全文获取类型
收费全文 | 1715篇 |
免费 | 101篇 |
国内免费 | 113篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 69篇 |
妇产科学 | 14篇 |
基础医学 | 192篇 |
口腔科学 | 25篇 |
临床医学 | 214篇 |
内科学 | 377篇 |
皮肤病学 | 42篇 |
神经病学 | 48篇 |
特种医学 | 405篇 |
外国民族医学 | 1篇 |
外科学 | 85篇 |
综合类 | 47篇 |
预防医学 | 97篇 |
眼科学 | 98篇 |
药学 | 112篇 |
中国医学 | 1篇 |
肿瘤学 | 101篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 25篇 |
2017年 | 10篇 |
2016年 | 29篇 |
2015年 | 31篇 |
2014年 | 26篇 |
2013年 | 52篇 |
2012年 | 34篇 |
2011年 | 49篇 |
2010年 | 59篇 |
2009年 | 60篇 |
2008年 | 48篇 |
2007年 | 85篇 |
2006年 | 42篇 |
2005年 | 73篇 |
2004年 | 21篇 |
2003年 | 34篇 |
2002年 | 22篇 |
2001年 | 32篇 |
2000年 | 42篇 |
1999年 | 36篇 |
1998年 | 99篇 |
1997年 | 101篇 |
1996年 | 107篇 |
1995年 | 70篇 |
1994年 | 70篇 |
1993年 | 72篇 |
1992年 | 21篇 |
1991年 | 36篇 |
1990年 | 30篇 |
1989年 | 59篇 |
1988年 | 45篇 |
1987年 | 60篇 |
1986年 | 37篇 |
1985年 | 50篇 |
1984年 | 23篇 |
1983年 | 21篇 |
1982年 | 27篇 |
1981年 | 22篇 |
1980年 | 33篇 |
1979年 | 9篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 27篇 |
1975年 | 16篇 |
1967年 | 4篇 |
排序方式: 共有1929条查询结果,搜索用时 0 毫秒
1.
R.J.W. de Keizer 《International ophthalmology》1997,21(6):335-341
In a prospective study the results of a pterygium excision in 54 patients (57 eyes) who underwent a superficial free conjunctival
autograft (FCG) were compared to those of patients who were treated with postoperative90Sr-irradiation. In 51 cases the minimum
follow-up was six months, the maximum follow-up seven years. We divided the study up into a randomized part and an open part.
In the randomized part, surgery of a primary pterygium was performed in 25 eyes, of which 16 were treated with a FCG and compared
with 9 eyes with primary pterygium surgery and postoperative90Sr beta-irradiation. In the same period 16eyes were treated
because of a recurrent pterygium: 8 with FCG and 8 with90Sr-irradiation. In the open part of the study16 eyes with primary
pterygium were successively treated with FCG alone.
The results showed in the randomized, as well as in the open study on primary surgery with a minimum follow-up of six month,
one recurrence in each of the FCG-groups (2 out of 31 eyes =6.4%), and no recurrences in the 90Sr-group(0%). In the randomized
group of patients treated for a recurrent pterygium one recurrence developed in the FCG group (1 out of 8 eyes =12.5%) and
one in the 90Sr-group (1 out of 7 =14.6%). Analysis of other clinical parameters showed that postoperative treatment with
corticosteroids, nonsteroidal anti-inflammatory drugs, and artificial tears was necessary for a longer period in the FCG group
than in the90Sr-group.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells. 相似文献
3.
表小檗碱对α受体的作用 总被引:2,自引:0,他引:2
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择 相似文献
4.
5.
6.
Pernes JM; Vitoux JF; Brenoit P; Raynaud A; Parola JL; Roth JP; Angel CY; Fiessinger JN; Roncato M; Gaux JC 《Radiology》1986,158(2):481-485
Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs. 相似文献
7.
Overtraining in elite athletes. Review and directions for the future 总被引:11,自引:0,他引:11
Overtraining is an imbalance between training and recovery. Short term overtraining or 'over-reaching' is reversible within days to weeks. Fatigue accompanied by a number of physical and psychological symptoms in the athlete is an indication of 'staleness' or 'overtraining syndrome'. Staleness is a dysfunction of the neuroendocrine system, localised at hypothalamic level. Staleness may occur when physical and emotional stress exceeds the individual coping capacity. However, the precise mechanism has yet to be established. Clinically the syndrome can be divided into the sympathetic and parasympathetic types, based upon the predominance of sympathetic or parasympathetic activity, respectively. The syndrome and its clinical manifestation can be explained as a stress response. At present, no sensitive and specific tests are available to prevent or diagnose overtraining. The diagnosis is based on the medical history and the clinical presentation. Complete recovery may take weeks to months. 相似文献
8.
9.
R Mokni A Chakar F Bleiberg-Daniel JL Mahu PA Walravens P Chappuis J Navarro D Lemonnier 《Acta paediatrica (Oslo, Norway : 1992)》1993,82(6-7):539-543
Biochemical markers of nutritional status (albumin, transthyretin, insulin-like growth factor-I and zinc) were measured in slowly growing two- to five-year-old, low-income Parisian children whose weight-for-height or height-for-age z scores (WHZ or HAZ) were between — 1 and — 2 SD of the NCHS median. The results were compared to controls who were matched for age, sex, and ethnic origin with WHZ and HAZ between — 1 and + 2 SD. Mean serum levels of transthyretin, albumin and insulin-like growth factor-I and mean plasma zinc concentrations were significantly lower in the growth-impaired children than in the controls ( p = 0.002, p = 0.006, p = 0.015, and p = 0.035, respectively). While the height-retarded children had low mean serum insulin-like growth factor-I values, the weight-retarded subjects had decreased levels of albumin, transthyretin and zinc when compared to controls. Lower mean levels of nutritional markers in healthy, slowly growing children suggest that inadequate dietary intakes of zinc, protein and/or energy may result in marginal delays in weight and height gains. 相似文献
10.
JI Elizalde ; J Clemente ; JL Marin ; J Panes ; B Aragon ; A Mas ; JM Pique ; J Teres 《Transfusion》1997,37(6):573-576
BACKGROUND: Equilibration of hemoglobin concentration after transfusion has been estimated to take about 24 hours, but some studies have shown that earlier measurements reflect steady-state values in persons who have not bled recently. This study was aimed at assessing the changes over time in hemoglobin concentration after transfusion in acutely anemic patients because of recent bleeding. STUDY DESIGN AND METHODS: Thirty-two normovolemic patients recovering from an acute bleeding episode who were no longer thought to be bleeding and who received a 2- unit red cell transfusion were studied. At baseline and 15, 30, 60, and 120 minutes and 24 hours after transfusion, hemoglobin concentration and hematocrit values were measured. RESULTS: The administration of 2 units of packed red cells elicited a 24-hour increase of 22.4 +/− 6.8 g per L in hemoglobin concentration. Hemoglobin values were not different at any of the defined posttransfusion times. Hematocrit levels experienced similar changes over time. Agreement between 15-minute and 24-hour values was excellent, as only 6 percent of patients exhibited a clinically significant difference (> 6 g/L) between the hemoglobin measurements. CONCLUSION: Hemoglobin and hematocrit values rapidly equilibrate after transfusion in normovolemic patients who are recovering from an acute bleeding episode. This fact would allow a rapid assessment of the effects of transfusion and of the recurrence of bleeding in patients remaining at risk. 相似文献