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   1170232篇
  免费   77568篇
  国内免费   2117篇
耳鼻咽喉   16167篇
儿科学   37499篇
妇产科学   30965篇
基础医学   166182篇
口腔科学   31969篇
临床医学   102598篇
内科学   224549篇
皮肤病学   26398篇
神经病学   90104篇
特种医学   46519篇
外国民族医学   223篇
外科学   176725篇
综合类   23293篇
现状与发展   2篇
一般理论   315篇
预防医学   80411篇
眼科学   26080篇
药学   93754篇
  10篇
中国医学   3328篇
肿瘤学   72826篇
  2021年   9397篇
  2019年   9500篇
  2018年   13416篇
  2017年   10487篇
  2016年   11784篇
  2015年   13221篇
  2014年   17820篇
  2013年   25866篇
  2012年   35464篇
  2011年   37431篇
  2010年   22256篇
  2009年   20695篇
  2008年   34389篇
  2007年   36791篇
  2006年   37195篇
  2005年   35273篇
  2004年   34288篇
  2003年   32964篇
  2002年   31966篇
  2001年   63547篇
  2000年   65020篇
  1999年   53791篇
  1998年   13546篇
  1997年   11845篇
  1996年   11776篇
  1995年   11078篇
  1994年   10013篇
  1993年   9499篇
  1992年   39479篇
  1991年   37977篇
  1990年   37204篇
  1989年   35691篇
  1988年   32162篇
  1987年   31156篇
  1986年   29368篇
  1985年   27488篇
  1984年   19939篇
  1983年   16793篇
  1982年   9260篇
  1979年   17608篇
  1978年   11847篇
  1977年   10602篇
  1976年   9181篇
  1975年   10512篇
  1974年   12151篇
  1973年   11741篇
  1972年   11184篇
  1971年   10480篇
  1970年   9611篇
  1969年   9292篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
992.
Sleep spindles are an EEG sign of light sleep under physiological conditions. We reported the simultaneous occurrence of sleep spindles and alpha activity in the waking EEG in 12 patients with a mean age of 59.0 years. Most of the patients were diagnosed as cerebrovascular disorders such as cerebral arteriosclerosis, transient ischemic attack and vascular dementia. The mean alpha frequency in the presence of WSA significantly decreased by 1.5 Hz. The frequency and spatial distribution of waking spindle activity were similar to those of sleep spindles. In our cases, at least the two factors of cerebrovascular involvement and older adults were considered to be primarily responsible for the intrusion of sleep spindles into wakefulness (presumably a state close to very light drowsiness) due possibly to the instability of sleep-waking cycle regulation.  相似文献   
993.
In six hundred and six consecutive patients undergoing coronary artery bypass grafting (CABG) within the past 17 years (May 1974 to March 1991), repeated CABG were performed on 10 patients (1.65%). The main reasons for repeated CABG were graft failure (GF) in 8, progression of native disease (NP) in 5 and incomplete revascularization (IR) in 3 patients. The incidence of GF was high either within a half year or around 5 years after CABG. Although all patients survived from reoperation, four patients continued to have mild angina pectoris. When the recurrence of angina is noted after CABG, coronary arteriography and if necessary PTCA should be done as soon as possible. If a second surgery is inevitable, maximum utilization of arterial graft and accomplishment of complete revascularization are emphasized.  相似文献   
994.
Ten patients with osteosarcomas and rotation plasties made themselves available for a psychological survey. The time elapsed after their operations was between two and ten years, giving an average of six years. All patients were free of tumours at the time of the follow-up examination. Both in personal interviews and in psychological tests, it was possible to observe a very positive development of these patients' attitudes. Contributory factors in this context were discussions with the doctors administering treatment, the cheerful atmosphere of the hospital and the nursing staff, the physicotherapists and ergotherapists, and the excellent social support which all those interviewed also received from their relatives. Continuous positive motivation, a favourable social dialogue and patients' ability to control their own lives would appear to be the key factors in helping patients to come to terms with their illness.  相似文献   
995.
996.
After treatment with two lateral percutaneous pins, 80 children with grade II-III supracondylar elbow fractures were reviewed. The result was good in 55 patients (68%) and was the same for extension- and flexion-type injuries. These patients had less than 10 degrees change in carrying angle and less than 20 degrees total change in range of motion. This method eliminates risk of iatrogenic injury to the ulnar nerve but is technically very demanding. Redisplacement, joint penetration, and damage to the capitellar side of growth plate can be avoided only by positioning the pins divergently.  相似文献   
997.
The short section of the urethra that passes through the urogenital diaphragm is termed the membranous urethra. It is accompanied by several vessels and nerve fibers. In surgery on the membranous urethra the perineal body is of crucial importance, and precise knowledge of the course of the urethra through the pelvic floor is essential. Furthermore, the relationship between the membranous urethra and its accompanying structures is of great importance. These include the branches of the internal pudendal artery, the prostatic venous plexus and the cavernous nerves coursing ventrally from the pelvic plexus. The nerves supplying the membranous urethra were studied in fetuses with the help of a magnifying lens. The results of the dissections are documented by histological sections, photographs and paintings.  相似文献   
998.
Résumé L'utilisation de matériaux d'ostéosynthèse biodégradables a l'avantage d'éviter la réintervention pour extraire le matériel. Les biomatériaux de polymères polyglycolides ont été expérimentés sur plus de 3 600 animaux de laboratoire avant leur introduction en pratique clinique. Depuis 1984 nous les avons utilisés comme matériau d'ostéosynthèse dans près de 1 700 cas parmi lesquels 880 cas de fracture malléolaire, 226 cas d'ostéotomie en chevron pour hallux valgus, 65 cas de fracture de la tête radiale et 54 cas de fracture de l'olécrane. Parmi les 800 premiers cas traités par broches biodégradables nous avons obtenu des résultats favorables et sans incidents dans 91 pour cent des cas. Il y eut 7 cas de fixation défaillante nécessitant une réintervention. Il y a eu 7 cas d'infection superficielle et 3 cas d'infection profonde. Nous avons observé la formation d'une collection séreuse sous-cutanée sans influence sur le résultat radiologique ou clinique dans 52 cas (6,5 %). Au vue de ces résultats et compte tenu des avantages économiques et psychologiques des matériaux biodégradables (pas de réintervention), on peut penser que l'usage de biomatériaux rivalise favorablement avec l'usage de matériaux conventionnels dans certains types d'ostéosynthèse.
Utilization of biodegradable implants in the surgical treatment of fractures and osteotomies
Summary The utilization of biodegradable implants instead of metals in orthopaedic surgery abolishes the need to remove the fixation material. For this study biodegradable rods and screws of self-reinforced polyglycolide, polylactide and lactide-glycolide copolymer were developed and manufactured. The clinical introduction of these implants was preceded by thorough experimental studies with 3 600 animals. From November 1984 the developed biodegradable method of osteofixation was used in 1 700 operations. These included 880 displaced malleolar fractures, 226 chevron-osteotomy for hallux valgus, 65 displaced fracture of the radial head, 54 displaced frature of the olecranon and other fresh fractures or orthopaedic operations. In the first 800 cases operated on using self-reinforced polyglycolide rods the postoperative course was uneventful (91%). Because of failure in the fixation reoperation was needed in 7 cases. A superficial wound infection was observed in 7 cases, deep infection in 3 and transient fluid accumulation in 52 cases (6,5%). Fluid accumulation did not influence the radiological or clinical end-result. The advantages of biodegradable fixation are many-sided. There is a costbenefit and clinical capacity is free for other use, and psychological advantages must be emphasised because removal of implants is not needed. The over all results of this study were considered favourable.
  相似文献   
999.
1000.
A modified enzyme immunoassay based on adsorption of antihepatitis A virus (HAV) IgG-HRPO conjugate and monoclonal antibodies to HAV were used to investigate antigenic differences between mature HAV virions and subviral particles with different buoyant densities in CsCl produced in HAV-infected cells. The mature virions (1.34 g/cm3) appeared to have common antigenic determinants with subviral particles (1.20, 1.27, and 1.30 g/cm3) and possess some additional determinants. Nevertheless, both subviral particles and mature virions induced antibodies capable of neutralizing HAV infectivity in tissue culture.  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