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   3182672篇
  免费   211376篇
  国内免费   4790篇
耳鼻咽喉   45106篇
儿科学   103938篇
妇产科学   88064篇
基础医学   463509篇
口腔科学   88365篇
临床医学   282591篇
内科学   608599篇
皮肤病学   69173篇
神经病学   250161篇
特种医学   120017篇
外国民族医学   818篇
外科学   479106篇
综合类   66874篇
现状与发展   12篇
一般理论   1076篇
预防医学   245463篇
眼科学   74575篇
药学   237360篇
  71篇
中国医学   6177篇
肿瘤学   167783篇
  2019年   25195篇
  2018年   34213篇
  2017年   25735篇
  2016年   28918篇
  2015年   32684篇
  2014年   45857篇
  2013年   69258篇
  2012年   95427篇
  2011年   101715篇
  2010年   60456篇
  2009年   57001篇
  2008年   96250篇
  2007年   102847篇
  2006年   104012篇
  2005年   101189篇
  2004年   97071篇
  2003年   93625篇
  2002年   91105篇
  2001年   140657篇
  2000年   144273篇
  1999年   121678篇
  1998年   35864篇
  1997年   31568篇
  1996年   31934篇
  1995年   30054篇
  1994年   27880篇
  1993年   26210篇
  1992年   95928篇
  1991年   93832篇
  1990年   91977篇
  1989年   88996篇
  1988年   82236篇
  1987年   80729篇
  1986年   76356篇
  1985年   73189篇
  1984年   54663篇
  1983年   46808篇
  1982年   28143篇
  1979年   51150篇
  1978年   36364篇
  1977年   30737篇
  1976年   29281篇
  1975年   31898篇
  1974年   37899篇
  1973年   36333篇
  1972年   34318篇
  1971年   32357篇
  1970年   29953篇
  1969年   28644篇
  1968年   26634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.
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   
5.
6.
7.
8.
9.

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   
10.

Aims

To examine the influence of pre-existing psychiatric disorder on the choice of treatment in patients with gynaecological cancer.

Materials and methods

The analyses were based on all patients who underwent surgical treatment for endometrial, ovarian or cervical cancer who were registered in the Danish Gynecological Cancer Database in the years 2007–2014 (3059 patients with ovarian cancer, 5100 patients with endometrial cancer and 1150 with cervical cancer). Logistic regression model and Cox regression model, adjusted for relevant confounders, were used to estimate the effect of pre-existing psychiatric disorder on the course of cancer treatment. Our outcomes were (i) presurgical oncological treatment, (ii) macroradical surgery for patients with ovarian cancer, (iii) radiation/chemotherapy within 30 days and 100 days after surgery and (iv) time from surgery to first oncological treatment.

Results

In the group of patients with ovarian cancer, more patients with a psychiatric disorder received macroradical surgery versus patients without a psychiatric disorder, corresponding to an adjusted odds ratio of 1.24 (95% confidence interval 0.62–2.41) and the chance for having oncological treatment within 100 days was odds ratio = 1.26 (95% confidence interval 0.77–2.10). As for patients with endometrial cancer, all outcome estimates were close to unity. The adjusted odds ratio for oncological treatment within 30 days after surgery in patients with cervical cancer with a history of psychiatric disorder was 0.20 (95% confidence interval 0.03–1.54).

Conclusions

We did not find any significant differences in the treatment of ovarian and endometrial cancer in patients with pre-existing psychiatric diagnoses. When it comes to oncological treatment, we suggest that increased attention should be paid to patients with cervical cancer having a pre-existing psychiatric diagnosis.  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