全文获取类型
收费全文 | 1508篇 |
免费 | 94篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 81篇 |
妇产科学 | 41篇 |
基础医学 | 233篇 |
口腔科学 | 24篇 |
临床医学 | 252篇 |
内科学 | 231篇 |
皮肤病学 | 31篇 |
神经病学 | 138篇 |
特种医学 | 8篇 |
外科学 | 104篇 |
综合类 | 26篇 |
一般理论 | 1篇 |
预防医学 | 229篇 |
眼科学 | 14篇 |
药学 | 77篇 |
中国医学 | 1篇 |
肿瘤学 | 107篇 |
出版年
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 28篇 |
2020年 | 28篇 |
2019年 | 30篇 |
2018年 | 33篇 |
2017年 | 26篇 |
2016年 | 27篇 |
2015年 | 32篇 |
2014年 | 46篇 |
2013年 | 62篇 |
2012年 | 102篇 |
2011年 | 114篇 |
2010年 | 69篇 |
2009年 | 66篇 |
2008年 | 118篇 |
2007年 | 121篇 |
2006年 | 124篇 |
2005年 | 96篇 |
2004年 | 97篇 |
2003年 | 89篇 |
2002年 | 81篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 16篇 |
1998年 | 15篇 |
1997年 | 15篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 10篇 |
1992年 | 4篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 13篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有1603条查询结果,搜索用时 14 毫秒
41.
Elizabeth R. Crais Cara S. McComish Betsy P. Humphreys Linda R. Watson Grace T. Baranek J. Steven Reznick Rob B. Christian Marian Earls 《Journal of autism and developmental disorders》2014,44(9):2311-2328
This study explored North Carolina pediatric healthcare professional’s (PHP) perceptions of screening 12–18 month old infants for Autism Spectrum Disorder (ASD). Eight focus groups (66 PHPs) were conducted across practice settings. The purpose was to explore PHP’s perspectives to: inform development of ASD screening tools and ultimately impact their use in PHP settings. PHPs reported concerns, barriers, and the need for research to support early ASD screening. Additionally, they expressed the need for: (a) clear “red flags” of ASD for 12–18 month olds; (b) socioculturally sensitive and effective screening tools; (c) effective early interventions; (d) systems to handle potential increases in referrals; and (e) continuing education. PHPs also demonstrated preferences about screening tool characteristics and processes for enhancing screening efforts. 相似文献
42.
Joey Ton Danielle Perry Betsy Thomas G. Michael Allan Adrienne J. Lindblad James McCormack Michael R. Kolber Scott Garrison Samantha Moe Rodger Craig Nicolas Dugr Karenn Chan Caitlin R. Finley Rhonda Ting Christina S. Korownyk 《Canadian family physician Médecin de famille canadien》2020,66(3):e89
ObjectiveTo determine how many patients with chronic osteoarthritis pain respond to various non-surgical treatments.Data sourcesPubMed and the Cochrane Library.Study selection Published systematic reviews of randomized controlled trials (RCTs) that included meta-analysis of responder outcomes for at least 1 of the following interventions were included: acetaminophen, oral nonsteroidal anti-inflammatory drugs (NSAIDs), topical NSAIDs, serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants, cannabinoids, counseling, exercise, platelet-rich plasma, viscosupplementation, glucosamine, chondroitin, intra-articular corticosteroids, rubefacients, or opioids.Synthesis In total, 235 systematic reviews were included. Owing to limited reporting of responder meta-analyses, a post hoc decision was made to evaluate individual RCTs with responder analysis within the included systematic reviews. New meta-analyses were performed where possible. A total of 155 RCTs were included. Interventions that led to more patients attaining meaningful pain relief compared with control included exercise (risk ratio [RR] of 2.36; 95% CI 1.79 to 3.12), intra-articular corticosteroids (RR = 1.74; 95% CI 1.15 to 2.62), SNRIs (RR = 1.53; 95% CI 1.25 to 1.87), oral NSAIDs (RR = 1.44; 95% CI 1.36 to 1.52), glucosamine (RR = 1.33; 95% CI 1.02 to 1.74), topical NSAIDs (RR = 1.27; 95% CI 1.16 to 1.38), chondroitin (RR = 1.26; 95% CI 1.13 to 1.41), viscosupplementation (RR = 1.22; 95% CI 1.12 to 1.33), and opioids (RR = 1.16; 95% CI 1.02 to 1.32). Preplanned subgroup analysis demonstrated no effect with glucosamine, chondroitin, or viscosupplementation in studies that were only publicly funded. When trials longer than 4 weeks were analyzed, the benefits of opioids were not statistically significant.ConclusionInterventions that provide meaningful relief for chronic osteoarthritis pain might include exercise, intra-articular corticosteroids, SNRIs, oral and topical NSAIDs, glucosamine, chondroitin, viscosupplementation, and opioids. However, funding of studies and length of treatment are important considerations in interpreting these data. 相似文献
43.
44.
45.
46.
Betsy A. Hosler Peter C. Sapp Ralph Berger Gilmore O'Neill Khemissa Bejaoui Mongi Ben Hamida Faycal Hentati Wendy Chin Diane McKenna-Yasek Jonathan L. Haines David Patterson H. Robert Horvitz R. H. Brown Jr. C. B. Day 《Neurogenetics》1998,2(1):34-42
Amyotrophic lateral sclerosis (ALS) is a progressive degenerative neuromuscular disease that shows familial, autosomal dominant
inheritance in 10%–15% of cases. Previous genetic analysis of one large family linked a recessive form of familial ALS (FALS-AR
type 3) to the chromosome 2q33–35 region. Using additional polymorphic markers, we have narrowed the size of the linked region
to approximately 1.7 cM by linkage and haplotype analysis. We have also established a yeast artificial chromosome contig across
the locus that covers an approximate physical distance of 3 million bases. Based on this contig, genes and expressed sequences
that map near the 2q33 region have been examined to determine whether they are located within this ALS2 candidate locus. Five identified genes and 34 expressed sequence tags map within the region defined by crossover analysis
and merit further consideration as candidate genes for this disease.
Accepted: July 15, 1998 / Published online: October 28, 1998 相似文献
47.
Capparelli EV Mirochnick M Dankner WM Blanchard S Mofenson L McSherry GD Gay H Ciupak G Smith B Connor JD;Pediatric AIDS Clinical Trials Group Investigators 《The Journal of pediatrics》2003,142(1):47-52
OBJECTIVE: To determine zidovudine pharmacokinetics and tolerance in premature human human immunodeficiency virus-exposed infants. STUDY DESIGN: Pediatric AIDS Clinical Trials Group Study 331 was a multicentered prospective, open-label study of the use of zidovudine in premature infants. Thirty-eight infants <35 weeks' gestational age (GA) were studied while receiving zidovudine 1.5 mg/kg every 12 hours until 2 weeks of age, then 2.0 mg/kg every 8 hours until 6 weeks of age. Population pharmacokinetics were evaluated at 1, 2, and 4 weeks' postnatal age; zidovudine doses were adjusted to maintain troughs <3 microM. RESULTS: Zidovudine clearance was lower than reported in term infants at similar postnatal ages. Nine premature infants required dose reduction because of high levels (7/19 <30 weeks' and 2/19 >/=30 weeks' GA). Postnatal age, GA, serum creatinine, and furosemide use independently predicted zidovudine clearance. Zidovudine was generally well tolerated in this high-risk population. CONCLUSIONS: Zidovudine clearance is greatly reduced in premature infants. We recommend the following zidovudine dosing schedule in this population: 1.5 mg/kg (intravenous) or 2.0 mg/kg (oral) every 12 hours increased to every 8 hours at 2 weeks of age (>/=30 weeks' GA) or at 4 weeks (<30 weeks' GA). 相似文献
48.
Talarico S Cave MD Marrs CF Foxman B Zhang L Yang Z 《Journal of clinical microbiology》2005,43(10):4954-4960
PE_PGRS33, one of about 60 PE_PGRS genes in the Mycobacterium tuberculosis genome, encodes a surface-expressed protein that may be involved in the antigenic variation of M. tuberculosis strains and evasion of the host immune system. While genetic differences between the PE_PGRS33 genes of H37Rv and CDC1551 have been noted, genetic variation in this gene among clinical isolates has not been evaluated. In order to gain a better understanding of the genetic basis for the role of PE_PGRS in antigenic variation and evasion of the host immune system, we investigated the genetic diversity of the PE_PGRS33 gene among 123 clinical M. tuberculosis isolates from a population-based study, using PCR and DNA sequencing. The 123 isolates belonged to principal genetic groups 1, 2, and 3 and had IS6110 copy numbers ranging from 1 to 22. Eighty-four (68.3%) of the 123 isolates were found to have at least one sequence variation in the PE_PGRS33 gene, relative to that of H37Rv. Twenty-five different sequence variations were observed and included three insertions (ranging from 9 to 87 bp), nine deletions (ranging from 1 to 273 bp), one insertion-and-deletion event, and 12 single-nucleotide polymorphisms (six synonymous and six nonsynonymous). Analysis of the relationships among the different PE_PGRS33 gene sequence variations suggests that polymorphisms in the gene are shifting along evolutionary lineages. The observed genetic diversity of the PE_PGRS33 gene supports its role in antigenic variation and can serve as a basis for future investigations of the function of the PE_PGRS33 gene among clinical isolates. 相似文献
49.
Jing Xu Fuhua Xu John H. Letaw Byung S. Park Robert P. Searles Betsy M. Ferguson 《Journal of assisted reproduction and genetics》2016,33(12):1665-1675
Purpose
The main goals of this study were to investigate the expression of anti-Müllerian hormone (AMH) and its receptor (AMHR2) during follicular development in primates, and to evaluate the potential of AMH as a biomarker for follicle growth and oocyte maturation in vitro.Methods
The mRNA and protein expression of AMH and AMHR2 were determined using isolated follicles and ovarian sections from rhesus macaques (n?=?4) by real-time PCR and immunohistochemistry, respectively. Isolated secondary follicles were cultured individually. Follicle growth and media AMH concentrations were assessed by ELISA. The mRNA expression profiles, obtained from RNA sequencing, of in vitro- and in vivo-developed antral follicles were compared. Secondary follicles from additional animals (n?=?35) were cultured. Follicle growth, oocyte maturation, and media AMH concentrations were evaluated for forecasting follicular development in vitro by AMH levels.Results
AMH immunostaining was heterogeneous in the population of preantral follicles that were also stained for AMHR2. The mRNA expression profiles were comparable between in vivo- and in vitro-developed follicles. AMH levels produced by growing follicles were higher than those of nongrowing follicles in culture. With a cutoff value of 1.40 ng/ml, 85 % of nongrowing follicles could be identified while eliminating only 5 % of growing follicles. Growing follicles that generated metaphase II-stage oocytes secreted greater amounts of AMH than did those yielding immature germinal vesicle-stage oocytes.Conclusions
AMH, co-expressed with AMHR2, was produced heterogeneously by preantral follicles in macaques with levels correlated positively with follicle growth and oocyte maturation. AMH may serve as a biomarker for primate follicular development in vitro.50.
Betsy R Maller Schulman Aurora Esquela-Kerscher Frank J Slack 《Developmental dynamics》2005,234(4):1046-1054
In C. elegans, heterochronic genes control the timing of cell fate determination during development. Two heterochronic genes, let-7 and lin-4, encode microRNAs (miRNAs) that down-regulate a third heterochronic gene lin-41 by binding to complementary sites in its 3'UTR. let-7 and lin-4 are conserved in mammals. Here we report the cloning and sequencing of mammalian lin-41 orthologs. We find that mouse and human lin-41 genes contain predicted conserved complementary sites for let-7 and the lin-4 ortholog, mir-125, in their 3'UTRs. Mouse lin-41 (Mlin-41) is temporally expressed in developing mouse embryos, most dramatically in the limb buds. Mlin-41 is down-regulated during mid-embryogenesis at the time when mouse let-7c and mir-125 RNA levels are up-regulated. Our results suggest that mammalian lin-41 is temporally regulated by miRNAs in order to direct key developmental events such as limb formation. 相似文献