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   2784篇
  免费   152篇
  国内免费   8篇
耳鼻咽喉   24篇
儿科学   24篇
妇产科学   13篇
基础医学   362篇
口腔科学   72篇
临床医学   163篇
内科学   675篇
皮肤病学   50篇
神经病学   181篇
特种医学   153篇
外科学   562篇
综合类   9篇
预防医学   81篇
眼科学   44篇
药学   203篇
中国医学   3篇
肿瘤学   325篇
  2023年   19篇
  2022年   41篇
  2021年   62篇
  2020年   34篇
  2019年   45篇
  2018年   63篇
  2017年   58篇
  2016年   63篇
  2015年   50篇
  2014年   79篇
  2013年   92篇
  2012年   150篇
  2011年   173篇
  2010年   101篇
  2009年   88篇
  2008年   127篇
  2007年   141篇
  2006年   147篇
  2005年   135篇
  2004年   145篇
  2003年   105篇
  2002年   103篇
  2001年   75篇
  2000年   79篇
  1999年   72篇
  1998年   39篇
  1997年   33篇
  1996年   23篇
  1995年   24篇
  1994年   19篇
  1993年   25篇
  1992年   71篇
  1991年   49篇
  1990年   67篇
  1989年   39篇
  1988年   32篇
  1987年   29篇
  1986年   43篇
  1985年   33篇
  1984年   24篇
  1983年   25篇
  1982年   7篇
  1980年   11篇
  1979年   18篇
  1977年   9篇
  1975年   6篇
  1972年   11篇
  1971年   8篇
  1970年   10篇
  1967年   5篇
排序方式: 共有2944条查询结果,搜索用时 15 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.
An attempt was made to explore the quantitative relationship between the intestinal absorption data obtained from in vivo studies and in situ perfusion studies. The time course of the fraction remaining to be absorbed of L-glucose, erythritol, and urea in the small intestine following the intrajejunal administration to rats was described by a one-compartment model. Thus derived first-order intestinal absorption rate constants (ka) obtained from the in vivo studies in rats were compared with the membrane permeability clearances (CLa,m) estimated in a single-pass perfusion system. Not only were ka and CLa,m in the same increasing order of L-glucose less than erythritol less than urea, but also the operational luminal volumes given as CLa,m/ka were in agreement with the in vivo luminal volume of jejunum estimated by an inulin dilution method. This result suggests that the in vivo intestinal absorption rate (or ka) can be correlated with the intestinal membrane permeability (or CLa,m) by taking the in vivo luminal volume into account.  相似文献   
3.
Objectives To analyze the relationship between lateral displacement of the mandible and scoliosis. Methods From April 2002 through July 2003, we examined posteroanterior cephalometric radiographs and chest X-rays from 85 patients with jaw deformities and a control group of 20 patients with no jaw deformities. To measure the lateral shift of the mandible, we drew a horizontal baseline (X axis) on the cephalogram connecting the intersection of the external margins of the orbits and the most lateral points of the greater wings of the sphenoid. A vertical baseline (Y axis) was then marked perpendicular to the X axis, intersecting the ethmoid crista galli. Then, we measured the lateral displacement of the mandibular mentum from the Y axis. Displacement to the right was designated positive; that to the left was designated negative. Cobb's method was used to measure scoliosis curves on chest X-rays; the direction of the curve was designated similarly. Results Of the 85 patients with jaw deformity, 23 (27.1%) had a Cobb angle exceeding 10°. None of the control group had scoliosis exceeding 10°. No correlation was found between the direction of mandibular displacement and the direction of scoliosis. Conclusion This study suggests a relationship between jaw deformities and scoliosis, as scoliosis was found in 27.1% of the patients with a main complaint of jaw deformity.  相似文献   
4.
In this study, we used a novel 4-fluid nozzle spray drier to prepare composite microparticles of a water-insoluble drug, flurbiprofen (FP), and a water-soluble drug, sodium salicylate (SS), for the purpose of improving the water solubility of FP. An ethanol solution of FP and an aqueous SS solution were simultaneously introduced through different liquid passages in the 4-fluid nozzle spray drier and then spray-dried. Quantitative elemental analysis suggested that the FP/SS ratio in each composite microparticle was nearly the same as the formulation ratio. We also found that SS and FP exist in a low crystallinity state in the composite particles. Release of FP from dissolved composite microparticles was markedly improved because of an increase in the effective surface area following rapid dissolution of SS. This study shows that it is possible to prepare FP-SS composite microparticles using a 4-fluid nozzle spray drier in single process and that this can improve the ability of FP to dissolve in water.  相似文献   
5.
6.
BACKGROUND: Although selective serotonin reuptake inhibitors (SSRIs) are the mainstay of pharmacological treatment for obsessive-compulsive disorder (OCD), some OCD patients do not show improvement. Sometimes, the addition of a low-dose atypical antipsychotic, such as risperidone, or olanzapine, to ongoing SSRI treatment has been shown to be effective. However, there are patients who still show no response after trials with this augmentation therapy. In the present study, we examined the clinical features of OCD patients who showed different responses to pharmacological treatment. SUBJECTS AND METHOD: Fifty OCD patients were divided into three groups according to their pharmacological responses: responders to SSRI (group A: n= 25), responders to SSRI with an atypical antipsychotic (group B: n= 15), and non-responders to both SSRI and SSRI with an atypical antipsychotic (group C: n= 10). We examined the clinical features such as age, sex, age of onset, duration of illness, types of obsessive-compulsive symptoms, severity, improvement after treatment, insight into disease, depression, comorbidity, involving family members in compulsive or ritualistic behavior, and the level of social adaptation of each OCD group. RESULTS: Twenty five patients showed a good response to SSRI monotherapy, 15 showed a response to antipsychotic augmentation, and 10 were non-responders to both SSRI and SSRI with an atypical antipsychotic. Significantly lower insight levels were observed only in group B and higher depressive levels in group C. OCD patients who were refractory to SSRI monotherapy showed comorbidity at a significantly higher frequency. OCD patients in group A showed significantly greater improvement, and group B showed inferior social adaptation after treatment. There were no significant differences in age, sex, age of onset, duration of illness, severity, involving family members in compulsive or ritualistic behavior, and social adaptation before treatment in the three OCD groups. CONCLUSION: There were differences in the clinical features of OCD patients who showed different responses to pharmacological treatment. Our results suggest that OCD is clinically and biologically heterogeneous. It may be important to divide OCD patients into subgroups for future studies.  相似文献   
7.
Objectives To develop a simple image viewer that utilizes image files in general-purpose formats that are written from the original 3DX volume data. Methods We used FLASH MX2004 for Macintosh to develop a simple image viewer. In developing the software for the simple image viewer, we decided that the viewer should provide the following features: (1) be available to both Windows OS and Mac OS, (2) allow interlocking of the 3D images, (3) display image enlargement, and (4) allow distance measurements. The accuracy of the distance measurements was evaluated. Results The procedure was as follows: (1) write 3D images in jpeg format to a folder on i-VIEW; (2) place the folder containing the 3D images into the directory of the simple image viewer software on a PC; (3) start the software and open the window to input the folder name containing the 3D images; and (4) display the 3D images. Our viewer had features such as image enlargement, interlocking 3D images, drawing, and distance measurements. No significant differences were shown between the measurements made by our simple viewer and the actual values of the images in any direction. Conclusions Our image-viewing software for 3DX is beneficial for clinical use.  相似文献   
8.
9.
The effects of ageing on the oral (gastrointestinal) absorption of d -xylose were investigated by analysing the gastrointestinal disposition after oral administration to young (9 weeks) and old (53 weeks) rats. A linear model assuming first-order gastric emptying followed by first-order intestinal absorption was fitted to remaining fraction vs time profiles for the stomach and small intestine to estimate the gastric emptying rate constant (kg) and the intestinal absorption rate constant (ka). In young and old rats, kg values were 0·087 ± 0·008 and 0·070 ± 0·007 min?1, respectively, and ka values were 0·020 ± 0·002 and 0·018 ± 0·002 min?1 suggesting an insignificant effect on ageing on the rate of oral absorption. The average intestinal lumen volume (Vav) was unchanged with ageing, and so was the apparent intestinal membrane permeability clearance (CLapp) as the product of ka and Vav. However, the small intestinal transit time (Tsi) was suggested to be twice that in older rats (171 min) than in young rats (78 min) by the analysis of gastrointestinal disposition of inulin, a non-absorbable marker. It was also shown that our preceding finding of an increase in the fraction absorbed of D-xylose with ageing can be solely ascribable to the delay in intestinal transit. Thus, among various determinants of oral absorption, only Tsi was found to be altered with ageing. The CLa,app and ka of passively absorbed drugs such as D-xylose may be generally unchanged, and the fraction absorbed may increase with ageing by the delay in intestinal transit.  相似文献   
10.
The purification of 45 KDa EMBP and the production of monospecific anti-serum is described. 45 KDa EMBP was purified by relatively simple methods using ion exchange HPLC (TSK-GEL DEAE-5PW column) and size exclusion HPLC (TSK-GEL G3000SW column). The results clearly demonstrated the speed and simplicity of the method using these columns, compared to previously-described methods for purification of 45 KDa EMBP.  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