全文获取类型
收费全文 | 22134篇 |
免费 | 1296篇 |
国内免费 | 163篇 |
专业分类
耳鼻咽喉 | 252篇 |
儿科学 | 603篇 |
妇产科学 | 785篇 |
基础医学 | 2496篇 |
口腔科学 | 614篇 |
临床医学 | 1839篇 |
内科学 | 4381篇 |
皮肤病学 | 454篇 |
神经病学 | 1138篇 |
特种医学 | 779篇 |
外国民族医学 | 11篇 |
外科学 | 3714篇 |
综合类 | 358篇 |
现状与发展 | 2篇 |
一般理论 | 14篇 |
预防医学 | 2107篇 |
眼科学 | 637篇 |
药学 | 1943篇 |
中国医学 | 158篇 |
肿瘤学 | 1308篇 |
出版年
2023年 | 258篇 |
2022年 | 844篇 |
2021年 | 1294篇 |
2020年 | 704篇 |
2019年 | 909篇 |
2018年 | 1186篇 |
2017年 | 714篇 |
2016年 | 732篇 |
2015年 | 748篇 |
2014年 | 1067篇 |
2013年 | 1241篇 |
2012年 | 1789篇 |
2011年 | 1945篇 |
2010年 | 1104篇 |
2009年 | 821篇 |
2008年 | 1170篇 |
2007年 | 1149篇 |
2006年 | 1039篇 |
2005年 | 997篇 |
2004年 | 854篇 |
2003年 | 755篇 |
2002年 | 681篇 |
2001年 | 148篇 |
2000年 | 117篇 |
1999年 | 100篇 |
1998年 | 90篇 |
1997年 | 89篇 |
1996年 | 80篇 |
1995年 | 71篇 |
1994年 | 66篇 |
1993年 | 55篇 |
1992年 | 53篇 |
1991年 | 56篇 |
1990年 | 55篇 |
1989年 | 53篇 |
1988年 | 51篇 |
1987年 | 51篇 |
1986年 | 39篇 |
1985年 | 39篇 |
1984年 | 45篇 |
1983年 | 39篇 |
1982年 | 36篇 |
1981年 | 26篇 |
1980年 | 21篇 |
1978年 | 16篇 |
1977年 | 15篇 |
1976年 | 20篇 |
1974年 | 16篇 |
1973年 | 19篇 |
1966年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Tarek Mohamed A. Saoud Ashraf Zaazou Ahmed Nabil Sybel Moussa Louis M. Lin Jennifer L. Gibbs 《Journal of endodontics》2014
Introduction
Revascularization treatment is rapidly becoming an accepted treatment alternative for the management of endodontic pathology in immature permanent teeth with necrotic dental pulps. However, the success and timing of clinical resolution of symptoms, and radiographic outcomes of interest, such as continued hard tissue deposition within the root, are largely unknown.Methods
In this prospective cohort study, 20 teeth were treated with a standardized revascularization treatment protocol and monitored for clinical and radiographic changes for 1 year. Standardized radiographs were collected at regular intervals, and radiographic changes were quantified.Results
All 20 treated teeth survived during the 12-month follow-up period, and all 20 also met the clinical criteria for success at 12 months. As a group, the treated teeth showed a statistically significant increase in radiographic root width and length and a decrease in apical diameter, although the changes in many cases were quite small (such that the clinical significance is unclear). The within-case percent change in apical diameter after 3 months was 16% and had increased to 79% by 12 months, with 55% (11/20) showing complete apical closure. The within-case percent change in root length averaged less than 1% at 3 months and increased to 5% at 12 months. The within-case percent change in root thickness averaged 3% at 3 months and 21% at 12 months.Conclusions
Although clinical success was highly predictable with this procedure, clinically meaningful radiographic root thickening and lengthening are less predictable after 1-year of follow-up. Apical closure is the most consistent radiographic finding. 相似文献993.
Fadwa Al-Ghalib Al-Sharif Osama Hussien Al-Jiffri Shehab Mahmoud Abd El-Kader Eman Mohamed Ashmawy 《African health sciences》2014,14(1):11-16
Background
Patients with hemophilia A have low bone density than healthy controls. It is now widely recognized that physical activity and sports are beneficial for patients with hemophilia.Objective
To compare the effects of mild and moderate intensity treadmill walking exercises on markers of bone metabolism and hand grip strength in male patients with moderate hemophilia A.Material and Methods
Fifty male patients with moderate hemophilia, and age range from 25 to 45 years. The subjects were randomly assigned into 2 equal groups; the first group (A) received moderate intensity aerobic exercise training. The second group (B) received mild intensity aerobic exercise training.Results
There was a 32.1% and 24.8% increase in mean values of serum calcium and hand grip strength respectively and 22.7 % reduction in mean values of parathyroid hormone in moderate exercise training group (A). While there was a 15.1 % and 15 % increase in mean values of Serum Calcium and Hand grip strength respectively and 10.3 % reduction in mean values of parathyroid hormone in mild exercise training group(B). The mean values of serum calcium and hand grip strength were significantly increased, while the mean values of parathyroid hormone were significantly decreased in both groups . There were significant differences between mean levels of the investigated parameters in group (A) and group (B) after treatment.Conclusion
Moderate intensity aerobic exercise training on treadmill is appropriate to improve markers of bone metabolism and hand grip strength in male patients with hemophilia A. 相似文献994.
Matthias Wiens Tarek A. Elkhooly Heinz-Christoph Schröder Tawheed H.A. Mohamed Werner E.G. Müller 《Acta biomaterialia》2014,10(10):4456-4464
Several attempts have been made in the past to fabricate hybrid materials that display the complementary properties of the polyester polycaprolactone (PCL) and the polysaccharide chitosan (CHS) for application in the field of bone regeneration and tissue engineering. However, such composites generally have no osteogenic activity per se. Here we report the synthesis of a chitosan-graft-polycaprolactone (CHS-g-PCL) and its subsequent characterization, including crystallinity, chemical structure and thermal stability. Upon surface-functionalization of CHS-g-PCL with osteogenic biosilica via the surface-immobilized enzyme silicatein, protein adsorption, surface morphology and wettability were assessed. Finally, the cultivation of osteoblastic SaOS-2 cells on the surface-functionalized CHS-g-PCL was followed by analyses of cell viability, mineral deposition and alkaline phosphatase activity. These characterizations revealed a composite that combines the versatile properties of CHS-g-PCL with the osteogenic activity of the silicatein/biosilica coating and, hence, represents an innovative alternative to conventionally used CHS/PCL composites for biomedical applications, where stable bone–material interfaces are required. 相似文献
995.
Manu Tomar Raghavendra Prahlad Rao Palaniyamma Dorairaj Abhishek Koshta Sowbhagya Suresh Mohamed Rafiq Rajesh Kumawat Rangesh Paramesh Babu U. V K.
V. Venkatesh 《RSC advances》2019,9(32):18578
Hydroxycitric acid (HCA), a major active ingredient of Garcinia cambogia extracts, is known to suppress body weight gain and fat synthesis in animals and humans. But the underlying mechanism of HCA action is not fully understood. Clinical study on 100 obese individuals for a period of 3 months was performed followed by a computational study aimed to investigate the effects of HCA treatment on human subjects at anthropometric and plasma lipid profile levels. A detailed hepatic metabolic model was used to incorporate the effect of HCA at the metabolic pathway level. Perturbation analysis of ATP citrate lyase activity in the metabolic pathway was performed to simulate the net effect of HCA. Significant reductions in body weight, triceps, subscapular, and mid axillary measurements as well as in serum triglyceride, cholesterol, HDL and LDL levels were observed following HCA dosage. During the study, half of the subjects experienced a decline in body weight and the remainder experienced an increase in body weight. However, analysis of fat mass with the help of empirical correlations clearly showed significant reduction in the mean values due to HCA dosage in both cases. An extra increase in fat free mass was responsible for offsetting the decrease in fat mass for the subjects who experienced an increase in body weight during the trials. Perturbation analysis showed a net reduction in fatty acid, triglyceride and cholesterol synthesis along with urea cycle fluxes under lipogenetic conditions. Moreover, protein synthesis fluxes increased under these conditions. These results indicate that HCA treatment can reduce body weight gain and fat accumulation in obese subjects along with improving their anthropometric parameters and metabolic state.Hydroxycitric acid (HCA), a major active ingredient of Garcinia cambogia extracts, is known to suppress body weight gain and fat synthesis in animals and humans. 相似文献
996.
997.
998.
999.
1000.
Mohamed H. Hekal Abeer M. El-Naggar Fatma S. M. Abu El-Azm Wael M. El-Sayed 《RSC advances》2020,10(7):3675
Background and aim: The current study reports the synthesis and biological evaluation of two novel series of 4-(5-mercapto-1,3,4-oxadiazol-2-yl)phthalazin-1(2H)-one derivatives. Methods: The synthetic reactions were carried out under both conventional and ultrasonic irradiation conditions. The anti-proliferative activity of the newly synthesized compounds against two human epithelial cell lines; liver (HepG2) and breast (MCF-7) in addition to normal fibroblasts (WI-38) was investigated. In addition to molecular docking studies, the possible mechanism(s) of action were also explored. Results: In general, an improvement in synthetic rates and yields was observed when reactions were carried out under sonication compared with classical conditions. The structures of the products were established based on analytical and spectral data. Derivatives 2e and 7d, in addition to compound 1, had significant and selective anti-proliferative activity against liver and breast cancer cell lines without harming normal fibroblasts. These derivatives arrested the cell cycle progression and/or induced apoptosis. This has been manifested by the elevation in the expression of p53 and caspase 3, down-regulation of cdk1, and a reduction in the concentrations of MAPK and Topo II at submicromolar concentrations. The latter results confirmed the molecular docking study. Conclusions: Compound 1 had the best profile on the gene and protein levels (arresting cell cycle and inducing apoptosis). The ability of compounds 1 and 2e to inhibit both MAPK and Topo II nominates these derivatives as potential candidates for further anticancer and antitumor studies.The current study reports the synthesis and biological evaluation of two novel series of 4-(5-mercapto-1,3,4-oxadiazol-2-yl)phthalazin-1(2H)-one derivatives. 相似文献