全文获取类型
收费全文 | 45319篇 |
免费 | 3434篇 |
国内免费 | 125篇 |
专业分类
耳鼻咽喉 | 361篇 |
儿科学 | 1904篇 |
妇产科学 | 1366篇 |
基础医学 | 5949篇 |
口腔科学 | 710篇 |
临床医学 | 5229篇 |
内科学 | 8666篇 |
皮肤病学 | 865篇 |
神经病学 | 4949篇 |
特种医学 | 938篇 |
外国民族医学 | 3篇 |
外科学 | 4842篇 |
综合类 | 503篇 |
现状与发展 | 1篇 |
一般理论 | 79篇 |
预防医学 | 5683篇 |
眼科学 | 753篇 |
药学 | 2975篇 |
中国医学 | 75篇 |
肿瘤学 | 3027篇 |
出版年
2024年 | 89篇 |
2023年 | 711篇 |
2022年 | 1205篇 |
2021年 | 2340篇 |
2020年 | 1383篇 |
2019年 | 1975篇 |
2018年 | 2274篇 |
2017年 | 1483篇 |
2016年 | 1641篇 |
2015年 | 1736篇 |
2014年 | 2288篇 |
2013年 | 2838篇 |
2012年 | 4169篇 |
2011年 | 4011篇 |
2010年 | 2038篇 |
2009年 | 1729篇 |
2008年 | 2682篇 |
2007年 | 2695篇 |
2006年 | 2329篇 |
2005年 | 2156篇 |
2004年 | 1837篇 |
2003年 | 1522篇 |
2002年 | 1351篇 |
2001年 | 208篇 |
2000年 | 156篇 |
1999年 | 219篇 |
1998年 | 251篇 |
1997年 | 156篇 |
1996年 | 138篇 |
1995年 | 131篇 |
1994年 | 126篇 |
1993年 | 109篇 |
1992年 | 75篇 |
1991年 | 81篇 |
1990年 | 59篇 |
1989年 | 55篇 |
1988年 | 44篇 |
1987年 | 47篇 |
1986年 | 44篇 |
1985年 | 48篇 |
1984年 | 47篇 |
1983年 | 36篇 |
1982年 | 37篇 |
1981年 | 36篇 |
1980年 | 41篇 |
1979年 | 32篇 |
1978年 | 29篇 |
1977年 | 17篇 |
1974年 | 23篇 |
1972年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Upregulation of TGF-beta, FOXP3, and CD4+CD25+ regulatory T cells correlates with more rapid parasite growth in human malaria infection 总被引:8,自引:0,他引:8
Walther M Tongren JE Andrews L Korbel D King E Fletcher H Andersen RF Bejon P Thompson F Dunachie SJ Edele F de Souza JB Sinden RE Gilbert SC Riley EM Hill AV 《Immunity》2005,23(3):287-296
Understanding the regulation of immune responses is central for control of autoimmune and infectious disease. In murine models of autoimmunity and chronic inflammatory disease, potent regulatory T lymphocytes have recently been characterized. Despite an explosion of interest in these cells, their relevance to human disease has been uncertain. In a longitudinal study of malaria sporozoite infection via the natural route, we provide evidence that regulatory T cells have modifying effects on blood-stage infection in vivo in humans. Cells with the characteristics of regulatory T cells are rapidly induced following blood-stage infection and are associated with a burst of TGF-beta production, decreased proinflammatory cytokine production, and decreased antigen-specific immune responses. Both the production of TGF-beta and the presence of CD4+CD25+FOXP3+ regulatory T cells are associated with higher rates of parasite growth in vivo. P. falciparum-mediated induction of regulatory T cells may represent a parasite-specific virulence factor. 相似文献
72.
Turrisi R Hillhouse J Heavin S Robinson J Adams M Berry J 《Journal of behavioral medicine》2004,27(4):393-412
The research evaluated an intervention strategy designed to prevent skin cancer in young adolescents. The intervention used parents as change agents to effectively communicate the risks of skin cancer and encourage their children to avoid high-risk sun-related behaviors while increasing positive sun-safe behaviors. Three hundred and forty parents in two regions of the United States were educated about the dangers of risky sun behaviors and how to convey information about skin cancer prevention to their children. Parents were then encouraged to talk with their children about these issues over a 1-month period prior to the onset of summer. Following this time period, children whose parents received and implemented the intervention materials were compared with a control sample of 129 children. These two groups were matched on age, gender, and school on number of sunburns and sunburn severity, attitudes and beliefs, and sunbathing behavior. Children in the treatment condition differed significantly from controls in the predicted directions on all outcome variables. The findings are discussed in terms of reducing skin cancer risk behaviors of children via parent-based intervention approaches. 相似文献
73.
Analysis of the Virus Population Present in Equine Faeces Indicates the Presence of Hundreds of Uncharacterized Virus Genomes 总被引:7,自引:0,他引:7
Virus DNA was isolated from horse faeces and cloned in a sequence-independent fashion. 268 clones were sequenced and 178140 nucleotides of sequence obtained. Statistical analysis suggests the library contains 17560 distinct clones derived from up to 233 different virus genomes. TBLASTX analysis showed that 32% of the clones had significant identity to GenBank entries. Of these 63% were viral; 20% bacterial; 7% archaeal; 6% eukarya; and 5% were related to mobile genetic elements. Fifty-two percent of the virus identities were with Siphoviridae; 26% unclassified phages; 17% Myoviridae; 4% Podoviridae; and one clone (2%) was a vertebrate Orthopoxvirus. Genes coding for predicted virus structural proteins, proteases, glycosidases and nucleic acid-binding proteins were common. 相似文献
74.
Casey Graham; Plummer Sarah; Hoeltge Gerald; Scanlon David; Fasching Clare; Stanbridge Eric J. 《Human molecular genetics》1993,2(11):1921-1927
Rearrangements or deletions of chromosome 17 are the most frequentlyobserved genetic changes identified in breast tumors. Molecularanalyses suggest that in addition to the p53 gene on 17p13.1there may be at least three other tumor suppressor genes onchromosome 17 involved in breast cancer. Regions of loss ofheterozygosity (LOH) identified on 17p13.3 and 17q12-qter occurfrequently in breast tumors, and the BRCA-1 gene has been mappedto 17q21 by genetic linkage analysis. Here we provide biologicalevidence for the presence of a growth suppressor gene(s) onchromosome 17 that results In the In vitro growth suppressionof the p53 wild-type MCF 7 breast cancer cell line. We haveIntroduced a normal chromosome 17 into MCF 7 cells by microcellmediatedchromosome transfer (MMCT), and demonstrate that cells growtharrest before 10 to 12 population doublings. In contrast, theintroduction of a normal chromosome 13 had no effect upon growthof these cells either In vitro or In vivo. These data providedirect functional evidence for the presence of a growth suppressorgene(s) on chromosome 17, which is not p53, and which may representone of several gene(s) that play a critical role in the developmentof breast cancer. 相似文献
75.
76.
Margaret O''Dougherty Gary G. Berntson Sarah T. Boysen Francis S. Wright Douglas Teske 《Psychophysiology》1988,25(3):305-315
Cardiac responses to non-signal stimuli and to signal stimuli in a vigilance task were examined in children born with congenital heart defects (CHD), and in normal and attention deficit disordered (ADD) subjects. Overall task performance was lower in subjects with heart defects and in the ADD group. Cardiac measures revealed that normal children displayed significantly larger heart rate deceleration to the target stimuli than did either of the clinical groups. Moreover, although no group differences were observed in the cardiac response to non-signal auditory stimuli, exaggerated heart rate deceleration was observed to vibrotactile stimuli in both the clinical groups. Regression analyses revealed that the magnitude of the cardiac response to somatosensory stimuli was predictive of task performance (both within and between subject groups), with larger responses associated with higher error rates and lower perceptual sensitivity. Results were suggestive of a predictive relationship between somatosensory reactivity and neuropsychological maturation. 相似文献
77.
A patient with the clinical stigmata of gonadal dysgenesis is presented. Cytogenetic investigations revealed two distinct structural chromosome rearrangements. One of these, an isochromosome for the long arm of the X, proved to be a dicentric element following C-banding. The second abnormality, an inherited familial marker, was a pericentric inversion of No. 2 [(inv 2) (p15q21)]. 相似文献
78.
Sarah J Spence Rita M Cantor Lien Chung Sharon Kim Daniel H Geschwind Maricela Alarcón 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(6):591-598
The identification of autism susceptibility genes has been hampered by phenotypic heterogeneity of autism, among other factors. However, the use of endophenotypes has shown preliminary success in reducing heterogeneity and identifying potential autism-related susceptibility regions. To further explore the utility of using language-related endophenotypes, we performed linkage analysis on multiplex autism families stratified according to delayed expressive speech and also assessed the extent to which parental phenotype information would aid in identifying regions of linkage. A whole genome scan using a multipoint non-parametric linkage approach was performed in 133 families, stratifying the sample by phrase speech delay and word delay (WD). None of the regions reached suggested genome-wide or replication significance thresholds. However, several loci on chromosomes 1, 2, 4, 6, 7, 8, 9, 10, 12, 15, and 19 yielded nominally higher linkage signals in the delayed groups. The results did not support reported linkage findings for loci on chromosomes 7 or 13 that were a result of stratification based on the language delay endophenotype. In addition, inclusion of information on parental history of language delay did not appreciably affect the linkage results. The nominal increase in NPL scores across several regions using language delay endophenotypes for stratification suggests that this strategy may be useful in attenuating heterogeneity. However, the inconsistencies in regions identified across studies highlight the importance of increasing sample sizes to provide adequate power to test replications in independent samples. 相似文献
79.
Batt SL Charalambous BM McHugh TD Martin S Gillespie SH 《Journal of clinical microbiology》2005,43(6):2656-2661
Serotyping Streptococcus pneumoniae is a technique generally confined to reference laboratories, as purchasing pneumococcal antisera is a huge investment. Many attempts have been made to modify serological agglutination techniques to make them more accessible, and more recently developments in serotyping have focused on molecular techniques. This paper describes a PCR assay which amplifies the entire capsulation locus between dexB and aliA. Amplicons are digested to produce serotype-specific patterns. We have shown, using 81 epidemiologically unrelated strains representing 46 different serotypes, that the patterns correlate with a 90 to 100% similarity range for the same serotype or serogroup. Prospective testing of 73 isolates of unknown serotype confirmed reliable serotype attribution, and serotype profiles are reproducible on repeated testing. Once our database contains all 90 serotypes, this technique should be fully portable, cost-effective, and useful in any laboratory with sufficient molecular experience. 相似文献
80.