全文获取类型
收费全文 | 2049篇 |
免费 | 149篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 120篇 |
妇产科学 | 15篇 |
基础医学 | 186篇 |
口腔科学 | 61篇 |
临床医学 | 174篇 |
内科学 | 423篇 |
皮肤病学 | 46篇 |
神经病学 | 166篇 |
特种医学 | 168篇 |
外科学 | 252篇 |
综合类 | 135篇 |
预防医学 | 174篇 |
眼科学 | 56篇 |
药学 | 147篇 |
中国医学 | 1篇 |
肿瘤学 | 110篇 |
出版年
2021年 | 25篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 32篇 |
2017年 | 18篇 |
2016年 | 21篇 |
2015年 | 32篇 |
2014年 | 31篇 |
2013年 | 58篇 |
2012年 | 94篇 |
2011年 | 83篇 |
2010年 | 45篇 |
2009年 | 50篇 |
2008年 | 107篇 |
2007年 | 122篇 |
2006年 | 122篇 |
2005年 | 85篇 |
2004年 | 85篇 |
2003年 | 99篇 |
2002年 | 83篇 |
2001年 | 76篇 |
2000年 | 67篇 |
1999年 | 61篇 |
1998年 | 53篇 |
1997年 | 38篇 |
1996年 | 32篇 |
1995年 | 23篇 |
1994年 | 28篇 |
1993年 | 30篇 |
1992年 | 40篇 |
1991年 | 49篇 |
1990年 | 43篇 |
1989年 | 68篇 |
1988年 | 52篇 |
1987年 | 51篇 |
1986年 | 47篇 |
1985年 | 32篇 |
1984年 | 24篇 |
1983年 | 28篇 |
1982年 | 12篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1975年 | 14篇 |
1971年 | 7篇 |
1969年 | 17篇 |
1968年 | 9篇 |
1966年 | 8篇 |
排序方式: 共有2237条查询结果,搜索用时 15 毫秒
991.
ObjectiveTooth sensitivity is a common, painful dental condition. Consumer dental products, mostly dentifrices, play an important role in sensitivity treatment. The objective of this review is to describe a new mouthwash-based desensitizing technology.DataBackground literature concerning desensitizing products is reviewed. Potassium salts are the most commonly used active ingredients in desensitizing dentifrices. Clinical studies show that while potassium salt dentifrices are generally effective; most formulations require several weeks to exert their desensitizing effect. Recently, a new desensitizing dentifrice containing the amino acid arginine was introduced. This dentifrice acts to occlude the dentinal tubules, and has been shown to be highly effective in multiple clinical studies. This arginine-containing dentifrice has also been shown to provide instant relief of sensitivity pain when applied directly to the sensitive tooth surface.In contrast to dentifrices, there are few desensitizing mouthwashes available. Building on the success of the arginine-based dentifrice, an arginine-based mouthwash formula was developed and tested.SourcesPublished studies in peer-reviewed publications.Study selectionControlled and blinded clinical studies to provide evidence of efficacy. In vitro studies are included to indicate the mechanism of action. This review includes studies testing the new arginine-based desensitizing mouthwash.ConclusionClinical findings indicate that this new desensitizing mouthwash, based on the Pro-Argin? mouthwash technology effectively reduces sensitivity symptoms and can be used alone or as a adjunct to the use of the arginine-containing dentifrice in the home treatment of tooth sensitivity. 相似文献
992.
993.
994.
Atkinson K; Incefy GS; Storb R; Sullivan KM; Iwata T; Dardenne M; Ochs HD; Good RA; Thomas ED 《Blood》1982,59(5):1073-1077
We tested the hypothesis that chronic graft-versus-host disease (GVHD) is due to inadequate thymic function by examining pretransplant serum levels of facteur thymique serique (FTS). Four of five patients with no detectable FTS activity developed chronic GVHD, while one of four with some FTS activity did. Further patient numbers are needed to confirm or reject this hypothesis. We further postulated that chronic GVHD, whatever its cause, involves thymic epithelium as a target organ. When tested 11 mo or more posttransplant, patients with chronic GVHD had lower absolute FTS levels (p less than 0.02) and lower age-corrected levels (p = 0.05) than patients without chronic GHVD. Low values in chronic GVHD were associated with the disease itself and not its therapy. These findings show that thymic epithelial secretory function is impaired in chronic GVHD, and this may in part be responsible for the immunodeficiency characteristic of these patients. 相似文献
995.
M M Weissman G L Klerman J S Markowitz R Ouellette 《The New England journal of medicine》1989,321(18):1209-1214
Panic disorder, which is found in about 1.5 percent of the population at some time in their lives, includes recurrent episodes of sudden, unpredictable, intense fear accompanied by symptoms such as palpitations, chest pain, and faintness. Panic attacks, which do not meet these diagnostic criteria fully, are two to three times more prevalent. Since panic symptoms can mimic those of other medical disorders, patients with these symptoms use medical services frequently. To determine the risk of suicidal ideation and suicide attempts in panic disorder and attacks, we studied a random sample of 18,011 adults drawn from five U.S. communities. Subjects who had panic disorder, as compared with other psychiatric disorders, had more suicidal ideation and suicide attempts, with an adjusted odds ratio for suicide attempts of 2.62 (95 percent confidence interval, 1.83 to 3.74). The odds ratio was 17.99 (95 percent confidence interval, 12.18 to 26.58) when the group with panic disorder was compared with subjects who had no psychiatric disorder. Twenty percent of the subjects with panic disorder and 12 percent of those with panic attacks had made suicide attempts. These results could not be explained by the coexistence of major depression or of alcohol or drug abuse. We conclude that panic disorder and attacks are associated with an increased risk of suicidal ideation and suicide attempts. Physicians working in general medical settings and emergency departments should be alert to this problem. 相似文献
996.
Legionella prosthetic-valve endocarditis 总被引:5,自引:0,他引:5
L S Tompkins B J Roessler S C Redd L E Markowitz M L Cohen 《The New England journal of medicine》1988,318(9):530-535
Since 1982 seven patients at Stanford University Medical Center have been shown to have prosthetic-valve endocarditis caused by Legionella pneumophila or L. dumoffii. We studied the clinical features of legionella endocarditis at the time of diagnosis and performed a case-control study to analyze risk factors for the infection. All patients with endocarditis had a chronic course (3 to 19 months after surgery) of fever, night sweats, weight loss, and anemia, but no embolic events or immune-complex deposition disease. Five patients required surgical replacement of their infected prosthetic valves. The case-control study revealed that during the early postoperative period, patients who later contracted legionella endocarditis were more likely to have had symptoms and signs attributable to postcardiomyotomy syndrome than were patients who did not contract endocarditis (P less than 0.013). Examination of the legionella isolates by means of molecular techniques demonstrated that the Stanford L. pneumophila isolates were genotypically identical to isolates from the hospital drinking water. L. dumoffii isolates from patients with endocarditis were derived from a single strain apparently unique to this medical center. We conclude that legionella infection was nosocomially acquired in the perioperative period. These cases demonstrate an expanding spectrum of illness caused by legionella species and emphasize the need to consider legionella as a cause of "culture-negative" endocarditis. 相似文献
997.
A premature infant presented with ectopia cordis, occipital meningocele, and manifestations of trisomy 18; cytogenetic analysis confirmed a 47,XX,+18 chromosome constitution. While most cases of ectopia cordis appear as isolated, sporadic defects, careful evaluation is warranted to detect evidence of an associated chromosome abnormality. 相似文献
998.
Evaluation of monoclonal antibody-based capture enzyme immunoassays for detection of specific antibodies to measles virus. 总被引:3,自引:4,他引:3 下载免费PDF全文
D D Erdman L J Anderson D R Adams J A Stewart L E Markowitz W J Bellini 《Journal of clinical microbiology》1991,29(7):1466-1471
Monoclonal antibodies to the hemagglutinin protein, fusion protein, phosphoprotein, matrix protein, and nucleoprotein of measles virus were evaluated as detector antibodies in capture enzyme immunoassays (EIAs) for the detection of specific serum immunoglobulin G (IgG), IgA, and IgM antibodies to measles virus. A pool of monoclonal antibodies to hemagglutinin protein and nucleoprotein proved optimal and was further evaluated. Specific IgM was detected in 97% of adolescents with clinical measles, 97% of infants 3 weeks postvaccination, and less than 1% of normal serum specimens. Specific IgA antibodies were found in 97% of adolescents with clinical measles, 97% of infants 3 weeks postvaccination, and less than 1% of normal serum specimens. Specific IgA antibodies were found in 97% of clinical measles cases and vaccinees, in 26% of healthy persons, and in 36% of infants 8 months postvaccination; consequently, IgA antibodies were not a useful indicator of recent measles infection. A significant increase in IgG antibodies between paired specimens was detected in 92% of clinical cases and all vaccinees. Only 59% of infant specimens had persistent IgG antibodies as detected by capture EIA at 8 months postvaccination, whereas all specimens had antibodies as detected by hemagglutination inhibition and plaque neutralization. An alternative indirect EIA, in which antigen was directly absorbed to the solid phase, was more sensitive than the capture design, detecting IgG antibodies in all infants postvaccination. When standardized with a microneutralization assay for the detection of persistent antibodies, the indirect IgG EIA gave predictive values for positive and negative tests exceeding 90%. Our capture IgM and indirect IgG EIAs provide a practical combination of serologic tests for the determination of acute measles virus infection and past exposure to measles virus or vaccine, respectively. 相似文献
999.
An elastin gene mutation producing abnormal tropoelastin and abnormal elastic fibres in a patient with autosomal dominant cutis laxa 总被引:4,自引:0,他引:4
Tassabehji M; Metcalfe K; Hurst J; Ashcroft GS; Kielty C; Wilmot C; Donnai D; Read AP; Jones CJP 《Human molecular genetics》1998,7(6):1021-1028
Elastin is the protein responsible for the characteristic elastic
properties of many tissues including the skin, lungs and large blood
vessels. Loss-of-function mutations in the elastin gene are known to cause
the heart defect supravalvular aortic stenosis (SVAS). We and others have
identified deletions, nonsense mutations and splice site mutations in SVAS
patients that abolish the function of one elastin gene. We have now
identified an elastin mutation in a patient with a completely different
phenotype, the rare autosomal dominant condition cutis laxa. A frameshift
mutation in exon 32 of the elastin gene is predicted to replace 37 amino
acids at the C-terminus of elastin by a novel sequence of 62 amino acids.
mRNA and immunoprecipitation studies show that the mutant allele is
expressed. Electron microscopy of skin sections shows abnormal branching
and fragmentation in the amorphous elastin component, and
immunocytochemistry shows reduced elastin deposition in the elastic fibres
and fewer microfibrils in the dermis. These findings suggest that the
mutant tropoelastin protein is synthesized, secreted and incorporated into
the elastic matrix, where it alters the architecture of elastic fibres.
Interference with cross- linking would reduce elastic recoil in affected
tissues and explain the cutis laxa phenotype.
相似文献
1000.
GS Ghosh S Gudmundsson 《BJOG : an international journal of obstetrics and gynaecology》2009,116(3):424-430
Objective To compare umbilical and uterine artery Doppler in predicting outcome of pregnancies suspected of fetal growth restriction (FGR).
Design A prospective study included 353 singleton pregnancies complicated by an FGR fetus.
Setting University Hospital setting.
Sample Pregnancies suspected of FGR diagnosed by ultrasound fetal biometry during a 5-year period.
Main outcome measure Perinatal outcome in relation to uterine and umbilical artery Doppler.
Methods The women underwent Doppler examination of the umbilical and uterine arteries. Results from the uterine, but not the umbilical artery, were blind to the woman and managing obstetrician. The Doppler results were related to perinatal outcomes including small for gestational age newborns, caesarean delivery, premature delivery (<37 weeks of gestation) and admission of the newborn to a neonatal intensive care unit.
Results Abnormal uterine artery Doppler velocimetry was seen in 120 (33.4%) pregnancies and abnormal umbilical artery Doppler in 102 (28.4%). There was a statistically significant correlation between abnormal Doppler of both the umbilical and uterine arteries and adverse outcome of pregnancy. The two vessels were comparable in predicting adverse outcome. Women with normal umbilical artery Doppler (251) were analysed separately. Abnormal uterine artery Doppler, seen in 61 (24.3%) of those women, showed a statistically significant correlation for adverse outcome of pregnancy.
Conclusions Doppler examinations of the uterine and/or the umbilical arteries seem to be comparable as predictors of outcome in pregnancies complicated by FGR. Including uterine artery Doppler in the surveillance of growth-restricted fetuses might detect a group of pregnancies at high risk, even though the umbilical artery Doppler was normal. 相似文献
Design A prospective study included 353 singleton pregnancies complicated by an FGR fetus.
Setting University Hospital setting.
Sample Pregnancies suspected of FGR diagnosed by ultrasound fetal biometry during a 5-year period.
Main outcome measure Perinatal outcome in relation to uterine and umbilical artery Doppler.
Methods The women underwent Doppler examination of the umbilical and uterine arteries. Results from the uterine, but not the umbilical artery, were blind to the woman and managing obstetrician. The Doppler results were related to perinatal outcomes including small for gestational age newborns, caesarean delivery, premature delivery (<37 weeks of gestation) and admission of the newborn to a neonatal intensive care unit.
Results Abnormal uterine artery Doppler velocimetry was seen in 120 (33.4%) pregnancies and abnormal umbilical artery Doppler in 102 (28.4%). There was a statistically significant correlation between abnormal Doppler of both the umbilical and uterine arteries and adverse outcome of pregnancy. The two vessels were comparable in predicting adverse outcome. Women with normal umbilical artery Doppler (251) were analysed separately. Abnormal uterine artery Doppler, seen in 61 (24.3%) of those women, showed a statistically significant correlation for adverse outcome of pregnancy.
Conclusions Doppler examinations of the uterine and/or the umbilical arteries seem to be comparable as predictors of outcome in pregnancies complicated by FGR. Including uterine artery Doppler in the surveillance of growth-restricted fetuses might detect a group of pregnancies at high risk, even though the umbilical artery Doppler was normal. 相似文献