全文获取类型
收费全文 | 1625篇 |
免费 | 89篇 |
国内免费 | 114篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 95篇 |
妇产科学 | 29篇 |
基础医学 | 192篇 |
口腔科学 | 33篇 |
临床医学 | 197篇 |
内科学 | 365篇 |
皮肤病学 | 39篇 |
神经病学 | 71篇 |
特种医学 | 369篇 |
外国民族医学 | 1篇 |
外科学 | 62篇 |
综合类 | 56篇 |
预防医学 | 81篇 |
眼科学 | 34篇 |
药学 | 86篇 |
中国医学 | 2篇 |
肿瘤学 | 115篇 |
出版年
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 19篇 |
2016年 | 28篇 |
2015年 | 28篇 |
2014年 | 19篇 |
2013年 | 45篇 |
2012年 | 27篇 |
2011年 | 38篇 |
2010年 | 57篇 |
2009年 | 56篇 |
2008年 | 32篇 |
2007年 | 88篇 |
2006年 | 50篇 |
2005年 | 66篇 |
2004年 | 32篇 |
2003年 | 27篇 |
2002年 | 28篇 |
2001年 | 24篇 |
2000年 | 29篇 |
1999年 | 28篇 |
1998年 | 97篇 |
1997年 | 98篇 |
1996年 | 108篇 |
1995年 | 65篇 |
1994年 | 63篇 |
1993年 | 68篇 |
1992年 | 14篇 |
1991年 | 33篇 |
1990年 | 28篇 |
1989年 | 54篇 |
1988年 | 44篇 |
1987年 | 49篇 |
1986年 | 31篇 |
1985年 | 47篇 |
1984年 | 25篇 |
1983年 | 20篇 |
1982年 | 26篇 |
1981年 | 24篇 |
1980年 | 31篇 |
1979年 | 10篇 |
1978年 | 12篇 |
1977年 | 18篇 |
1976年 | 29篇 |
1975年 | 21篇 |
1973年 | 13篇 |
1972年 | 6篇 |
1970年 | 8篇 |
排序方式: 共有1828条查询结果,搜索用时 46 毫秒
1.
Najat C Daw Wayne L Furman Clinton F Stewart Lisa C Iacono Mark Krailo Mark L Bernstein Janet E Dancey Rose Anne Speights Susan M Blaney James M Croop Gregory H Reaman Peter C Adamson 《Journal of clinical oncology》2005,23(25):6172-6180
PURPOSE: Epidermal growth factor receptor is expressed in pediatric malignant solid tumors. We conducted a phase I trial of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in children with refractory solid tumors. PATIENTS AND METHODS: Gefitinib (150, 300, 400, or 500 mg/m2) was administered orally to cohorts of three to six patients once daily continuously until disease progression or significant toxicity. Pharmacokinetic studies were performed during course one (day 1 through 28). RESULTS: Of the 25 enrolled patients, 19 (median age, 15 years) were fully evaluable for toxicity and received 54 courses. Dose-limiting toxicity was rash in two patients treated with 500 mg/m2 and elevated ALT and AST in one patient treated with 400 mg/m2. The maximum-tolerated dose was 400 mg/m2/d. The most frequent non-dose-limiting toxicities were grade 1 or 2 dry skin, anemia, diarrhea, nausea, and vomiting. One patient with Ewing's sarcoma had a partial response. Disease stabilized for 8 to > or = 60 weeks in two patients with Wilms' tumor and two with brainstem glioma (one exophytic). At 400 mg/m2, the median peak gefitinib plasma concentration was 2.2 microg/mL (range, 1.2 to 3.6 microg/mL) and occurred at a median of 2.3 hours (range, 2.0 to 8.3 hours) after drug administration. The median apparent clearance and median half-life were 14.8 L/h/m2 (range, 3.8 to 24.8 L/h/m2) and 11.7 hours (range, 5.6 to 22.8 hours), respectively. Gefitinib systemic exposures were comparable with those associated with antitumor activity in adults. CONCLUSION: Oral gefitinib is well tolerated in children. Development of the drug in combination with cytotoxic chemotherapy will be pursued. 相似文献
2.
Paul R Gard Pauline Daw Zhila Sayyad Mashhour Paula Tran 《Journal of the renin-angiotensin-aldosterone system》2007,8(3):133-138
INTRODUCTION: Angiotensin (Ang) IV enhances learning and memory in rats but there are strain differences in its effects in mice. Oxytocin (OT) also influences learning and memory in rats and mice and, in the light of the proposed effects of Ang IV on oxytocinase, the hypothesis that the effects of Ang IV on cognition in mice involve OT was tested. MATERIALS AND METHODS: The effects of Ang IV and OT, alone and combined, were determined in rat isolated uterine smooth muscle and in object recognition and forced swim tests in BKW mice. RESULTS: Ang potentiated the contractile effects of OT in the uterus. Neither peptide had any effect on object recognition nor locomotor activity. Ang IV had no effect in the forced swim test but abolished the effects of OT. CONCLUSIONS: Ang IV influences the actions of OT in vitro and in vivo, possibly by inhibition of oxytocinase, but the lack of effect of Ang IV on object recognition in BKW mice is unlikely to be a consequence of a deficiency endogenous OT. Unlike OT, Ang IV alone has no effect on learned helplessness in the forced swim test, an effect often used to predict potential antidepressant efficacy in humans. 相似文献
3.
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
4.
5.
6.
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
7.
8.
9.
10.
The effect of age on binding of MK-801 in the cat visual cortex. 总被引:3,自引:0,他引:3
We have examined the effect of age on the binding of (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10-imine maleate (MK-801) in the cat visual cortex. We hypothesized that this binding might change with age because: (1) MK-801 binds to a site associated with the N-methyl-D-aspartate (NMDA) receptor; (2) the NMDA receptor complex has been implicated in neural plasticity; (3) plasticity in the cat visual cortex is age dependent. We used standard receptor binding techniques to measure MK-801 binding in membrane homogenates in cats aged 7 days (d), 21 d, 43 d, 83 d, 7-8 months (mo) and over 2 years. Glutamate (100 microM), glycine (30 microM) and spermidine (20 microM) were used to enhance binding. We found that MK-801 binding is maximal at about 6 weeks of age, decreases slightly by 83 days and then decreases more dramatically in adults. Saturation analysis showed that the of binding with age resulted from variation in number of binding sites and not from variation in affinity. The ability of Mg2+ to inhibit MK-801 binding did not change with age. Dark rearing did not alter the development of MK-801 binding sites. 相似文献