全文获取类型
收费全文 | 572篇 |
免费 | 32篇 |
国内免费 | 114篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 26篇 |
妇产科学 | 3篇 |
基础医学 | 44篇 |
口腔科学 | 10篇 |
临床医学 | 138篇 |
内科学 | 143篇 |
皮肤病学 | 23篇 |
神经病学 | 7篇 |
特种医学 | 95篇 |
外科学 | 32篇 |
综合类 | 46篇 |
预防医学 | 29篇 |
眼科学 | 15篇 |
药学 | 78篇 |
中国医学 | 4篇 |
肿瘤学 | 22篇 |
出版年
2021年 | 2篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 18篇 |
2014年 | 16篇 |
2013年 | 40篇 |
2012年 | 17篇 |
2011年 | 19篇 |
2010年 | 26篇 |
2009年 | 35篇 |
2008年 | 6篇 |
2007年 | 74篇 |
2006年 | 29篇 |
2005年 | 18篇 |
2004年 | 8篇 |
2003年 | 4篇 |
2002年 | 9篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 12篇 |
1998年 | 38篇 |
1997年 | 31篇 |
1996年 | 30篇 |
1995年 | 24篇 |
1994年 | 25篇 |
1993年 | 18篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 18篇 |
1988年 | 24篇 |
1987年 | 11篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1958年 | 14篇 |
1955年 | 4篇 |
1951年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有718条查询结果,搜索用时 15 毫秒
61.
J Sigafoos MF O'Reilly S Seely-York J Weru SH Son VA Green 《Disability and rehabilitation》2013,35(21-22):1330-1334
Purpose: To evaluate the acquisition of AAC skills during an initial clinical trial and assess subsequent transfer of the training to the home setting. Method: A 12-year-old male with autism was first seen in a clinical setting to establish the use of a voice-output communication device. After learning to use the device to request access to preferred objects in the clinical trial, the intervention was transferred to the home. Follow-up with the parent was conducted via e-mail and telephone. Videotapes were made of initial home-based sessions to enable evaluation of the participant's progress. Results: The programme was successful in teaching the participant to use a portable AAC device to make requests during the clinical trial and then in two home-based activities. Conclusion: An initial clinical trial with follow-up support for parents may be an efficient method for beginning AAC intervention and transferring the training procedures to the home setting. 相似文献
62.
Acquired immunodeficiency syndrome-associated non-Hodgkin's lymphomas and other malignancies in patients with hemophilia 总被引:3,自引:0,他引:3
Ragni MV; Belle SH; Jaffe RA; Duerstein SL; Bass DC; McMillan CW; Lovrien EW; Aledort LM; Kisker CT; Stabler SP 《Blood》1993,81(7):1889-1897
Non-Hodgkin's lymphoma (NHL) is the most common human immunodeficiency virus (HIV)-associated malignancy in hemophiliacs. We studied the incidence and clinicopathologic features of NHL in 3,041 hemophiliacs followed at 18 US Hemophilia Centers between 1978 and 1989. Of the 1,295 (56.6%) who were HIV(+), 253 (19.5%) developed acquired immunodeficiency syndrome (AIDS), of whom 14 (5.5%) developed NHL. Three NHL occurred in HIV(-) hemophiliacs, for a 36.5-fold greater risk in HIV(+) than HIV(-) hemophiliacs (P < .001). The NHL incidence rate was 29-fold greater than in the US population by Surveillance, Epidemiology, and End Results (SEER) estimates (P < .001). Between 0 and 4 lymphomas have been observed per year between 1978 and 1989. At presentation 13 (92.9%) of the HIV(+) NHL were extranodal. Ten were stage IV, 1 stage II, and 3 stage IE. Ten (71.4%) were high-grade, 3 (21.4%) intermediate-grade, and 1 (7.1%) was a low-grade B-cell lymphoma. Epstein-Barr virus (EBV) DNA was detected in 36% by in situ hybridization, including one central nervous system (CNS) lymphoma. The mean CD4 cell count at NHL diagnosis was 64/mm3, the mean latency from initial HIV infection was estimated to be 59 months, and the median survival was 7 months. The incidence of basal cell carcinoma in HIV(+) hemophiliacs was 18.3-fold greater than in HIV(-) hemophiliacs (P < .001) and 11.4-fold greater than in the US population (P < .001). In conclusion, incidence rates of NHL and basal cell carcinoma in HIV(+) hemophiliacs are significantly increased over rates in HIV(-) hemophiliacs and over rates in the US population. Clinicopathologic presentation of NHL in HIV(+) hemophiliacs is similar to that in HIV(+) homosexual men. 相似文献
63.
Bench-to-bedside review: Diaphragm muscle function in disuse and acute high-dose corticosteroid treatment 下载免费PDF全文
Critically ill patients may require mechanical ventilatory support and short-term high-dose corticosteroid to treat some specific
underlying disease processes. Diaphragm muscle inactivity induced by controlled mechanical ventilation produces dramatic alterations
in diaphragm muscle structure and significant losses in function. Although the exact mechanisms responsible for losses in
diaphragm muscle function are still unknown, recent studies have highlighted the importance of proteolysis and oxidative stress.
In experimental animals, short-term strategies that maintain partial diaphragm muscle neuromechanical activation mitigate
diaphragmatic force loss. In animal models, studies on the influence of combined controlled mechanical ventilation and short-term
high-dose methylprednisolone have given inconsistent results in regard to the effects on diaphragm muscle function. In the
critically ill patient, further research is needed to establish the prevalence and mechanisms of ventilator-induced diaphragm
muscle dysfunction, and the possible interaction between mechanical ventilation and the administration of high-dose corticosteroid.
Until then, in caring for these patients, it is imperative to allow partial activation of the diaphragm, and to administer
the lowest dose of corticosteroid for the shortest duration possible. 相似文献
64.
美托洛尔治疗右室流出道室性早搏的效果观察 总被引:1,自引:0,他引:1
目的:观察美托洛尔对起源于右室流出道室性早搏的疗效。方法:选择起源于右室流出道的室性早搏患25例,给予美托洛尔治疗,剂量从6.25mg开始,无不良反应后,逐渐加量,最大剂量每天100-150mg,疗程3个月,用药前后查12导联体表心电图、24小时动态心电图及结合临床症状进行评定。结果:①临床症状评定:胸闷心悸25例,治疗后减轻20例,有效率为80%;焦虑20例,治疗后症状均消失,有效率为100%;头晕14例,治疗后减轻12例,有效率为85.7%。②室性早搏评定:25例中达到室性早搏抑制率70%有11例,有效率为44%;平均室性早搏抑制率为45.6%,6例成对室性早搏抑制率为80%,3例短阵室速消失,平均心率降低12.6/min。③生化指标:血糖、胆固醇、甘油、三酯治疗前后无明显改变。④2例因血压低未加药量。结论:美托洛尔治疗起源于右室流出道室性早搏疗效肯定,尤其对运动后早搏增多疗效较好,临床太改善较显,观察中未发现明显不良反应,无致心律失常现象。 相似文献
65.
66.
L.A. BOCKERIA A. SH. REVISHVILY I.P. POLJAKOVA 《Pacing and clinical electrophysiology : PACE》1990,13(9):1110-1115
A method of ECG mapping from 90 points on the chest surface is described in 41 male and 17 female patients, aged 6 to 59 years. All also underwent invasive electrophysiological investigation and intraoperative epicardial mapping. Fifty-two patients had one, three patients two, and one patient had three anomalous accessory pathways. Two patients had nodoventricular tracts (Mahaim fibers). We distinguished seven zones along the atrioventricular groove (AVG) to compare the data derived from epicardial, endocardial, and body surface mapping. A microcomputer was used for the analysis of all ECGs to construct and analyze the isopotential maps. The criterion for localization of the anomalous accessory pathways was determined after analysis of the data from all 58 patients. The localization criterion was the appearance of a minimal deflection (-0.09 +/- 0.03 mV) on the surface isopotential maps within the first 0.28 msec of the QRS complex. This criterion for localization of anomalous accessory pathways from the chest surface was proposed on the basis of comparison of data from selective coronary angiography, the ventriculogram, and the chest X ray i.e., radiographic-topographic-anatomical data. In 20 patients, 10-20 nontraditional ECG leads were recorded from the chest to reflect the atrioventricular groove. The number of nontraditional ECG leads depended on patient age, weight, and height. Localization of the accessory pathway in one of the seven zones was established by the earliest delta wave and its maximum deviation. It was possible to localize the anomalous accessory pathway and to suspect multiple pathways in 95% of cases using nontraditional ECG leads and the listed criteria.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
67.
Pregnancy augments nitric oxide-dependent dilator response to acetylcholine in the human uterine artery 总被引:4,自引:1,他引:3
Nelson SH; Steinsland OS; Suresh MS; Lee NM 《Human reproduction (Oxford, England)》1998,13(5):1361-1367
The influence of pregnancy on the dilator effects of acetylcholine in the
isolated human uterine artery was investigated. Acetylcholine (0.1 nM to
0.1 microM) produced concentration- and endothelium-dependent relaxation of
norepinephrine (3 microM)-induced contraction. The relaxation was greater
in arteries from pregnant patients (P arteries) than from non-pregnant
patients (NP arteries). The maximal relaxation was 53.5+/-3.4% (n=21) in P
arteries and 23.5+/-2.5% (n=35) in NP arteries. In both P and NP arteries
the cholinergic relaxation was increased in the presence of superoxide
dismutase and greatly reduced in the presence of the nitric oxide synthase
inhibitors, NG-mono-methyl L-arginine (L-NMMA) and
L-nitro-arginine-methylester (L-NAME). The effect of these nitric oxide
synthase inhibitors was reversed by L- arginine. We conclude that pregnancy
enhances acetylcholine-induced nitric oxide synthesis and release in the
human uterine artery.
相似文献
68.
69.
70.
SH Opdal TO Rognum Å Vege AK Stave BM Dupuy T Egeland 《Acta paediatrica (Oslo, Norway : 1992)》1998,87(10):1039-1044
The purpose of the present study was to investigate substitutions in the D-loop of mitochondrial DNA (mtDNA) in sudden infant death syndrome (SIDS) and controls, since several observations indicate the involvement of mtDNA mutations in SIDS. These include elevated levels of vitreous humour hypoxanthine in SIDS victims, familial clustering without mendelian traits, and observations of increased sleepiness and a lower activity score in infants who later succumbed to SIDS. Eighty-two cases of SIDS and 133 controls were investigated and the D-loop sequences were recorded in the base-pair range 16 055-16 500 in the mtDNA sequence. The sequencing was carried out using the Applied Biosystems Sequenase dye terminator method and a ABD373A sequencer. The recorded D-loop sequences were compared with the Cambridge sequence and differences were recorded as substitutions. The SIDS cases had a tendency towards a higher substitution rate in the D-loop than the controls ( p = 0.088). This observation makes it interesting to search for deleterious mutations in other locations in the mtDNA. 相似文献