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   2657682篇
  免费   191812篇
  国内免费   3751篇
耳鼻咽喉   36503篇
儿科学   86430篇
妇产科学   71468篇
基础医学   395559篇
口腔科学   73469篇
临床医学   237766篇
内科学   511844篇
皮肤病学   59209篇
神经病学   208456篇
特种医学   99072篇
外国民族医学   545篇
外科学   399874篇
综合类   53179篇
现状与发展   12篇
一般理论   936篇
预防医学   207701篇
眼科学   62431篇
药学   199000篇
  11篇
中国医学   5141篇
肿瘤学   144639篇
  2019年   21315篇
  2018年   29597篇
  2017年   22219篇
  2016年   24884篇
  2015年   28035篇
  2014年   39521篇
  2013年   59473篇
  2012年   81830篇
  2011年   87325篇
  2010年   51718篇
  2009年   48982篇
  2008年   82408篇
  2007年   87727篇
  2006年   88713篇
  2005年   85791篇
  2004年   82333篇
  2003年   79226篇
  2002年   76748篇
  2001年   121892篇
  2000年   125211篇
  1999年   105043篇
  1998年   30260篇
  1997年   26487篇
  1996年   27013篇
  1995年   25424篇
  1994年   23469篇
  1993年   22137篇
  1992年   81264篇
  1991年   79477篇
  1990年   77889篇
  1989年   75055篇
  1988年   68977篇
  1987年   67779篇
  1986年   63405篇
  1985年   60878篇
  1984年   45165篇
  1983年   38470篇
  1982年   22727篇
  1979年   41982篇
  1978年   30114篇
  1977年   25036篇
  1976年   23949篇
  1975年   26019篇
  1974年   31213篇
  1973年   29664篇
  1972年   27866篇
  1971年   26606篇
  1970年   24536篇
  1969年   23339篇
  1968年   21547篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
3.
4.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
5.
Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments.  相似文献   
6.
7.
8.

Background

Obesity is a risk factor for acetabular component malposition when total hip arthroplasty is performed with manual techniques. The utility of imageless navigation in obese patients remains unknown. This study compared the accuracy and precision of imageless navigation for component orientation between obese and nonobese patients.

Methods

A total of 459 total hip arthroplasties performed for osteoarthritis using imageless navigation were reviewed from a single surgeon’s institutional review board–approved database. Einzel-Bild-Roentgen Analyse determined component orientation on 6-week postoperative anteroposterior radiographs. Mean orientation error (accuracy) and precision were compared between obese (body mass index ≥ 30 kg/m2) and nonobese patients. Regression analysis evaluated the influence of obesity on component position.

Results

The difference in mean inclination and anteversion between obese and nonobese groups was 1.1° (43.0° ± 3.5°; range, 35.8°-57.8° vs 41.9° ± 4.4°; range, 33.0°-57.1° and 24.9° ± 6.3°; range, 14.2°-44.3° vs 23.8° ± 6.6°; range, 7.0°-38.6°, respectively). Inclination precision was better for nonobese patients. No difference in inclination accuracy or anteversion accuracy or precision was detected between groups. And 83% of components were placed within the target range. There was no relationship between obesity (dichotomized) and component placement outside the target ranges for inclination, anteversion, or both. As a continuous variable, increased body mass index correlated with higher odds of inclination outside the target zone (odds ratio, 1.06; P = .001).

Conclusion

Using imageless navigation, inclination orientation was less precise for obese patients, but the observed difference is likely not clinically relevant. Accurate superficial registration of landmarks in obese patients is achievable, and the use of imageless navigation similarly improves acetabular component positioning in obese and nonobese patients.

Level of Evidence

Therapeutic Level IV.  相似文献   
9.
Abstract

This study is a single-center, retrospective analysis of postmenopausal women presenting with dyspareunia and vulvar pain, aiming to evaluate relative effectiveness of vestibular CO2 laser therapy as a treatment. Three monthly sessions of laser were performed to each patient and thereafter a three-months follow-up was stablished. A total number of 72 patients undergoing vestibular laser treatment were recruited from patient files in the period between 2016 and 2018. Among these, 39 women also received a concomitant treatment with ospemifene (60?mg/day) during the study period. There was a statistically significant reduction of all the symptoms in both groups up to the three month follow-up. Regarding dryness and dyspareunia, the relief tent to be more prominent in the ospemifene?+?laser group at all follow-ups and remained statistically significant at three-month follow-up. Specifically, vestibular dryness was significantly lower in the ospemifene?+?laser group compared with the laser treatment group (?87% vs???34%, respectively), and the vestibular health score started declining faster in the ospemifene?+?laser group. Although, additional research is needed to understand the mechanism of action, our data shows that a combination regimen of laser and ospemifene may improve clinical effectiveness for long-term treatment of symptoms associated with the under-recognized genitourinary syndrome of menopause.  相似文献   
10.
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