全文获取类型
收费全文 | 3388篇 |
免费 | 401篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 136篇 |
妇产科学 | 64篇 |
基础医学 | 456篇 |
口腔科学 | 109篇 |
临床医学 | 451篇 |
内科学 | 650篇 |
皮肤病学 | 53篇 |
神经病学 | 291篇 |
特种医学 | 204篇 |
外科学 | 354篇 |
综合类 | 143篇 |
一般理论 | 1篇 |
预防医学 | 339篇 |
眼科学 | 77篇 |
药学 | 245篇 |
中国医学 | 4篇 |
肿瘤学 | 210篇 |
出版年
2022年 | 39篇 |
2021年 | 104篇 |
2020年 | 59篇 |
2019年 | 77篇 |
2018年 | 96篇 |
2017年 | 64篇 |
2016年 | 60篇 |
2015年 | 56篇 |
2014年 | 79篇 |
2013年 | 122篇 |
2012年 | 162篇 |
2011年 | 125篇 |
2010年 | 96篇 |
2009年 | 81篇 |
2008年 | 137篇 |
2007年 | 158篇 |
2006年 | 116篇 |
2005年 | 132篇 |
2004年 | 111篇 |
2003年 | 111篇 |
2002年 | 105篇 |
2001年 | 94篇 |
2000年 | 99篇 |
1999年 | 94篇 |
1998年 | 47篇 |
1997年 | 41篇 |
1996年 | 52篇 |
1995年 | 48篇 |
1994年 | 43篇 |
1993年 | 49篇 |
1992年 | 62篇 |
1991年 | 65篇 |
1990年 | 75篇 |
1989年 | 71篇 |
1988年 | 78篇 |
1987年 | 58篇 |
1986年 | 59篇 |
1985年 | 46篇 |
1984年 | 49篇 |
1983年 | 40篇 |
1980年 | 31篇 |
1979年 | 38篇 |
1978年 | 28篇 |
1977年 | 25篇 |
1976年 | 26篇 |
1971年 | 37篇 |
1970年 | 29篇 |
1969年 | 31篇 |
1967年 | 28篇 |
1966年 | 31篇 |
排序方式: 共有3812条查询结果,搜索用时 15 毫秒
991.
992.
Expression of Tip60, an androgen receptor coactivator,and its role in prostate cancer development 总被引:9,自引:0,他引:9
Halkidou K Gnanapragasam VJ Mehta PB Logan IR Brady ME Cook S Leung HY Neal DE Robson CN 《Oncogene》2003,22(16):2466-2477
Prostate cancer (CaP) is initially androgen sensitive and responsive to hormone ablation therapy. However, cancer growth recurs despite androgen deprivation in the majority of cases of advanced disease. The molecular basis of this progression still remains unknown. The significance of androgen receptor (AR) coactivator proteins in this androgen-dependent malignancy is only beginning to emerge. In the present study, we examined the role of Tat interactive protein, 60 kDa (Tip60), an AR coactivator, in CaP progression. In hormone refractory CaP biopsies, we observed a nuclear accumulation of Tip60 expression in contrast to a more diffuse distribution pattern observed in benign prostate hyperplasia and primary CaP. Furthermore, in both the prostate xenograft model CWR22 and the LNCaP CaP cell line, we observed that androgen withdrawal promoted upregulation of Tip60 as well as nuclear accumulation. In contrast, androgen exposure resulted in decreased Tip60 expression that was more closely linked to a cytoplasmic presence. Chromatin immunoprecipitation analysis revealed Tip60's recruitment to the PSA gene promoter in both androgen-dependent and -independent cell lines. Thus, in vitro and in vivo data support a possible role for Tip60 in the molecular pathway leading to the development of androgen-independent CaP following long-term androgen deprivation therapy. 相似文献
993.
994.
PURPOSE: We examined the ability of sextant prostate biopsies in combination with other preoperative data to predict side and sextant site of prostate cancer extracapsular extension in a large cohort of patients. MATERIALS AND METHODS: We examined 223 contemporary cases of prostate cancer managed by radical prostatectomy. Using logistic regression analysis, we determined whether patient age, Gleason score, clinical stage, prostate specific antigen, number of positive sextants, biopsy location or percent of biopsy cores positive for cancer in a sextant site, side and overall gland was predictive of location of pathological extracapsular extension into periprostatic tissue. RESULTS: Of 41 of the 223 (18%) patients with nonorgan confined disease extracapsular extension was localized to 45 sextant sites in 36 (apex 8, mid 22, base 15) while only side of extension was known in 5. In a multivariate analysis the best predictors of the risk of extracapsular extension on a side were average percent biopsy cores positive for cancer overall 15 or greater (odds ratio 8.4, p <0.0001) and average from 3 ipsilateral biopsies 15 or greater (odds ratio 7.4, p <0.0001). When used in combination these 2 factors yielded a model with a positive predictive value of 37% and a negative predictive value of 95%. Sextant specific percent biopsy cores positive for cancer was predictive of risk of extracapsular extension in a sextant (odds ratio 2.5, p = 0.020). CONCLUSIONS: Our data demonstrate that average overall and per side percent biopsy cores positive for cancer is a significant predictor of risk of extracapsular extension on a side. Sextant specific percent biopsy cores positive for cancer is predictive of sextant site of extension. The high negative predictive value of the side specific model identifies patients who are good candidates for nerve sparing surgery. 相似文献
995.
BACKGROUND: The successful clinical application of pig-to-primate xenotransplantation is currently limited by the development of an acute vascular rejection, which is thought to involve an induced humoral immune response to the galactose alpha1,3 galactose (alpha-Gal) antigen. Successful xenotransplantation may require the development of novel methods for removal or neutralization of anti-Gal antibodies and anti-Gal-producing B cells. The large diversity of the B-cell repertoire makes it difficult, however, to isolate and study anti-Gal B-cell development. METHODS: We have established a transgenic mouse model for investigating anti-Gal B cells by introducing a transgene encoding both heavy and light chains for an anti-Gal IgM antibody into an alpha-galactosyltransferase-deficient (Gal-/-) background. We have characterized the frequency, phenotype, and function of transgenic anti-Gal B cells by multiparameter flow cytometric analysis and ELISA. RESULTS: ELISA analysis of serum from animals with the transgene in an alpha-galactosyltransferase-deficient background (Tg Gal-/-), from transgenic animals with a heterozygous alpha-galactosyltransferase background (Tg Gal-/+), and from nontransgenic alpha-galactosyltransferase-deficient littermates (Gal-/-) demonstrated elevated expression of anti-Gal antibodies in Tg Gal-/- mice compared with nontransgenic Gal-/- animals and a lack of transgene expression in the Tg Gal-/+ mice. Anti-Gal antibody expression in Tg Gal-/- mice could be increased by immunization with an ovalbumin-Gal glycoconjugate in vivo and through stimulation with lipopolysaccharide in vitro. Multiparameter flow cytometric analysis indicates that 50% to 80% of splenic and peritoneal B cells expressed the transgene and excluded endogenous immunoglobulin gene rearrangements. The majority of these B cells expressed anti-Gal receptors on the surface, as identified by staining with a fluorescein isothiocyanate-bovine serum albumin-Gal glycoconjugate. FACS analysis of the Tg Gal-/- B cells identified them as a population of CD21highCD23lowIgMhigh marginal zone B cells in the spleen and CD5-CD23low B1 cells in the peritoneal cavity. CONCLUSIONS: These observations suggest that this model can be used to study the regulation of anti-Gal B cells and can establish a reliable source of functional anti-Gal B cells, which could be used to test the effectiveness of alpha-Gal-specific immunosuppressive reagents. 相似文献
996.
997.
998.
A multitude of responsibilities, environmental and social influences, and stressors place farm women at high risk for depressive symptoms. This cross sectional survey design study examines demographic, health status, and farm lifestyle characteristics, behaviors and beliefs as risk factors contributing to depressive symptoms among farm women in southeast Louisiana. The study was conducted in a stratified, random sample of 657 women 18 years and older. Factors predictive of depressive symptoms in adjusted logistic regression included those who experience poor health, perceive hazards associated with farming, experience recent farm-related injuries and engage in farming over longer periods of time. These findings help target interventions toward women at risk for depressive symptoms. 相似文献
999.
McConachie HR Salt A Chadury Y McLachlan A Logan S 《Child: care, health and development》1999,25(2):157-168
The area of child disability is the 'Cinderella' of community child health services. It lacks a clear commissioning model, agreed quality standards or guidance on the level of resources required. In this climate of uncertainty, a national survey of Child Development Teams was undertaken in order to describe their basic structure and processes. The paper reports information from 242 multidisciplinary teams providing local services, with statutory funding, to children with neurodevelopmental disability and their families. The picture presented is encouraging in part. For example, 79% of teams operate from a Child Development Centre, which may be expected to enhance team communication. In terms of the initial assessment process for a developmentally delayed child, most teams (91%) report that they would hold a case discussion afterwards, although only 74% would always include parents, and only 70% always give their report(s) to parents. The impression of management practices is weak, with only 62% giving a clear answer about who manages the team, and less than half having a written policy or contract for the team's work. The survey findings provide a sampling framework from which further evaluative research can be generated. 相似文献
1000.
Cutaneous uptake of 14C-HD vapor by the hairless guinea pig 总被引:2,自引:0,他引:2
Logan TP Millard CB Shutz M Schulz SM Lee RB Bongiovanni R 《Drug and chemical toxicology》1999,22(2):375-387
The hairless guinea pig (HGP) is used by our laboratory to model the human cutaneous response to sulfur mustard (HD), bis(2-chloroethylsulfide), exposure. We determined the HD content in the skin of HGP after a 7-min exposure to vapors saturated with a mixture of HD and 14C-HD. Concentration/time (CT) values in the range of 2 micrograms/cm2/min were determined by counting skin 14C disintegrations per min (dpm) in animals euthanized immediately after exposure. These values are similar to human penetration rates obtained by other investigators. A rate curve monitoring the reduction in skin 14C dpm was developed for animals euthanized between 0 and 24 hr post- exposure. This curve showed the greatest change after 1 hr. The epidermal (62%) to dermal (38%) ratio of 14C at 24 hr was measured for two animals. We saw no site preference for HD penetration among the 8 sites used. The 14C content of template adhesive tape was determined to follow HD distribution. These results contribute to a better understanding of the cutaneous response to HD in the HGP model. 相似文献