全文获取类型
收费全文 | 6298篇 |
免费 | 326篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 127篇 |
妇产科学 | 88篇 |
基础医学 | 638篇 |
口腔科学 | 103篇 |
临床医学 | 377篇 |
内科学 | 1939篇 |
皮肤病学 | 59篇 |
神经病学 | 655篇 |
特种医学 | 169篇 |
外科学 | 791篇 |
综合类 | 40篇 |
一般理论 | 5篇 |
预防医学 | 419篇 |
眼科学 | 238篇 |
药学 | 418篇 |
1篇 | |
中国医学 | 16篇 |
肿瘤学 | 507篇 |
出版年
2023年 | 48篇 |
2022年 | 104篇 |
2021年 | 215篇 |
2020年 | 104篇 |
2019年 | 184篇 |
2018年 | 204篇 |
2017年 | 159篇 |
2016年 | 157篇 |
2015年 | 169篇 |
2014年 | 215篇 |
2013年 | 338篇 |
2012年 | 486篇 |
2011年 | 468篇 |
2010年 | 281篇 |
2009年 | 247篇 |
2008年 | 429篇 |
2007年 | 443篇 |
2006年 | 430篇 |
2005年 | 374篇 |
2004年 | 285篇 |
2003年 | 306篇 |
2002年 | 270篇 |
2001年 | 82篇 |
2000年 | 61篇 |
1999年 | 47篇 |
1998年 | 61篇 |
1997年 | 42篇 |
1996年 | 36篇 |
1995年 | 28篇 |
1994年 | 24篇 |
1993年 | 15篇 |
1992年 | 40篇 |
1991年 | 30篇 |
1990年 | 22篇 |
1989年 | 30篇 |
1988年 | 26篇 |
1987年 | 23篇 |
1986年 | 17篇 |
1985年 | 14篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 18篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 7篇 |
排序方式: 共有6654条查询结果,搜索用时 31 毫秒
51.
Mohammad Abumayyaleh Iván J. Núñez Gil Ibrahim El-Battrawy Vicente Estrada Víctor Manuel Becerra-Muñoz Alvaro Aparisi Inmaculada Fernández-Rozas Gisela Feltes Ramón Arroyo-Espliguero Daniela Trabattoni Javier López-País Martino Pepe Rodolfo Romero Diego Raúl Villavicencio García Carloalberto Biole Thamar Capel Astrua Charbel Maroun Eid Emilio Alfonso Ibrahim Akin 《Obesity research & clinical practice》2021,15(3):275-280
BackgroundObesity has been described as a protective factor in cardiovascular and other diseases being expressed as ‘obesity paradox’. However, the impact of obesity on clinical outcomes including mortality in COVID-19 has been poorly systematically investigated until now. We aimed to compare clinical outcomes among COVID-19 patients divided into three groups according to the body mass index (BMI).MethodsWe retrospectively collected data up to May 31st, 2020. 3635 patients were divided into three groups of BMI (<25 kg/m2; n = 1110, 25?30 kg/m2; n = 1464, and >30 kg/m2; n = 1061). Demographic, in-hospital complications, and predictors for mortality, respiratory insufficiency, and sepsis were analyzed.ResultsThe rate of respiratory insufficiency was more recorded in BMI 25?30 kg/m2 as compared to BMI < 25 kg/m2 (22.8% vs. 41.8%; p < 0.001), and in BMI > 30 kg/m2 than BMI < 25 kg/m2, respectively (22.8% vs. 35.4%; p < 0.001). Sepsis was more observed in BMI 25?30 kg/m2 and BMI > 30 kg/m2 as compared to BMI < 25 kg/m2, respectively (25.1% vs. 42.5%; p = 0.02) and (25.1% vs. 32.5%; p = 0.006). The mortality rate was higher in BMI 25?30 kg/m2 and BMI > 30 kg/m2 as compared to BMI < 25 kg/m2, respectively (27.2% vs. 39.2%; p = 0.31) (27.2% vs. 33.5%; p = 0.004). In the Cox multivariate analysis for mortality, BMI < 25 kg/m2 and BMI > 30 kg/m2 did not impact the mortality rate (HR 1.15, 95% CI: 0.889?1.508; p = 0.27) (HR 1.15, 95% CI: 0.893?1.479; p = 0.27). In multivariate logistic regression analyses for respiratory insufficiency and sepsis, BMI < 25 kg/m2 is determined as an independent predictor for reduction of respiratory insufficiency (OR 0.73, 95% CI: 0.538?1.004; p = 0.05).ConclusionsHOPE COVID-19-Registry revealed no evidence of obesity paradox in patients with COVID-19. However, Obesity was associated with a higher rate of respiratory insufficiency and sepsis but was not determined as an independent predictor for a high mortality. 相似文献
52.
Elena Tragni Luisella Vigna Massimiliano Ruscica Chiara Macchi Manuela Casula Alfonso Santelia Alberico L. Catapano Paolo Magni 《Nutrients》2021,13(6)
Background: The prevention and treatment of obesity and its cardio-metabolic complications are relevant issues worldwide. Among lifestyle approaches, very low-calorie ketogenic diets (VLCKD) have been shown to lead to rapid initial weight loss, resulting in better long-term weight loss maintenance. As no information on VLCKD studies carried on in a real-world setting are available, we conducted this multi-centre study in a real-world setting, aiming at assessing the efficacy and the safety of a specific multiphasic VLCKD program in women with overweight or obesity. Methods: A multi-center, prospective, uncontrolled trial was conducted in 33 outpatient women (age range 27–60 y) with overweight or obesity (BMI: 30.9 ± 2.7 kg/m2; waist circumference: 96.0 ± 9.4 cm) who started a VLCKD dietary program (duration: 24 weeks), divided into four phases. The efficacy of VLCKD was assessed by evaluating anthropometric measures and cardiometabolic markers; liver and kidney function biomarkers were assessed as safety parameters. Results: The VLCKD program resulted in a significant decrease of body weight and BMI (−14.6%) and waist circumference (−12.4%). At the end of the protocol, 33.3% of the participants reached a normal weight and the subjects in the obesity range were reduced from 70% to 16.7%. HOMA-IR was markedly reduced from 3.17 ± 2.67 to 1.73 ± 1.23 already after phase 2 and was unchanged thereafter. Systolic blood pressure decreased after phase 1 (−3.5 mmHg) and remained unchanged until the end of the program. Total and LDL cholesterol and triglycerides were significantly reduced by VLCKD along with a significant HDL cholesterol increase. Liver, kidney and thyroid function markers did not change and remained within the reference range. Conclusions: The findings of a multi-center VLCKD program conducted in a real-world setting in a cohort of overweight/obese women indicate that it is safe and effective, as it results in a major improvement of cardiometabolic parameters, thus leading to benefits that span well beyond the mere body weight/adiposity reduction. 相似文献
53.
54.
Nicholas C Harvey Eric Orwoll Timothy Kwok Magnus K Karlsson Björn E Rosengren Eva Ribom Jane A Cauley Peggy M Cawthon Kristine Ensrud Enwu Liu Alfonso J Cruz-Jentoft Roger A Fielding Cyrus Cooper John A Kanis Mattias Lorentzon Claes Ohlsson Dan Mellström Helena Johansson Eugene McCloskey 《Journal of bone and mineral research》2021,36(7):1235-1244
Dual-energy X-ray absorptiometry (DXA)-derived appendicular lean mass/height2 (ALM/ht2) is the most commonly used estimate of muscle mass in the assessment of sarcopenia, but its predictive value for fracture is substantially attenuated by femoral neck (fn) bone mineral density (BMD). We investigated predictive value of 11 sarcopenia definitions for incident fracture, independent of fnBMD, fracture risk assessment tool (FRAX®) probability, and prior falls, using an extension of Poisson regression in US, Sweden, and Hong Kong Osteoporois Fractures in Men Study (MrOS) cohorts. Definitions tested were those of Baumgartner and Delmonico (ALM/ht2 only), Morley, the International Working Group on Sarcopenia, European Working Group on Sarcopenia in Older People (EWGSOP1 and 2), Asian Working Group on Sarcopenia, Foundation for the National Institutes of Health (FNIH) 1 and 2 (using ALM/body mass index [BMI], incorporating muscle strength and/or physical performance measures plus ALM/ht2), and Sarcopenia Definitions and Outcomes Consortium (gait speed and grip strength). Associations were adjusted for age and time since baseline and reported as hazard ratio (HR) for first incident fracture, here major osteoporotic fracture (MOF; clinical vertebral, hip, distal forearm, proximal humerus). Further analyses adjusted additionally for FRAX-MOF probability (n = 7531; calculated ± fnBMD), prior falls (y/n), or fnBMD T-score. Results were synthesized by meta-analysis. In 5660 men in USA, 2764 Sweden and 1987 Hong Kong (mean ages 73.5, 75.4, and 72.4 years, respectively), sarcopenia prevalence ranged from 0.5% to 35%. Sarcopenia status, by all definitions except those of FNIH, was associated with incident MOF (HR = 1.39 to 2.07). Associations were robust to adjustment for prior falls or FRAX probability (without fnBMD); adjustment for fnBMD T-score attenuated associations. EWGSOP2 severe sarcopenia (incorporating chair stand time, gait speed, and grip strength plus ALM) was most predictive, albeit at low prevalence, and appeared only modestly influenced by inclusion of fnBMD. In conclusion, the predictive value for fracture of sarcopenia definitions based on ALM is reduced by adjustment for fnBMD but strengthened by additional inclusion of physical performance measures. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). 相似文献
55.
56.
J. Alfonso Sanchez B. Sanchis Noguera M. J. Prado Del Baño A. Sabater Pons C. Saiz Sanchez P. Cortina Greus 《European journal of epidemiology》1993,9(1):33-39
The concept of avoidable cause of death serves as the basis for measuring the quality and diversity of a health care system. In this study the authors propose a new way to use this kind of mortality by combining with the concept of life expectancy to obtain what they call life expectancy free of avoidable mortality (LEFAM).This indicator was 76.9 in 1986 in Spain while life expectancy was 75.83. If these deaths were avoidable there would be a gain of 1.09 years per person born. There is an important difference between the would-be male gain of 1.76 years and the would-be female gain of 0.6. In the ecological study, LEFAM would better explain the year to year changes of the resources in the health sector, measured in terms of the human resources (R = 0.96), the hospital beds per thousand persons (R = –0.86), and would also increase the relation with other health indicators such as infant mortality rate (R = –0.98) and mortality rate (R = 0.59) as compared with life expectancy alone. 相似文献
57.
Alfonso Lagi MD Marcello Cipriani MD Lamberto Fattorini MD Cristiano Paggetti PhD Alberto Macerata PhD 《Clinical autonomic research》1994,4(6):307-309
The arterial baroreflex was studied in subjects who had recently had an episode of vasodepressor syncope. This was determined using 2–3 mcg/kg intravenous boluses of phenylephrine and assessing the bradycardic response. The values were measured in ms/mmHg and expressed as the angular coefficient of the regression line between the increase in R—R interval on the electrocardiograph and the systolic arterial pressure. In subjects examined immediately after the vasodepressor syncope episode the bradycardic response was much more marked than in controls (p < 0.01) and in the subjects themselves 6 months after the episode, provided that they were symptom-free (p < 0.01). It is concluded that in vasodepressor syncope there is a phase in which the baroreflex is highly sensitive and that this is due not to a lowering of the stimulation threshold but to a gain in the efferent arc, which explains a vagotonic response. 相似文献
58.
p53 Accumulation Is a Prognostic Factor in Intestinal-Type Gastric Carcinoma but Not in the Diffuse Type 总被引:2,自引:0,他引:2
Roviello F Marrelli D Vindigni C De Stefano A Spina D Pinto E 《Annals of surgical oncology》1999,6(8):739-745
Background: The prognostic value of p53 nuclear accumulation in gastric cancer is still unclear, as shown by the discordant results still reported in the literature. In this study, we evaluated the correlation between p53 accumulation and long-term survival of patients resected for intestinal and diffuse-type gastric cancer.Methods: Eighty-three patients with carcinoma of the intestinal type and 53 patients with carcinoma of the diffuse type were included in the study. Immunohistochemical staining of the paraffin sections was performed by using monoclonal antibody DO1; cases were considered positive when nuclear immunostaining was observed in 10% or more of the tumor cells. Prognostic significance of different variables was investigated by univariate and multivariate analysis.Results: p53 positivity was found in 51.8% of intestinal-type and 50.9% of diffuse-type cases. No significant correlation between the rate of p53 overexpression and age, sex, tumor location, tumor size, depth of invasion, lymph node involvement, distant metastases, and surgical radicality was found in the two groups of patients. A statistically significant difference in survival rate was observed between p53-negative and p53-positive cases in the intestinal type (P < .05), confirmed by multivariate analysis (P < .005; relative risk = 3.09). On the contrary, no correlation with survival was found in diffuse-type cases according to p53 overexpression.Conclusions: These results suggest that the immunohistochemical detection of p53 accumulation is a useful indicator of poor prognosis in the intestinal but not in the diffuse type of gastric cancer, and are indicative of distinct molecular pathways and pattern of progression in the two histotypes. 相似文献
59.
Alfonso Gil R Hurtado Navarro I Espacio Casanovas A Santos Rubio G Tomás Dols S 《Gaceta sanitaria / S.E.S.P.A.S》1999,13(1):16-21
OBJECTIVE: The purpose of this study was to describe the sociodemographic and serologic profiles in a first time consultant population at the Information and AIDS Prevention Center of Valencia (Spain). In addition, the HIV infection risk factors were analyzed. METHOD: A cross-sectional study was performed on 1,573 persons who consulted during the year 1995. Sociodemographic and infection risk practices data were recorded and serologic information about HIV, HBV and HCV infection were obtained. Exact binomial method with a 95% interval confidence was used to calculate infection prevalence and the chi square test to make comparisons between qualitative variables. RESULTS: Sex distribution was 66,1% males and 31,9% females; mean age was 29,01 (SD: 9.2) years. Sexual intercourse without condom (25.2%) and parenteral drug abusers (22.6%) were the more frequent risk groups seeking consultation about HIV infection. Global HIV infection prevalence was 12.7% (95% CI= 11,2-14,5%). Among HIV seropositive patients, sexual transmission accounted for 30.8% of cases, of which 69.4% were heterosexual relations. The HIV infection prevalence for different risk groups were the following: parenteral drug abusers 36.8% (95% CI= 31,7-42%), heterosexual intercourse with an HIV-infected partner 24.1% (95% CI= 17,1-32,2%) and homosexual intercourse between men 9,5% (95% CI= 5,8-14,5%). HCV antibody prevalence for parenteral drug abusers was 81.2% (95% CI= 76,7-85,1%). Risk practices with a statistically significant association with HIV infection were: being an injecting drug abuser, as well as having an HIV infected and/or a injecting drug abuser partner. CONCLUSIONS: Drug parenteral abusers are still the target population for prevention programs. Data suggest that prevention and sexual education programs must continue. The main effort should be focused on the young population and on sexual partners of injecting drug abusers and/or HIV seropositive partners. 相似文献
60.
Elio Ricchi M.D. Salvatore Fundarò M.D. Andrea Spallanzani M.D. Alfonso Carriero M.D. Alberto Farinetti M.D. Francesco Ferrara M.D. Carlo Pezcoller M.D. 《Diseases of the colon and rectum》1996,39(3):353-357
PURPOSE: Loss of a certain amount of cutaneous tissue of the perineal region may be remedied by first intention with creation of cutaneous flaps, thus preventing second intention healing. METHODS: We present three emblematic cases in which the posterior perineal region was reconstructed by means of vertical subcutaneous pedicle flaps, subsequent to cutaneous tissue loss after surgery for extensive condilomas or neoplastic pathologies. RESULTS: Tissue loss was repaired by means of a V-Y type vertical subcutaneous pedicle flap, constructed laterally of the extirpation zone and advanced in a median direction. In all cases, no ischemia or infection of flaps occurred; sphincteral continence and long-term aesthetic results have proved to be satisfactory. CONCLUSIONS: Vertical pedicle subcutaneous flaps are well vascularized, extremely mobile, and easy to perform and have no serious postoperative complications. 相似文献