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   2951篇
  免费   260篇
  国内免费   34篇
耳鼻咽喉   25篇
儿科学   64篇
妇产科学   36篇
基础医学   437篇
口腔科学   41篇
临床医学   396篇
内科学   207篇
皮肤病学   37篇
神经病学   272篇
特种医学   62篇
外科学   149篇
综合类   309篇
一般理论   3篇
预防医学   610篇
眼科学   29篇
药学   410篇
中国医学   55篇
肿瘤学   103篇
  2024年   8篇
  2023年   64篇
  2022年   77篇
  2021年   123篇
  2020年   129篇
  2019年   97篇
  2018年   129篇
  2017年   115篇
  2016年   111篇
  2015年   101篇
  2014年   222篇
  2013年   251篇
  2012年   179篇
  2011年   207篇
  2010年   169篇
  2009年   164篇
  2008年   167篇
  2007年   142篇
  2006年   123篇
  2005年   76篇
  2004年   76篇
  2003年   66篇
  2002年   55篇
  2001年   39篇
  2000年   33篇
  1999年   37篇
  1998年   33篇
  1997年   15篇
  1996年   18篇
  1995年   16篇
  1994年   21篇
  1993年   12篇
  1992年   17篇
  1991年   14篇
  1990年   6篇
  1989年   12篇
  1988年   6篇
  1987年   12篇
  1986年   5篇
  1985年   13篇
  1984年   13篇
  1982年   6篇
  1981年   7篇
  1980年   5篇
  1979年   12篇
  1978年   5篇
  1976年   6篇
  1975年   6篇
  1973年   5篇
  1972年   4篇
排序方式: 共有3245条查询结果,搜索用时 31 毫秒
41.
To test the hypothesis that the etiology of individual differences in reading performance differs in males and females, reading performance data from twin pairs tested in the Colorado Learning Disabilities Research Center were fitted to structural equation models of sex limitation. The sample included 513 pairs of twins in which at least one member of each pair has a positive school history of reading problems [228 monozygotic (MZ), 176 same-sex dizygotic (DZ), and 109 opposite-sex DZ pairs] and 302 matched control pairs [148 MZ, 98 same-sex DZ, and 56 opposite-sex DZ pairs]. Estimates of the genetic correlation between performance in males and females were obtained by analysis of data from both same-sex and opposite-sex twin pairs (Neale and Cardon, 1992). The full model fit the data well 2=17,74, df=16,p=0.340), and the resulting genetic parameter estimates were highly similar in males and females in both the proband and the control samples. The correlations between genetic influences in males and females do not differ among groups (change in 2=0.95, df=1,p0.25), and the resulting pooled estimate is about .5. Thus, results of this analysis suggest that the etiology of individual differences in reading performance may differ to some extent in males and females.  相似文献   
42.
Doctor-patient interaction has gained increasing attention among sociologists and linguists during the last few decades. The problem with the studies performed so far, however, has been a lack of a theoretical framework which could bring together the various phenomena observed within medical consultations. Mikhail Bakhtin's philosophy of language offers us tools for studying medical practice as socio-cultural semiotic phenomenon. Applying Bakhtin's ideas of polyphonic, context-dependent and open-ended nature of human communication opens the possibilities to develop prevailing theoretical and empirical approaches to the study of medical consultations. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
43.
OBJECTIVES: Outpatient clinics are increasingly important in medical education. The effect of students on clinic times and patient satisfaction, as well as their own satisfaction, were studied. DESIGN: A prospective, non-randomized, controlled study using adult patient questionnaires, medical student questionnaires and clinic time sheets. SETTING: Two teaching hospital ENT clinics. SUBJECTS: Medical students and adult patients. RESULTS: Three hundred and twenty-five patient questionnaires were collected (77% response), including 135 student encounters. Students did not affect appointment durations (19 min +/- 0.48 (standard error)) except at centre B (35 min +/- 1.1, P < 0.0001) where patient numbers were cut for teaching. Patient satisfaction, generally high, was not affected by students, appointment duration or gender of doctor or patient. It was slightly higher in the lower social classes (rs = 0.20, P = 0. 003) and older patients (rs = 0.17, P = 0.002). Student acceptability scores were not affected by student numbers (up to four), social class or time spent alone with students. They were higher if time was spent alone with the doctor (75.3% +/- 4.9) than not (63.0% +/- 1.8, P = 0.024). Thirty-six per cent of patients preferred to have a student present; only 9% preferred not. Student satisfaction was higher at centre B (73.7% +/- 2.3) where appointments were longer and students spent more time alone with patients than centre A (64.3% +/- 2.3, P = 0.0052). CONCLUSIONS: Clinic appointments are not necessarily longer in the presence of students. When students have the chance to see patients alone during longer consultations, student satisfaction is higher. Patient satisfaction, generally high, is not altered by the presence of students, but patients given time alone with their doctor are more accepting of students. These findings have resource implications for the planning of NHS clinics in teaching hospitals.  相似文献   
44.
OBJECTIVES: The General Medical Council has recommended that medical students should gain more experience in general practice. The study set out to determine patients' reactions to consultations conducted by a medical student alone prior to seeing their GP. DESIGN: A random sample of patients attending general practice surgeries in the Oxford area completed a questionnaire following consultation with a medical student. SETTING: Six general practice teaching surgeries. SUBJECTS: Fifth-year medical students. RESULTS: Of 130 responders 98% experienced no disadvantage in seeing the student; 35% considered that there were advantages in seeing the student; 98% said that they would be prepared to consult with a student again; 85% expressed no concerns about the gender of the student. CONCLUSIONS: The results of this study are very reassuring concerning the acceptability to patients of consulting with medical students and are more favourable than those reported for studies of students being present in consultations by GPs.  相似文献   
45.
The present study investigated the temporal structure of sleep propensity during 48 hours using an ultrashort 7-min sleep/13-min wake cycle. Eight subjects were tested under two experimental conditions of either attempting sleep, or resisting sleep after a monitored night in the laboratory. Electrophysiological recordings were carried out during the 7-min trials. The temporal structure and the overall level of sleepiness of the 48-hour sleep propensity functions calculated from the amount of total sleep in each trial revealed a high within-subjects stability. This was found both across the two days of the study within conditions, and across conditions. Also, diurnal levels of sleepiness were systematically related to nocturnal sleep parameters. Subjects having short nocturnal sleep latencies and higher sleep efficiencies slept more during the day. It is proposed that the structure and level of the sleep propensity function can be used to characterize individuals along two dimensions of somnotypology: "morningness-eveningness" and "sleepy-alert."  相似文献   
46.
The aim of the present study was to investigate in a large group of "drug sophisticated" animals the effect of several doses of oxazepam upon conflict behavior. To this end 43 rats, trained according to the original Geller-Seifter paradigm, were tested with 5 doses (6.25, 12.5, 20.9, 25, and 50 mg/kg IP) of oxazepam. In addition the influence of prior drug experience on the effects of benzodiazepines on punished and unpunished responding was investigated comparing data from the same animals relative to a single oxazepam treatment before and after "drug sophistication." It was found that: (1) after "drug sophistication" oxazepam effect upon the unpunished schedule is decreased, while the disinhibitory action upon punished behavior is increased, unchanged or even decreased; (2) sedative and anticonflict activities of the drug cannot be explained in terms of rate dependency and are independently assessable since, even when unpunished responding is lowered by high doses, the anxiolytic effect is masked in only 27% of the cases; (3) about 20% of the animals appear to be insensitive to the anticonflict effect of oxazepam; (4) the responsiveness to the anxiolytic effect of the drug is related to the shock intensities given during training and to the animal variability under control conditions.  相似文献   
47.
Summary Further analysis of temperature rhythms obtained in an earlier study of 38 subjects subjected to an 8-h eastward transmeridian flight showed that the extent to which the phase of the rhythm was shifted after the flight was related to the phase angle of the pre-flight rhythm. Late peakers shifted more than early peakers, and this difference between the two types was still as large after 12 days in the new time zone as on the first day. Because the phase-shift was an advance one, this meant that the pre-flight individual differences in phase-angle were abolished by the flight, and had not re-appeared by the end of the observation period. It is suggested that this may have been due to an increase in the rigidity of the routine in the post-flight stage of the study, and that a similar effect may also occur in a switch from day to shiftwork.  相似文献   
48.
Steady-state kinetics of imipramine in patients   总被引:1,自引:0,他引:1  
Steady-state plasma level kinetics were studied in 76 patients given imipramine (IP) 150 to 225 mg/day for 2–5 weeks. IP was given in three divided doses at 8.00 a.m., 1.00 p.m. and 5.00 p.m. Plasma concentrations of IP and its active metabolite desipramine (DMI) were determined by quantitative in situ thin-layer chromatography. The plasma levels of IP and DMI showed pronounced flucutations throughout the day with a ratio of about 2 between highest and lowest level. Patients with steady-state levels of IP and/or DMI below 50 g/l reached this within 1 week of treatment. Patients with higher steady-state levels reached steady-state concentrations within 2–3 weeks. There were some intraindividual fluctuations in plasma levels from week to week after steady state had been reached (coefficient of variation: 10–20%). Interindividually, the steady-state levels corrected to a dose of 3.5 mg/kg per day varied considerably: IP: 6–356 g/l, DMI: 24–659 g/l and IP+DMI: 58–809 g/l. The steady-state plasma levels showed a skew distribution that became normal by logarithmic transformation. The IP/DMI ratio ranged from 0.07 to 5.5 with a median value of 0.47. Compared to data from amitriptyline treated patients the IP/DMI ratios had significantly lower median value and larger variation than the corresponding plasma level ratios of amitriptyline/nortriptyline. Several statistically significant differences in steady-state levels between age groups were found. For IP: Women aged 30–39 had lower levels than women aged 20–29, 40–49, and 50–59, and men aged 50–59 and 60–65; men aged 30–39 had lower levels than men aged 60–65. For DMI: Women aged 30–39 had lower levels than women aged 50–59.  相似文献   
49.
根据孕 16~ 2 8周胎儿双顶径、头围、腹围及股骨长等的超声测量值拟合 Rossavik数学模型 [P=c(t) k+ s( t) ]建立胎儿个体生长曲线。结果显示 ,2 0例正常单胎的超声参数与 Rossavik模型的拟合效果好 ,孕 2 8~ 41周胎儿各项参数的模型预测值与实测值比较均无显著差异  相似文献   
50.
面向消费者开展优良药学咨询服务   总被引:2,自引:0,他引:2  
贡庆 《中国药房》2003,14(10):636-637
目的 :为药店开展优良用药咨询服务提出建议。方法 :对消费者进行问卷调查 ,对调查结果进行统计学处理。结果 :大多数消费者需要和认可用药咨询服务 ,并希望通过用药咨询获得医药知识。结论 :药店应积极推行《优良药房工作规范》 ,重视医药健康知识的宣传  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