全文获取类型
收费全文 | 1328篇 |
免费 | 70篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 45篇 |
妇产科学 | 7篇 |
基础医学 | 116篇 |
口腔科学 | 33篇 |
临床医学 | 194篇 |
内科学 | 329篇 |
皮肤病学 | 15篇 |
神经病学 | 183篇 |
特种医学 | 153篇 |
外科学 | 120篇 |
综合类 | 30篇 |
预防医学 | 41篇 |
眼科学 | 11篇 |
药学 | 100篇 |
中国医学 | 7篇 |
肿瘤学 | 52篇 |
出版年
2020年 | 10篇 |
2019年 | 12篇 |
2018年 | 16篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 36篇 |
2012年 | 29篇 |
2011年 | 32篇 |
2010年 | 46篇 |
2009年 | 45篇 |
2008年 | 44篇 |
2007年 | 77篇 |
2006年 | 42篇 |
2005年 | 33篇 |
2004年 | 33篇 |
2003年 | 29篇 |
2002年 | 27篇 |
2001年 | 31篇 |
2000年 | 34篇 |
1999年 | 33篇 |
1998年 | 50篇 |
1997年 | 39篇 |
1996年 | 42篇 |
1995年 | 30篇 |
1994年 | 19篇 |
1993年 | 29篇 |
1992年 | 30篇 |
1991年 | 31篇 |
1990年 | 31篇 |
1989年 | 42篇 |
1988年 | 58篇 |
1987年 | 37篇 |
1986年 | 34篇 |
1985年 | 25篇 |
1984年 | 20篇 |
1983年 | 22篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 23篇 |
1977年 | 20篇 |
1976年 | 23篇 |
1975年 | 20篇 |
1974年 | 16篇 |
1973年 | 12篇 |
1972年 | 12篇 |
1971年 | 10篇 |
1968年 | 11篇 |
排序方式: 共有1444条查询结果,搜索用时 78 毫秒
11.
12.
The P-selectin gene is highly polymorphic: reduced frequency of the Pro715 allele carriers in patients with myocardial infarction 总被引:10,自引:3,他引:10
Herrmann SM; Ricard S; Nicaud V; Mallet C; Evans A; Ruidavets JB; Arveiler D; Luc G; Cambien F 《Human molecular genetics》1998,7(8):1277-1284
P-selectin is an adhesion molecule, expressed at the surface of activated
cells, that mediates the interaction of activated endothelial cells or
platelets with leukocytes. P-selectin expression is increased in
atherosclerotic plaques, and high plasma levels of this molecule have been
observed in patients with unstable angina. We investigated the P-selectin
gene as a possible candidate for myocardial infarction (MI). The P-selectin
gene is situated on chromosome 1q21-q24, spans >50 kb and contains 17
exons. The sequences of the 5'-flanking region and exons of 40 alleles from
patients with MI were screened for polymorphisms using polymerase chain
reaction/single-strand conformation polymorphism (PCR-SSCP) and sequencing.
Thirteen polymorphisms were identified: five in the 5'-flanking and eight
in the exonic sequences. Four polymorphisms (Ser290Asn, Asn562Asp,
Leu599Val and Thr715Pro) predicted a change in the amino acid sequence of
the P- selectin protein. All P-selectin polymorphisms as well as a common
E- selectin polymorphism, Ser128Arg which has been reported as being
associated with an increased risk of premature coronary heart disease
(CHD), and is in tight linkage disequilibrium with several P-selectin
polymorphisms, were investigated in 647 patients with MI and 758 control
subjects from four regions of France and Northern Ireland (the ECTIM
study). The entire set of P-selectin polymorphisms provided a
heterozygosity of 91%. The polymorphisms were tightly associated with one
another and displayed patterns of linkage disequilibrium suggesting the
existence of highly conserved ancestral haplotypes. The five polymorphisms
in the 5'-flanking region of the gene were unrelated to MI or any relevant
phenotype measured in the ECTIM study. We inferred that the four missense
variants identified in the coding region predicted eight common forms of
the P-selectin protein. The Pro715 allele which characterizes one of these
forms was less frequent in France than in Northern Ireland ( P < 0.002)
and in cases than in controls ( P < 0.002; P < 0.02 after correction
for the number of tests). We conclude that the P-selectin gene is highly
polymorphic and hypothesize that the Pro715 variant may be protective for
MI. Whether this variant affects the properties of the P-selectin protein
in a way which is compatible with this hypothesis needs to be checked
experimentally.
相似文献
13.
Sperm quality in Hodgkin's disease versus non-Hodgkin's lymphoma 总被引:3,自引:4,他引:3
Botchan A; Hauser R; Gamzu R; Yogev L; Lessing JB; Paz G; Yavetz H 《Human reproduction (Oxford, England)》1997,12(1):73-76
The study was conducted to determine the deleterious effect of lymphoma
disease on spermatogenesis and to evaluate the possibility that the disease
is mediated primarily by inherent mechanisms in Hodgkin's disease and
non-Hodgkin's lymphoma patients. A total of 89 patients with lymphoma
disease (Hodgkin's and non-Hodgkin's) were referred for sperm preservation
prior to adjuvant treatments. A comparison was made of pre- and post-thaw
sperm quality between lymphoma patients and healthy volunteers who applied
for sperm donation. This was followed by further assessment of the
differences between patients with Hodgkin's disease and non-Hodgkin's
lymphoma in terms of sperm variables, clinical parameters and blood hormone
concentrations. It was found that patients with lymphoma disease had
significantly impaired pre-freeze and post-thaw sperm quality compared with
that of healthy volunteers. Patients with non-Hodgkin's lymphoma had
spermatozoa of higher quality than patients with Hodgkin's disease. No
differences were found in the clinical or hormonal parameters between these
two groups. As expected, reduced testicular size and abnormal testicular
consistency were correlated with decreased sperm quality. The mere presence
of cancer disease has a direct negative effect on spermatogenesis, which is
probably not related to incidental side-effects. A variable degree of
impairment should be expected with different categories of cancer.
相似文献
14.
15.
Five haplotypes account for fifty-five percent of ATM mutations in Brazilian patients with ataxia telangiectasia: seven new mutations 总被引:7,自引:0,他引:7
Coutinho G Mitui M Campbell C Costa Carvalho BT Nahas S Sun X Huo Y Lai CH Thorstenson Y Tanouye R Raskin S Kim CA Llerena J Gatti RA 《American journal of medical genetics. Part A》2004,(1):33-40
We have studied the molecular genetics of 27 Brazilian families with ataxia telangiectasia (AT). Five founder effect haplotypes accounted for 55.5% of the families. AT is an autosomal recessive disorder of childhood onset characterized by progressive cerebellar ataxia, ocular apraxia, telangiectasia, immunodeficiency, radiation sensitivity, chromosomal instability, and predisposition to cancer. The ATM gene spans more than 150 kb on chromosome region 11q23.1 and encodes a product of 3056 amino acids. The ATM protein is a member of the phosphatidylinositol 3-kinase (PI-3K) family of proteins and is involved in cell cycle control and DNA repair pathways. DNA was isolated from lymphoblastoid cell lines and haplotyped using four STR markers (D11S1818, NS22, D11S2179, D11S1819) within and flanking the ATM gene; all allele sizes were standardized in advance. In addition to the STR haplotypes, SNP haplotypes were determined using 10 critical polymorphisms. The entire gene was screened sequentially by protein truncation testing (PTT), single strand conformation polymorphism (SSCP), and then denaturing high performance liquid chromatography (dHPLC) to identify the disease-causing mutations. Of the expected 54 mutations, 50 were identified. All mutations but one, led to a truncated or null form of the ATM protein (nonsense, splice site, or frameshift). Five families (18.5%) carried a deletion of 3450nt (from IVS28 to Ex31), making this one of the two most common Brazilian mutations. Mutations were located throughout the entire gene, with no clustering or hotspots. Standardized STR haplotype analysis greatly enhanced the efficiency of mutation screening. 相似文献
16.
O'Neill P Trombley L Gundel M Hunter T Nicklas JA Ferreira ML Bugallo MJ Farias AC Lohr A Diamantopoulos M Raskin S 《Arquivos de neuro-psiquiatria》1999,57(4):907-911
The mutation in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene has been determined in two brothers affected with Lesch-Nyhan syndrome. Female members of the family who are at risk for being heterozygous carriers of the HPRT mutation were also studied to determine whether they carry the mutation. DNA sequencing revealed that the boys' mother is heterozygous for the mutation in her somatic cells, but that three maternal aunts are not heterozygous. Such carrier information is important for the future pregnancy plans of at-risk females. The mutation, an A-->T transversion at cDNA base 590 (590A-->T), results in an amino acid change of glutamic acid to valine at codon 197, and has not been reported previously in a Lesch-Nyhan syndrome male. This mutation is designated HPRTBrasil. 相似文献
17.
Distal radius fractures commonly are sustained by athletes during competition. Typically, these are high energy injuries with severe displacement, metaphyseal comminution, and articular surface disruption. Each fracture is distinguished by its degree of articular displacement, stability, and reducibility. Management is contingent on recognition of the variable magnitude of articular disruption and skillful treatment based on specific fracture configuration. 相似文献
18.
Weintraub D Raskin A Ruskin PE Gruber-Baldini AL Zimmerman SI Hebel JR German P Magaziner J 《Psychiatric services (Washington, D.C.)》2000,51(10):1259-1264
OBJECTIVE: The purpose of this study was to determine the prevalence of dementia among black and white residents on admission to nursing homes and to determine whether demographic and health characteristics known to be associated with dementia were correlated with dementia in this population. METHODS: Data from medical records and structured interviews with family members, nursing staff, and nursing home residents were gathered for 2,285 persons newly admitted to nursing homes in Maryland from 1992 to 1995. A stratified sample of 59 nursing homes was used. An expert panel of five physicians classified each resident as demented, nondemented, or indeterminate. Associations between dementia status, race, and selected characteristics were examined. RESULTS: Black residents (77 percent) were significantly more likely than white residents (57 percent) to be classified as demented. Older age was associated with dementia in both races. Less education, male gender, and a history of a cerebrovascular accident were associated with an increased prevalence of dementia among white residents only. After demographic and health characteristics associated with dementia were controlled for, black race remained independently associated with a diagnosis of dementia. CONCLUSIONS: The rate of dementia on admission to nursing homes was higher among black residents than among white residents, a finding that has implications for the delivery of care. The higher rate may be due to psychosocial factors operating differently in blacks and whites that influence the timing of admission to a nursing home. 相似文献
19.