全文获取类型
收费全文 | 448篇 |
免费 | 15篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 4篇 |
妇产科学 | 18篇 |
基础医学 | 54篇 |
口腔科学 | 4篇 |
临床医学 | 10篇 |
内科学 | 96篇 |
皮肤病学 | 3篇 |
神经病学 | 46篇 |
特种医学 | 5篇 |
外科学 | 26篇 |
综合类 | 30篇 |
预防医学 | 20篇 |
眼科学 | 3篇 |
药学 | 133篇 |
中国医学 | 11篇 |
肿瘤学 | 7篇 |
出版年
2023年 | 2篇 |
2022年 | 13篇 |
2021年 | 7篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 15篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 28篇 |
2012年 | 16篇 |
2011年 | 27篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 19篇 |
2007年 | 23篇 |
2006年 | 18篇 |
2005年 | 28篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 12篇 |
2001年 | 17篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 2篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有472条查询结果,搜索用时 15 毫秒
1.
血小板活化因子在急性肝肾衰竭动物模型中对肾功能的影响 总被引:1,自引:0,他引:1
目的:了解血小板活化因子(PAF)在急性肝、肾衰竭动物模型中对肾功能的影响及可能的作用机制。方法:设4组大鼠,分别注射D-氨基半乳糖(D-GaLN)加内毒素(LPS),D-GaLN加PAF,D-GaLN加LPS加PAF受体拮抗剂及生理盐水,诱导急性肝、肾衰竭动物模型,测肝、肾功能指标并观察肝、肾组织病理改变。结果:注射D-GaLN大鼠的血清丙氨酸氨基转移酶、总胆红素比生理盐水组升高10倍以上,差异有显著性,病检有肝细胞坏死。注射PAF或LPS组与PAF受体拮抗剂组或生理盐水组比,肾功能指标差异有显著性。肾组织病检可见部分肾小管坏死。结论:PAF与急性肝、肾衰竭动物模型中的急性肾衰有关;PAF可能参与了内毒素相关的肝肾综合征(HRS)的形成;PAF受体拮抗剂对HRS可能有治疗作用。 相似文献
2.
Nitric oxide (NO) is a physiological species involved in inhibition of platelet adhesion and aggregation. A novel NO delivery device was utilized to quantitatively assess the effects of gaseous NO on platelet deposition to agonist-coated biomaterials in the presence of a platelet suspension. Platelet deposition was evaluated as a function of agonist (collagen, fibrinogen, or IgG), shear rate (250, 500, and 750 s–1), and perfusion time (5, 7.5, and 15 min). The minimal aqueous surface NO concentrations and fluxes necessary for significant inhibition of platelet deposition were quantified. Platelet deposition was completely inhibited at a gaseous NO exposure of 0.1 ppm, irrespective of the platelet agonist, shear rate, and perfusion time. The corresponding aqueous surface NO concentration was 0.09 nM at 250 s–1 as predicted by a validated model. Surface fluxes ranged between 0.3 and 0.6 femtomoles cm–2 s–1. The results of this study are useful for establishing generalized guidelines (i.e., NO flux requirements in the presence of agonists, shear rate, and perfusion time) for the design and development of suitable biomaterials incorporating NO to reduce platelet deposition. Further studies incorporating blood, rather than platelet suspensions, are required to provide a more complete assessment of the required NO flux necessary to inhibit platelet deposition. © 2000 Biomedical Engineering Society.
PAC00: 8717-d, 8719Tt 相似文献
3.
sa Andersson Susanne M. Grunewald Albert Duschl Alain Fischer James P. Disanto 《European journal of immunology》1997,27(7):1762-1768
The common γ chain (γc) forms a critical component of the receptors for interleukins (IL)-2, IL-4, IL-7, IL-9, and IL-15. We analyzed γc-deficient mice to define a role for γc signaling in the development and function of the macrophage lineage. No major differences in absolute cell numbers, cell surface phenotype, or in vitro function of γ?c compared to γ+c macrophages were observed. We therefore conclude that signaling through the γc chain is not essential for the differentiation of mouse macrophages. Although B and T cells require γc for IL-4 responses, IL-4 up-regulated major histocompatibility class II molecules and inhibited nitric oxide production from γ?c macrophages following stimulation with lipopolysaccharide and interferon-γ. γ?c macrophages could also respond to IL-13, consistent with the model of a type II IL-4 receptor α/IL-13R which can function in the absence of γc. Both IL-4 and IL-13 responses could be completely inhibited with the mouse IL-4 antagonist QY, suggesting that all of the observed IL-13 responses pass through the type II receptor, making it the primary signaling receptor complex for IL-13 in mouse macrophages. 相似文献
4.
Ken Nakazawa Kazuhide Inoue Kannosuke Fujimori Akira Takanaka 《Pflügers Archiv : European journal of physiology》1991,418(3):214-219
The effects of suramin, reactive blue 2 (RB2) and d-tubocurarine (d-TC) were investigated electrophysiologically to elucidate the mechanisms underlying their antagonism of P2 purinoceptor-mediated responses. All three compounds inhibited an adenosine triphosphate (ATP)-activated inward current in rat phaeochromocytoma PC12 cells in a concentration-dependent manner. The order of potency was RB2 > suramin > d-TC. The inhibition induced by suramin or RB2 was reversible, whereas that induced by d-TC was not reversed after a 5-min rinse. The inactivation of the ATP-activated current was accelerated by d-TC but not by suramin or RB2. RB2 administered simultaneously with ATP exerted much weaker inhibition compared to that induced by prior administration, suggesting that RB2 is a slowly acting antagonist. This was not observed for suramin or d-TC. Suramin and RB2 caused a parallel shift in the concentration/response curve for the ATP-activated current. With d-TC the maximal response of ATP was decreased but the concentration producing half-maximal response was unchanged. The voltage dependency of the ATP-activated current showed less inward rectification in the presence of d-TC. Suramin or RB2 did not affect the voltage dependency. These results suggest that suramin and RB2 reversibly block binding of ATP to receptors, whereas d-TC blocks ion permeability through the ATP-activated channel. 相似文献
5.
J. Freedman T. Hökfelt G. Jonsson C. Post 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1986,62(1):175-178
Summary Intrathecal administration of the substance P antagonist Spantide caused marked necrotic changes of the gray matter of the spinal cord extending several segments from the injection site. Intravenous treatment with several doses of thyrotropin releasing hormone before and after Spantide injection completely prevented the necrotic lesion. 相似文献
6.
Kellis E 《European journal of applied physiology》2003,89(3-4):271-280
The examination of the moment exerted by the hamstrings during maximum isokinetic knee extensor tests is useful when comparing
isokinetic strength and muscle activity patterns between children and adults. The purpose of this study was to examine the
effect of antagonist moment of the hamstrings on the isokinetic moment of the knee extensors in pubertal children and to determine
whether this effect is altered following a fatigue task. Eighteen healthy pubertal males [age 14.3 (0.5) years] performed
34 maximal isokinetic concentric efforts of the knee extensors at 60°·s−1. The average moment of force and electromyographic (aEMG) signal of vastus medialis (VM), vastus lateralis (VL) and biceps
femoris (BF) at 11–30°, 31–50°, 51–70° and 71–90° of knee flexion were calculated for each repetition. The hamstrings antagonist
moment was determined before and after the fatigue task by fitting the aEMG–moment relationship at different levels of muscle
effort using second-degree polynomials. The percentage contribution of the antagonist moment to the resultant joint moment
ranged from 7.1 % to 60.4 % throughout the range of motion, with the highest percentage observed close to full knee extension
(11–30°). The antagonist effect was significantly greater during concentric tests of the knee extensors compared to the corresponding
eccentric tests (p<0.05). Following the fatigue test, there was an overall decline of the resultant joint moment, but no changes in the predicted
hamstrings moment were observed. These results indicate that when testing maximal knee extensor isokinetic strength in pubertal
boys, activity of the hamstrings implies a reduction of the net extensor moment as compared to the isolated capacity of the
knee extensors. However, this antagonist effect is not altered following the performance of an isokinetic fatigue knee extension
task.
Electronic Publication 相似文献
7.
8.
B. Denis A. Lefort R. M. Flipo F. Tubach M. Lemann P. Ravaud D. Salmon X. Mariette O. Lortholary 《Clinical microbiology and infection》2008,14(2):183-186
This study investigated the long-term outcome of patients with tuberculosis (TB) as a complication of tumour necrosis factor (TNF)-α blocker therapy. All TB cases ( n = 21) complicating TNF-α blocker therapy from French university hospitals were collated between January 2000 and September 2002. Outcome was assessed via a postal questionnaire during September 2005. The mortality rate after 4 years was 4.8%, and one patient had relapsed and six (29%) patients had recommenced TNF-α antagonist treatment, after appropriate anti-TB therapy, without reactivation. These data support the concept that TNF-α antagonists can be restarted in TB patients provided that adequate anti-TB treatment has been completed. 相似文献
9.
Sven-Åke Persson 《Psychopharmacology》1978,59(2):113-116
In the rat, lysergic acid diethylamide (LSD) 0.5 mg/kg and 2-bromo lysergic acid diethylamide (BOL) 0.5 mg/kg increased the rate of the striatal in vivo tyrosine hydroxylation as measured by the DOPA accumulation after decarboxylase inhibition. Neither LSD nor BOL significantly changed the DOPA accumulation in the olfactory tubercle, a dopamine-rich part of the limbic system. LSD but not BOL increased the DOPA accumulation in the cerebral cortex and in the brain stem. LSD and BOL appeared not to alter the rate of -MT-induced disappearance of DA or of NA in the whole brain, nor did they change the rate of the -MT-induced disappearance of DA in the striatum. It is suggested that in the striatum LSD and BOL block autoreceptors (presynaptic receptors) regulating the tyrosine hydroxylation. These receptors may be DA receptors, but may also be 5-HT- or LSD-sensitive receptors.The regional differences observed between LSD and BOL suggest that LSD in the cerebral cortex and in the brain stem increases the DOPA accumulation by mechanism other than that functioning in the striatum. One possible explanation is that LSD and BOL may differ in their effects on 5-hydroxytryptaminergic systems in the cerebral cortex and in the brain stem. 相似文献
10.
M. Margaret Wierzbicka Allen W. Wiegner 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1992,91(3):509-519
Summary By using a mathematical model and experiments involving electrical simulation of antagonistic muscles, we have formed the hypothesis (Wierzbicka et al. 1986) that in one-joint movements the antagonist muscle not only provides braking torque but also controls movement time. To get additional experimental support for this hypothesis, we studied elbow flexion movements performed by patients with spinal cord injury at the C 5–6 level who had relatively normal strength in their biceps muscle and little or no voluntary control of the triceps. Seven quadriplegic patients and six control subjects performed elbow flexion movements of 10°, 20°, and 30° as fast and accurately as possible. Despite the lack of antagonist, patients used the same pulse height strategy as control subjects to scale their responses with movement amplitude. However, patients' movement time was on average twice that of control subjects, and durations of both accelerative and decelerative phases of movement were increased. Movement speed and acceleration were reduced to 20–50% of the corresponding values of control subjects. Patients tended to overshoot the target to a larger extent than control subjects, particularly 10° targets, with nearly twice the error. We performed the same experiments using an external torque motor to assist the weak triceps. When a constant extensor torque of 2.5 or 5 Nm was provided by the motor, patients were able to move faster, and movement accuracy improved to within the normal range. These results provide direct evidence that the lack of an antagonist has an important effect on completion time and accuracy of fast goal-directed movements. 相似文献