全文获取类型
收费全文 | 596篇 |
免费 | 44篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 47篇 |
妇产科学 | 10篇 |
基础医学 | 99篇 |
口腔科学 | 14篇 |
临床医学 | 57篇 |
内科学 | 78篇 |
皮肤病学 | 7篇 |
神经病学 | 12篇 |
特种医学 | 94篇 |
外科学 | 24篇 |
综合类 | 16篇 |
一般理论 | 1篇 |
预防医学 | 104篇 |
眼科学 | 31篇 |
药学 | 22篇 |
肿瘤学 | 36篇 |
出版年
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 8篇 |
2013年 | 15篇 |
2012年 | 15篇 |
2011年 | 6篇 |
2010年 | 20篇 |
2009年 | 15篇 |
2008年 | 13篇 |
2007年 | 21篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 14篇 |
2002年 | 10篇 |
2001年 | 14篇 |
2000年 | 22篇 |
1999年 | 9篇 |
1998年 | 29篇 |
1997年 | 41篇 |
1996年 | 32篇 |
1995年 | 19篇 |
1994年 | 17篇 |
1993年 | 6篇 |
1992年 | 12篇 |
1991年 | 17篇 |
1990年 | 19篇 |
1989年 | 14篇 |
1988年 | 19篇 |
1987年 | 6篇 |
1986年 | 13篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 14篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1978年 | 4篇 |
1977年 | 13篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1972年 | 6篇 |
1970年 | 5篇 |
1939年 | 5篇 |
1938年 | 4篇 |
1932年 | 4篇 |
排序方式: 共有653条查询结果,搜索用时 15 毫秒
1.
ZQ Yin MD SG Crewther PhD B Pirie BSc DP Crewther PhD 《Clinical & experimental ophthalmology》1997,25(4):107-109
Purpose: It was investigated whether alterations in neuronal structure and function occasioned by strabismic amblyopia also may be reflected in alterations in the expression on Y type neurons of a Cat-301 antibody sensitive antigen in the lateral geniculate nucleus (LGN) and cortex of our cat model of strabismic amblyopia. Methods/Results: The percentage of positively labelled cells was reduced in LGN laminae that received input from the deviated eye in strabismic amblyopic cats compared with normal cats. In the strabismic cortex, the density of immunopositive neurons was significantly reduced compared with normal, the effect being most pronounced in layer IV Conclusions: Despite previous physiological recordings indicating a decrease in X-cell associated acuity in strabismic amblyopia, the present findings imply that the changes in the early visual experience occasioned by strabismus also produce specific molecular changes in theY neuronal class. 相似文献
2.
A community organization strategy was used in the delivery of health education programs by the Minnesota Heart Health Program (MHHP). The effectiveness of the approach was evaluated to determine whether an enhanced health promotion delivery system had developed in MHHP communities by the end of the intervention period or whether the intervention had suppressed community efforts. 'Social connectedness' among providers, as measured by health promotion network size, also was expected to be higher in intervention communities. Six Midwestern communities were studied: the MHHP communities of Mankato, MN and Fargo, ND--Moorhead, MN with two matched comparison communities for each (Winona, MN, St Cloud, MN and Eau Claire, WI, Sioux Falls, SD). Nine areas of health promotion were assessed, including the five heart disease risk factor areas where education campaigns had been implemented (smoking cessation, weight loss, eating patterns, exercise, and heart disease education and screening) and four other areas where community programs are common (chemical dependency; home, personal and drivers' safety; stress management; and cancer education and screening). Indicators of the health promotion delivery system were developed (program options and program participation), and data were collected in separate surveys of 438 community organization providers and 320 larger worksites in the six communities. Results showed no suppression of health promotion delivery systems in MHHP communities. Instead, the survey of larger worksites showed that there was greater participation in heart disease health promotion and greater 'social connectedness' among worksites in both intervention communities. Also, there were more heart disease health promotion programs in the larger intervention community of Fargo-Moorhead. In the community organization survey, results favored the larger intervention community over its comparison communities in heart disease health promotion program options and in 'social connectedness' but not in program participation. However, survey results favored one of the comparison communities (Winona) over the smaller intervention community (Mankato) on all indicators in this survey. The greater impact of the MHHP intervention at worksites suggests that institutionalization may be more likely in stable organizations whose current needs and interests fit the goals of the intervention activity. 相似文献
3.
Dithiothreitol prevents age-associated decrease in oocyte/conceptus viability in vitro 总被引:2,自引:0,他引:2
The present study was designed to ascertain whether the negative effects on
reproductive potential of post-ovulatory ageing in vitro of oocytes can be
prevented by antioxidant therapy. Mouse metaphase II (MII) oocytes were
aged in vitro for 12 h prior to insemination in the presence of varying
concentrations of L-ascorbic acid, 6-methoxy-
2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), L-cystine
dihydrochloride, ethylenediaminetetraacetic acid (EDTA), beta-
mercaptoethanol and DL-dithiothreitol (DTT). In-vitro ageing of oocytes was
associated with lower fertilization rate, higher proportion of concepti
exhibiting cellular fragmentation at 24 h post-insemination and lower
percentage of concepti reaching the blastocyst stage. Ascorbic acid, Trolox
and EDTA had no effect on cellular fragmentation or potential of oocytes
for development. However, the probability of an oocyte reaching the
blastocyst stage was decreased (P < or = or = 0.05) in oocytes incubated
in the presence of L-cystine (50 and 500 microM) and beta-mercaptoethanol
(5, 50 and 500 microM) when compared to control aged oocytes.
Age-associated cellular fragmentation at 24 h post-insemination was
partially prevented (P < or = 0.05) by incubating oocytes in the
presence of beta-mercaptoethanol (500 microM). DTT (50 and 500 microM)
increased (P < or = 0.05) fertilization rate and number of cells at 81 h
post-insemination to levels similar to those exhibited by control oocytes.
Furthermore, both age-associated fragmentation at 24 h post-insemination (P
< or = 0.05) and decreased potential of oocytes for development to the
blastocyst stage (P < or = 0.05) were prevented, at least in part, by
culturing oocytes in the presence of DTT (50 microM). Although the
mechanism by which DTT exerts its beneficial effects on aged oocytes
remains to be elucidated, it may protect oocytes by preventing oxidation of
free thiol groups and/or altering a redox-independent signalling pathway
that mediates cellular fragmentation and death.
相似文献
4.
Determination of the parent of origin in nine cases of prenatally detected chromosome aberrations found after intracytoplasmic sperm injection 总被引:1,自引:17,他引:1
Van Opstal D; Los FJ; Ramlakhan S; Van Hemel JO; Van Den Ouweland AM; Brandenburg H; Pieters MH; Verhoeff A; Vermeer MC; Dhont M; In't Veld PA 《Human reproduction (Oxford, England)》1997,12(4):682-686
Prenatal cytogenetic analysis of 71 fetuses conceived by intracytoplasmic
sperm injection (ICSI) resulted in the detection of nine (12.7%) chromosome
aberrations including two cases of 47,XXY, four cases involving a 45,X cell
line and three autosomal trisomies. Molecular analysis of the parental
origin of the deleted or supernumerary chromosome was performed by using
polymorphic microsatellite markers. Six cases involving a sex chromosome
abnormality were found to be of paternal origin while the two trisomic
cases that could be analysed were of maternal origin. Two cases involved
the same infertile couple who had two consecutive ICSI pregnancies
terminated because of a chromosome abnormality. The replaced embryos in
both cases originated from a single batch of ICSI fertilized oocytes of
which part was used to initiate the first pregnancy and part was
cryopreserved and used to initiate the second pregnancy.
相似文献
5.
Pirie FJ Pegoraro R Motala AA Rauff S Rom L Govender T Esterhuizen TM 《Tissue antigens》2005,66(2):125-130
Type 1 diabetes is the consequence of exposure of genetically susceptible individuals to specific environmental precipitants. The innate immune system provides the initial response to exogenous antigen and links with the adaptive immune system. The aim of this study was to assess the role of polymorphisms occurring in the cytoplasmic region of toll-like receptor (TLR) 3 gene and immediate 5' sequence, in subjects of Zulu descent with type 1 diabetes in KwaZulu-Natal, South Africa. Seventy-nine subjects with type 1 diabetes and 74 healthy normal glucose tolerant gender-matched control subjects were studied. Parts of exon 4 and exon 3/intron 3 of the TLR3 gene were studied by polymerase chain reaction, direct sequencing and restriction enzyme digestion with Bts 1. Of the nine polymorphisms studied, a significant association with type 1 diabetes was found for the major allele in the 2593 C/T polymorphism and for the minor alleles in the 2642 C/A and 2690 A/G polymorphisms, which were found to be in complete linkage disequilibrium. Correction of the P-values for the number of alleles studied, however, rendered the results no longer significant. These results suggest that polymorphisms in the TLR3 gene, which is part of the innate immune system, may be associated with type 1 diabetes in this population. 相似文献
6.
Pirie PL Stone EJ Assaf AR Flora JA Maschewsky-Schneider U 《Health education research》1994,9(1):23-36
Community-based programs are being widely adopted in the struggle to prevent chronic disease. Program evaluation of community-based programs involves a particular set of problems stemming from the variety of activities being undertaken simultaneously, the multiple intermediate goals of the programs and the rapidity with which the programs evolve. An analysis of the experience of four large community-based cardiovascular disease research and demonstration studies (Stanford Five-City Project, Minnesota Heart Health Program, Pawtucket Heart Health Program and the German Cardiovascular Prevention Project) provides valuable models, methodologies and strategies for planning and conducting evaluations of public health programs or community studies. By comparing and combining their experiences, the four programs have identified eight categories of evaluation for community studies, including formative evaluation, quality assurance, assessment of delivered dose, assessment of received dose, component program impact, intermediate outcomes, community impact and cost analysis. This paper presents information on the strategies by which each of the four programs addressed these evaluation categories. 相似文献
7.
Uribe Rivera FJ 《Cadernos de saúde pública / Ministério da Saúde, Funda??o Oswaldo Cruz, Escola Nacional de Saúde Pública》1996,12(3):357-372
In this paper, the organizational theory of situational planning is used to establish a decentralized management model for complex health units. Because of cultural limitations imposed on a perspective of change and rationalization, considerations are made in relation to a given form of dealing with culture, keeping in mind the feasibility of the management model. A particular type of communicative management emerges as a general need revealed by the analysis of the object at issue: the management of professional organizations. 相似文献
8.
9.
FJ Cowan JT Warner LM Lowes JP Riberio JW Gregory 《Archives of disease in childhood》1997,77(2):109-114
AIMS: To define outcome measures for auditing the clinical care of children and adolescents with insulin dependent diabetes mellitus (IDDM) and to assess the benefit of appointing a dedicated paediatric trained diabetes specialist nurse (PDSN). METHODS: Retrospective analysis of medical notes and hospital records. Glycaemic control, growth, weight gain, microvascular complications, school absence, and the proportion of children undergoing an annual clinical review and diabetes education session were assessed. The effect of the appointment of a PDSN on the frequency of hospital admission, length of inpatient stay, and outpatient attendance was evaluated. RESULTS: Children with IDDM were of normal height and grew well for three years after diagnosis, but grew suboptimally thereafter. Weight gain was above average every year after diagnosis. Glycaemic control was poor at all ages with only 16% of children having an acceptable glycated haemoglobin. Eighty five per cent of patients underwent a formal annual clinical review, of whom 16% had background retinopathy and 20% microalbuminuria in one or more samples. After appointing the PDSN the median length of hospital stay for newly diagnosed patients decreased from five days to one day, with 10 of 24 children not admitted. None of the latter was admitted during the next year. There was no evidence of the PDSN affecting the frequency of readmission or length of stay of children with established IDDM. Non-attendance at the outpatient clinic was reduced from a median of 19 to 10%. CONCLUSIONS: Outcome measures for evaluating the care of children with IDDM can be defined and evaluated. Specialist nursing support markedly reduces the length of hospital stay of newly diagnosed patients without sacrificing the quality of care. 相似文献
10.
FJ O'Callaghan AC Clarke H Joffe B Keeton R Martin A Salmon RD Thomas JP Osborne 《Archives of disease in childhood》1998,78(2):159-162
This report highlights the association between tuberous sclerosis and Wolff-Parkinson-White syndrome. Ten patients with concurrent diagnoses of Wolff-Parkinson-White syndrome and tuberous sclerosis were identified. Wolff-Parkinson-White syndrome presented early in life, nine cases being diagnosed in the first year. Eight of the 10 cases were male. In eight cases, the syndrome was associated with supraventricular tachycardias, and in nine with cardiac rhabdomyomata. One child died from cardiac failure secondary to obstruction of the left ventricular outflow tract by a rhabdomyoma. Five of nine survivors showed resolution of Wolff-Parkinson-White syndrome on follow up. The accessory pathway was localised in nine patients from surface electrocardiograms: six children had left sided pathways and three had right sided pathways. 相似文献