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   9964篇
  免费   880篇
  国内免费   21篇
耳鼻咽喉   74篇
儿科学   341篇
妇产科学   289篇
基础医学   1348篇
口腔科学   162篇
临床医学   1342篇
内科学   1847篇
皮肤病学   189篇
神经病学   956篇
特种医学   253篇
外科学   980篇
综合类   120篇
一般理论   16篇
预防医学   1292篇
眼科学   162篇
药学   732篇
中国医学   13篇
肿瘤学   749篇
  2023年   120篇
  2022年   138篇
  2021年   242篇
  2020年   220篇
  2019年   271篇
  2018年   288篇
  2017年   236篇
  2016年   282篇
  2015年   290篇
  2014年   347篇
  2013年   532篇
  2012年   758篇
  2011年   799篇
  2010年   397篇
  2009年   332篇
  2008年   637篇
  2007年   616篇
  2006年   604篇
  2005年   560篇
  2004年   434篇
  2003年   467篇
  2002年   410篇
  2001年   114篇
  2000年   111篇
  1999年   115篇
  1998年   87篇
  1997年   58篇
  1996年   66篇
  1995年   48篇
  1994年   60篇
  1993年   46篇
  1992年   72篇
  1991年   59篇
  1990年   75篇
  1989年   67篇
  1988年   63篇
  1987年   56篇
  1986年   56篇
  1985年   34篇
  1984年   36篇
  1983年   52篇
  1982年   36篇
  1981年   32篇
  1979年   39篇
  1978年   33篇
  1977年   31篇
  1975年   30篇
  1974年   34篇
  1973年   45篇
  1972年   31篇
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
91.
Résumé L'étude porte sur une série de 50 prothèses totales de genou GSB implantées entre 1981 et 1988 au Centre de Traumatologie et d'Orthopédie de Strasbourg. Cette prothèse entre dans la catégorie des prothèses à charnières cimentées, mais son pivot semi rigide diminue efficacement les contraintes exercées sur le ciment. Les résultats sont conformes à ceux retrouvés dans la littérature concernant les prothèses à charnière. L'accent a été mis plus particulièrement sur les complications spécifiques à ce type d'arthroplastie : infections, fractures, complications rotuliennes. Cependant le caractère semi rigide de la GSB a permis la disparition presque totale des descellements qui compliquaient d'ordinaire les prothèses à charnière. La prothèse GSB nous semble donc supérieure aux autres modèles de prothèse à charnière.  相似文献   
92.
To strengthen their operations many hospitals have embraced total quality management (TQM) strategies used by companies throughout the world. California Hospitals examines how some of these hospitals have used TQM to improve clinical outcomes, cut costs, boost staff morale and increase patient satisfaction.  相似文献   
93.
The immobilization of vesicles has been conceptualized as a method to functionalize biointerfaces. However, the preservation of their integrity post immobilization remains a considerable challenge. Interfacial interactions can cause vesicle rupture upon close surface contact and non-specific protein adsorption impairing surface functions. To date, immobilization of vesicles has relied solely on either entrapment or prior modification of vesicles, both of which require laborious preparation and limit their applications. This work develops a bioinspired strategy to pin vesicles without prior modification while preserving their intact shape. This work introduces antifouling diblock copolymers and ultrathin surface-attached hydrogels containing a brush-like interface consisting of a bottle brush copolymer of N-(2-hydroxypropyl) methacrylamide (HPMA) and N-(3-methacrylamidopropyl)-N,N-dimethyldodecan-1-aminiumiodide (C12+). The presence of positive charges generates an attractive force that pulls vesicles toward the surface. At the surface, the amphiphilic properties of the combs facilitate their insertion into the membrane, mimicking the harpooning mechanism observed in antimicrobial peptides. Importantly, the antifouling poly(HPMA) backdrop serves to safeguard the vesicles by preventing deformation and breakage. Using a combination of thermodynamic analysis, surface plasmon resonance, and confocal laser scanning microscopy, this work demonstrates the efficiency of this biomimetic system to capture vesicles while maintaining an antifouling interface necessary for bioapplications.  相似文献   
94.
Adverse event monitoring is a problem-oriented approach to clinical audit and health-care quality improvement, which was developed and has been widely used in the USA. Briefly explores the technique itself and its evolution. Presents experience gained from the widespread use of the approach in a British acute hospital, and results from one specialty--ophthalmology. Suggests that the study of adverse events in patient care can produce significant improvements in patients' care, that it is particularly suited to some specialties, and that it should be used alongside other techniques in hospital clinical audit programmes. Concludes that, as the demand for quality-monitoring information from purchasers and within providers grows, adverse event monitoring may become one of the key techniques for quality assessment and improvement.  相似文献   
95.
Caloric restriction (CR), undernutrition without malnutrition, remains the only experimental paradigm that has been shown consistently to extend lifespan and slow aging in short-lived species. Decades of research, mostly in laboratory rodents, have shown that CR consistently extends lifespan, reduces or delays the onset of many age-related diseases and slows aging in many physiological systems. In recent years gerontologists interested in CR have focused on two unanswered questions. 1) What is the relevance of this nutritional paradigm to human aging? and 2) What biological mechanism(s) underlie the diverse effects of CR leading to a retardation of aging and disease?. To address the question of human relevance, researchers in the Intramural Research Program of the National Institute on Aging began a study of CR in nonhuman primates in the late 1980s. In addition to assessing the effects of CR on aging in primates, a major focus of this work relates to possible metabolic mechanisms of CR. A subsequent study at the University of Wisconsin Madison was initiated in the early 1990s. Certain aspects of experimental design differ between these two important ongoing investigations, but generally these studies compliment each other in many ways and have begun to provide much important data regarding the effects of CR in primates. Emerging data from these studies strongly support that physiological responses to CR in monkeys parallel the extensive findings reported in rodents. Lifespan data will not be available for several years, however, the remarkable consistency with rodent studies, in which lifespan extension is documented extensively, strengthens the possibility that CR will also extend lifespan in primates, perhaps including humans. This review summarizes the major findings from the primate CR studies after over a decade of research in this model.  相似文献   
96.
We studied the holding power during cut-out tests of 4 different screw fixation devices of the femoral head, correlated to head size and bone density, on 48 paired deep frozen proximal femurs of fresh gross specimens. We found no significant effect of the device on the holding power. There was a significantly higher maximal load at failure in large and dense heads. It seems then unnecessary to advocate more sophisticated but also more expensive devices to fix femoral neck fractures.  相似文献   
97.
98.
This review focuses on malformations of the central nervous system that have a genetic etiology. One can view each malformation as giving us unique details on a map entitled "how to make a human brain." The gene(s) that cause each malformation are being identified, allowing discovery of their specific role in neurodevelopment, and defining a "road" on the map. The malformation is then the developmental consequence of "taking a wrong turn." Assimilation of complementary data from other species with human malformation phenotype and genotype is revealing just how wonderful and complex the neurodevelopment map is. Here we highlight recent research on brain malformations and how this is illuminating the map of normal human brain formation.  相似文献   
99.
The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly susceptible to upper respiratory disease and showed the greatest rate of seroconversion to influenza viruses. Major outbreaks of respiratory disease occurred when the proportion of young horses which had not previously been exposed to epidemics of respiratory disease reached 30 to 40% of the population at the track. Most horses over four years of age appeared to develop resistance to the infections.  相似文献   
100.
Refraction as a basis for screening children for squint and amblyopia.   总被引:10,自引:10,他引:0       下载免费PDF全文
+2-00 to +2-75 dioptres of spherical hypermetropia in the more emmetropic of a pair of eyes is significantly associated with esotropia (P less than 0-001) and the presence of amblyopia (P less than 0-01). Anisometropia is not significantly associated with esotropia (P = 0-31) unless there is spherical hypermetropia of +2-00 dioptres or more in the more emmetropic eye (P less than 0-001). Hypermetropic anisometropia of +1-00 DS or +1-00 D.Cyl. is associated with the presence of amblyopia (P less than 0-001). In the absence of esotropia there is also a significant association between the amount of anisometropia and the initial depth of amblyopia (P less than 0-01). The additional presence of esotropia increases the depth of amblyopia further (P less than 0-05) but not the incidence of amblyopia (P greater than 0-30). The level of significance of the association of refractive errors with squint/amblyopia was itself significantly higher (P less than 0-01) than that between a family history of squint or "lazy eye" on the one hand and squint and/or amblyopia on the other hand. 72 +/- 3% of all cases of esotropia and/or amblyopia in this sample of children had a refractive error of +2-00 DS or more spherical hypermetropia in the more emmetropic eye, or +1-00 D. or more spherical or cylindrical anisometropia. Since there is a close association between the refraction and how, when, and whether a child presents with squint and/or amblyopia, it would seem reasonable to reconsider refraction as a basis for screening young children for visual defects.  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