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   9373篇
  免费   933篇
  国内免费   16篇
耳鼻咽喉   60篇
儿科学   344篇
妇产科学   190篇
基础医学   1211篇
口腔科学   147篇
临床医学   1029篇
内科学   2004篇
皮肤病学   71篇
神经病学   755篇
特种医学   463篇
外国民族医学   5篇
外科学   1238篇
综合类   266篇
现状与发展   1篇
一般理论   15篇
预防医学   1070篇
眼科学   226篇
药学   843篇
中国医学   2篇
肿瘤学   382篇
  2021年   137篇
  2020年   88篇
  2019年   156篇
  2018年   168篇
  2017年   134篇
  2016年   146篇
  2015年   159篇
  2014年   233篇
  2013年   321篇
  2012年   457篇
  2011年   488篇
  2010年   260篇
  2009年   236篇
  2008年   448篇
  2007年   487篇
  2006年   442篇
  2005年   472篇
  2004年   451篇
  2003年   381篇
  2002年   378篇
  2001年   284篇
  2000年   289篇
  1999年   225篇
  1998年   132篇
  1997年   144篇
  1996年   120篇
  1995年   89篇
  1994年   97篇
  1993年   91篇
  1992年   178篇
  1991年   171篇
  1990年   163篇
  1989年   151篇
  1988年   135篇
  1987年   144篇
  1986年   113篇
  1985年   133篇
  1984年   98篇
  1983年   100篇
  1982年   98篇
  1981年   73篇
  1980年   74篇
  1979年   117篇
  1978年   74篇
  1977年   76篇
  1976年   64篇
  1974年   64篇
  1973年   63篇
  1972年   57篇
  1968年   64篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
41.
To better understand adjustment following spinal cord injury (SCI), 106 subjects from two samples (N = 53 each) were administered the SCL-90-R, a symptom checklist, and the Multidimensional Health Locus of Control scales. Sample 1 subjects were admitted for rehabilitation during 1981 to 1982 and sample 2 subjects were admitted during 1984 to 1986. Sample 2 subjects entered rehabilitation programs more quickly after injury and reported more anxiety, phobic anxiety, and hostility than sample 1 subjects. Within each sample, there was no evidence for a relationship between age or time since injury and health beliefs or psychological distress. This study does not support stage theory for adjustment after catastrophic injury, but does suggest the importance of understanding the impact of social policy changes in adjustment following spinal cord injury.  相似文献   
42.
An interactive course in drug information skills developed for pharmacists at a not-for-profit, tertiary-care hospital is described. Faculty members from the area school of pharmacy developed, taught, and evaluated the program. Before the course was developed, pharmacy staff members were asked to rate their drug information skills; the pharmacists' responses indicated their belief that they were not proficient enough in the skills needed in daily practice. The course content and format were refined after 11 pharmacists completed a pilot program. A handbook was developed that contained objectives, session outlines, and literature for each of the six topics chosen for the course. Although the handbook was the primary teaching aid, wall charts and computer demonstrations were also used. Sessions were structured for the needs of adult students by using a small-group discussion format that emphasized the practical relevance of the information and encouraged participants to share personal experiences. Each session was offered on two separate days to facilitate attendance. Those who completed the course received credit for 12 contact hours of continuing education. Of 16 pharmacists enrolled in the course, 11 completed it. An interactive course in drug information skills, developed to meet the needs of hospital pharmacists, was well accepted because it incorporated personal experiences, small-group activities, and flexible scheduling.  相似文献   
43.
OBJECTIVE: The corrosion potential of a dental amalgam restoration is generally determined using a single measurement, even though environmental factors and abrasion can continuously alter the surface state and reactivity of this alloy. It was, therefore, the purpose of this study to determine the maximum variability of the corrosion potential of aged dental amalgam restorations, for 28 days. METHODS: The corrosion potentials of 148 aged dental amalgam restorations in 12 human subjects were measured at t = 0 and 4 h, and 4, 7, 14, 21 and 28 days. Measurements were made with a high impedance voltmeter and a Ag/AgCl micro-reference electrode. The subjects were instructed not to alter their usual eating and oral hygiene routines. RESULTS: Corrosion potential changes occurred throughout the 28 days. They were both positive and negative for the same restoration, and were sometimes very large. Only 4 h after the initial measurement, the absolute value of the corrosion potential changes ranged between 18 and 287 mV for 50% of the restorations. The largest maximum absolute corrosion potential change for each subject's restorations ranged between 85 and 329 mV. Statistical analysis showed that the overall mean maximum absolute corrosion potential change for the subjects' restorations was 74 mV. SIGNIFICANCE: It was shown that the corrosion potential of aged dental amalgam restorations varies substantially over time, and that a single measurement is not representative of short- or long-term electrochemical behavior. This finding has implications regarding the corrosion rate of dental amalgam restorations, particularly those that are part of a galvanic couple.  相似文献   
44.
Over the last three decades an error in performing Finkelstein's test has crept into the English literature in both text books and journals. This error can produce a false-positive, and if relied upon, a wrong diagnosis can be made, leading to inappropriate surgery.  相似文献   
45.
Cervical ripening prior to induction of labor is often necessary for medical complications of pregnancy. We proposed to prospectively determine the safety of administering prostaglandin E2 (PGE2) gel intracervically in an outpatient setting. Four hundred forty-six patients underwent 515 gel procedures as outpatients. Trained perinatal nurses placed 0.5 mg of PGE2, prepared in a standard methylcellulose base, in the intracervical canal. The PGE2 dose was administered every two hours for a total of three doses if labor did not start. The patient was sent home two hours after the last dose if she was not in active labor. Labor started in 90 patients (20%) during the gel procedure; they were admitted to the labor-and-delivery unit. The remaining patients were discharged. Eighty-eight patients (20%) were later admitted in active labor prior to scheduled induction. One patient (0.02%) was found to have occasional prolonged decelerations on admission and underwent a cesarean section two hours after admission; the Apgar scores were 8 and 9 and the arterial pH, 7.21. Hyperstimulation with excessive intrauterine activity caused significant deceleration of the fetal heart rate in four patients (0.8%), two of whom required transfer to the labor-and-delivery unit but none of whom needed a cesarean section for fetal distress. PGE2 gel can be administered safely intracervically as an outpatient procedure by trained perinatal nurses.  相似文献   
46.
The processing of antigens delivered as DNA vaccines   总被引:2,自引:0,他引:2  
Summary: The ability of DNA vaccines to provide effective immunological protection against infection and tumors depends on their ability to generate good CD4+ and CD8+ T‐cell responses. Priming of these responses is a property of dendritic cells (DCs), and so the efficacy of DNA‐encoded vaccines is likely to depend on the way in which the antigens they encode are processed by DCs. This processing could either be via the synthesis of the vaccine‐encoded antigen by the DCs themselves or via its uptake by DCs following its synthesis in bystander cells that are unable to prime T cells. These different sources of antigen are likely to engage different antigen‐processing pathways, which are the subject of this review. Understanding how to access different processing pathways in DCs may ultimately aid the rational development of plasmid‐based vaccines to pathogens and to cancer.  相似文献   
47.
Homocysteine and bone loss in epilepsy.   总被引:1,自引:0,他引:1  
Epidemiological studies reveal fracture incidence in epilepsy is twice that of the normal population. Much interest has been focused on Vitamin D, however, considering mixed results on non-enzyme inducing anti-epileptic drugs (AEDs) and bone mineral density (BMD) additional metabolic effects may be to blame. AEDs increase serum homocysteine (s-Hcy) by lowering blood folate levels. An association between elevated homocysteine, BMD and increased fracture incidence has been found in non-epilepsy populations. Additionally, folate and Vitamin B12 levels are independently related to bone mineral density in various non-epilepsy populations. This study supports previous research, which found elevated s-Hcy in subjects taking AEDs and that bone loss is related to the use of enzyme-inducing AEDs and changes in alkaline phosphatase. By one-way ANOVA, subjects on phenytoin monotherapy had significantly higher levels of s-Hcy than those on other AEDs (F=5.89, p=.016). Regression analyses revealed homocysteine, fracture history, length of years on AEDs, ethnicity were predictors of spine T scores. Weight and BMI were predictors of both BMD and DEXA T scores. Use of enzyme-inducing AEDs was a negative predictor of spine BMD and T scores, while phenytoin monotherapy was a positive predictor of spine BMD. Lamotrigine was found to be a negative predictor of spine T score. Ambulatory status, menopause and alcohol consumption were predictors of BMD but not T scores. In this study, persons with epilepsy who take nutritional supplementation have 25% lower s-Hcy levels than those who do not. Supplementation continues to be important in preventative epilepsy care.  相似文献   
48.
Recent years have witnessed increased antipsychotic treatment of children despite limited long‐term safety data in children. In this study, motor side effects associated with the use of antipsychotic drugs in children were examined in a sample of pediatric psychiatric patients. Child and adolescent psychiatric patients receiving antipsychotics (most were on atypicals) for 6 months or longer (n = 118) were compared with antipsychotic‐naïve patients (n = 80) with similar age, sex ratio, and diagnoses. Only 19% of patients on antipsychotics had ever experienced psychotic symptoms. Eleven children (9%) on antipsychotics exhibited dyskinesia, when compared with 0 in the naïve group (P = 0.003, Fisher's exact test). Nine of 62 African–American children (15%) on antipsychotics exhibited dyskinesia, when compared with only 4% (2 of 52) of European–American children (P = 0.003, Fisher's exact test). Children treated with antipsychotic drugs might experience a significant risk of dyskinesia even when treated only with atypical antipsychotics. Ethnicity might also be a risk factor for dyskinesia in children. Side‐effect profile of the atypical antipsychotic drugs in children may be much different than that in adults. © 2007 Movement Disorder Society  相似文献   
49.
50.
The origin of image artifacts in an off-resonance spin-locking experiment is shown to be imperfections in the excitation flip angle. A pulse sequence for off-resonance spin locking is implemented that compensates for imperfections in the excitation flip angle through an off-resonance rotary echo. The off-resonance rotary echo alternates the frequency offset and phase of the RF transmitter during two spin-locking pulses of equal duration. The underlying theory is detailed, and MR images demonstrate the effectiveness of the technique in agarose gel phantoms and in in vivo human brain at 3T.  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