全文获取类型
收费全文 | 1906篇 |
免费 | 100篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 35篇 |
妇产科学 | 22篇 |
基础医学 | 319篇 |
口腔科学 | 47篇 |
临床医学 | 133篇 |
内科学 | 358篇 |
皮肤病学 | 38篇 |
神经病学 | 260篇 |
特种医学 | 28篇 |
外科学 | 151篇 |
综合类 | 5篇 |
预防医学 | 243篇 |
眼科学 | 11篇 |
药学 | 191篇 |
中国医学 | 6篇 |
肿瘤学 | 176篇 |
出版年
2023年 | 7篇 |
2022年 | 19篇 |
2021年 | 46篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 36篇 |
2017年 | 30篇 |
2016年 | 39篇 |
2015年 | 42篇 |
2014年 | 72篇 |
2013年 | 95篇 |
2012年 | 139篇 |
2011年 | 147篇 |
2010年 | 77篇 |
2009年 | 63篇 |
2008年 | 136篇 |
2007年 | 140篇 |
2006年 | 139篇 |
2005年 | 129篇 |
2004年 | 157篇 |
2003年 | 134篇 |
2002年 | 116篇 |
2001年 | 18篇 |
2000年 | 11篇 |
1999年 | 17篇 |
1998年 | 18篇 |
1997年 | 19篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1972年 | 2篇 |
1967年 | 2篇 |
1961年 | 1篇 |
排序方式: 共有2033条查询结果,搜索用时 0 毫秒
61.
Perinatal and intrafamily transmission of hepatitis B virus in three generations of a low-prevalence population 总被引:2,自引:0,他引:2
Ordög K Szendrôi A Szarka K Kugler Z Csire M Kapusinszky B Xie J Csizmadia K Brojnás J Rusvai E Tempfli A Berencsi G 《Journal of medical virology》2003,70(2):194-204
Family members of 47 hepatitis B virus (HBV)-carrier pregnant women were tested for the presence of hepatitis B surface antigen (HBsAg), other markers of HBV infection, and hepatitis A virus (HAV) antibodies. Eleven members of six families were found to be HBV DNA positive. Five of the anti-HBe-positive persons were found to be HBV DNA carriers, too. The mean age of the HBV DNA carriers was found to be lower than that of Hbe carriers; therefore, it is suggested that seroconversion to HBe occurs before the resolution of HBV DNA carrier state. Superinfection with hepatitis A virus was not found to influence the elimination of HBV-carrier state, as there was no correlation found between the hepatitis A exposure and the hepatitis B virus markers in the families. The low HBV prevalence in the population (0.3%) was in contrast to the high prevalence of the families of the HBV-carrier mothers (27.1%) and family members with HBV markers (50.4%). Significant positive correlation was found in the proportion of HBV-positive children, and the HBV history of their parents. When fathers were shown to be seronegative, the probability of HBV transmission was reduced by a factor of 6 (12.5% instead of 75%) probably due to reduced viral load and possibly by other factors. Several results indicate, that the noncytocidal hepatitis B virus clearing mechanism suggested by Guidotti et al. [1996, 1999] was effective also in the HBV-carrier human population. 相似文献
62.
Chlamydophila (Chlamydia) pneumoniae induces histidine decarboxylase production in the mouse lung 总被引:4,自引:0,他引:4
Burián K Hegyesi H Buzás E Endrész V Kis Z Falus A Gönczöl E 《Immunology letters》2003,89(2-3):229-236
Chlamydophila (Chlamydia) pneumoniae (C. pneumoniae) is the third most common cause of community-acquired pneumonia and is probably involved in the development of certain chronic inflammatory diseases, including atherosclerosis and adult-onset asthma. Histamine, synthesized by histidine decarboxylase (HDC) from L-histidine, plays an essential role in allergic and inflammatory processes and in cell differentiation. The effect of C. pneumoniae infection on the expression of HDC has not been examined. In the present study, normal Balb/c mice and HDC knockouts, and control mice with a CD1 background were infected intranasally with C. pneumoniae. On days 1, 3, 7, 16 and 31 after infection, the normal Balb/c mice were sacrificed and divided into three groups. In the homogenized lungs of the first group, C. pneumoniae titres were determined and demonstrated peak levels on day 7. HDC production was revealed by a Western blot assay throughout the observation period of 1-16 days, and cytokine concentrations were determined by ELISA. The interleukin-3 (IL-3) and interleukin-6 (IL-6) levels were highest on day 1 and on days 1-3, respectively; the interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) levels reached the maximum on day 7, but the quantity of IL-4 was still three times higher than that in the control group 16 days after infection. The lungs of the mice in the second group were processed for the in situ demonstration of HDC activity, while the lungs in the third group were stained for C. pneumoniae antigen. The HDC activity was increased predominantly in the bronchial epithelial cells, while C. pneumoniae antigens were expressed especially in the interstitial macrophages. The HDC knockout mice exhibited a higher survival rate after C. pneumoniae infection than did the control mice. These results point to a strong association between local histamine production and other inflammatory mediators and are novel in demonstrating the role of histamine in the pathomechanism of C. pneumoniae infections. 相似文献
63.
Altered calcium handling is an early sign of streptozotocin-induced diabetic cardiomyopathy 总被引:1,自引:0,他引:1
Ligeti L Szenczi O Prestia CM Szabó C Horváth K Marcsek ZL van Stiphout RG van Riel NA Op den Buijs J Van der Vusse GJ Ivanics T 《International journal of molecular medicine》2006,17(6):1035-1043
The main objective of the present study was to determine alterations of calcium handling in the diabetic rat heart during the transition from adaptive to maladaptive phase of cardiomyopathy. By inhibiting the nuclear enzyme poly(ADP-ribose) polymerase (PARP), we also investigated the possible role of this enzyme in the sequence of pathological events. Six weeks after induction of type I diabetes by injection of streptozotocin in rats, the hearts were perfused according to Langendorff. Intracellular-free calcium (Ca(2+)(i)) levels were measured by surface fluorometry using Indo-1 AM. Cyclic changes in Ca(2+)(i) concentrations and hemodynamic parameters were measured simultaneously. The hearts were challenged by infusion of isoproterenol. Six weeks of diabetes resulted in reduced inotropy and lusitropy. The diabetic hearts (DM) expressed a significantly elevated end-diastolic Ca(2+)(i) level (control, 111-/+20 vs DM, 221-/+35 nM). The maximal transport capacity of SERCA2a and conductance of RyR2 were reduced. These changes were not accompanied by major alterations in the tissue content of SERCA2a, RyR2, phospholamban and Na(+)/Ca(2+) exchanger. In response to beta-adrenergic activation, SERCA2a transport capacity and RyR2 conductance were stunted in the DM hearts. Inhibition of PARP induced minor changes in the mechanical function and calcium handling of the DM hearts. In conclusion, the observed changes in contractility and in Ca(2+)(i) handling are most likely attributable to functional disturbances of SERCA2a and RyR2 in this transitional phase of diabetes. At this stage of diabetes, PARP does not appear to play a significant pathogenetic role in the alterations in contractile function and calcium handling. 相似文献
64.
Regina Felső Éva Lányi Éva Erhardt Zsófia Laufer Dániel Kardos Róbert Herczeg Attila Gyenesei Katalin Hollódy Dénes Molnár 《Journal of sleep research》2023,32(2):e13746
Ghrelin, a regulator of food intake and energy expenditure, has been shown to be associated with insufficient sleep. The goal of the present study was to investigate the effect of a single night of total sleep deprivation on fasting saliva ghrelin and on nocturnal variation of saliva ghrelin concentration. A further aim of the study was to investigate the influence of body mass index on changes in saliva ghrelin levels. Altogether 35 adolescents (18 boys; age: 13.8 ± 1.14 years) were studied on two subsequent days (sleep and total sleep deprivation). Saliva samples were collected during the two experimental nights at 21:00 hours, 01:00 hours and 06:00 hours. Total-ghrelin concentration showed a continuous increase from the evening until 06:00 hours. This increase was blunted significantly (p = 0.003) by total sleep deprivation. Total-ghrelin level was significantly lower (p = 0.02) during total sleep deprivation at 06:00 hours (median 403.6 pg ml−1; 95% confidence interval: 343.1–468.9 pg ml−1) as compared with values during the sleep condition (median 471.2 pg ml−1; 95% confidence interval: 205.4–1578.7 pg ml−1). Acyl-ghrelin levels did not present any change at the three time points, and were not affected by total sleep deprivation. Stratifying the study population according to body mass index (normal weight and overweight/obese groups), the blunting effect of total sleep deprivation was more pronounced in the obese/overweight group (sleep: median 428.2 pg ml−1; 95% confidence interval: 331.3–606.9 pg ml−1 versus total sleep deprivation: median 333.1 pg ml−1; 95% confidence interval: 261.5–412.9 pg ml−1; p = 0.0479). Saliva total-ghrelin concentrations gradually increased during the night, and total sleep deprivation significantly blunted this increase. This blunting effect was mainly observed in subjects with overweight/obesity. The physiological and clinical implications of the present observation are to be clarified by further studies. 相似文献
65.
The use of HLA transgenic mice in models of immunity and diseaseassumes that human MHC molecules are able to contribute towardthe positive selection of the mouse TCR repertoire. As an initialstep towards analysis of this we have compared the relativeability of DR/Eß or E/Eß complexes to induceT cell receptor (TCR) positive selection in H-2Ea and HLA-DRAtransgenic mice lacking endogenous E. The results show that,like E/Eß, the hybrid DR/ß complexes arecapable of mediating positive selection of Vß2+;,Vß6+, and Vß10+ cells. However, differenceswere found between the effects of the two transgenes. Thus,while Vß6+ cells were efficiently selected in bothH-2Ea and DRA transgenic mice, positive selection of Vß10+cells was less apparent in the DRA transgenic mice. Variationbetween Ea and DRA transgenic mice is consistent with the notionthat this process is dependent on differential binding of endogenouspeptides to the E/Eß and DR/Eß complexes.Furthermore, contrary to expectations, in neither set of micewas positive selection limited solely to the CD4+ subset. Thus,examples were found in which Vß-specific positiveselection was confined to either the CD4+ or CD8+ subsets, andothers in which both subpopulations were concomltantly increased.In the case of Vß2 positive selection, H-2Ea transgenicmice showed expansion of these cells in both the CD4+ and CD8+subpopulations whlle in DRA transgenic mice this occurred predominantlyin the CD8+ subpopulatlon. 相似文献
66.
Swathi Gujral Meryl A. Butters Alexandre Y. Dombrovski Katalin Szanto 《The American journal of geriatric psychiatry》2021,29(7):709-713
ObjectivesThis study examined whether late-onset (versus early-onset) suicidal behavior is associated with worse cognition.MethodsParticipants included 278 adults aged 50+ years (56 nonpsychiatric comparison group; 67 nonsuicidal depressed older adults; 63 depressed suicide ideators; and 44 late-onset (55+ years) and 48 early-onset suicide attempters (<55 years). Using a case-control design, this study examined group differences in global cognition, episodic memory, information processing speed, and executive functioning, assessed using the Repeatable Battery of Neuropsychological Status and the Trail Making Test from the Delis-Kaplan Executive Function System. Linear regression was used for data analyses.ResultsBoth attempter groups displayed worse executive functioning than nonsuicidal depressed older adults. Late-onset attempters additionally displayed poorer global cognition and processing speed than nonsuicidal depressed older adults and poorer memory than early-onset attempters.ConclusionsLate-onset suicidal behavior is associated with worse performance in a broad range of cognitive domains, possibly reflective of a dementia prodrome. 相似文献
67.
68.
Cohen A Gilman SE Houck PR Szanto K Reynolds CF 《Social psychiatry and psychiatric epidemiology》2009,44(4):272-277
BACKGROUND: Separate reports from the maintenance treatment for late-life depression (MTLD) trials have shown that low socioeconomic status (SES) and anxiety symptoms at the time of treatment initiation predict lower levels of response to antidepressant treatment and higher levels of suicidal ideation in older adults. AIM: To determine whether SES and anxiety independently contribute to worse treatment outcomes, as indicated by persistence of depressive symptoms during treatment and the persistence of suicidal ideation. Consistent with prior evidence that sociodemographic factors and clinical history are both prognostic of depression treatment efficacy, we hypothesized that SES and pre-existing anxiety symptoms will both predict lower levels of response to treatment and higher levels of suicidal ideation. METHOD: Secondary analyses of data from the MTLD trials. RESULTS: Regression analyses which controlled for comorbid anxiety indicated that residents of middle- and high-income census tracts were more likely to respond to treatment (HR, 1.63; 95%CI, 1.08-2.46) and less likely to report suicidal ideation during treatment (OR, 0.51; 95%CI, 0.28-0.90) than residents of low income census tracts. The same regression models indicated that pre-existing anxiety symptoms were independently related to lower treatment response (HR, 0.73; 95%CI, 0.60-0.89) and higher risk of suicidal ideation (OR, 1.45; 95%CI, 0.98-2.14). CONCLUSION: These findings demonstrate the importance of treating anxiety symptoms during the course of treatment for late-life depression and, at the same time, addressing barriers to treatment response related to low SES. 相似文献
69.
Zsolt Illes MD PhD Andrea Mike MD PhD Anita Trauninger MD PhD Katalin Várdi MD Márk Váczi PhD 《Muscle & nerve》2014,49(4):603-606
Introduction: The relationship between skeletal muscle strength and respiratory dysfunction in Pompe disease has not been examined by quantitative methods. We investigated correlations among lower extremity proximal muscle strength, respiratory function, and motor performance. Methods: Concentric strength of the knee extensor and flexor muscles was measured with a dynamometer, and pulmonary function was evaluated using spirometry in 7 adult patients. The 6‐minute walk test and the 4‐step stair‐climb test were used for assessing aerobic endurance and anaerobic power, respectively. Results: Anaerobic motor performance correlated with strength of both thigh muscles. Respiratory function did not correlate with either muscle strength or motor function performance. Conclusions: Respiratory and lower extremity proximal muscles could be affected differentially by the disease in individual patients. Motor performance is influenced by thigh muscle strength and is less dependent of respiratory capacity in our cohort of ambulatory patients. Muscle Nerve 49:603–606, 2014 相似文献
70.
Obrosova IG Li F Abatan OI Forsell MA Komjáti K Pacher P Szabó C Stevens MJ 《Diabetes》2004,53(3):711-720
Oxidative and nitrosative stress play a key role in the pathogenesis of diabetic neuropathy, but the mechanisms remain unidentified. Here we provide evidence that poly(ADP-ribose) polymerase (PARP) activation, a downstream effector of oxidant-induced DNA damage, is an obligatory step in functional and metabolic changes in the diabetic nerve. PARP-deficient (PARP(-/-)) mice were protected from both diabetic and galactose-induced motor and sensory nerve conduction slowing and nerve energy failure that were clearly manifest in the wild-type (PARP(+/+)) diabetic or galactose-fed mice. Two structurally unrelated PARP inhibitors, 3-aminobenzamide and 1,5-isoquinolinediol, reversed established nerve blood flow and conduction deficits and energy failure in streptozotocin-induced diabetic rats. Sciatic nerve immunohistochemistry revealed enhanced poly(ADP-ribosyl)ation in all experimental groups manifesting neuropathic changes. Poly(ADP-ribose) accumulation was localized in both endothelial and Schwann cells. Thus, the current work identifies PARP activation as an important mechanism in diabetic neuropathy and provides the first evidence for the potential therapeutic value of PARP inhibitors in this devastating complication of diabetes. 相似文献