全文获取类型
收费全文 | 23655篇 |
免费 | 1796篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 225篇 |
儿科学 | 909篇 |
妇产科学 | 621篇 |
基础医学 | 3240篇 |
口腔科学 | 668篇 |
临床医学 | 2637篇 |
内科学 | 4663篇 |
皮肤病学 | 325篇 |
神经病学 | 1920篇 |
特种医学 | 901篇 |
外科学 | 3176篇 |
综合类 | 387篇 |
一般理论 | 44篇 |
预防医学 | 2290篇 |
眼科学 | 371篇 |
药学 | 1516篇 |
1篇 | |
中国医学 | 21篇 |
肿瘤学 | 1577篇 |
出版年
2022年 | 133篇 |
2021年 | 367篇 |
2020年 | 249篇 |
2019年 | 390篇 |
2018年 | 423篇 |
2017年 | 348篇 |
2016年 | 364篇 |
2015年 | 457篇 |
2014年 | 616篇 |
2013年 | 823篇 |
2012年 | 1203篇 |
2011年 | 1311篇 |
2010年 | 700篇 |
2009年 | 602篇 |
2008年 | 1157篇 |
2007年 | 1278篇 |
2006年 | 1184篇 |
2005年 | 1155篇 |
2004年 | 1053篇 |
2003年 | 1001篇 |
2002年 | 878篇 |
2001年 | 647篇 |
2000年 | 638篇 |
1999年 | 531篇 |
1998年 | 250篇 |
1997年 | 209篇 |
1996年 | 213篇 |
1995年 | 222篇 |
1994年 | 205篇 |
1993年 | 182篇 |
1992年 | 481篇 |
1991年 | 472篇 |
1990年 | 444篇 |
1989年 | 437篇 |
1988年 | 409篇 |
1987年 | 355篇 |
1986年 | 310篇 |
1985年 | 384篇 |
1984年 | 299篇 |
1983年 | 264篇 |
1982年 | 166篇 |
1979年 | 212篇 |
1978年 | 184篇 |
1977年 | 154篇 |
1976年 | 148篇 |
1975年 | 158篇 |
1974年 | 159篇 |
1973年 | 199篇 |
1972年 | 160篇 |
1971年 | 143篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Warren JE Silver RM Dalton J Nelson LT Branch DW Porter TF 《Obstetrics and gynecology》2007,110(3):619-624
OBJECTIVE: To estimate whether polymorphisms in the collagen 1Alpha1 gene (COL1Alpha1) and the transforming growth factor-beta gene (TGF-beta;1) are more common in women with cervical insufficiency than in those without the condition. METHODS: Medical, obstetric, and family histories and blood were obtained from women with (n=121) and those without (n=165) cervical insufficiency. DNA was extracted and purified by using commercial DNA isolation kits. Samples were analyzed for variants in two genes, the COL1A1 intron 1SP1 and TGF-beta Arg-25-Pro polymorphism, by using an allele-specific polymerase chain reaction assay. RESULTS: Thirty-four of 125 (27.2%) women with cervical insufficiency had at least one first-degree female relative affected. The frequency of the homozygous TT genotype in the COL1A1 gene was increased in women with a history of cervical insufficiency compared with controls (10.8% compared with 3.1%, P=.04). The TGF-beta polymorphisms (ArgPro and ProPro) also were increased in cases (38.3% compared with 14.6%, P<.001). CONCLUSION: Over one fourth of women with cervical insufficiency have a family history of cervical insufficiency, and the COL1A1 intron 1SP1 and TGF-beta Arg-25-Pro polymorphisms are associated with the condition. These observations suggest that, in part, cervical insufficiency is mediated by genetic factors. LEVEL OF EVIDENCE: II. 相似文献
992.
993.
Wilberg A. Moncada Arita Eduardo Smelin Perdomo Domínguez Astrid Yohaly Rivera Caballero Nelson A. EspinozaMoreno Mauricio E. Zavala Galeano Barbara R. DuPont Hctor M. RamosZaldívar 《Clinical Case Reports》2022,10(4)
Less than one percent of individuals with Down syndrome exhibit mosaicism, a biological phenomenon that describes an individual who has two or more genetically distinct cell lines. The percentage of mosaicism in different tissues can impact the presence of clinical findings and hinder cytogenetic diagnosis. We report a case of mosaicism for trisomy 21 diagnosed after multi‐tissue cytogenetic analysis of peripheral blood and buccal mucosa, associated with significant intellectual disability, dysmorphic facial features, congenital heart defects, macropenis, and imperforate anus. 相似文献
994.
Enhanced Recovery After Surgery (ERAS) is a global surgical quality improvement program that started in colorectal surgery and has now expanded to numerous specialties, including gynecologic oncology. ERAS guidelines comprise multidisciplinary, evidence-based recommendations in the preoperative, intraoperative, and postoperative period; these interventions broadly encompass patient education, anesthetic choice, multimodal pain control, avoidance of unnecessary drains, maintenance of nutrition, and prevention of emesis. Implementation of ERAS has been shown to be associated with improved clinical outcomes (length of hospital stay, complications, readmissions) and cost. Marx and colleagues first demonstrated the feasibility of ERAS in gynecologic oncology in 2003; since then, over 30 comparative studies and 4 guidelines have been published encompassing major gynecologic surgery, cytoreductive surgery, and vulvar/vaginal surgery. Implementation of ERAS in gynecologic oncology has been demonstrated to provide improvements in length of stay, complications, cost, opioid use, and patient satisfaction. Increased compliance with ERAS guidelines has been associated with greater improvement in outcomes. 相似文献
995.
Jane L. Bilett Nelson F. Jones Leighton C. Whitaker 《Journal of clinical psychology》1982,38(2):232-243
Literature that addresses the diagnosis of mental disorder in adolescents strongly suggests that it may not be possible to do so. Schizophrenic thinking, in particular, has been seen as generally characteristic of adolescents. Making judgments of specific responses from the Rorschach, the WAIS, and the WIST, 10 expert clinicians were able to make judgments with regard to 12 adolescents in the 16–19 age range that were suprisingly accurate in discriminating among schizophrenics, nonschizophrenic hospitalized adolescents, and a normal control group. Results indicate that schizophrenic thinking is not necessarily characteristic of adolescents and that information from the WIST may be helpful in identifying schizophrenic adolescents. 相似文献
996.
Validation of the HFA‐PEFF score for the diagnosis of heart failure with preserved ejection fraction
997.
998.
Ericles Otvio Santos Pedro Lima Emmerich Oliveira Thaís Pereira de Mello Andr Luis Souza dos Santos Carlos Nelson Elias Sung-Hwan Choi Amanda Cunha Regal de Castro 《Materials》2022,15(2)
The wide application of additive manufacturing in dentistry implies the further investigation into oral micro-organism adhesion and biofilm formation on vat-photopolymerization (VP) dental resins. The surface characteristics and microbiological analysis of a VP dental resin, printed at resolutions of 50 μm (EG-50) and 100 μm (EG-100), were evaluated against an auto-polymerizing acrylic resin (CG). Samples were evaluated using a scanning electron microscope, a scanning white-light interferometer, and analyzed for Candida albicans (CA) and Streptococcus mutans (SM) biofilm, as well as antifungal and antimicrobial activity. EG-50 and EG-100 exhibited more irregular surfaces and statistically higher mean (Ra) and root-mean-square (rms) roughness (EG-50-Ra: 2.96 ± 0.32 µm; rms: 4.05 ± 0.43 µm/EG-100-Ra: 3.76 ± 0.58 µm; rms: 4.79 ± 0.74 µm) compared to the CG (Ra: 0.52 ± 0.36 µm; rms: 0.84 ± 0.54 µm) (p < 0.05). The biomass and extracellular matrix production by CA and SM and the metabolic activity of SM were significantly decreased in EG-50 and EG-100 compared to CG (p < 0.05). CA and SM growth was inhibited by the pure unpolymerized VP resin (48 h). EG-50 and EG-100 recorded a greater irregularity, higher surface roughness, and decreased CA and SM biofilm formation over the CG. 相似文献
999.
Chii-Yuh Kuo Tilo Gerhardt Juan Bolivar Nelson Claure Eduardo Bancalari 《Pediatric pulmonology》1996,22(1):35-43
We studied the effect of leaks around the endotracheal tube (ETT) on the measurement of pulmonary mechanics during mechanical ventilation. We also evaluated the influence of different ventilator settings on the magnitude of leak. An adjustable leak was created at the end of the ETT in a lung model with constant compliance. Flow, tidal volume, and pressure changes were measured above and below the leak. Compliance (Ci) and resistance (Ri) during inspiration were determined by linear regression analysis (LRA) using the equation of motion and the Mead and Wittenberger method (MWM). The ventilatory change that influenced the degree of leak most was prolongation of inspiratory time (Ti). The presence of a leak around the ETT resulted in an overestimation of the Ci and Ri values, which was proportional to the size of the leak. This overestimation was also influenced by the method used to determine Ci and Ri. Because the contribution of the leak to the tidal volume progressively increased as inspiration continued, methods of analysis that depended mainly on measurement points at the end of inspiration showed a larger deviation from the true Ci and Ri values than methods mainly influenced by measurement points at the beginning of inspiration. Because of this, shortening of inspiration, or analysis of points at the beginning of inspiration reduces the error in the measurements of Ci and Ri when a leak is present. Breaths with a large leak should be excluded from any analysis of pulmonary mechanics. Pediatr Pulmonol. 1996; 22:35–43. © 1996 Wiley-Liss, Inc. 相似文献
1000.