全文获取类型
收费全文 | 3855篇 |
免费 | 233篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 41篇 |
儿科学 | 124篇 |
妇产科学 | 77篇 |
基础医学 | 379篇 |
口腔科学 | 164篇 |
临床医学 | 289篇 |
内科学 | 998篇 |
皮肤病学 | 60篇 |
神经病学 | 365篇 |
特种医学 | 97篇 |
外科学 | 716篇 |
综合类 | 25篇 |
一般理论 | 1篇 |
预防医学 | 243篇 |
眼科学 | 89篇 |
药学 | 207篇 |
中国医学 | 3篇 |
肿瘤学 | 225篇 |
出版年
2023年 | 24篇 |
2022年 | 59篇 |
2021年 | 115篇 |
2020年 | 71篇 |
2019年 | 107篇 |
2018年 | 119篇 |
2017年 | 88篇 |
2016年 | 94篇 |
2015年 | 90篇 |
2014年 | 139篇 |
2013年 | 176篇 |
2012年 | 275篇 |
2011年 | 279篇 |
2010年 | 177篇 |
2009年 | 156篇 |
2008年 | 265篇 |
2007年 | 238篇 |
2006年 | 249篇 |
2005年 | 246篇 |
2004年 | 202篇 |
2003年 | 173篇 |
2002年 | 170篇 |
2001年 | 36篇 |
2000年 | 27篇 |
1999年 | 46篇 |
1998年 | 40篇 |
1997年 | 49篇 |
1996年 | 38篇 |
1995年 | 29篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1992年 | 21篇 |
1991年 | 19篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 15篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 15篇 |
1984年 | 14篇 |
1983年 | 12篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1973年 | 9篇 |
排序方式: 共有4103条查询结果,搜索用时 15 毫秒
41.
Mauricio Sarmiento-Cobos Carlos Rivera Luis Felipe Okida Vicente J. Cogollo Lisandro Montorfano David Gutierrez Blanco Emanuele Lo Menzo Samuel Szomstein Raul J. Rosenthal 《Surgery for obesity and related diseases》2021,17(6):1140-1145
BackgroundObesity is a well-known risk factor for heart disease, resulting in a broad spectrum of cardiovascular changes. Left ventricular mass (LVM) and contractility are recognized markers of cardiac function.ObjectivesTo determine the changes of LVM and contractility after bariatric surgery (BaS).SettingUniversity hospital, United StatesMethodsTo determine the cardiac changes in ventricular mass, ventricular contractility, and left ventricular shortening fraction (LVSF), we retrospectively reviewed the 2-dimensional echocardiographic parameters of patients with obesity who underwent BaS at our institution. We compared these results before and after BaS.ResultsA total of 40 patients met the inclusion criteria. The majority were females (57.5%; n = 23), with an average age of 63.5 ± 12.1. The excess body mass index (BMI) lost at 12 months was 48.9 ± 28.9%. The percent total weight loss after BaS was 16.46 ± 9.9%. The left ventricular mass was 234.9 ± 88.1 grams before and 181.5 ± 52.7 grams after BaS (P = .002). The LVM index was 101.3 ± 38.3 g/m2 before versus 86.7 ± 26.6 g/m2 after BaS (P = .005). The LVSF was 31% ± 8.8% before and 36.3% ± 8.2% after BaS (P = .007). We found a good correlation between the decrease in LVM index and the BMI after BaS (P = .03).ConclusionRapid weight loss results in a decrease of the LVM index, as well as improvement in the left ventricular muscle contractility. Our results suggest that there is left ventricular remodeling and an improvement of heart dynamics following bariatric surgery. Further studies are needed to better assess these findings. 相似文献
42.
43.
Andrew I. Jun Wyman T. McGuirt Raul Hinojosa Glenn E. Green Nathan Fischel‐Ghodsian Richard J. H. Smith 《The Laryngoscope》2000,110(2):269-269
Objective: Mutations in GJB2, a gene that encodes a gap junction protein, Connexin 26 (Cx26), are responsible for approximately one third of sporadic severe‐to‐profound or profound congenital deafness and half of severe‐to‐profound or profound autosomal recessive nonsyndromic hearing loss (ARNSHL). Mouse mutants homozygous for knockouts of this gene are nonviable, precluding histopathologic studies of the associated inner ear pathology in this animal model. Therefore, we studied archival temporal bone sections to identify temporal bone donors with Cx26‐related deafness. Study Design: Temporal bone donors with a history of congenital severe‐to‐profound or profound deafness were identified in the registry of the Temporal Bone Library at the University of Iowa. Histological findings were interpreted in a blinded fashion. DNA extracted from two celloidin‐embedded mid‐modiolar sections from each temporal bone was screened for the 35delG Cx26 mutation. The entire coding region of Cx26 was screened for other deafness‐causing mutations if the 35delG mutation was detected. Results: Of five temporal bone donors with congenital severe‐to‐profound deafness, one donor was found to have Cx26‐related deafness. This individual was a Cx26 compound heterozygote, carrying the 35delG mutation and a noncomplementary Cx26 missense mutation on the opposing allele. Microscopic evaluation of this temporal bone showed no neural degeneration, a good population of spiral ganglion cells, near‐total degeneration of hair cells in the organ of Corti, a detached and rolled‐up tectorial membrane, agenesis of the stria vascularis, and a large cyst in the scala media in the region of the stria vascularis. Conclusion: This study is the first to report the temporal bone histopathology associated with Cx26‐related deafness. Preservation of neurons in the spiral ganglion suggests that long‐term successful habilitation with cochlear implants may be possible in persons with severe‐to‐profound or profound Cx26‐related deafness. 相似文献
44.
ZHONG Xiaoyan Sepp Kaul Astrid Eichler Gunther Bastert Department of Obstetrics Gynecology Tongji Hospital Tongji Medical University Wuhan Laboratory of Oncology Department of Obstetrics Gynaecology Univ 《华中科技大学学报(医学英德文版)》1999,19(3):181-184
RT-PCRamplificationoftumor-asso-ciated(carcinoembryonicantigen)and(or)organ-specific(cytokeratin19)mRNAhasbeenusedmainlyforthedetectionofcircu-latingtumorcellsandmicrometastasesinsolidtumors[1].Originally,theproductofamplificationwasanalyzedbygelelec… 相似文献
45.
Daher E. Cutait M.D. F.A.C.S. F.R.C.S. Raul Cutait M.D. 《World journal of surgery》1991,15(2):188-197
Chagas' disease is an endemic clinical entity caused by
Trypanosoma cruzi,a parasite that is transmitted to humans by the hematophagic Triatominae insects. It affects several million persons in Latin America, mostly in Brazil, Argentina, Chile, Paraguay, and Bolivia. Megacolon, the most common complication of intestinal trypanosomiasis, results in severe constipation, for which surgery is indicated. A variety of procedures have been proposed for the correction of this disabling condition including sigmoidectomy, abdominal rectosigmoidectomy, left colectomy, and subtotal colectomy. On long-term follow-up, however, these operations have proved to be inadequate in a significant number of cases, apparently due to preservation of the dyskinetic rectum which continues to act as a functional obstacle to the progression of the fecal bolus. On the other hand, pull-through operations, which include the removal of all or almost all of the dyskinetic rectum, or the exclusion of the rectum, as in the Duhamel-Haddad operation, have been demonstrated to be superior.
The abdominoperineal endoanal pull-through resection with delayed colorectal anastomosis and the Duhamel-Haddad operation are the most accepted procedures in Brazil and other Latin American countries; their technical details are illustrated. Functional results are satisfactory. Anal continence is normal in the vast majority of cases and sexual disturbances are rare. Routine treatment of 2 main complications—fecaloma and volvulus of the sigmoid colon—are discussed.
Resumen La enfermedad de Chagas es una entidad clínica de carácter endémico transmitida al ser humano por insectos triatomídeos. Afecta a varios millones de personas en América Latina, principalmente en Brasil, Argentina, Chile, Paraguay, y Bolivia. El megacolon es una de las complicaciones más comunes de esta enfermedad. La cirugia esta indicada en la gran mayoría de los casos y tiene como propósito principal curar el severo estreñimiento que afecta a la mayoría de los pacientes. Entre los procedimientos quirúrgicos que han sido propuestos, la sigmoidectomía, la rectosigmoidectomía abdominal, la colectomía izquierda, y la colectomía total han demostrado ser ineficaces, en un número significativo de casos, en el seguimiento a largo plazo, ciertamente porque en estos procedimientos se preserva el recto disquinético, el cual continúa actuando como un obstáculo funcional al avance del bolo fecal. Por el contrario, las operaciones de tipo pull-through han demostrado mayor efectividad, en virtud de que incluyen la resección de la totalidad o de la casi totalidad del recto disquinético, o su exclusión, como en la operación de Duhamel-Haddad. La resección abdominoperineal con pull-through endoanal y la operación de Duhamel-Haddad son los 2 procedimientos de preferencia en Brasil y en las naciones latinoamericanas. Se ilustran sus detalles técnicos. La continencia anal queda normal en la mayoría de los casos operados y la disfunción sexual es rara. Se discute el tratamiento rutinario de otras 2 complicaciones—el fecaloma y el vólvulos del sigmoide.
Résumé La maladie de Chagas est une entité clinique endémique provoquée par le Trypanosome cruzi, parasite transmis aux hommes par les insectes Triatominae hématophagi. Elle affecte plusieurs millions d'individus en Amérique Latine, surtout au Brésil, en Argentine, au Chile, au Paraguay, et au Bolivie. Le mégacôlon, complication la plus courante de la trypanosomiase intestinale se traduit par une constipation grave pour laquelle la chirurgie est indiquée. Différents procédés ont été proposés pour corriger cet état invalidant comprenant sigmoïdectomie, rectosigmoïdectomie, colectomie gauche, et colectomie subtotale. Un bon nombre de ces interventions se sont avérées inadaptées dans les suites à long terme ce qui est apparemment dû à la conservation du rectum dyskinétique qui continue à agir comme obstacle fonctionnel à la progression des selles. Par ailleurs, les interventions par retournement qui comprennent l'ablation soit totale soit subtotale du rectum dyskinétique ou son exclusion comme dans l'intervention de Duhamel-Haddad, se sont avérées meilleures. La résection abdominopérinéale par retournement avec anastomose colorectale retardée et l'intervention de Duhamel-Haddad sont les processus les plus couramment employés au Brésil et dans les autres pays d'Amérique Latine; les détails techniques sont illustrés. Les résultats fonctionnels sont satisfaisants. La continence est normale dans la plus grande majorité des cas et les troubles sexuels sont rares. Le traitement systématique des 2 complications principales, fécalome et volvulus du côlon sigmoïde, sont discutées.相似文献
46.
Anders
sterlund Raul Popa Tapio Nikkil Annika Scheynius Lars Engstrand 《The Laryngoscope》1997,107(5):640-647
Numerous theories have been presented that attempt to explain the frequent recurrences of pharyngotonsillitis caused by Streptococcus pyogenes; these recurrences occur after seemingly adequate antibiotic treatment. We previously have demonstrated that S pyogenes can survive for up to 7 days intracellularly in immortalized human respiratory epithelial cells grown in an antibiotic supplemented medium. Viable S pyogenes were externalized and established an extracellular infection, whenever the extracellular antibiotic was removed. We have investigated the presence of intracellular S pyogenes in two in vivo studies using respiratory epithelial cells collected from patients with tonsillitis and the tonsils of asymptomatic carriers. Electron microscopy and immunohistochemistry demonstrated intracellular S pyogenes in pharyngeal epithelial cells in 13 of 14 patients with tonsillitis (93%). Furthermore, intracellular S pyogenes were found in macrophage-like cells in eight (73%) and in epithelial cells in four (36%) tonsils from 11 asymptomatic S pyogenes carriers. These in vivo data strongly support the hypothesis that intracellular S pyogenes can constitute a reservoir of bacteria with the potential to cause reinfections 相似文献
47.
The objectives of this article are to describe the evidence base for alcohol policy in the Americas, to evaluate the extent to which national policies are likely to have an impact on public health, and to identify areas where alcohol policies could be improved. The paper begins with a brief review of epidemiological surveys of the prevalence of alcohol problems in the Americas. This is followed by an analysis of 32 prevention strategies and interventions in terms of the evidence for their effectiveness, amount of research support, cost to implement, and other feasibility issues. Overall, the strategies and interventions with the greatest amount of empirical support are low blood alcohol concentration levels for driving while intoxicated, controls on alcohol availability, age limits on alcohol purchases, and relatively high alcohol prices. The implications of the evidence are next discussed in relation to alcohol policy initiatives in the Americas, based on an analysis of the extent to which strategies and interventions currently used in 25 countries of the Americas are likely to have a public health impact on alcohol-related problems. The countries that have adopted the policies with the highest expected impact overall are Colombia, Costa Rica, Venezuela, and El Salvador. Nevertheless, the analysis indicates that almost all the countries of the Americas could improve the likelihood of preventing alcohol-related problems. Policy efforts in the developing countries of Latin America should focus on improving countermeasures against driving while intoxicated, measures that alter the drinking context, and limits on physical availability. For the developed, high-income countries of North America the goal should be to prevent deterioration of current drinking patterns and to reduce the overall volume of drinking. Given the low to moderate cost of many of the policies reviewed in this article, it now seems possible for communities and nations to substantially reduce the alcohol-related burden of illness in the Americas. 相似文献
48.
Alasdair M Barr Virginia Lehmann-Masten Martin Paulus Raul R Gainetdinov Marc G Caron Mark A Geyer 《Neuropsychopharmacology》2004,29(2):221-228
A hyperdopaminergic state in humans has been hypothesized to contribute to the pathology of a number of psychiatric illnesses, including schizophrenia, bipolar disorder, and attention deficit hyperactivity disorder. Mice that display elevated synaptic levels of dopamine due to a genetically engineered deletion of the dopamine transporter (DAT) model behavioral deficits that simulate the above conditions. As novel treatment strategies for these disorders have focused on the serotonin (5-HT) 2A receptor, we determined the capacity of the highly selective 5-HT(2A) receptor antagonist M100907 to reverse behavioral deficits in DAT knockout (KO) mice. Prior to drug treatment, DAT KO mice exhibited increased levels of locomotor activity and highly linearized movement in a novel environment, as well as reduced prepulse inhibition (PPI) of acoustic startle, compared to wild-type littermates. Treatment with M100907 (0.3-1.0 mg/kg, but not 0.1 mg/kg) reversed locomotor deficits in DAT KO mice. Similarly, treatment with 1.0 mg/kg M100907 reversed the PPI deficits in DAT KO mice. These data indicate that selective 5-HT(2A) receptor antagonists, such as M100907, may represent a class of drugs that can be used to treat conditions in which a chronic, elevated dopaminergic tone is present and contributes to abnormal behavior and sensorimotor gating deficits. 相似文献
49.
50.