全文获取类型
收费全文 | 14748篇 |
免费 | 803篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 288篇 |
儿科学 | 396篇 |
妇产科学 | 469篇 |
基础医学 | 2072篇 |
口腔科学 | 1108篇 |
临床医学 | 895篇 |
内科学 | 3245篇 |
皮肤病学 | 520篇 |
神经病学 | 1303篇 |
特种医学 | 408篇 |
外科学 | 2229篇 |
综合类 | 54篇 |
一般理论 | 3篇 |
预防医学 | 928篇 |
眼科学 | 194篇 |
药学 | 762篇 |
中国医学 | 77篇 |
肿瘤学 | 660篇 |
出版年
2023年 | 97篇 |
2022年 | 269篇 |
2021年 | 515篇 |
2020年 | 354篇 |
2019年 | 419篇 |
2018年 | 507篇 |
2017年 | 354篇 |
2016年 | 370篇 |
2015年 | 473篇 |
2014年 | 655篇 |
2013年 | 746篇 |
2012年 | 1150篇 |
2011年 | 1230篇 |
2010年 | 740篇 |
2009年 | 631篇 |
2008年 | 1051篇 |
2007年 | 1023篇 |
2006年 | 984篇 |
2005年 | 959篇 |
2004年 | 731篇 |
2003年 | 652篇 |
2002年 | 586篇 |
2001年 | 75篇 |
2000年 | 56篇 |
1999年 | 86篇 |
1998年 | 101篇 |
1997年 | 111篇 |
1996年 | 81篇 |
1995年 | 83篇 |
1994年 | 58篇 |
1993年 | 61篇 |
1992年 | 34篇 |
1991年 | 36篇 |
1990年 | 29篇 |
1989年 | 19篇 |
1988年 | 29篇 |
1987年 | 20篇 |
1986年 | 19篇 |
1985年 | 12篇 |
1984年 | 23篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 10篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
31.
BACKGROUND: Antileukotriene agents have been shown to be beneficial in chronic asthma. Although patients with cough variant asthma have cough with minimal wheezing and dyspnea, airway hyperresponsiveness from chronic inflammation is believed to be the underlying mechanism. OBJECTIVE: To evaluate the effectiveness of montelukast, a leukotriene receptor antagonist, in the treatment of cough variant asthma. METHODS: Fourteen patients with cough variant asthma participated in a randomized, double-blind, placebo-controlled trial with a 7- to 10-day baseline period and a 4-week treatment period with montelukast, 10 mg, or placebo daily. Inclusion criteria were (1) chronic cough with a duration of at least 4 weeks with minimal or no wheezing or dyspnea and (2) forced expiratory volume in 1 second of 50% to 85% of predicted and reversibility of 12% with use of an inhaled beta-agonist or forced expiratory volume in 1 second greater than 85% and positive methacholine challenge results. Patients fulfilled the minimum criteria for cough frequency and symptom scores for randomization. RESULTS: Eight patients received montelukast and 6 received placebo. The primary efficacy variable, mean percentage change from baseline in cough frequency, was significantly improved by the second week, and by the fourth week the mean percentage change from baseline was 75.7% for the treatment group and 20.7% for the placebo group. CONCLUSIONS: The leukotriene receptor antagonist montelukast seems to be effective in the treatment of cough variant asthma. Larger studies are recommended to confirm this effect. 相似文献
32.
H. William Scott Jr. M.D. Craig R. Sussman M.D. David L. Page M.D. Norman W. Thompson M.D. Milton D. Gross M.D. Ricardo Lloyd M.D. 《World journal of surgery》1986,10(4):646-652
Since the syndrome of primary hyperaldosteronism was described by Jerome Conn in 1955, over 300 patients with this disorder have been identified in the medical centers of Vanderbilt University and the University of Michigan. The most frequent cause of this endocrinopathy has been a solitary adenoma of the adrenal cortex (72%); bilateral adrenocortical hyperplasia has been the cause of primary hyperaldosteronism in 27% of cases; less frequently, the cause has been multiple and/or bilateral adenomas (1%). During the last 4 years in these 2 medical centers, we have encountered 3 patients who have had biochemically proven primary hyperaldosteronism due to adrenocortical carcinoma. Each of these unusual cases is summarized with review of the recent literature.
Presented at the International Association of Endocrine Surgeons in Paris, September 1985. 相似文献
Resumen Desde la descripción del síndrome de hiperaldosteronismo primario por Jeremo Conn en 1955, más de 300 pacientes con esta entidad han sido identificados en nuestros 2 centros médicos, la Universidad de Vanderbilt (Nashville) y la Universidad de Michigan (Ann Arbor). La causa más frecuente de esta endocrinopatía ha sido el adenoma solitario de la corteza suprarrenal (72%); la hiperplasia adrenocortical bilateral ha sido la causa del hiperaldosteronismo primario en 27% de los casos; con menor frecuencia se han presentado los adenomas multiples y/o bilaterales (1%). En los 4 últimos años hemos encontrado 3 pacientes con hiperaldosteronismo primario comprobado bioquímicamente producido por carcinoma adrenocortical. Se presenta cada uno de estos casos poco usuales junto con una revisión de la literatura reciente.
Résumé Depuis que le syndrome d'hyperaldostéronisme primitif a été décrit par Jerôme Conn en 1955 plus de 300 sujets qui en étaient victimes ont été identifiés à la Vanderbilt University de Nashville et à l'University of Michigan de Ann Arbor. La cause la plus fréquente de cette endocrinopathie répond à un adénome solitaire de la cortico-surrénale (72%) alors que l'hyperplasie corticale des 2 surrénales est plus rarement à son origine (27%), les adénomes multiples et/ou bilatéraux étant rarissimes (1%). Au cours des 4 dernières années 3 cas d'hyperaldosteronisme dû à un cancer de la cortico-surrénale ont été observés dans les 2 centres. Chacun de ces cas exceptionnels est exposé cependant que la littérature récente concernant l'hyperalderosteronisme est analysée.
Presented at the International Association of Endocrine Surgeons in Paris, September 1985. 相似文献
33.
34.
Patients presented at the emergency room with chest pain, non-characteristicECG changes and negative Troponin represent a very frequentclinical dilemma. These patients are often hospitalized unnecessarilyand frequently undergo non-invasive and even invasive investigationswhich turn out to be negative. Occasionally, they may falselybe discharged from the ER and eventually develop a major cardiacevent. The most common and apparently the cheapest test employedin the evaluation of these patients is standard exercise ECG.Jeetley et al.1 prospectively studied a large group ofsuch patients. The patients 相似文献
35.
Ricardo Mitrani Momo Vasilic August Bruguera 《Practical procedures & aesthetic dentistry》2005,17(1):71-8; quiz 80
Recent scientific and technological developments have allowed the dental team to execute revolutionary restorative treatments that would have once been considered unfeasible. This article describes a restorative alternative for fixed implant-supported reconstructions, consisting of a CAD/CAM-generated framework and CAD/CAM-generated all-ceramic cement-retained restorations. Distinct advantages of this type of restoration include the passive fit of the framework, the ability of the ceramist to fabricate individual restorations independent from the framework, and the delivery of optimal aesthetics. 相似文献
36.
Doris Cerecedo Sirenia González Mónica Mondragón Elba Reyes Ricardo Mondragón 《Blood coagulation & fibrinolysis》2006,17(2):161-164
Platelets are cell fragments with dynamic properties involved in clot formation after tissue damage. Platelet activation causes a change in shape, secretion of intracellular granules and aggregation with each other through the cytoskeleton components and biochemical changes. Platelet adhesion, considered as the major event in haemostasis, has been studied in several in-vitro and in-vivo models to evaluate the feasible thrombogenicity of some materials, the dynamics of specific receptors, as well as the effect of different buffers and inhibitors in this process. In spite of the numerous reports about platelet activation, to date there is no information available about the fine structure of the platelet-platelet and platelet-substrate interactions. In the present report we describe an in-vitro system that allows the visualization of these interactions: platelets are adhered to an inert substrate, and interactions with suspended platelets as a process to initiate the formation of thrombi was followed by ultramicrotomy and transmission electron microscopy. 相似文献
37.
38.
Sylvie Di Filippo Bertrand Semiond Ricardo Roriz Francois Sassolas Marie José Raboisson André Bozio 《The Journal of heart and lung transplantation》2003,22(8):876-882
BACKGROUND: Coronary vasculopathy is the main cause of cardiac graft failure. Because yearly coronary angiography is invasive in children, a non-invasive method for detecting graft vasculopathy is needed. The aim of this study was to test dobutamine-stress echocardiography in a pediatric population to determine its feasibility, safety and reliability in the detection of graft coronary artery disease. METHODS: Eighteen patients, aged 2 days to 16.8 years at transplantation (mean 8.4 years), underwent 44 dobutamine-stress echocardiography (DSE) exams, at a follow-up of 1.1 to 11.8 years (mean 5.1 years). Selective coronary angiography was performed for comparison. Echocardiographic recordings were obtained in 4 standard views of the left ventricle and measurements carried out within the frames of a 16-segment model. Segmental scores of contractility were obtained for each segment and a total segmental contractility index was calculated at each stage. RESULTS: All patients reached the maximum dose stage. Maximum heart rate was 57% to 90% of predicted maximum. Maximum systolic blood pressure reached 190 mmHg. Segmental scores were normal in 37 and abnormal in 7 cases. Echographic results were concordant with angiography in 82% and discordant in 18% of the cases (4 negative DSEs with minor angiographic lesions, 2 positive DSEs with normal angiography), but there was no significant angiographic lesion with normal DSE. CONCLUSIONS: DSE is a safe and highly feasible non-invasive technique in transplanted children. A normal DSE study successfully predicts the absence of significant coronary artery disease in the post-transplant population. 相似文献
39.
Analysis of epidermal growth factor receptor and activated epidermal growth factor receptor expression in pituitary adenomas and carcinomas. 总被引:2,自引:0,他引:2
Onder Onguru Bernd W Scheithauer Kalman Kovacs Sergio Vidal Long Jin Shuya Zhang Katharina H Ruebel Ricardo V Lloyd 《Modern pathology》2004,17(7):772-780
Epidermal growth factor receptor plays an important role in the pathogenesis of many malignancies. Various growth factors, including epidermal growth factor receptor, have been shown to influence pituitary tumor growth and differentiation. To analyze the role of epidermal growth factor receptor in pituitary tumor development, we examined normal pituitaries (n=8), pituitary adenomas (n=158), and pituitary carcinomas (n=7) for expression of epidermal growth factor receptor protein and messenger RNA using tissue microarrays and RT-PCR. We also examined (a) the expression of phospho-epidermal growth factor receptor, the activated form of epidermal growth factor receptor, in pituitary tumors and normal pituitaries by immunohistochemistry and (b) the effects on epidermal growth factor receptor expression of treating pituitary cells (HP75 cell line) with epidermal growth factor. Epidermal growth factor receptor and the phosphorylated variant expression were present in normal pituitary cells. Epidermal growth factor receptor messenger RNA was also detected in normal pituitaries, pituitary adenomas, and carcinomas by in situ hybridization and RT-PCR. Most pituitary adenomas showed expression of epidermal growth factor receptor and the phosphorylated variant. Nonfunctional adenomas showed higher levels of expression of epidermal growth factor receptor (76 vs 34%) and of phospho-epidermal growth factor receptor (26 vs 8%) as compared to functional adenomas. Five of seven pituitary carcinomas showed strong expression of both epidermal growth factor receptor and phospho-epidermal growth factor receptor. When a human pituitary cell line (HP75) was cultured in the presence of epidermal growth factor receptor, there was an increase in the levels of both epidermal growth factor receptor and phospho-epidermal growth factor receptor after 5 h of treatment, thus confirming that epidermal growth factor receptor signaling was active in pituitary tumors. These results indicate that activated epidermal growth factor receptor is expressed in pituitary adenomas and carcinomas. Higher levels in pituitary carcinomas suggest a role in pituitary tumor progression. 相似文献