全文获取类型
收费全文 | 4378篇 |
免费 | 304篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 41篇 |
儿科学 | 99篇 |
妇产科学 | 91篇 |
基础医学 | 631篇 |
口腔科学 | 114篇 |
临床医学 | 440篇 |
内科学 | 873篇 |
皮肤病学 | 104篇 |
神经病学 | 297篇 |
特种医学 | 129篇 |
外国民族医学 | 2篇 |
外科学 | 592篇 |
综合类 | 65篇 |
现状与发展 | 1篇 |
预防医学 | 282篇 |
眼科学 | 292篇 |
药学 | 342篇 |
中国医学 | 96篇 |
肿瘤学 | 224篇 |
出版年
2023年 | 42篇 |
2022年 | 111篇 |
2021年 | 194篇 |
2020年 | 148篇 |
2019年 | 187篇 |
2018年 | 227篇 |
2017年 | 155篇 |
2016年 | 217篇 |
2015年 | 175篇 |
2014年 | 241篇 |
2013年 | 295篇 |
2012年 | 485篇 |
2011年 | 405篇 |
2010年 | 240篇 |
2009年 | 150篇 |
2008年 | 238篇 |
2007年 | 261篇 |
2006年 | 207篇 |
2005年 | 156篇 |
2004年 | 116篇 |
2003年 | 92篇 |
2002年 | 92篇 |
2001年 | 12篇 |
2000年 | 9篇 |
1999年 | 13篇 |
1998年 | 21篇 |
1997年 | 9篇 |
1996年 | 12篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 17篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 16篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 13篇 |
1974年 | 4篇 |
1973年 | 7篇 |
排序方式: 共有4715条查询结果,搜索用时 31 毫秒
991.
S. Hossein Fatemi Timothy D. Folsom Teri J. Reutiman Hao Huang Kenichi Oishi Susumu Mori 《European neuropsychopharmacology》2009,19(9):648-653
The hippocampus governs memory formation and emotional regulation, and there is widespread evidence of hippocampal dysfunction in psychiatric disorders, including schizophrenia and autism. There is abundant evidence that prenatal viral infection may play a role in the development of these two disorders. In the current study, we have examined gene expression and structural changes of the hippocampi of exposed neonates following maternal infection at embryonic day (E) 16 (middle second trimester). We observed significant changes in gene expression in the offspring at postnatal day (P) 0 (birth), P14 (childhood), and P56 (adulthood), including a number of candidate genes for autism and schizophrenia. qRT-PCR verified the direction and magnitude of change for 5 of the genes from the microarray data set and revealed mRNA changes for additional genes associated with schizophrenia and autism. MRI revealed a decrease in hippocampal volume at P35 (adolescence). Our results demonstrate altered gene expression and reduced hippocampal volume in the offspring following prenatal viral infection at E16. 相似文献
992.
993.
Abbas Salehiomran Hossein Ahmadi Abbasali Karimi Mokhtar Tazik Samaneh Dowlatshahi Mahmood Sheikh Fathollahi Seyed Hesameddin Abbasi 《Central European Journal of Medicine》2009,4(3):286-292
Transfusion after cardiac surgery is very common. This rate varies between institutions and has remained high despite established
transfusion guidelines. We analyzed our database of patients who underwent isolated CABG (Coronary Artery Bypass Graft) to
determine the predictive factors of homologous transfusion and associated postoperative morbidity, mortality and resource
utilization. All 14,152 patients who underwent first-time isolated CABG, with or without cardiopulmonary bypass (CPB) who
had postoperative homologous transfusion between February 2002 and March 2008 in Tehran Heart Center, were evaluated retrospectively.
Overall, 16.5% of patients received transfusion. Transfused patients demonstrated a significantly higher incidence of postoperative
complications (cardiac, infectious, ischemic, reoperation) and mortality (p<0.001). Homologous blood transfusion effect on
mortality, morbidity and resource utilization. By Multivariable logistic regression analysis adjusted for confounders: Homologous
blood transfusion effect on Mortality (30-days) (OR=3.976, p<0.0001), Prolonged ventilation hours (OR=4.755, p<0.0001), Total
ICU hours (β =14.599, p<0.0001), Hospital length of stay (β =1.141, p<0.0001), Post surgery length of stay (β =0.955, p<0.0001).
We conclude that the isolated CABG patients receiving blood transfusion have significantly higher mortality, morbidity and
resource utilization. Homologous blood transfusion is an independent factor of increased resource utilization, morbidity and
mortality. 相似文献
994.
Akram Jamshidzadeh Maryam Baghban Negar Azarpira Afshin Mohammadi Bardbori Hossein Niknahad 《Food and chemical toxicology》2008,46(12):3612-3615
Tomato products containing lycopene are believed to be associated with decreased risk of chronic diseases including cancer, and its effects are suggested to be due to antioxidant effect of lycopene. The aim of this research was to study the effects of tomato extract on acetaminophen (APAP), amiodarone (ADN) and cyclosporine A (CsA)-induced liver, lung and kidney toxicity, respectively. Previous studies have shown that free radical reactions may play important roles in toxicity of these drugs. Rats received a single dose of APAP (750mg/kg, i.p.) before treatment with tomato extract (5mg/kg, oral) for seven consecutive days, ADN (100mg/kg, i.p.) plus tomato extract (5mg/kg, oral) for 10 consecutive days, or CsA (250mg/kg, i.p.) plus tomato extract (5mg/kg, oral) for 14 consecutive days. At the end of each treatment, the animals were sacrificed and the related organ tissues were collected for biochemical and histopathological examinations. Simultaneous treatment of tomato extract ameliorated tissue damage, biochemical indices, and oxidative stress parameters against APAP-induced acute hepatotoxicity, but had less beneficial effects on ADN-induced lung toxicity and little effect against CsA-induced nephrotoxicity. Therefore, tomato products may be beneficial for the prevention and therapy of toxicity induced by ADN and APAP. 相似文献
995.
Ahmad A. Noorbala Fatemeh Ramazanzadeh Hossein Malekafzali Nasrin Abedinia Abbas R. Forooshani Mamak Shariat Mina Jafarabadi 《International journal of gynaecology and obstetrics》2008,101(3):248-252
OBJECTIVE: To determine factors affecting depression in infertile couples and the impact of a psychological intervention before or during infertility treatment. METHODS: In a cross-sectional study with 638 infertile couples assessed for depression, 140 couples with a member who had a Beck Depression Inventory (BDI) score of 17 or higher were randomized to receive psychological treatment either before or during infertility treatment. Logistic regression was performed to eliminate confounding factors. RESULTS: Depression was initially found in 48% of women and 23.8% of men. The mean+/-SD Beck scores fell from 18.7+/-9.7 to 10.7+/-5.8 (P<0.001) in the group psychologically treated before they received infertility treatment. CONCLUSION: The psychological intervention was found useful in alleviating depression in infertile couples before they received infertility treatment. 相似文献
996.
Hossein Mortazavi M.D. Pardis Hejazi M.D. Nessa Aghazadeh M.D. Hamed Esfandiari M.D. Alireza Ghanadan M.D. Issa Jahanzad M.D. 《Pediatric dermatology》2015,32(1):e39-e41
We herein report two patients with hydroa vacciniforme and concomitant ophthalmic involvement, primarily in the form of keratoconjunctivitis leading to corneal opacity. Awareness of this occasional manifestation may help to prevent severe complications. 相似文献
997.
Naser Kamyari Ali Reza Soltanian Hossein Mahjub Abbas Moghimbeigi 《JMIR Public Health and Surveillance》2021,7(1)
BackgroundNutrition is not a treatment for COVID-19, but it is a modifiable contributor to the development of chronic disease, which is highly associated with COVID-19 severe illness and deaths. A well-balanced diet and healthy patterns of eating strengthen the immune system, improve immunometabolism, and reduce the risk of chronic disease and infectious diseases.ObjectiveThis study aims to assess the effect of diet, nutrition, obesity, and their implications for COVID-19 mortality among 188 countries by using new statistical marginalized two-part models.MethodsWe globally evaluated the distribution of diet and nutrition at the national level while considering the variations between different World Health Organization regions. The effects of food supply categories and obesity on (as well as associations with) the number of deaths and the number of recoveries were reported globally by estimating coefficients and conducting color maps.ResultsThe findings show that a 1% increase in supplementation of pulses reduced the odds of having a zero death by 4-fold (OR 4.12, 95% CI 11.97-1.42). In addition, a 1% increase in supplementation of animal products and meat increased the odds of having a zero death by 1.076-fold (OR 1.076, 95% CI 1.01-1.15) and 1.13-fold (OR 1.13, 95% CI 1.0-1.28), respectively. Tree nuts reduced the odds of having a zero death, and vegetables increased the number of deaths. Globally, the results also showed that populations (countries) who consume more eggs, cereals excluding beer, spices, and stimulants had the greatest impact on the recovery of patients with COVID-19. In addition, populations that consume more meat, vegetal products, sugar and sweeteners, sugar crops, animal fats, and animal products were associated with more death and less recoveries in patients. The effect of consuming sugar products on mortality was considerable, and obesity has affected increased death rates and reduced recovery rates.ConclusionsAlthough there are differences in dietary patterns, overall, unbalanced diets are a health threat across the world and not only affect death rates but also the quality of life. To achieve the best results in preventing nutrition-related pandemic diseases, strategies and policies should fully recognize the essential role of both diet and obesity in determining good nutrition and optimal health. Policies and programs must address the need for change at the individual level and make modifications in society and the environment to make healthier choices accessible and preferable. 相似文献
998.
Marzabadi Esfandiar Azad Meftahi Gholam Hossein Refahi Soheila 《Lasers in medical science》2022,37(5):2403-2412
Lasers in Medical Science - Low-level laser therapy (LLLT) and methylene blue (MB) were proved to have neuroprotective effects. In this study, we evaluated the preventive effects of LLLT and MB... 相似文献
999.
Maryam Samsami Minoosh Shabani Mohammadreza Hajiesmaeili Maria Tavakoli-Ardakani Seyed Hossein Ardehali Alireza Fatemi Saghar Barati Omid Moradi Zahra Sahraei 《Journal of infection and chemotherapy》2021,27(8):1181-1185
IntroductionNephrotoxicity remains a major long-standing concern for colistin, and it is critical to find agents that can prevent it. The present study aims to investigate the effect of vitamin E on the prevention of colistin-induced nephrotoxicity based on its antioxidant and free radical scavenging properties.MethodsA randomized clinical trial was designed for 52 patients taking colistin. These patients were categorized into two groups of equal size, receiving colistin or colistin plus vitamin E (α-Tocopherol). Vitamin E with doses of 400 units was administrated daily either orally or by a nasogastric tube if needed. The incidence of Acute Kidney Injury (AKI) and its duration was recorded based on RIFLE criteria.ResultsThe Incidence of AKI based on RIFLE criteria was 42.3% and 46.2% in intervention and control groups, respectively. The analysis showed no significant difference in the prevalence of AKI for the two groups (P = 0.78). There was no significant difference in the duration of AKI neither (P = 0.83).ConclusionAlthough vitamin E is a powerful biological antioxidant, the effects of Vitamin E prophylaxis on colistin-induced nephrotoxicity was not taken into consideration in this study. 相似文献
1000.
Narjes Mohammadi Bandari Hossein Keyvani Mohammad Abootaleb 《Indian journal of medical microbiology》2022,40(2):245-249
PurposeThe current study aimed to determine blaKPC, blaGES, blaVIM, blaNDM, blaOXA-23, and blaOXA-48 genes in clinical strains of Klebsiella pneumoniae isolated in Tehran, Iran to assess genetic diversity using MLVA as a typing method.MethodsA total of 181 K. pneumoniae isolates were obtained from various clinical samples. CLSI 2018 (clinical and laboratory standards institute) guidelines were used to determine antibiotic susceptibility and the Modified Hodge Test (MHT).To detect blaKPC, blaGES, blaVIM, blaNDM, blaOXA-23, and blaOXA-48, the polymerase chain reaction (PCR) method was used. The MLVA method was used to type K. pneumoniae isolates by using PCR for 8 Variable Number Tandem Repeats (VNTRs).ResultsImipenem was the most effective antibiotic against K. pneumoniae, with 36.5% susceptibility. 100 (55.24%) of the isolates tested positive for KPC, and 30 (30%) tested positive for six genes. Thirty MLVA genotypes were distinguished, and an examination of diversity indexes (DIs) for eight loci revealed that seven different alleles were the most polymorphic, with the highest DI of 0.780.ConclusionsThe present study showed that MLVA could be helpful for typing clinical strains of K. pneumoniae. Our K. pneumoniae isolates are thought to be derived from a small number of clones that have undergone minor genetic changes over time. The results also showed that this method had great potential to differentiate those strains with high phenotypic similarity. The current study has revealed some intriguing facts about K. pneumoniae genetic relatedness in Tehran, Iran. 相似文献