全文获取类型
收费全文 | 5306篇 |
免费 | 368篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 90篇 |
妇产科学 | 73篇 |
基础医学 | 776篇 |
口腔科学 | 240篇 |
临床医学 | 417篇 |
内科学 | 1153篇 |
皮肤病学 | 70篇 |
神经病学 | 624篇 |
特种医学 | 149篇 |
外科学 | 986篇 |
综合类 | 35篇 |
一般理论 | 3篇 |
预防医学 | 249篇 |
眼科学 | 87篇 |
药学 | 337篇 |
中国医学 | 4篇 |
肿瘤学 | 368篇 |
出版年
2023年 | 37篇 |
2022年 | 68篇 |
2021年 | 153篇 |
2020年 | 94篇 |
2019年 | 131篇 |
2018年 | 169篇 |
2017年 | 135篇 |
2016年 | 135篇 |
2015年 | 147篇 |
2014年 | 243篇 |
2013年 | 241篇 |
2012年 | 426篇 |
2011年 | 446篇 |
2010年 | 224篇 |
2009年 | 213篇 |
2008年 | 374篇 |
2007年 | 341篇 |
2006年 | 308篇 |
2005年 | 303篇 |
2004年 | 235篇 |
2003年 | 240篇 |
2002年 | 224篇 |
2001年 | 47篇 |
2000年 | 30篇 |
1999年 | 45篇 |
1998年 | 67篇 |
1997年 | 36篇 |
1996年 | 38篇 |
1995年 | 36篇 |
1994年 | 30篇 |
1993年 | 26篇 |
1992年 | 28篇 |
1991年 | 39篇 |
1990年 | 27篇 |
1989年 | 31篇 |
1988年 | 30篇 |
1987年 | 26篇 |
1986年 | 32篇 |
1985年 | 43篇 |
1984年 | 27篇 |
1983年 | 24篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 21篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1975年 | 6篇 |
1974年 | 9篇 |
1973年 | 13篇 |
1967年 | 8篇 |
排序方式: 共有5698条查询结果,搜索用时 15 毫秒
1.
Madan M. Rehani Emily R. Melick Raza M. Alvi Ruhani Doda Khera Salma Batool-Anwar Tomas G. Neilan Michael Bettmann 《European radiology》2020,30(4):1839-1846
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria. 相似文献
2.
3.
Sergue? O Fetissov Jarmila Hallman Ida Nilsson Ann-Kari Lefvert Lars Oreland Tomas H?kfelt 《Neuropsychopharmacology》2006,60(8):799-802
BACKGROUND: Altered stress response is characteristic for subjects with abnormal aggressive and antisocial behavior, but the underlying biological mechanisms are unclear. We hypothesized that autoantibodies (autoAbs) directed against several stress-related neurohormones may exist in aggressive subjects. METHODS: Using enzyme-linked immunosorbent assay, we studied whether autoAbs directed against corticotropin (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), oxytocin, and vasopressin are present in serum of male subjects with conduct disorder and prisoners with history of violence. Healthy blood donors served as control subjects. RESULTS: Both conduct disorder and prisoners groups displayed strongly increased levels of ACTH-reactive immunoglobulin G (IgG) and immunoglobulin M (IgM) autoAbs compared with control subjects. Levels of oxytocin-reactive IgM autoAbs were slightly increased in both groups of aggressive subjects, whereas levels of vasopressin-reactive IgG and IgM autoAbs were lower only in conduct disorder. No differences in the levels of alpha-MSH-reactive autoAbs were found between aggressive and control subjects. CONCLUSIONS: High levels of ACTH-reactive autoAbs as well as altered levels of oxytocin- and vasopressin-reactive autoAbs found in aggressive subjects may interfere with the neuroendocrine mechanisms of stress and motivated behavior. Our data suggest a new biological mechanism of human aggressive behavior that involves autoAbs directed against several stress-related neurohormones. 相似文献
4.
5.
We would like to thank Professor Erdem Kasikcioglu for his interestin our article. In response to the initial question of why exhaustivephysical activity suppresses diastolic function, 相似文献
6.
Hospital outbreak caused by a carbapenem-resistant strain of Acinetobacter baumannii: patient prognosis and risk-factors for colonisation and infection 总被引:10,自引:0,他引:10
M. del Mar Tomas M. Cartelle S. Pertega A. Beceiro P. Llinares D. Canle F. Molina R. Villanueva J. M. Cisneros G. Bou 《Clinical microbiology and infection》2005,11(7):540-546
Between October 2001 and August 2002, 30 hospital patients became infected or colonised by a multiresistant (including to carbapenems) epidemic strain of Acinetobacter baumannii (AbMR) in a hospital outbreak. This study analysed the risk-factors associated with acquisition of this epidemic strain and investigated the prognosis of patients infected by AbMR, with the aim of elucidating factors which lead to mortality. A case-control study of the acquisition of AbMR in patients infected or colonised in the hospital outbreak was performed. Independent risk-factors leading to death were studied by logistic regression analysis. Multivariate analysis of the risk-factors for colonisation/infection with AbMR revealed an independent association with the presence of an arterial catheter (OR, 1.13; 95% CI, 1.03-1.25) and administration of imipenem as monotherapy (OR, 11.12; 95% CI, 2.33-53.09). Multivariate analysis of the prognostic features leading to mortality revealed a significant association with hypotension or shock (OR, 24.63; 95% CI, 1.56-387.56) at the time of bacterial isolation. 相似文献
7.
D Lundgren H Rylander M Andersson C Johansson T Albrektsson 《Clinical oral implants research》1992,3(3):136-143
The aim of these animal experiments was to characterize and evaluate the healing-in of root analogue titanium implants fitting with high precision to the alveolar wall. Four beagle dogs were used in the study. The roots of the 3rd and 4th mandibular premolars in both quadrants of 3 dogs and in 1 quadrant of 1 dog (dog 4) were extracted after hemisection. Each root was machine-copied to 1 titanium analogue. In dog 4, however, 2 titanium analogues were fabricated from each of the 4 extracted roots. This enabled insertion of analogues also into the contralateral sockets obtained by extraction of the corresponding roots immediately before implant installation, which was undertaken 2 weeks after the first extractions. Thus, in all, 32 analogues were implanted in their respective (or contralateral) sockets following ridge incision and elevation of mucoperiosteal flaps. The analogues were carefully covered by the repositioned flaps. In dog 4, 2 analogues from the immediate sockets and 2 from the 2-week sockets were surgically exposed and supplied with titanium crowns after a healing period of 2 months. The healing after implantation was evaluated by clinical, radiographic and histological measures after 2, 12 or 36 months. Two analogues (6%) were lost due to early (during the 1st week) exposure to the oral cavity. Another 2 analogues (6%) were, although not exposed, encapsulated by soft tissue and were easily removed with a surgical forceps. Twenty-eight analogues (88%) were healed-in by contact between bone and implant (osseointegration).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
9.
The aim of present experimental study, was to investigate whether glow-discharge pretreated screws improved the implant take if initial blood flow was prevented in the implant bed. Glow discharge treatment has in previous studies in soft tissue showed to be advantageous for biological adhesion, presumably due to an increase in surface energy. In bone tissue, so far, positive effects of glow discharge have not been reported. One reason for this could be that circulating blood would immediately contaminate the implant surface and lower the high energy state. To prevent circulating blood to reach the implant bed, we used an infant pneumatic cuff placed on the right leg of the rabbit. The pressure was 300 mm Hg during 2.5 hours. The left leg served as control. After 5 minutes when there were no longer a noticeable pulse, 40 glow-discharged pretreated screws were inserted in the tibia. After 7 weeks the animals were sacrificed. There were no significant differences in torque measurements or histomorphometric analysis between control and test implants. 相似文献
10.
M Gottlander T Albrektsson L V Carlsson 《The International journal of oral & maxillofacial implants》1992,7(4):485-490
Hydroxyapatite-coated and titanium-coated IMZ dental implants were investigated in an animal study. The implants were placed in the distal femurs of rabbits. Six months after placement, histomorphometric evaluation of the bone-to-implant contact was conducted. The hydroxyapatite-coated specimens demonstrated significantly more direct bone contact compared to the titanium-coated controls. 相似文献