全文获取类型
收费全文 | 38221篇 |
免费 | 2041篇 |
国内免费 | 147篇 |
学科分类
医药卫生 | 40409篇 |
出版年
2024年 | 26篇 |
2023年 | 238篇 |
2022年 | 384篇 |
2021年 | 1403篇 |
2020年 | 744篇 |
2019年 | 1094篇 |
2018年 | 1279篇 |
2017年 | 838篇 |
2016年 | 933篇 |
2015年 | 1064篇 |
2014年 | 1584篇 |
2013年 | 1926篇 |
2012年 | 3161篇 |
2011年 | 3285篇 |
2010年 | 1877篇 |
2009年 | 1573篇 |
2008年 | 2652篇 |
2007年 | 2667篇 |
2006年 | 2590篇 |
2005年 | 2507篇 |
2004年 | 2132篇 |
2003年 | 1927篇 |
2002年 | 1710篇 |
2001年 | 194篇 |
2000年 | 142篇 |
1999年 | 223篇 |
1998年 | 289篇 |
1997年 | 224篇 |
1996年 | 200篇 |
1995年 | 190篇 |
1994年 | 146篇 |
1993年 | 110篇 |
1992年 | 106篇 |
1991年 | 85篇 |
1990年 | 52篇 |
1989年 | 39篇 |
1988年 | 46篇 |
1987年 | 44篇 |
1986年 | 44篇 |
1985年 | 52篇 |
1984年 | 55篇 |
1983年 | 54篇 |
1982年 | 43篇 |
1981年 | 50篇 |
1980年 | 60篇 |
1979年 | 28篇 |
1978年 | 36篇 |
1977年 | 43篇 |
1976年 | 28篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
991.
The purpose of this investigation was to measure the effectiveness of the antimuscarinic drug atropine sulfate in the treatment
of chronic drooling in a patient with a history of severe closed head injury and resultant widespread oral neuromuscular and
higher cortical disturbances. Results of the A-B-A-B-A-B withdrawal paradigm, chosen to demonstrate the functional relationship
between drug therapy and the degree of drooling, revealed that administration of atropine sulfate reduced by more than 50%
of baseline levels the amount of resting secretion, intraoral accumulation, and pharyngeal-laryngeal pooling of saliva, with
negligible side effects. These results are discussed and compared to the alternative drug and surgical approaches to the alternative
drug and surgical approaches to treatment that have been the primary focus of recent research on drooling. 相似文献
992.
BACKGROUND/AIMS: Liver growth, induced by partial hepatectomy of the organ is a precisely regulated process during which a radical reorganisation of metabolism occurs as the hepatocytes become committed to enter the cell cycle. Recent studies have shown the importance of the endocytic compartment in the control of lipid and protein intracellular trafficking but also in the control of the signal transduction events, which eventually will trigger the initiation of DNA synthesis and the subsequent cell division. METHODS: We isolated endosomes at different times after partial hepatectomy in male rats and compared with endosomes isolated from sham-operated animals. Also, bile was collected and analysed by 2D-gel electrophoresis. RESULTS: The amount of late endosomes isolated from regenerating livers decreased, concomitant with decreased cathepsin D specific enzyme activity. Furthermore, secretion of horseradish peroxidase, pIgA and transferrin increased in the pre-replicative phase of liver regeneration. CONCLUSIONS: At the early stages of liver regeneration, the hepatocellular transport pathway towards degradation (late endosomes and lysosomal pathway) decreases, but the transcytosis and the bile secretion of several major proteins increases. 相似文献
993.
994.
Catalán J Pérez P del Valle JC de Paz JL Kasha M 《Proceedings of the National Academy of Sciences of the United States of America》2002,99(9):5799-5803
A mechanism is proposed for the formation in gas phase, during a short time, of the delicately symmetrical coplanar C(2h) classic 7-azaindole (7AI) doubly hydrogen-bonded dimer. Of the five card-pack or otherwise random geometry structures most likely to be formed in the supersonic jet expansion molecular beam, none would be an obvious precursor to the C(2h) dimer. One unstable dimer with dipole-dipole, van der Waals, and plane-to-plane hydrogen bonding is shown to be capable of unhinging about the hydrogen-bond pair as an axis, from 0 degrees to 90 degrees to 180 degrees, yielding a deep minimum for the C(2h) structure with its delicate geometry and symmetry. This relaxation mechanism is feasible in the 3-micros interval between the nozzle escape and the first laser pulse interception of the molecular beam. In the second part of the paper four published mechanisms are compared for concerted vs. two-step biprotonic phototransfer for the 7AI dimers. The dependence of the latter two models on H-atom instead of proton-transfer as an intermediate step negates the mechanism in a singlet (pi,pi*) electronic state by the valency repulsion, in the 3-electron orbital that would be generated. The concerted mechanism for biprotonic phototransfer is reaffirmed by the analysis of the quantum mechanical conditions set on the biprotonic transfer in the photo-excited molecular 7AI pair. 相似文献
995.
Leopoldo Luiz Dos SANTOS‐NETO Elvis Henrique Santos ANDRADE Patrícia Eiko YAMAKAWA Carlos Hirokatsu WATANABE SILVA 《International journal of rheumatic diseases》2007,10(2):140-142
Both Sjögren's syndrome and rosacea present clinical manifestations that include ocular involvement. We report a case of a 45‐year‐old woman with a history of persistent erythematous malar rash, associated with conjunctival hyperemia, xerophthalmia and blefaritis. The patient filled the current classification criteria proposed for Sjögren's syndrome and those for rosacea. The coexistence of these diseases has not been previously described in the literature. Both diseases have similar symptoms and different treatment approaches. We believe that it is important for clinicians to identify this association in order to provide better care for the patient. 相似文献
996.
António Saragoça M.D. Brito Barros M.D. Carlos Santos Soares M.D. 《Digestive diseases and sciences》1964,9(5):337-344
Summary 1. In 168 necropsies performed during a period of less than 3 years, 6 cases of primary carcinoma of the liver were found, an incidence of 3.57%. Another case was proved by needle biopsy, but autopsy was not obtained. Six of the 7 carcinomas were diagnosed during the life of the patients concerned.2. Clinical diagnosis was established upon a history of progressive and rapid general deterioration of health, with anorexia and marked emaciation accompanied by painful nodular hepatomegaly and fever, and later by moderate jaundice and serosanguineous ascitic effusion.3. The disproportion between the slightly elevated values of serum bilirubin and the high alkaline phosphatase activity, together with an increase of the transaminase levels, were the most important laboratory data, allowing the diagnosis of expanding space-occupying lesion (though not specifying its precise nature).The practical application of these criteria to diagnosis may be rewarded with an increase in in-vivo diagnosis of neoplasms of the liver.Pathologic examinations were carried out at the Instituto de Anatomia Patológica. 相似文献
997.
Dr. A.J. Chorao de Aguiar Chefe de Clínica Dr. H. Guimaraes Mdico Especialista Dr. A. Raposo Interno do Internato Complementar de Cardiologia M. Cerqueira Gomes R. Paula Pinto R. Gonalves Fernando Pdua Virginia Lopes Drio Reis Carlos Ribeiro Isabel Lacximy Ramiro Correia 《Journal of electrocardiology》1979,12(4):381-386
998.
Maria-Fernanda Solá-Ruiz Carolina Pérez-Martínez José-Javier Martín-del-Llano Carmen Carda-Batalla Carlos Labaig-Rueda 《Medicina oral, patología oral y cirugía bucal》2015,20(1):e88-e93
Objectives: To observe human osteoblast behavior cultured in vitro on titanium discs (Ti) in relation to surface roughness and melatonin application.
Study Design: Human osteoblasts (MG-63) were cultured on 60 Ti6Al4V discs divided into three groups: Group I: discs treated with dual acid etching; Group II dual acid etching and blasting with calcium phosphate particles; Group III (control) machined discs. Surface roughness and topography of the discs were examined with scanning electron microscope (SEM) and confocal laser scanning electron microscope( CLSM).
Osteoblast adhesion, proliferation and cell morphology were determined by means of fluorescence microscopy with Image-Pro Plus software and SEM.
Results: Group II presented the roughest discs, while the least rough were Group III. Cell adhesion was greatest in Group II. The addition of melatonin improved cell proliferation.
Conclusions: 1. Surface treatments (dual acid etching, calcium phosphate impaction) increase surface roughness in comparison with machined titanium.
2. Greater surface roughness tends to favor cell adhesion after 24-hour cell culture.
3. The addition of melatonin tends to favor osteoblast proliferation.
Key words:Osteoblasts, titanium, roughness, melatonin, dental implants, osseointegration. 相似文献
999.
1000.