全文获取类型
收费全文 | 96152篇 |
免费 | 9247篇 |
国内免费 | 182篇 |
专业分类
耳鼻咽喉 | 1382篇 |
儿科学 | 3065篇 |
妇产科学 | 1901篇 |
基础医学 | 13661篇 |
口腔科学 | 2360篇 |
临床医学 | 11403篇 |
内科学 | 17088篇 |
皮肤病学 | 1573篇 |
神经病学 | 8022篇 |
特种医学 | 3413篇 |
外国民族医学 | 11篇 |
外科学 | 13172篇 |
综合类 | 1871篇 |
一般理论 | 88篇 |
预防医学 | 10659篇 |
眼科学 | 2158篇 |
药学 | 7782篇 |
1篇 | |
中国医学 | 88篇 |
肿瘤学 | 5883篇 |
出版年
2021年 | 1308篇 |
2020年 | 852篇 |
2019年 | 1322篇 |
2018年 | 1593篇 |
2017年 | 1171篇 |
2016年 | 1249篇 |
2015年 | 1447篇 |
2014年 | 1907篇 |
2013年 | 3066篇 |
2012年 | 4173篇 |
2011年 | 4488篇 |
2010年 | 2403篇 |
2009年 | 2288篇 |
2008年 | 3872篇 |
2007年 | 4227篇 |
2006年 | 4112篇 |
2005年 | 4206篇 |
2004年 | 3936篇 |
2003年 | 3704篇 |
2002年 | 3625篇 |
2001年 | 2960篇 |
2000年 | 3066篇 |
1999年 | 2746篇 |
1998年 | 1257篇 |
1997年 | 1042篇 |
1996年 | 1027篇 |
1995年 | 938篇 |
1994年 | 913篇 |
1993年 | 865篇 |
1992年 | 2265篇 |
1991年 | 2178篇 |
1990年 | 2047篇 |
1989年 | 2023篇 |
1988年 | 1899篇 |
1987年 | 1896篇 |
1986年 | 1821篇 |
1985年 | 1802篇 |
1984年 | 1518篇 |
1983年 | 1407篇 |
1982年 | 1001篇 |
1981年 | 849篇 |
1980年 | 777篇 |
1979年 | 1319篇 |
1978年 | 991篇 |
1977年 | 858篇 |
1976年 | 810篇 |
1975年 | 799篇 |
1974年 | 959篇 |
1973年 | 858篇 |
1972年 | 826篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
K A Burkman R W Gaines S R Kashani R D Smith 《Archives of physical medicine and rehabilitation》1988,69(2):132-134
Herpes zoster probably occurs more often than generally thought. Since it produces a radicular distribution of pain, it should be included in the differential diagnosis of radiculopathy. A case is presented in which evaluating the radicular low back pain before the characteristic rash appears was misleading. Careful history-taking concerning the exact nature of the pain and sensory changes is needed to differentiate between zoster and radiculopathy, if no rash is evident. 相似文献
12.
David A. Hughes Graham C. Smith Joyce E. Davidson Anna V. Murphy T. James Beattie 《Pediatric nephrology (Berlin, Germany)》1996,10(4):445-447
. Neutrophil-mediated tissue damage has been implicated in the pathogenesis of diarrhoea-associated haemolytic uraemic syndrome
(D+ HUS). This study evaluates priming and activation of the neutrophil oxidative burst in D+ HUS using chemiluminescent techniques.
Peripheral blood neutrophils from 11 children with acute D+ HUS were examined. No difference was found in the oxidative burst
of neutrophils from patients and controls. Serum elastase levels were measured in 8 patients and found to be significantly
elevated. Although elastase results suggest neutrophil activation, chemiluminescence studies do not confirm this in the peripheral
blood neutrophil. This does not support a significant role for circulating agents in priming and activating the peripheral
blood neutrophil.
Received August 17, 1995; received in revised form and accepted November 27, 1995 相似文献
13.
Segregation analysis of leprosy in families of northern Thailand 总被引:4,自引:0,他引:4
Sixty-three families with multiple instances of leprosy were identified through a major leprosy treatment center in northern Thailand. Complex segregation analyses for single major genes or polygenic inheritance were performed using the maximum-likelihood routine POINTER to determine the most likely etiologic model of genetic susceptibility. Liability differences between men and women were considered in these models. When individuals were considered to be affected because they had any form of leprosy, a generalized major gene model with nearly dominant parameters on the liability scale, but additive penetrances, was found to be the most likely. When only those individuals who had tuberculoid forms of leprosy were considered to be affected, a recessive model was found to be the most likely; however, the discrimination between various models was poor. Further analyses are necessary to delineate genetic mechanisms to explain these apparently divergent results. In particular, methods of testing two locus models should be considered. 相似文献
14.
Peter E Murray Thomas W Smyth Imad About Remeille Remusat Jean-Claude Franquin Anthony J Smith 《Journal of dentistry》2002,30(1):29-36
OBJECTIVES: The incidence of bacterial microleakage, pulp inflammation and necrosis associated with dentine etching treatments prior to restoration are not known. Consequently, to resolve some of the controversy surrounding the effects and importance of vital dentine etching, the authors investigated these factors. METHODS: 110 standardised class V cavities were cut into buccal dentine, without exposing the pulp of teeth scheduled for extraction for orthodontic reasons. Cavities were either left unetched, or etched with the non-equivalent treatments of phosphoric acid gel for 60s or Ethylenediaminetetraacetic acid (EDTA) for 30s, prior to placement of composite resin. Teeth were collected and pulp responses were evaluated according to ISO guidelines, using pathohistomorphometric analysis and ANOVA statistics. RESULTS: Etching was found to be correlated to bacterial microleakage (p=0.0001) and tertiary dentine formation (p=0.0023). Bacterial microleakage was correlated to inflammatory activity (p=0.0001). The frequency of bacterial microleakage was: no etching (65%), EDTA (51%) and phosphoric acid (PA) (20%). SIGNIFICANCE: Vital dentine etching treatment is of extreme importance for the placement of RC to minimise bacterial microleakage. PA etching proved to be more effective at preventing bacterial microleakage than non-etching, and etching with EDTA. 相似文献
15.
B. Bogin P. Smith A.B. Orden M.I. Varela Silva J. Loucky 《American journal of human biology》2002,14(6):753-761
Maya families from Guatemala migrated to the United States in record numbers from the late 1970s to the early 1990s. Births to Maya immigrant women have created a sizable number of Maya American children. The height and sitting height of 5 to 12 years children (n = 431) were measured in 1999 and 2000. Leg length was estimated and the sitting height ratio was calculated. These data were compared with a sample of Maya children living in Guatemala measured in 1998 (n = 1,347). Maya American children are currently 11.54 cm taller and 6.83 cm longer‐legged, on average, than Maya children living in Guatemala. Consequently, the Maya Americans have a significantly lower average sitting height ratio (i.e., relatively longer legs in proportion to length of the head and trunk) than do the Maya in Guatemala. These results add support to the hypothesis that both the height and body proportions of human populations are sensitive indicators of the quality of the environment for growth. Am. J. Hum. Biol. 14:753–761, 2002. © 2002 Wiley‐Liss, Inc. 相似文献
16.
R J Smith 《The British journal of ophthalmology》1989,73(7):481-482
17.
Inborn errors of the urea cycle are an important cause of hyperammonaemia throughout childhood, and are associated with high morbidity and mortality rates. If they are diagnosed early and treated appropriately, the outcome for affected children is significantly improved. 相似文献
18.
Alpha-adrenoreceptor reagents. 4. Resolution of some potent selective prejunctional alpha 2-adrenoreceptor antagonists 总被引:1,自引:0,他引:1
A P Welbourn C B Chapleo A C Lane P L Myers A G Roach C F Smith M R Stillings I F Tulloch 《Journal of medicinal chemistry》1986,29(10):2000-2003
The resolution of three 2-substituted derivatives of idazoxan is described. The enantiomers show large separations in activity in a variety of in vitro and in vivo tests, and the active isomers are all potent and selective antagonists at the alpha 2-adrenoreceptor. The significance of these results in relation to those published on the enantiomers of idazoxan and to those on optically active alpha 2-adrenoreceptor agonists is discussed. 相似文献
19.
A Messineo R M Filler B Bahoric C Smith A Bahoric 《Journal of pediatric surgery》1991,26(11):1296-1300
A major problem in tracheal transplantation is the restoration of an adequate vascular supply to the transplanted trachea. In 12 piglets, a segment (6 rings) of thoracic trachea was removed and the excised segment was then sutured back in place. In 9 animals (group A), a vascularized omental flap was wrapped around the autotransplanted trachea. In the other 3 pigs (group B), the omentum was not used. Eight of 9 group A pigs were killed, 1 or 2 months later, having had no signs of airway obstruction; the 9th pig was killed after 14 days because of airway obstruction. The 3 pigs in group B were killed after 11 to 13 days because of progressive respiratory obstruction. In the 8 asymptomatic pigs in group A, the omental flap was viable and tracheal growth was normal with no differences in diameter between normal and autotransplanted trachea. Histologically intact cartilage was lined with respiratory epithelium. In the one group A pig who was killed early, the omental flap was necrotic. In this pig and in the 3 group B animals, extensive tracheal necrosis and nonviable cartilage were observed. These findings indicate that in the pig, a 6-ring segment of trachea can be transplanted with vascularization provided by an omental flap. 相似文献
20.
Complete Freund's adjuvant (CFA) administered before sensitization dampened the normal and cyclophosphamide-enhanced response of high and moderate IgE responder phenotype mice (CAF1 and C57B1/6J, respectively). CFA-induced suppression of IgE biosynthesis was effective in reducing anaphylactic histamine release from approximately 2,900 ng histamine per milliliter to background levels (less than 100 ng/ml). CFA-induced ascites fluid was able to reduce the cyclophosphamide-enhanced IgE response of low-responder phenotype SJL mice from 1:320 to less than 1:5 as determined by passive cutaneous anaphylaxis. Muramyl dipeptide, a mycobacterial cell wall component capable of eliciting effects similar to those seen with CFA, was shown to induce suppression of IgE production if incorporated in incomplete Freund's adjuvant. Muramyl dipeptide administered in saline was ineffective, while incomplete Freund's adjuvant alone had some immunoregulatory properties. Ongoing IgE responses were less susceptible to regulation. CFA administered to sensitized C57B1/6J mice was ineffective in inducing IgE suppression when animals were challenged with antigen. 相似文献