全文获取类型
收费全文 | 13224篇 |
免费 | 916篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 100篇 |
儿科学 | 265篇 |
妇产科学 | 192篇 |
基础医学 | 1923篇 |
口腔科学 | 110篇 |
临床医学 | 1815篇 |
内科学 | 3261篇 |
皮肤病学 | 254篇 |
神经病学 | 1159篇 |
特种医学 | 558篇 |
外国民族医学 | 3篇 |
外科学 | 1976篇 |
综合类 | 36篇 |
一般理论 | 6篇 |
预防医学 | 596篇 |
眼科学 | 209篇 |
药学 | 875篇 |
中国医学 | 22篇 |
肿瘤学 | 849篇 |
出版年
2023年 | 86篇 |
2022年 | 136篇 |
2021年 | 400篇 |
2020年 | 209篇 |
2019年 | 328篇 |
2018年 | 392篇 |
2017年 | 272篇 |
2016年 | 280篇 |
2015年 | 363篇 |
2014年 | 497篇 |
2013年 | 636篇 |
2012年 | 1028篇 |
2011年 | 1120篇 |
2010年 | 565篇 |
2009年 | 547篇 |
2008年 | 830篇 |
2007年 | 838篇 |
2006年 | 809篇 |
2005年 | 779篇 |
2004年 | 718篇 |
2003年 | 681篇 |
2002年 | 640篇 |
2001年 | 183篇 |
2000年 | 177篇 |
1999年 | 162篇 |
1998年 | 135篇 |
1997年 | 110篇 |
1996年 | 87篇 |
1995年 | 56篇 |
1994年 | 53篇 |
1993年 | 57篇 |
1992年 | 100篇 |
1991年 | 93篇 |
1990年 | 75篇 |
1989年 | 78篇 |
1988年 | 77篇 |
1987年 | 66篇 |
1986年 | 66篇 |
1985年 | 57篇 |
1984年 | 39篇 |
1983年 | 39篇 |
1982年 | 26篇 |
1981年 | 21篇 |
1980年 | 24篇 |
1979年 | 20篇 |
1978年 | 22篇 |
1976年 | 18篇 |
1975年 | 30篇 |
1973年 | 27篇 |
1967年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
AIM: To determine the economic impact (cost-benefit analysis) of childhood varicella vaccination, with the Oka/Merck varicella zoster virus vaccine live (Varivax) in Italy. METHODS: This analysis is based on an epidemiological model of varicella zoster virus (VZV) dynamics adapted to the Italian situation. Cost data (Euro, 2002 values) were collected through a literature review. Several vaccination scenarios were analysed: (i) routine vaccination programme for children aged 1-2 years with different levels of vaccination coverage (90%, 70% and 45%) without any catch-up programme; (ii) routine vaccination programme for children aged 1-2 years with different levels of vaccination coverage (90%, 70% and 45%) completed by a catch-up programme for 6-year-old children over the first 5 years of vaccine marketing; and (iii) routine vaccination programme for children aged 1-2 years with different levels of vaccination coverage (90%, 70% and 45%) completed by a catch-up programme during the first year of vaccine marketing for children aged 2-11 years. PERSPECTIVES: A societal perspective, including both direct and indirect costs, and a health-system perspective, limited to costs supported by Italian Health Authorities, were considered. RESULTS: A routine vaccination programme has a clearly positive impact on chickenpox morbidity. Respectively, 68% and 57% of chickenpox-related hospitalisations and deaths could be prevented with a 90% coverage rate. With vaccination costs being more than offset by a reduction in chickenpox treatment costs in the base case, such a programme could also induce savings from both a societal and a health-system perspective (40% and 12% savings, respectively for a 90% coverage rate). A lower coverage rate reduces cost savings, but there is still a 9% decrease in overall societal costs for a 45% coverage rate. Although the reduction in total societal costs was robust to the sensitivity analyses performed, a slight uncertainty remains regarding cost reduction from a health-system perspective. However, in this latter perspective, even in the worst-case scenario of the sensitivity analysis, routine vaccination programmes may be cost effective, the worst-case scenario for cost parameters leading to cost per life-year gained of Euro2853. Catch-up programmes combined with routine vaccination should lead to further cost reductions from a societal perspective: 15% for a massive catch-up during the first year of vaccine marketing compared with toddlers' vaccination alone, and 11% for a catch-up focused on 6-year-old children for a period of 5 years. However, the impact of catch-up programmes on the costs from an Italian health-system perspective remains close to zero (+/-1%). CONCLUSION: This model suggests, with its underlying assumptions and data, that routine ZVZ vaccination may be cost saving from both a societal and a health system perspective in the base case. In the worst-case scenario of the sensitivity analysis, vaccination remains cost effective. 相似文献
992.
Seeman JI Lipowicz PJ Piadé JJ Poget L Sanders EB Snyder JP Trowbridge CG 《Chemical research in toxicology》2004,17(8):1020-1037
The hypothesis that elevated levels of ammonia-releasing compounds in tobacco and ammonia in mainstream (MS) smoke increase the rate and amount of nicotine evaporation from the particles of MS smoke aerosol was examined by kinetic modeling and experiments with MS cigarette smoke. Computational simulation of a kinetic mechanism describing volatile loss of nicotine, ammonia, and acetic acid from an aqueous solution was used to compute the time-dependent concentration of all species in the model. Because of the high volatility of ammonia relative to that of nicotine, variation over a wide range of initial ammonia concentration had no significant effect upon the rate of loss of nicotine from the model system. The effects of a variation in the volatile loss rate constant for ammonia and for the acid were examined. The simulations show that ammonia is lost from the model solution at a greater rate than nicotine and acid, and the loss of volatile acid has a significant role in the rate and amount of nicotine loss. Simulations with a model system undergoing a continuous steady addition of ammonia showed that high rates of ammonia addition could significantly increase the rate of nicotine volatile loss from the model solution. A series of smoking experiments was performed using blended cigarettes connected to a denuder tube. Deposition of smoke constituents can occur directly from the gas phase and by the deposition of smoke aerosol particles themselves. As nicotine exists >99% in the particle phase of MS smoke, in the absence of particle deposition, denuder tube deposition of nicotine occurs via the evaporation-deposition pathway. Solanesol, a nonvolatile tobacco and smoke terpene, was used to quantify the amount of particle deposition onto the denuder tube. The amount of ammonia deposited on the denuder tube was an order of magnitude greater than that of nicotine, showing that ammonia evaporates from the MS smoke particles much faster than does nicotine. The experimental results were supported and explained by the aqueous model simulations. Included in these experiments are cigarettes that differ in their MS smoke ammonia content by a factor of ca. five. However, an increased amount of MS smoke ammonia does not increase the rate of nicotine loss from the particles. The combined results support the conclusion that ammonia in mainstream smoke has little effect, if any, upon the rate and amount of nicotine evaporation from MS smoke particles. 相似文献
993.
Keller L Beaumont S Liu JM Thoret S Bignon JS Wdzieczak-Bakala J Dauban P Dodd RH 《Journal of medicinal chemistry》2008,51(12):3414-3421
A series of 5-alkylindolobenzazepin-7-ones was synthesized by Suzuki coupling between 3-iodoindole-2-carboxylates and the appropriate alpha-alkylbenzylamino o-boronic acids followed by cyclization to the lactam. Derivatives having a linear alkyl chain at C5 were found to be highly cytotoxic to KB cells with IC50 values in the 30-80 nM range. These compounds also inhibited the polymerization of tubulin with IC50's of 1-2 microM. Compound 4f (( S)-5-ethyl) showed comparable antiproliferative activities (IC50's of 30-70 nM) in a variety of cancer cell lines, cell growth being arrested at the G2/M phase. Compound 4f induced apoptosis in a dose-dependent manner in three different cancer cell lines and was shown to affect cell morphology in a manner consistent with its inhibitory action on tubulin polymerization. Using the experimental model of glioma grafted on the chick chorio-allantoic membrane, local treatment with compound 4f markedly reduced tumor progression. 相似文献
994.
Bruins Slot LA Bardin L Auclair AL Depoortere R Newman-Tancredi A 《Behavioural pharmacology》2008,19(2):145-152
Antipsychotics constitute efficacious augmenting agents in the treatment of anxiety disorders, including refractory obsessive-compulsive disorder. We examined the effects of 36 compounds, including typical, atypical and novel antipsychotics with dual dopamine D2/5-hydroxytryptamine 1A (D2/5-HT1A) actions on marble burying behavior in mice, a putative preclinical test for anxiety disorders. One hour after drug administration, male NMRI mice were placed individually in cages containing 20 marbles, and the total number of marbles buried after 30 min was counted. The selective serotonin reuptake inhibitors, citalopram (2.5-40 mg/kg), fluoxetine (2.5-10 mg/kg) and the benzodiazepine diazepam (2.5-10 mg/kg), reduced the number of buried marbles. The atypical antipsychotic, clozapine (0.16-10 mg/kg), but not its congener olanzapine, was effective in this test. Haloperidol, a typical antipsychotic, also reduced the number of buried marbles, albeit not in a dose-dependent manner. The atypical risperidone was partially active (0.16-0.63 mg/kg), as was the benzamide derivative, amisulpride, albeit at high (10-40 mg/kg) doses. Among the 'third-generation' antipsychotics possessing combined D2/5-HT1A properties, bifeprunox was active at 0.0025 mg/kg, whereas SLV313 and aripiprazole were active only at the highest doses (2.5 and 10 mg/kg, respectively). SSR181507, F15063 and the antidyskinetic agent, sarizotan, were without any effect. Among a series of receptor subtype-selective ligands, only the 5-HT1A agonist, (+)-8-OH-DPAT (0.63-2.5 mg/kg) and the 5-HT2A/2B/2C antagonist, ritanserin (0.63-2.5 mg/kg) were active. Among novel antipsychotics with dual D2/5-HT1A properties, only bifeprunox was able to potently reduce the number of buried marbles. Inhibition of marble burying behavior may result from the interplay of several receptor systems, including 5-HT2 receptor blockade, dopamine D2 partial agonism and serotonin 5-HT1A agonism. 相似文献
995.
996.
Maillet A Congy-Jolivet N Le Guellec S Vecellio L Hamard S Courty Y Courtois A Gauthier F Diot P Thibault G Lemarié E Heuzé-Vourc'h N 《Pharmaceutical research》2008,25(6):1318-1326
Purpose
Despite an increasing interest in the use of inhalation for local delivery of molecules for respiratory diseases and systemic disorders, methods to deliver therapy through airways has received little attention for lung cancer treatment. However, inhalation of anticancer drugs is an attractive alternative route to systemic administration which results in limited concentration of the medication in the lungs, and triggers whole-body toxicity. In this study, we investigated the feasibility of nebulization for therapeutic antibodies, a new class of fully-approved anticancer drugs in oncology medicine.Materials and methods
Cetuximab, a chimeric IgG1 targeting the epidermal growth factor receptor (EGFR), was nebulized using three types of delivery devices: a jet nebulizer PARI LC+®, a mesh nebulizer AeronebPro® and an ultrasonic nebulizer SYST’AM® LS290. Aerosol size distribution was measured using a cascade impactor and aerosol droplets were observed under optical microscopy. The immunological and pharmacological properties of cetuximab were evaluated following nebulization using A431 cells.Results
The aerosol particle clouds generated with the three nebulizers displayed similar aerodynamical characteristics, but the IgG formed aggregates in liquid phase following nebulization with both the jet and ultrasonic devices. Flow cytometry analyses and assays of EGFR-phosphorylation and cell growth inhibitions on A431 demonstrated that both the mesh and the jet nebulizers preserved the binding affinity to EGFR and the inhibitory activities of cetuximab.Conclusions
Altogether, our results indicate that cetuximab resists the physical constraints of nebulization. Thus, airway delivery represents a promising alternative to systemic administration for local delivery of therapeutic antibodies in lung cancer treatment. 相似文献997.
J Michael Conlon Jolanta Kolodziejek Norbert Nowotny Jér?me Leprince Hubert Vaudry Laurent Coquet Thierry Jouenne Jay D King 《Toxicon》2008,52(3):465-473
Peptidomic analysis of norepinephrine-stimulated skin secretions from Hose's rock frog Odorrana hosii (Boulenger, 1891) led to the isolation of 8 peptides with differential antibacterial activities. Structural characterization demonstrated that the peptides belonged to the esculentin-1 (1 peptide), esculentin-2 (1 peptide), brevinin-1 (2 peptides), brevinin-2 (2 peptides), and nigrocin-2 (2 peptides) families of antimicrobial peptides. Similar analysis of skin secretions from the Malaysian fire frog Hylarana picturata (Boulenger, 1920) led to the isolation and characterization of peptides belonging to the brevinin-1 (2 peptides), brevinin-2 (5 peptides), and temporin (1 peptide) families. The differences in antimicrobial activities of paralogous peptides provide insight into structure-activity relationships, emphasizing the importance of cationicity in determining potency. The substitution Lys(11)-->Gln in brevinin-1HSa (FLPAVLRVAAKIVPTVFCAISKKC) from O. hosii abolishes growth inhibitory activity against Escherichia coli but has no effect on the high potency (MIC=8mug/ml) against Staphylococcus aureus. In contrast, the substitution (Gly(4)-->Asp) in brevinin-2PTb (GFKGAFKNVMFGIAKSAGKSALNALACKIDKSC) from H. picturata reduces activity against both E. coli and S. aureus. Cladistic analysis based upon the amino acid sequences of the brevinin-2 peptides from Asian frogs provides evidence for sister taxon relationships between O. hosii and O. livida and between H. picturata and H. güntheri. 相似文献
998.
Nadège Costa Emiel O. Hoogendijk Michael Mounié Robert Bourrel Yves Rolland Bruno Vellas Laurent Molinier Matteo Cesari 《Journal of the American Medical Directors Association》2017,18(5):453.e7-453.e12
Objectives
Pneumonia is a frequent condition in older people. Our aim was to examine the total healthcare cost related to pneumonia in nursing home (NH) residents over a 1-year follow-up period.Design
This was a prospective, longitudinal, observational, and multicenter study that was a part of the Incidence of Pneumonia and related Consequences in Nursing Home Resident study.Setting
Thirteen NHs located in Languedoc Roussillon and Midi-Pyrénées regions in France were included.Participants
Resident in NH, older than 60 years and had a group iso-resource score ranging from 2 to 5.Measurements
Pneumonia events were characterized according to the Observatoire du Risque Infectieux en Geriatrie criteria. Direct medical and nonmedical costs were assessed from the French health insurance perspective. Healthcare resources was retrospectively gathered from the French Social Health Insurance database and valued using the tariffs reimbursed by the French health insurance. Sociodemographic variables, clinical factors, vaccinations, cognition, depression, functional status, frailty index, as well as group iso-resource score were also recorded.Results
Among the 800 patients initially included in the Incidence of Pneumonia and Related Consequences in Nursing Home Resident study, 345 which were listed in the database of the French Social Health Insurance were included in this economic study. Among them, 64 (18%) experienced at least 1 episode of pneumonia during the 1-year follow-up period. Mean annual total additional cost for a patient who experienced at least 1 episode of pneumonia during the 1 year follow-up period is 2813€. On average, total annual costs increased by 60% to 93% when a patient experienced at least 1 episode of pneumonia.Conclusions
NH-acquired pneumonia has a great impact on total cost of care for NH residents. Our results suggest the potential economic savings that could be achieved if pneumonia could be prevented in NHs. 相似文献999.
As a synthetic analogue of adrenocorticotropic hormone (ACTH), tetracosactide is prohibited in sport by the World Anti‐Doping Agency (WADA). An enzyme‐linked immunosorbent assay (ELISA) method is proposed for detection of this drug in plasma. Since its structure corresponds to the 24 N‐terminal of the 39 amino acids of the natural endogenous peptide ACTH, tetracosactide can be detected with a commercial ELISA kit for ACTH that uses antibodies, the epitopes of which are located in the 1?24 part of ACTH. However, an essential condition for detection specificity is the preliminary total clearance of endogenous ACTH in the plasma samples. This is achieved by a preparative step based on cation‐exchange chromatography before ELISA. The method is specific and sensitive (LOD: 30 pg/mL) and may be used as a screening analysis in anti‐doping control. The pre‐analytical conditions are shown to be of the upmost importance and recommendations for blood collection (EDTA tubes), sample transport (4 °C) and plasma sample storage (‐20 °C) are presented. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
1000.
Johan Courjon Patrick Munro Yvonne Benito Orane Visvikis Coralie Bouchiat Laurent Boyer Anne Doye Hubert Lepidi Eric Ghigo Jean-Philippe Lavigne Fran?ois Vandenesch Emmanuel Lemichez 《Toxins》2015,7(10):4131-4142
It is crucial to define risk factors that contribute to host invasion by Staphylococcus
aureus. Here, we demonstrate that the chromosomally encoded EDIN-B isoform from S. aureus contributes to the onset of bacteremia during the course of pneumonia. Deletion of edinB in a European lineage community-acquired methicillin resistant S. aureus (CA-MRSA) strain (ST80-MRSA-IV) dramatically decreased the frequency and magnitude of bacteremia in mice suffering from pneumonia. This deletion had no effect on the bacterial burden in both blood circulation and lung tissues. Re-expression of wild-type EDIN-B, unlike the catalytically inactive mutant EDIN-R185E, restored the invasive characteristics of ST80-MRSA-IV. 相似文献