全文获取类型
收费全文 | 5243篇 |
免费 | 357篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 116篇 |
妇产科学 | 65篇 |
基础医学 | 773篇 |
口腔科学 | 47篇 |
临床医学 | 536篇 |
内科学 | 1319篇 |
皮肤病学 | 46篇 |
神经病学 | 476篇 |
特种医学 | 341篇 |
外科学 | 837篇 |
综合类 | 16篇 |
一般理论 | 6篇 |
预防医学 | 279篇 |
眼科学 | 40篇 |
药学 | 336篇 |
中国医学 | 2篇 |
肿瘤学 | 348篇 |
出版年
2023年 | 41篇 |
2022年 | 67篇 |
2021年 | 220篇 |
2020年 | 101篇 |
2019年 | 161篇 |
2018年 | 202篇 |
2017年 | 135篇 |
2016年 | 148篇 |
2015年 | 163篇 |
2014年 | 232篇 |
2013年 | 290篇 |
2012年 | 423篇 |
2011年 | 431篇 |
2010年 | 221篇 |
2009年 | 203篇 |
2008年 | 296篇 |
2007年 | 304篇 |
2006年 | 233篇 |
2005年 | 221篇 |
2004年 | 158篇 |
2003年 | 169篇 |
2002年 | 127篇 |
2001年 | 77篇 |
2000年 | 69篇 |
1999年 | 63篇 |
1998年 | 42篇 |
1997年 | 36篇 |
1996年 | 41篇 |
1995年 | 44篇 |
1994年 | 28篇 |
1993年 | 27篇 |
1992年 | 56篇 |
1991年 | 42篇 |
1990年 | 67篇 |
1989年 | 62篇 |
1988年 | 50篇 |
1987年 | 45篇 |
1986年 | 34篇 |
1985年 | 38篇 |
1984年 | 22篇 |
1983年 | 25篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 13篇 |
1979年 | 22篇 |
1978年 | 17篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1975年 | 15篇 |
1967年 | 12篇 |
排序方式: 共有5632条查询结果,搜索用时 859 毫秒
71.
Carrie Anna McGinn Sonya Grenier Julie Duplantie Nicola Shaw Claude Sicotte Luc Mathieu Yvan Leduc France Légaré Marie-Pierre Gagnon 《BMC medicine》2011,9(1):46
Background
Electronic health record (EHR) implementation is currently underway in Canada, as in many other countries. These ambitious projects involve many stakeholders with unique perceptions of the implementation process. EHR users have an important role to play as they must integrate the EHR system into their work environments and use it in their everyday activities. Users hold valuable, first-hand knowledge of what can limit or contribute to the success of EHR implementation projects. A comprehensive synthesis of EHR users' perceptions is key to successful future implementation. This systematic literature review was aimed to synthesize current knowledge of the barriers and facilitators influencing shared EHR implementation among its various users. 相似文献72.
Peggy Papeleu Tamara Vanhaecke Greetje Elaut Mathieu Vinken Tom Henkens Sarah Snykers 《Critical reviews in toxicology》2013,43(4):363-378
Histone deacetylase (HDAC) inhibitors target key steps of tumor development: They inhibit proliferation, induce differentiation and/or apoptosis, and exhibit potent antimetastatic and antiangiogenic properties in transformed cells in vitro and in vivo. Preliminary studies in animal models have revealed a relatively high tumor selectivity of HDAC inhibitors, strenghtening their promising potential in cancer chemotherapy. Until now, preclinical in vitro research has almost exclusively been performed in cancer cell lines and oncogene-transformed cells. However, as cell proliferation and apoptosis are essential for normal tissue and organ homeostasis, it is important to investigate how HDAC inhibitors influence the regulation of and interplay between proliferation, differentiation, and apoptosis in primary cells as well. This review highlights the discrepancies in molecular events triggered by trichostatin A, the reference compound of hydroxamic acid-containing HDAC inhibitors, in hepatoma cells and primary hepatocytes (which are key targets for drug-induced toxicity). The implications of these differential outcomes in both cell types are discussed with respect to both toxicology and drug development. In view of the future use of HDAC inhibitors as cytostatic drugs, it is highly recommended to include both tumor cells and their healthy counterparts in preclinical developmental studies. Screening the toxicological properties of compounds early in their development process, using a battery of different cell types, will enable researchers to discard those compounds bearing undesirable adverse activity before entering into expensive clinical trials. This will not only reduce the risk for harmful exposure of patients but also save time and money. 相似文献
73.
Cultures of primary hepatocytes are versatile tools that can serve many in vitro toxicity testing purposes. However, they cope with dedifferentiation, a process that is already initiated during the hepatocyte isolation procedure and that is manifested as the progressive loss of functionality upon subsequent cultivation. A number of strategies to prevent dedifferentiation have been introduced over the last decades, all which aim at re-establishing the in vivo hepatocyte micro-environment in vitro, but that are of merely limited success. Recent mechanistic insight into the mechanisms that underlie hepatocyte dedifferentiation has opened new avenues for the development of novel approaches that target the actual causes of this deteriorative process and thus for the generation of a long-term hepatic in vitro tool. Such experimental system is urgently needed, especially in the light of the stringent European legislative modifications that are currently encountered by the pharmaceutical, chemical and, particularly, the cosmetic industry. 相似文献
74.
75.
76.
Eva Compérat Stéphane Larré Morgan Roupret Yann Neuzillet Géraldine Pignot Hervé Quintens Nadine Houéde Catherine Roy Xavier Durand Justine Varinot Dimitri Vordos Mathieu Rouanne Mohammed Adnan Bakhri Priscilla Bertrand Stephane Calin Jeglinschi Olivier Cussenot Michel Soulié Christian Pfister 《Virchows Archiv : an international journal of pathology》2015,466(5):589-594
77.
Mathieu Van der Aerschot Faheema Mahomed-Asmail Herman Carel Myburgh Robert Henry Eikelboom 《International journal of audiology》2016,55(11):616-622
Objective: Evaluation of the Sennheiser HD 202 II supra-aural headphones as an alternative headphone to enable more affordable hearing screening. Design: Study 1 measured the equivalent threshold sound pressure levels (ETSPL) of the Sennheiser HD 202 II. Study 2 evaluated the attenuation of the headphones. Study 3 determined headphone characteristics by analyzing the total harmonic distortion (THD), frequency response and force of the headband. Study sample: Twenty-five participants were included in study 1 and 15 in study 2 with ages ranging between 18 and 25. No participants were involved in study 3. Results: The Sennheiser HD 202 II ETSPLs (250–16000?Hz) showed no significant effects on ETSPL for ear laterality, gender or age. Attenuation was not significantly different (p?>?0.01) to TDH 39 except at 8000?Hz (p?0.01). Maximum permissible ambient noise levels (MPANL) were specified accordingly. The force of the headband was 3.1N. THD measurements showed that between 500 and 8000?Hz intensities of 90?dB HL and higher can be reached without THD?>3%. Conclusion: Sennheiser HD 202 II supra-aural headphones can be used as an affordable headphone for screening audiometry provided reported MPANLs, maximum intensities and ETSPL values are employed. 相似文献
78.
Gerbaud E Harcaut E Coste P Erickson M Lederlin M Labèque JN Perron JM Cochet H Dos Santos P Durrieu-Jaïs C Laurent F Montaudon M 《The international journal of cardiovascular imaging》2012,28(4):783-794
To evaluate the incremental diagnostic and prognostic value of cardiac magnetic resonance (CMR) in patients with chest pain, raised troponin and unobstructed coronary arteries, and to compare subsequent event rates between diagnostic groups. 130 patients (mean age: 54?±?17) presenting with troponin-positive acute chest pain and unobstructed coronary arteries were included. All patients were managed according to European Society of Cardiology guidelines, including echocardiography, and had CMR within 6.2?±?5.3?days of presentation. During follow-up, major adverse cardiovascular events (MACE) were recorded. CMR provided a diagnosis in 100 of 130 patients (76.9%), with the remaining 30 (23.1%) having a normal examination. CMR diagnosed 37 (28.5%) acute myocardial infarctions, 34 (26.1%) myocarditis, 28 (21.5%) apical ballooning syndromes and 1 (0.8%) hypertrophic cardiomyopathy. When a single diagnosis was suspected by the referring physician, CMR validated this diagnosis in 32 patients (76.2%). CMR provided a formal diagnosis in 61 patients (69.3%) in which the clinical diagnosis was uncertain between at least two possibilities. CMR corrected a wrong diagnosis in 10 patients (7.7%). CMR-suggested diagnosis led to a modification of therapy in 42 patients (32.3%). Median follow-up was 34?months (interquartile range 24–49) in 124 patients. Sixteen patients (12.9%) experienced MACE. MACE rate was not different between patients with a conclusive CMR and normal CMR. In patients with acute troponin-positive chest pain and unobstructed coronary arteries, early CMR has important diagnostic and therapeutic implications. However its association with occurrence of MACE during mid term follow-up was not obvious. 相似文献
79.