全文获取类型
收费全文 | 9138篇 |
免费 | 705篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 441篇 |
妇产科学 | 131篇 |
基础医学 | 1152篇 |
口腔科学 | 293篇 |
临床医学 | 702篇 |
内科学 | 2536篇 |
皮肤病学 | 302篇 |
神经病学 | 572篇 |
特种医学 | 332篇 |
外国民族医学 | 2篇 |
外科学 | 1257篇 |
综合类 | 79篇 |
一般理论 | 14篇 |
预防医学 | 796篇 |
眼科学 | 135篇 |
药学 | 493篇 |
中国医学 | 35篇 |
肿瘤学 | 501篇 |
出版年
2023年 | 45篇 |
2022年 | 117篇 |
2021年 | 244篇 |
2020年 | 116篇 |
2019年 | 252篇 |
2018年 | 327篇 |
2017年 | 214篇 |
2016年 | 197篇 |
2015年 | 230篇 |
2014年 | 318篇 |
2013年 | 405篇 |
2012年 | 542篇 |
2011年 | 614篇 |
2010年 | 364篇 |
2009年 | 324篇 |
2008年 | 469篇 |
2007年 | 485篇 |
2006年 | 423篇 |
2005年 | 452篇 |
2004年 | 364篇 |
2003年 | 409篇 |
2002年 | 389篇 |
2001年 | 301篇 |
2000年 | 334篇 |
1999年 | 241篇 |
1998年 | 111篇 |
1997年 | 95篇 |
1996年 | 95篇 |
1995年 | 85篇 |
1994年 | 68篇 |
1993年 | 48篇 |
1992年 | 143篇 |
1991年 | 119篇 |
1990年 | 93篇 |
1989年 | 100篇 |
1988年 | 92篇 |
1987年 | 84篇 |
1986年 | 77篇 |
1985年 | 74篇 |
1984年 | 53篇 |
1983年 | 42篇 |
1982年 | 22篇 |
1981年 | 30篇 |
1980年 | 28篇 |
1979年 | 26篇 |
1978年 | 22篇 |
1977年 | 23篇 |
1976年 | 21篇 |
1975年 | 18篇 |
1973年 | 18篇 |
排序方式: 共有9870条查询结果,搜索用时 0 毫秒
1.
Francisca Morgado Mariana Batista Ana Moreno Inês Coutinho 《Pediatric dermatology》2021,38(1):191-193
We present a 6‐year‐old girl with skin hyperpigmentation, leukoplakia, and onychodystrophy, the classic mucocutaneous triad usually associated with dyskeratosis congenita. The patient also had premature graying of the hair, bone marrow failure, hepatitis, exudative retinopathy, osteopenia with multiple long bone fractures, and intracranial calcifications and brain cysts. Coats plus syndrome is a rare disease with a clinical and genetic overlap with dyskeratosis congenita. This disease is reviewed, with a focus on the pathogenesis of the genetic anomalies and its background as a telomere biology disorder. 相似文献
2.
Maria Gonzalez-Cao Cristina Carrera Juan Francisco Rodriguez Moreno Pedro Rodríguez-Jiménez Mónica Antoñanzas Basa Rosa Feltes Ochoa Teresa Puertolas Eva Muñoz-Couselo José Luis Manzano Ivan Marquez-Rodas Juan Martín-Liberal Ainara Soria Pilar Lopez Criado Almudena Garcia-Castaño Aram Boada Pablo Ayala de Miguel Susana Puig Guillermo Crespo Alfonso Berrocal 《Journal of the American Academy of Dermatology》2021,84(5):1412-1415
3.
The effect of zinc supplementation on the metabolism of tryptophan conversion to niacin was studied in 14 alcoholic patients with pellagra and in 7 male control subjects aged 21-45 y. The pellagrins received chemically defined diets based on crystalline amino acids through an enteral tube for 7 d. Patients were divided into two groups (A and B), both receiving a diet from which tryptophan, Zn, and niacin were excluded. Patients in group B, however, received 220 mg Zn sulfate orally. Upon admission the pellagra patients had low plasma Zn levels and low urinary excretion values of N'methylnicotinamide (N'MN) and N'methyl-2-pyridone-5-carboxamide (2-PYR) in relation to the control subjects (p less than 0.01). During the experimental period there was an increase in plasma Zn levels (p less than 0.005) and in urinary N'MN (p less than 0.05) and 2-PYR (p less than 0.05) excretion in the patients receiving Zn supplementation (group B). These results suggest that Zn interacts with niacin metabolism in alcoholic patients with pellagra through a probable mediation by vitamin B-6. 相似文献
4.
Carlos Ferrer Albiach Antonio Conde Moreno Marta Rodríguez Cordón Virginia Morillo Macías Ana Bouché Babiloni Inmaculada Beato Tortajada Ángel Sánchez Iglesias Alicia Francés Muñoz 《Clinical & translational oncology》2010,12(1):22-26
Hypoxia is related to poor prognosis because it is associated to chemo-and radioresistance. During recent years the evolution
of imaging methods like PET/CT and MRI has meant the appearance of new perspectives with direct implications in radiation
therapy. We discuss previous experiences in staging, planning and in the follow-up process with these techniques for measuring
tumour hypoxia. 相似文献
5.
Amalia Moreno Concepción Montón Yolanda Belmonte Miguel Gallego Xavier Pomares Jordi Real 《Archivos de bronconeumologia》2009,45(4):181-185
ObjectiveThe objective of this study was to assess the causes of death and risk factors for mortality in a cohort of patients with severe chronic obstructive pulmonary disease (COPD).Patients and methodsWe studied 203 patients with severe COPD (forced expiratory volume in 1 second [FEV1] <50%), who were attended in our respiratory department day hospital (2001-2006). Clinical variables were recorded on inclusion, and clinical course and causes of death were retrospectively reviewed.ResultsThe mean (SD) age of patients was 69 (8) years and the mean FEV1 was 30.8% (8.2%). One-hundred and nine patients died (53.7%); death was attributed to respiratory causes in 72 (80.9%), with COPD exacerbation being the most frequent specific cause within this category (48.3%). During follow-up, 18.7% required admission to the intensive care unit (ICU). Survival at 1, 3, and 5 years was 80%, 53%, and 26%, respectively. The multivariate analysis showed that mortality was associated with age, stage IV classification according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), cor pulmonale, and hospital admission during the year prior to inclusion. Need for admission to the ICU during follow-up was a factor independently associated with higher mortality.ConclusionsMortality in patients with severe COPD was high and exacerbation of the disease was one of the most frequent causes of death. Age, GOLD stage, cor pulmonale, prior admission to hospital, and need for admission to the ICU during follow-up were independent predictors of mortality. 相似文献
6.
Dipyridamole and RA-642 inhibit the production of superoxide anion and free radical damage to rat lens. 总被引:1,自引:0,他引:1
J P De la Cruz A Sintas A Moreno J Garcia-Campos F Sanchez de la Cuesta 《Pharmacology & toxicology》1991,69(3):201-204
We studied the effects of dipyridamole and RA-642 on the production of superoxide anions and on oxygen radicals-induced lipid peroxidation in lens tissue homogenates from normal rats and rats given dipyridamole or RA-642 intraperitoneally. Superoxide production was evaluated by phenazine methosulphate (PMS)-induced nitroblue tetrazolium (NBT) reduction and lipid peroxidation by ferrous sulfate and ascorbic acid (FeAs)-induced malondialdehyde (MDA) production. Dipyridamole and RA-642 showed an inhibitory effect on both assays in the experiments with lens tissue homogenates from untreated or treated rats. The extent of inhibition, however, was significantly higher in pyrimidopyrimidinic-treated rats (range of inhibition at different times of incubation was 18% versus 23-57% for dipyridamole and 14% versus 73-80% for RA-642 in the assay of MDA production, and 10% versus 33-37% for dipyridamole and 2.5% versus 11-32% for RA-642 in the assay of NBT reduction). Concentrations of dipyridamole and RA-642 in lens tissue from treated animals could not be determined (less than 0.001 micrograms/mg of tissue). Although both compounds inhibited lipid peroxidation induced by oxygen free radicals, the mechanism of action might include the role of adenosine as a mediator. 相似文献
7.
Vigilio Ballabeni Massimiliano Tognolini Simona Bertoni Renato Bruni Alessandra Guerrini Gabriela Moreno Rueda Elisabetta Barocelli 《Pharmacological research》2007,55(1):23-30
Ocotea quixos essential oil was shown to possess significant inhibitory activity of platelet aggregation and clot retraction in rodent plasma. This study is aimed at fully characterizing the antiplatelet activity of the whole essential oil and its main components trans-cinnamaldehyde and methyl cinnamate also in human plasma, at investigating the mechanism underlying such activity and at evaluating the potential antithrombotic activity of subacute treatment of mice with Ocotea essential oil. In vitro Ocotea essential oil and trans-cinnamaldehyde inhibited arachidonic acid-, U46619-, ADP-, phorbol12-myristate13-alcetate-, collagen-induced platelet aggregation and thrombin-induced clot retraction in human and rodent plasma; Ocotea oil and trans-cinnamaldehyde competitively antagonized contractions induced by thromboxane A2 receptor agonist U46619 in rat isolated aortic ring (K(B) = 18 and 3.2 microg ml(-1), respectively). In vivo Ocotea oil, orally administered in a subacute treatment (30-100 mg kg(-1) day(-1) for 5 days) to mice, prevented acute thrombosis induced by collagen-epinephrine intravenous injection. This antithrombotic activity was not accompanied by pro-haemorragic side effect, as detected by the inactivity in bleeding test, thus showing a favourable safety profile compared to the conventional antiplatelet agent, acetylsalicylic acid. Present findings indicate that Ocotea essential oil possesses potent and safe antithrombotic activity attributable to its antiplatelet and vasorelaxant effects. The main constituent trans-cinnamaldehyde seems to be the primary responsible for this activity through a putative mechanism involving the inhibition of thromboxane A2 receptors. 相似文献
8.
J. Belchi-Hernandez S. Moreno-Grau F. Sánchez-Gascón J. Bayo B. Elvira Rendueles B. Bartolomé J. M. Moreno J. Martinez Quesada R. Palacios Peláez 《Allergy》1998,53(3):241-248
Zygophyllum fahago is a herbaceous plant found widely in the Mediterranean area. There are no previous reports of its allergenicity. An aerobiologic and clinical survey was conducted in Murcia, southern Spain, to determine the quantity of airborne pollen and establish the possible role of this pollen as a cause of allergic symptoms. With a Hirst volumetric trap, we determined the atmospheric concentrations of this pollen in 1993, 1994,1995, and 1996. Of 1180 patients tested, 181 (15,34%) had a positive skin test. To determine its allergenicity, we divided 47 patients into three groups: in group 1, all the patients had symptoms of rhinoconjunctivitis plus asthma; in groups 2 and 3, rhinoconjunctivitis. In group 1, we performed a bronchial provocation test (BPT): in groups 2 and 3, we performed nasal provocation (NPT) and conjunctival provocation (CPT) tests, respectively, SDS-PAGE was used to characterize the antigenic fractions and RAST inhibition to determine cross-reactivity with other pollens. The pollen dispersion period is from May to September (445 grains/m3 ), BPT was positive in 13 of 15 patients, NPT in 14 of 16 patients, and CPT in 13 of 16 patients. RAST inhibition revealed cross-reactivity with Mercurialis, Ricinus, Olea. and Betula. SDS-PAGE identified 25 IgE antibody-binding components, five of which (60, 65, 41, 38, and 15.5/14,7 kDa) were recognized by 40% of the sera. By SDS-PAGE immunoblotting with sunflower antiprofilin rabbit serum and affinity chromatography we established that the Z. fahago extract has profilin. This study shows that this pollen becomes airborne and elicits an IgE response which triggers respiratory symptoms in allergic subjects. 相似文献
9.
E Moreno González I Landa Garcia J Calleja Kempin M Gomez Gutierrez J Arias Diaz D Riano Carrera F Parez Cerda P Moral Gutierrez F Guillen Ramirez I Garcia Garcia 《Der Chirurg》1990,61(10):701-704
Between 4/1986 to 1/1989, 74 orthotopic liver transplantation were performed in 62 patients (62 first liver transplants, 10 as second graft and two as a third graft); 57 in adults and 17 in children. The main indication for the operation was liver cirrhosis (61.4%) (the most frequent etiology was alcoholic cirrhosis, 28.5%). Six cirrhotic patients had a hepatocarcinoma (9.6%). Two received a liver and kidney transplant due to terminal renal insufficiency and hemodialysis. The most frequent indication in children was biliary atresia (33.3%). Six patients had a fulminal liver failure (9.6%). AB0 blood group compatibility was identical in 87.5%, compatible in six and incompatible in three patients. Total orthotopic liver transplantation was performed in 67 patients, and size-reduced liver was indicated in 7 patients. Extracorporeal veno-venous bypass was used in adults but never in children. In 93.1% of the transplants a single hepatic artery was anastomosed to the recipient and in 6.9% a double anastomosis was performed. In 62.5% of the patients a end-to-end choledocho-choledochostomy was performed and in 34.8% hepatico-jejunostomy was indicated. Three months postoperative mortality rate was 12.9%. Arterial stenosis and thrombosis were the most frequent complication. 相似文献
10.
Summary The present study was undertaken to investigate changes in the crystalline structure and composition of procine enamel mineral
during amelogenesis. Special attention was given to the carbonate location in the forming apatite crystal. Enamel samples
were obtained from the outer (young) secretory, inner (old) secretory, maturation, and mature (hard) enamel of the permanent
incisors of slaughtered piglets. The crystalline structure and composition of these enamel samples were studied using Fourier
transform infrared spectroscopy, X-ray diffraction, and chemical analyses. The initial enamel mineral in the outer secretory
enamel was rich in acid phosphate and carbonate. The carbonate was mainly substituted for phosphate groups in the apatite
crystals of the early (outer) secretory enamel. Developmental advancement from the outer secretory to the inner secretory
(as well as early maturation) stages brought about significant changes in crystal parameters, namely, shrinkage and expansion
of thec anda unit cell dimensions, respectively, and the shift of av
3 PO4 band to higher wavenumbers in the FTIR spectrum. X-ray diffraction patterns indicated that mineralization during the tissue
maturation was characterized by a gradual growth of enamel crystals parallel to thea-axis direction. A most prominent finding was that, with developmental advancement, a decrease in CO3 per unit mass of P (or Ca) in the tissue, and a concomitant increase in the CO3 occupying OH sites in the crystalline lattice became apparent. The overall results may reflect (1) changes in the composition
of the medium in which precipitation of enamel carbonatoapatite occurs, (2) initial formation of an acid phosphate such as
octacalcium phosphate-like mineral, or (3) modifications of the precipitating phase induced by changes in the kinetics of
the mineral formation. 相似文献