全文获取类型
收费全文 | 2373篇 |
免费 | 122篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 117篇 |
妇产科学 | 120篇 |
基础医学 | 184篇 |
口腔科学 | 146篇 |
临床医学 | 145篇 |
内科学 | 448篇 |
皮肤病学 | 91篇 |
神经病学 | 119篇 |
特种医学 | 132篇 |
外国民族医学 | 1篇 |
外科学 | 469篇 |
综合类 | 38篇 |
预防医学 | 59篇 |
眼科学 | 127篇 |
药学 | 158篇 |
中国医学 | 12篇 |
肿瘤学 | 69篇 |
出版年
2024年 | 2篇 |
2023年 | 22篇 |
2022年 | 27篇 |
2021年 | 64篇 |
2020年 | 55篇 |
2019年 | 57篇 |
2018年 | 77篇 |
2017年 | 89篇 |
2016年 | 80篇 |
2015年 | 90篇 |
2014年 | 95篇 |
2013年 | 121篇 |
2012年 | 187篇 |
2011年 | 196篇 |
2010年 | 112篇 |
2009年 | 99篇 |
2008年 | 149篇 |
2007年 | 207篇 |
2006年 | 164篇 |
2005年 | 161篇 |
2004年 | 129篇 |
2003年 | 108篇 |
2002年 | 95篇 |
2001年 | 15篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1968年 | 1篇 |
排序方式: 共有2500条查询结果,搜索用时 15 毫秒
71.
Sezgin Gunes Gulgez Neslihan Taskurt Hekim Mehmet Alper Arslan Ramazan Asci 《Journal of assisted reproduction and genetics》2016,33(4):441-454
The study aims to discuss the effects of aging on the male reproductive system. A systematic review was performed using PubMed from 1980 to 2014. Aging is a natural process comprising of irreversible changes due to a myriad of endogenous and environmental factors at the level of all organs and systems. In modern life, as more couples choose to postpone having a child due to various socioeconomic reasons, research for understanding the effects of aging on the reproductive system has gained an increased importance. Paternal aging also causes genetic and epigenetic changes in spermatozoa, which impair male reproductive functions through their adverse effects on sperm quality and count as, well as, on sexual organs and the hypothalamic-pituitary-gonadal axis. Hormone production, spermatogenesis, and testes undergo changes as a man ages. These small changes lead to decrease in both the quality and quantity of spermatozoa. The offspring of older fathers show high prevalence of genetic abnormalities, childhood cancers, and several neuropsychiatric disorders. In addition, the latest advances in assisted reproductive techniques give older men a chance to have a child even with poor semen parameters. Further studies should investigate the onset of gonadal senesce and its effects on aging men. 相似文献
72.
Chronic Mastitis in Egypt and Morocco: Differentiating between Idiopathic Granulomatous Mastitis and IgG4‐Related Disease
下载免费PDF全文
![点击此处可从《The breast journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
73.
Robotics in otolaryngology and head and neck surgery: Recommendations for training and credentialing: A report of the 2015 AHNS education committee,AAO‐HNS robotic task force and AAO‐HNS sleep disorders committee
下载免费PDF全文
![点击此处可从《Head & neck》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Neil D. Gross MD F. Christopher Holsinger MD J. Scott Magnuson MD Umamaheswar Duvvuri MD PhD Eric M. Genden MD Tamer AH. Ghanem MD PhD Kathleen L. Yaremchuk MD David Goldenberg MD Matthew C. Miller MD Eric J. Moore MD Luc GT. Morris MD James Netterville Gregory S. Weinstein MD Jeremy Richmon MD 《Head & neck》2016,38(Z1):E151-E158
74.
Baculovirus-insect cell system (BICS) is considered one of the most efficient eukaryotic gene expression systems. This system has also been used for producing different recombinant baculoviruses with increased insect toxicity as potential biopesticides. Establishing a universal gene silencing (UGS) system is very important due to the increasing number of studies using RNA interference (RNAi) with BICS. In this work, the enhanced green fluorescent protein (EGFP) was used as the RNAi consistent target sequence located downstream of a depressant insect-neurotoxin gene, LqqIT2 used as a model of the gene of interest. Small interfering RNA (siRNA) and inverted repeats of EGFP gene (IR-EG) were examined in targeting the EGFP-LqqIT2 (EL)-fusion mRNA or LqqIT2-EGFP (LE)-bicistronic mRNA for degradation. Suppression efficiencies using these inducers were examined transiently and stably in uninfected and infected insect Sf9 cells. Moreover, RNAi showed persistence for 4 and 8 days in baculovirus-infected as well as uninfected Sf9 cells, respectively. Bicistronic RNA seems an efficient way to lower cost and effort of the gene silencing approach while maintaining the biological activity of the protein of interest when the RNAi is not in use. 相似文献
75.
Derek Weycker Ahuva Hanau Alexander Lonshteyn Charles Bowers Mark Bensink Tamer Garawin 《Current medical research and opinion》2018,34(9):1705-1711
Background: Two recent evaluations reported that risk of febrile neutropenia (FN) may be higher when pegfilgrastim prophylaxis (PP) is administered on same day as chemotherapy rather than per recommendation (1–3 days following chemotherapy). Such evidence is based largely on the experience of younger privately insured adults and may not be generalizable to older patients in US clinical practice.Methods: A retrospective cohort design and data from Medicare Claims Research Identifiable Files (January 2008–September 2015) were employed. Patients were aged ≥65 years, had breast cancer or non-Hodgkin’s lymphoma, received chemotherapy with intermediate/high risk for FN, and received PP in ≥1 cycle; cycles with PP were stratified based on administration day (same-day [“Day 0”] vs. 1–3 days following chemotherapy [“Days 1–3”]) and were pooled for analyses. Adjusted odds ratios (ORs) for FN during the cycle were estimated for patients who received PP on Day 0 versus Days 1–3.Results: Study population included 65,003 patients who received PP in 261,184 cycles; in 5% of cycles, patients received PP on Day 0. Incidence proportion for FN in cycle 1 was 11.4% for Day 0 versus 8.4% for Days 1–3; adjusted OR was 1.4 (p?.001). Incidence proportion for FN when considering all cycles was 7.7% for Day 0 and 6.0% for Days 1–3; adjusted OR was 1.3 (p?.001). Adjusted ORs when considering all cycles and only inpatient FN episodes (1.3, p?.001) and the narrow definition for FN (1.5, p?.001) were similar.Conclusions: Among Medicare patients receiving chemotherapy and PP in US clinical practice, PP was administered before the recommended timing in 5% of cycles and FN incidence was significantly higher in these cycles. Along with prior research, study findings support recently updated US practice guidelines indicating that PP should be administered the day after chemotherapy. 相似文献
76.
Inan U Aydemir H Taşdemir T 《Australian endodontic journal : the journal of the Australian Society of Endodontology Inc》2007,33(1):18-22
The aim of this study was to compare the apical sealing ability of three different obturation techniques using an electrochemical evaluation and evaluating dye penetration. One hundred and thirty-two maxillary anterior teeth were randomly divided into six groups. There were 20 teeth in each group. The teeth were obturated as follows: Groups 1 and 4 with Thermafil, Groups 2 and 5 with System B, and Groups 3 and 6 with cold lateral condensation (CLC). The apical leakage in these groups was evaluated using an electrochemical method for Groups 1, 2, 3 and a dye penetration method for Groups 4, 5 and 6. In both methods, the lowest mean leakage values were observed for Thermafil and the highest were observed for the CLC groups. The difference between Thermafil and CLC was statistically significant (P < 0.05). In both groups, System B fillings showed moderate leakage and the difference was not significant with Thermafil and CLC groups. 相似文献
77.
78.
79.
Buer Sen Christopher R Paradise Zhihui Xie Jeyantt Sankaran Gunes Uzer Maya Styner Mark Meyer Amel Dudakovic Andre J van Wijnen Janet Rubin 《Journal of bone and mineral research》2020,35(6):1149-1162
During bone marrow stromal cell (BMSC) differentiation, both Wnt signaling and the development of a rigid cytoskeleton promote commitment to the osteoblastic over adipogenic lineage. β-catenin plays a critical role in the Wnt signaling pathway to facilitate downstream effects on gene expression. We show that β-catenin was additive with cytoskeletal signals to prevent adipogenesis, and β-catenin knockdown promoted adipogenesis even when the actin cytoskeleton was depolymerized. β-catenin also prevented osteoblast commitment in a cytoskeletal-independent manner, with β-catenin knockdown enhancing lineage commitment. Chromatin immunoprecipitation (ChIP)-sequencing demonstrated binding of β-catenin to the promoter of enhancer of zeste homolog 2 (EZH2), a key component of the polycomb repressive complex 2 (PRC2) complex that catalyzes histone methylation. Knockdown of β-catenin reduced EZH2 protein levels and decreased methylated histone 3 (H3K27me3) at osteogenic loci. Further, when EZH2 was inhibited, β-catenin's anti-differentiation effects were lost. These results indicate that regulating EZH2 activity is key to β-catenin's effects on BMSCs to preserve multipotentiality. © 2020 American Society for Bone and Mineral Research. 相似文献