol, were not related to cholesterol absorption, but were attributable to a markedly reduced biliary cholesterol secretion. Interestingly, in these patients the fractional absorption of campesterol was normal, whereas that of sitosterol, like cholesterol, was reduced and was positively related to the intestinal influx of cholesterol. The patients' serum cholestanol proportion was normal, but the proportion of the cholestanol formed during intestinal passage was significantly reduced (17.9% vs 65.2% in controls).Conclusions: Thus ileal pouch patients are characterized by sterol malabsorption, lowered serum total and LDL-cholesterol levels, but unexpectedly without any increase in cholesterol synthesis. The lack of high serum cholestanol, shown earlier frequently in unoperated patients with ulcerative colitis, may indicate reversible cholestasis, a finding deserving further exploration. 相似文献
77.
78.
Antti Kulkas Pekka Tiihonen Petro Julkunen Esa Mervaala Juha Töyräs 《Medical & biological engineering & computing》2013,51(6):697-708
Sleep apnea–hypopnea syndrome (SAHS) causes impairment of daytime functions and increases risk of cardiovascular diseases. Apnea–hypopnea index (AHI), currently used for the estimation of the severity of SAHS, does not contain information on the morphology or duration aspects of the breathing cessations and related oxygen desaturations. Longer breathing cessations and deeper desaturations may have more severe consequences than shorter and shallower ones. To address these issues, novel parameters containing information on the duration and morphology of breathing cessations and oxygen desaturations were calculated and evaluated on 160 male patients (40 patients in normal, mild, moderate and severe AHI severity categories). Obstruction and desaturation duration parameters consist of sum of event durations normalized with the total analysed time. Desaturation severity is a sum of desaturation event areas normalized with total analysed time and obstruction severity parameter is a sum of the products of apnea and hypopnea durations and related desaturation areas normalized with total analysed time. The median follow-up time of the patients was 183 months (range 154–215 months). The 40 patients in each category were further divided into subgroups A and B with lowest and highest novel parameter values, respectively. AHI showed no differences between the subgroups. Mortality was increased in subgroups B compared to subgroups A. The correlation of the novel parameters with AHI was only moderate and the parameter values were partially overlapping between the AHI severity categories. This suggests that patients with similar AHI may in fact suffer from SAHS of very different severity. Thus, the present results suggest that the novel parameters could bring new insight to the individual estimation of the severity of SAHS. 相似文献
79.
Jingwei He Fang Liu Pekka K. Vallittu Lippo V.J. Lassila 《Journal of biomaterials science. Polymer edition》2013,24(4):417-430
In this study, a dimethacrylate monomer, 1,4-Bis[2-(4-(2′-hydroxy-3′-methacryloyloxy-propoxy)phenyl)-2propyl]benzene (BMPPB) was synthesized to replace 2,2-bis[4-(2′-hydroxyl-3′-methacryloyloxy-propoxy)phenyl]propane (Bis-GMA) as one component of dental restorative materials. The structure of BMPPB and its intermediate product 1,4-bis[2-(4-(oxiranylmethoxy)phenyl)-2propyl]benzene (BOPPB) were confirmed by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance spectroscopy (1H-NMR), and elemental analysis. In order to evaluate the possibility of replacing Bis-GMA with BMPPB in dental resin, double bond conversion (DC), polymerization shrinkage, contact angle, water sorption (WS) and solubility (SL), and flexural strength (FS) and modulus of BMPPB/tri(ethylene glycol)dimethacrylate (TEGDMA) (50/50?wt) resin system and Bis-GMA/BMPPB/TEGDMA (25/25/50?wt) resin system were studied. Commercially used Bis-GMA/TEGDMA (50/50?wt) dental resin system was used as reference. The results showed that BMPPB-contained copolymer had higher DC, higher WS and SL than the copolymer that only contained Bis-GMA (p?<?0.05). All of the copolymers had nearly the same contact angle (p?>?0.05). BMPPB/TEGDMA resin system had lower polymerization shrinkage, higher FS and modulus (p?<?0.05) than Bis-GMA/TEGDMA resin system. There was no significant difference on polymerization shrinkage, FS and modulus (p?>?0.05) between Bis-GMA/BMPPB/TEGDMA resin system and Bis-GMA/TEGDMA resin system. Before and after water immersion, both FS and modulus of every copolymer did not change significantly (p?>?0.05). Therefore, BMPPB had potential to be used to replace Bis-GMA as base resin in dental restorative materials, but many studies should be undertaken further. 相似文献
80.
Anu Muraja‐Murro Antti Kulkas Mikko Hiltunen Salla Kupari Taina Hukkanen Pekka Tiihonen Esa Mervaala Juha Töyräs 《Journal of sleep research》2013,22(6):663-669
Obstructive sleep apnea (OSA) is linked to an increased mortality rate. However, the severity of individual obstruction events is rarely considered quantitatively in clinical practice. We hypothesized that OSA with especially severe obstruction events would predispose a patient to greater health risks than OSA with a similar apnea–hypopnea index (AHI), but lower severity of individual events. This hypothesis was tested in a follow‐up (198.2 ± 24.7 months) of a population of 1068 men referred for ambulatory polygraphic recording due to suspected OSA. The recordings were analysed according to the guidelines of the American Academy of Sleep Medicine. Furthermore, a novel obstruction severity parameter was determined; this was defined as the product of duration of the individual obstruction event and area of the related desaturation event. Patients treated with continuous positive airway pressure (CPAP) were omitted. We identified 125 deceased patients from our original population and for 113 of these a matching alive patient with similar AHI, age, body mass index (BMI), smoking habits and follow‐up time could be found. The deceased patients with severe OSA (based on conventional AHI) showed higher obstruction severity values than their AHI‐matched alive controls. Based on the multivariate logistic regression analysis, obstruction severity was the only parameter which was related statistically significantly to mortality in the severe OSA category. Furthermore, 59% of all deceased patients and 83% of those who had severe OSA displayed higher obstruction severity than the AHI‐matched alive counterparts. To conclude, the obstruction severity parameter provided valuable prognostic information supplementing AHI. The obstruction severity parameter might improve recognition of the patients with the highest risk. 相似文献