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   733篇
  免费   43篇
  776篇
  2022年   2篇
  2021年   2篇
  2020年   4篇
  2019年   5篇
  2018年   7篇
  2017年   7篇
  2016年   11篇
  2015年   20篇
  2014年   30篇
  2013年   36篇
  2012年   51篇
  2011年   41篇
  2010年   27篇
  2009年   21篇
  2008年   45篇
  2007年   43篇
  2006年   46篇
  2005年   34篇
  2004年   41篇
  2003年   42篇
  2002年   44篇
  2001年   10篇
  2000年   15篇
  1999年   9篇
  1998年   7篇
  1997年   16篇
  1996年   8篇
  1995年   8篇
  1994年   11篇
  1993年   7篇
  1992年   17篇
  1991年   13篇
  1990年   8篇
  1989年   8篇
  1988年   10篇
  1987年   8篇
  1986年   12篇
  1985年   3篇
  1984年   4篇
  1983年   3篇
  1982年   4篇
  1980年   3篇
  1979年   2篇
  1978年   4篇
  1977年   4篇
  1975年   2篇
  1974年   3篇
  1964年   5篇
  1962年   2篇
  1961年   2篇
排序方式: 共有776条查询结果,搜索用时 15 毫秒
51.
Seven-week old female rats fed restricted foods including the fish oils Docosahesaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA) and perilla oil with food intake decreased by 50%, had increases of fracture force and bone mineral density (BMD) and decreases in levels of Deoxypiridinoline (Dpd) and Calcium (Ca) in the urine, compared with those of rats with osteoporosis due to restricted soy bean oil food intake. Therefore, the fish oils DHA and EPA and perilla oil depressed excretion of urinary Ca and inhibited osteoporosis due to restricted food intake.  相似文献   
52.
Running at 0.7 km/h for 10 min every day inhibited development of osteoporosis caused by protein deficient (PD) food intake. Urine alkaline phosphatase (ALP), a marker of bone formation osteoporosis, was not elevated in rats fed PD, when the osteoporosis was inhibited by running. Estrogen supplementation increased bone-breaking energy (BBE), but did not increase bone mineral density (BMD), and did not decrease urinary ALP levels.  相似文献   
53.
54.
A new rockfish, Sebastes kiyomatsui, is described on the basis of 13 specimens from the Pacific coast of southern Japan. The new species resembles S. scythropus in having two sharp preorbital and robust preocular, supraocular, and postocular spines, but differs from the latter in having a black blotch on the opercle not extending to the subopercle, indistinct crimson marks on the body, blackish region of the oral cavity reaching to the prevomer and palatine, blackish tongue, a small ridge on the upper edge of the lachrymal, somewhat larger orbit, somewhat lower caudal peduncle, and seven lower unbranched pectoral fin rays. Sebastes kiyomatsui is a deep water (ca. 250m) inhabitant.  相似文献   
55.
The phylogenetic relationships of all 16 genera (plus Psenes pellucidus) of the suborder Stromateoidei were estimated cladistically based on 43 osteological, myological, and external characters. Thirty equally parsimonious trees were obtained. Based on the strict consensus tree, Centrolophidae was nonmonophyletic, Psenopsis being placed as a sister group of a clade comprising Amarsipus, Ariomma, nomeids, Tetragonurus, and stromateids. Schedophilus formed a sister group relationship with Seriolella. The relationships among the Centrolophus, Hyperoglyphe, Icichthys, Tubbia, Schedophilus+Seriolella clade, and Psenopsis+Amarsipus+Ariomma+nomeids+Tetragonurus+stromateids clade were unresolved. Amarsipus, which is unique within the suborder in lacking a pharyngeal sac, was nested within the stromateoid clade, being a sister group of the clade including Ariomma, nomeids, Tetragonurus, and stromateids. The absence of a pharyngeal sac in Amarsipus was interpreted as a reversal, its presence in the Stromateoidei therefore being considered as a synapomorphy. Ariomma was placed as the sister group of a clade comprising nomeids, Tetragonurus, and stromateids. Monophyly of the Nomeidae and Stromateidae were supported by 2 and 11 synapomorphies, respectively.  相似文献   
56.
A series of novel 6-methylene-bridged uracil derivatives have been optimized for clinical use as the inhibitors of human thymidine phosphorylase (TP). We describe their synthesis and evaluation. Introduction of a guanidino or an amidino group enhanced the in vitro inhibitory activity of TP comparing with formerly reported inhibitor 1. Their selectivity for TP based on uridine phosphorylase inhibitory activity was also evaluated. Compound 2 (TPI) has been selected for clinical evaluation based on its strong TP inhibition and excellent modulation of 2'-deoxy-5-(trifluoromethyl)uridine (F(3)dThd) pharmacokinetics. As a result, TAS-102 (a combination of F(3)dThd and TPI) is currently in phase 1 clinical studies.  相似文献   
57.
The time course of acute changes in large artery distensibility immediately and for 60 min following maximum treadmill exercise in normal subjects was characterized by simultaneously measuring upper and lower limb pulse wave velocity (PWV). A new oscillometric technique was used, which has proven to be sensitive to changes in distensibility induced by acute changes in vascular tone independently of blood pressure. The observed changes in PWV are attributable to changes in vascular tone corresponding to recovery from a systemic net constrictor response and a local net dilator response to exercise with persisting postexercise vasodilatation. They are inadequately explained by associated changes in blood pressure and cannot be attributed to changes in heart rate or viscosity. Modeled as a system of n coupled linear differential equations, the minimum (and adequate) order required to reproduce these patterns was n = 1 for the upper and n = 2 for the exercising lower limb. The economy of the solution suggests entrainment among the multiple interactive mechanisms governing vasomotor control.  相似文献   
58.
59.
A series of 1-phenylpyrazoles was evaluated for inhibitory activity against xanthine oxidase in vitro. Of the compounds prepared, 1-(3-cyano-4-neopentyloxyphenyl)pyrazole-4-carboxylic acid (Y-700) had the most potent enzyme inhibition and displayed longer-lasting hypouricemic action than did allopurinol in a rat model of hyperuricemia induced by the uricase inhibitor potassium oxonate.  相似文献   
60.
Aims: To validate an assessment of qualities of complete dentures that may relate to functional success. Subjects: A consecutive sample of 131 complete denture wearers took part in the study. Setting: a Greek department of prosthetic dentistry. Intervention : All participants and their dentures underwent clinical examination. Design: The Functional Assessment of Dentures (FAD) 10‐item criteria1 describing clinical factors of denture quality was used. The rationale for selecting these particular criteria was to include a range of clinical factors to produce an overall assessment of complete dentures. The 10‐item scale was examined for Internal Consistency and Construct Validity providing a summated rating scale whose total score could be used as an index for the quality of dentures. Results: Both intra‐ and inter‐examiner agreement for all 10 dichotomous scale criteria were all good or very good; the intra‐examiner Kappa values were 0.72 to 0.91 and the inter‐ examiner values were 0.72 to 0.99. Statistical analysis revealed that a 7‐item summated rating scale could be constructed which has marginally better internal consistency (reliability) and Construct Validity with fewer questions. Conclusions: The FAD criteria1 can be used to give good repeatability. The adjustments made to the original summation scale, if confirmed by new studies, would further increase the practical utility of a FAD index for general dentists. In due course with data from future studies, discrimination on weighting of items will be appropriate to relate the impact of denture quality on quality of life.  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