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   3024篇
  免费   187篇
  国内免费   14篇
耳鼻咽喉   16篇
儿科学   49篇
妇产科学   29篇
基础医学   402篇
口腔科学   58篇
临床医学   250篇
内科学   759篇
皮肤病学   85篇
神经病学   378篇
特种医学   85篇
外科学   508篇
综合类   11篇
一般理论   1篇
预防医学   92篇
眼科学   33篇
药学   176篇
中国医学   10篇
肿瘤学   283篇
  2023年   27篇
  2022年   39篇
  2021年   93篇
  2020年   47篇
  2019年   58篇
  2018年   59篇
  2017年   57篇
  2016年   69篇
  2015年   74篇
  2014年   95篇
  2013年   94篇
  2012年   136篇
  2011年   163篇
  2010年   88篇
  2009年   81篇
  2008年   159篇
  2007年   139篇
  2006年   115篇
  2005年   102篇
  2004年   119篇
  2003年   136篇
  2002年   129篇
  2001年   65篇
  2000年   60篇
  1999年   80篇
  1998年   38篇
  1997年   27篇
  1996年   33篇
  1992年   47篇
  1991年   62篇
  1990年   60篇
  1989年   54篇
  1988年   42篇
  1987年   62篇
  1986年   30篇
  1985年   31篇
  1984年   25篇
  1983年   20篇
  1980年   20篇
  1979年   28篇
  1978年   23篇
  1977年   21篇
  1975年   21篇
  1974年   23篇
  1972年   28篇
  1971年   18篇
  1970年   20篇
  1969年   32篇
  1967年   18篇
  1966年   21篇
排序方式: 共有3225条查询结果,搜索用时 31 毫秒
1.
Finasteride is standard medical treatment for androgenetic alopecia; however, no large studies with 5 years or more of follow up have been performed in Japan. The authors followed Japanese men with androgenetic alopecia treated with finasteride for 5 years to evaluate long‐term treatment efficacy. Of 903 men treated with finasteride (1 mg/day), 801 patients were evaluated over 5 years by modified global photographic assessment. Although the proportion of improvement was high (99.4%), modified global photographic assessment scores after 5 years of treatment were lower in patients with more advanced disease as measured by the modified Norwood–Hamilton scale. After separating patients into “sufficient” and “insufficient” efficacy groups according to the modified global photographic assessment score after 5 years (scores ≥6 and <6, respectively), multivariate analysis showed that independent risk factors of insufficient efficacy were age at start of treatment of 40 years or more (P = 0.021) and classification on the modified Norwood–Hamilton scale (P < 0.001), whereas presence of stress at start of treatment was a negative predictor (P = 0.025). In conclusion, continuous finasteride treatment for 5 years improved androgenetic alopecia with sustained effect among Japanese. Younger age and less advanced disease at start of treatment were the key predictors of higher finasteride efficacy.  相似文献   
2.
3.
4.
5.
Micro-shear bond strength of dual-cured resin cement to glass ceramics.   总被引:4,自引:0,他引:4  
OBJECTIVES: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-cured resin cement to bond to glass ceramics designed for in indirect adhesive restoration. METHODS: A cast glass ceramic (Olympus Castable Ceramics) with a crystalline phase consisting of mica and beta-spondumene was selected as the substrate material. The glass surfaces, which were sandblasted, polished, or etched with phosphoric acid or hydrofluoric acid (HF), were bonded with a dual-cured resin cement (Panavia Fluoro Cement) using a dentin adhesive system (Clearfil SE Bond), both with and without a silane coupling agent. A micro-shear bond test was carried out to measure the bond strength of the resin cement to the glass surface. Each glass surface was bonded and tested using the shear test. In addition, surfaces with the bonding removed after the shear bond test, the adhesive interface between the glass and cement, and an etched glass surface without any bonding, were studied morphologically using scanning electron microscopy or field emission scanning electron microscopy. RESULTS: Usage of a silane coupling agent effectively raised the bond-strength values of resin cement (Fisher's PLSD, P<0.01). The effectiveness of using phosphoric acid etching to improve bonding was not clear (Fisher's PLSD, P>0.01). HF-etching for 30s seemed to over-etch the glass surface, resulting in adverse effects on bonding (Fisher's PLSD, P<0.01). SIGNIFICANCE: The micro-shear bond strength between Olympus Castable Ceramics and resin cement can be increased by the silane coupling agent used along with an acidic primer.  相似文献   
6.
H Satomi  K Takahashi  I Kosaka  M Aoki 《Brain research》1989,492(1-2):255-260
The precise course and termination levels of the corticospinal tract (CST) in the cat were studied using the anterograde transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). Following injection of WGA-HRP into the pericruciate (sensorimotor) cortex on one side, we observed the precise caudal termination levels of the CST fibers in the lateral and ventral funiculi. Simultaneously, the bilateral CSTs descending through the dorsal funiculus of the spinal cord were identified. Anterogradely labeled CST fibers within the lateral and ventral funiculi were observed bilaterally to reach the level of the third sacral (S3) spinal segment, which is lower than that ever described. The lowest level of the CST fibers within the dorsal funiculus, however, reached the level of the first sacral (S1) spinal segment. In conclusion, this study demonstrates that, in the cat, there exist 6 different CSTs (crossed and uncrossed lateral, ventral, dorsal) and that the termination levels of the lateral and ventral CSTs are much lower than those described in previous reports.  相似文献   
7.
Two cases of vasovagal syncope (VVS) during venous access are reported. Both patients had a history of fainting episodes and experienced bradycardia with asystole, hypotension, and fainting. Pain and phobic stress during venous access triggered an increase in parasympathetic tone, resulting in bradycardia with asystole and hypotension in both cases. Hypotension and bradycardia likely caused cerebral hypoperfusion, leading to fainting. The intense parasympathetic tone triggered by somatic or emotional stress was likely responsible for directly depressing the sinus node, leading to asystole and bradycardia. Bradycardia with asystole progressing to syncope is a potentially fatal dysrhythmia in patients with cardiovascular disease or older patients with decreased cardiac function. Appropriate treatment for VVS includes the administration of intravenous fluids, vagolytics, ephedrine, and the rapid use of the Trendelenburg position. Intravenous fluids and atropine were used to treat the present patients.  相似文献   
8.
Metabolism of 99mTc-ethyl cysteinate dimer (99mTc-ECD) in blood was studied mainly in vitro. When 99mTc-ECD was mixed with blood taken from 12 subjects, the octanol extraction ratio of ECD (y) decreased rapidly and the octanol extraction ratio-time profile well fitted a monoexponential curve (y = Ae-kt/1000, A, k: constant, t: time after mixing). The k value and hematocrit (Ht) were significantly correlated (k = 0.376Ht-3.27, r = 0.897, p less than 0.001), therefore, it was suggested that the majority of the enzyme which dissolves ECD exists in red blood cells. When ECD was mixed with blood, there were more hydrophilic products of ECD in plasma than those generated by the enzyme in plasma. In vivo input function of 99mTc-ECD was calculated by arterial blood sampling and octanol extraction. The duration of effective input was relatively short, which was attributed to rapid decrease of octanol extraction ratio in vivo.  相似文献   
9.
Two patients with diabetes mellitus had persistent hypouricemia due to increased urate clearance; the degree of the apparent renal hypouricemia with uricosuria was quite mild. At the onset of diabetes, their serum urate levels were normal. Even after good diabetes control in both cases, hypouricemia continued. Based on the pharmacological evaluation in both patients, pyrazinamide administration could partially decrease urate clearance, however, suppression by pyrazinamide was less than in normal subjects, and probenecid increased urate clearance. These results suggest that the present cases had a renal abnormality affecting tubular presecretory reabsorption of urate, which might be due to diabetes mellitus.  相似文献   
10.
A 75-year-old man was admitted to our hospital with the chief complaint of a choking feeling around the esophagus. Laboratory examinations revealed eosinophilia, and high levels of serum immunoglobulin (Ig) E. A computed tomography scan (CT) showed wall thickening of the esophagus and terminal ileum, and ascites around the liver. An endoscopic examination revealed mild mucosal edema in the esophagus, stomach, and small intestine. Biopsy specimens showed diffuse eosinophilic infiltration in the mucosa. We therefore diagnosed eosinophilic gastroenteritis. Oral prednisolone relieved clinical conditions and the CT image improved. This case was considered valuable, because there have been few reports of eosinophilic esophagitis in Japan.  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