全文获取类型
收费全文 | 2448篇 |
免费 | 216篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 115篇 |
妇产科学 | 111篇 |
基础医学 | 294篇 |
口腔科学 | 114篇 |
临床医学 | 305篇 |
内科学 | 462篇 |
皮肤病学 | 67篇 |
神经病学 | 172篇 |
特种医学 | 43篇 |
外国民族医学 | 1篇 |
外科学 | 185篇 |
综合类 | 60篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 209篇 |
眼科学 | 43篇 |
药学 | 263篇 |
中国医学 | 49篇 |
肿瘤学 | 173篇 |
出版年
2024年 | 9篇 |
2023年 | 55篇 |
2022年 | 137篇 |
2021年 | 171篇 |
2020年 | 129篇 |
2019年 | 141篇 |
2018年 | 185篇 |
2017年 | 142篇 |
2016年 | 134篇 |
2015年 | 115篇 |
2014年 | 126篇 |
2013年 | 181篇 |
2012年 | 247篇 |
2011年 | 222篇 |
2010年 | 125篇 |
2009年 | 83篇 |
2008年 | 105篇 |
2007年 | 117篇 |
2006年 | 75篇 |
2005年 | 54篇 |
2004年 | 37篇 |
2003年 | 30篇 |
2002年 | 18篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1968年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有2685条查询结果,搜索用时 2 毫秒
971.
Marzieh Agha Hosseini Ashraf Alleyassin Fatemeh Sarvi Leila Safdarian Abas Kokab Mehran Fanisalek 《Archives of gynecology and obstetrics》2013,288(5):1131-1136
Background
The aim of this study was to evaluate the effectiveness of Metformin on ovulation and eventual clinical pregnancy in different phenotypes of polycystic ovary syndrome (PCOS).Materials and methods
A total of 359 subjects who had proven PCOS according to Rotterdam criteria were prospectively selected. Patients’ PCOS phenotypes were determined and recorded. All patients were younger than 35 years. Clinical and biochemical assays in all patients were initially obtained. Then patients were divided into two separate groups. One group received both 1,500 mg of Metformin and 1 mg of folic acid per day and the other group received only 1 mg of folic acid for a total of 2 months. Subsequently, all patients underwent ovulation stimulation with 5 mg of Letrozole per day for 5 days followed by an intra-uterine insemination. Finally, ovulation and pregnancy rates were evaluated for all four PCOS phenotypes. Effect of Metformin therapy was evaluated for each group and each phenotype.Results
The pregnancy rate in Metformin and non-Metformin groups were, respectively, as follows: in phenotype A (39.2 vs. 33.7 %, p = 0.270), phenotype B (43.8 vs. 20 %, p = 0.210), phenotype C (44 vs. 20 %, p = 0.064), and phenotype D (36.5 vs. 28.6 %, p = 0.279).Conclusion
Although there was a little improvement in ovulation and pregnancy rates among patients with B and C phenotypes, there was not a statistically significant difference between the two groups. Based on our study, Metformin therapy does not change the ovulation and pregnancy rate. 相似文献972.
973.
974.
Samimi-Rad K Nasiri Toosi M Masoudi-Nejad A Najafi A Rahimnia R Asgari F Shabestari AN Hassanpour G Alavian SM Asgari F 《Archives of virology》2012,157(10):1959-1965
Injecting drug users (IDUs) are the main at-risk population for hepatitis C virus (HCV) transmission. We studied HCV infection, risk factors, and genotype distribution in relation to the year of first injection among Iranian IDUs. Of a total of 126 specimens positive for HCV antibody, 93 (74?%) had detectible HCV RNA, and the NS5B gene was sequenced for 83, with genotype 3a (n?=?48, 58?%) being predominant, followed by 1a (n?=?35, 42?%). Tattooing was an independent predictor for HCV infection. No significant difference was found between HCV genotypes and IDU characteristics. Although there was no change in the distribution of prevalent genotypes before and after 1997, a slight variation in the prevalence was observed (p?=?0.71). The difference in the prevalence of subtypes 1a and 3a (9.1?% in the period 1984-1996 and 18.2?% in the period 1997-2009) during 25?years was 9.1?%. These findings indicate a high prevalence of HCV infection among Iranian IDUs and highlights HCV-3a as the most prevalent subtype for the past 25?years. Harm-reduction strategies appear to be the most important measures to reduce the transmission of HCV in Iran. 相似文献
975.
Taghipour Z Karbalaie K Kiani A Niapour A Bahramian H Nasr-Esfahani MH Baharvand H 《Stem cells and development》2012,21(10):1794-1802
Regarding both the neural crest origin and neuronal potential of stem cells from human exfoliated deciduous teeth (SHED), here, we assessed their potential in addition to neural induced SHED (iSHED) for functional recovery when transplanted in a rat model for acute contused spinal cord injury (SCI). Following transplantation, a significant functional recovery was observed in both groups relative to the vehicle and control groups as determined by the open field locomotor functional test. We also observed that animals that received iSHED were in a better state as compared with the SHED group. Immunohistofluorescence evaluation 5 weeks after transplantation showed neuronal and glial differentiation and limited proliferation in both groups. However, myelin basic protein and chondroitin sulfate proteoglycan NG2-oligodendrocyte markers-were increased and glial fibrillary acidic protein-astrocyte marker-was decreased in the iSHED group in comparison with the SHED group. These findings have demonstrated that transplantation of SHED or its derivatives could be a suitable candidate for the treatment of SCI as well as other neuronal degenerative diseases. 相似文献
976.
Mohammad Khalili Mohammad Mehdi Molaei Ali Asghar Mozaffari Fatemeh Dorreh Giraei Nasiri-far Ehsan 《Comparative clinical pathology》2012,21(6):1183-1185
Sixty-five samples of bulk tank milk were obtained from the largest milk processor in Kerman. All the samples were tested by a commercially indirect ELISA for the detection of anti-bovine viral diarrhea virus (BVDV) antibodies. On the basis of serological results, dairy farms were assigned in four classes (0, 1, 2, and 3). Among these, 38 farms (58.46%) had a moderate to high level of antibody (2 or 3 classes) indicating that there was a possible BVDV infection, or they had recently been infected with BVDV. This is the first study on seroprevalence of BVDV in Kerman dairy farms which shows that the BVDV infection is wide in industrial dairy cattle herds in Kerman. 相似文献
977.
Ramezan Ali Jafari Rezvan Kiani Ali Shahriyari Farzad Asadi Hossein Hamidinejat 《Comparative clinical pathology》2012,21(5):895-899
The aim of the present experiment was to study the alterations in plasma oxidative stress parameters in broiler chicks fed with graded dietary vitamin E whilst infected with Eimeria tenella. Ninety six new-born chicks were assigned into three treatment groups by adding 0, 316 or 562?ppm of vitamin E premix to their regular diet. On day?21, half of the experimental birds were inoculated with 4?×?104 sporulated oocysts of E. tenella per bird; whereas the remaining chicks served as non-infected controls. Blood samples were taken and assayed for total antioxidant activity (TAA), lipid peroxidation level and vitamin E content. Oocyst shedding was also examined in all treatments. Results showed that TAA and vitamin E levels in plasma were not affected by dietary treatment (p?>?0.05). The lowest level of plasma lipid peroxidation (p?<?0.001) was noticed in the chicks treated with 562?ppm of dietary vitamin E, but the difference between the chicks fed a regular diet or 316?ppm dietary vitamin E was not significant (p?>?0.05). The oocyst shedding was the lowest in the chicks treated with 316?ppm dietary vitamin E (p?<?0.001), but there was no significant difference between the other two dietary treatments (p?>?0.05). In conclusion, the addition of vitamin E at a rate of 316?ppm to broiler basal diet can improve cellular defence system against E. tenella infection without any effect on the plasma antioxidant status, but at higher values it may have an adverse effect. 相似文献
978.
Pourakbari B Mamishi S Kohan L Sedighi L Mahmoudi S Fattahi F Teymuri M 《Journal of microbiology, immunology, and infection》2012,45(2):147-150
Lethal toxic encephalopathy due to shigellosis or Ekiri syndrome is a rare complication of shigellosis with a high fatality rate. Data are very limited on factors that can predict this encephalopathy, so we evaluated clinical and laboratory characteristics for these patients. In this study children with extreme toxicity and convulsions followed by rapid neurological deterioration resulting in brain edema and fatal outcome without sepsis and severe dehydration were selected as having lethal toxic encephalopathy. There were 1295 children with shigellosis during the 10 years of the study. Five children (0.4%) had lethal toxic encephalopathy due to shigellosis. Death occurred following rapid neurological detoriation resulting in brain edema despite intensive treatment. Evidence of brain edema may be a prediction factor for death. Early recognition of encephalopathy and measures to prevent brain edema may improve patient outcome. 相似文献
979.
Mirzaie S Rafii F Yasunaga K Yoshunaga K Sepehrizadeh Z Kanno S Tonegawa Y Reza Shahverdi A 《Computers in biology and medicine》2012,42(4):414-421
Monoterpenes from the essential oils of several plants have been shown to enhance the bactericidal activities of nitrofurantoin and furazolidone against the bacteria of Enterobacteriaceae family. In this study, computer-aided molecular modeling and docking techniques have been employed to simulate the theoretical mode of interaction between monoterpenes and Enterobacter cloacae nitroreductase. Enhancement of nitro drug potency in the presence of monoterpenes may be the result of modulation of nitroreductase activity. Binding nitroreductase with monoterpenes may decrease the efficient conversion of toxic reactive intermediates to final products lacking bactericidal activity. 相似文献
980.
Analysis of gene expression profiles needs a complete matrix of gene array values; consequently, imputation methods have been suggested. In this paper, an algorithm that is based on conjugate gradient (CG) method is proposed to estimate missing values. k-nearest neighbors of the missed entry are first selected based on absolute values of their Pearson correlation coefficient. Then a subset of genes among the k-nearest neighbors is labeled as the best similar ones. CG algorithm with this subset as its input is then used to estimate the missing values. Our proposed CG based algorithm (CGimpute) is evaluated on different data sets. The results are compared with sequential local least squares (SLLSimpute), Bayesian principle component analysis (BPCAimpute), local least squares imputation (LLSimpute), iterated local least squares imputation (ILLSimpute) and adaptive k-nearest neighbors imputation (KNNKimpute) methods. The average of normalized root mean squares error (NRMSE) and relative NRMSE in different data sets with various missing rates shows CGimpute outperforms other methods. 相似文献