全文获取类型
收费全文 | 1932篇 |
免费 | 136篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 74篇 |
妇产科学 | 45篇 |
基础医学 | 242篇 |
口腔科学 | 33篇 |
临床医学 | 252篇 |
内科学 | 419篇 |
皮肤病学 | 27篇 |
神经病学 | 218篇 |
特种医学 | 43篇 |
外科学 | 254篇 |
综合类 | 2篇 |
一般理论 | 1篇 |
预防医学 | 181篇 |
眼科学 | 46篇 |
药学 | 120篇 |
中国医学 | 6篇 |
肿瘤学 | 104篇 |
出版年
2023年 | 11篇 |
2022年 | 23篇 |
2021年 | 40篇 |
2020年 | 35篇 |
2019年 | 64篇 |
2018年 | 58篇 |
2017年 | 56篇 |
2016年 | 58篇 |
2015年 | 44篇 |
2014年 | 65篇 |
2013年 | 110篇 |
2012年 | 119篇 |
2011年 | 140篇 |
2010年 | 64篇 |
2009年 | 72篇 |
2008年 | 112篇 |
2007年 | 114篇 |
2006年 | 115篇 |
2005年 | 98篇 |
2004年 | 81篇 |
2003年 | 82篇 |
2002年 | 59篇 |
2001年 | 30篇 |
2000年 | 22篇 |
1999年 | 20篇 |
1998年 | 20篇 |
1997年 | 21篇 |
1996年 | 25篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 13篇 |
1992年 | 19篇 |
1991年 | 22篇 |
1990年 | 26篇 |
1989年 | 15篇 |
1988年 | 26篇 |
1987年 | 23篇 |
1986年 | 18篇 |
1985年 | 10篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1974年 | 10篇 |
1973年 | 8篇 |
1969年 | 5篇 |
1967年 | 7篇 |
排序方式: 共有2077条查询结果,搜索用时 15 毫秒
11.
Bergmo TS Kummervold PE Gammon D Dahl LB 《International journal of medical informatics》2005,74(9):705-710
BACKGROUND AND AIM: Electronic patient-provider communication promises to improve efficiency and effectiveness of clinical care. This study aims to explore whether a secure web-based messaging system is an effective way of providing patient care in general practices. METHOD: We conducted a randomised controlled trail and recruited 200 patients from the waiting area in one primary clinic in Norway. Participants were randomised to either the intervention group, which received access to a secure messaging system, or the control group receiving standard care without such access. Primary outcome measures were number of online consultations, telephone consultations and office visits in the two groups. Data were derived from patient records and collected 1 year prior to (baseline), and 1 year after the intervention. RESULTS: Forty-six percent of the patients who were given access to the messaging system (n=99) used the online communication system on at least one occasion (ranging from 1 to 17 messages per patient per year). A total of 147 electronic messages were sent to six general practitioners during a 1-year trial period. Eleven percent of the messages were to schedule an appointment. In 10% of the messages, the GP was unable to respond adequately and recommended an office visit. The reduction in office visits over time was greater for the intervention group than for the control group (P=0.034). There was however no significant difference in the number of telephone consultations between the groups during the study (P=0.258). CONCLUSION: The use of a secure electronic messaging system reduced the number of office visits at the general practice, but not phone consultations. 相似文献
12.
Primary antitumor immune response mediated by CD4+ T cells 总被引:7,自引:0,他引:7
Corthay A Skovseth DK Lundin KU Røsjø E Omholt H Hofgaard PO Haraldsen G Bogen B 《Immunity》2005,22(3):371-383
Gene-targeted mice have recently revealed a role for lymphocytes and interferon-gamma (IFNgamma) in conferring protection against cancer, but the mechanisms remain unclear. Here, we have characterized a successful primary antitumor immune response initiated by naive CD4+ T cells. Major histocompatibility complex class II (MHC-II)-negative myeloma cells injected subcutaneously into syngeneic mice were surrounded within 3 days by macrophages that captured tumor antigens. Within 6 days, naive myeloma-specific CD4+ T cells became activated in draining lymph nodes and subsequently migrated to the incipient tumor site. Upon recognition of tumor-derived antigenic peptides presented on MHC-II by macrophages, the myeloma-specific CD4+ T cells were reactivated and started to secrete cytokines. T cell-derived IFNgamma activated macrophages in close proximity to the tumor cells. Tumor cell growth was completely inhibited by such locally activated macrophages. These data indicate a mechanism for immunosurveillance of MHC-II-negative cancer cells by tumor-specific CD4+ T cells through collaboration with macrophages. 相似文献
13.
The behavioural response to intrathecal i.th. serotonin (5-HT) was examined in mice pretreated with the neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) or the 5-HT synthesis inhibitor p-chlorophenylalanine (PCPA) which produce similar extensive depletion of central 5-HT levels. Intrathecal 5-HT (0.4 micrograms) elicited a behavioural response consisting of reciprocal hindlimb scratching and biting or licking of the hindquarters indicative of nociceptive stimulation. The response to i.th. 5-HT was markedly increased 5 days after intracerebroventricular (i.c.v.) injection of 5,7-DHT (80 micrograms base per mouse). On the other hand, 24 h after the last pretreatment injection of PCPA (400 mg kg-1 for 6 consecutive days), the response to i.th. 5-HT was unaltered. These results indicate that i.c.v. 5,7-DHT produces supersensitivity to 5-HT. Since PCPA failed to alter the effect of 5-HT, the supersensitivity seems not to be due to depletion of 5-HT levels after the lesion. 相似文献
14.
The effect of a cold pressor test (CPT) on haemodynamics in relation to general and regional sympathetic activity and arginin vasopressin (AVP), was studied in eleven patients with severe congestive heart failure (CHF). Compared to an age-matched control group (C), resting arterial plasma noradrenaline (NA) (419 +/- 77 vs. 182 +/- 15 pg ml-1), and adrenaline (A) (142 +/- 28 vs 54 +/- 10 pg ml-1) were higher (P less than 0.05) in CHF. AVP showed no significant difference (14 +/- 4 vs. 9 +/- 4 pg ml-1). During CPT systolic and diastolic blood pressure and systemic vascular resistance increased (P less than 0.01), as did NA (delta 114 +/- 39 pg ml-1, P less than 0.01), A (delta 33 +/- 10 pg ml-1, P less than 0.01) and heart rate (delta 10 beats min-1, P less than 0.01). The myocardial v-a difference of NA decreased (P less than 0.05), but was unchanged across the renal vascular bed during CPT. The a-v difference of NA in the hepatic vascular bed, and fractional extraction of A in the coronary sinus, renal and hepatic vascular beds remained unchanged during CPT. AVP did not change significantly and no change in cardiac index or left ventricular filling pressure was observed during CPT. These data suggest that despite an increased activation of the sympathetic nervous system at rest, a further increase in blood pressure and catecholamines took place during CPT. Thus, the effect of a CPT which activates the central sympathetic system seems not to be altered in patients with severe CHF. 相似文献
15.
André Beate Canhão Helena Espnes Geir A. Rodrigues Ana Maria Ferreira Gregorio Maria Joao Nguyen Camilla Sousa Rute Grønning Kjersti 《Zeitschrift fur Gesundheitswissenschaften》2021,29(6):1373-1378
Journal of Public Health - Adolescents’ sleep duration has decreased over the past century; this is mainly caused by problems with falling asleep. Short sleep duration, poor sleep quality,... 相似文献
16.
17.
Geir Bjørklund 《Nutrition and cancer》2013,65(8):1357-1360
Adjuvant Nutritional Intervention in Cancer (ANICA) was a clinical study carried out in Denmark in the 1990s with 32 typical patients with breast cancer, aged 32–81 yr and classified high risk because of tumor spread to the lymph nodes. The patients received standard therapy for their breast cancer, but got from the start additionally an adjuvant therapy in form of a cocktail consisting of vitamin C (2,850 mg/day), vitamin E (2,500 IU/day), beta-carotene (32.5 IU/day), selenium (Se; 387 micrograms/day), various other vitamins and essential trace elements, essential fatty acids (1.2 g gamma-linolenic acid/day and 3.5 g omega-3 PUFAs/day), and coenzyme Q10 (CoQ10, 90 mg/day). The protocol was later changed, with reduction of the Se intake and more coenzyme Q10 than when the study was started. The average survival of high-risk breast patients in the study was 50% after 5 yr, whereas for low-risk breast cancer patients (without metastases in the axilla when treatment was started), the average survival was 90% after ten years. The main investigator died, and the final report from the ANICA study was therefore never written. However, the published preliminary results from the trial were very promising; it seems, therefore, important to follow-up this study. 相似文献
18.
19.
Egil Jellum 《International journal of radiation biology》2013,89(6):577-594
SummaryThe ability of different disulphides to protect solutions of calf-thymus DNA against x-ray-induced damage has been compared. Degradations of the DNA were followed by determining shifts of the Tm value and by determining changes in the ability of DNA to act as primer for the enzymic synthesis of RNA.Diamino-disulphides such as cystamine, which readily interact with DNA, offered significantly better protection of the DNA than diacetyl cystamine and oxidized glutathione. The difference proved to be due, at least in part, to the cystamine-nucleic-acid interaction. These data suggest that diamino-disulphides are efficient protectors of DNA because (a) they contain a disulphide group, (b) they stabilize the DNA-helix, and (c) a substantial amount of the disulphide is localized on the DNA molecule.Radiation-damage of the priming activity of DNA was only partially prevented by the disulphides. No difference in the (weak) protective effect of cystamine and diacetyl cystamine was observed.The possible significance of the cystamine-DNA interaction for radioprotection of DNA in vivo is discussed. 相似文献
20.