全文获取类型
收费全文 | 5549篇 |
免费 | 662篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 79篇 |
儿科学 | 186篇 |
妇产科学 | 154篇 |
基础医学 | 803篇 |
口腔科学 | 82篇 |
临床医学 | 635篇 |
内科学 | 1212篇 |
皮肤病学 | 128篇 |
神经病学 | 544篇 |
特种医学 | 298篇 |
外科学 | 671篇 |
综合类 | 167篇 |
现状与发展 | 30篇 |
一般理论 | 4篇 |
预防医学 | 583篇 |
眼科学 | 51篇 |
药学 | 284篇 |
中国医学 | 5篇 |
肿瘤学 | 320篇 |
出版年
2023年 | 196篇 |
2022年 | 45篇 |
2021年 | 73篇 |
2020年 | 94篇 |
2019年 | 69篇 |
2018年 | 112篇 |
2017年 | 88篇 |
2016年 | 95篇 |
2015年 | 117篇 |
2014年 | 175篇 |
2013年 | 178篇 |
2012年 | 211篇 |
2011年 | 235篇 |
2010年 | 194篇 |
2009年 | 189篇 |
2008年 | 191篇 |
2007年 | 248篇 |
2006年 | 207篇 |
2005年 | 188篇 |
2004年 | 202篇 |
2003年 | 207篇 |
2002年 | 203篇 |
2001年 | 154篇 |
2000年 | 159篇 |
1999年 | 183篇 |
1998年 | 98篇 |
1997年 | 98篇 |
1996年 | 100篇 |
1995年 | 80篇 |
1994年 | 78篇 |
1993年 | 68篇 |
1992年 | 132篇 |
1991年 | 119篇 |
1990年 | 129篇 |
1989年 | 134篇 |
1988年 | 120篇 |
1987年 | 93篇 |
1986年 | 81篇 |
1985年 | 83篇 |
1984年 | 73篇 |
1983年 | 57篇 |
1982年 | 58篇 |
1981年 | 36篇 |
1980年 | 46篇 |
1979年 | 42篇 |
1978年 | 39篇 |
1977年 | 39篇 |
1976年 | 53篇 |
1975年 | 37篇 |
1974年 | 37篇 |
排序方式: 共有6236条查询结果,搜索用时 15 毫秒
1.
A mixed‐method study of effects of a therapeutic play intervention for children on parental anxiety and parents' perceptions of the intervention 下载免费PDF全文
2.
3.
4.
5.
Rapid desensitization of the acute stimulatory effects of nicotine on rat plasma adrenocorticotropin and prolactin 总被引:5,自引:0,他引:5
The dose of nicotine and the frequency of its administration appear to be essential determinants of its action on multiple systems including the neuroendocrine regulation of the adrenocorticotropin (ACTH)-corticosterone and prolactin (PRL) axes in the rat. Because desensitization to the acute depressive effects of nicotine has been observed after both acute and chronic administration, these investigations assessed whether desensitization to the stimulative effects of nicotine on ACTH and PRL secretion occurs with repetitive dosing. Extensive dose and time course experiments showed that nicotine rapidly elevates rat plasma ACTH and PRL levels with a threshold dose between 0.1 to 0.25 mg/kg b.wt. i.p. After the stimulation of PRL, levels became significantly depressed. Desensitization to the acute stimulatory effects of nicotine on both hormones was induced by a single dose of nicotine (0.5 mg/kg). One hour later nicotine (1.0 mg/kg) failed to significantly stimulate PRL levels and resulted in a modest increase of ACTH. Desensitization was maximal by 1 hr after the first dose and persisted for at least 6 hr. Adrenalectomy, performed to eliminate corticosterone-induced negative feedback, did not enhance PRL responsiveness to a second dose of nicotine but it partially restored the ACTH response. Pretreatment with corticosterone also failed to modify the PRL response to a single dose of nicotine whereas it partially suppressed the ACTH response. Rapid desensitization to the acute stimulatory effects of nicotine on plasma PRL is independent of glucocorticoid negative-feedback whereas desensitization of the ACTH response is modestly dependent. 相似文献
6.
Effects of eight weeks of bicycle ergometer sprint training on human muscle buffer capacity 总被引:7,自引:0,他引:7
This investigation was undertaken to determine whether human skeletal muscle buffer capacity (BCm) is affected by training. Eight untrained males participated in 8 weeks of sprint training on bicycle ergometers. Muscle biopsy samples were taken from the vastus lateralis before and at several times following an incremental bicycle ergometer test (0 min, 5 min, 15 min). These subjects were tested before (PRE) and following (POST) the training period. Seven endurance-trained cyclists (ET) were also tested for the purpose of comparing the BCm of ET to that of PRE and POST. Biopsy samples were quick-frozen in liquid nitrogen and later analyzed for lactate concentration (HLam), homogenate pH (pHm), and creatine phosphate concentration. BCm was calculated from the change in HLam and pHm observed from rest to exhaustion and was expressed as mmol X kg-1 X pH-1 (Slykes). There was no significant difference in resting HLam or resting pHm among the groups. There was a significant difference in HLam at exhaustion between PRE (21.41 +/- 1.65 mmol X kg-1), POST (25.61 +/- 2.38 mmol X kg-1), and ET (11.16 +/- 0.31 mmol X kg-1) but no significant difference in pHm at exhaustion between PRE (6.65 +/- 0.03 pH units) and POST (6.69 +/- 0.06 pH units). pHm at exhaustion for the ET group was significantly higher than the others at 6.91 +/- 0.02 pH units. A significant difference between PRE and POST BCm was found (PRE: 44.68 +/- 3.03 S1; POST: 61.04 +/- 4.11 S1) while ET BCm (47.21 +/- 7.26 S1) was not significantly different from PRE. These data indicate that muscle buffer capacity is increased with highly intense sprint training but provide no evidence to suggest that muscle buffer capacity is affected by endurance training. 相似文献
7.
A metropolitan experience with infrainguinal revascularization. Operative risk and late results in northeastern Ohio 总被引:1,自引:0,他引:1
T D Rafferty J C Avellone C J Farrell N R Hertzer F R Plecha R S Rhodes W V Sharp J M Rogers 《Journal of vascular surgery》1987,6(4):365-371
Despite being of fundamental importance, the late results of major arterial reconstruction rarely have been documented throughout a large metropolitan area. In this study of 932 patients entered into the computer registry of the Cleveland Vascular Society, 19 surgeons representing 13 community hospitals and referral centers in Cleveland and Akron report the intermediate-term outcome during a mean interval of 35 months after infrainguinal lower extremity revascularization performed in northeastern Ohio from 1978 through 1982. Operative risk (5%), the early amputation rate (7%), and actuarial 5-year survival (48% to 55%) for patients with rest pain or tissue necrosis were significantly worse (p less than 0.05) than comparable figures (0.6%, 0%, and 77%, respectively) for others who underwent procedures for disabling claudication. Although both materials had similar success above the knee, the cumulative 3-year patency rate of autogenous vein bypass to the distal popliteal (69% to 88%; p less than 0.05) and tibioperoneal arteries (43%; 0.05 less than p less than 0.1) was superior to the results of polytetrafluoroethylene grafts (32% to 50% and 19%, respectively). Moreover, polytetrafluoroethylene grafts required reoperations at three times the rate of vein grafts to maintain limb salvage. 相似文献
8.
9.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence. 相似文献
10.
The National Health Service Breast Screening Programme was instituted in 1988 following the recommendations of the Forrest report in 1986. From the beginning it has been controversial. Is breast cancer screening efficacious? Can the efficacy produced in trials be reproduced nationwide in the UK? Do the benefits of screening outweigh the adverse effects? Answers to all these questions are not yet available but in the light of current evidence, breast screening does appear to offer a realistic opportunity to reduce the mortality from a disease which constitutes a major public health problem in the UK. The role of the general practitioner and the primary care team is considered in the light of the experience gained in the first phase of the screening programme. 相似文献