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   28518篇
  免费   1893篇
  国内免费   323篇
耳鼻咽喉   508篇
儿科学   437篇
妇产科学   515篇
基础医学   4120篇
口腔科学   601篇
临床医学   2418篇
内科学   6049篇
皮肤病学   839篇
神经病学   1926篇
特种医学   1587篇
外科学   3732篇
综合类   810篇
现状与发展   1篇
一般理论   16篇
预防医学   1319篇
眼科学   1034篇
药学   2251篇
中国医学   258篇
肿瘤学   2313篇
  2023年   258篇
  2022年   628篇
  2021年   1075篇
  2020年   581篇
  2019年   764篇
  2018年   990篇
  2017年   708篇
  2016年   1004篇
  2015年   1255篇
  2014年   1464篇
  2013年   1631篇
  2012年   2470篇
  2011年   2392篇
  2010年   1360篇
  2009年   1195篇
  2008年   1619篇
  2007年   1601篇
  2006年   1451篇
  2005年   1386篇
  2004年   1106篇
  2003年   901篇
  2002年   740篇
  2001年   609篇
  2000年   582篇
  1999年   458篇
  1998年   162篇
  1997年   122篇
  1996年   85篇
  1995年   100篇
  1994年   90篇
  1993年   74篇
  1992年   167篇
  1991年   176篇
  1990年   146篇
  1989年   144篇
  1988年   120篇
  1987年   143篇
  1986年   111篇
  1985年   97篇
  1984年   75篇
  1983年   71篇
  1982年   37篇
  1979年   66篇
  1977年   42篇
  1975年   42篇
  1974年   39篇
  1973年   37篇
  1972年   37篇
  1970年   35篇
  1969年   40篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
BACKGROUND: Higher house dust mite (HDM) allergen exposure during infancy has been associated with increased HDM sensitization. Infant bedding has been associated with the accumulation of varying levels of HDM. Prospective data on the relationship between infant bedding and the development of HDM sensitization has not been previously examined. OBJECTIVES: To determine if particular types of bedding used in infancy are associated with increased risk of house dust mite sensitization in childhood. METHODS: A population-based sample (n = 498) of children born in 1988 or 1989, and who were resident in Northern Tasmania in 1997, participated in this study. These children were part of a birth cohort study (1988-95), the Tasmanian Infant Health Survey. Data on infant underbedding and mattresses was available on 460 and 457 children, respectively. The main outcome measure was HDM sensitization defined as a skin prick test (SPT) reaction of 3 mm or more to the allergens of Dermatophagoides pteronyssinus and/or Dermatophagoides farinae. RESULTS: The use of either sheepskin underbedding or plastic mattress covers in infancy was associated with an increased risk of sensitization to HDM allergens at age 8 years. The adjusted risk ratio (RR) for sensitization to HDM with sheepskin in infancy was 2.27 (95% CI: 1.14, 4.55), P = 0.020. The adjusted RR for sensitization to HDM with the use of plastic mattress covers in infancy was 2.06 (95% CI: 1.22, 3.51), P = 0.007. The use of a foam mattress in infancy was not related to subsequent HDM sensitization. CONCLUSION: Infant's bedding plays a role in the development of HDM sensitization in childhood. Intervention studies to examine mite allergen levels and the role of underbedding on the development of HDM sensitization are required.  相似文献   
23.
Objectives. To evaluate the process of soft-tissue electrovaporization and to study variables that affect tissue clearance rates in a laboratory setting, in order to identify parameters that can optimize transurethral electrovaporization of the prostate.Methods. Fresh bovine skeletal muscle, equivalent in impedance and surface properties to the human prostate, was submerged in 3.3% sorbitol solution and electrovaporized with a grooved monopolar electrode attached to the weighted arm of a linear actuator. The effects of excursion rate, applied mechanical load, power setting, electrode configuration, and generator performance on the volume of tissue removed, were assessed.Results. Tissue removal increased significantly when electrode excursion rate was slowed from 25 to 15 mm/s (P <0.05) and then to 10 mm/s (P <0.05); when the load was increased from 20 to 50 g (P <0.005); and when dial power was increased from 120 to 150 W (P <0.01). Tissue removal was generator dependent. There was no significant difference between the Force 40 and the Force 2 (P > 0.4), but a new computer-controlled constant power output generator (Force FX) did significantly improve tissue vaporization at an equivalent power setting (P <0.005 and P <0.01, respectively). Tissue removal was also dependent upon electrode configuration, with the VaporTrode-Grooved Bar removing significantly more tissue than either an ungrooved roller bar of equivalent size or 2-mm smooth roller ball, respectively, both after a single pass (P <0.001 and P <0.05) and after five repeated passes (P <0.05 and P <0.005). The histologic depth of tissue thermal effect was less than 1 mm, but it was 38% greater for the VaporTrode-Grooved Bar (0.68 mm) than for the standard cutting loop (0.5 mm, P <0.01).Conclusions. Using a novel method to quantify tissue removal, we have demonstrated that electrode configuration, excursion rate, applied load, power setting, and generator performance are interdependent factors that influence the efficacy of the electrovaporization process in a fluid environment.  相似文献   
24.
Consumers were surveyed to determine their attitudes toward four systems of health care delivery (home health care, hospitals, nursing homes, and outpatient clinics) along 10 attributes. The results are analyzed using multiple discriminant analysis. Implications for the formulation of marketing strategies are discussed.  相似文献   
25.
26.
27.
S. L. Lim  MB  BS  MMed    D. H. B. Tay  MB  BS  MMed  FAMS    E. Thomas  MB  BS  MMed  FANZCA  FAMS   《Anaesthesia》1994,49(3):255-257
  相似文献   
28.
We describe a case of preeclampsia with the HELLP (Haemolysis, Elevated Liver enzymes, Low Platelets) syndrome and highlight the delayed diagnosis due to its nonspecific presentation. This syndrome is associated with significant maternal and perinatal mortality and morbidity and we discuss the importance of early recognition of the condition, aggressive management and a multidisciplinary approach.  相似文献   
29.
30.
4 cases of syringomyelia with type I Arnold Chiari malformation was seen presenting mainly with dissociated sensory loss, weakness of hands and upper motor neurone signs in the lower limbs. The first patient improved with posterior fossa decompression. The second and fourth patient appeared not to have improved after surgery, and the third case refused operation. One patient showed cord atrophy on myelogram presumably due to a collapse of the syrinx. One of the patients was unusual in that the syrinx extended down to segment T11. Magnetic resonance imaging of the posterior fossa and the cervical cord, to date, is the most useful procedure for diagnosis.  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