全文获取类型
收费全文 | 4032篇 |
免费 | 280篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 123篇 |
妇产科学 | 99篇 |
基础医学 | 676篇 |
口腔科学 | 59篇 |
临床医学 | 415篇 |
内科学 | 807篇 |
皮肤病学 | 95篇 |
神经病学 | 429篇 |
特种医学 | 101篇 |
外科学 | 374篇 |
综合类 | 22篇 |
一般理论 | 4篇 |
预防医学 | 424篇 |
眼科学 | 32篇 |
药学 | 284篇 |
中国医学 | 7篇 |
肿瘤学 | 360篇 |
出版年
2023年 | 13篇 |
2022年 | 35篇 |
2021年 | 84篇 |
2020年 | 46篇 |
2019年 | 76篇 |
2018年 | 81篇 |
2017年 | 56篇 |
2016年 | 74篇 |
2015年 | 87篇 |
2014年 | 101篇 |
2013年 | 229篇 |
2012年 | 250篇 |
2011年 | 229篇 |
2010年 | 161篇 |
2009年 | 154篇 |
2008年 | 244篇 |
2007年 | 275篇 |
2006年 | 261篇 |
2005年 | 291篇 |
2004年 | 212篇 |
2003年 | 247篇 |
2002年 | 242篇 |
2001年 | 28篇 |
2000年 | 27篇 |
1999年 | 46篇 |
1998年 | 55篇 |
1997年 | 50篇 |
1996年 | 48篇 |
1995年 | 45篇 |
1994年 | 33篇 |
1993年 | 33篇 |
1992年 | 21篇 |
1991年 | 18篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 14篇 |
1987年 | 15篇 |
1986年 | 15篇 |
1985年 | 13篇 |
1984年 | 14篇 |
1983年 | 18篇 |
1982年 | 32篇 |
1981年 | 19篇 |
1980年 | 21篇 |
1979年 | 17篇 |
1978年 | 14篇 |
1971年 | 14篇 |
1963年 | 10篇 |
1961年 | 10篇 |
1960年 | 12篇 |
排序方式: 共有4335条查询结果,搜索用时 0 毫秒
91.
Medina-Palacios Sara Edith Vitales-Noyola Marlen López-González Emmanuel González-Amaro Ana María Méndez-González Verónica Pozos-Guillén Amaury 《Odontology / the Society of the Nippon Dental University》2021,109(3):596-604
Odontology - Secondary/persistent infections are present in teeth with previous root canal treatment, and a great variety of anaerobic microorganisms has been observed in these infections. The... 相似文献
92.
Bur?in ünlü Ince Pim Cuijpers Edith van 't Hof Wouter van Ballegooijen Helen Christensen Heleen Riper 《Journal of medical Internet research》2013,15(10)
Background
Turkish migrants living in the Netherlands have a high prevalence of depressive disorders, but experience considerable obstacles to accessing professional help. Providing easily accessible Internet treatments may help to overcome these barriers.Objective
The aim of this study was to evaluate the effectiveness of a culturally sensitive, guided, self-help, problem-solving intervention through the Internet for reducing depressive symptoms in Turkish migrants.Methods
A two-armed randomized controlled trial was conducted. The primary outcome measure was the severity of depressive symptoms; secondary outcome measures were somatic symptoms, anxiety, quality of life, and satisfaction with the treatment. Participants were assessed online at baseline, posttest (6 weeks after baseline), and 4 months after baseline. Posttest results were analyzed on the intention-to-treat sample. Missing values were estimated by means of multiple imputation. Differences in clinical outcome between groups were analyzed with a t test. Cohen’s d was used to determine the between-groups effect size at posttreatment and follow-up.Results
Turkish adults (N=96) with depressive symptoms were randomized to the experimental group (n=49) or to a waitlist control group (n=47). High attrition rates were found among the 96 participants of which 42% (40/96) did not complete the posttest (6 weeks) and 62% (59/96) participants did not complete the follow-up assessment at 4 months. No significant difference between the experimental group and the control group was found for depression at posttest. Recovery occurred significantly more often in the experimental group (33%, 16/49) than in the control group (9%, 4/47) at posttest (P=.02). Because of the high attrition rate, a completers-only analysis was conducted at follow-up. The experimental group showed significant improvement in depression compared to the control group both at posttest (P=.01) and follow-up (P=.01).Conclusions
The results of this study did not show a significant effect on the reduction of depressive symptoms. However, the effect size at posttest was high, which might be an indicator of the possible effectiveness of the intervention when assessed in a larger sample and robust trial. Future research should replicate our study with adequately powered samples.Trial Registration
Dutch Trial Register: NTR2303. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2303 (Archived by WebCite at http://www.webcitation.org/6IOxNgoDu). 相似文献93.
94.
Yang OO Boscardin WJ Matud J Hausner MA Hultin LE Hultin PM Shih R Ferbas J Siegal FP Shodell M Shearer GM Grene E Carrington M O'Brien S Price CB Detels R Jamieson BD Giorgi JV 《AIDS research and human retroviruses》2002,18(14):1051-1065
The host immune factors that determine susceptibility to HIV-1 infection are poorly understood. We compared multiple immunologic parameters in three groups of HIV-1-seronegative men: 14 highly exposed (HR10), 7 previously reported possibly to have sustained transient infection (PTI), and a control group of 14 low risk blood bank donors (BB). Virus-specific cellular immune assays were performed for CD4(+) T helper cell responses, CD8(+) cytotoxic T lymphocyte activity, CD8(+) cell chemokine release, and CD8(+) cell-derived antiviral soluble factor activity. General immune parameters evaluated included CCR5 genotype and phenotype, interferon alpha production by PBMCs, leukocyte subset analysis, and detailed T lymphocyte phenotyping. Comparisons revealed no detectable group-specific differences in measures of virus-specific immunity. However, the HR10 group differed from the BB group in several general immune parameters, having higher absolute monocyte counts, higher absolute CD8(+) T cell counts and percentages, lower naive and higher terminal effector CD8(+) cells, and lower levels of CD28(+)CD8(+) cells. These changes were not associated with seropositivity for other chronic viral infections. The PTI men appeared to have normal levels of monocytes and slightly elevated levels of CD8(+) T cells (also with increased effector and decreased naive cells). Although we cannot entirely exclude the contribution of other chronic viral infections, these findings suggest that long-lived systemic cellular antiviral immunity as detected by our assays is not a common mechanism for resistance to infection, and that resistance may be multifactorial. General immune parameters reflected by CD8(+) T cell levels and activation, and monocyte concentrations may affect the risk of infection with HIV-1, and/or serve as markers of exposure. 相似文献
95.
Emi Sasagawa Hirotsugu Aiga Edith Yanira Corado Soriano Blanca Leticia Cuyuch Marroquín Marta Alicia Hernández Ramírez Ana Vilma Guevara de Aguilar José Eduardo Romero Chévez Hector Manuel Ramos Hernández Rafael Antonio Cedillos Chizuru Misago Kiyoshi Kita 《The American journal of tropical medicine and hygiene》2015,93(2):326-333
To estimate the incidence (any mother to child) and rate (from seropositive mother to child) of mother-to-child transmission of Trypanosoma cruzi, a serological census was conducted, targeting pregnant women and infants born to seropositive mothers, in four municipalities of El Salvador. Of 943 pregnant women, 36 (3.8%) were seropositive for T. cruzi. Of 36, 32 proceeded to serological tests of their infants when they became 6–8 months of age. Six infants seropositive at the age of 6–8 months further proceeded to second-stage serological test at the age of 9–16 months. As the result, one infant was congenitally infected. Thus, serological tests at the age of 6–8 months produced five false positives. To ensure earlier effective medication only for true positives, identification of seropositive infants at the age of 9–16 months is crucial. Incidence and rate of mother-to-child transmission were 0.14 (per 100 person-years) and 4.0%, respectively. Estimated number of children infected through mother-to-child transmission in El Salvador (170 per year) was much higher than that of human immunodeficiency virus (HIV; seven per year). It is recommended that serological testing for T. cruzi be integrated into those for HIV and syphilis as part of antenatal care package. 相似文献
96.
Castaman G Lethagen S Federici AB Tosetto A Goodeve A Budde U Batlle J Meyer D Mazurier C Fressinaud E Goudemand J Eikenboom J Schneppenheim R Ingerslev J Vorlova Z Habart D Holmberg L Pasi J Hill F Peake I Rodeghiero F 《Blood》2008,111(7):3531-3539
We have prospectively evaluated the biologic response to desmopressin in 77 patients with type 1 von Willebrand disease (VWD) enrolled within the Molecular and Clinical Markers for the Diagnosis and Management of type 1 VWD project. Complete response to desmopressin was defined as an increase of both ristocetin cofactor activity (VWF:RCo) and factor VIII coagulant activity (FVIII:C) to 50 IU/dL or higher and partial response as VWF:RCo or FVIII:C lower than 50 IU/dL after infusion, but at least 3-fold the basal level. Complete response was observed in 83% of patients; partial in 13%; and no response in 4%. Patients with some abnormality of VWF multimeric pattern had significantly lower basal FVIII:C and VWF, lower VWF:RCo/Ag ratio, and less complete responses to desmopressin than patients with a normal multimeric pattern (P=.002). Patients with mutations at codons 1130 and 1205 in the D'-D3 domain had the greatest relative increase, but shortest FVIII and VWF half-lives after infusion. Most partial and nonresponsive patients had mutations in the A1-A3 domains. Response to desmopressin in these VWD patients seemed to be associated with the location of the causative mutation. The presence of subtle multimeric abnormalities did not hamper potential clinically useful responses, as in typical type 1 VWD. 相似文献
97.
Perceptions of age and perceptions of health have each been found to predict future health and well-being, yet surprisingly, studies typically focused on one or the other. Studies on perceived age suggested that its effects on longevity may be mediated by perceived health. Within each of these lines of research, the constructs have not been consistently operationalized, making it difficult to generalize across studies. We aimed to investigate the associations of different measures of perceptions of age and of health with one another and with longevity. Data collected at baseline from the 851 participants of the Rutgers Aging and Health longitudinal study (mean age 73) included perceptions of age and health, each assessed with four different single-item measures, sociodemographic, and health measures. Mortality was followed-up for 10 years. All four health perceptions and two of the age perceptions (Age-group identity and nearness-to-death) were associated with survival time. Age and health perceptions had similar independent effects in models that included measures of both types, controlling for demographics and chronic conditions, though not after controlling for age. In contrast with our hypothesis, health perceptions did not mediate the association between age perceptions and mortality. Findings regarding health perceptions were generally consistent across measures, whereas age perception measures differed in their associations with various outcomes, indicating that they assess different subjective age constructs. The findings correspond with proposed explanations for the predictive effect of age and health perceptions and support the significant though weaker independent effects of age perceptions compared with health perceptions. 相似文献
98.
99.
100.
Natalie M. Zahr Dirk Mayer Torsten Rohlfing Edith V. Sullivan Adolf Pfefferbaum 《Brain pathology (Zurich, Switzerland)》2014,24(6):654-664
Neuroinflammatory mechanisms contribute to the brain pathology resulting from human immunodeficiency virus (HIV) infection. Magnetic resonance spectroscopy (MRS) has been touted as a suitable method for discriminating in vivo markers of neuroinflammation. The present MRS study was conducted in four groups: alcohol dependent (A, n = 37), HIV‐infected (H, n = 33), alcohol dependent + HIV infected (HA, n = 38) and healthy control (C, n = 62) individuals to determine whether metabolites would change in a pattern reflecting neuroinflammation. Significant four‐group comparisons were evident only for striatal choline‐containing compounds (Cho) and myo‐inositol (mI), which follow‐up analysis demonstrated were due to higher levels in HA compared with C individuals. To explore the potential relevance of elevated Cho and mI, correlations between blood markers, medication status and alcohol consumption were evaluated in H + HA subjects. Having an acquired immune deficiency syndrome (AIDS)‐defining event or hepatitis C was associated with higher Cho; lower Cho levels, however, were associated with low thiamine levels and with highly active antiretroviral HIV treatment (HAART). Higher levels of mI were related to greater lifetime alcohol consumed, whereas HAART was associated with lower mI levels. The current results suggest that competing mechanisms can influence in vivo Cho and mI levels, and that elevations in these metabolites cannot necessarily be interpreted as reflecting a single underlying mechanism, including neuroinflammation. 相似文献