首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3224篇
  免费   177篇
  国内免费   32篇
耳鼻咽喉   18篇
儿科学   115篇
妇产科学   79篇
基础医学   517篇
口腔科学   37篇
临床医学   252篇
内科学   904篇
皮肤病学   41篇
神经病学   403篇
特种医学   84篇
外科学   227篇
综合类   9篇
预防医学   165篇
眼科学   35篇
药学   218篇
中国医学   10篇
肿瘤学   319篇
  2024年   10篇
  2023年   29篇
  2022年   62篇
  2021年   104篇
  2020年   58篇
  2019年   60篇
  2018年   108篇
  2017年   80篇
  2016年   72篇
  2015年   101篇
  2014年   118篇
  2013年   175篇
  2012年   259篇
  2011年   242篇
  2010年   135篇
  2009年   145篇
  2008年   241篇
  2007年   226篇
  2006年   218篇
  2005年   194篇
  2004年   207篇
  2003年   156篇
  2002年   146篇
  2001年   30篇
  2000年   25篇
  1999年   38篇
  1998年   34篇
  1997年   28篇
  1996年   21篇
  1995年   10篇
  1994年   20篇
  1993年   18篇
  1992年   8篇
  1991年   4篇
  1990年   5篇
  1989年   4篇
  1988年   5篇
  1987年   4篇
  1986年   7篇
  1984年   4篇
  1983年   4篇
  1980年   1篇
  1978年   2篇
  1977年   2篇
  1974年   1篇
  1972年   1篇
  1971年   2篇
  1969年   2篇
  1967年   2篇
  1966年   3篇
排序方式: 共有3433条查询结果,搜索用时 15 毫秒
51.
PURPOSE: This collaborative study by three Italian groups of child neuropsychiatrists was carried on to evaluate the efficacy and safety of the classic 4:1 ketogenic diet as add-on treatment in refractory partial or generalized epilepsy in children, adolescents and young adults. METHODS: We performed a prospective add-on study in 56 refractory epilepsy young patients (age 1-23 years, mean 10.4 years), all with both symptomatic and cryptogenic, generalized or partial epilepsies. Child neuropsychiatrists worked with nutritional team for sample selection and patients management. The ketogenic diet was added to the baseline antiepileptic drugs and the efficacy was rated according to seizure type and frequency. During treatment, seizure frequency, side effects, urine and blood ketone levels and other parameters were systematically evaluated. RESULTS: Patients have been treated for 1-18 months (mean 5 months). A >50% reduction in seizure frequency was gained in 37.5 and 26.8% of patients after 3 and 6 months, respectively, at 12 months, this number fell by 8.9%. No significant relationship between diet efficacy and seizure or epilepsy type, age at diet onset, sex and etiology of epilepsy was noted. Nevertheless, it seems noteworthy that 64% of our patients with neuronal migration disorders improved on this diet. Adverse effects occurred, mainly in the first weeks of treatment, in 32 patients (57.1%), but were generally mild and transient. In seven patients (12.5%) it was possible to withdraw one to two AED after 3-4 months on ketogenic diet. CONCLUSION: This initial experience with the ketogenic diet was effective in difficult-to-treat patients with partial and generalized epilepsies, though its efficacy dropped significantly by 9-12 months.  相似文献   
52.
53.
54.
Purpose: LHRH analogues are commonly used in in vitro fertilization protocols to induce hypogonadotropic hypogonadism. The aim of our study was to evaluate the action of the LHRH agonist leuprorelin on the E2 steroidogenesis of human preovulatory granulosa cells. Results: FSH causes a significant increase in E2 production which is double that of the basal condition (P<0.01). At concentrations of 1, 10, and 100 ng/ml, leuprorelin does not produce any modification with respect to the basal condition during the 24- or 72-hr culture period. The FSH, added at different analogue concentrations, produces a significant increase in E2 production as compared to the basal condition (P<0.05) and the E2 production percentage is similar to the values obtained with FSH alone during the 24- or 72-hr culture period. Conclusions: Leuprorelin has no effect on the in vitro E2 production at any concentration. The treatment with different doses of leuprorelin does not suppress FSH-stimulated E2 production. Our findings suggest that human granulosa cells are not acutely sensitive to a direct action on E2 steroidogenesis by LHRH analogues.  相似文献   
55.
56.
In this MEG study we investigated the differences in responses to somatosensory electrical stimuli between primary (SI) and secondary (SII) sensory cortices using 10 different levels of stimulus intensity, starting from below the sensory threshold up to a weak painful level. SI dipole source linearly increased in amplitude as the stimulus intensity raised up to a strong motor level and then saturated at higher stimulation levels. The contralateral and ipsilateral SII dipole source strengths followed the stimulus intensity growing up to the motor threshold, but showed a decrease at the strong motor level, followed by an increase as the stimulus intensity raised towards the weak painful threshold. These results suggest different responses of SI and SII cortices as the intensity of stimulation rises from non-painful to painful values.  相似文献   
57.
58.
The aim of the present study was to test a possible effect of the monoamine oxidase A (MAOA) and serotonin receptor 2A (5-HT-2A) gene variants on the antidepressant activity of fluvoxamine and paroxetine in a sample of major (n = 248) and bipolar (n = 195) depressives, with or without psychotic features. A total of 443 in-patients were treated with 300 mg fluvoxamine (n = 307) or 20-40 mg paroxetine (n = 136) for 6 wk. The severity of depressive symptoms was assessed weekly with the Hamilton Rating Scale for Depression (HAMD). Allele variants were determined in each subject using a PCR-based technique. We observed a marginal association between 5-HT-2A variants and antidepressant response while MAOA genotypes were not associated. Possible stratification factors, such as sex, diagnosis, presence of psychotic features, HAMD scores at baseline, pindolol augmentation and SSRIs plasma levels did not significantly influence the observed results. The investigated MAOA and 5-HT-2A gene variants, therefore, do not seem to play a major role in SSRI antidepressant activity.  相似文献   
59.
Antiangiogenic and antitumor activity of IDN 5390, a new taxane derivative.   总被引:3,自引:0,他引:3  
PURPOSE: We previously reported that paclitaxel, a microtubule-stabilizing drug, inhibited angiogenesis, mainly by inhibiting endothelial cell motility (D. Belotti et al., Clin. Cancer Res., 2: 1843-1849, 1996). The aim of this study was to select a taxane with little cytotoxicity but with antimotility and hence antiangiogenic activity. EXPERIMENTAL DESIGN: Different taxanes, seco derivatives, and 14-beta-hydroxy-10-deacetyl baccatin III derivatives were tested for their effects on the proliferation and motility of human umbilical vein endothelial cells. The antiangiogenic and antineoplastic activities of the compound selected from this screening were further investigated in experimental models in vitro and in vivo. RESULTS: From the screening of different taxanes, we selected IDN 5390, a seco derivative that showed potent antimotility activity and less cytotoxicity than paclitaxel. In comparable experimental conditions, IDN 5390 inhibited endothelial cell migration without affecting proliferation. This compound dose-dependently inhibited the capacity of human umbilical vein endothelial cells plated on Matrigel to organize into a network of cords. In vivo, IDN 5390 significantly inhibited fibroblast growth factor-2-induced angiogenesis in Matrigel implants. Daily treatment with IDN 5390 in mice bearing established lung micrometastases from the B16BL6 murine melanoma caused a reduction in the size of metastases. Finally, IDN 5390 slowed the s.c. growth of the paclitaxel-resistant human ovarian carcinoma, 1A9/PTX22, xenografted in nude mice. CONCLUSIONS: The seco derivative IDN 5390 might represent the prototype of a new class of taxane derivatives with antiangiogenic properties.  相似文献   
60.
The influence of diet on human behaviour was first postulated several centuries ago, albeit in terms of a magical interpretation of life. Due to our improved knowledge of the basic science, we are now able to provide experimental proof to support this concept. Some opinions, which were once believed to be true, have now been disproved, whereas others have been reconfirmed in physiological terms. This paper aims to evaluate the state of the art in particular with regard to pediatrics. It is now certain that some amino-acids in the diet can influence brain activity by enhancing or reducing the metabolic rates of different neurotransmitters. A modulating effect on the brain has even been suggested with regard to some vitamins and minerals, but data on this aspect are still under evaluation. On the other hand, no data have yet been reported to support the hypothesis of a specific etiological role played by any nutrient in the development of behavioural disturbances.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号