全文获取类型
收费全文 | 9259篇 |
免费 | 769篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 115篇 |
儿科学 | 318篇 |
妇产科学 | 212篇 |
基础医学 | 1192篇 |
口腔科学 | 43篇 |
临床医学 | 1239篇 |
内科学 | 1430篇 |
皮肤病学 | 222篇 |
神经病学 | 1154篇 |
特种医学 | 208篇 |
外科学 | 905篇 |
综合类 | 122篇 |
一般理论 | 5篇 |
预防医学 | 1355篇 |
眼科学 | 137篇 |
药学 | 628篇 |
中国医学 | 10篇 |
肿瘤学 | 752篇 |
出版年
2024年 | 25篇 |
2023年 | 132篇 |
2022年 | 202篇 |
2021年 | 485篇 |
2020年 | 241篇 |
2019年 | 385篇 |
2018年 | 468篇 |
2017年 | 342篇 |
2016年 | 349篇 |
2015年 | 373篇 |
2014年 | 459篇 |
2013年 | 609篇 |
2012年 | 938篇 |
2011年 | 953篇 |
2010年 | 455篇 |
2009年 | 383篇 |
2008年 | 606篇 |
2007年 | 549篇 |
2006年 | 484篇 |
2005年 | 466篇 |
2004年 | 355篇 |
2003年 | 281篇 |
2002年 | 249篇 |
2001年 | 46篇 |
2000年 | 15篇 |
1999年 | 28篇 |
1998年 | 36篇 |
1997年 | 16篇 |
1996年 | 12篇 |
1995年 | 16篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 14篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 9篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1956年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.
93.
Erin J Aiello Shelley S Tworoger Yutaka Yasui Frank Z Stanczyk John Potter Cornelia M Ulrich Melinda Irwin Anne McTiernan 《Cancer epidemiology, biomarkers & prevention》2005,14(6):1411-1417
OBJECTIVE: Hormone therapy use has been positively associated with mammographic density in several studies. However, few studies have examined the association between endogenous hormone levels and mammographic density. Therefore, we evaluated the relationship of endogenous sex hormones, insulin-like growth factor (IGF), and lipids with mammographic density in 88 overweight, postmenopausal women not taking hormone therapy. METHODS: Percent density and dense area were evaluated as continuous measures using a computer-assisted program. We used multiple linear regression to evaluate the associations of sex hormones, IGF, and cholesterol with mammographic density, adjusting for confounders, including adiposity. We evaluated stratification by history of hormone therapy use (former versus never) and hormone therapy latency (<5 versus > or = 5 years). RESULTS: Among former hormone therapy users, mammographic density was inversely associated with circulating levels of estrone (P = 0.01), estradiol (P = 0.003), free estradiol (P = 0.004), testosterone (P = 0.04), free testosterone (P = 0.02), androstenedione (P < 0.001), dehydroepiandrosterone (P = 0.01), and the ratio of IGF-I to its binding protein (IGF-I/IGFBP-3; P = 0.04). We found similar associations when we limited the analyses to women who had used hormone therapy within the past 5 years. We also noted positive associations of mammographic density with total cholesterol (P = 0.03) and low-density lipoprotein (P = 0.03) among former hormone therapy users. No associations were noted among women who had never used hormone therapy. CONCLUSIONS: These results suggest that there is an inverse relationship between endogenous sex hormones and mammographic density in postmenopausal women among former users of hormone therapy. This is not consistent with the hormone therapy literature and should be confirmed in larger studies. 相似文献
94.
95.
96.
The ability to mentally represent actions is suggested to play a role in the online control of movement in healthy adults. Children’s movement imagery ability and online control have been shown to develop at similar nonlinear rates. The current study investigated the relationship between movement imagery and online control in children by comparing implicit and explicit movement imagery measures with the ability to make online trajectory corrections. Imagery ability was a significant predictor of children’s online control of movement once general reaching efficiency was controlled for. These findings extend the proposed relationship between movement imagery and online control. 相似文献
97.
98.
Guro Løkka Lars Austbø Knut Falk Erin Bromage Per Gunnar Fjelldal Tom Hansen Ivar Hordvik Erling Olaf Koppang 《Developmental and comparative immunology》2014
Forming a barrier to the outside world, the gut mucosa faces the challenge of absorbing nutrients and fluids while initiating immune reactions towards potential pathogens. As a continuation to our previous publication focusing on the regional intestinal morphology in wild caught post smolt and spawning Atlantic salmon, we here investigate selected immune parameters and compare wild, reared unvaccinated and vaccinated post smolts. 相似文献
99.
Inger Burnett-Zeigler Mark A. Ilgen Kipling Bohnert Erin Miller Khairul Islam Kara Zivin 《Community mental health journal》2013,49(3):303-310
In this study we examine the longitudinal effects of psychiatric and substance use disorders on employment, in an employed population. The sample included respondents to the National epidemiologic survey on alcohol related conditions (NESARC) who were employed at Wave 1 (N = 22,407). Bivariate and multivariable analyses were conducted examining the associations between 12-month and new onset 12-month psychiatric diagnoses at Wave 1 and employment status at Wave 2. Past year and new onset 12-month depression, 12-month bipolar, new onset 12-month drug abuse, and 12-month and new onset 12-month drug dependence were associated with a decreased odds of being employed at Wave 2. This study suggests that it would be beneficial for employers to support their employees in participating in mental health treatment. Additionally, understanding how psychiatric disorders influence employment over the life course might inform the development of preemptive interventions to treat mental health symptoms. 相似文献
100.
Laura F. Newell Jennifer Dunlap Ken Gatter Grover C. Bagby Richard D. Press Rachel J. Cook Luke Fletcher Jessica T. Leonard Kelli M. Leong Joseph S. Bubalo Ali Olyaei Thomas G. Deloughery Richard T. Maziarz Erin Maynard Susan L. Orloff C. Kristian Enestvedt 《American journal of transplantation》2021,21(12):3894-3906
Graft-versus-host disease after liver transplantation (LT-GVHD) is rare, frequently fatal, and associated with bone marrow failure (BMF), cytopenias, and hyperferritinemia. Given hyperferritinemia and cytopenias are present in hemophagocytic lymphohistiocytosis (HLH), and somatic mutations in hematopoietic cells are associated with hyperinflammatory responses (clonal hematopoiesis of indeterminate potential, CHIP), we identified the frequency of hemophagocytosis and CHIP mutations in LT-GVHD. We reviewed bone marrow aspirates and biopsies, quantified blood/marrow chimerism, and performed next-generation sequencing (NGS) with a targeted panel of genes relevant to myeloid malignancies, CHIP, and BMF. In all, 12 marrows were reviewed from 9 LT-GVHD patients. In all, 10 aspirates were evaluable for hemophagocytosis; 7 had adequate DNA for NGS. NGS was also performed on marrow from an LT cohort (n = 6) without GVHD. Nine of 10 aspirates in LT-GVHD patients showed increased hemophagocytosis. Five (71%) of 7 with LT-GVHD had DNMT3A mutations; only 1 of 6 in the non-GVHD LT cohort demonstrated DNMT3A mutation (p = .04). Only 1 LT-GVHD patient survived. BMF with HLH features was associated with poor hematopoietic recovery, and DNMT3A mutations were over-represented, in LT-GVHD patients. Identification of HLH features may guide prognosis and therapeutics. Further studies are needed to clarify the origin and impact of CHIP mutations on the hyperinflammatory state.