全文获取类型
收费全文 | 1438篇 |
免费 | 56篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 56篇 |
妇产科学 | 28篇 |
基础医学 | 164篇 |
口腔科学 | 28篇 |
临床医学 | 127篇 |
内科学 | 194篇 |
皮肤病学 | 149篇 |
神经病学 | 94篇 |
特种医学 | 45篇 |
外科学 | 233篇 |
综合类 | 4篇 |
预防医学 | 127篇 |
眼科学 | 7篇 |
药学 | 167篇 |
肿瘤学 | 60篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 24篇 |
2019年 | 27篇 |
2018年 | 26篇 |
2017年 | 23篇 |
2016年 | 23篇 |
2015年 | 18篇 |
2014年 | 26篇 |
2013年 | 74篇 |
2012年 | 69篇 |
2011年 | 99篇 |
2010年 | 40篇 |
2009年 | 59篇 |
2008年 | 61篇 |
2007年 | 89篇 |
2006年 | 88篇 |
2005年 | 100篇 |
2004年 | 82篇 |
2003年 | 75篇 |
2002年 | 68篇 |
2001年 | 36篇 |
2000年 | 47篇 |
1999年 | 33篇 |
1998年 | 18篇 |
1997年 | 22篇 |
1996年 | 7篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 8篇 |
1992年 | 19篇 |
1991年 | 15篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 15篇 |
1984年 | 16篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1971年 | 5篇 |
1968年 | 3篇 |
排序方式: 共有1496条查询结果,搜索用时 15 毫秒
51.
52.
53.
Protocol for digital intervention for effective health promotion of small children—A cluster randomized trial 下载免费PDF全文
54.
Nicole A. Najor Lauren Albrecht Natalia Malchin Tomer Goldsmith Meital Grafi‐Cohen Dan Vodo Gilad Fainberg Benjamin Meilik Ilan Goldberg Emily Warshauer Tova Rogers Sarah Edie Akemi Ishida‐Yamamoto Lisa Burzenski Noam Erez Steve A. Murray Alan D. Irvine Lenny Shultz Kathleen J. Green Jouni Uitto Eli Sprecher Ofer Sarig 《Experimental dermatology》2017,26(5):423-430
SVEP1 is a recently identified multidomain cell adhesion protein, homologous to the mouse polydom protein, which has been shown to mediate cell‐cell adhesion in an integrin‐dependent manner in osteogenic cells. In this study, we characterized SVEP1 function in the epidermis. SVEP1 was found by qRT‐PCR to be ubiquitously expressed in human tissues, including the skin. Confocal microscopy revealed that SVEP1 is normally mostly expressed in the cytoplasm of basal and suprabasal epidermal cells. Downregulation of SVEP1 expression in primary keratinocytes resulted in decreased expression of major epidermal differentiation markers. Similarly, SVEP1 downregulation was associated with disturbed differentiation and marked epidermal acanthosis in three‐dimensional skin equivalents. In contrast, the dispase assay failed to demonstrate significant differences in adhesion between keratinocytes expressing normal vs low levels of SVEP1. Homozygous Svep1 knockout mice were embryonic lethal. Thus, to assess the importance of SVEP1 for normal skin homoeostasis in vivo, we downregulated SVEP1 in zebrafish embryos with a Svep1‐specific splice morpholino. Scanning electron microscopy revealed a rugged epidermis with perturbed microridge formation in the centre of the keratinocytes of morphant larvae. Transmission electron microscopy analysis demonstrated abnormal epidermal cell‐cell adhesion with disadhesion between cells in Svep1‐deficient morphant larvae compared to controls. In summary, our results indicate that SVEP1 plays a critical role during epidermal differentiation. 相似文献
55.
Medical and Surgical Dermatology - 相似文献
56.
Jouni Sirvi Hannele Lahtinen Paavo Riekkinen Jr. Paavo J. Riekkinen 《Experimental neurology》1994,125(2)
The present experiment studied whether a dysfunction of the noradrenergic neurons is related to spatial learning impairment by investigating the levels of noradrenaline in the brain and periphery as well as the acquisition of water maze task in saline-pretreated young rats, in noradrenergic neurotoxin (DSP-4)-pretreated young rats and in saline-pretreated aged rats. Aged rats, which had an increased escape latency onto the hidden platform, revealed a decreased noradrenaline content in the heart, but not in the hippocampus, striatum, or hypothalamus, whereas DSP-4-pretreated rats had decreased noradrenaline content in the brain; the acquisition of water maze task was not impaired. These results suggest that the peripheral noradrenergic system can show age-related changes different from those in the central noradrenergic system, and they failed to provide support for the hypothesis that decreased activity of the central noradrenergic nerves is related to impairment in the acquisition of the water maze task. 相似文献
57.
Jaakkola JJ Jaakkola N Piipari R Jaakkola MS 《The Journal of allergy and clinical immunology》2002,109(5):784-788
BACKGROUND: Studies of exposure to pets and the risk of asthma have provided conflicting results. OBJECTIVE: We conducted a population-based incident case-control study to assess the relationship of current and previous pet keeping with the risk of adult-onset asthma. We also investigated whether genetic propensity as a result of parental atopy modifies these relations. METHODS: From the source population of 441,000 inhabitants of a geographically defined area in South Finland, we systematically recruited, during a 2.5-year period, all new cases of asthma in 21- to 63-year-old adults and randomly selected control subjects. The clinically diagnosed case series consisted of 521 adults with newly diagnosed asthma and a control series of 932 control subjects. Information on current and past exposure to hairy pets was collected by using a self-administered questionnaire. RESULTS: In logistic regression analysis the risk of asthma was lower among subjects with pets during the past 12 months (adjusted odds ratio [OR], 0.74; 95% confidence interval [CI], 0.57-0.96) but higher among subjects with pets more than 12 months previously (adjusted OR, 1.39; 95% CI, 1.05-1.84). Parental atopy increased the risk of asthma (OR, 1.88; 95% CI, 1.47-2.41), but there was no interaction between parental atopy and pet exposure. CONCLUSIONS: The present results are consistent with the hypothesis that both keeping furry pets and parental atopy increase the risk of asthma development in adulthood. Parental atopy does not modify the effects of pet exposure. The negative association between current pets and the risk of asthma is consistent with selective avoidance of these pets by symptomatic individuals. 相似文献
58.
Genetic and phenotypic divergence of Drosophila virilis laboratory strains originating from different parts of the species range were studied with the aid of microsatellite markers
and by analysing male courtship songs. The strains from America, Europe, continental Asia and Japan showed moderate geographic
clustering both at the genetic level and in several traits of the male song. The genetic distances and the song divergence
of the strains did not show significant association, which suggests that the songs have not diverged solely as a side-effect
of genetic divergence. Comparison of the songs of the laboratory strains to those of freshly collected strains showed that
pulse characters of the song are quite sensitive to culture conditions. While laboratory rearing of the flies had no effect
on the number of pulses in a pulse train or the pulse train length, the tendency of the sound pulses to become longer during
laboratory maintenance could explain the lack of geographic variation in pulse length and inter pulse interval. Sensitivity
of songs to culturing conditions should be taken in account in studies on song divergence.
Edited by Young-Kyu Kim. 相似文献
59.
Caveolins as tumour markers in lung cancer detected by combined use of cDNA and tissue microarrays 总被引:5,自引:0,他引:5
Wikman H Seppänen JK Sarhadi VK Kettunen E Salmenkivi K Kuosma E Vainio-Siukola K Nagy B Karjalainen A Sioris T Salo J Hollmén J Knuutila S Anttila S 《The Journal of pathology》2004,203(1):584-593
To identify new potential diagnostic markers for lung cancer, the expression profiles of 37 lung tumours were analysed using cDNA arrays. Seven samples were from small-cell lung cancer (SCLC), two from large-cell neuroendocrine tumours (LCNEC), and 28 from other non-small-cell lung cancers (mainly squamous cell cancer and adenocarcinoma). Principal component analysis and the permutation test were used to detect differences in the gene expression profiles and a set of genes was found that distinguished high-grade neuroendocrine carcinomas (SCLC and LCNEC) from other lung cancers. In addition, several genes, such as caveolin-1 (CAV1) and caveolin-2 (CAV2), were constantly deregulated in all types of tumour sample, compared with normal tissue. The expression of these two genes was investigated further at the protein level on a tissue microarray containing tumours from 161 patients and normal tissues. Immunostaining for CAV1 was negative in 48% of tumours, whereas 28% of the tumours did not express CAV2. Lack of CAV1 protein expression was not caused by methylation or mutation. In stage I adenocarcinomas, CAV2 protein expression correlated with shorter survival. In conclusion, the present study was able to identify genes that have not previously been implicated in lung cancer by the combined use of two different array techniques. Some of these genes may provide novel diagnostic markers for lung cancer. 相似文献
60.
Pharmacokinetics of clonidine were examined in ten women during pregnancy, in nine during nursing, and in the newborns of these women. Clonidine crosses the placenta easily, and its concentrations were equal in maternal serum and umbilical cord serum. Amniotic fluid concentrations were up to four times that found in serum. Clonidine concentrations in milk were roughly twice that in maternal serum; in the serum of the newborns the concentrations were about half those of the mothers. All concentrations corresponded well to the doses of the drug. The neurologic examinations and assessments of serum electrolytes and blood glucose showed results parallel with those of newborns of nontreated mothers. 相似文献