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   5466篇
  免费   231篇
  国内免费   23篇
耳鼻咽喉   17篇
儿科学   106篇
妇产科学   105篇
基础医学   674篇
口腔科学   61篇
临床医学   316篇
内科学   1382篇
皮肤病学   171篇
神经病学   428篇
特种医学   131篇
外科学   1006篇
综合类   19篇
一般理论   1篇
预防医学   90篇
眼科学   41篇
药学   261篇
中国医学   18篇
肿瘤学   893篇
  2023年   52篇
  2022年   80篇
  2021年   113篇
  2020年   80篇
  2019年   86篇
  2018年   96篇
  2017年   88篇
  2016年   113篇
  2015年   108篇
  2014年   147篇
  2013年   198篇
  2012年   287篇
  2011年   412篇
  2010年   217篇
  2009年   172篇
  2008年   360篇
  2007年   390篇
  2006年   323篇
  2005年   387篇
  2004年   380篇
  2003年   350篇
  2002年   313篇
  2001年   42篇
  2000年   49篇
  1999年   80篇
  1998年   95篇
  1997年   85篇
  1996年   88篇
  1995年   76篇
  1994年   73篇
  1993年   45篇
  1992年   39篇
  1991年   39篇
  1990年   27篇
  1989年   20篇
  1988年   26篇
  1987年   14篇
  1986年   14篇
  1985年   12篇
  1984年   14篇
  1983年   7篇
  1982年   7篇
  1981年   13篇
  1980年   22篇
  1979年   8篇
  1978年   14篇
  1977年   13篇
  1976年   6篇
  1975年   11篇
  1973年   6篇
排序方式: 共有5720条查询结果,搜索用时 13 毫秒
101.
Background:   Osteoporosis is believed to result from the interaction among multiple environmental and genetic determinants that regulate bone-mineral density (BMD).
Methods:   To investigate a potentially predisposing genetic factor in the onset of osteoporosis, we looked for a possible association between BMD in adult Japanese women and known polymorphisms in the leukemia inhibitory factor receptor gene (LIFR).
Results:   An association analysis of chromosomes from 384 volunteer subjects revealed significant correlation between the −603T > C variant of LIFR and radial BMD ( r  = 0.11, P  = 0.032) in this test population. Comparisons of mean values of adjusted radial BMD among separate genotypic groups implied an allelic dosage effect, because homozygous carriers of T alleles of that SNP had the highest adjusted BMDs (0.403 ± 0.054 g/cm2); women homozygous for the C-allele had the lowest (0.373 ± 0.042 g/cm2), and heterozygous individuals had intermediate scores (0.394 ± 0.056 g/cm2).
Conclusion:   This polymorphism in LIFR may be an important determinant of predisposition to postmenopausal osteoporosis.  相似文献   
102.
103.
104.
Usually, benign tumors are not associated with an increased F-18 fluorodeoxyglucose (F-18 FDG) uptake on positron emission tomography (PET), although some exceptions have been reported in adrenal neoplasms. We present a rare case of adrenocortical oncocytoma associated with markedly increased FDG uptake, demonstrating a maximum standardized uptake value of 46.8. Histological examination demonstrated diffuse proliferation of tumor cells with eosinophilic and granular cytoplasm that were diffusely immunopositive for mitochondria and glucose transport protein 1, with focal and weak immunopositivity for 3β-hydroxysteroid dehydrogenase. Ultrastructural examination also revealed abundant mitochondria in the tumor cells. The tumor was diagnosed as adrenocortical oncocytoma and was considered benign according to Lin-Weiss-Bisceglia criteria. Diagnosis of adrenocortical oncocytoma can pose difficulties during both preoperative radiological and postoperative histopathological investigations.  相似文献   
105.
106.
107.
108.
We evaluated the pharmacokinetics of linezolid in the case of an obese Japanese patient (body weight 116 kg; body mass index 37 kg/m(2)). Linezolid was administered at a dose of 600 mg by intravenous drip infusion for 60-90 min at 12-h intervals. The results showed increased clearance of linezolid and a reduced serum concentration compared to population pharmacokinetic parameters, with trough levels below the 90% minimum inhibitory concentration. However, linezolid was effective for improving lung infection and inflammation in our patient, which may be due to its particularly effective transfer into lung tissues. Linezolid undergoes slow non-enzymatic oxidation in vivo that may be increased in obese patients, and this may account for the greater clearance. Our findings are useful for the planning of linezolid therapy in obese patients.  相似文献   
109.
Podoplanin, a transmembrane sialomucin-like glycoprotein, is a specific marker of lymphatic vessels, and its expression is also considered to be associated with tumor invasion and tooth development. In this study, we examined the expression of podoplanin in calcifying cystic odontogenic tumor (CCOT) in comparison with that in other so-called hard α-keratin-expressing tumors such as craniopharyngioma (CP) and pilomatrixoma (PM). Immunohistochemical staining for podoplanin was carried out using surgical specimens of 15 CCOTs of the jaw, 19 CPs of the pituitary gland, and 15 PMs of the skin. Positivity for hard α-keratin was evident in ghost, shadow and transitional cells in all of these tumors (100%). The podoplanin expression in CCOTs was evident in the periphery of ameloblastoma-like epithelium (86.6%) and the epithelial cells adjacent to ghost cells (60%). On the other hand, in adamantinomatous-type CPs, podoplanin expression was observed in epithelial components corresponding to the stratum intermedium (100%), but not in the periphery of ameloblastoma-like epithelium (0%). In squamous-type CPs podoplanin was expressed in basal cells (100%), but all of the PMs were podoplanin-negative (0%). In the periphery of the ameloblastoma-like epithelium or basophilic cell layer, podoplanin was expressed more strongly in CCOTs than in CPs or PMs. These findings suggest that the expression of podoplanin in CCOTs may reflect rapid turnover of cytoskeletal filaments and local invasiveness.  相似文献   
110.
The aim of this study was to prospectively measure liver stiffness with real-time tissue elastography in patients with nonalcoholic fatty liver diseases (NAFLD) and to compare the result with the clinical assessment of fibrosis using histological stage. One hundred and eighty-one prospectively enrolled patients underwent real-time tissue elastography, with the first 106 being analyzed as the training set and the remaining 75 being evaluated as the validation set. Hepatic and splenic elastic ratios were calculated and compared with stage of histological fibrosis. Portal hypertension (PH) was assessed. Real-time tissue elastography cut-off values by stage in the training set were 2.47 for F1, 2.67 for F2, 3.02 for F3, and 3.36 for F4. Using these cut-off values, the diagnostic accuracy of hepatic fibrosis in the validation set was 82.6%-96.0% in all stages. Only portal fibrosis correlated with the hepatic elastic ratio by multivariate analysis. The area under the receiver operating characteristic curve of elastic ratio better correlated than serum fibrosis markers in both early and advanced fibrosis stages. Patients with PH, defined by splenic elasticity, had early fibrosis. Patients with severe PH were found only in the group with cirrhosis. Conclusion: Real-time tissue elastography is useful in evaluating hepatic fibrosis and PH in patients with NAFLD. (HEPATOLOGY 2012).  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