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   13907篇
  免费   1169篇
  国内免费   473篇
耳鼻咽喉   36篇
儿科学   164篇
妇产科学   173篇
基础医学   832篇
口腔科学   328篇
临床医学   1599篇
内科学   918篇
皮肤病学   209篇
神经病学   529篇
特种医学   241篇
外科学   832篇
综合类   2425篇
一般理论   5篇
预防医学   3485篇
眼科学   333篇
药学   1711篇
  35篇
中国医学   1327篇
肿瘤学   367篇
  2024年   30篇
  2023年   200篇
  2022年   277篇
  2021年   485篇
  2020年   485篇
  2019年   477篇
  2018年   424篇
  2017年   506篇
  2016年   556篇
  2015年   507篇
  2014年   797篇
  2013年   1120篇
  2012年   823篇
  2011年   866篇
  2010年   629篇
  2009年   592篇
  2008年   695篇
  2007年   740篇
  2006年   637篇
  2005年   500篇
  2004年   457篇
  2003年   403篇
  2002年   359篇
  2001年   312篇
  2000年   257篇
  1999年   246篇
  1998年   199篇
  1997年   176篇
  1996年   142篇
  1995年   145篇
  1994年   148篇
  1993年   102篇
  1992年   120篇
  1991年   128篇
  1990年   105篇
  1989年   108篇
  1988年   85篇
  1987年   79篇
  1986年   105篇
  1985年   62篇
  1984年   71篇
  1983年   66篇
  1982年   71篇
  1981年   56篇
  1980年   52篇
  1979年   51篇
  1978年   26篇
  1977年   16篇
  1976年   22篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Prof. Dr.  O. P. Steeno 《Andrologia》1989,21(2):103-112
Summary: For the quantitative determination of the testicular size or volume, two groups of apparatus are available: on the one hand, model testes, which are extremely valuable in longitudinal and cross-sectional studies during the period of pubescence, and on the other hand, measuring devices, with which the testicular dimensions can be specified. The latter instruments are helpful chiefly during the adolescent years and the diagnosis of problems surrounding fertility. The testicular volume can be calculated subsequently from the specific testicular measurements. The formula, for computing the volume of an ellipsoid, seems to be the most suitable for this purpose. Appliances also have been developed, which allow the largest (longitudinal) dimension (in mm) and the testicular volume (in cm3) to be read off simultaneously. A tonometer can be useful to quantitatively estimate the testicular consistency, which is a parameter of the testicular integrity at the level of tubular function (spermatozoa production).  相似文献   
52.
本文简单介绍冷冻断裂复型电镜技术在国内、外的概况,並阐明了该项新技术的独特作用和具体的操作步骤;在制作生物样品时所需的仪器设备和试剂的配制等内容。  相似文献   
53.
Currently few subjective measures of Quality of Life (QoL) are available for use in developing countries, which limits their theoretical, methodological, and practical contribution (for example, exploring the relationship between economic development and QoL, and ensuring effective and equitable service provision). One reason for this is the difficulty of ensuring that translated measures preserve conceptual, item, semantic, operational, measurement; and functional equivalence (Herdman, M., Fox-Rushby, J., & Badia, X. (1998). Quality of Life Research, 7, 331), which is illustrated by an account of the translation, pre-piloting, and administration of a new individualised QoL measure, the Global Person Generated Index or 'GPGI'. The GPGI is based on the widely used Patient Generated Index (Ruta, Camfield, & Martin, (2004) Quality of Life Research, 13, 1545.) and offers many of the advantages of the participatory approaches commonly used in developing countries, with added methodological rigour, and quantitative outcomes. It was successfully validated in Bangladesh, Thailand, and Ethiopia, using quantitative and qualitative methods--open-ended, semi-structured interviews (SSIs), conducted immediately post-administration. Both the measure and method of 'qualitative validation' described later in the paper offer an exciting alternative for future researchers and practitioners in this field. The quantitative results suggest the GPGI shows cultural sensitivity, and is able to capture both the areas that are important to respondents, and aspects of life one would expect to impact on QoL in developing countries. There were strong correlation between scores from the GPGI and SSIs for the area of health, and moderate correlations for 'material wellbeing' (MWB)('Material wellbeing' refers to respondents' perceptions of their achievement in the areas of farming, debt reduction, assets, crops, livestock, job, land, property, and agriculture) and children. Weak to moderate correlations were observed between the Satisfaction with Life Scale and the GPGI; however, the highest coefficient was between the GPGI and the most conceptually similar item. Statistically significant differences were seen in GPGI scores between rich and poor, urban and rural respondents, and different countries. Health and material wellbeing scores, derived from the SSIs, also showed a linear relationship with GPGI scores, with a suggestion of curvilinearity at the higher levels, as predicted by a general QoL causal model. In conclusion, the GPGI has great potential for use in this area, especially when supported by extensive interviewer training, and supplemented with a cognitive appraisal schedule.  相似文献   
54.
This article, based on a report prepared for the International Council of Ophthalmology (ICO) and the International Society for Low Vision Research and Rehabilitation (ISLRR), explores the assessment of various aspects of visual functioning as needed to document the outcomes of vision rehabilitation. Documenting patient abilities and functional vision (how the person functions) is distinct from the measurement of visual functions (how the eye functions) and also from the assessment of quality of life. All three areas are important, but their assessment should not be mixed. Observation of task performance offers the most objective measure of functional vision, but it is time‐consuming and not feasible for many tasks. Where possible, timing and error rates provide an easy score. Patient response questionnaires provide an alternative. They may save time and can cover a wider area, but the responses are subjective and proper scoring presents problems. Simple Likert scoring still predominates but Rasch analysis, needed to provide better result scales, is gaining ground. Selection of questions is another problem. If the range of difficulties does not match the range of patient abilities, and if the difficulties are not distributed evenly, the results are not optimal. This may be an argument to use different outcome questions for different conditions. Generic questionnaires are appropriate for the assessment of generic quality of life, but not for specific rehabilitation outcomes. Different questionnaires are also needed for screening, intake and outcomes. Intake questions must be relevant to actual needs to allow prioritization of rehabilitation goals; the activity inventory presents a prototype. Outcome questions should be targeted at predefined rehabilitation goals. The Appendix cites some promising examples. The Low Vision Intervention Trial (LOVIT) is an example of a properly designed randomized control study, and has demonstrated the remarkable effectiveness of vision rehabilitation. It is hoped that further similar studies will follow.  相似文献   
55.
C型骨盆骨折合并髋关节中心性脱位的手术治疗   总被引:1,自引:1,他引:0       下载免费PDF全文
万仑  吕波  刘仲前 《中国骨伤》2006,19(6):348-350
目的:研究C型骨盆骨折合并髋关节中心性脱位的临床疗效。方法:13例患者中男8例,女5例;年龄23~65岁,平均36.5岁。骨盆骨折分型:C1型8例,C2型3例,C3型2例。髋臼“T”形骨折2例,粉碎性骨折9例,双柱骨折2例。均采用手术治疗,术前术后均采用股骨髁上牵引,术中采用髂腹股沟入路,必要时附加患髋后外侧切口,术中采用重建钢板固定。结果:本组随访时间6~28个月,平均13.4个月。髋臼骨折复位后残存移位:0~1mm9例,2~3mm2例,4~5mm2例,无>5mm者。髂骨骨折复位后各向残存移位:0~1mm9例,2~5mm3例,>5mm1例。3例原发性坐骨神经损伤的患者,术后3个月内其感觉、运动功能全部获得恢复。1例继发性坐骨神经损伤,术后6个月恢复。异位骨化2例,股骨头坏死、髋臼及股骨头软骨坏死、髋关节创伤性关节炎5例,患者关节疼痛、活动受限,影响功能。疗效综合评定:优8例,良1例,可2例,差2例。结论:C型骨盆骨折合并髋关节中心性脱位通过手术治疗,能够最大程度恢复其解剖结构,术后关节功能恢复较好。  相似文献   
56.
目的 :改进斑点免疫金渗滤法的渗滤装置 ,降低成本 ,使之更适用于现场操作。方法 :用自制的圆形渗滤片替代塑料渗滤盒 ,并比较二者的效果。结果 :自制的渗滤片体积更小 ,成本更低 ,为一次性使用材料 ;检测抗体的效果与塑料渗滤盒法一致。结论 :自制的渗滤片优于常用的塑料渗滤盒  相似文献   
57.
对两种性能较好的快离子导体Na_3Zr_2Si_2P_3O_(12)(Nasicon)和Li_(1.8)Ti_(1.2)·Cr_(0.8)P_3O_(12)用喷雾干燥法和冰冻干燥法制备粉料和陶瓷烧结,并对样品进行了X射线衍射分析,形貌和显微结构观察以及阻抗谱测量等。实验结果表明:两种方法制备的粉料具有颗粒细,均匀性好,合成温度低等优点。在300℃时,两种样品的电阻半分别为10.05 Ω.cm和94.8 Ω.cm。激活能分别为0.25 eV和0.27ev。  相似文献   
58.
A structured clinical examination has been an integral component of the final-year examinations conducted by the Departments of Medicine and Surgery at the University of Adelaide for the last 8 years. It has been used as an alternative to the traditional clinical examination. This paper describes the results of ongoing student and examiner surveys carried out to determine their views and satisfaction with this new approach. It also briefly discusses the feasibility of introducing such an examination into a conventional medical school environment. The surveys showed a remarkable level of acceptance and support by both students and examiners. This positive reaction has been maintained over the 8-year period. The main reasons seem to be its perceived relevance and fairness. Students also appear to be directing their learning in a direction thought desirable by teachers. No significant problems have been encountered with the practical implementation of the method.  相似文献   
59.
报告120例羊膜腔穿刺羊水细胞培养结果:在成功的99例中,发现二例染色体异常,核型为47,xy,+18和46,xx/47,xx,+F,在21例失败中出现一例眼球畸形。培养成功率为82.5%;染色体异常检出率为2.02%。无一例因羊膜腔穿刺而导致流产,但出现一例轻度羊水栓塞合并症。并对羊水细胞培养在产前宫内诊断中应用价值及术后并发症进行了讨论。  相似文献   
60.
This study investigated a discrete-trial, titration duration discrimination procedure in behavioral pharmacology. Pentobarbital and d-amphetamine, measured with this procedure, selectively affected discrimination more than response tendencies. Pentobarbital also tended to affect selectively discrimination of longer durations, whereas d-amphetamine did not. Further experiments showed that (1) other algorithms for modulating stimulus duration are useful in behavioral pharmacology and toxicology, (2) threshold estimates are similar with the method of constant stimuli and the method of titration, and (3) this titration procedure permits the separate examination of drug effects upon discrimination and upon response tendencies; the fixed-interval procedure does not. Baseline variability was an important correlate of drug effects in that the endpoints with more variable baselines were also more sensitive to drugs.  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