全文获取类型
收费全文 | 3842篇 |
免费 | 445篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 113篇 |
妇产科学 | 86篇 |
基础医学 | 542篇 |
口腔科学 | 126篇 |
临床医学 | 527篇 |
内科学 | 867篇 |
皮肤病学 | 77篇 |
神经病学 | 397篇 |
特种医学 | 76篇 |
外科学 | 371篇 |
综合类 | 20篇 |
一般理论 | 1篇 |
预防医学 | 430篇 |
眼科学 | 88篇 |
药学 | 276篇 |
中国医学 | 4篇 |
肿瘤学 | 270篇 |
出版年
2023年 | 47篇 |
2022年 | 77篇 |
2021年 | 144篇 |
2020年 | 82篇 |
2019年 | 117篇 |
2018年 | 121篇 |
2017年 | 128篇 |
2016年 | 128篇 |
2015年 | 145篇 |
2014年 | 157篇 |
2013年 | 215篇 |
2012年 | 242篇 |
2011年 | 242篇 |
2010年 | 142篇 |
2009年 | 151篇 |
2008年 | 201篇 |
2007年 | 202篇 |
2006年 | 176篇 |
2005年 | 169篇 |
2004年 | 157篇 |
2003年 | 138篇 |
2002年 | 144篇 |
2001年 | 67篇 |
2000年 | 59篇 |
1999年 | 79篇 |
1998年 | 55篇 |
1997年 | 47篇 |
1996年 | 39篇 |
1995年 | 62篇 |
1994年 | 34篇 |
1993年 | 23篇 |
1992年 | 30篇 |
1991年 | 40篇 |
1990年 | 29篇 |
1989年 | 27篇 |
1988年 | 28篇 |
1987年 | 22篇 |
1986年 | 30篇 |
1985年 | 20篇 |
1984年 | 18篇 |
1983年 | 15篇 |
1982年 | 26篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 24篇 |
1978年 | 15篇 |
1976年 | 13篇 |
1975年 | 12篇 |
1974年 | 12篇 |
1972年 | 17篇 |
排序方式: 共有4299条查询结果,搜索用时 62 毫秒
151.
Peristera Paschou Dongmei Yu Gloria Gerber Patrick Evans Fotis Tsetsos Lea K. Davis Iordanis Karagiannidis Jonathan Chaponis Eric Gamazon Kirsten Mueller‐Vahl Manfred Stuhrmann Monika Schloegelhofer Mara Stamenkovic Johannes Hebebrand Markus Noethen Peter Nagy Csaba Barta Zsanett Tarnok Renata Rizzo Christel Depienne Yulia Worbe Andreas Hartmann Danielle C. Cath Cathy L. Budman Paul Sandor Cathy Barr Thomas Wolanczyk Harvey Singer I‐Ching Chou Marco Grados Danielle Posthuma Guy A. Rouleau Harald Aschauer Nelson B. Freimer David L. Pauls Nancy J. Cox Carol A. Mathews Jeremiah M. Scharf 《Annals of neurology》2014,76(2):310-315
Tourette syndrome (TS) is a neurodevelopmental disorder with a complex genetic etiology. Through an international collaboration, we genotyped 42 single nucleotide polymorphisms (p < 10−3) from the recent TS genomewide association study (GWAS) in 609 independent cases and 610 ancestry‐matched controls. Only rs2060546 on chromosome 12q22 (p = 3.3 × 10−4) remained significant after Bonferroni correction. Meta‐analysis with the original GWAS yielded the strongest association to date (p = 5.8 × 10−7). Although its functional significance is unclear, rs2060546 lies closest to NTN4, an axon guidance molecule expressed in developing striatum. Risk score analysis significantly predicted case–control status (p = 0.042), suggesting that many of these variants are true TS risk alleles. Ann Neurol 2014;76:310–315 相似文献
152.
Matthias Vonmoos Lea M Hulka Katrin H Preller Franziska Minder Markus R Baumgartner Boris B Quednow 《Neuropsychopharmacology》2014,39(9):2200-2210
Cocaine users consistently display cognitive impairments. However, it is still unknown whether these impairments are cocaine-induced and if they are reversible. Therefore, we examined the relation between changing intensity of cocaine use and the development of cognitive functioning within 1 year. The present data were collected as part of the longitudinal Zurich Cocaine Cognition Study (ZuCo2St). Forty-eight psychostimulant-naive controls and 57 cocaine users (19 with increased, 19 with decreased, and 19 with unchanged cocaine use) were eligible for analysis. At baseline and after a 1-year follow-up, cognitive performance was measured by a global cognitive index and four neuropsychological domains (attention, working memory, declarative memory, and executive functions), calculated from 13 parameters of a broad neuropsychological test battery. Intensity of cocaine use was objectively determined by quantitative 6-month hair toxicology at both test sessions. Substantially increased cocaine use within 1 year (mean +297%) was associated with reduced cognitive performance primarily in working memory. By contrast, decreased cocaine use (−72%) was linked to small cognitive improvements in all four domains. Importantly, users who ceased taking cocaine seemed to recover completely, attaining a cognitive performance level similar to that of the control group. However, recovery of working memory was correlated with age of onset of cocaine use—early-onset users showed hampered recovery. These longitudinal data suggest that cognitive impairment might be partially cocaine-induced but also reversible within 1 year, at least after moderate exposure. The reversibility indicates that neuroplastic adaptations underlie cognitive changes in cocaine users, which are potentially modifiable in psychotherapeutical or pharmacological interventions. 相似文献
153.
Lucijan Skubic Lea Honjak Jeannette P. Staheli Michael R. Dyen Rebecca M. Ducore Lois M. A. Colgin Anne D. Lewis Mario Poljak 《Viruses》2021,13(4)
Papillomaviruses (PVs) are a diverse group of host species-specific DNA viruses, etiologically linked with various benign and malignant neoplasms of cutaneous and mucosal epithelia. Here, we describe the detection and characterization of the first two PVs naturally infecting Japanese macaques (Macaca fuscata), including the determination of their etiological association(s) with the development of original neoplasms. The molecular and phylogenetic analyses were performed on complete genome sequences of Macaca fuscata PV types 1 (MfuPV1) and 2 (MfuPV2), which were completely sequenced in samples of a malignant oral tumor and benign anogenital neoplasm of Japanese macaques, respectively. Subsequently, two type-specific quantitative real-time PCRs were developed to estimate viral loads of MfuPV1 and MfuPV2 and to evaluate their etiological roles. The in silico molecular analyses revealed that both viral genomes encode characteristic PV proteins with conserved functional domains and have a non-coding genomic region with regulatory sequences to regulate and complete the viral life cycle. However, additional experimental evidence is needed to finally confirm the presence and biological functionality of the molecular features of both novel PVs. While MfuPV1, together with PVs identified in other macaques, is classified into the Alphapapillomavirus (Alpha-PV) species 12, MfuPV2 is most likely a representative of the novel viral species within the Alpha-PV genus. Their relatively high viral loads suggest that both PVs are etiologically linked with the development of the original neoplasms. 相似文献
154.
Kim K. B. Clemmensen MD Martin B. Blond PhD Hanan Amadid PhD Lea Bruhn MSc Dorte Vistisen PhD Kristian Karstoft PhD Frederik Persson DMSc Mathias Ried-Larsen PhD Jens J. Holst DMSc Nicolai J. Wewer Albrechtsen PhD Signe S. Torekov PhD Jonas S. Quist PhD Marit E. Jørgensen PhD Kristine Færch PhD 《Diabetes, obesity & metabolism》2021,23(2):530-539
155.
The behavior of clinical instructors, as observed by students, deeply influences their professional development. When instructors behave unprofessionally, they risk undermining the professional growth students gain from their clinical placement experience. Clinical instructors need to be aware of how their behavior can affect the students' learning process and the contributions they make to clinical nursing education. A qualitative study was performed to describe the nursing profession as perceived by students who observed their clinical instructors' behaviors during the clinical experience. In‐depth interviews of nursing students were conducted until data saturation was attained. Sixteen interviews were analyzed using an inductive content analysis methodology. The nursing profession was described by the participants through five themes as follows: the helping relationship, technical role, professional growth, working group, and contradictions and conflicts. Several examples of unprofessional behaviors on the part of the clinical instructors were reported by the respondents. The nursing profession, as perceived by nursing students, does not always reflect their expectations and their ideas related to professionalism. Universities and schools of nursing should ascertain that clinical instructors are prepared to educate students. Faculty should clearly state to students what they can expect from the clinical experience, namely, preparing students to face real working environments that do not always reflect educational philosophies. 相似文献
156.
157.
Inhibitors of Ras/Raf-1 interaction identified by two-hybrid screening revert Ras-dependent transformation phenotypes in human cancer cells 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
158.
Tom J. B. de Man Jason E. Stajich Christian P. Kubicek Clotilde Teiling Komal Chenthamara Lea Atanasova Irina S. Druzhinina Natasha Levenkova Stephanie S. L. Birnbaum Seth M. Barribeau Brooke A. Bozick Garret Suen Cameron R. Currie Nicole M. Gerardo 《Proceedings of the National Academy of Sciences of the United States of America》2016,113(13):3567-3572
Many microorganisms with specialized lifestyles have reduced genomes. This is best understood in beneficial bacterial symbioses, where partner fidelity facilitates loss of genes necessary for living independently. Specialized microbial pathogens may also exhibit gene loss relative to generalists. Here, we demonstrate that Escovopsis weberi, a fungal parasite of the crops of fungus-growing ants, has a reduced genome in terms of both size and gene content relative to closely related but less specialized fungi. Although primary metabolism genes have been retained, the E. weberi genome is depleted in carbohydrate active enzymes, which is consistent with reliance on a host with these functions. E. weberi has also lost genes considered necessary for sexual reproduction. Contrasting these losses, the genome encodes unique secondary metabolite biosynthesis clusters, some of which include genes that exhibit up-regulated expression during host attack. Thus, the specialized nature of the interaction between Escovopsis and ant agriculture is reflected in the parasite’s genome.The highly evolved agricultural lifestyle of leaf-cutting ants has attracted particular attention because these ants cultivate a symbiotic fungus that serves as their major food source. These ants cut leaves, preprocess them into small pieces, and feed them to the cultivated fungus (1). The capacity of the cultivated fungus to break down plant material gives ant agriculturalists access to the vast nutrient stores locked within neotropical plants (Fig. 1A) (2–5). The symbiosis between fungus-growing ants and their cultivated fungi has persisted for at least 50 million years (6).Open in a separate windowFig. 1.Escovopsis weberi, a specialized mycoparasite of the fungus-growing ant symbiosis, has a small genome compared with other Pezizomycotina fungi. (A) Both fungus-growing ants and the mycoparasite E. weberi use the ants’ cultivated fungi as their primary food source. The ability of the cultivated fungi to efficiently break down plant material gives both consumers access to the biomass of neotropical plants. (B) Size and protein-coding gene content of genomes of diverse fungi in the Pezizomycotina. Bayesian phylogeny estimated using partial amino acid alignments of three genes (Rpb1, Rpb2, ef1-α). All posterior probabilities are greater than 0.95. Phylogeny is rooted with Sacchormyces cervesiae (not shown). (C) Relationship between genome size and gene content. A list of genomes included in this panel is in SI Appendix, Table S1.Like human agriculture, ant agriculture is hampered by disease. The ants’ fungal crops are attacked and consumed by fungal parasites of the genus Escovopsis (Ascomycota, Pezizomycotina: anamorphic Hypocreales) (Fig. 1A) (7), which have evolved in association with the ants and their cultivated fungi (8). Escovopsis infection can have detrimental impacts on garden health and, consequently, on the survival of ant colonies (9, 10). Such mycoparasitism, the phenomenon whereby one fungus is parasitic on another fungus, is rare. It is most well-known for species from the genus Trichoderma, some of which are used as biocontrol agents for fungal diseases and others of which attack human-cultivated fungi (11–13). In contrast to Trichoderma species, however, Escovopsis species grow poorly in their hosts’ absence (SI Appendix, Figs. S1 and S2).Escovopsis species have never been isolated outside of fungus-growing ant colonies, and different strains of Escovopsis are capable of attacking the fungi grown by different fungus-growing ant species (8, 14, 15). The long-term, specialized evolutionary history of the association between Escovopsis and their hosts provides a unique venue to explore the consequences of host specialization on pathogen genome evolution. Here, we assemble and annotate the genome of a strain of Escovopsis weberi. Consistent with expectations under an evolutionary transition toward using a narrow host range, and similar to many other specialized, host-associated microbes (16, 17), E. weberi exhibits gene loss. Contrasting other fungal pathogens, the large genomes of which are expanded with genetic elements that influence host adaptation (18), the genome size of Escovopsis is small compared with those of its closest sequenced relatives. 相似文献
159.
Clinical characteristics and prognostic factors of sinonasal undifferentiated carcinoma: a multicenter study
下载免费PDF全文
![点击此处可从《International forum of allergy & rhinology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Guillaume de Bonnecaze MD MSc Benjamin Verillaud MD PhD Leonor Chaltiel PhD Sylvestre Fierens MD Mark Chapelier MD Cécile Rumeau MD MSc Olivier Malard MD PhD Marie Gavid MD MSC Xavier Dufour MD PhD Christian Righini MD PhD Emmanuelle Uro‐coste MD PhD Michel Rives MD Christine Bach MD Bertrand Baujat MD PhD François Janot MD PhD Ludovic de Gabory MD PhD Sebastien Vergez MD PhD 《International forum of allergy & rhinology》2018,8(9):1065-1072