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151.
Research on plant viruses in natural ecosystems has been increasing rapidly over the past decade. This paper reviews recent research on the barley and cereal yellow dwarf viruses (B/CYDVs) in grasslands of the western US, beginning with the evidence that the disease caused by these viruses facilitated the invasion of western US grasslands by European annual grasses. Observational and experimental studies of B/CYDVs were carried out along a latitudinal gradient (33.8-48.8°N) from southern California to southern Canada. The prevalence and community composition of B/CYDVs were assessed over a variety of scales and under a range of biotic and abiotic conditions. The findings indicate that both biotic and abiotic factors are important influences on virus ecology and epidemiology. Introduced annual grasses are high-quality hosts that amplify both virus and vector populations in this system, but our research suggests that endemic perennial grasses are critically important for sustaining virus populations in contemporary grasslands largely composed of introduced species. Experiments indicated that increased phosphorus supply to hosts resulted in greater host biomass and higher virus prevalence. Using experimental exclosures, it was found that the presence of grazing vertebrate herbivores increased the abundance of annual grasses, resulting in increased virus prevalence. The results of these studies suggest that patterns of B/CYDV prevalence and coinfection in western US grasslands are strongly shaped by the interactions of host plants, vectors, vertebrate herbivores, and abiotic drivers including nutrients. 相似文献
152.
Pirzad Jahromi G Seidi S Sadr SS Shabanzadeh AP Keshavarz M Kaka GR Hosseini SK Sohanaki H Charish J 《Basic & clinical pharmacology & toxicology》2012,110(6):487-493
In this study, we investigated the therapeutic effects of simvastatin administered in combination with bone marrow stromal cells (BMSCs) following experimentally induced embolic stroke in rats. Effects on infarct volume, brain oedema and neurological deficits were examined. Focal ischaemic brain injury was induced by emblazing a preformed clot into the middle cerebral artery in rats. Animals were administered simvastatin (40 mg/kg) at 1 hr after stroke, or BMSCs (3 × 10(6)) at 24 hr after stroke or a combination of these two treatments. Rats receiving a dose of simvastatin in combination with BMSC administration demonstrated a significant reduction in neurological deficits, a significant reduction in infarct volume and a significant decrease in brain oedema. Our data show that combining simvastatin administration with BMSCs has an additive effect on improving functional outcome in this thromboembolic stroke model. 相似文献
153.
Chen XT Chan ST Hosseini H Layton D Boyd R Alderuccio F Toh BH Chan J 《Autoimmunity》2011,44(5):384-393
Transplantation of bone marrow (BM) engineered to express self-antigen has been shown to protect 100% of young mice from myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), with thymic clonal deletion as a tolerance mechanism. Here, we asked whether aged mice can also be tolerised following transplantation with self-antigen-engineered BM and whether castration-induced thymus regrowth can enhance this outcomes. Then, 50% of aged mice were protected from EAE regardless of castration-induced thymus regrowth. EAE-free and diseased mice demonstrated MOG-specific lymphocyte proliferation and antibody production regardless of castration-induced thymus regrowth, consistent with lack of intrathymic deletion of self-antigen-reactive T cells. Although low chimerism levels (?4%) were observed, EAE-free mice showed significantly higher chimerism levels in lymphocytes in peripheral lymphoid organs compared with thymus. CD4(+)CD25(+) regulatory T cells were elevated in lymph nodes of EAE-free mice. We conclude that transplantation of self-antigen expressing BM protects 50% of aged mice and castration-induced thymic regrowth had no effect on outcomes. Peripheral tolerance mechanisms are implicated since protection is associated with higher chimerism levels in peripheral T and B lymphocytes and with elevated regulatory T cells. 相似文献
154.
Mahmoud Hosseini Hamid Reza Sadeghnia Soodabeh Salehabadi Hassan Alavi Ali Gorji 《Seizure》2009,18(10):695-698
The role of ovarian hormones and nitric oxide (NO) on seizure and their interaction have been widely investigated. The present study carried out to evaluate the effect of chronic administration of l-arginine (lA) and l-NAME (lN) on pentylenetetrazole (PTZ) induced epilepsy in ovariectomized (OVX) and naïve female rats.Fourty-eight female rats were randomly divided into six groups (n = 8) as follows: (1) sham, (2) ovarectomized (OVX), (3) sham-lA, (4) sham-lN, (5) OVX-lA, and (6) OVX-lN.The animals of sham-lA and OVX-lA received daily injection of 500 mg/kg l-arginine (i.p.) during 4 weeks. Sham-lN and OVX-lN were treated by 10 mg/kg l-NAME (i.p.) daily for 4 weeks. The animals of sham and OVX groups received 1 ml/kg saline (i.p.) instead of l-arginine and l-NAME. The latencies to minimal clonic seizures (MCS) and generalized tonic–clonic seizures (GTCS) after intraperitoneal injection of penetylenetetrazole (PTZ, 90 mg/kg) was recorded and compared between groups.A significant increase in the GTCS, but not MCS, latency was seen in OVX rats in comparison with sham-operated animals. Pretreatment of animals with l-NAME resulted in a significant increase in the GTCS and MCS latencies in sham group while no significant effects were seen in OVX rats. On the contrary, while pretreatment with l-arginine had no effects on MCS and GTCS latencies in sham group, a significant decrease in GTCS latency was observed in OVX rats.It is concluded that ovarian sex hormones affect seizure thresholds induced by PTZ and NO has a role on seizures susceptibility following PTZ administration. This NO effect might be differing in the presence or absence of ovarian hormones, but further investigations need to be done. 相似文献
155.
156.
Vitamin C reduces spatial learning deficits in middle-aged and very old APP/PSEN1 transgenic and wild-type mice 总被引:1,自引:0,他引:1
F.E. Harrison A.H. Hosseini M.P. McDonald J.M. May 《Pharmacology, biochemistry, and behavior》2009,93(4):443-450
Alzheimer's disease is a progressive and fatal neurodegenerative disease characterized by a build up of amyloid β (Aβ) deposits, elevated oxidative stress, and deterioration of the cholinergic system. The present study investigated short-term cognitive-enhancing effects of acute intraperitoneal (i.p.) Vitamin C (ascorbate) treatment in APP/PSEN1 mice, a mouse model of Alzheimer's disease. Middle-aged (12 months) and very old (24 months) APP/PSEN1 bigenic and wild-type mice were treated with ascorbate (125 mg/kg i.p.) or the vehicle 1 h before testing on Y-maze spontaneous alternation and Morris water maze tasks. Very old mice performed more poorly on cognitive tasks than middle-aged mice. Ascorbate treatment improved Y-maze alternation rates and swim accuracy in the water maze in both wild-type and APP/PSEN1 mice. Aβ deposits and oxidative stress both increased with age, and acetylcholinesterase (AChE) activity was significantly reduced in APP/PSEN1 compared to wild-type mice. However, the short course of acute ascorbate treatment did not alter Alzheimer-like neuropathological features of plaque deposition, oxidative stress, or AChE activity. These data suggest that ascorbate may have noötropic functions when administered parenterally in high doses and that the mode of action is via an acute, pharmacological-like mechanism that likely modulates neurotransmitter function. 相似文献
157.
Warnholtz A Ostad MA Heitzer T Thuneke F Fröhlich M Tschentscher P Schwedhelm E Böger R Meinertz T Munzel T 《Atherosclerosis》2007,194(2):439-445
Activation of the renin-angiotensin-aldosterone system plays an important role in the pathogenesis of endothelial dysfunction and atherosclerosis. Studies evaluating the effect of AT1-receptor blockers on endothelial dysfunction in patients with coronary artery disease (CAD) revealed mixed results. Studies addressing the effects of AT1-receptor blockers on the coronary and peripheral function in the same study population, are still lacking. We therefore aimed to test the effects of long-term therapy with the AT1-receptor blocker irbesartan (IRB) on both, the coronary and peripheral endothelial function in patients with CAD. Seventy-two patients with CAD were randomly assigned to double-blinded treatment for 6 months with IRB 300 mg per day or placebo, respectively. Coronary and peripheral endothelial function were measured by intracoronary infusion of acetylcholine (final intracoronary concentration 10(-7.3) to 10(-5.6)M) and by determining flow-dependent dilation (FMD) of the brachial artery, respectively. IRB significantly improved FMD, while no change of coronary endothelial function was observed. Interestingly, plasma levels of N(G),N(G)-dimethyl-arginine, and the isoprostane excretion rate were not modified. IRB treatment improves peripheral but not coronary endothelial dysfunction in patients with CAD. Since reduced FMD of the brachial artery has been shown to be associated with a high-cardiovascular event rate, improvement of FMD by IRB may lead to better prognosis of patients with CAD. 相似文献
158.
Hosseini-Farahabadi S Tavakkol-Afshari J Rafatpanah H Farid Hosseini R Khaje Daluei M 《Iranian journal of allergy, asthma, and immunology》2007,6(1):9-14
Allergic asthma is a multifactorial disease, influenced by genetic and environmental factors. Recent family-based studies have revealed evidence for linkage of human chromosomes 5q31-33, 12q15-24, 11q13 and 15q23.6 as regions likely to contain genes related to asthma. Among the candidate genes in these regions are the genes encoding for human interleukin-4, interleukin-13 and interleukin-16. To evaluate this linkage, we examined an Iranian population of patients with asthma. A total of 30 patients with allergic asthma and 50 normal subjects were studied. Allergic asthma was confirmed using skin prick test and spirometry. DNA was extracted from blood cells and IL-4 (-590C>T), IL-13 (R130Q) and IL-16 (-295T>C) polymorphisms were determined by PCR-RFLP method. Out of 30 patients with allergic asthma, the following genotypes for IL-4, IL-13 and IL-16 cytokines were found: IL-4 genotypes consisted of 17 (56.7%) CC, 8 (26.7%) CT and 5 (16.7%) TT; IL-13 genotypes consisted of 11 (36.7%) GG, 13 (43.3%) GA and 6 (20%) AA; IL-16 genotypes consisted of 23 (76.7%) TT and 7 (23.3%) CT. No patient showed CC genotype for IL-16. A higher proportion of case subjects with the C allele for the IL-4, G allele for the IL-13 and T allele for the IL-16 polymorphisms was found compared with the T, A and C alleles, respectively. These results suggest an influence of genetic variability at the promoter of IL-4 gene (-590C>T) and a coding region of IL-13 gene (R130Q) on the occurrence of allergic asthma and no relationship between IL-16 promoter polymorphism (-295T>C) and this disease. 相似文献
159.
160.
Abolfazl Azami Parichehr Pasbakhsh Mohammad Akbari Mohammad Barbarestani Mohammadhosein Ghahremani Mohammadali Shokrgozar Ali Mandegary Amir Kiani Gholamreza Hassanzadeh 《中国神经再生研究》2009,4(12):1068-1072
BACKGROUND: 3, 4-methylenedioxymethamphetamine (MDMA, also known as "ecstasy") has been shown to exhibit neurotoxic effects on the hippocampus. However, exposure to sub-lethal insults of MDMA has been reported to result in neuroprotection. OBJECTIVE: To investigate the effects of MDMA on hippocampal neuronal viability, caspase-3 activity, and mRNA expression of the N-methyI-D-aspartate (NMDA) receptor 2B (NR2B) subunit. DESIGN, TIME AND SETTING: A cytological, in vitro experiment was performed at the Department of Anatomy, School of Medicine, and Department of Toxicology-Pharmacology, Faculty of Pharmacy Tehran University of Medical Sciences in 2008. MATERIALS: MDMA was extracted from ecstasy tablets, which were kindly supplied by the Pharmacology-Toxicology Department, Faculty of Pharmacy, Tehran University of Medical Sciences, Iran. METHODS: Hippocampal neurons were isolated from Wistar rats at gestational day 18. Following primary culture, hippocampal neuronal viability was detected by MTT assay. Varying concentrations of MDMA (100-5 000 μmol/L) were used to determine lethal concentration 50 (LC50), which was around 1 500 μmol/L. Five concentrations of MDMA below 1 500 μmol/L (100, 200, 400, 800, and 1 050 μmol/L) were used for the remaining experiments. After 24 hours of MDMA treatment, NR2B mRNA expression was detected by RT-PCR, and caspase-3 relative activity was determined by colorimetric assay. MAIN OUTCOME MEASURES: Hippocampal neuronal viability, caspase-3 activity, and NR2B mRNA expression. RESULTS: MDMA-induced neurotoxicity in hippocampal neuronal cultures was dose-dependent. In high concentrations (1 000-5 000μmol/L) of MDMA, neuronal viability was decreased. However, with a 500 μmol/L dose of MDMA, neuronal viability was significantly increased (P 〈 0.01). Low concentrations of MDMA (200 and 400μmol/L) significantly decreased caspase-3 activity (P 〈 0.01), whereas high concentrations of MDMA significantly increased caspase-3 activity (P 〈 0.01). NR2B subunit mRNA expression was not significantly altered after 100 -1 050 μmol/L MDMA exposure. CONCLUSION: MDMA exhibits dual effects on hippocampal neuronal viability and caspase-3 activity. These effects are independent from NR2B subunit expression levels. 相似文献