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   16575篇
  免费   990篇
  国内免费   81篇
耳鼻咽喉   132篇
儿科学   425篇
妇产科学   418篇
基础医学   2617篇
口腔科学   662篇
临床医学   1375篇
内科学   3664篇
皮肤病学   341篇
神经病学   1961篇
特种医学   450篇
外科学   1455篇
综合类   41篇
一般理论   5篇
预防医学   1012篇
眼科学   274篇
药学   1349篇
中国医学   57篇
肿瘤学   1408篇
  2024年   18篇
  2023年   171篇
  2022年   394篇
  2021年   592篇
  2020年   360篇
  2019年   477篇
  2018年   574篇
  2017年   451篇
  2016年   522篇
  2015年   649篇
  2014年   738篇
  2013年   936篇
  2012年   1469篇
  2011年   1563篇
  2010年   775篇
  2009年   742篇
  2008年   1166篇
  2007年   1087篇
  2006年   1015篇
  2005年   925篇
  2004年   829篇
  2003年   753篇
  2002年   641篇
  2001年   75篇
  2000年   54篇
  1999年   69篇
  1998年   105篇
  1997年   94篇
  1996年   60篇
  1995年   57篇
  1994年   42篇
  1993年   30篇
  1992年   19篇
  1991年   16篇
  1990年   12篇
  1989年   23篇
  1988年   15篇
  1987年   22篇
  1986年   14篇
  1985年   14篇
  1984年   11篇
  1983年   15篇
  1982年   13篇
  1981年   12篇
  1980年   5篇
  1979年   5篇
  1978年   4篇
  1975年   3篇
  1973年   6篇
  1961年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
Angiogenesis in the human heart: Gene and cell therapy   总被引:3,自引:0,他引:3  
Tirziu D  Simons M 《Angiogenesis》2005,8(3):241-251
The concept of therapeutic angiogenesis – stimulation of new vessels growth to restore blood supply to ischemic tissue has been studied in a number of clinical trials in patients with advanced coronary and peripheral arterial disease. This review discusses the main biological processes underlying new vessel growth and addresses applications of growth factor and cell therapy based on the stimulation of angiogenesis. While still very young and controversial, cell therapy has an enormous potential that is yet to be explored. Multiple questions remain unanswered including the choice of the best cell type, patient selection and the mechanism of action. Nevertheless, much should be expected in this area in the next decade with the likely emergence of new therapies for treatment of ischemic diseases.  相似文献   
942.
943.
The aim of this study was to evaluate the performance of two different glass-ionomer cements: a high-density (Ketac Molar - ESPE) and a resin-modified cement (Fuji VIII - GC) using the Atraumatic Restorative Treatment technique to restore multisurface cavities in permanent teeth. A total of 60 ART restorations (30 with each material) were placed in schoolchildren (9-16 years of age) by two operators. After a period of 6 months, two independent examiners evaluated 59 restorations according to the criteria used in previous ART studies. Data were submitted to McNemar and Fischer tests. The success rate of the treatment was 98.3%. One restoration (Ketac Molar) was replaced by another material and was recorded as failure. The success rates of the restorations were 100% and 96.6% for Fuji VIII and Ketac Molar, respectively. There was no statistically significant difference in the restorations success between baseline and 6 months (p>0.05). In the same way, no significant differences were found between materials, cavity types or operators (p>0.05). The ART approach was highly appropriate and effective in restorations involving two or more tooth surfaces, after 6 months. The results showed a promising performance of the ART technique with both materials.  相似文献   
944.
945.
The principles of positron emission tomography (PET), recently introduced as a diagnostic procedure into the health sciences, are described. The principle clinical applications apply to a particular group of specialties: cardiology, neurology, psychiatry, and above all oncology. Positron emission tomography is a non-invasive diagnostic imaging technique with clinical applications. It is an excellent tool for the study of the stage and possible malignancy of tumors of head and neck, the detection of otherwise clinically indeterminate metastases and lymphadenopathies, and likewise for the diagnosis of relapses. The only tracer with any practical clinical application is fluor-desoxyglucosa-F18 (FDG). PET detects the intense accumulation of FDG produced in malignant tumors due to the increased glycolytic rate of the neoplastic cells. With the introduction of hybrid systems that combine computerized tomography or magnetic resonance with positron emission tomography, important advances are being made in the diagnosis and follow-up of oncologic pathology of head and neck.  相似文献   
946.
The chromosomal polymorphism of Anopheles funestus sensu stricto from Angola was analyzed from indoor-resting samples collected in 11 peri-urban and rural sites of the Luanda and Huambo Provinces, which are > 450 km apart and have distinct eco-climatic conditions. Five polymorphic paracentric inversions were observed (scored chromatids range = 202 to 248): 2Ra, 2Rh, 3Ra, 3Rb, and 3La. Inversions 3Rb and 3La were highly polymorphic; the 2Ra and 3Ra arrangements were absent in Luanda. No significant departures from Hardy-Weinberg and linkage equilibria were found at the locality, commune, or province level (sites 相似文献   
947.
Relative antiinflammatory and immunosuppressive potencies of glucocorticoids (GC) were previously well defined. Nonetheless, GC also regulate cell proliferation and programmed death (apoptosis). The aim of this study was to determine the relative potency of different GC on the modulation of cell survival. The GC-sensitive lymphoblast cell line CEM-c7/14 was submitted to 48 h-exposure to GC (dose-response curve from 10(-8) to 10(-5) M). Cell survival was analyzed employing the DimethylTiazol-Tetrazolium (MTT) test. For each GC at least 4 experiments were performed in quadruplicate. Responses to different GC at the same molarity were analyzed by ANOVA on Ranks. Cell responses to the same GC in different concentrations were tested by repeated measures ANOVA. The EC50 for each GC was calculated with the GraphPad Prism 3.0 software. The use of low concentrations (10(-8) and 10(-7) M) of hydrocortisone and methylprednisolone determined a similar effects on cell survival, which was less prominent than that observed with betamethasone, budesonide or momethasone. Momethasone was the most potent GC, inducing the most intense dexamethasone reduction on cell survival at the lowest concentration (10(-8) M). Momethasone and methylprednisolone were the two GC with the strongest impact on cell survival. Our findings suggest that antiproliferative and apoptotic potencies of GC are different from those previously reported antiinflammatory and immunosuppressive actions.  相似文献   
948.
949.
BACKGROUND: Diabetes mellitus is associated with pancreatic cancer in more than 80% of the cases. Clinical, epidemiological, and experimental data indicate that pancreatic cancer causes diabetes mellitus by releasing soluble mediators which interfere with both beta-cell function and liver and muscle glucose metabolism. METHODS: We analysed, by matrix-assisted laser desorption ionization time of flight (MALDI-TOF), a series of pancreatic cancer cell lines conditioned media, pancreatic cancer patients' peripheral and portal sera, comparing them with controls and chronic pancreatitis patients' sera. RESULTS: MALDI-TOF analysis of pancreatic cancer cells conditioned media and patients' sera indicated a low molecular weight peptide to be the putative pancreatic cancer-associated diabetogenic factor. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of tumor samples from diabetic and non-diabetic patients revealed the presence of a 1500 Da peptide only in diabetic patients. The amino acid sequence of this peptide corresponded to the N-terminal of an S-100 calcium binding protein, which was therefore suggested to be the pancreatic cancer-associated diabetogenic factor. CONCLUSIONS: We identified a tumor-derived peptide of 14 amino acids sharing a 100% homology with an S-100 calcium binding protein, which is probably the pancreatic cancer-associated diabetogenic factor.  相似文献   
950.
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