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   6073篇
  免费   363篇
  国内免费   172篇
耳鼻咽喉   60篇
儿科学   55篇
妇产科学   92篇
基础医学   750篇
口腔科学   215篇
临床医学   749篇
内科学   581篇
皮肤病学   36篇
神经病学   182篇
特种医学   289篇
外科学   1142篇
综合类   1002篇
预防医学   453篇
眼科学   153篇
药学   532篇
  5篇
中国医学   165篇
肿瘤学   147篇
  2024年   29篇
  2023年   219篇
  2022年   412篇
  2021年   435篇
  2020年   361篇
  2019年   225篇
  2018年   135篇
  2017年   136篇
  2016年   136篇
  2015年   139篇
  2014年   352篇
  2013年   343篇
  2012年   331篇
  2011年   353篇
  2010年   288篇
  2009年   268篇
  2008年   258篇
  2007年   228篇
  2006年   253篇
  2005年   238篇
  2004年   196篇
  2003年   194篇
  2002年   137篇
  2001年   107篇
  2000年   104篇
  1999年   89篇
  1998年   64篇
  1997年   68篇
  1996年   56篇
  1995年   54篇
  1994年   62篇
  1993年   38篇
  1992年   32篇
  1991年   17篇
  1990年   29篇
  1989年   22篇
  1988年   19篇
  1987年   30篇
  1986年   24篇
  1985年   22篇
  1984年   16篇
  1983年   14篇
  1982年   8篇
  1981年   11篇
  1980年   12篇
  1979年   6篇
  1978年   7篇
  1977年   8篇
  1974年   5篇
  1973年   6篇
排序方式: 共有6608条查询结果,搜索用时 15 毫秒
141.
PurposeTo compare the evaluation of malignant focal liver lesions (FLLs) using a semi-automated RECIST tool with a standard and an ultra-low dose (ULD) computed tomography (CT) protocol.Materials and methodsThirty-four patients with malignant FLLs underwent two abdominal-pelvic CT examinations one using a standard protocol and one using an ULD protocol. There were 23 men and 11 women with a mean age 64.3 ± 14.4 (SD) years (range: 22–91 years). Dosimetric indicators were recorded, and effective dose was calculated for both examinations. Mean malignant FLL attenuation, image noise and contrast-to-noise-ratio (CNR) were compared. The largest malignant FLL per patient was evaluated using the semi-automated RECIST tool to determine longest axis length, longest orthogonal axis length, volume and World Health Organisation area.ResultsDosimetric values were significantly reduced by −56% with ULD compared to standard protocol. No differences in mean malignant FLL attenuation values were found between the two protocols. Image noise was significantly increased for all locations (P < 0.05) with ULD compared to standard protocol, and CNR was significantly reduced (P < 0.05). On the 34 malignant FLLs analyzed, six semi-automated shapes non-concordant with radiologist's visual impression were highlighted with the software, including one FLL (1/34; 3%) with standard CT acquisition only, three FLLs (3/34; 9%) with ULD CT acquisition only and two FLLs (2/34; 6%) with both CT acquisitions. After manual editing, the concordance of the values of the studied criteria between both acquisitions was good and no significant difference was reported.ConclusionSemi-automated RECIST tool demonstrates good performances using ULD CT protocol. It could be used in routine clinical practice with a ULD protocol for follow-up studies in patients with known malignant FLL.  相似文献   
142.
Following the transection and repair of major nerve trunks in the forearm, the functional outcome is influenced by mechanisms in the peripheral, as well as in the central nervous system. In the present thesis the interest is focused on assessment of the outcome after nerve repair, central nervous factors influencing the outcome, and sense substitution to compensate for sensory loss. A new model instrument for routine documentation of the outcome after repair of a peripheral nerve is identified. The model includes assessments reflecting sensory, motor and pain/discomfort domains. Investigations of frequently used assessment instruments led to the construction and evaluation of a new test instrument for assessment of discriminative sensibility (tactile gnosis) to fit in the model. The summarised outcome, calculated from the model instrument and with a numerical scoring system, conforms well with the patient's opinion on the influence on activities of daily living resulting from the nerve injury, and demonstrates good reliability and validity. A reference interval for the outcome is presented, with the estimated 95% predicted values for the outcome up to five years after the nerve repair. Brain plasticity is a factor sensibility - tactile gnosis - in the adaptive process after a nerve injury, when the mind has to interpret new signal patterns, when objects are touched. For better understanding of the sensory outcome after nerve repair, central nervous factors were examined. Specific cognitive capacities, such as verbal learning and visuo-spatial logic capacity could be identified as being of importance for recovery of tactile gnosis. For patients with temporary or permanent sensory loss, a new principle for artificial sensibility based on sense substitution is presented. The hearing sense substitutes the sense of touch. The resemblance in perceptual experience between sound and touch is bridged by the stereophonic friction sound generated by touching objects, which is then amplified and transmitted to earphones. The delicate capacity of the sense of hearing to discriminate between the complex pattern of frequencies makes it reasonable to assume that hearing is able to take over functions normally devoted to touch. This is demonstrated in the thesis.  相似文献   
143.
The calibration status of bone vibrators in selected audiology clinics was examined with the use of a Beltone mechanical coupler. Outputs of bone vibrators were measured and compared to Hearing Aid Industries Conference (HAIC) Interim Standard values. The results suggest that the status of calibration of bone vibrators, in the 16 clinics sampled, did not conform to HAIC Interim Standards for 76% of the measurements  相似文献   
144.
《Drug discovery today》2021,26(11):2489-2495
Spiralling research costs combined with urgent pressures from the Coronavirus 2019 (COVID-19) pandemic and the consequences of climate disruption are forcing changes in drug discovery. Increasing the predictive power of in vitro human assays and using them earlier in discovery would refocus resources on more successful research strategies and reduce animal studies. Increasing laboratory automation enables effective social distancing for researchers, while allowing integrated data capture from remote laboratory networks. Such disruptive changes would not only enable more cost-effective drug discovery, but could also reduce the overall carbon footprint of discovering new drugs.  相似文献   
145.
Neglect patients' performance during cancellation tasks is characterized by left sided omissions and, in many cases, by the production of inappropriate material of various kinds in the ipsilesional space, e.g. additional marks over already cancelled targets, marks drawn away from targets, scribbles, irrelevant drawings. It is unclear whether these behaviours, which have collectively been called perseverative, are functionally and anatomically connected and whether they correlate with the severity of neglect. Here we report a retrospective study on 33 right brain damaged patients with neglect after right hemisphere lesions in whom we measured the intensity of perseveration of the three following kinds: (1) ‘additional marks' (AM) perseveration where patients cancelled a target with two or more well separated marks; (2) ‘scribble’ perseveration, where patients, instead of cancelling the target with a single pen stroke as required by the task, performed multiple pen strokes without breaking the pen-to-paper contact, with the final product being a scribble; (3) ‘flying marks’ (FM) perseveration where patients produced cancellation marks well away from the targets. We found that AM and FM perseveration correlated with neglect severity, while ‘scribble’ perseveration did not. The lesion-symptom mapping showed three separate anatomical areas in the right hemisphere: ‘scribble’ perseveration was associated with lesions of the orbitofrontal cortex and caudate nucleus; AM perseveration was associated with damage to the rolandic operculum, superior temporal gyrus and inferior frontal gyrus; FM perseveration was associated with damage to the dorsal premotor cortex and the temporal pole. Neglect severity followed damage to a region which grossly corresponds to the sum of the regions associated with AM and FM perseveration respectively. This complex behavioural and anatomical pattern is interpreted in terms of a three-factor model, in which AM perseveration is caused by a deficit of disengagement of attention from the right side (also causing omissions), FM perseveration is caused by directional hypokinesia (also causing left-side omissions), and ‘scribble’ perseveration is the consequence of a failure to inhibit an initiated motor act, which is completely separate (both anatomically and functionally) from the disorder inducing omissions.  相似文献   
146.
147.
伍琼珍 《现代预防医学》2012,39(8):2104+2107
目的总结人工关节置换术病人的护理经验。方法对21例关节置换术病人从心理护理、术前准备、术后护理和康复指导方面帮助患者恢复肢体功能,提高生活质量。结果 21例患者中,除1例因有脑梗塞后遗症,一侧肢体活动不灵,不能早期下床活动外,其余20例患者出院前均可下床活动,肢体功能恢复好。结论人工关节置换术是帮助患者尽早恢复肢体功能和恢复生产生活的好方法。  相似文献   
148.
罗海娟 《医学理论与实践》2012,25(13):1557-1558,1582
目的:探讨联合应用消化道干预措施对降低新生儿黄疸的效果。方法:将192例正常足月新生儿随机分为直接消化道干预组、间接消化道干预组、综合组。间接消化道干预组应用游泳并抚触措施、直接消化道干预组应用早期通便措施、综合组联合应用游泳并抚触及早期通便两种措施,比较3组胎粪初排时间、胎粪转黄时间、每日排便次数、生后1~6d黄疸指数及病理性黄疸发生率。结果:综合组胎粪初排时间及胎粪转黄时间较直接消化道干预组和间接消化道干预组提前(P<0.01),每日排便次数较其他两组增多(P<0.01),生后3~6d黄疸指数及病理性黄疸发生率比两组降低(P<0.01)。结论:联合应用消化道干预措施能有效降低新生儿黄疸,减少病理性黄疸的发生率。  相似文献   
149.
150.
It seems inevitable that diagnostic and recommender artificial intelligence models will ultimately reach a point when they outperform human clinicians. Just as antibiotics displaced a host of medicinals for treating infections, the superior performance of such models will force their adoption. This article contemplates certain ethical and legal implications bearing on that adoption, especially because they involve a clinician’s exposure to allegations of malpractice. The article discusses four relevant considerations: (1) the imperative of using explainable artificial intelligence models in clinical care, (2) specific strategies for diminishing liability when a clinician agrees or disagrees with a model’s findings or recommendations but the patient nevertheless experiences a poor outcome, (3) relieving liability through legislation or regulation, and (4) comprehending such models as “persons” and therefore as potential defendants in legal proceedings. We conclude with observations on clinician–vendor relationships and argue that, although advanced artificial intelligence models have not yet arrived, clinicians must begin considering their implications now.  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