全文获取类型
收费全文 | 2225篇 |
免费 | 167篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 81篇 |
妇产科学 | 47篇 |
基础医学 | 289篇 |
口腔科学 | 29篇 |
临床医学 | 405篇 |
内科学 | 394篇 |
皮肤病学 | 46篇 |
神经病学 | 211篇 |
特种医学 | 45篇 |
外科学 | 208篇 |
综合类 | 34篇 |
一般理论 | 1篇 |
预防医学 | 237篇 |
眼科学 | 37篇 |
药学 | 152篇 |
中国医学 | 2篇 |
肿瘤学 | 152篇 |
出版年
2023年 | 17篇 |
2022年 | 41篇 |
2021年 | 70篇 |
2020年 | 43篇 |
2019年 | 52篇 |
2018年 | 86篇 |
2017年 | 58篇 |
2016年 | 49篇 |
2015年 | 50篇 |
2014年 | 86篇 |
2013年 | 125篇 |
2012年 | 164篇 |
2011年 | 177篇 |
2010年 | 90篇 |
2009年 | 63篇 |
2008年 | 138篇 |
2007年 | 126篇 |
2006年 | 141篇 |
2005年 | 159篇 |
2004年 | 134篇 |
2003年 | 105篇 |
2002年 | 97篇 |
2001年 | 16篇 |
2000年 | 17篇 |
1999年 | 14篇 |
1998年 | 29篇 |
1997年 | 11篇 |
1996年 | 12篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 14篇 |
1986年 | 6篇 |
1985年 | 14篇 |
1984年 | 10篇 |
1983年 | 16篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1972年 | 10篇 |
1971年 | 7篇 |
排序方式: 共有2395条查询结果,搜索用时 13 毫秒
81.
Chithiravel Sundaresan Pierre Josse Mrio C. Vebber Jaclyn Brusso Jianping Lu Ye Tao Salima Alem Benoît H. Lessard 《RSC advances》2022,12(16):10029
Silicon phthalocyanines as ternary additives are a promising way to increase the performance of organic photovoltaics. The miscibility of the additive and the donor polymer plays a significant role in the enhancement of the device performance, therefore, ternary additives can be designed to better interact with the conjugated polymer. We synthesized N-9′-heptadecanyl-2,7-carbazole functionalized SiPc ((CBzPho)2-SiPc), a ternary additive with increased miscibility in poly[N-90-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT). The resulting additive was included into PCDTBT and [6,6]-phenyl C71 butyric acid methyl ester as bulk (PC71BM) heterojunction OPV devices as a ternary additive. While the (CBzPho)2-SiPc demonstrated strong EQE >30% contribution in the range of 650–730 nm, the overall performance was reduced because (CBzPho)2-SiPc acted as a hole trap due to its high-lying HOMO energy level. This study demonstrates the importance of the solubility, miscibility, and energy level engineering of the ternary additive when designing organic photovoltaic devices.Silicon phthalocyanines with carbazole axial functional groups were synthesized to improve the miscibility in PCDTBT and for use as ternary additives in organic photovoltaics. 相似文献
82.
Jaclyn A. Shepard Marc Breton Revital Nimri Joseph T. F. Roberts Timothy Street David Klonoff Katharine Barnard-Kelly 《Journal of diabetes science and technology》2022,16(1):224
A growing number of individuals with type 1 diabetes are choosing to use “do-it-yourself” artificial pancreas systems (DIY APS) to support their diabetes self-management. Observational and self-report data of glycemic benefits of DIY APS are promising; however, without rigorous clinical trials or regulation from governing bodies, liability and user safety continue to be central concerns for stakeholders. Despite DIY APS having been used for several years now, there are no guidelines to assist users and healthcare professionals in addressing DIY APS use in routine clinical care. This commentary reports key stakeholders’ perspectives presented at the annual Advanced Technologies and Treatments in Diabetes conference in February 2020. Important considerations to inform the development of clinical care guidelines are also presented to generate further debate. 相似文献
83.
84.
Wei Fang Dai Claire de Oliveira Scott Blommaert Reka E. Pataky David Tran Zeb Aurangzeb Cynthia Kendell Chris Folkins Chandy Somayaji Jeff Dowden Winson Cheung Erin Strumpf Jaclyn M. Beca Carol McClure Robin Urquhart James Ted McDonald Riaz Alvi Donna Turner Stuart Peacock Avram Denburg Rebecca E. Mercer Caroline Muoz Ambica Parmar Mina Tadrous Pam Takhar Kelvin K. W. Chan 《Current oncology (Toronto, Ont.)》2022,29(3):2046
Canadian provinces routinely collect patient-level data for administrative purposes. These real-world data (RWD) can be used to generate real-world evidence (RWE) to inform clinical care and healthcare policy. The CanREValue Collaboration is developing a framework for the use of RWE in cancer drug funding decisions. A Data Working Group (WG) was established to identify data assets across Canada for generating RWE of oncology drugs. The mapping exercise was conducted using an iterative scan with informant surveys and teleconference. Data experts from ten provinces convened for a total of three teleconferences and two in-person meetings from March 2018 to September 2019. Following each meeting, surveys were developed and shared with the data experts which focused on identifying databases and data elements, as well as a feasibility assessment of conducting RWE studies using existing data elements and resources. Survey responses were compiled into an interim data report, which was used for public stakeholder consultation. The feedback from the public consultation was used to update the interim data report. We found that databases required to conduct real-world studies are often held by multiple different data custodians. Ninety-seven databases were identified across Canada. Provinces held on average 9 distinct databases (range: 8–11). An Essential RWD Table was compiled that contains data elements that are necessary, at a minimal, to conduct an RWE study. An Expanded RWD Table that contains a more comprehensive list of potentially relevant data elements was also compiled and the availabilities of these data elements were mapped. While most provinces have data on patient demographics (e.g., age, sex) and cancer-related variables (e.g., morphology, topography), the availability and linkability of data on cancer treatment, clinical characteristics (e.g., morphology and topography), and drug costs vary among provinces. Based on current resources, data availability, and access processes, data experts in most provinces noted that more than 12 months would be required to complete an RWE study. The CanREValue Collaboration’s Data WG identified key data holdings, access considerations, as well as gaps in oncology treatment-specific data. This data catalogue can be used to facilitate future oncology-specific RWE analyses across Canada. 相似文献
85.
86.
Janis E. Gerkensmeyer Cynthia S. Johnson Eric L. Scott Ukamaka M. Oruche Laura M. Lindsey Joan K. Austin Susan M. Perkins 《Archives of Psychiatric Nursing》2013
Building Our Solutions and Connections (BOSC) focused on enhancing problem-solving skills (PSS) of primary caregivers of children with mental health problems. Aims were determining feasibility, acceptability, and effect size (ES) estimates for depression, burden, personal control, and PSS. Methods: Caregivers were randomized to BOSC (n = 30) or wait-list control (WLC) groups (n = 31). Data were collected at baseline, post-intervention, and 3 and 6 months post-intervention. Results: Three-months post-intervention, ES for burden and personal control were .07 and .08, respectively. ES for depressed caregivers for burden and personal control were 0.14 and 0.19, respectively. Conclusions: Evidence indicates that the intervention had desired effects. 相似文献
87.
88.
Embryonic Stem Cell Marker Expression Pattern in Human Mesenchymal Stem Cells Derived from Bone Marrow, Adipose Tissue, Heart and Dermis 总被引:2,自引:0,他引:2
Una Riekstina Inese Cakstina Vadims Parfejevs Martin Hoogduijn Georgs Jankovskis Indrikis Muiznieks Ruta Muceniece Janis Ancans 《Stem cell reviews》2009,5(4):378-386
Mesenchymal stem cells (MSCs) have been isolated from a variety of human tissues, e.g., bone marrow, adipose tissue, dermis,
hair follicles, heart, liver, spleen, dental pulp. Due to their immunomodulatory and regenerative potential MSCs have shown
promising results in preclinical and clinical studies for a variety of conditions, such as graft versus host disease (GvHD),
Crohn’s disease, osteogenesis imperfecta, cartilage damage and myocardial infarction. MSC cultures are composed of heterogeneous
cell populations. Complications in defining MSC arise from the fact that different laboratories have employed different tissue
sources, extraction, and cultivation methods. Although cell-surface antigens of MSCs have been extensively explored, there
is no conclusive evidence that unique stem cells markers are associated with these adult cells. Therefore the aim of this
study was to examine expression of embryonic stem cell markers Oct4, Nanog, SOX2, alkaline phosphatase and SSEA-4 in adult
mesenchymal stem cell populations derived from bone marrow, adipose tissue, dermis and heart. Furthermore, we tested whether
human mesenchymal stem cells preserve tissue-specific differences under in vitro culture conditions. We found that bone marrow
MSCs express embryonic stem cell markers Oct4, Nanog, alkaline phosphatase and SSEA-4, adipose tissue and dermis MSCs express
Oct4, Nanog, SOX2, alkaline phosphatase and SSEA-4, whereas heart MSCs express Oct4, Nanog, SOX2 and SSEA-4. Our results also
indicate that human adult mesenchymal stem cells preserve tissue-specific differences under in vitro culture conditions during
early passages, as shown by distinct germ layer and embryonic stem cell marker expression patterns. Studies are now needed
to determine the functional role of embryonic stem cell markers Oct4, Nanog and SOX2 in adult human MSCs. 相似文献
89.
Staci D. Bilbo Susan H. Smith Jaclyn M. Schwarz 《Journal of neuroimmune pharmacology》2012,7(1):24-41
Cognitive decline is a common problem of aging. Whereas multiple neural and glial mechanisms may account for these declines,
microglial sensitization and/or dystrophy has emerged as a leading culprit in brain aging and dysfunction. However, glial
activation is consistently observed in normal brain aging as well, independent of frank neuroinflammation or functional impairment.
Such variability suggests the existence of additional vulnerability factors that can impact neuronal-glial interactions and
thus overall brain and cognitive health. The goal of this review is to elucidate our working hypothesis that an individual’s
risk or resilience to neuroinflammatory disorders and poor cognitive aging may critically depend on their early life experience, which can change immune reactivity within the brain for the remainder of the lifespan. For instance, early-life infection
in rats can profoundly disrupt memory function in young adulthood, as well as accelerate age-related cognitive decline, both
of which are linked to enduring changes in glial function that occur in response to the initial infection. We discuss these
findings within the context of the growing literature on the role of immune molecules and neuroimmune crosstalk in normal
brain development. We highlight the intrinsic factors (e.g., chemokines, hormones) that regulate microglial development and
their colonization of the embryonic and postnatal brain, and the capacity for disruption or “re-programming” of this crucial
process by external events (e.g., stress, infection). An impact on glia, which in turn alters neural development, has the
capacity to profoundly impact cognitive and mental health function at all stages of life. 相似文献
90.
Elizabeth Goldmuntz MD Prasuna Paluru MS Joseph Glessner BS Hakon Hakonarson MD PhD Jaclyn A. Biegel PhD Peter S. White PhD Xiaowu Gai PhD Tamim H. Shaikh PhD 《Congenital heart disease》2011,6(6):592-602
Objective. Multiple genetic syndromes are caused by recurrent chromosomal microdeletions or microduplications. The increasing use of high‐resolution microarrays in clinical analysis has allowed the identification of previously undetectable submicroscopic copy number variants (CNVs) associated with genetic disorders. We hypothesized that patients with congenital heart disease and additional dysmorphic features or other anomalies would be likely to harbor previously undetected CNVs, which might identify new disease loci or disease‐related genes for various cardiac defects. Design. Copy number analysis with single nucleotide polymorphism‐based, oligonucleotide microarrays was performed on 58 patients with congenital heart disease and other dysmorphic features and/or other anomalies. The observed CNVs were validated using independent techniques and validated CNVs were further analyzed using computational algorithms and comparison with available control CNV datasets in order to assess their pathogenic potential. Results. Potentially pathogenic CNVs were detected in twelve of 58 patients (20.7%), ranging in size from 240 Kb to 9.6 Mb. These CNVs contained between 1 and 55 genes, including NRP1, NTRK3, MESP1, ADAM19, and HAND1, all of which are known to participate in cardiac development. Conclusions. Genome‐wide analysis in patients with congenital heart disease and additional phenotypes has identified potentially pathogenic CNVs affecting genes involved in cardiac development. The identified variant loci and the genes within them warrant further evaluation in similarly syndromic and nonsyndromic cardiac cohorts. 相似文献