全文获取类型
收费全文 | 2677篇 |
免费 | 141篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 40篇 |
妇产科学 | 83篇 |
基础医学 | 345篇 |
口腔科学 | 177篇 |
临床医学 | 202篇 |
内科学 | 639篇 |
皮肤病学 | 106篇 |
神经病学 | 166篇 |
特种医学 | 30篇 |
外科学 | 380篇 |
综合类 | 26篇 |
预防医学 | 225篇 |
眼科学 | 36篇 |
药学 | 168篇 |
中国医学 | 14篇 |
肿瘤学 | 177篇 |
出版年
2024年 | 2篇 |
2023年 | 23篇 |
2022年 | 54篇 |
2021年 | 98篇 |
2020年 | 48篇 |
2019年 | 70篇 |
2018年 | 86篇 |
2017年 | 68篇 |
2016年 | 48篇 |
2015年 | 75篇 |
2014年 | 126篇 |
2013年 | 119篇 |
2012年 | 225篇 |
2011年 | 234篇 |
2010年 | 135篇 |
2009年 | 113篇 |
2008年 | 210篇 |
2007年 | 197篇 |
2006年 | 165篇 |
2005年 | 145篇 |
2004年 | 162篇 |
2003年 | 123篇 |
2002年 | 126篇 |
2001年 | 16篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 14篇 |
1997年 | 27篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1976年 | 4篇 |
1973年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1944年 | 2篇 |
1934年 | 1篇 |
排序方式: 共有2842条查询结果,搜索用时 15 毫秒
191.
Body Mass Index and the Prevalence of Metabolic Syndrome among Children and Adolescents in Two Mexican Populations 总被引:2,自引:0,他引:2
Elizabeth Halley Castillo M.Sc. Guilherme Borges Dr.Sc. Juan O. Talavera M.Sc. Ricardo Orozco B.A. Claudia Vargas-Alemn B.A. Gerardo Huitrn-Bravo M.C. Juan Carlos Diaz-Montiel M.Sc. Susana Castan M.Sc. Jorge Salmern Dr.Sc. 《The Journal of adolescent health》2007,40(6):521-526
PurposeTo report the prevalence of metabolic syndrome (MS) among children and adolescents living in central Mexico, and its association with body mass index (BMI).MethodsIn a sample of 1366 subjects from 7 to 24-years-old, a self-administered questionnaire was used to determined demographic characteristics. The definition of pediatric MS was determined using analogous criteria to Adult Treatment Panel III (ATPIII) as ≥ 3 of the following: concentration of triglycerides ≥ 100 mg/dL, HDL cholesterol < 45 mg/dL for males and < 50 mg/dL for females, waist circumference ≥ 75th percentile (sex specific), glucose concentration ≥ 110 to < 126 mg/dL, and systolic or diastolic blood pressure ≥ 90th percentile (age, height, and sex specific).ResultsMost of the sample was in the 10–14- (32.4%) and the 15–19-year (35.4%) age groups, mostly females (57%), and 31% of this young sample was overweight (mean BMI = 21.6 kg/m2). About 1 in every 5 participants had full criteria for MS (19.2%, 95% confidence interval [CI]: 16.4–22.1 among females, and 20.2%, 95% CI: 17.1–23.7 among males), and only 1 in every 10 was free of any MS component. The most common component was a low HDL level, observed in 85.4% of the sample. Unfavorable fat distribution, as indicated by a large waist circumference, was present in 27.9% of the sample. About 66% of those 10–14-year-olds with a large BMI were positive for MS.ConclusionsMS and overweight are major problems for youth in Mexico. Immediate and comprehensive actions at home and schools are needed if Mexico wants to avoid the heavy burden that this disorder will have for its population in the near future. 相似文献
192.
Juana Sánchez Luis Orozco Jefferson Buendía Gerardo Mu?oz 《Pan American journal of public health》2007,21(6):335-344
OBJECTIVE: To validate a method for the presumptive diagnosis of cutaneous leishmaniasis based on the observation of clinical-epidemiological criteria, carried out by community health workers in three endemic municipalities in Santander, a department in northeastern Colombia. METHODS: This evaluation study of diagnostic technologies was based on a cross-sectional sampling of suspected cases of cutaneous leishmaniasis in the municipalities of Rionegro, El Playón, and Landázuri. After being trained, the community health workers carried out the presumptive diagnoses of cutaneous leishmaniasis between October 2004 and November 2005. At the time of diagnosis, the health workers also collected samples for confirmatory diagnosis through Field's stain method, culturing, and polymerase chain reaction. Four criteria were used to assess the validity of the presumptive diagnoses carried out by the health workers: sensitivity, specificity, positive predictive value, and negative predictive value. Replicability among the health workers was estimated through their observed level of agreement. RESULTS: According to the laboratory tests, of the 196 patients studied, 33 (16.8%) were negative and 163 (83.2%) were positive. For all the levels of certainty of the clinical diagnosis, the sensitivity was between 52% and 98% (kappa(1, 0) = 39.0%) and the specificity between 9% and 55% (kappa(0, 0) = 14.0%). The area under the receiver operating characteristic curve was 56.5% (95% confidence interval: 45.6% to 67.4%). The proportion of positive agreement and of negative agreement was 86.3% and 43.5%, respectively. CONCLUSIONS: The sensitivity of the presumptive diagnosis carried out by the health workers surpasses that of the parasitological diagnostic methods generally used in the three endemic areas, but its specificity is much lower. Even though this approach is not useful as a diagnostic test for cutaneous leishmaniasis or as a criterion for deciding to proceed with treatment or not, the method is useful for the active identification of cases in the community. 相似文献
193.
Urinary tract infections during pregnancy 总被引:2,自引:0,他引:2
OBJECTIVE: To provide a comprehensive review of urinary tract infections (UTIs) during pregnancy. All aspects of UTIs, including epidemiology, pathogenesis, resistance, clinical features, diagnosis, treatment, and prevention, were reviewed. DATA SOURCES: MEDLINE (1966-August 2003) and Cochrane Library searches were performed using the key search terms urinary tract infection, pyelonephritis, cystitis, asymptomatic bacteriuria, and resistance. STUDY SELECTION AND DATA EXTRACTION: All article abstracts were evaluated for relevance. Only articles pertaining to pregnancy were included. The majority of published literature were review articles; the number of original clinical studies was limited. DATA SYNTHESIS: UTIs are the most common bacterial infections during pregnancy. They are characterized by the presence of significant bacteria anywhere along the urinary tract. Pyelonephritis is the most common severe bacterial infection that can lead to perinatal and maternal complications including premature delivery, infants with low birth weight, fetal mortality, preeclampsia, pregnancy-induced hypertension, anemia, thrombocytopenia, and transient renal insufficiency. Enterobacteriaceae account for 90% of UTIs. The common antibiotics used are nitrofurantoin, cefazolin, cephalexin, ceftriaxone, and gentamicin. CONCLUSIONS: Therapeutic management of UTIs in pregnancy requires proper diagnostic workup and thorough understanding of antimicrobial agents to optimize maternal outcome, ensure safety to the fetus, and prevent complications that lead to significant morbidity and mortality in both the fetus and the mother. 相似文献
194.
Silvestri I Longanesi Cattani I Franco P Pirozzi G Botti G Stoppelli MP Carriero MV 《International journal of cancer. Journal international du cancer》2002,102(6):562-571
We have previously shown that urokinase receptor physically and functionally interacts with alpha(v)beta5 vitronectin receptor, leading to tumor breast cell migration and invasion. Here, the link between these 2 receptors was further investigated by analyzing the expression levels of urokinase receptor and alpha(v)beta5 integrin in 35 human breast carcinomas and 5 benign breast lesions. The occurrence of a positive correlation between urokinase receptor and alpha(v)beta5 protein levels in benign and malignant tumor specimens prompted us to investigate whether engaged urokinase receptors might modulate alpha(v)beta5 expression. Here, we report the receptor-dependent ability of catalytically inactive urokinase to upregulate the alpha(v) and beta5 chains in MDA-MB-231 and MCF-7 breast carcinoma cell lines in a time- and concentration-dependent manner. This effect is dependent on protein kinase C activity and requires new protein synthesis. Accordingly, the availability of assembled alpha(v)beta5 receptors on the cell surface increases upon urokinase treatment, as shown by immunoprecipitation and immunocytochemical analyses. Exposure to urokinase leads to enhanced tumor cell migration and invasion, which is prevented by the "phosphorylation-like" urokinase receptor antagonist His-uPA(138E/303E), the DNA-binding drug mithramycin, the protein kinase C inhibitor calphostin C and anti-alpha(v)beta5 antibodies. Finally, urokinase enables benign breast MCF-10A cells to cross Matrigel in a alpha(v)beta5- and urokinase receptor-dependent manner, indicating that urokinase controls a regulatory circuitry crucial to breast tumor progression. 相似文献
195.
The thick ascending limb of Henle’s loop is a nephron segment that is vital to the formation of dilute and concentrated urine.
This ability is accomplished by a consortium of functionally coupled proteins consisting of the apical Na+:K+:2Cl− co-transporter, the K+ channel, and basolateral Cl− channel that mediate electroneutral salt absorption. In thick ascending limbs, salt absorption is importantly regulated by
the calcium-sensing receptor. Genetic or pharmacological disruption impairing the function of any of these proteins results
in Bartter syndrome. The thick ascending limb is also an important site of Ca2+ and Mg2+ absorption. Calcium-sensing receptor activation inhibits cellular Ca2+ absorption induced by parathyroid hormone, as well as passive paracellular Ca2+ transport. The present review discusses these functions and their genetic and molecular regulation.
相似文献
Peter A. FriedmanEmail: |
196.
Jorge Ramón Padilla-Gutiérrez Claudia Azucena Palafox-Sánchez Yeminia Valle Gerardo Orozco-Barocio Edith Oregón-Romero Mónica Vázquez-Del Mercado Héctor Rangel-Villalobos Mara Anaís Llamas-Covarrubias José Francisco Mu?oz-Valle 《Clinical and experimental medicine》2011,11(1):11-17
Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the presence of autoantibodies against
nuclear autoantigens as well as cytoplasmic and circulating proteins. Recent studies have demonstrated mechanisms responsible
for modulation of the immune response by the plasminogen activator inhibitor-1 (PAI-1). Furthermore, the endogenous PAI-1
has shown to promote a Th2 immune response. We assessed the −844 G>A and HindIII C>G PAI-1 polymorphisms in SLE. In a case–control study of 71 SLE patients classified according to ACR criteria and 71 healthy subjects
(HS). The A allele of −844 PAI-1 polymorphism showed a significant difference in SLE patients (41%) when compared with HS (27%) [P = 0.01; OR = 1.8, 95%, CI = 1.1–3.0]. In addition, the −844 G>A PAI-1 polymorphism was associated with increased risk for SLE in a dominant genetic model (G/G vs. G/A + A/A; OR = 2.3, 95% CI = 1.14–4.44).
Also, anti-RNP positive antibodies in SLE were associated with G/G −844 PAI-1 genotype. The HindIII polymorphism did not show any differences. The haplotype analysis showed that the AC haplotype confers susceptibility
to SLE (OR = 3.1, 95% CI, 1.45–6.52; P = 0.003). The AC haplotype of the −844 and HindIII PAI-1 polymorphism might be an additional susceptibility factor to SLE in Mexicans. 相似文献
197.
Octavio Campollo Gerardo Amaya P Aiden McCormick 《World journal of gastroenterology : WJG》2022,28(37):5395-5402
The discovery of hepatitis C has been a landmark in public health as it brought the opportunity to save millions of lives through the diagnosis, prevention and cure of the disease. The combined work of three researchers, Alter H, Houghton M and Rice C, which set the basis for the diagnosis, treatment and prevention of hepatitis C apart from laying the ground work for a new approach to study infections in general and developing new antiviral agents. This is a story of a transfusion-associated infection. A series of clinical studies demonstrated the existence of an infectious agent associated with hepatitis. That was followed by the identification of what was later known to be the hepatitis C virus (HCV) and the development of diagnostic tests. It all preceded the full molecular identification and demonstration of a causal effect. Finally it ended up with the development and discovery of a new class of therapeutic drugs, the direct acting antivirals, which are now used not only to cure the disease but most probably, to eliminate the problem. This work started with Dr Alter H who demonstrated that a new virus was responsible for the majority of post-transfusion hepatitis followed by Houghton M who cloned the virus and developed the blood test to identify those cases that carried the virus. Finally, the work of Rice C demonstrated that a cloned HCV produced after applying molecular biology techniques could cause long-standing infection and cause the same disease as the one observed in humans. 相似文献
198.
Seewald S Brand B Groth S Omar S Mendoza G Seitz U Yasuda I Xikun H Nam VC Xu H Thonke F Soehendra N 《Gastrointestinal endoscopy》2004,59(4):463-470
BACKGROUND: The treatment of pancreatic fistula can be difficult. A novel endoscopic approach to sealing pancreatic fistulas by using N-butyl-2-cyanoacrylate is described. METHODS: Twelve patients with pancreatic fistulas underwent endoscopic injection of N-butyl-2-cyanoacrylate into the fistulous tract, in addition to endoscopic drainage. RESULTS: Fistulas were closed successfully in 8 of 12 patients. A single treatment session was successful in 7 patients; a second session was required in one patient. In two patients, closure was temporary, and, in one patient, the treatment failed. One patient died 24 hours after treatment. He developed a pulmonary thromboembolism from a left popliteal vein thrombosis and died from complications of surgical thromboembolectomy. At autopsy, a pulmonary embolus was found, but there was no evidence of N-butyl-2-cyanoacrylate in the lungs. No procedure-related complication occurred over a median follow-up of 20.7 months (range 9-51 months). CONCLUSIONS: In this preliminary study, occlusion of pancreatic fistulas by using N-butyl-2-cyanoacrylate glue was safe and effective, and obviated the need for surgery in a substantial proportion of patients. Further studies of the use of N-butyl-2-cyanoacrylate for closure of pancreatic fistula are warranted. 相似文献
199.
Jesús Sotomayor-Bonilla Andrea Chaves Oscar Rico-Chávez Melinda K. Rostal Rafael Ojeda-Flores Mónica Salas-Rojas álvaro Aguilar-Setien Sergio Ibá?ez-Bernal Arturo Barbachano-Guerrero Gustavo Gutiérrez-Espeleta J. Leopoldo Aguilar-Faisal A. Alonso Aguirre Peter Daszak Gerardo Suzán 《The American journal of tropical medicine and hygiene》2014,91(1):129-131
200.
Supplemental perioperative oxygen and the risk of surgical wound infection: a randomized controlled trial 总被引:13,自引:0,他引:13
Belda FJ Aguilera L García de la Asunción J Alberti J Vicente R Ferrándiz L Rodríguez R Company R Sessler DI Aguilar G Botello SG Ortí R;Spanish Reduccion de la Tasa de Infeccion Quirurgica Group 《JAMA》2005,294(16):2035-2042
Context Supplemental perioperative oxygen has been variously reported to halve or double the risk of surgical wound infection. Objective To test the hypothesis that supplemental oxygen reduces infection risk in patients following colorectal surgery. Design, Setting, and Patients A double-blind, randomized controlled trial of 300 patients aged 18 to 80 years who underwent elective colorectal surgery in 14 Spanish hospitals from March 1, 2003, to October 31, 2004. Wound infections were diagnosed by blinded investigators using Centers for Disease Control and Prevention criteria. Baseline patient characteristics, anesthetic treatment, and potential confounding factors were recorded. Interventions Patients were randomly assigned to either 30% or 80% fraction of inspired oxygen (FIO2) intraoperatively and for 6 hours after surgery. Anesthetic treatment and antibiotic administration were standardized. Main Outcome Measures Any surgical site infection (SSI); secondary outcomes included return of bowel function and ability to tolerate solid food, ambulation, suture removal, and duration of hospitalization. Results A total of 143 patients received 30% perioperative oxygen and 148 received 80% perioperative oxygen. Surgical site infection occurred in 35 patients (24.4%) administered 30% FIO2 and in 22 patients (14.9%) administered 80% FIO2 (P=.04). The risk of SSI was 39% lower in the 80% FIO2 group (relative risk [RR], 0.61; 95% confidence interval [CI], 0.38-0.98) vs the 30% FIO2 group. After adjustment for important covariates, the RR of infection in patients administered supplemental oxygen was 0.46 (95% CI, 0.22-0.95; P = .04). None of the secondary outcomes varied significantly between the 2 treatment groups. Conclusions Patients receiving supplemental inspired oxygen had a significant reduction in the risk of wound infection. Supplemental oxygen appears to be an effective intervention to reduce SSI in patients undergoing colon or rectal surgery. Trial Registration ClinicalTrials.gov Identifier: NCT00235456 相似文献