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   19581篇
  免费   1874篇
  国内免费   79篇
耳鼻咽喉   259篇
儿科学   696篇
妇产科学   520篇
基础医学   2960篇
口腔科学   368篇
临床医学   2292篇
内科学   3806篇
皮肤病学   215篇
神经病学   1505篇
特种医学   816篇
外国民族医学   3篇
外科学   2464篇
综合类   522篇
一般理论   25篇
预防医学   2058篇
眼科学   266篇
药学   1596篇
  1篇
中国医学   6篇
肿瘤学   1156篇
  2021年   282篇
  2019年   275篇
  2018年   291篇
  2017年   209篇
  2016年   241篇
  2015年   299篇
  2014年   426篇
  2013年   617篇
  2012年   840篇
  2011年   920篇
  2010年   493篇
  2009年   426篇
  2008年   758篇
  2007年   828篇
  2006年   801篇
  2005年   807篇
  2004年   728篇
  2003年   668篇
  2002年   676篇
  2001年   603篇
  2000年   646篇
  1999年   539篇
  1998年   268篇
  1997年   226篇
  1996年   243篇
  1995年   232篇
  1994年   195篇
  1993年   198篇
  1992年   490篇
  1991年   491篇
  1990年   461篇
  1989年   427篇
  1988年   399篇
  1987年   417篇
  1986年   415篇
  1985年   415篇
  1984年   317篇
  1983年   268篇
  1982年   205篇
  1981年   167篇
  1980年   164篇
  1979年   306篇
  1978年   225篇
  1977年   200篇
  1976年   167篇
  1975年   177篇
  1974年   181篇
  1973年   189篇
  1972年   168篇
  1971年   163篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
Students in grades 1 through 6 were assessed on 11 ocular functions. A multivariate correlation was made between these ocular functions and the students' reading ability, as measured on the Stanford Achievement Test. There were no significant multivariate correlations between the ocular functions and the students' reading ability. It was concluded that for students with small heterophorias and no significant refractive errors, a relationship did not exist between ocular functions and reading ability.  相似文献   
62.
We describe a case of giant cavernous haemangioma of the liver with disseminated intravascular coagulopathy (Kasabach-Merritt syndrome) which was cured by orthotopic liver transplant.A 47 year old man presented with bleeding and tender massive hepatomegaly after tooth extraction. Investigations showed disseminated intravascular coagulopathy and a giant hepatic haemangioma involving both lobes of the liver. Initial treatment failed to resolve the coagulopathy and liver resection was attempted. At laparotomy the turnout was unresectable and the only option for cure was to offer a liver transplantation. The orthotopic liver transplant was performed 20 days after initial laparotomy. Subsequently, all coagulation parameters returned to normal and the patient remains well after 12 months. Orthotopic liver transplant can be considered for giant hepatic haemangioma with Kasabach-Merritt syndrome when resection is necessary and a partial hepatectomy is not technically feasible.  相似文献   
63.
The aim of the study was to distinguish infection from inflammation in patients with suspected infection using technetium-99m Infecton. Ninety-nine patients (102 studies) referred for infection evaluation underwent imaging with 400 MBq99mTc-Infecton at 1 and 4 h. Most patients had appropriate microbiological tests and about half (56) had radiolabelled white cell scans as well. No adverse effects were noted in any patient. The clinical efficacy of99mTc-Infecton depended in part on whether imaging was undertaken during intibiotic therapy for infection or not. In consultation with the microbiologist, 5–14 days of appropriate and successful antibiotic therapy was considered adequate to classify some results as true-negatives. The figures for sensitivity and specificity of99mTc-Infecton for active or unsuccessfully treated infection were 83% and 91% respectively. It is concluded that99mTc-Infecton imaging contributed to the differential diagnosis of inflammation. It is being used as the first imaging modality when bacterial infection is suspected.  相似文献   
64.
The aetiopathogenesis of haemorrhagic shock encephalopathy syndrome (HSES) remains unclear and after concern that a novel environmental agent was the cause, the British Paediatric Association and the Public Health Laboratory Service Communicable Disease Surveillance Centre in 1983 initiated surveillance of this condition in the British Isles. After 1986 cases were ascertained via the British Paediatric Surveillance Unit 'active' reporting scheme; this report presents the findings for 1985-8. Sixty five patients were reported, of whom 52 satisfied the criteria for inclusion. Of those whose outcome was known, 24 (46%) died, 18 had severe neurological damage, and six survived apparently intact. Epidemiological features of note were: the median age of 15 weeks (range 3-140); statistically significant clustering of admission times suggesting a peak onset period at night; lack of geographic clusters, of secular trends and, except for a slight excess in winter months, of seasonality. Clinical and pathological features followed a highly consistent pattern, suggesting that HSES is an individual clinical entity distinguishable from conditions with similar presentations, such as septicaemia and Reye's syndrome. There was no microbiological or epidemiological evidence to support the emergence of a novel environmental agent. Many of the features of HSES were, however, the same as those described in heat stroke and we suggest that the two conditions are the same even though there is usually no history of overt overheating.  相似文献   
65.
66.
An attempt was made to develop a model of chronic renal disease in the rat through repeated administration of a nephrotoxin specific for proximal tubular epithelium. Mercuric chloride was administered by subcutaneous injection in gradually increasing amounts over a period of 21 weeks. The dose ranged from 1.125 mg/kg once a week to 2.0 mg/kg twice a week. Measured parameters of renal function include plasma urea nitrogen, plasma creatinine, 24-hour urine output volume, and 24-hour urinary protein excretion. When compared to their own pretreatment values and those of the age/weight-matched control animals, the mercuric chloride-treated rats exhibited no significant abnormalities in these parameters of kidney function with the exception of a mild proteinuria at 21 weeks. Light microscopic examination of the kidneys of the mercury-treated rats revealed mild tubular, interstitial, and glomerular lesions which were significantly worse than those in the kidneys of the controls. This study demonstrates the ability of the kidney to sustain a considerable degree of resistance to inorganic mercury toxicity when exposure is continuous over a prolonged period of time. It also demonstrates the inability of commonly measured clinical laboratory parameters of kidney function to identify the effects of chronic mercuric chloride toxicity in the rat.  相似文献   
67.
68.
69.
Phosphonoacetic acid (PAA, 1) was coupled with various acyclonucleosides, 2'-deoxyuridines, cytidines, and arabinosyluracils, with 2,4,6-triisopropylbenzenesulfonyl chloride (TPS) or dicyclohexylcarbodiimide (DCCI) as condensing agents, to give a range of phosphonate esters. The carboxylic ester linkage of PAA to the 5'-position of 5-bromo-2'-deoxyuridine (BUdR, 3) was achieved via the mixed anhydride formed from (diethylphosphono)acetic acid and trifluoroacetic anhydride. Phosphonoformic acid (PFA, 2) was coupled with BUdR by using the DCCI method to give the phosphonate ester. Of these compounds only phosphonate esters in the 2'-deoxyuridine series showed significant activity against herpes simplex virus types 1 and 2. The BUdR-PAA derivative and the BUdR-PFA derivative were highly active, especially the latter, which was more active than the parent nucleoside BUdR against the type 2 virus. The active compounds may exert their effects by extracellular or intracellular hydrolysis to the corresponding antiviral agents, but an intrinsic component of antiviral activity may also be involved.  相似文献   
70.
Examined the effects of two instructional methods on language generalization and longterm retention in 23 adults with autism and severe to profound mental retardation. Analog language teaching employed discrete trials in a controlled setting concentrating on discrimination and identification of materials. Natural language teaching emphasized instruction through interactions that occurred incidentally to training students in the use of materials to perform functional tasks. Assessments were conducted under conditions favoring analog teaching to assure against partiality toward natural language teaching. Under such disadvantageous conditions, the methods of natural language teaching would be supported by results showing either no difference or an advantage in their favor. Both techniques increased initial and long-term generalization though the results suggest no relative superiority for either method under these assessment conditions. A significant interaction was found between prior functioning level and sequence of instruction. Because natural language teaching has many strengths, few drawbacks, and produces equal generalization and retention under disadvantageous conditions, it is strongly supported as preferable for people with autism and mental retardation.The authors acknowledge the important assistance provided by the following people: the staff and management of the Behavior Development and Learning Center at CSH/DC directed by Israel Perel, Lisa Kramer, Steve Hafferkamp, James Lowdermilk, and, finally, and especially, to the participants themselves.  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