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   31021篇
  免费   2507篇
  国内免费   334篇
耳鼻咽喉   109篇
儿科学   103篇
妇产科学   103篇
基础医学   2606篇
口腔科学   14497篇
临床医学   2949篇
内科学   1007篇
皮肤病学   358篇
神经病学   507篇
特种医学   242篇
外科学   783篇
综合类   4478篇
现状与发展   1篇
一般理论   2篇
预防医学   4420篇
眼科学   107篇
药学   1091篇
  137篇
中国医学   247篇
肿瘤学   115篇
  2024年   62篇
  2023年   729篇
  2022年   839篇
  2021年   1273篇
  2020年   1324篇
  2019年   1217篇
  2018年   1065篇
  2017年   1206篇
  2016年   1296篇
  2015年   1163篇
  2014年   2114篇
  2013年   2234篇
  2012年   1973篇
  2011年   1965篇
  2010年   1527篇
  2009年   1471篇
  2008年   1519篇
  2007年   1521篇
  2006年   1243篇
  2005年   959篇
  2004年   789篇
  2003年   672篇
  2002年   568篇
  2001年   475篇
  2000年   389篇
  1999年   305篇
  1998年   298篇
  1997年   318篇
  1996年   300篇
  1995年   245篇
  1994年   205篇
  1993年   204篇
  1992年   244篇
  1991年   199篇
  1990年   175篇
  1989年   182篇
  1988年   197篇
  1987年   157篇
  1986年   139篇
  1985年   147篇
  1984年   108篇
  1983年   100篇
  1982年   89篇
  1981年   87篇
  1980年   100篇
  1979年   86篇
  1978年   69篇
  1977年   82篇
  1976年   68篇
  1974年   66篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Abstract A single blind 30 day study compared the reduction of plaque and gingivitis for the Hapika® Powerbrush to the Interplak® ultra 10 tuft. A longitudinal parallel group design was utilized and screening evaluation was performed to determine patient eligibility prior to study enrollment. 66 subjects were entered into the study and assigned to 1 of 2 groups, each using one of the toothbrushes. At baseline, subjects received an oral soft tissue exam, a dental hard tissue exam, and were scored by the Lobene modification of the Löe and Silness gingival index (GI). Plaque was then disclosed and scored both pre and post brushing using the modified Turesky plaque/debris examination and an interproximal bleeding examination was performed post-brushing. On days 15 and 30, after an oral soft tissue and GI examination, plaque was graded by the Modified Turesky plaque/debris exam. Subjects then brushed and were graded by the Modified Turesky plaque/debris examination and an interproximal bleeding index examination. The results showed that both brushes provided a similar change in clinical indices. All produced a statistically significant reduction from baseline to day 30 for the gingival index (26.5-29.1%), the bleeding index (13.8-24.1%), and the plaque index (16.9-19.4%), A comparison of pre and post brushing scores for the plaque index at 30 showed that both brushes reduced plaque similarly with a statistically significant reduction (P<0.05) from their pre-brushing plaque index scores at all time periods.  相似文献   
92.
93.
A complete annual entry of 181 students were administered a questionnaire in which they were invited to make value judgements about all aspects of their 3-month course in obstetrics and gynaecology. The resulting performance indicators were used to compare individual staff and clinical firms.  相似文献   
94.
误种卡介苗引起小学生癔病流行的调查(附34例报告)   总被引:1,自引:0,他引:1  
本文报告了秦皇岛市山海关区某村小学生,1995年11月23日因误种卡介苗发生癔病流行的症状、预后及处理经过。对误种卡介苗的学生处理不当,在促进症状发生和发展中起决定作用。据此提出了今后防治的建议。  相似文献   
95.
大学生心理障碍干预实验研究   总被引:2,自引:0,他引:2  
目的 探索有效的心理障碍治疗方法 ,降低大学生心理障碍发病率。方法 以经SCL - 90测试分析筛检出≥ 2项因子分在 2 3以上的心理障碍者 2 0 5人为研究对象 ,采取心理治疗、中药治疗、中药与心理疗法结合治疗 3种干预模式对实验组心理障碍者进行为期半年治疗 ,对实验组与空白对照组测试情况比较、各实验组组间比较 ,干预前、后测试结果比较 ,对干预效果进行评价。结果  3个干预实验组与对照组相比 ,SCL - 90测试结果均低于对照组 ;干预前后SCL - 90测试总分、总均分、各因子分差异有显著性意义 (P <0 0 0 1)。结论  3种干预方式对心理障碍均有不同程度的疗效 ,以中药与心理疗法结合治疗效果最佳。  相似文献   
96.
目的 探讨牙齿不同部位之间、易患龋牙与非易患龋牙之间牙釉质表面氟浓度有无差异。方法 收集上海、北京和深圳3个地区儿童的下颌乳中切牙45颗,并利用微样酸蚀法分析乳牙釉质表面氟元素的分布。结果 氟浓度从釉质表面到内部有由高到低的变化趋势,牙磨耗是牙齿丧失氟的重要元素,未发现釉质表层氟浓度与龋蚀指数(CSI)、龋补牙数(dft)有相关性(P>0.05)。结论 乳牙釉质表面氟浓度与患龋状况无明显相关性。  相似文献   
97.
刘鑫  刘岚 《中国医学伦理学》2003,16(1):44-44,47
功能性矫治器是正畸临床中常用的一种矫治器,作者从口腔正畸学理论基础出发,探讨了功能性矫治器在正畸矫治作用中存在的伦理道德问题,主要有(1)不能正确的诊断、制定周密的矫治计划。(2)操作不规范、不细致、缺乏敬业精神。(3)态度简单,粗曝,缺乏与患者良好的交流。并提出解决方法(1)刻苦学习专业知识,不断提高诊疗水平及个人修养。(2)建立高度的道德责任感,以严谨的作风,规范的操作为病人服务。(3)尊重、善待青少年,建立良好的医患关系。  相似文献   
98.
The aim of the present study was to evaluate the combined application of different bioabsorbable materials for healing of residual peri‐implant defects after placement of non‐submerged implants into fresh extraction sockets. Second and third mandibular premolars were extracted from 10 Beagle dogs, the coronal part of the distal sockets were surgically enlarged and this was followed by immediate placement of specially designed hollow‐screw non‐submerged dental implants. For each animal, the coronal peri‐implant defects were further treated with one of the 4 following procedures: 1) no treatment, control site: 2) grafting with porous hydroxyapatite (HA); 3) collagen membrane tightly secured around the implant and over the defect and 4) grafting with HA covered with a collagen membrane. After 16 weeks of healing, specimens were removed from the mandibule and prepared for a histomorphometric evaluation. The bone-to-implant contact length (BIC) was measured and compared amongst the different treatment modalities. In the defect area, the irregular bone regeneration was similar between all the treatment procedures ( P >0.10). In the sites covered with a collagen membrane alone, the total BIC (47%) was greater than in control sites (28.7%. P <0.05) or sites grafted with HA (22.2%, P <0.02). Total BIC in sites treated with the HA‐membrane combination (43%) was only significantly different from sites treated with HA ( P <0.10). It is concluded that the use of bioabsorbable materials results in a limited increase of osseointegration when used in conjunction with immediate placement of non-submerged implants, although the principle of the one stage surgical approach can be maintained.  相似文献   
99.
The purpose of this study was to compare the attitudes toward basic sciences of students in a preclinical problem-based curriculum and a conventional lecture-based curriculum at the end of their second year of medical school. The results showed that the PBL class had more positive attitudes toward basic sciences than students in the conventional class. These results may reflect a learning environment where students meet many scientist role models as teachers and where basic science is learnt in the context of clinical problems.  相似文献   
100.
Abstract The treatment-mix, treatment time, and dental status of 268 male industrial workers entitled to employer-provided dental care were studied. The data were collected from treatment records of the covered workers over the 5-year period 1989-93. Treatment time was based on clinical treatment time recorded per patient visit, and the treatment procedure codes were reclassified into a treatment-mix according to American Dental Association categories, with a modification combining endodontics and restorative treatment. The mean number of check-ups followed by prescribed treatment (treatment courses) during the 5 years was 3.7 among those who had entered the in-house dental care program prior to the monitored period (old attenders). Their treatment time was stable, 57–63 min per year, while the first-year mean treatment time (170 min) of those who had entered the program during the study period (new attenders) was significantly higher (P<0.01) than the 5-year mean of the old attenders (61 min). Over the first 2 years, the treatment-mix of the new attenders showed a rise in diagnostic and preventive procedures from one-third to about one-half of all procedures, as it was for the old attenders. The new attenders' mean number of carious teeth (2.7), registered at the initial check-up visit, paralleled the mean recently demonstrated in the similar non-covered population. It was significantly higher than the 5-year mean of the old attenders (0.5) (P<0.001), but declined to the same level after the first year of treatment. It was concluded that the studied program seemed to contribute to a stabilization of treatment-mix, and to the establishment of a shorter annual treatment time within the first 2 years of treatment.  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