全文获取类型
收费全文 | 34555篇 |
免费 | 2719篇 |
国内免费 | 420篇 |
专业分类
耳鼻咽喉 | 363篇 |
儿科学 | 1015篇 |
妇产科学 | 616篇 |
基础医学 | 4978篇 |
口腔科学 | 519篇 |
临床医学 | 3260篇 |
内科学 | 7403篇 |
皮肤病学 | 763篇 |
神经病学 | 2596篇 |
特种医学 | 1297篇 |
外国民族医学 | 16篇 |
外科学 | 4286篇 |
综合类 | 1285篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 2710篇 |
眼科学 | 706篇 |
药学 | 2596篇 |
6篇 | |
中国医学 | 622篇 |
肿瘤学 | 2654篇 |
出版年
2023年 | 272篇 |
2022年 | 668篇 |
2021年 | 1101篇 |
2020年 | 681篇 |
2019年 | 859篇 |
2018年 | 1056篇 |
2017年 | 762篇 |
2016年 | 760篇 |
2015年 | 926篇 |
2014年 | 1188篇 |
2013年 | 1541篇 |
2012年 | 2210篇 |
2011年 | 2214篇 |
2010年 | 1365篇 |
2009年 | 1137篇 |
2008年 | 1636篇 |
2007年 | 1666篇 |
2006年 | 1599篇 |
2005年 | 1503篇 |
2004年 | 1337篇 |
2003年 | 1273篇 |
2002年 | 1203篇 |
2001年 | 1115篇 |
2000年 | 1101篇 |
1999年 | 978篇 |
1998年 | 349篇 |
1997年 | 300篇 |
1996年 | 265篇 |
1995年 | 211篇 |
1994年 | 208篇 |
1993年 | 175篇 |
1992年 | 518篇 |
1991年 | 499篇 |
1990年 | 475篇 |
1989年 | 432篇 |
1988年 | 452篇 |
1987年 | 381篇 |
1986年 | 372篇 |
1985年 | 365篇 |
1984年 | 255篇 |
1983年 | 187篇 |
1982年 | 119篇 |
1981年 | 103篇 |
1979年 | 210篇 |
1978年 | 111篇 |
1977年 | 124篇 |
1976年 | 113篇 |
1974年 | 130篇 |
1972年 | 128篇 |
1969年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
951.
Chasseigne G Ligneau C Grau S Le Gall A Roque M Mullet E 《Experimental aging research》2004,30(1):23-45
The objective of the study was to examine some of the conditions under which elderly people are able to learn probabilistic inverse relationships and when this type of learning is no longer possible. Two kind of tasks were used: (a) two single-cue learning tasks with either direct or inverse relationships (the Single-Cue Probability Learning paradigm), and (b) three two-cue learning tasks, one with two direct relationships, one with a combination of direct and inverse relationships, and one with two inverse relationships (the Multiple-Cue Probability Learning paradigm). Four groups of participants were included in the study: young adults (18- to 25-year-olds), adults (40- to 50-year-olds), elderly people (65- to 74-year-olds), and very elderly people (75- to 90-year-olds). It was shown that (a) older adults are able to reject the direct relationship "default" hypothesis and select the inverse relationship hypothesis when outcome feedback contradicting the default hypothesis is given, and provided that the learning setting be a very simple one, involving only one cue; (b) some older adults are able to select the inverse relationship hypothesis provided that the learning setting be a simple one,involving only two inverse relationship cues; and (c) very few older adults are able to select the inverse relationship hypothesis when the learning setting is a complex one, involving two cues with both direct and inverse relationships with the criterion. These results led to the revision of the "gradual decrease of cognitive flexibility in older adults" hypothesis proposed by Chasseigne, Mullet, and Stewart (Acta Psychologicgrave;a, 103, 229-238, 1997). 相似文献
952.
Lemaire SD Guillon B Le Maréchal P Keryer E Miginiac-Maslow M Decottignies P 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(19):7475-7480
Proteomics were used to identify the proteins from the eukaryotic unicellular green alga Chlamydomonas reinhardtii that can be reduced by thioredoxin. These proteins were retained specifically on a thioredoxin affinity column made of a monocysteinic thioredoxin mutant able to form mixed disulfides with its targets. Of a total of 55 identified targets, 29 had been found previously in higher plants or Synechocystis, but 26 were new targets. Biochemical tests were performed on three of them, showing a thioredoxin-dependent activation of isocitrate lyase and isopropylmalate dehydrogenase and a thioredoxin-dependent deactivation of catalase that is redox insensitive in Arabidopsis. In addition, we identified a Ran protein, a previously uncharacterized nuclear target in a photosynthetic organism. The metabolic and evolutionary implications of these findings are discussed. 相似文献
953.
Mesenchymal stem cells exert differential effects on alloantigen and virus-specific T-cell responses 总被引:2,自引:0,他引:2
Karlsson H Samarasinghe S Ball LM Sundberg B Lankester AC Dazzi F Uzunel M Rao K Veys P Le Blanc K Ringdén O Amrolia PJ 《Blood》2008,112(3):532-541
Mesenchymal stem cells (MSCs) suppress alloantigen-induced T-cell functions in vitro and infusion of third-party MSCs seems to be a promising therapy for graft-versus-host disease (GVHD). Little is known about the specificity of immunosuppression by MSCs, in particular the effect on immunity to pathogens. We have studied how MSCs affect T-cell responses specific to Epstein-Barr virus (EBV) and cytomegalovirus (CMV). We found that EBV- and CMV-induced proliferation and interferon- (IFN-) production from peripheral blood mononuclear cells (PBMCs) was less affected by third-party MSCs than the response to alloantigen and that MSCs had no effect on expansion of EBV and CMV pentamer-specific T cells. Established EBV-specific cytotoxic T cells (CTL) or CMV-CTL cultured with MSCs retained the ability to proliferate and produce IFN- in response to their cognate antigen and to kill virally infected targets. Finally, PBMCs from 2 patients who received MSCs for acute GVHD showed persistence of CMV-specific T cells and retained IFN- response to CMV after MSC infusion. In summary, MSCs have little effect on T-cell responses to EBV and CMV, which contrasts to their strong immunosuppressive effects on alloreactive T cells. These data have major implications for immunotherapy of GVHD with MSCs and suggest that the effector functions of virus-specific T cells may be retained after MSC infusion. 相似文献
954.
许乐 《中华消化内镜杂志》2005,26(1):281-282
胃肠镜检查时易引起恶心、呕吐、腹痛,使患者产生畏惧心理,而对伴有心肺脑血管疾病的老年患者,还可引起心律失常或心肌梗死.合理的麻醉能消除患者的恐惧心理,抑制恶心、呕吐、疼痛反应,从而稳定呼吸循环功能,预防相关并发症的发生,但老年患者对麻醉药物耐受性差,且多伴有心肺脑血管疾病,故麻醉胃肠镜检查存在一定风险. 相似文献
955.
Barbara M Murphy Peter C Elliott Rosemary O Higgins Michael R Le Grande Marian U C Worcester Alan J Goble James Tatoulis 《European journal of cardiovascular prevention and rehabilitation》2008,15(4):434-440
BACKGROUND: To target interventions, patients at risk for poor outcomes after a cardiac event need to be identified. We investigated trajectories of anxiety and depression after coronary artery bypass graft surgery (CABGS) and identified patients at risk of persistent or worsening anxiety and depression. METHODS: A consecutive sample of 184 patients on the waiting list for CABGS at The Royal Melbourne Hospital completed self-report questionnaires before surgery, and at 2 and 6 months postsurgery. Anxiety and depression were measured using the Hospital Anxiety and Depression Scale. Growth mixture modelling identified trajectories of anxiety and depression. RESULTS: Two possible trajectories emerged for anxiety, whereas three trajectories emerged for depression. Most patients (92%) followed a trajectory of minor presurgical anxiety that remitted in 6 months after CABGS, with the remainder (8%) following a trajectory of major anxiety that remitted in the same period. Minor remitted depression was also common (72% patients). Two less common depression trajectories indicated worsening or unresolved depression. One trajectory began with major presurgical depression that partially remitted by 6 months (14% patients) and the other began with minor presurgical depression that worsened by 6 months (14% patients). Unpartnered patients, smokers, those with presurgical anxiety, high cholesterol, angina, more severe disease or having repeat CABGS were at increased risk for a poor depression trajectory. CONCLUSION: Although initial anxiety and depression resolved or lessened for most patients, some patients experienced persistent or worsening depression after CABGS. Interventions can be targeted toward 'at risk' patients. 相似文献
956.
Thomas X Elhamri M Chelghoum Y Reman O Arnaud P Raffoux E Le QH Tavernier E Dombret H Michallet M 《Annals of hematology》2005,84(6):376-382
Following a dose-escalation study performed to assess the maximally tolerated dose of high-dose mitoxantrone in a single injection combined with chemotherapy, a phase II trial (EMA 2000 regimen) was performed in patients with refractory or relapsed acute myelogenous leukemia (AML) between October 2000 and December 2003. Sixty-two patients entered the study and received mitoxantrone 45 mg/m2 on day 1 in combination with cytarabine and etoposide. Overall, 39 patients (63%) achieved complete remission (CR). Four patients died during remission induction, and 19 patients had resistant disease. Median time to granulocyte and platelet recovery was 34 and 39 days, respectively. The predominant non-hematologic toxicity was infection, with 53% severe infections. Thirty-three of the 39 remitters received subsequent treatment consisting of maintenance chemotherapy courses in 17 patients, allogeneic stem cell transplantation (SCT) in 7 patients, and autologous SCT in 9 patients. The median overall survival of the entire cohort was 8.1 months, with 18% at 2.5 years. EMA chemotherapy using a single injection of mitoxantrone is effective in the treatment of high-risk AML. CR proportion was significantly higher in patients with a first CR duration 6 months when compared with those from a control trial using standard-dose mitoxantrone (90 vs 70%, p=0.03). 相似文献
957.
958.
P E Duffy H Le Guillouzic R F Gass B L Innis 《The American journal of tropical medicine and hygiene》1990,43(5):520-526
Scrub and murine typhus have been identified as causes of illness among the 238,000 displaced Khmer people residing in temporary settlements on the Thai side of the Thai-Cambodian border. Still, the true extent of the problem and the relative frequency of infection with scrub typhus as compared to murine typhus are unknown. We evaluated consecutive patients with unexplained pyrexia (documented fever, no exclusionary diagnosis, and constitutional symptoms) in 1 temporary settlement over 1 month. Laboratory studies included culture of blood and assay of paired sera for rickettsial IgM and IgG antibody, for dengue IgM and IgG antibody, and for leptospiral IgM and IgG antibody. Among 37 patients (27 adults and 10 children), 28 (75%) had a rickettsiosis (26 cases of murine typhus and 2 cases of scrub typhus). No case of enteric fever, dengue, or leptospirosis was diagnosed. The illnesses of 9 patients were not identified. Signs and symptoms did not distinguish confirmed rickettsial infections from undiagnosed illnesses. The 1 month attack rate of rickettsial infection was 29/100,000 for children and 185/100,000 for adults. Murine typhus was a major cause of febrile illness in this settlement. 相似文献
959.
P Penther J Boschat Y Etienne J Le Potier 《Annales de cardiologie et d'angeiologie》1988,37(7):361-363
The association: anterior infarction of the left ventricle-posterior infarction of the right ventricle, is a rare entity. The authors report the case of a 64 year-old woman, who died on the fifth day of an extended anterior myocardial infarction, present on electrocardiograms; there were however immediate signs of right heart failure unexplained by a pericardial effusion. At the autopsy, the unusual length and distribution of the anterior interventricular artery which was completely obstructed near its origin by a thrombosis occurring on a severe atheromatous and calcified stenosis, explain this association. 相似文献
960.
Erythroblasts secrete the nonclassical HLA-G molecule from primitive to definitive hematopoiesis 总被引:7,自引:0,他引:7
Menier C Rabreau M Challier JC Le Discorde M Carosella ED Rouas-Freiss N 《Blood》2004,104(10):3153-3160