全文获取类型
收费全文 | 5017篇 |
免费 | 337篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 148篇 |
妇产科学 | 107篇 |
基础医学 | 794篇 |
口腔科学 | 76篇 |
临床医学 | 409篇 |
内科学 | 1396篇 |
皮肤病学 | 126篇 |
神经病学 | 504篇 |
特种医学 | 66篇 |
外科学 | 363篇 |
综合类 | 22篇 |
一般理论 | 3篇 |
预防医学 | 482篇 |
眼科学 | 111篇 |
药学 | 303篇 |
中国医学 | 43篇 |
肿瘤学 | 392篇 |
出版年
2024年 | 7篇 |
2023年 | 84篇 |
2022年 | 184篇 |
2021年 | 275篇 |
2020年 | 121篇 |
2019年 | 178篇 |
2018年 | 200篇 |
2017年 | 141篇 |
2016年 | 159篇 |
2015年 | 183篇 |
2014年 | 220篇 |
2013年 | 285篇 |
2012年 | 424篇 |
2011年 | 456篇 |
2010年 | 174篇 |
2009年 | 171篇 |
2008年 | 298篇 |
2007年 | 253篇 |
2006年 | 246篇 |
2005年 | 217篇 |
2004年 | 221篇 |
2003年 | 187篇 |
2002年 | 196篇 |
2001年 | 24篇 |
2000年 | 20篇 |
1999年 | 27篇 |
1998年 | 30篇 |
1997年 | 33篇 |
1996年 | 24篇 |
1995年 | 21篇 |
1994年 | 14篇 |
1993年 | 17篇 |
1992年 | 19篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 17篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1982年 | 15篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1977年 | 6篇 |
1968年 | 6篇 |
1938年 | 8篇 |
1934年 | 5篇 |
1932年 | 5篇 |
1927年 | 7篇 |
排序方式: 共有5376条查询结果,搜索用时 0 毫秒
21.
Silvia Bianchi Maria Gori Clara Fappani Giulia Ciceri Marta Canuti Daniela Colzani Marco Dura Mara Terraneo Anna Lamberti Melissa Baggieri Sabrina Senatore Marino Faccini Fabio Magurano Elisabetta Tanzi Antonella Amendola 《Viruses》2022,14(5)
Despite the existence of an effective live-attenuated vaccine, measles can appear in vaccinated individuals. We investigated breakthrough measles cases identified during our surveillance activities within the measles/rubella surveillance network (MoRoNet) in Milan and surrounding areas (Northern Italy). Between 2017 and 2021, we confirmed measles virus (genotypes B3 or D8) infections in 653 patients and 51 of these (7.8%) were vaccinees. Among vaccinated individuals whose serum was available, a secondary failure was evidenced in 69.4% (25/36) of cases while 11 patients (30.6%) were non-responders. Non-responders were more frequently hospitalized and had significantly lower Ct values in both respiratory and urine samples. Median age and time since the last immunization were similar in the two groups. Importantly, we identified onward transmissions from vaccine failure cases. Vaccinees were involved in 20 outbreaks, in 10 of them they were able to transmit the virus, and in 8 of them, they were the index case. Comparing viral hemagglutinin sequences from vaccinated and non-vaccinated subjects did not show a specific mutation pattern. These results suggest that vaccination failure was likely due to the poor immune response of single individuals and highlights the importance of identifying breakthrough cases and characterizing their clinical and virologic profiles. 相似文献
22.
Marco Mauri Clara Luigia Gobbo Lucia Princiotta Cariddi Ilaria Schiorlin Maurizio Versino 《Archives of Medical Science》2022,18(4):1108
IntroductionThe detection in mild cognitive impairment (MCI) of metabolic alterations suggestive of depression and/or of evolution to dementia.MethodsSixty-nine MCI patients underwent clinical and imaging evaluation including position emission tomography/computed tomography with fluorodeoxy-glucose (FDG-PET/CT).ResultsThe metabolism mean values in parietal, temporal and pre-cuneus areas were lower in subjects who evolved to dementia, and in frontal and in anterior cingulate areas in depressed subjects. Abnormal metabolism values were higher in the frontal and parietal lobes, and in the precuneus in subjects who evolved to dementia independently from depression.ConclusionsIn MCI FDG-PET/CT abnormality patterns suggest the presence of depression or the evolution to dementia. 相似文献
23.
24.
OBJECTIVE: To assess the utilization rates of and complications associated with inpatient hysterectomy in California between 1991 and 2004. METHODS: We used the California Patient Discharge Database to analyze International Classification of Diseases, 9th Revision, Clinical Modification diagnostic and procedure codes for 649,758 women undergoing inpatient hysterectomy in California between 1991 and 2004 using multiple logistic regression models. RESULTS: Between 1991 and 2004, the incidence of any type of inpatient hysterectomy for benign gynecologic conditions declined 17.6%. The rates of laparoscopically assisted vaginal hysterectomy and subtotal hysterectomy increased substantially. The year of hysterectomy was a factor associated with both medical and surgical complications; the odds of inpatient complications between 1991 and 2004 steadily declined. CONCLUSION: In California between 1991 and 2004, the incidence of inpatient hysterectomy for benign gynecological conditions and the adjusted odds of complications declined substantially. Changes in practice and shorter hospital stays may have affected the changes in inpatient hysterectomy rates and associated inpatient complications. 相似文献
25.
Immunomodulatory and anti-SARS activities of Houttuynia cordata 总被引:1,自引:0,他引:1
Lau KM Lee KM Koon CM Cheung CS Lau CP Ho HM Lee MY Au SW Cheng CH Lau CB Tsui SK Wan DC Waye MM Wong KB Wong CK Lam CW Leung PC Fung KP 《Journal of ethnopharmacology》2008,118(1):79-85
BACKGROUND: Severe acute respiratory syndrome (SARS) is a life-threatening form of pneumonia caused by SARS coronavirus (SARS-CoV). From late 2002 to mid 2003, it infected more than 8000 people worldwide, of which a majority of cases were found in China. Owing to the absence of definitive therapeutic Western medicines, Houttuynia cordata Thunb. (Saururaceae)(HC) was shortlisted by Chinese scientists to tackle SARS problem as it is conventionally used to treat pneumonia. AIM OF THE STUDY: The present study aimed to explore the SARS-preventing mechanisms of HC in the immunological and anti-viral aspects. RESULTS: Results showed that HC water extract could stimulate the proliferation of mouse splenic lymphocytes significantly and dose-dependently. By flow cytometry, it was revealed that HC increased the proportion of CD4(+) and CD8(+) T cells. Moreover, it caused a significant increase in the secretion of IL-2 and IL-10 by mouse splenic lymphocytes. In the anti-viral aspect, HC exhibited significant inhibitory effects on SARS-CoV 3C-like protease (3CL(pro)) and RNA-dependent RNA polymerase (RdRp). On the other hand, oral acute toxicity test demonstrated that HC was non-toxic to laboratory animals following oral administration at 16 g/kg. CONCLUSION: The results of this study provided scientific data to support the efficient and safe use of HC to combat SARS. 相似文献
26.
Clara Nigg 《The Journal of experimental medicine》1935,61(1):17-26
1. Cultures of typhus fever rickettsiae were as a rule found to remain viable and virulent after being stored at 37° and –20°C. for several months, whereas they failed to survive when stored at the intermediate temperatures of 20° and –4°C. for 4 weeks and 10 days respectively. In one instance cultures were stored at 37°C. for 8 months without having been transferred, and were subsequently found to be viable and infectious. 2. The conditions influencing such long survival of an organism which seems to require living tissue for multiplication (as filterable viruses do in general) are discussed. 3. Typhus-infected tissues (minced guinea pig tunica) suspended in a serum-Tyrode mixture in sealed flasks remained infectious at 37°C. for at least 10 weeks. 4. Additional evidence for the etiological significance of the rickettsiae in typhus fever is obtained from the experiments described. 相似文献
27.
1. Rickettsia prowazeki can be cultivated for many generations in vitro, without diminution in numbers or virulence, in media similar to those described by Maitland, Rivers, and others for the cultivation of certain viruses. In all probability, such cultures can be maintained indefinitely. 2. It has been impossible, thus far, to cultivate the typhus rickettsia without employing living tissue. 相似文献
28.
Rona Gigon Grassheim Oberniedermayr Kraas C. Prausnitz Schmitz Weigert Oppenheimer Griesbach Friedemann Flury Goldstein Buschkejun Claus Schilling Buschke Jr Seligmann Lewy Weigert Edens Blumenfeldt Edens Vaternahm Oberniedermayr Hirsch Taterka Herzfeld SchÜbel H. Hirschfeld Rosenow Gottschalk Bernhardt Freudenberg Clara Bender Jonas Goldstein Dietrich Valentin Simon Oberniedermayr 《Journal of molecular medicine (Berlin, Germany)》1931,10(5):224-231
Ohne Zusammenfassung 相似文献
29.
Both caffeine and the perception of refreshment delivered by cooling, tingling, and mouth-watering flavors have individually been shown to positively impact cognitive performance and mood, though presently there is limited evidence on their possible combined effects. This study explored the contribution of refreshing compounds in beverages, namely, carbon dioxide and citric acid, on the acute effects of caffeine on sustained attention and self-rated physical and mental energy. A randomized, controlled crossover trial was conducted by testing three products: a carbonated caffeinated beverage; a comparator caffeinated beverage; and a flavor-matched control beverage. Findings from 24 healthy adults revealed product-dependent variations in cognitive performance during a 60-min visual sustained-attention task, suggesting that the carbonated-caffeinated beverage led to faster, greater and more consistent levels of accuracy, compared to the control beverage. Specifically, significant differences were found between: (1) the carbonated-caffeinated beverage and the caffeinated beverage, and (2) between the caffeinated beverage and the control beverage for number of hits, reaction time and false alarm scores. Both caffeinated beverages led to higher physical and mental energy, and lower physical and mental fatigue 60-min post-consumption. These findings suggest beneficial effects on sustained attention through the combination of caffeine with refreshing compounds. 相似文献
30.
Simone Perna Clara Gasparri Cinzia Ferraris Gaetan Claude Barrile Alessandro Cavioni Francesca Mansueto Zaira Patelli Gabriella Peroni Alice Tartara Marco Zese Mariangela Rondanelli 《Nutrients》2022,14(12)
Background: SARC-F is a simple sarcopenia screening tool. This study aimed to examine the validity of the Italian version of SARC-F. Methods: A total of 97 elderly individuals (37/60 males/females, 65 years and older) who met the study’s selection criteria were included. SARC-F was translated into the Italian language in a culturally responsive manner. The total score was calculated by adding the scores on the five items. The participants were divided into two groups according to the total score (SARC-F < 4 vs. SARC-F ≥ 4), and their associations with various factors (handgrip test, chair stand test, and Skeletal Muscle Index assessed by DXA) have been examined by gender. In addition, the tool’s validity was analyzed by comparing it with different international working group diagnostic criteria for sarcopenia. Results: The total prevalence of sarcopenia according to the SARC-F was 14.2% and, specifically, 12.8% among men and 14.3% in women. The sensitivity of the SARC-F was (male (M): 11–50% and female (F): 22–36%) medium-low compared with the European, international, and Asian criteria of sarcopenia; however, SARC-F showed a high specificity (M: 77.3–100% and F: 79.5–100%) and a moderate Cronbach’s alpha coefficient of (0.669 (CI95%: 0.358–0.830). The participants in the SARC-F ≥ 4 group had poorer handgrip for EWGSOP2 (p < 0.001) and chair stand (p < 0.001) than the participants in the SARC-F < 4 group. Conclusions: The Italian language version of SARC-F showed high specificity, moderate reliability, and good associations with other predictive tests. The Italian version of SARC-F appears to be a useful screening tool for the diagnosis of sarcopenia in Italian elderly populations. 相似文献