全文获取类型
收费全文 | 11418篇 |
免费 | 654篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 190篇 |
儿科学 | 168篇 |
妇产科学 | 200篇 |
基础医学 | 1722篇 |
口腔科学 | 1028篇 |
临床医学 | 938篇 |
内科学 | 2604篇 |
皮肤病学 | 250篇 |
神经病学 | 760篇 |
特种医学 | 205篇 |
外科学 | 1345篇 |
综合类 | 36篇 |
一般理论 | 5篇 |
预防医学 | 1178篇 |
眼科学 | 117篇 |
药学 | 883篇 |
中国医学 | 146篇 |
肿瘤学 | 351篇 |
出版年
2023年 | 137篇 |
2022年 | 236篇 |
2021年 | 453篇 |
2020年 | 292篇 |
2019年 | 382篇 |
2018年 | 479篇 |
2017年 | 321篇 |
2016年 | 342篇 |
2015年 | 398篇 |
2014年 | 517篇 |
2013年 | 678篇 |
2012年 | 942篇 |
2011年 | 1091篇 |
2010年 | 510篇 |
2009年 | 411篇 |
2008年 | 651篇 |
2007年 | 669篇 |
2006年 | 574篇 |
2005年 | 493篇 |
2004年 | 395篇 |
2003年 | 333篇 |
2002年 | 331篇 |
2001年 | 211篇 |
2000年 | 211篇 |
1999年 | 167篇 |
1998年 | 44篇 |
1997年 | 43篇 |
1996年 | 23篇 |
1995年 | 29篇 |
1994年 | 37篇 |
1993年 | 23篇 |
1992年 | 89篇 |
1991年 | 55篇 |
1990年 | 60篇 |
1989年 | 53篇 |
1988年 | 37篇 |
1987年 | 27篇 |
1986年 | 28篇 |
1985年 | 31篇 |
1984年 | 21篇 |
1980年 | 17篇 |
1979年 | 15篇 |
1978年 | 22篇 |
1975年 | 17篇 |
1974年 | 15篇 |
1973年 | 22篇 |
1971年 | 22篇 |
1970年 | 17篇 |
1969年 | 18篇 |
1967年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Vera Maria Cury Salemi Fabio Fernandes Raquel Sirvente Luciano Nastari Leonardo Vieira Rosa Cristiano A. Ferreira José Luiz Barros Pena Michael H. Picard Charles Mady 《Clinics (S?o Paulo, Brazil)》2009,64(1):17-22
OBJECTIVES:
We compared left ventricular regional wall motion, the global left ventricular ejection fraction, and the New York Heart Association functional class pre- and postoperatively.INTRODUCTION:
Endomyocardial fibrosis is characterized by fibrous tissue deposition in the endomyocardium of the apex and/or inflow tract of one or both ventricles. Although left ventricular global systolic function is preserved, patients exhibit wall motion abnormalities in the apical and inferoapical regions. Fibrous tissue resection in New York Heart Association FC III and IV endomyocardial fibrosis patients has been shown to decrease morbidity and mortality.METHODS:
We prospectively studied 30 patients (20 female, 30±10 years) before and 5±8 months after surgery. The left ventricular ejection fraction was determined using the area-length method. Regional left ventricular motion was measured by the centerline method. Five left ventricular segments were analyzed pre- and postoperatively. Abnormality was expressed in units of standard deviation from the mean motion in a normal reference population.RESULTS:
Left ventricular wall motion in the five regions did not differ between pre- and postoperative measurements. Additionally, the left ventricular ejection fraction did not change after surgery (0.45±0.13% x 0.43±0.12% pre- and postoperatively, respectively). The New York Heart Association functional class improved to class I in 40% and class II in 43% of patients postoperatively (p<0.05).CONCLUSIONS:
Although endomyocardial fibrosis patients have improved clinical symptoms after surgery, the global left ventricular ejection fraction and regional wall motion in these patients do not change. This finding suggests that other explanations, such as improvements in diastolic function, may be operational. 相似文献992.
Ricardo Tedeschi Matos Rodrigo Schuler Honório Elia Garcia Caldini Claudio Lyoiti Hashimoto Marcelo Alves Ferreira Tomás Navarro-Rodriguez 《Clinics (S?o Paulo, Brazil)》2009,64(7):669-674
ABSTRACT:
The purpose of this study was to compare esophageal infusion with 0.1 N hydrochloridric acid (HCl) to esophageal infusion with saline in patients presenting with typical gastroesophageal reflux symptoms and erosive esophagitis.METHODS:
Upper gastrointestinal endoscopy was performed on 44 prospective subjects, 29 of whom were included in the study. Eighteen patients presented with normal esophagi (Control Group “C”), nine of whom were infused with HCl and nine with saline. Eleven patients presented with erosive esophagitis (Lesion Group “L”), five of whom were infused with HCl and six with saline. Biopsies of the esophageal mucosa were collected before and after infusions.RESULTS:
No statistically significant difference was found between the two types of infusions in terms of the dilation of the intercellular space of the esophageal epithelium, regardless of the status of the patient.CONCLUSIONS:
Response to HCl infusion cannot be used as a marker for gastroesophageal reflux disease. 相似文献993.
Adriano Meneghini Celso Ferreira Luiz Carlos de Abreu Vitor E. Valenti Marcelo Ferreira Celso F. Filho Neif Murad 《Clinics (S?o Paulo, Brazil)》2009,64(9):921-926
OBJECTIVES
Memantine is an N-methyl-d-aspartate (NMDA) glutamate receptor antagonist used to treat Alzheimer’s disease. Previous studies have suggested that receptor blockers act as neuroprotective agents; however, no study has specifically investigated the impact that these drugs have on the heart. We sought to evaluate the effects of memantine on nuclear size reduction in cardiac cells exposed to cold stress.METHOD
We used male EPM-Wistar rats (n=40) divided into 4 groups: 1) Matched control (CON); 2) Memantine-treated rats (MEM); 3) Rats undergoing induced hypothermia (IH) and 4) Rats undergoing induced hypothermia that were also treated with memantine (IHM). Animals in the MEM and IHM groups were treated by oral gavage administration of 20 mg/kg/day memantine over an eight-day period. Animals in the IH and IHM groups were submitted to 4 hours of hypothermia in a controlled environment with a temperature of − 8°C on the last day of the study.RESULTS
The MEM group had the largest cardiomyocyte nuclear size (151 ± 3.5 μm3 vs. CON: 142 ± 2.3 μm3; p<0.05), while the IH group had the smallest mean value of nuclear size. The nuclear size of the IHM group was preserved (125 ± 2.9 μm3) compared to the IH group (108 ± 1.7 μm3; p<0.05).CONCLUSION
Memantine prevented the nuclear size reduction of cardiomyocytes in rats exposed to cold stress. 相似文献994.
Samuel Aguiar Junior Fábio de Oliveira Ferreira ; Benedito Mauro Rossi érika Maria Monteiro Santos Jo?o Victor Salvajoli Ademar Lopes 《Clinics (S?o Paulo, Brazil)》2009,64(11):1059-1064
INTRODUCTION AND OBJECTIVE
Neoadjuvant and adjuvant therapies for soft tissue sarcomas of the extremities are still controversial. The aim of this study was to analyze the results of a protocol of neoadjuvant chemoradiation therapy for extremity sarcomas.METHODS
A retrospective analysis was carried out in a consecutive series of 49 adult patients with advanced extremity soft tissue sarcomas that could not be resected with adequate margins during the primary resection. All patients were treated with a protocol of preoperative radiation therapy at a total dose of 30 Gy, concomitant with doxorubicin (60 mg/m2) chemotherapy. The main endpoints assessed were local recurrence-free survival, metastasis-free survival and overall survival. The median follow-up time was 32.1 months.RESULTS
The five-year local recurrence-free survival, metastasis-free survival and overall survival rates were 81.5%, 46.7% and 58.3%, respectively. For high-grade tumors, the five-year metastasis-free and overall survival rates were only 36.3% and 41.2%, respectively. Severe wound complications were observed in 41.8% of the patients who underwent surgery. These complications precluded adjuvant chemotherapy in 73.7% (14/19) of the patients eligible to receive it.CONCLUSIONS
In this study, neoadjuvant chemoradiation therapy was associated with a good local control rate, but the distant relapse-free rate and overall survival rate were still poor. The high rate of wound complications modified the planning of adjuvant treatment in most patients. 相似文献995.
Lúcia Inês Macedo-Souza Fernando Kok † Silvana Santos Luciana Licinio Karina Lezirovitz Natale Cavaçana Clarissa Bueno Simone Amorim ré Pessoa Zodja Graciani Áurea Ferreira Abdísio Prazeres Áurea Nogueira de Melo Paulo Alberto Otto Mayana Zatz 《Annals of human genetics》2009,73(3):382-387
SPOAN is an autosomal recessive neurodegenerative disorder which was recently characterized by our group in a large inbred Brazilian family with 25 affected individuals. This condition is clinically defined by: 1. congenital optic atrophy; 2. progressive spastic paraplegia with onset in infancy; and 3. progressive motor and sensory axonal neuropathy. Overall, we are now aware of 68 SPOAN patients (45 females and 23 males, with age ranging from 5 to 72 years), 44 of which are presented here for the first time. They were all born in the same geographic micro region. Those 68 patients belong to 43 sibships, 40 of which exhibit parental consanguinity. Sixty-one patients were fully clinically evaluated and 64 were included in the genetic investigation. All molecularly studied patients are homozygotes for D11S1889 at 11q13. This enabled us to reduce the critical region for the SPOAN gene from 4.8 to 2.3 Mb, with a maximum two point lod score of 33.2 (with marker D11S987) and of 27.0 (with marker D11S1889). Three genes located in this newly defined critical region were sequenced, but no pathogenic mutation was detected. The gene responsible for SPOAN remains elusive. 相似文献
996.
Marcelo C. Leal Sérgio V. B. Pinheiro erson J. Ferreira Robson A. S. Santos Leonardo S. Bordoni Natalia Alenina Michael Bader Luiz R. França 《Journal of anatomy》2009,214(5):736-743
Evidence regarding the components of the renin–angiotensin (Ang) system suggests that this system plays an important role in male reproduction. However, there are few data available in the literature on the effects of Ang-(1–7) on the male reproductive system. The present study investigated the effects of the genetic deletion and chronic blockage of Ang-(1–7) receptor Mas on spermatogenesis and male fertility. The localization of Mas in mouse and rat testes was determined by binding assays and immunofluorescence, whereas the testis structure and spermatogenic process were morphologically and stereologically analysed by light microscopy. Ang-(1–7) binding and immunofluorescence revealed the presence of Mas in the testes of mice and rats. Although the total numbers of Sertoli and Leydig cells per testis and Leydig cell size were similar in both wild-type and Mas -deficient mice, Mas −/– animals exhibited a significant reduction in testis weight and a greater volume of apoptotic cells, giant cells and vacuoles in the seminiferous epithelium. In both mice and rats, an increased number of apoptotic cells were found during meiosis. Due to disturbed spermatogenesis, daily sperm production was markedly reduced in Mas −/– mice. Moreover, chronic infusion of A-779 [an Ang-(1–7) antagonist] in rats significantly increased the total number of apoptotic cells and primary spermatocytes in particular stages of spermatogenesis. Taken together, these findings strongly suggest that Ang-(1–7) receptor Mas plays an important role in the regulation of spermatogenesis. 相似文献
997.
Barreto do Carmo MB Neves Santos D Alves Ferreira Amorim LD Fiaccone RL Souza da Cunha S Cunha Rodrigues L Barreto ML 《Social psychiatry and psychiatric epidemiology》2009,44(5):416-420
Objective
Recent studies have shown that asthma represents a major health issue not only in children of developed countries but also in urban centers in some middle-income countries. Brazil has one of the highest prevalences of asthma worldwide. Recently, interest has grown in the relationship between psychosocial factors and asthma. This article examines the relationship between maternal mental disorders and the prevalence of asthma in low-income children from an inner city area of Salvador in the state of Bahia, Brazil, and is part of the SCAALA program (Social Change, Allergy and Asthma in Latin America). 相似文献998.
999.
IntroductionThe Sleep Disturbance Scale for Children (SDSC) is a 26-item instrument for evaluating sleep among children aged 3–18 years. It differentiates among conditions such as disorders of initiating and maintaining sleep, sleep breathing disorders, disorders of arousal, sleep–wake transition disorders, excessive somnolence, and sleep hyperhydrosis. The aim of this study was to translate, culturally adapt, and validate it for Brazilian Portuguese.MethodThe study was carried out in two phases: (1) forward translation, back translation, pretesting, and calculation of sample size; (2) validation: reliability (Chronbach’s alpha), convergent analysis (Pearson correlation), and discriminatory validity (comparing the scores of the test with the results of polysomnography). One hundred children, aged 3–18 years, accompanied by their parents and/or guardians participated in the phases. PSG studies have been done to calculate the sample size and validation.ResultsThe scale instructions and items were adapted regarding semantic, experiential, conceptual, and cultural equivalence validation. The scale structure related to visual communication was also adapted to Brazilian population preference and habits, and this resulted in a chart with clear instructions and easy recognition of the statements and possible responses. Reliability analysis showed values greater than 0.55. There has been reasonable convergent validity. Discriminatory validity using the PSG study for positive sleep-disordered breathing (SDB) was 8.9, attesting discriminatory validity only for SDB. The three questions of the scale can screen SDB.ConclusionThe SDSC was translated, adapted and validated for Brazilian Portuguese, and it presented internal consistency and convergent and discriminatory validity. It can be used in population-based studies in order to screen for sleep-disordered breathing in children. 相似文献
1000.
Mirian Salvadori Bittar Guaranha Patrícia da Silva Sousa Gerardo Maria de Araújo-Filho Katia Lin Laura Maria Figueiredo Ferreira Guilhoto Luís Otávio Sales Ferreira Caboclo Elza Márcia Targas Yacubian 《Epilepsia》2009,50(11):2446-2455
Purpose: Studies suggest that higher cognitive functions could precipitate seizures in juvenile myoclonic epilepsy (JME). The present study aimed to analyze the effects of higher mental activity on epileptiform discharges and seizures in patients with JME and compare them to those of habitual methods of activation.
Methods: Seventy-six patients with JME (41 female) underwent a video-EEG (electroencephalography) neuropsychologic protocol (VNPP) and habitual methods of activation for 4–6 h.
Results: Twenty-nine of the 76 (38.2%) presented provocative effect, and inhibition was seen in 28 of 31 (90.3%). A mixed effect was observed in 11 (35.5%), and 30 patients (39.5%) suffered no effect of VNPP. Action-programming tasks were more effective than thinking in provoking epileptiform discharges (23.7% and 11.0% of patients, respectively, p = 0.03). Inhibitory effect was observed equally in the various categories of tasks, except in mental calculation, which had a higher inhibitory rate. Habitual methods of activation were more effective than VNPP in provoking discharges. Anxiety disorders were diagnosed in 24 of 58 patients (41.4%); anxious patients had greater discharge indexes and no significant inhibitory effect on VNPP.
Discussion: Praxis exerted the most remarkable provocative effect, in accordance with the motor circuitry hyperexcitability hypothesis in JME. Inhibitory effect, which had no such task specificity, might be mediated by a widespread cortical–thalamic pathway, possibly involving the parietal cortex. The frequent inhibitory effect found under cortical activation conditions, influenced by the presence of anxiety, supports nonpharmacologic therapeutic interventions in JME. 相似文献
Methods: Seventy-six patients with JME (41 female) underwent a video-EEG (electroencephalography) neuropsychologic protocol (VNPP) and habitual methods of activation for 4–6 h.
Results: Twenty-nine of the 76 (38.2%) presented provocative effect, and inhibition was seen in 28 of 31 (90.3%). A mixed effect was observed in 11 (35.5%), and 30 patients (39.5%) suffered no effect of VNPP. Action-programming tasks were more effective than thinking in provoking epileptiform discharges (23.7% and 11.0% of patients, respectively, p = 0.03). Inhibitory effect was observed equally in the various categories of tasks, except in mental calculation, which had a higher inhibitory rate. Habitual methods of activation were more effective than VNPP in provoking discharges. Anxiety disorders were diagnosed in 24 of 58 patients (41.4%); anxious patients had greater discharge indexes and no significant inhibitory effect on VNPP.
Discussion: Praxis exerted the most remarkable provocative effect, in accordance with the motor circuitry hyperexcitability hypothesis in JME. Inhibitory effect, which had no such task specificity, might be mediated by a widespread cortical–thalamic pathway, possibly involving the parietal cortex. The frequent inhibitory effect found under cortical activation conditions, influenced by the presence of anxiety, supports nonpharmacologic therapeutic interventions in JME. 相似文献