全文获取类型
收费全文 | 7219篇 |
免费 | 445篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 289篇 |
妇产科学 | 265篇 |
基础医学 | 821篇 |
口腔科学 | 69篇 |
临床医学 | 1359篇 |
内科学 | 1208篇 |
皮肤病学 | 112篇 |
神经病学 | 539篇 |
特种医学 | 133篇 |
外科学 | 635篇 |
综合类 | 76篇 |
一般理论 | 10篇 |
预防医学 | 1130篇 |
眼科学 | 157篇 |
药学 | 358篇 |
1篇 | |
中国医学 | 6篇 |
肿瘤学 | 458篇 |
出版年
2023年 | 46篇 |
2022年 | 70篇 |
2021年 | 138篇 |
2020年 | 79篇 |
2019年 | 152篇 |
2018年 | 158篇 |
2017年 | 146篇 |
2016年 | 150篇 |
2015年 | 144篇 |
2014年 | 223篇 |
2013年 | 359篇 |
2012年 | 507篇 |
2011年 | 561篇 |
2010年 | 292篇 |
2009年 | 250篇 |
2008年 | 512篇 |
2007年 | 520篇 |
2006年 | 506篇 |
2005年 | 476篇 |
2004年 | 453篇 |
2003年 | 434篇 |
2002年 | 430篇 |
2001年 | 65篇 |
2000年 | 63篇 |
1999年 | 64篇 |
1998年 | 72篇 |
1997年 | 82篇 |
1996年 | 72篇 |
1995年 | 55篇 |
1994年 | 44篇 |
1993年 | 52篇 |
1992年 | 36篇 |
1991年 | 18篇 |
1990年 | 31篇 |
1989年 | 34篇 |
1988年 | 31篇 |
1987年 | 20篇 |
1986年 | 17篇 |
1985年 | 26篇 |
1984年 | 27篇 |
1983年 | 22篇 |
1982年 | 29篇 |
1981年 | 19篇 |
1980年 | 25篇 |
1979年 | 17篇 |
1978年 | 22篇 |
1977年 | 16篇 |
1976年 | 12篇 |
1975年 | 17篇 |
1974年 | 9篇 |
排序方式: 共有7676条查询结果,搜索用时 15 毫秒
21.
Justin C Wise Rose A Sevcik Robin D Morris Maureen W Lovett Maryanne Wolf 《J. Speech Lang. Hear. Res.》2007,50(4):1093-1109
PURPOSE: Some researchers (F. R. Vellutino, F. M. Scanlon, & M. S. Tanzman, 1994) have argued that the different domains comprising language (e.g., phonology, semantics, and grammar) may influence reading development in a differential manner and at different developmental periods. The purpose of this study was to examine proposed causal relationships among different linguistic subsystems and different measures of reading achievement in a group of children with reading disabilities. METHODS: Participants were 279 students in 2nd to 3rd grade who met research criteria for reading disability. Of those students, 108 were girls and 171 were boys. In terms of heritage, 135 were African and 144 were Caucasian. Measures assessing pre-reading skills, word identification, reading comprehension, and general oral language skills were administered. RESULTS: Structural equation modeling analyses indicated receptive and expressive vocabulary knowledge was independently related to pre-reading skills. Additionally, expressive vocabulary knowledge and listening comprehension skills were found to be independently related to word identification abilities. CONCLUSION: Results are consistent with previous research indicating that oral language skills are related to reading achievement (e.g., A. Olofsson & J. Niedersoe, 1999; H. S. Scarborough, 1990). Results from this study suggest that receptive and expressive vocabulary knowledge influence pre-reading skills in differential ways. Further, results suggest that expressive vocabulary knowledge and listening comprehension skills facilitate word identification skills. 相似文献
22.
Maureen Mayhew 《Canadian Medical Association journal》2002,167(12):1371-1373
23.
The incidence of primary cutaneous malignant melanoma is increasing in the developed countries. Cutaneous malignant melanomas diagnosed in our Department over a period of fifty years from 1930 to 1980 were examined to see if there was any change in their histological features. In 1930 and 1955, over 90% of malignant melanomas presented as tumours infiltrating deep into the subepithelial tissue. By 1980, 55% of tumours presented with deeply infiltrating lesions and only 20% occurred at a stage where adequate local excision could provide hope of a cure. There is thus a need for greater awareness among the medical profession and the public if we hope to be able to treat malignant melanomas at an early stage. 相似文献
24.
Goddijn Mariette; Joosten Hannie; Knegt Lia; van der Veen Fulco; Franssen Maureen; Bonsel Gouke; Leschot Nico 《Human reproduction (Oxford, England)》2004,19(9):2172
Sir, We thank Mayumi Sugiura-Ogasawara et al. for their commentson our paper (Goddijn et al., 2004 相似文献
25.
Development and Evaluation of a Tetraplex Flow Cytometric Assay for Quantitation of Serum Antibodies to Neisseria meningitidis Serogroups A, C, Y, and W-135 下载免费PDF全文
Gouri Lal Paul Balmer Helen Joseph Maureen Dawson Ray Borrow 《Clinical and Vaccine Immunology : CVI》2004,11(2):272-279
A rapid and simple method for the simultaneous quantitation of serum immunoglobulin G (IgG) antibodies specific for Neisseria meningitidis serogroups A, C, Y, and W-135 was developed and evaluated. Four bead sets were generated, each conjugated with one of the meningococcal capsular polysaccharides (A, C, Y, or W-135) and serologically assessed by the use of antimeningococcal international reference sera. Cross-reactivity studies demonstrated no inhibition between monoplex and multiplex assays, and the assay was linear over a 24-fold serum dilution range. Inhibition studies demonstrated that the assay is specific, with <25% heterologous inhibition occurring. The assay was also found to have low intra- and interassay variations and limits of detection ≤650 pg/ml. A comparison of the meningococcal bead assay with the standardized meningococcal enzyme-linked immunosorbent assay showed a good correlation between the IgG concentrations obtained by each assay. The tetraplex assay has the potential to be an important addition to the serologic evaluation of meningococcal capsular polysaccharide conjugate vaccines. 相似文献
26.
Tangir J Bonafé N Gilmore-Hebert M Henegariu O Chambers SK 《Clinical & experimental metastasis》2004,21(6):477-483
The aggressive behavior of breast cancer cells can at times be modulated by hormonal mechanisms. Exposure to glucocorticoids
(GC) has been shown to stimulate the invasiveness, motility and adhesiveness of breast cancer cells containing the glucocorticoid
receptor. This is largely explained by GC-associated overexpression of the c-fms proto-oncogene, which encodes the receptor for the colony stimulating factor-1 (CSF-1). Our objective is to investigate additional
GC-associated genetic alterations that could modulate c-fms related malignant behavior in breast cancer cells. A microarray technique using an oligonucleotide array representing 16,700
known expressed human genes was used to analyze the gene expression profile of breast cancer cells exposed to dexamethasone
(Dex) or vehicle. Results were confirmed by western blot analysis. Six genes were found to be consistently differentially
overexpressed in the Dex-exposed cells compared to control. We focused on serum-glucose kinase 1 (SGK1), a serine-threonine
kinase known to be involved in intracellular signal transduction pathways and induced by GC and serum. An adhesion assay was
performed on extracellular matrix after exposing the breast cancer cells to Dex, CSF-1 or to Dex or CSF-1 plus LY294002, a
functional inhibitor of SGK1 action. Exposure to LY294002 significantly decreased both CSF-1 and Dex-induced adhesiveness
to the level of control cells. SGK1 may act as a downstream intracellular regulator of c-fms, particularly of c-fms-induced adhesiveness of breast cancer cells after exposure to GC or CSF-1. This finding may have implications for potential
therapeutic interventions aimed at decreasing the aggressiveness of breast cancer cells.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
27.
Proton nuclear magnetic resonance was used to follow glucose metabolism in Giardia lamblia. Under strictly anaerobic conditions this organism produces equimolar ethanol and alanine as well as CO2 and some acetate. Aerobically the production of both alanine and ethanol are inhibited and more acetate and CO2 are formed. These changes in the balance of products are reversible over the range 0-46 microM O2. In the presence of 46 microM O2, alanine was not detectable. The O2-sensitivity of alanine production may highlight the necessity for redox-balancing reactions in an organism exposed in situ to fluctuating concentrations of O2. 相似文献
28.
Cornel AJ McAbee RD Rasgon J Stanich MA Scott TW Coetzee M 《Journal of medical entomology》2003,40(1):36-51
Comparisons of five morphological characters, 12 enzyme electrophoresis profiles, and Wolbachia pipientis infection rates were used to characterize populations of members of the Culex pipiens L. complex in California and South Africa. In South Africa, male phallosome DV/D ratio, male maxillary palp index, branching of siphonal seta 1a, the enzyme locus Mdhp-1, and W. pipientis infection rates proved highly diagnostic for separating Culex quinquefasciatus from Cx. pipiens phenotypes. In Johannesburg, where sympatric members of the Cx. pipiens complex were analyzed as one population, a significant Wahlund Effect was observed in the enzyme loci such as Ao, 6-Pgdh, Mdh-2, and Pgm. In California, all populations of the Cx. pipiens complex were in Hardy Weinberg equilibrium at all polymorphic enzyme loci examined. Additionally, in California, all populations had similar W. pipientis infection rates and appeared morphologically identical (except for DV/D ratio, in extreme north and south). These findings indicate that in South Africa, Cx. pipiens and Cx. quinquefasciatus remain as genetically distinct populations and behave as separate species. Conversely, in California, there is considerable genetic introgression between Cx. pipiens and Cx. quinquefasciatus, and they behave as a single species. 相似文献
29.
The case of a retarded child with trisomy of the short arm of chromosome 8 associated with translocation between the short arm of chromosome 8 and the long arm of chromosome 22 is reported. Balanced translocation involving the same chromosomes was present in the mother and brother of the propositus. The specific chromosomes involved in the abnormality in this family were identified by use of fluorescence microscopy with quinacrine mustard staining, autoradiography and Giemsa banding. This appears to be the first case report of this anomaly, although trisomy of the short arm of chromosome 9 has been reported previously. 相似文献
30.