全文获取类型
收费全文 | 1106篇 |
免费 | 105篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 77篇 |
妇产科学 | 31篇 |
基础医学 | 98篇 |
口腔科学 | 36篇 |
临床医学 | 165篇 |
内科学 | 222篇 |
皮肤病学 | 27篇 |
神经病学 | 122篇 |
特种医学 | 156篇 |
外科学 | 70篇 |
综合类 | 25篇 |
预防医学 | 62篇 |
眼科学 | 12篇 |
药学 | 86篇 |
1篇 | |
中国医学 | 9篇 |
肿瘤学 | 52篇 |
出版年
2023年 | 2篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 23篇 |
2017年 | 25篇 |
2016年 | 28篇 |
2015年 | 33篇 |
2014年 | 43篇 |
2013年 | 53篇 |
2012年 | 36篇 |
2011年 | 38篇 |
2010年 | 47篇 |
2009年 | 75篇 |
2008年 | 37篇 |
2007年 | 53篇 |
2006年 | 23篇 |
2005年 | 32篇 |
2004年 | 16篇 |
2003年 | 15篇 |
2002年 | 12篇 |
2001年 | 26篇 |
2000年 | 16篇 |
1999年 | 24篇 |
1998年 | 70篇 |
1997年 | 82篇 |
1996年 | 57篇 |
1995年 | 51篇 |
1994年 | 37篇 |
1993年 | 44篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 28篇 |
1988年 | 23篇 |
1987年 | 27篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1978年 | 5篇 |
1977年 | 11篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1968年 | 3篇 |
1931年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有1257条查询结果,搜索用时 15 毫秒
1.
The midwifery art has emphasised the uniqueness of human beings throughout its Nordic history. The educated Nordic midwife has in the last decade celebrated several hundred years of memories. This article studies how the key ideas of the midwifery art and patterns of ideas become evident in the zeitgeist from the beginning of the 19th century to the millennium in the Nordic countries. The legacy and pattern of ideas of the art of midwifery are interpreted in relation to the texts of the selected historical sources and based on Ricoeur's phenomenological-hermeneutic approach to the text and further to the dedication of understanding and interpretation. The historical sources refer to unprinted primary sources from historical archives and printed secondary and tertiary sources. The patterns of ideas include a tripartite whole: the true cultivation of the head, the philosophy and aesthetics of the hand, the strength of the heart and the drive of calling. These ideas open for unique visions and attest to the evident in modern midwives. Today's midwives have academic training with examinations, and the education is based on scientific evidence. The midwife profession is authorised by the state and supervised by the authorities. 相似文献
2.
3.
Laura D. Byham‐Gray PhD RDN J. Scott Parrott PhD Emily N. Peters MPH Susan Gould Fogerite PhD Rosa K. Hand MS RDN Sean Ahrens MLS CM Andrea Fleisch Marcus PhD MPH Justin J. Fiutem MS RCEP 《JPEN. Journal of parenteral and enteral nutrition》2018,42(3):587-596
Background: Hypermetabolism is theorized in patients diagnosed with chronic kidney disease who are receiving maintenance hemodialysis (MHD). We aimed to distinguish key disease‐specific determinants of resting energy expenditure to create a predictive energy equation that more precisely establishes energy needs with the intent of preventing protein‐energy wasting. Materials and Methods: For this 3‐year multisite cross‐sectional study (N = 116), eligible participants were diagnosed with chronic kidney disease and were receiving MHD for at least 3 months. Predictors for the model included weight, sex, age, C‐reactive protein (CRP), glycosylated hemoglobin, and serum creatinine. The outcome variable was measured resting energy expenditure (mREE). Regression modeling was used to generate predictive formulas and Bland‐Altman analyses to evaluate accuracy. Results: The majority were male (60.3%), black (81.0%), and non‐Hispanic (76.7%), and 23% were ≥65 years old. After screening for multicollinearity, the best predictive model of mREE (R2 = 0.67) included weight, age, sex, and CRP. Two alternative models with acceptable predictability (R2 = 0.66) were derived with glycosylated hemoglobin or serum creatinine. Based on Bland‐Altman analyses, the maintenance hemodialysis equation that included CRP had the best precision, with the highest proportion of participants’ predicted energy expenditure classified as accurate (61.2%) and with the lowest number of individuals with underestimation or overestimation. Conclusions: This study confirms disease‐specific factors as key determinants of mREE in patients on MHD and provides a preliminary predictive energy equation. Further prospective research is necessary to test the reliability and validity of this equation across diverse populations of patients who are receiving MHD. 相似文献
4.
Molly McCarthy Ushma Upadhyay M. Antonia Biggs Renaisa Anthony Jennifer Holl Sarah CM Roberts 《Contraception》2018,97(4):303-308
Objective
Earlier pregnancy discovery is important in the context of prenatal and abortion care. We evaluated characteristics associated with later pregnancy discovery among women seeking abortion care.Study design
Data come from a survey of women seeking abortion care at four family planning facilities in Utah. The participants completed a survey during the state-mandated abortion information visit they are required to complete prior to having an abortion. The outcome in this study was pregnancy discovery before versus after 6 weeks since respondents' last menstrual period (LMP). We used logistic regression to estimate the relationship between sociodemographic and health-related independent variables of interest and pregnancy discovery before versus after 6 weeks.Results
Among the 458 women in the sample, 28% discovered their pregnancy later than 6 weeks since LMP. Most (n=366, 80%) knew the exact date of their LMP and a significant minority estimated it (n=92, 20%). Those who estimated the date of their LMP had higher odds of later pregnancy discovery than those who knew the exact date (adjusted odds ratio (aOR) = 1.81[1.07–3.07]). Those who used illicit drugs weekly, daily, or almost daily had higher odds of later pregnancy discovery (aOR=6.33[2.44, 16.40]).Conclusion
Women who did not track their menstrual periods and those who frequently used drugs had higher odds of discovering their pregnancies later.Implications
Women who estimated the date of their LMP and who frequently used drugs may benefit from strategies to help them recognize their pregnancies earlier and link them to care when they discover their pregnancies later. 相似文献5.
Marta Di Forti Hannah Sallis Fabio Allegri Antonella Trotta Laura Ferraro Simona A. Stilo Arianna Marconi Caterina La Cascia Tiago Reis Marques Carmine Pariante Paola Dazzan Valeria Mondelli Alessandra Paparelli Anna Kolliakou Diana Prata Fiona Gaughran Anthony S. David Craig Morgan Daniel Stahl Mizanur Khondoker James H. MacCabe Robin M. Murray 《Schizophrenia bulletin》2014,40(6):1509-1517
Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated. Methods: We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP. Results: Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16–1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11–1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06–1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users. Conclusions: Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users.Key words: psychotic disorders, age of onset, gender, cannabis, survival plots, drug use, high-potency cannabis 相似文献
6.
Manuela Russo Stephen Z. Levine Arsime Demjaha Marta Di Forti Stefania Bonaccorso Paul Fearon Paola Dazzan Carmine M. Pariante Anthony S. David Craig Morgan Robin M. Murray Abraham Reichenberg 《Schizophrenia bulletin》2014,40(1):111-119
Context:
Cross-sectional studies of the signs and symptoms of psychosis yield dimensional phenotypes. However, the validity and clinical utility of such dimensions remain debated. This study investigated the structure of psychotic symptomatology, the stability of the structure over time, and the concordance between symptom dimensions and categorical diagnoses.Methods:
Sample consisted of 500 first-episode psychotic patients. A cross-sectional study (N = 500) investigated the organizational structure of symptom dimensions at the onset of psychosis and its concordance with categorical diagnoses; next, a nested longitudinal study (N = 100) examined the stability of the symptom dimensions structure after 5–10 years of follow-up.Results:
Factor analyses identified 6 first-order factors (mania, negative, disorganization, depression, hallucinations, and delusions) and 2 high-order factors (affective and nonaffective psychoses). Cumulative variance accounted for by the first and high-order factors was 63%: 31% by the first-order factors and 32% by the high-order factors. The factorial structure of psychotic symptoms during first episode remained stable after 5–10 years of follow-up. The overall concordance between 4 categorical diagnostic groups (schizophrenia, mania with psychosis, psychotic depression and schizoaffective disorder) and dimensional symptom ranged from 62.2% to 73.1% (when the schizoaffective group was excluded).Conclusions:
Symptoms of psychosis assume a multidimensional hierarchical structure. This hierarchical model was stable over time and showed good concordance with categorical diagnoses. The combined use of dimensional and categorical approach to psychotic disorders would be of clinical and research utility.Key words: symptom dimensions, diagnostic classification, psychosis, DSM-5, longitudinal study 相似文献7.
Andre C. Felicio MD PhD Katherine Dinelle MSc Pankaj A. Agarwal MD DNB DM Jessamyn McKenzie LPN Nicole Heffernan RN Jeremy D. Road MD Silke Appel‐Cresswell MD Zbigniew K. Wszolek MD Matthew J. Farrer PhD Michael Schulzer MD PhD Vesna Sossi PhD A. Jon Stoessl CM MD FRCPC 《Movement disorders》2014,29(9):1197-1201
8.
9.
范春明 《中国组织工程研究与临床康复》2007,11(24):4806-4809
目的:分析胚胎干细胞和胚胎生殖细胞的生物学特性、体外培养条件、周围微环境对其增殖分化的影响,了解胚胎干细胞和胚胎生殖细胞的关系和应用前景。方法:应用计算机检索万方数据库2000/2007有关生殖细胞、胚胎干细胞、胚胎生殖细胞的相关研究文章,检索词:生殖细胞,胚胎干细胞,胚胎生殖细胞,并限定文章语言种类为中文;同时应用计算机检索PUBMED2000/2006相关文章,检索词:Germ Cells,Primordial germ cells,Embryonic stem cells,Embryonic Germ Cells,限定文章语言种类为“English”。对资料进行初审,纳入标准为有关生殖细胞、胚胎干细胞、胚胎生殖细胞的生物学特性、体外培养及生长抑制因子的作用等相关文章,并查找全文。主要选择基础研究类文章,无论有无对照组均纳入。结果:共检索到相关文章59篇,排除比较陈旧的文章,最后纳入38篇进行总结分析。胚胎干细胞与胚胎生殖细胞分别从附置前早期胚胎内细胞团和早期胎儿生殖嵴原始生殖细胞分离克隆出来,均具有自我更新、无限增殖能力及多向分化潜能,在体外培养条件下可保持稳定的二倍体核型,诱导分化后可形成3种胚胎生殖层。饲养层细胞是人胚胎生殖细胞体外培养的必要条件,常用饲养层细胞有鼠STO细胞系、鼠胚胎成纤维细胞,体外生长所需主要细胞因子包括干细胞生长因子、碱性成纤维细胞生长因子和白血病抑制因子,然而只要在培养基中加入鼠成纤维细胞的上清液和碱性成纤维细胞生长因子,胚胎干细胞可在无饲养层的条件下进行体外培养。结论:胚胎干细胞和胚胎生殖细胞具有相似的增殖特性,一定条件下可以分化为包括生殖细胞在内的所有功能细胞,并可相互转变,在胚胎发育、基因治疗、药物筛选、新药开发、生殖医学及人类疾病的移植治疗中具有广泛的应用前景。 相似文献
10.
Decision aids for localized prostate cancer treatment choice: Systematic review and meta‐analysis 下载免费PDF全文
Philippe D. Violette MD CM Thomas Agoritsas MD Paul Alexander MSc MHSc Jarno Riikonen MD PhD Henrikki Santti MD PhD Arnav Agarwal BHSc Neera Bhatnagar MLIS Philipp Dahm MD MHSc Victor Montori MD MSc Gordon H. Guyatt MD MSc Kari A. O. Tikkinen MD PhD 《CA: a cancer journal for clinicians》2015,65(3):239-251
Patients who are diagnosed with localized prostate cancer need to make critical treatment decisions that are sensitive to their values and preferences. The role of decision aids in facilitating these decisions is unknown. The authors conducted a systematic review of randomized trials of decision aids for localized prostate cancer. Teams of 2 reviewers independently identified, selected, and abstracted data from 14 eligible trials (n = 3377 men), of which 10 were conducted in North America. Of these, 11 trials compared decision aids with usual care, and 3 trials compared decision aids with other decision aids. Two trials suggested a modest positive impact on decisional regret. Results across studies varied widely for decisional conflict (4 studies), satisfaction with decision (2 studies), and knowledge (2 studies). No impact on treatment choices was observed (6 studies). In conclusion, scant evidence at high risk of bias suggests the variable impact of existing decision aids on a limited set of decisional processes and outcomes. Because current decision aids provide information but do not directly facilitate shared decision making, subsequent efforts would benefit from user‐centered design of decision aids that promote shared decision making. CA Cancer J Clin 2015;65: 239–251. © 2015 American Cancer Society. 相似文献