全文获取类型
收费全文 | 8028篇 |
免费 | 438篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 179篇 |
妇产科学 | 210篇 |
基础医学 | 1108篇 |
口腔科学 | 164篇 |
临床医学 | 712篇 |
内科学 | 2020篇 |
皮肤病学 | 98篇 |
神经病学 | 763篇 |
特种医学 | 208篇 |
外科学 | 1385篇 |
综合类 | 43篇 |
一般理论 | 2篇 |
预防医学 | 264篇 |
眼科学 | 112篇 |
药学 | 467篇 |
1篇 | |
中国医学 | 13篇 |
肿瘤学 | 685篇 |
出版年
2024年 | 8篇 |
2023年 | 75篇 |
2022年 | 131篇 |
2021年 | 256篇 |
2020年 | 149篇 |
2019年 | 204篇 |
2018年 | 198篇 |
2017年 | 128篇 |
2016年 | 197篇 |
2015年 | 248篇 |
2014年 | 358篇 |
2013年 | 377篇 |
2012年 | 586篇 |
2011年 | 622篇 |
2010年 | 365篇 |
2009年 | 299篇 |
2008年 | 556篇 |
2007年 | 617篇 |
2006年 | 520篇 |
2005年 | 497篇 |
2004年 | 476篇 |
2003年 | 421篇 |
2002年 | 357篇 |
2001年 | 56篇 |
2000年 | 37篇 |
1999年 | 68篇 |
1998年 | 78篇 |
1997年 | 64篇 |
1996年 | 60篇 |
1995年 | 61篇 |
1994年 | 57篇 |
1993年 | 45篇 |
1992年 | 39篇 |
1991年 | 35篇 |
1990年 | 23篇 |
1989年 | 22篇 |
1988年 | 11篇 |
1987年 | 18篇 |
1986年 | 23篇 |
1985年 | 21篇 |
1984年 | 22篇 |
1983年 | 18篇 |
1982年 | 16篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1977年 | 5篇 |
1975年 | 9篇 |
1974年 | 5篇 |
1966年 | 5篇 |
1908年 | 5篇 |
排序方式: 共有8523条查询结果,搜索用时 15 毫秒
51.
Cavalli E Mattasoglio A Pinciroli F Spaggiari P 《International journal of medical informatics》2004,73(3):297-303
In recent years, major and widely accepted information security understandings and achievements confirm that the problem is complex. They clarify that technologies are fundamental tools, but management processes have even bigger relevance, as also prestigious international magazines dossier clearly explained recently. Such a magazine attention outlines the wide impact that the subject has on watchful decision makers. ISO17799 is an emerging standard in information security. In principle there are no reasons for considering it not applicable to the health care sector. In practice, because of both the just conceptual level of the standard and the peculiarities of the health care data and institutions, a lot of analysis and design work need to be invested any time a health care institution decides to deal with the subject. CEN/ENV 12924 is another emerging standard certainly more on the spot of the health care. Nevertheless, it also asks for evident further investigation. The practical case of information security design, implementation, management, and auditing inside a multi-specialty provincial Italian hospital will be described. 相似文献
52.
53.
Cusin C Serretti A Lattuada E Lilli R Lorenzi C Smeraldi E 《American journal of medical genetics》2002,114(4):380-390
The aim of our study was to investigate a possible influence of monoamine oxydase A (MAO-A), catechol-O-methyltransferase (COMT), serotonin receptor 2A (5-HT2A), dopamine receptor D2 (DRD2), and dopamine receptor D4 (DRD4) gene variants on timing of recurrence in mood disorders. Gene variants were determined using PCR-based techniques in 550 inpatients affected by recurrent mood disorders (major depressives: n = 212; bipolars: n = 338), rapid cycling mood disorder (n = 81), and 663 controls. We investigated possible genetic influences by comparing illness time course of subjects subdivided according to genotype using multivariate analysis of variance (MANOVA). We could not observe a significantly different time course. No demographic and clinical variables such as sex, age or polarity of onset, presence of psychotic features, genetic loading, or education level influenced the observed results. Our results suggest that MAO-A, COMT, 5-HT2A, DRD2, and DRD4 gene variants are not involved in susceptibility toward different time courses in mood disorders. 相似文献
54.
Christina Brahe Stefania Zappata Isabella Velon Enrico Bertini Serenella Servidei Pietro Tonali Giovanni Neri 《American journal of medical genetics. Part A》1993,45(3):408-411
Linkage analysis and prenatal prediction in families segregating autosomal recessive spinal muscular atrophy (SMA) has become feasible since the assignment of the locus responsible for type I-III SMA to region 5q12-q13.3. We have performed a segregation study of SMA in Italian families using molecular probes and highly informative PCR-based polymorphic markers. In one family, a 7-year-old boy affected with type III SMA and an 8-year-old apparently healthy brother had identical haplotypes. These findings prompted us to reexamine the apparently unaffected child. His neurological exam was normal. However, the electromyography (EMG) showed a pattern consistent with chronic SMA. To our knowledge this is the first example of presymptomatic diagnosis of SMA based on genotype analysis. © 1993 Wiley-Liss, Inc. 相似文献
55.
Delia D Piane M Buscemi G Savio C Palmeri S Lulli P Carlessi L Fontanella E Chessa L 《Human molecular genetics》2004,13(18):2155-2163
Hypomorphic mutations of the MRE11 gene are the hallmark of the radiosensitive ataxia-telangiectasia-like disorder (ATLD). Here, we describe a new family with two affected siblings, ATLD5 and ATLD6, now aged 37 and 36, respectively. They presented with late onset cerebellar degeneration slowly progressing until puberty and absence of telangiectasias, and were cancer-free. Both patients were wild-type for ATM and NBS1, but compound heterozygotes for MRE11 gene mutations [1422C-->A, T481K; 1714C-->T, R571X]. The 1422C-->A allele was inherited from the mother, whereas the 1714C-->T, allele paternally inherited, was apparently null as a result of nonsense-mediated mRNA decay (NMD). Interestingly, the 1714C-->T mutation is the same as previously identified in an unrelated English ATLD family (probands ATLD3 and ATLD4), suggesting an important role for NMD in saving potentially lethal mutations. Lymphoblastoid cell lines (LCLs) derived from ATLD5 and ATLD6 were normal for ATM, but defective for Mre11, Rad50 and Nbs1 (the MRN complex) protein expression. Their response to gamma-radiation was abnormal, as evidenced by the enhanced radiosensitivity, attenuated autophosphorylation of ATM-S1981 and phosphorylation of the ATM targets p53-S15 and Smc1-S966, failure to form Mre11 nuclear foci and defective G1 checkpoint arrest. The fibroblasts, but not LCLs, from ATLD5 and ATLD6 showed an impaired ATM-dependent Chk2 phosphorylation. These findings further underscore the interconnection between ATM activity and MRN function, which rationalizes the clinical similarity between ataxia-telangiectasia (A-T) and ATLD. 相似文献
56.
Tardito D Mori S Racagni G Smeraldi E Zanardi R Perez J 《Journal of affective disorders》2003,76(1-3):249-253
BACKGROUND: Abnormal levels of protein kinase A (PKA) were found in patients with bipolar disorder (BD). Since altered levels are generally accompanied by functional modifications, the purpose of this study was to investigate PKA activity in patients with BD. METHODS: PKA activity was assessed in platelets from 20 drug-free bipolar patients and 19 controls. RESULTS: The cAMP-stimulated PKA activity was significantly increased in bipolar patients compared with controls. LIMITATIONS: This study made use of platelets, which may not fully represent changes occurring in specific brain regions. CONCLUSION: This study adds to the growing evidence suggesting that abnormalities of PKA are associated with BD. 相似文献
57.
58.
Bruno Dallapiccola Giuliana Alimena Viviana Brinchi Giancarlo Isacchi Enrico Gandini 《Cancer Genetics and Cytogenetics》1980,2(4):349-360
Chromosome investigations were carried out in 7 patients with Fanconi's anemia, type Estren-Dameshek. The frequency and types of chromosome instability found in cultured lymphocytes were in accord with those detected in individuals with classical Fanconi's anemia. The break-point distribution indicates a significant excess of breaks in chromosomes No. 1, 2, and 7 and a deficit in No. 18 and X and Y chromosomes. There was a clear clustering of breaks at certain locations in chromosomes No. 1, 2, 3, 7, 9, and 14. The location of the breaks with respect to the bands demonstrated an almost exclusive involvement of the lighter bands, regardless of the banding method used. These results suggest that most breaks take place in the interbands between the G and R bands. In all patients, chromosome instability was less frequent in direct bone marrow preparations than in lymphocyte cultures. However, cultured bone marrow cells showed a significant increase of chromosome aberrations. On the whole, the chromosome data derived from this series of patients are in agreement with those obtained in individuals with classical Fanconi's anemia and give no support to the idea of cytogenetic heterogeneity between subjects affected by these two forms of childhood aplastic anemia. 相似文献
59.
Enrico M Trecarichi Mario Tumbarello de Gaetano Katleen Donati Enrica Tamburrini Roberto Cauda Christina Brahe Francesco D Tiziano 《AIDS research and therapy》2006,3(1):22-4
Despite multiple sexual exposure to HIV-1 virus, some individuals remain HIV-1 seronegative (exposed seronegative, ESN). The
mechanisms underlying this resistance remain still unclear, although a multifactorial pathogenesis can be hypothesised. Although
several genetic factors have been related to HIV-1 resistance, the homozigosity for a mutation in CCR5 gene (the 32 bp deletion, i.e. CCR5-Delta32 allele) is presently considered the most relevant one. In the present study we
analysed the genotype at CCR5 locus of 30 Italian ESN individuals (case group) who referred multiple unprotected heterosexual intercourse with HIV-1 seropositive
partner(s), for at least two years. One hundred and twenty HIV-1 infected patients and 120 individuals representative of the
general population were included as control groups. Twenty percent of ESN individuals had heterozygous CCR5-Delta 32 genotype,
compared to 7.5% of HIV-1 seropositive and 10% of individuals from the general population, respectively. None of the analysed
individuals had CCR5-Delta 32 homozygous genotype. Sequence analysis of the entire open reading frame of CCR5 was performed in all ESN subjects and no polymorphisms or mutations were identified. Moreover, we determined the distribution
of C77G variant in CD45 gene, which has been previously related to HIV-1 infection susceptibility. The frequency of the C77G
variant showed no significant difference between ESN subjects and the two control groups. 相似文献
60.
Coiera E 《International journal of medical informatics》2003,69(2-3):205-222
OBJECTIVE: This paper presents a framework for the design of interactions between human and computational agents working in organisations, mediation by technological systems. DESIGN: The design of interactions within an organisation is viewed from the point of view, not of the technology mediating the new interaction, but of the human and computational agents who interact with each other. RESULTS: Understanding the limits to individual agent resources permits an analysis of the impact that a new interaction will have in a given setting. When we look beyond simple interaction settings, we can use the notion of interaction equilibria to predict the impact of new information and communication technologies within an organisation. Economic supply and demand curves, for example, may allow us to make both qualitative and quantitative predictions about technological adoption of communication systems. CONCLUSION: Rather than focusing solely on characteristics of individual technologies, or psychological and social issues, these can be combined to explain the overall decisions that individuals make when using technologies. Without necessarily understanding all the local decision criteria used by any individual, we can make robust predictions about how a group as a whole will interact. 相似文献