全文获取类型
收费全文 | 802篇 |
免费 | 40篇 |
国内免费 | 17篇 |
专业分类
儿科学 | 6篇 |
妇产科学 | 1篇 |
基础医学 | 105篇 |
口腔科学 | 2篇 |
临床医学 | 71篇 |
内科学 | 168篇 |
皮肤病学 | 1篇 |
神经病学 | 175篇 |
特种医学 | 4篇 |
外科学 | 42篇 |
综合类 | 57篇 |
预防医学 | 21篇 |
眼科学 | 2篇 |
药学 | 139篇 |
中国医学 | 35篇 |
肿瘤学 | 30篇 |
出版年
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 11篇 |
2020年 | 10篇 |
2019年 | 17篇 |
2018年 | 27篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 14篇 |
2014年 | 56篇 |
2013年 | 59篇 |
2012年 | 47篇 |
2011年 | 46篇 |
2010年 | 51篇 |
2009年 | 29篇 |
2008年 | 42篇 |
2007年 | 41篇 |
2006年 | 28篇 |
2005年 | 39篇 |
2004年 | 23篇 |
2003年 | 17篇 |
2002年 | 21篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 12篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 11篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1973年 | 2篇 |
排序方式: 共有859条查询结果,搜索用时 31 毫秒
1.
B. Z. S. Paul G. Vilaire† S. P. Kunapuli J. S. Bennett† 《Journal of thrombosis and haemostasis》2003,1(4):814-820
Summary. The integrin αvβ3 mediates platelet adhesion to the matrix protein osteopontin and likely is the predominant integrin mediating platelet adhesion to the matrix protein vitronectin. To address the mechanism that regulates αvβ3 activity in platelets, we measured the effect of the P2Y1 antagonist adenosine 3'-phosphate-5'-phosphate (A3P5P) and the P2Y12 antagonist AR-C66096 on ADP-stimulated platelet adhesion to osteopontin and vitronectin. Each antagonist completely inhibited platelet adhesion, implying that concurrent stimulation of P2Y1 and P2Y12 was required to activate αvβ3. The reducing agent dithiothreitol and Mn2+ also induced platelet adhesion to osteopontin, but did so without stimulating platelet activation. Thus, these data suggest that ADP stimulation regulates αvβ3 activity by perturbing the conformation of its extracellular domain. The actin polymerization inhibitors cytochalasin D and latrunculin A also induced platelet adhesion to osteopontin and vitronectin. Thus, αvβ3 activity in resting platelets appears to be constrained by the platelet cytoskeleton. Moreover, the effect of these agents was inhibited by A3P5P and AR-C66096 at micromolar and subnanomolar concentrations, respectively, suggesting that subthreshold platelet stimulation by ADP was required. Our data suggest that signals from both Gαq - and Gαi -coupled receptors converge to release cytoskeletal constraints on αvβ3. We propose that the release of cytoskeletal constraints and a concurrent increase in affinity for ligands is responsible for αvβ3-mediated platelet adhesion. 相似文献
2.
心肌缺血再灌注损伤时细胞核被膜钙泵活性特征的研究 总被引:1,自引:0,他引:1
目的 研究心肌缺血再灌注损伤时Ca2 + 、ATP、ADP和AMP对细胞核被膜钙泵 (Ca2 + ATPase)活性的调节。方法 采用大鼠心肌缺血再灌注模型 ,密度梯度分离纯化细胞核 ,定磷法测定Ca2 + ATPase活性。结果 与正常大鼠相比 ,缺血再灌注损伤动物血浆MDA和FFA显著升高 (P <0 0 1) ;细胞核Ca2 + ATPase活性下降 ,对Ca2 + 亲和力降低 ;ADP、AMP对核Ca2 + ATPase活性的影响明显减弱 ;ATP对Ca2 + ATPase的作用在 [ATP]小于 1 0mmol L时 ,与正常细胞Ca2 + AT Pase活性无显著差异 ,浓度增至 2 0mmol L时 ,活性低于正常细胞 ,ATP浓度继续增加 ,核Ca2 + ATPase活性快速增加。结论 心肌缺血再灌注损伤时Ca2 + 、ATP、ADP、AMP对心肌细胞核Ca2 + ATPase活性的影响发生了明显改变 ,其病理生理意义值得进一步探讨。 相似文献
3.
Ma HP Zhou ZH Liang YY Saxena S Warnock DG 《Pflügers Archiv : European journal of physiology》2004,449(1):96-105
Using whole-cell patch-clamp techniques we found that ATP activated an outwardly rectifying current in Daudi human B lymphoma cells under acidic conditions. The substitution of Cl– for gluconate– shifted the reversal potential, while Cl– channel blockers, 4,4-diisothiocyanostibene-2,2-disulfonic acid (DIDS) and 9-anthracene carboxylic acid (9-AC), blocked the current, indicating that ATP induces this current by activating the outwardly rectifying chloride channel (ORCC). The effect of ATP on ORCC was mimicked by ADP, but not by other P2 receptor agonists such as ATPS (a poorly hydrolyzable analog of ATP), 2,3-O-benzoyl-4-benzoyl-ATP (BzATP), and UTP. The ATP-induced ORCC current was completely blocked by 100 M suramin (a P2 receptor antagonist), and was partially blocked by 100 M pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid tetrasodium (PPADS), which is another P2 receptor antagonist. Neither inactivation of G proteins nor elimination of extracellular Ca2+ affected the ATP-induced current, indicating that G protein-coupled P2Y receptors and Ca2+-permeable P2X receptors are not involved. Based on the pharmacological profile and the fact that acidic conditions are required for ATP to activate the ORCC, we suggest that acidic ATP activates the lymphocyte ORCC via a novel pathway, which is not associated with any previously described purinergic receptors. 相似文献
4.
5.
《Anaesthesia and Intensive Care Medicine》2021,22(11):729-737
The clotting cascade is a complex process and is an important survival mechanism. Major haemorrhage and thromboembolic events remain major causes of increased morbidity and mortality. Drugs affecting coagulation have primarily been utilized to treat or reduce the risk of thromboembolic events. However, the recent progress in the management of major trauma and treating coagulopathy has resulted in further research and development of drugs that improve clotting function. Knowledge of drugs used for both clinical circumstances is now required when working in anaesthesia or intensive care. 相似文献
6.
目的 观察心脑通对大鼠凝血功能的影响。方法 心脑通给大鼠连续灌胃8d 后,观察其对大鼠的出血时间、凝血酶时间、凝血酶原时间、部分凝血活酶时间、血小板聚集以及血浆中TXB2 与6 - 酮- PGF1α含量的影响。结果 心脑通0.4g/kg、0.6g/kg、0 .8g/kg 剂量组的出血时间、凝血酶时间、凝血酶原时间、部分凝血活酶时间均较生理盐水组明显延长( P< 0.05) ;且对ADP诱导的血小板聚集有明显抑制作用;血浆中TXB2 与生理盐水组相比含量下降。结论 心脑通有良好的活血化瘀作用。 相似文献
7.
Aziz Elimadi Didier Morin Edith Albengres Anne-Marie Chauvet-Monges Valérie Allain Aimé Crevat Jean-Paul Tillement 《British journal of pharmacology》1997,121(7):1295-1300
- The effects of zidovudine (ZDV) and zidovudine triphosphate (ZDV-3P) on Ca2+-induced mitochondrial permeability transition (MPT), respiratory control ratio (RCR) and ATP synthesis have been investigated on isolated rat liver mitochondria.
- ZDV slightly but significantly decreased RCR and ATP synthesis but was ineffective in inhibiting MPT. In contrast, ZDV-3P did not alter RCR and ATP synthesis but strongly inhibited MPT (IC50=3.0±0.9 μM).
- The effect of ZDV-3P on mitochondrial swelling required a preincubation time. When incubated 10 min with mitochondria, ZDV-3P (8 μM) totally inhibited the rate of swelling.
- ADP, ATP and atractyloside, which are agents known to interact with the mitochondrial adenine nucleotide carrier (ANC), antagonized the effect of ZDV-3P on mitochondrial swelling. Indeed, the IC50 value of ZDV-3P increased from 3.0 to 17.4, 93.6 and 66.5 μM, in the presence of 20 μM, ADP, ATP or atractyloside, respectively.
- ZDV-3P did not displace [3H]-ATP from its mitochondrial binding site(s) whereas ADP and atractyloside did, suggesting that ZDV-3P and [3H]-ATP do not share the same binding sites.
- ZDV-3P did not affect either mitochondrial respiration or ATP synthesis but inhibited Ca2+-dependent mitochondrial swelling. It was concluded that mitochondrial toxic effects observed during the chronic administration of ZDV cannot be related to its active metabolite (ZDV-3P).
8.
The effects of urokinase on ADP breakdown by vessel-wall, platelet aggregation and the related prostaglandin system "in vitro" were investigated. It is confirmed that urokinase does not induce platelet aggregation both in humans and rabbits "in vitro". Conversely, in high concentrations, urokinase inhibits ADP-induced platelet aggregation in human and rabbit platelet-rich plasma. No effects were observed on rabbit platelet thromboxane A2 release and on rat vascular prostacyclin production, both measured by radioimmunoassay of thromboxane B2 and 6-keto-F1 alpha prostaglandin, respectively. Moreover, the incubation of urokinase with vascular endothelium resulted in an increased disappearance rate. 相似文献
9.
目的 观察丹红合剂对家兔血小板聚集的影响.方法 采用随机数字表法将40只大耳白家兔随机分为5组,每组8只,分别为空白对照组(予等容量的0.5%羧甲基纤维素纳),丹红合剂5、2.5、1.25 g/kg组,阿司匹林0.025 g/kg组.各组均按1ml/kg容积灌胃,1次/d,连续给药8d.于末次给药1h后心脏取血,用二磷酸腺苷(ADP)、胶原、花生四烯酸(AA)3种诱导剂进行血小板聚集实验.结果 丹红合剂5、2.5、1.25 g/kg组对ADP诱导的家兔血小板聚集率的抑制率分别为9.4%、5.1%、0.6%,对胶原诱导的家兔血小板聚集抑制率分别为34.5%、11.1%、5.6%;对花生四烯酸(AA)诱导的家兔血小板聚集抑制率分别为21.4%、11.6%、2.3%.结论 丹红合剂具有抑制血小板聚集作用. 相似文献
10.
BackgroundADP ribosylation factor 6 (ARF6) is a member of the Rat sarcoma virus (RAS) superfamily that is involved in the regulation of vesicular trafficking, membrane lipid remodeling, and signaling pathways. Our earlier work discovered that ARF6, as a downstream effector of the Kirsten rat sarcoma viral oncogene (Kras)/extracellular signal-regulated kinases (ERK) signaling pathway, may increase proliferation and induce the Warburg effect in gastric cancer (GC) cells. Additionally, ARF6 appears to be a potential biomarker for predicting the prognosis of GC. Ferroptosis has recently been described as a type of nonapoptotic iron-dependent cell death that is strongly associated with the Kras mutation. Therefore, it is critical to continue investigating the link between ARF6 and ferroptosis.MethodsWe first created ARF6 silenced cancer cell lines with lentivirus transfection. The knockdown efficiency was confirmed through quantitative polymerase chain reaction (qPCR) and western blotting. Subsequently, we used Cell Counting Kit-8 (CCK-8) and malondialdehyde (MDA) assay for lipid peroxidation measurement. Following this, qPCR and western blotting were conducted to clarify the mechanism involved. Finally, immunohistochemistry was used to stain human GC samples.ResultsOur findings established that, whereas ARF6 did not directly regulate lipid peroxidation, it did render GC cells susceptible to oxidative stress, particularly erastin-induced lipid peroxidation. Additionally, our research demonstrated that ARF6 may control capecitabine resistance via several routes.ConclusionsARF6 may play a critical role in the development of GC. 相似文献