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   262篇
  免费   19篇
耳鼻咽喉   10篇
儿科学   42篇
妇产科学   12篇
基础医学   43篇
口腔科学   3篇
临床医学   44篇
内科学   11篇
皮肤病学   4篇
神经病学   40篇
特种医学   2篇
外科学   18篇
综合类   2篇
预防医学   37篇
眼科学   4篇
药学   4篇
肿瘤学   5篇
  2020年   2篇
  2018年   4篇
  2016年   2篇
  2014年   3篇
  2013年   12篇
  2012年   2篇
  2011年   3篇
  2010年   4篇
  2009年   5篇
  2008年   7篇
  2007年   13篇
  2006年   9篇
  2005年   10篇
  2004年   7篇
  2003年   7篇
  2002年   10篇
  2001年   9篇
  2000年   11篇
  1999年   14篇
  1998年   2篇
  1996年   5篇
  1995年   4篇
  1994年   11篇
  1993年   3篇
  1992年   13篇
  1990年   13篇
  1989年   8篇
  1988年   9篇
  1987年   11篇
  1986年   6篇
  1985年   6篇
  1984年   4篇
  1983年   4篇
  1982年   5篇
  1981年   3篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1974年   2篇
  1972年   4篇
  1971年   6篇
  1969年   2篇
  1967年   1篇
  1966年   1篇
  1964年   1篇
  1956年   1篇
  1944年   2篇
  1943年   1篇
  1937年   1篇
  1935年   2篇
排序方式: 共有281条查询结果,搜索用时 15 毫秒
1.
Eye movements were studied in 13 patients with Friedreich's ataxia and correlated with MRI findings to investigate whether oculomotor abnormalities can be traced to cerebellar disturbances in this disease. One of the most prominent eye signs was fixation instability (square-wave jerks, SWJ.). Besides SWJ the patients showed various combinations of cerebellar, vestibular and brain-stem oculomotor signs. Our patients did not comprise a homogeneous group with regard to their oculomotor findings. There was no correlation between the severity of any of the so-called cerebellar oculomotor disturbances and the number of SWJ. We tried to correlate the extent of oculomotor disturbances with floccular atrophy and atrophy of the dorsal vermis on MRI in seven of the patients. None of the oculomotor features (including SWJ) correlated with flocculus or dorsal vermis size. Furthermore, floccular and vermal measurements on MRI were normal. Accordingly, we think it unlikely that the oculomotor disturbances, including SWJ, are attributable to cerebellar pathology per se.  相似文献   
2.
Heat-inactivated human serum is added to the culture medium used for in vitro fertilization and other forms of assisted conception. Because one batch of pooled serum contained hepatitis B virus, an epidemic occurred among women participating in the treatment program. Seventy-nine women had serologic proof of hepatitis B infection. This incident gave the opportunity to study the effect of hepatitis B virus on pregnancy outcome and the newborn. The situation is unique because the preimplantation embryo was exposed to hepatitis B virus or the pregnancy was complicated by a (sub)clinical infection. Twenty-four women were or became pregnant while having an acute hepatitis B infection. Five pregnancies ended in abortion. The remaining 19 pregnancies ended in the birth of 24 children. No evidence for any harmful effect of exposure to hepatitis B virus in the embryonic or fetal period on the newborn could be found.  相似文献   
3.
The association of prenatal exposure to diethylstilbestrol (DES) and abnormalities in structures of müllerian (paramesonephric) origin has been well documented. In a murine model, exposure to DES in utero results in persistent mesonephric remnants in adult female mice. Six women exposed prenatally to DES had paraovarian cysts excised during routine gynecologic surgery; and in 4, histologic abnormalities were observed, including thickened fibromuscular walls with tall columnar epithelium in a papillary or pseudoglandular configuration. Four of 25 nonexposed and 8 of 9 DES-exposed infertile women undergoing surgery for infertility had paraovarian cysts, and the difference was statistically significant (P less than 0.02). These findings raise the possibility that structures derived from the mesonephric ducts or tubules may also be affected in women exposed in utero to DES.  相似文献   
4.
Communication in the classroom is often a problem for both students and teachers. Previous research has shown that non-verbal teaching behavior can have a profound effect on students when mixed with verbalization and may serve as a major source of confusion. Misinterpretation is common and in the area of health education may foster the development of negative health attitudes. Health education is a shared experience of students and their teacher, one which should be comfortable and supportive. It is the educators responsibility to develop teaching behaviors that are encouraging, inspiring, and comfortable. This can be accomplished by using a variety of techniques requiring a minimum of time, equipment and energy. The purpose of this article is to demonstrate the need for cognizance of personal teaching behaviors and to suggest methods to evaluate these behaviors.  相似文献   
5.
6.
Vertigo and dizziness are common complaints encountered in clinical practice. The patient’s history and a thorough otoneurological evaluation are essential for identifying the specific pathology behind the patient’s complaints. If the patient reports an illusion of movement (vertigo), this most likely indicates an imbalance within the vestibular system. A sensation of rotatory movement together with a spontaneous nystagmus suggests a lesion involving the semicircular canals, while an illusion of linear movement indicates a disturbance of the otoliths. Nystagmus of central origin or caused by a peripheral vestibular lesion can usually be distinguished by other features in the history or on clinical examination. While peripheral vestibular lesions usually lead to a mixed horizontal-torsional or vertical-torsional nystagmus, a pure vertical or pure torsional nystagmus is always caused by a central lesion. With simple bedside tests such as head-shaking nystagmus and rapid head impulses deficits in labyrinthine function can clearly be detected. For a more thorough investigation of vestibular function at the level of individual semicircular canals and the otoliths, modern techniques are now available such as three-dimensional eye movement vector analysis for the evaluation of individual semicircular canal function, measurement of the subjective visual vertical for utricular, and click-evoked myogenic potentials for saccular testing. Received: 3 October 1999/Accepted: 7 December 1999  相似文献   
7.
Disaster literature suggests that children's and adolescents’ post-disaster reactions vary according to their developmental levels. Preschool children show less psychological problems as compared to older children and adolescents, but they have a higher incidence of trauma-specific fears and behavioral problems (e.g., dependency, clinging). School-age children's disaster responses include sleep and eating disturbances, behavioral problems, and poor school performance. Adolescents tend to exhibit symptoms such as posttraumatic stress disorder, depression, anxiety, belligerence, and pessimistic views about the future (Korol, Green, &; Gleser, ).  相似文献   
8.
A noninvasive procedure has been developed to assess effectiveness of activity-sensing rate response ventricular (VVIR) pacing systems in patients with implanted conventional fixed-rate ventricular (VVI) pacemakers capable of triggered mode operation (VVT). A VVIR pacemaker (activity threshold medium or low, rate response 6 to 10, upper rate 125 or 150 beats/min) was strapped to the chest wall (prepectoral area) of patients with previously implanted fixed-rate VVI pacemakers. In 17 of the 18 patients included in the study, the implanted pacemaker was capable of triggered mode operation (VVT). Triggering of the conventional pacemaker was achieved by reprogramming it to the VVT mode (high sensitivity, short refractory) and connecting the output of the "strapped-on" VVIR pacemaker (5 volts, 1.5-ms pulse width) to 2 standard cutaneous electrodes positioned so as to be in proximity to the implanted intracardiac electrode system. Patients underwent symptom-limited treadmill exercise tests during both VVI and VVIR pacing. Triggering conventional VVI pulse generators by a "strapped-on" VVIR pacing system proved feasible in 16 of 17 cases and improved overall heart rate response (fixed rate 86 +/- 22 vs VVIR 118 +/- 7 beats/min) and exercise duration (fixed rate 6.6 +/- 4.9 vs VVIR 10.1 +/- 4.8 minutes) (mean values for all patients studied during exercise testing). Triggering of a previously implanted permanent pacemaker by a strapped-on activity-triggered device may be useful to assess rate response pacing before implantation of a VVIR device in patients in whom elective pulse generator replacement is planned.  相似文献   
9.
We aimed to determine the effects of enteral supplementation of a prebiotic mixture of neutral and acidic oligosaccharides (scGOS/lcFOS/pAOS) on the faecal microbiota and microenvironment in preterm infants. Furthermore, we determined the influence of perinatal factors on the development of the faecal microbiota. In a randomised controlled trial, preterm infants with gestational age <32 weeks and/or birth weight <1,500 g received enteral supplementation of scGOS/lcFOS/pAOS or placebo (maltodextrin) between days 3 and 30 of life. Faecal microbiota, as measured with fluorescent in situ hybridisation (FISH), and microenvironment [short-chain fatty acids (SCFAs), pH, sIgA] were measured at four time points: before the start of the study and at days 7, 14 and 30 of life. In total, 113 preterm infants were included. Enteral supplementation of the prebiotic mixture increased the total bacteria count at day 14 (Exp 3.92; 95 % confidence interval [CI] 1.18–13.04, p?=?0.03), but not at day 30 (Exp 1.73; 95 % CI 0.60–5.03, p?=?0.31). There was a trend toward increased bifidobacteria counts. There was a delayed intestinal colonisation of all bacteria. Enteral supplementation of the prebiotic mixture decreased the faecal pH (Exp 0.71; 95 % CI 0.54–0.93, p?=?0.01) and there was a trend toward increased acetic acid compared to the placebo group (Exp 1.09; 95 % CI 0.99–1.20, p?=?0.10). There was no effect on sIgA (Exp 1.94; 95 % CI 0.28–13.27, p?=?0.50). Antibiotics decreased the total bacteria count (Exp 0.13; 95 % CI 0.08–0.22, p?<?0.001). Enteral supplementation of a prebiotic mixture of neutral and acidic oligosaccharides increases the postnatal intestinal colonisation. However, the extensive use of broad-spectrum antibiotics in preterm infants decreased the growth of all intestinal microbiota, thereby, delaying the normal microbiota development.  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