全文获取类型
收费全文 | 3823篇 |
免费 | 278篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 96篇 |
妇产科学 | 52篇 |
基础医学 | 643篇 |
口腔科学 | 35篇 |
临床医学 | 340篇 |
内科学 | 918篇 |
皮肤病学 | 74篇 |
神经病学 | 300篇 |
特种医学 | 111篇 |
外科学 | 673篇 |
综合类 | 21篇 |
一般理论 | 1篇 |
预防医学 | 255篇 |
眼科学 | 24篇 |
药学 | 253篇 |
中国医学 | 6篇 |
肿瘤学 | 248篇 |
出版年
2023年 | 16篇 |
2022年 | 23篇 |
2021年 | 61篇 |
2020年 | 48篇 |
2019年 | 61篇 |
2018年 | 80篇 |
2017年 | 59篇 |
2016年 | 80篇 |
2015年 | 68篇 |
2014年 | 107篇 |
2013年 | 155篇 |
2012年 | 266篇 |
2011年 | 278篇 |
2010年 | 159篇 |
2009年 | 149篇 |
2008年 | 251篇 |
2007年 | 258篇 |
2006年 | 292篇 |
2005年 | 245篇 |
2004年 | 252篇 |
2003年 | 232篇 |
2002年 | 220篇 |
2001年 | 32篇 |
2000年 | 25篇 |
1999年 | 35篇 |
1998年 | 67篇 |
1997年 | 43篇 |
1996年 | 45篇 |
1995年 | 41篇 |
1994年 | 32篇 |
1993年 | 26篇 |
1992年 | 17篇 |
1991年 | 22篇 |
1990年 | 24篇 |
1989年 | 20篇 |
1988年 | 22篇 |
1987年 | 16篇 |
1986年 | 21篇 |
1985年 | 24篇 |
1984年 | 22篇 |
1983年 | 15篇 |
1982年 | 24篇 |
1981年 | 22篇 |
1980年 | 20篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 11篇 |
排序方式: 共有4108条查询结果,搜索用时 15 毫秒
31.
32.
The effects of self-generated expectancy of stimulus content on the visual evoked potential to physically identical stimuli were studied in college students. The subject set up his own internal expectant; by choosing to see either a bright or dim Hash. When a bright or dim Hash was anticipated, the potentials evoked by u medium stimulus intensity resembled the responses elicited by an actual bright or dim flash, respectively. Significant differences in visual evoked potential amplitude were obtained between identical medium intensity stimuli depending on the stimulus intensity expected, despite (he constant physical properties of the stimulus. 1 In1 results suggest that a subject's expectancy of certain physical parameters of a stimulus are as important In determining (he resultant visual evoked potential as the actual physical features of the stimulus. 相似文献
33.
Quantitation of HHV-7 genome by real-time polymerase chain reaction assay using MGB probe technology 总被引:13,自引:0,他引:13
Fernandez C Boutolleau D Manichanh C Mangeney N Agut H Gautheret-Dejean A 《Journal of virological methods》2002,106(1):11-16
A real-time PCR assay was developed to quantify human herpesvirus-7 (HHV-7) genome based on TaqMan technology using the new MGB probe. Primers and probe were chosen in the conserved U100 gene. Plasmid containing the sequence of interest was constructed for the standardisation of the method and to assess its sensitivity. This HHV-7 genomic quantitation assay has a threshold sensitivity of fourteen equivalent genome copy number (EqCop) per reaction. This method was applied to the quantitation of HHV-7 in the peripheral blood mononuclear cells (PBMCs) obtained from 31 healthy subjects. Eighty seven per cent had HHV-7 positive detection in the PBMCs with a viral load ranging from 275 to 14545 EqCop per million of cells. This method presents interesting characteristics with a wide range of quantitation, a good sensitivity, and constitutes a new tool for the study of HHV-7 infection in vivo and in vitro. 相似文献
34.
Molecular Epidemiology of Ampicillin-Resistant Non-β-Lactamase-Producing Haemophilus influenzae
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Louise Gazagne Catherine Delmas Edouard Bingen Henri Dabernat 《Journal of clinical microbiology》1998,36(12):3629-3635
Resistance to ampicillin without β-lactamase production is not a frequent occurrence among Haemophilus influenzae strains. This kind of resistance is encountered in unencapsulated strains isolated from bronchial secretions and ear, nose, and throat specimens and is exceptional in H. influenzae type b. We studied 29 of these strains from various areas in France and 2 reference strains. Strains were compared by using ribotyping, arbitarily primed PCR with two primers, and pulsed-field gel electrophoresis. Each technique enabled the identification of 20 to 23 different patterns among the 31 strains. The combination of the different patterns for the strains obtained by the different techniques provided 27 distinct profiles. According to these results, it seems that the clonal propagation of these resistant strains does not occur. 相似文献
35.
Hypothermic Machine Preservation in Liver Transplantation Revisited: Concepts and Criteria in the New Millennium 总被引:5,自引:0,他引:5
van der Plaats A 't Hart NA Verkerke GJ Leuvenink HG Ploeg RJ Rakhorst G 《Annals of biomedical engineering》2004,32(4):623-631
To overcome the present shortage of liver donors by expansion of the existing donor pool and possibly lengthening of the storage time, hypothermic machine perfusion of the liver as a dynamic preservation method is revisited. The three most important aspects are defined to be the type of preservation solution, the characteristics of perfusion dynamics, and the oxygen supply. Reviewing hypothermic liver machine perfusion experiments, the University of Wisconsin machine preservation solution is the solution most used. It is also found that nothing conclusive can be said about the optimal perfusion characteristics, since either perfusion pressure or perfusion flow is reported. The best estimation is perfusion of the liver in a physiological manner, i.e. pulsatile arterial perfusion and continuous portal venous perfusion. The applied pressures could be chosen to be somewhat lower than physiological pressures to prevent possible endothelial cell damage. Oxygen supply is necessary to achieve optimal preservation of the liver. The minimal amount of partial oxygen pressure required is inversely related to the normalized flow. Incorporating these features in a system based on existing standard surgical and organ sharing procedures and which is able to work stand-alone for 24 h, weighing less than 23 kg, could successfully implement this technique into every day clinical practise. 相似文献
36.
Franck Halary Marie-Alix Peyrat Eric Champagne Miguel Lopez-Botet Alessandro Moretta Lorenzo Moretta Henri Vi Jean-Jacques Fourni Marc Bonneville 《European journal of immunology》1997,27(11):2812-2821
The majority of peripheral blood γδ T cells in human adults expresses T cell receptors (TCR) with identical V regions (Vγ9 and Vδ2). These Vγ9Vδ2 T cells recognize the major histocompatibility complex (MHC) class I-deficient B cell line Daudi and broadly distributed nonpeptidic antigens present in bacteria and parasites. Here we show that unlike αβ or Vγ9? γδ T cells, the majority of Vγ9Vδ2T cells harbor natural killer inhibitory receptors (KIR) (mainly CD94/NKG2A heterodimers), which are known to deliver inhibitory signals upon interaction with MHC class I molecules. Within Vγ9δ2 T cells, KIR were mainly expressed by clones exhibiting a strong lytic activity against Daudi cells. In stark contrast, almost all Vγ9Vδ2 T cell clones devoid of killing activity were KIR?, thus suggesting a coordinate acquisition of KIR and cytotoxic activity within Vγ9Vδ2 T cells. In functional terms, KIR inhibited lysis of MHC class I-positive tumor B cell lines by Vγ9Vδ2 cytotoxic T lymphocytes (CTL) and raised their threshold of activation by microbial antigens presented by MHC class I-positive cells. Furthermore, masking KIR or MHC class I molecules revealed a TCR-dependent recognition by Vγ9Vδ2 CTL of ligands expressed by activated T lymphocytes, including the effector cells themselves. Taken together, these results suggest a general implication of Vγ9Vδ2 T cells in immune response regulation and a central role of KIR in the control of self-reactive γδ CTL. 相似文献
37.
Astrid LA. Kuijpers Rolph Pfundt Patrick LJM Zeeuwen Henri OF. Molhuizen Edwin CM. Mariman Peter CM. van de Kerkhof Joost Schalkwijk 《Clinical genetics》1998,54(1):96-101
Psoriasis is a multifactorial skin disease characterised by epidermal abnormalities and infiltration by lymphocytes and polymorphonuclear leukocytes (PMN). Skin-derived antileukoproteinase (SKALP), also known as elafin, is a potent inhibitor of human leukocyte elastase and proteinase 3, two PMN-derived proteinases implicated in tissue destruction and leukocyte migration. We have shown that, at least at the protein level, SKALP is significantly decreased in lesional skin of patients with pustular psoriasis compared with plaque-type psoriasis. This finding raised the possibility that SKALP could be one of the candidate genes for pustular forms of psoriasis. We therefore performed single strand conformation polymorphism (SSCP) analysis on the SKALP gene to screen for mutations/polymorphisms in the exons of 30 patients with plaque-type psoriasis, 15 patients with pustular psoriasis and 48 healthy controls. In exon 1 a polymorphism was detected at position + 43 relative to the translation start site, resulting in a substitution of threonine for alanine in the signal peptide. In the promoter region a dinucleotide repeat polymorphism was identified. Both polymorphisms were not associated with pustular psoriasis, or psoriasis in general. Our data indicate that the decrease in SKALP activity in pustular psoriasis is not caused by mutations in the coding region of the gene, and that there is no allelic association between pustular psoriasis and SKALP gene polymorphisms. 相似文献
38.
Gastrointestinal stromal tumors (GISTs)--the Lebanese experience 总被引:1,自引:0,他引:1
Salamoun W El Hajj G Aftimos G Moukharbel N Khairallah S Bejjani N Abou Sleiman CH Abou Atmeh J Azar H Elias E Abi Gerges D 《Molecular immunology》2003,39(17-18):1129-1132
39.
40.
Follicle stimulating hormone measured in unextracted urine throughout the menstrual cycle correlates with age and ovarian reserve 总被引:3,自引:0,他引:3
Oosterhuis GJ Vermes I Michgelsen HW Schoemaker J Lambalk CB 《Human reproduction (Oxford, England)》2002,17(3):641-646
BACKGROUND: A method was previously described to measure FSH reliably in unextracted urine. The aim of the current study was to establish the course of FSH measured in urine throughout the cycle. METHOD: Daily urinary FSH (uFSH) concentrations were determined in 14 regularly menstruating volunteers aged 23-39 years during one complete menstrual cycle. RESULTS: In each subject, mean daily uFSH measured in urine, as gold standard for FSH tone, correlated significantly with FSH in early follicular phase fixed to menstruation on cycle day 3 (r = 0.75, P = 0.002), or fixed to ovulation 9 days before the pre-ovulatory FSH surge (r = 0.87, P = 0.0001), or when selected as being the highest follicular phase value (r = 0.91, P = 0.0001). Age correlated significantly with mean daily uFSH (r = 0.67, P = 0.009), highest follicular phase uFSH (r = 0.60, P = 0.024), uFSH on cycle day 3 (r = 0.80, P = 0.0006), and uFSH 9 days before FSH surge (r = 0.65, P = 0.0016). The uFSH was also measured on cycle day 3 in 104 IVF patients in a cycle prior to pituitary down-regulation. The uFSH correlated significantly with numbers of follicles (P = 0.02) and oocytes (P = 0.024). CONCLUSION: It is concluded that cycle day 3 uFSH is a good reflection of the mean uFSH of the complete cycle, and there is a highly significant correlation between uFSH and age and ovarian reserve. Measurement of FSH in urine on cycle day 3 seems to be a reliable and non-invasive tool for determining ovarian reserve in IVF. 相似文献