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   3637篇
  免费   471篇
  国内免费   44篇
耳鼻咽喉   26篇
儿科学   124篇
妇产科学   102篇
基础医学   571篇
口腔科学   89篇
临床医学   394篇
内科学   799篇
皮肤病学   188篇
神经病学   176篇
特种医学   221篇
外科学   417篇
综合类   79篇
一般理论   1篇
预防医学   366篇
眼科学   61篇
药学   308篇
中国医学   13篇
肿瘤学   217篇
  2021年   60篇
  2020年   33篇
  2019年   44篇
  2018年   70篇
  2017年   67篇
  2016年   47篇
  2015年   79篇
  2014年   72篇
  2013年   100篇
  2012年   125篇
  2011年   133篇
  2010年   108篇
  2009年   94篇
  2008年   135篇
  2007年   150篇
  2006年   149篇
  2005年   141篇
  2004年   147篇
  2003年   127篇
  2002年   118篇
  2001年   97篇
  2000年   121篇
  1999年   124篇
  1998年   90篇
  1997年   72篇
  1996年   77篇
  1995年   60篇
  1994年   64篇
  1993年   58篇
  1992年   109篇
  1991年   88篇
  1990年   90篇
  1989年   105篇
  1988年   94篇
  1987年   93篇
  1986年   65篇
  1985年   68篇
  1984年   77篇
  1983年   57篇
  1982年   44篇
  1981年   39篇
  1980年   37篇
  1979年   53篇
  1978年   39篇
  1977年   33篇
  1976年   34篇
  1973年   31篇
  1972年   29篇
  1971年   21篇
  1970年   20篇
排序方式: 共有4152条查询结果,搜索用时 15 毫秒
71.
72.
I D Hay  C S Grant  W F Taylor  W M McConahey 《Surgery》1987,102(6):1088-1095
From a multivariate analysis of more than 14,200 patient-years' experience with papillary thyroid carcinoma (PTC), we devised a prognostic scoring system based on patient age, tumor grade, extent, and size (AGES). This scoring system can identify patients at increased risk of PTC mortality and was employed as an adjustment variable for analyzing the role of different types of surgical treatment in 860 PTC patients. Cancer mortality at 25 years in patients with an AGES score of 3.99 or less was 1% after ipsilateral lobectomy (n = 131) and 2% after bilateral resection (n = 603), whether subtotal or total (p = 0.15). Of patients with an AGES score of 4 or more, those who underwent lobectomy alone (n = 30) had a mortality rate from PTC at 25 years of 65%, while those undergoing bilateral resection (n = 86) had a lower rate of 35% (p = 0.06). For patients at minimal risk (score of 3.99 or less) of PTC death, no improvement in survival was demonstrable when patients underwent more than ipsilateral lobectomy. However, in a subgroup (score of 4 or more) identified to be at significant risk of PTC death, the survival after bilateral resection was much higher than after ipsilateral lobectomy alone. In neither the "minimal" nor the "higher" risk subgroup was PTC survival significantly improved by the performance of total thyroidectomy.  相似文献   
73.
Between about ages 40 and 55 years, women experience a transition known as the menopause, which marks the end of their childbearing years. Although the most striking feature of the menopause is the cessation of menstruation, other biologic and psychosocial events occur and can be classified as stressors and "facilitators". For a predisposed group of women the stressors are likely to cause psychiatric disorders. At the same time, the facilitators are opportunities for personal growth and development. Physicians who understand both types of events during this phase of life and who are sensitive to the overall effects of ageing on marital partners can provide comprehensive care to the menopausal patient rather than automatically pursuing drug therapy (substitution hormonal therapy) alone.  相似文献   
74.
75.
Journal of Prevention - Understanding the behaviors that lead to sunburn is an important objective toward developing intervention strategies to reduce risk for skin cancers. Our cross-sectional...  相似文献   
76.
Orthorexia nervosa is a new syndrome that has seen a marked increase in research in the past decade. Very high prevalence estimates in non-clinical populations have fuelled the debate as to whether it is a disorder in its own right, or only a problem when occurring in the context of another mental health or eating disorder. More recent assessment instruments have gone some way to address this issue. However, He et al.'s (2020, International Journal of Eating Disorder) study in older East Asian persons was not supportive of orthorexia nervosa as a disorder. Rather, people with orthorexia nervosa had better physical and mental health and lower or similar levels of eating disorder features such as body dissatisfaction when compared with people who did not have orthorexia nervosa. Albeit that selection bias in participant recruitment may in part explain their findings, the status of orthorexia nervosa is unresolved. Further studies need to employ appropriate instruments that measure psychopathology and function more broadly and investigate people with orthorexia nervosa symptoms in representative populations with longitudinal designs. The last is critical, as the most compelling evidence supporting a disorder is to find an adverse health impact over time that can be avoided by appropriate intervention.  相似文献   
77.
Facial neglect     
Following a stroke, a retired industrial chemist, K.L., complained that faces looked "different" and had become difficult to recognize. Investigation of this problem revealed that it particularly affected the left half of a face as seen by K.L. Defective recognition of this (left) half was found for normal faces, chimaeric faces, and for half-faces presented in isolation, whether upright or inverted. The problem was apparent for both internal and external facial features. Further studies with chimaeric faces demonstrated inattention to left-side features in K.L.'s judgements of facial expression and of resemblance between faces. Moreover, the left-half of a chimaeric face was affected even when it was itself forming part of the face positioned on the right in a display of two horizontally aligned chimaerics. K.L.'s spatial contrast sensitivity function was within normal limits for his age. He did not experience differential difficulty in recognizing the left side of everyday objects or of car-fronts (another stimulus class demanding within-category discrimination between visually similar items that display approximate left-right symmetry). He was also able to sort left or right half-stimuli correctly into the categories "human face", "dog face", or "tree". Although K.L. had a left visual field defect, the problem with faces occurred within otherwise intact parts of his field of vision. We suggest that his disorder can be considered a domain-specific form of unilateral neglect.  相似文献   
78.
AIMS--To assess the performance of the polymerase chain reaction (PCR) when used to screen rapidly large numbers of corynebacteria for toxin production; and to determine the incidence of false positive PCR results with non-toxigenic Corynebacterium diphtheriae isolates. METHODS--Eighty seven recent British isolates of corynebacteria were assayed by PCR. All isolates were assayed from both blood and tellurite agar within a five day period. Thirty three non-toxigenic isolates of C diphtheriae from six countries were also tested by PCR and by the Elek immunodiffusion assay. RESULTS--There was complete concordance between the results of PCR and traditional methods on the recent British isolates, with one exception: an Elek positive "C ulcerans" isolate, which was PCR positive from tellurite but not from blood agar. One of the thirty three (3%) non-toxigenic isolates of C diphtheriae was PCR positive. CONCLUSIONS--These results suggest that PCR compares favourably with traditional methods for the detection of toxigenic corynebacteria and that it represents a powerful new tool in the diagnosis of an old disease.  相似文献   
79.
80.
Maternal protein deficiency causes fetal growth retardation which has been associated with the programming of adult disease. The growth of the rat fetus was examined when the mothers were fed on diets containing 180, 90 and 60 g protein/kg. The numbers of fetuses were similar in animals fed on the 180 and 90 g protein/kg diets but the number was significantly reduced in the animals fed on the 60 g protein/kg diet. The fetuses carried by the mothers fed on the 90 g protein/kg diet were 7.5% heavier than those of mothers fed on 180 g protein/kg diet on day 19 of gestation, but by day 21 the situation was reversed and the fetuses in the protein-deficient mothers were 14% smaller. Analysis of the free amino acids in the maternal serum showed that on day 19 the diets containing 90 and 60 g protein/kg led to threonine concentrations that were reduced to 46 and 20% of those found in animals fed on the control (180 g/kg) diet. The other essential amino acids were unchanged, except for a small decrease in the branched-chain amino acids in animals fed on the 60 g protein/kg diet. Both low-protein diets significantly increased the concentrations of glutamic acid+glutamine and glycine in the maternal serum. On day 21 the maternal serum threonine levels were still reduced by about one third in the group fed on the 90 g protein/kg diet. Dietary protein content had no effect on serum threonine concentrations in nonpregnant animals. Analysis of the total free amino acids in the fetuses on day 19 showed that feeding the mother on a low-protein diet did not change amino acid concentrations apart from a decrease in threonine concentrations to 45 and 26% of the control values at 90 and 60 g protein/ kg respectively. The results suggest that threonine is of particular importance to the protein-deficient mother and her fetuses. Possible mechanisms for the decrease in free threonine in both mother and fetuses and the consequences of the change in amino acid metabolism are discussed.  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