全文获取类型
收费全文 | 27096篇 |
免费 | 2693篇 |
国内免费 | 800篇 |
专业分类
耳鼻咽喉 | 115篇 |
儿科学 | 543篇 |
妇产科学 | 741篇 |
基础医学 | 5649篇 |
口腔科学 | 336篇 |
临床医学 | 2335篇 |
内科学 | 2870篇 |
皮肤病学 | 294篇 |
神经病学 | 1799篇 |
特种医学 | 395篇 |
外国民族医学 | 2篇 |
外科学 | 1074篇 |
综合类 | 5002篇 |
现状与发展 | 4篇 |
一般理论 | 11篇 |
预防医学 | 4504篇 |
眼科学 | 316篇 |
药学 | 1990篇 |
15篇 | |
中国医学 | 897篇 |
肿瘤学 | 1697篇 |
出版年
2024年 | 75篇 |
2023年 | 446篇 |
2022年 | 710篇 |
2021年 | 1061篇 |
2020年 | 1092篇 |
2019年 | 986篇 |
2018年 | 856篇 |
2017年 | 880篇 |
2016年 | 1020篇 |
2015年 | 1101篇 |
2014年 | 1861篇 |
2013年 | 2150篇 |
2012年 | 1705篇 |
2011年 | 1903篇 |
2010年 | 1505篇 |
2009年 | 1493篇 |
2008年 | 1557篇 |
2007年 | 1346篇 |
2006年 | 1301篇 |
2005年 | 1029篇 |
2004年 | 893篇 |
2003年 | 810篇 |
2002年 | 656篇 |
2001年 | 513篇 |
2000年 | 401篇 |
1999年 | 326篇 |
1998年 | 341篇 |
1997年 | 306篇 |
1996年 | 263篇 |
1995年 | 242篇 |
1994年 | 171篇 |
1993年 | 149篇 |
1992年 | 156篇 |
1991年 | 131篇 |
1990年 | 107篇 |
1989年 | 113篇 |
1988年 | 96篇 |
1987年 | 102篇 |
1986年 | 94篇 |
1985年 | 107篇 |
1984年 | 87篇 |
1983年 | 84篇 |
1982年 | 69篇 |
1981年 | 78篇 |
1980年 | 72篇 |
1979年 | 48篇 |
1978年 | 32篇 |
1977年 | 12篇 |
1976年 | 22篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Intraperitoneal infection with Salmonella abortusovis is partially controlled by a gene closely linked with the Ity gene.
下载免费PDF全文
![点击此处可从《Clinical and experimental immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
I P Oswald F Lantier R Moutier M F Bertrand E Skamene 《Clinical and experimental immunology》1992,87(3):373-378
The aim of the present study was to determine whether the Ity gene, which controls the resistance to S. typhimurium infection in mice, also governs the resistance to S. abortusovis, a serotype specific for goat and sheep. During either i.v. or i.p. infection, BALB/c mice (Itys) were not able to control the growth of S. abortusovis and eventually died from infection. In contrast CBA (Ityr) or (C.CB)F1 (Ityr/s) mice were able to control the growth of these bacteria. Using congenic C.D2 Ityr mice, we found that the gene controlling resistance to S. abortusovis was tightly linked to the Ity gene on chromosome 1. Furthermore, in the spleen and the liver of backcross BALB/c x (CBA x BALB/c) mice, the S. abortusovis resistance phenotype cosegregated with the two alleles of the Len-1 gene, a gene tightly linked to the Ity gene. By contrast, in these backcross mice, the level of infection of the peritoneal cavity, the site of inoculation, did not correlated with the Len-1 phenotype of the animal. These results provide evidence that after i.p. inoculation the control of S. abortusovis growth in the spleen and the liver is controlled by the Ity gene, but also suggest that additional gene(s) regulate the number of bacteria at the site of inoculation. 相似文献
102.
Numerical comparisons of two formulations of the logistic regressive models with the mixed model in segregation analysis of discrete traits. 总被引:4,自引:0,他引:4
Segregation analysis of discrete traits can be conducted by the classical mixed model and the recently introduced regressive models. The mixed model assumes an underlying liability to the disease, to which a major gene, a multifactorial component, and random environment contribute independently. Affected persons have a liability exceeding a threshold. The regressive logistic models assume that the logarithm of the odds of being affected is a linear function of major genotype effects, the phenotypes of older relatives, and other covariates. A formulation of the regressive models, based on an underlying liability model, has been recently proposed. The regression coefficients on antecedents are expressed in terms of the relevant familial correlations and a one-to-one correspondence with the parameters of the mixed model can thus be established. Computer simulations are conducted to evaluate the fit of the two formulations of the regressive models to the mixed model on nuclear families. The two forms of the class D regressive model provide a good fit to a generated mixed model, in terms of both hypothesis testing and parameter estimation. The simpler class A regressive model, which assumes that the outcomes of children depend solely on the outcomes of parents, is not robust against a sib-sib correlation exceeding that specified by the model, emphasizing testing class A against class D. The studies reported here show that if the true state of nature is that described by the mixed model, then a regressive model will do just as well. Moreover, the regressive models, allowing for more patterns of family dependence, provide a flexible framework to understand gene-environment interactions in complex diseases. 相似文献
103.
Detection of linkage under heterogeneity: comparison of the two-locus vs. admixture models. 总被引:9,自引:0,他引:9
L R Goldin 《Genetic epidemiology》1992,9(1):61-66
Linkage analysis under the two-locus model and the admixture model was compared on pedigree data for a common disease stimulated under a model of genetic heterogeneity. The ascertainment of families was designed so that the samples had a large proportion of families segregating for both disease loci. The two-locus linkage analysis model did not demonstrate increased power of detecting linkage or more accurate estimates of the recombination fraction, theta than did the admixture model linkage analysis. When a sample was purposely chosen so that all of the families were segregating for both loci, then the two-locus lod score analysis was better. However, the increased power depended on assuming the correct gene frequency for the linked locus. It can be concluded that under the conditions of genetic heterogeneity examined here, testing for linkage under the admixture model is the preferred method of analysis. However, this is not a general conclusion that can apply to all two-locus disease models. 相似文献
104.
While the season-of-birth effect is one of the most consistent epidemiological features of schizophrenia, there is a lack
of consistency with respect to the interaction between season of birth and family history of schizophrenia. Apart from family
history, measures related to consanguinity can be used as proxy markers of genomic heterogeneity. Thus, these measures may
provide an alternate, indirect index of genetic susceptibility. We had the opportunity to explore the interaction between
season of birth and measure of consanguinity in well-described genetic isolates in Daghestan, some of which are known for
their relatively high prevalence of schizophrenia. Our previous population-genetic study showed Daghestan has an extremely
high genetic diversity between the ethnic populations and a low genetic diversity within them. The isolates selected for this
study include some with more than 200 and some with less than 100 generations of demographical history since their founding.
Based on pedigrees of multiply-affected families, we found that among individuals with schizophrenia, the measure of consanguinity
was significantly higher in the parents of those born in winter/spring compared to those born in summer/autumn. Furthermore,
compared to summer/autumn born, winter/spring born individuals with schizophrenia had an earlier age-of-onset, and more prominent
auditory hallucinations. Our results suggest that the offspring of consanguineous marriages, and thus those with reduced allelic
heterogeneity, may be more susceptible to the environmental factor(s) underpinning the season-of-the effect in schizophrenia. 相似文献
105.
弱激光血疗法的发展及展望 总被引:3,自引:1,他引:2
本文主要介绍了弱激光血疗的机制及其在我国的发展过程.弱激光血疗法起源于前苏联的紫外光量子疗法,传入我国后经历了静脉内照射疗法,离体血液激光照射回输疗法,口咽部照射伴吸氧疗法,鼻腔内照射疗法等.本文对各种疗法的特点及临床应用进行了详细叙述.有些学者认为,中医的观点也能揭示激光血疗的机制.从中医辨证的角度,人的体质分为虚证和实证.结合中医针灸的虚则补之,实则泻之的原理,根据患者的虚实状况,采用含有中医补泻信息的调制激光照射血液,同时加照相关敏感穴位,促进疗效,以体现中医的辨证施治的原则可取得更好的疗效. 相似文献
106.
To find out if patients with contact allergy are helped by computerized information lists, a retrospective study was carried out on 58 patients with contact allergy to lanolin, traced through our local database DALUK. All were sent a questionnaire about their usage of the information list, clearance of their eczema, their education and other details. Clearance of the patient's eczema was found to correlate with use of the information list. It was also found that the effectiveness of the information depended on factors such as education, family circumstances, ethnic background and, most of all, how and where the information list was used. 相似文献
107.
利用乙型肝炎病毒DNA开放框架上的BamHI和HpaI位点,酶切消化质粒载体PEcob6(含双拷贝HBVDNA),得到约900bp的HBV-S基因片断。将其插入到噬菌粒载体PBluescriptsk+的SmaI位点上。然后通过体外寡核苷酸介导的人工定点突变获得一系列(共12种)S基因“免疫逃避”突变型。再通过EB病毒真核表达载体pMEP4上的BamHI和Kpnl位点将噬菌粒pBluescripsk+上的S基因突变型片断定向克隆到PMEP4上,从而构建了含乙肝S基因突变型的重组质粒pMEP4HBSM。用其转染人肝癌传代细胞系HepG2,经潮霉素选择,三周后获得抗性细胞克隆。经用抗HBs单克隆抗体(含针对HBsAg“a”抗原决定簇)检测除含变异体145(即145位上甘氨酸为精氨酸替代)外其余抗变异体HBsAg均为阳性。经Westernblot证实变异体145,在分子量约为23KD处有一特异HBsAg蛋白带。 相似文献
108.
SNP及其在畜牧业中的应用前景 总被引:4,自引:0,他引:4
张利平 《国外畜牧学(草食家畜)》2003,(3):30-32
SNP(single nucleotide polymorphisns-单核苷酸多态性)是继限制性片段长度多态性和微卫星之后,新发展起来的第3代分子标记。已成为一类新的遗传标记,广泛应用于基因定位、克隆和遗传多样性研究。本文介绍了SNP的特性、检测方法及其在畜牧业研究生产中的广泛利用前景。并提出了SNP研究中遇到的一些问题。 相似文献
109.
T. Iwanaga †‡ A. McEuen† A. F. Walls† J. B. Clough† T. P. Keith§ S. Rorke† S. J. Barton† S. T. Holgate† J. W. Holloway † 《Clinical and experimental allergy》2004,34(7):1037-1042
BACKGROUND: Mast cell chymase has the potential to be an important mediator of inflammation and remodelling in the asthmatic lung. Previous studies have examined association between promoter polymorphism of the chymase gene (CMA1) and allergic phenotypes but the significance of this polymorphism is unclear. We have examined association of a CMA1 variant in relation to asthma in a large UK Caucasian family cohort. METHODS: A polymorphism of the CMA1 gene promoter (-1903G/A) was genotyped in 341 asthmatic families and in 184 non-asthmatic adults recruited from the UK PCR-RFLP based genotyping. Association with asthma diagnosis, atopy, specific and total IgE, and atopy and asthma severity was examined. RESULTS: Case-control studies did not reveal a significant difference in allele frequency between asthmatics and controls. A significant association was found between CMA1 genotypes and total IgE levels in subjects with self-reported eczema that remained significant after correction for multiple testing (median total serum IgE GG 297 kU/L, GA 144 kU/L, AA 48.4 kU/L, Pc=0.0032). CONCLUSION: These data suggest that CMA1 promoter polymorphism does not contribute to asthma susceptibility or severity but may be involved in regulating IgE levels in patients with eczema. 相似文献
110.
Lorraine N Clark Eneli Haamer Helen Mejia-Santana Juliette Harris Suzanne Lesage Alexandra Durr Sabine Janin Bs Katja Hedrich Elan D Louis Lucien J Cote Howard Andrews Stanley Fahn Cheryl Waters Blair Ford Steven Frucht William Scott Christine Klein Alexis Brice Hanno Roomere Ruth Ottman Karen Marder 《Movement disorders》2007,22(7):932-937
Parkin mutations account for the majority of familial and sporadic early onset Parkinson's disease (EOPD) cases with a known genetic association. More than 100 mutations have been described in the Parkin gene that includes homozygous, compound heterozygous, and single heterozygous mutations. We have designed a Parkin mutation genotyping array (gene chip) that includes published Parkin sequence variants and allows their simultaneous detection. The chip was validated by screening 85 PD cases and 47 controls previously tested for Parkin mutations. Similar genotyping microarrays have been developed for other genetically heterogeneous diseases including age-related macular degeneration. Here, we show the utility of a genotyping array for Parkinson's disease by analysis of 60 subjects from the Genetic Epidemiology of Parkinson Disease (GEPD) study that includes 15 early-onset PD case probands and 45 relatives. 相似文献