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   3287042篇
  免费   232480篇
  国内免费   5794篇
耳鼻咽喉   47146篇
儿科学   104250篇
妇产科学   90938篇
基础医学   477749篇
口腔科学   93596篇
临床医学   292480篇
内科学   632028篇
皮肤病学   73549篇
神经病学   259696篇
特种医学   125213篇
外国民族医学   894篇
外科学   499324篇
综合类   71142篇
现状与发展   16篇
一般理论   1189篇
预防医学   248296篇
眼科学   78061篇
药学   246126篇
  15篇
中国医学   6806篇
肿瘤学   176802篇
  2018年   34490篇
  2017年   26354篇
  2016年   29480篇
  2015年   33130篇
  2014年   46746篇
  2013年   70809篇
  2012年   96090篇
  2011年   102250篇
  2010年   60922篇
  2009年   57933篇
  2008年   96738篇
  2007年   104017篇
  2006年   104863篇
  2005年   101902篇
  2004年   97900篇
  2003年   94639篇
  2002年   92077篇
  2001年   148902篇
  2000年   152790篇
  1999年   128999篇
  1998年   37133篇
  1997年   32789篇
  1996年   32450篇
  1995年   30775篇
  1994年   28470篇
  1993年   26828篇
  1992年   100507篇
  1991年   98088篇
  1990年   95954篇
  1989年   92904篇
  1988年   85921篇
  1987年   84504篇
  1986年   79858篇
  1985年   76596篇
  1984年   57040篇
  1983年   48635篇
  1982年   29102篇
  1981年   26252篇
  1979年   53442篇
  1978年   38300篇
  1977年   32491篇
  1976年   30466篇
  1975年   33620篇
  1974年   40138篇
  1973年   38531篇
  1972年   36487篇
  1971年   34434篇
  1970年   32152篇
  1969年   30728篇
  1968年   28418篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Twenty two patients (age range: 1 month to 11 years) were treated for congenital diaphragmatic defects (excluding hiatus hernia) in the six year period 1983-8. Presenting features were failure to thrive (n = 7), abdominal pain and vomiting (n = 4), chronic respiratory symptoms (n = 3), and inability to wean from ventilatory support (n = 3). The defect was an incidental finding in five patients. Operative repair was performed with no mortality or serious postoperative morbidity. Dramatic improvement occurred in 15 of the 17 symptomatic patients. Awareness of the differential diagnosis should avoid delay in diagnosis or inappropriate treatment. Surgical correction is strongly recommended in all cases.  相似文献   
992.
993.
From October to December 1984, examination has been carried out on Salmonella-typhi cultures from blood, bone marrow, faeces and urine of 43 patients suffering from suspected typhoid fever treated in the Department of Child Health, Medical School/Hasan Sadikin General Hospital, Bandung. It was apparent that among these 43 patients, 51.2% were males and 48.8% females. The greater number of them were more than 5 years old (64.4%). The results of Salmonella-typhi cultures were obtained from 65% of the patients, consisting of 65% positive cultures from bone-marrow and 40% positive cultures from blood that showed a statistically significant difference (p less than 0.05). Likewise, the time for matter-sampling for the examinations was based on the culture results, both on blood-culture and that of bone-marrow, statistically a significant was found (p less than 0.05), whereas the results of cultures based on previous vaccination history and the administration of chloramphenicol prior to treatment did not differ significantly. It was obviously clear that the results of bone-marrow culture were more successful compared to those from blood culture, so that it should necessarily be emphasized, as to these examinations on culture from each patient with suspected typhoid fever, especially those patients hospitalized during the third week of their illness.  相似文献   
994.
Five cases of unilateral vocal cord paralysis/paresis were diagnosed following extracorporeal membrane oxygenation for newborn respiratory failure. All were right sided and transient in nature. None of the five patients had other findings commonly associated with vocal cord palsy. The extracorporeal membrane oxygenation procedure requires surgical dissection in the carotid sheath on the right side of the neck, an area immediately adjacent to both the vagus and recurrent laryngeal nerve. It is speculated that vocal cord paralysis in these infants was acquired as a result of the extracorporeal membrane oxygenation cannulation. Although the vocal cord paralysis resolved in all cases, two patients had difficult courses after extracorporeal membrane oxygenation. Therefore, laryngoscopic examination should be considered for patients after extracorporeal membrane oxygenation.  相似文献   
995.
996.
The incidence and mortality of acute epiglottitis were retrospectively analysed covering a 12-year period, 1975-1987. The diagnosis was made by the laryngoscopic findings in 95% of patients. Based on 902 hospitalized patients, a mean annual incidence of 4.9 cases per 100,000 children and adults was found. Although adult patients predominated (60%), the incidence was far higher in children, 13.8 per 100,000 compared with 3.9 per 100,000 in adults. Two peaks in incidence were identified, one for the youngest children, and the second for young adults (15-29 years). Over the years the incidence varied little in adults, but decreased significantly in children over the last 6 years studied. The data presented indicate acute epiglottitis to be a more frequent disorder than previously believed but with less risk of a fatal outcome. The mortality rate was below 1% in children and adults and the annual incidence of death from acute epiglottitis was estimated at 0.5 cases per million. The primary admission of these patients to ENT units seems to be the single factor having the most powerful impact on mortality.  相似文献   
997.
Tumor material from 91 patients with squamous cell carcinoma of the head and neck was transplanted subcutaneously in athymic nude mice. In the first (man to mouse) passage, the calculated mean probability of tumor take in a single mouse was 11%. The probability of growth in the first passage was significantly better for moderately and poorly differentiated tumors than for well-differentiated tumors. Also, the implantation of lymph node material resulted in a significantly better tumor take rate than material taken from a primary tumor. Transplantability was not dependent on the following characteristics: localization, T or N stage of the tumor, or the sex of the patients. Once growth was established, all variables studied had no influence on the probability of growth in the subsequent mouse passages. A relationship between tumor growth in nude mice and patient prognosis could not be found. When transplanting head and neck squamous cell carcinoma in nude mice, it has to be recognized that some tumor characteristics will influence the success of tumor growth.  相似文献   
998.
To determine whether well-appearing children found incidentally to be neutropenic are at risk for an infectious complication, 44 consecutive months of hematology laboratory records were reviewed. One hundred nineteen patients had medical record documentation regarding clinical course, serial white blood cell counts, and the absence of serious infections, chronic illnesses, or a family history known to be associated with neutropenia. The median duration of documented neutropenia was 13 days (range, 1 to 491 days). Infectious complications occurred in 4 of the 36 patients who had neutropenia for more than 30 days (2 with stomatitis, 1 with cellulitis, and 1 with pneumonia) but in none with shorter durations of neutropenia. There were no significant associations between the development of an infectious complication and either the initial absolute neutrophil count or the lowest documented absolute neutrophil count, nor was there a correlation between the initial absolute neutrophil count and the duration of neutropenia. These data indicate that infectious complications occur in otherwise well children with unexplained neutropenia that persists, but these infections are infrequent and usually are superficial.  相似文献   
999.
Usher syndrome: clinical findings and gene localization studies   总被引:3,自引:0,他引:3  
The issue of genetic heterogeneity is a critical problem in the localization of the gene(s) for Usher syndrome. Based on the data obtained on families studied to date, the differences between type I and type II Usher syndrome appear quite distinct with regard to auditory and vestibular function. Although the majority of families can be confidently diagnosed as typical type I or type II, clinical investigations revealed four families with findings that did not fit into either of the two more common subtypes. These findings emphasize the critical importance of an in-depth clinical analysis concomitant with the linkage investigation to assure accurate subtyping of Usher syndrome. Based on an analysis of only those families with definite type I or type II Usher syndrome, approximately 17% of the genome can be excluded as a potential site of the gene for type I, and 14% can be excluded as the site for the type II gene. This study will continue until the Usher gene(s) is successfully localized.  相似文献   
1000.
This paper suggests that like ethanol, methanol also produces certain changes in the steady state level of monoamines in hypothalamus and striatum of albino rats. Though, the toxic manifestations of methanol are attributed to the metabolic end product of methanol viz. formic acid by several workers, we report here that the methanol-induced brain monoamine changes, at least, could be attributed to the direct action of methanol rather than to its metabolic end products like formaldehyde or formate. Studies in the steady state level of rat brain monoamines have shown that after methanol administration (3 g/kg), there is severe depletion of dopamine level in striatum but a significant increase in the level of dopamine, serotonin and 5-hydroxy indole acetic acid in hypothalamus. At the same time, norepinephrine and epinephrine levels are reduced in hypothalamus as well as in striatum. These effects do not seem to be induced by metabolic acidosis. The changes in monoamine levels are very well correlated with the blood and brain level of methanol as evidenced by maintaining a higher methanol level either by simultaneous administration of ethanol or by blocking methanol metabolism by pretreatment with 4-methyl pyrazole and 3-amino-1,2,4-triazole. It is thus postulated that monoamine changes induced by methanol appear to be the direct effect of methanol per se on the monoaminergic neuronal membranes.  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