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   168篇
  免费   9篇
  国内免费   2篇
儿科学   7篇
妇产科学   1篇
基础医学   13篇
口腔科学   6篇
临床医学   14篇
内科学   25篇
神经病学   29篇
特种医学   3篇
外国民族医学   3篇
外科学   14篇
综合类   3篇
预防医学   27篇
眼科学   3篇
药学   16篇
中国医学   1篇
肿瘤学   14篇
  2023年   2篇
  2022年   2篇
  2021年   5篇
  2020年   2篇
  2019年   3篇
  2018年   7篇
  2017年   8篇
  2016年   5篇
  2015年   4篇
  2014年   10篇
  2013年   10篇
  2012年   17篇
  2011年   25篇
  2010年   14篇
  2009年   4篇
  2008年   11篇
  2007年   5篇
  2006年   8篇
  2005年   3篇
  2004年   9篇
  2003年   6篇
  2002年   3篇
  1999年   2篇
  1998年   1篇
  1997年   2篇
  1991年   2篇
  1990年   1篇
  1988年   2篇
  1981年   1篇
  1979年   1篇
  1976年   1篇
  1973年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有179条查询结果,搜索用时 30 毫秒
1.
Birthweight is an important indicator of child survival. Appropriate and timely care of a newborn specially if he is born with low birthweight is important but this is difficult in developing countries since most of the deliveries are conducted at home where adequate facilities to weigh a new born does not exist. This study was conducted to find out a surrogate which could efficiently be used for detecting low birthweight babies at birth when no weighing machine is around. In this study 41% of the newborn babies were found to weigh less than 2,500 gm at birth. Out of this about 52% were females. The mean chest, thigh and mid-arm circumference at birth for males were 30.89 cm, 15.06 cm and 9.27 cm respectively with standard deviations of 1.83 cm, 1.30 cm and 1.04 cm. Corresponding figures for female babies were 30.69 cm, 15.14 cm and 9.25 cm respectively with standard deviations of 2.08 cm, 1.70 cm and 1.16 cm. Correlation co-efficient between normal birthweight and the chest, thigh and mid-arm circumference were 0.867, 0.845 and 0.842 respectively. A liner regression analysis showed that a chest circumference of 30.14 cm, a thigh circumference of 14.56 cm and a mid-arm circumference of 8.90 cm corresponded well with a birthweight of 2,500 gm. On this basis sensitivity, specificity and predictive values of the chest circumference was better than the other two measurements. However, the mid-arm circumference was observed to be more reliable than the other two measurements for detecting birthweight less than 2,000 gm. A home made measuring tape has been devised on this basis to detect brithweights with cut-off values for 2,500 gm, 2,000 gm to 2,500 gm and 2,000 gm in different shades of colour for illiterate birth attendants.  相似文献   
2.
Amino acids are important taste stimuli for a variety of animals. One animal model, the channel catfish, I. punctatus, possesses sensitive taste receptor systems for several amino acids. Neurophysiological and biochemical receptor binding studies suggest the presence of at least three receptor pathways: one is a relatively nonspecific site(s) responsive to short-chain neutral amino acids such as L-alanine (L-ALA); another is responsive to the basic amino acid L-arginine (L-ARG); still another is a low affinity site for L-proline (L-PRO). Several possible transduction pathways are available in the taste system of this animal model for these amino acids. One of these, formation of inositol trisphosphate (IP3) and cyclic AMP (cAMP), is mediated by GTP-binding regulatory proteins, while another involves ion channels directly activated by stimuli. L-ALA is a potent stimulus to cAMP and IP3 accumulation, while L-ARG at low concentrations is without effect. On the other hand, L-ARG and L-PRO, but not L-ALA, are able to activate stimulus-specific and cation-selective channels in taste epithelial membranes reconstituted in phospholipid bilayers at the tips of patch pipettes. Preliminary studies using mouse taste tissue demonstrate that monosodium-L-glutamate (MSG) did not enhance production of IP3 or cAMP. However, in reconstitution experiments using taste epithelium of mouse, conductance changes due to MSG are observed. The specificity of this channel(s) and its uniqueness have yet to be determined.  相似文献   
3.
ObjectivesDementia increases the risk of unsafe driving, but this is less apparent in preclinical stages such as mild cognitive impairment (MCI). There is, however, limited detailed data on the patterns of driving errors associated with MCI. Here, we examined whether drivers with MCI exhibited different on-road error profiles compared with cognitively normal (CN) older drivers.DesignObservational.Setting and ParticipantsA total of 296 licensed older drivers [mean age 75.5 (SD = 6.2) years, 120 (40.5%) women] recruited from the community.MethodParticipants completed a health and driving history survey, a neuropsychological test battery, and an on-road driving assessment including driver-instructed and self-navigation components. Driving assessors were blind to participant cognitive status. Participants were categorized as safe or unsafe based on a validated on-road safety scale, and as having MCI based on International Working Group diagnostic criteria. Proportion of errors incurred as a function of error type and traffic context were compared across safe and unsafe MCI and CN drivers.ResultsCompared with safe CN drivers (n = 225), safe MCI drivers (n = 45) showed a similar pattern of errors in different traffic contexts. Compared with safe CN drivers, unsafe CN drivers (n = 17) were more likely to make errors in observation, speed control, lane position, and approach, and at stop/give-way signs, lane changes, and curved driving. Unsafe MCI drivers (n = 9) had additional difficulties at intersections, roundabouts, parking, straight driving, and under self-navigation conditions. A higher proportion of unsafe MCI drivers had multidomain subtype [n = 6 (67%)] than safe MCI drivers [n = 11 (25%)], odds ratio 6.2 (95% confidence interval, 1.4–29.6).Conclusion and ImplicationsAmong safe drivers, MCI and CN drivers exhibit similar on-road error profiles, suggesting driver restrictions based on MCI status alone are unwarranted. However, formal evaluation is recommended in such cases, as there is evidence drivers with multiple domains of cognitive impairment may require additional interventions to support safe driving.  相似文献   
4.
Objective:The aim of our study was to measure and compare the serum hormone level of transplant group with blank control and castrated control groups after heterotopic autotransplantation of cryopreserved-thawed ovarian tissues into back muscles. Methods:A total of 40 SPF-SD female rats (5-6 week-old) were randomly divided into three groups:blank control group (group A), castration control group (group B) and transplant group (group C). Ovaries were removed by surgical procedure, then after cryopreservation and thawing procedures the ovarian tissues were implanted into the back muscles of mice in group C. After 4 weeks of ovarian tissues transplantation, al rats blood sampling were measured for E2, LH and FSH hormone levels by ELISA. Results:E2 level was significantly higher in group C and group A than group B [(38.98 ± 5.66) pg/mL, (8.14 ± 3.24) pg/mL;P<0.05) and [(36.30 ± 6.90) pg/mL, (8.14 ± 3.24) pg/mL;P<0.05)]. However, E2 level in group C and group A had no significant dif erence. FSH level in group B, group A and group C was (18.87 ± 2.54) nmol/L, (7.77 ± 0.87) nmol/L and (9.39 ± 2.12) nmol/L respectively. FSH level increased significantly in group B compared with group A, and the dif erence had statistical significance (P<0.05). FSH level was slightly increased in group C compared with group A, and the dif erence was not statistical y significant (P>0.05), but compared with group B, FSH level was significantly reduced and being statistical y significant (P<0.05). Conclusion:Autotransplantation of cryopreserved-thawed ovarian tissue into back muscles can sustain fol icular development and re-establish endogenous hormone production by restoring the factors such as angiogenesis and innervations at the graft site.  相似文献   
5.
Life expectancy (LE) among the Japanese population with or without diabetes mellitus was estimated. LE in 40-year old men and women was 41.1 and 47.5 years in those without diabetes and 32.3 and 40.9 years in those with diabetes. The LE of 40-year old men and women with diabetes was 8.8 and 6.6 years shorter than in those without diabetes. Diabetes mellitus leads to a decrease in LE. The presence of impaired glucose tolerance also affected LE inversely.  相似文献   
6.
PurposeCardiovascular (CV) diseases account for most worldwide mortality, and a higher level of lipoprotein (Lp)-(a) is recognized as a prevalent contributing risk factor. However, there is no consensus regarding nutritional strategies for lowering Lp(a) concentration. Thus, the purposes of this literature review were to: (1) critically examine data concerning the effects of dietetic interventions and nutraceutical agents on Lp(a) level; and (2) review the feasibility and utility of their clinical use.MethodsA literature search was conducted for studies published between August 2018 and March 2019. The search was performed using the Cochrane, Medline, and Web of Science databases. In order to expand the research, there were no delimitations on the type or year of the studies. A total of 1932 articles were identified using this search procedure. After duplicates were eliminated, 740 abstracts of articles written in English were screened to identify those of highest relevance. In the final tally, a total of 152 full-text articles were included in this review.FindingsSeveral foods and decreases in saturated fat and ethanol intake, especially red wine intake, may lower Lp(a) concentration, but limits are necessary. Coffee and tea intake may decrease Lp(a) level; further investigation is crucial before they can be considered potent Lp(a)-lowering agents. Among supplementation strategies, only l-carnitine and coenzyme Q10 are promising clinical candidates to lower Lp(a) level. Since both l-carnitine and coenzyme Q10 supplementation are commonly used for CV support, they deserve further exploration regarding clinical applicability. In contrast, despite potential CV benefits, current research fails to justify use of higher intakes of vitamin C, soy isoflavones, garlic, and ω-3 for decreasing Lp(a) concentration.ImplicationsDefinitive long-term clinical trials are needed to confirm the effects of dietetic interventions and nutraceutical agents on Lp(a) concentration when anticipating improved CV outcomes.  相似文献   
7.
During the last decade, many novel approaches for addressing multiplicity problems arising in clinical trials have been introduced in the literature. These approaches provide great flexibility in addressing given clinical trial objectives and yet maintain strong control of the familywise error rate. In this tutorial article, we review multiple testing strategies that are related to the following: (a) recycling local significance levels to test hierarchically ordered hypotheses; (b) adapting the significance level for testing a hypothesis to the findings of testing previous hypotheses within a given test sequence, also in view of certain consistency requirements; (c) grouping hypotheses into hierarchical families of hypotheses along with recycling the significance level between those families; and (d) graphical methods that permit repeated recycling of the significance level. These four different methodologies are related to each other, and we point out some connections as we describe and illustrate them. By contrasting the main features of these approaches, our objective is to help practicing statisticians to select an appropriate method for their applications. In this regard, we discuss how to apply some of these strategies to clinical trial settings and provide algorithms to calculate critical values and adjusted p‐values for their use in practice. The methods are illustrated with several numerical examples. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
8.
9.
The inhibitory action of five azoles namely benzotriazole (BTA), mercaptobenzothiazole (MBT), benzimidazole (BIMD), mercaptobenzimidazole (MBIMD) and thiadiazole (TDA) on copper was examined in sodium borate solution of pH 6.4, 8.4 and 10.4 using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A considerable drop off in the corrosion rate of copper was detected in the presence of the investigated compounds. CV showed that the inhibitors were of mixed type that they affect both the anodic and cathodic currents. Impedance spectra were characterized in terms of the charge transfer resistance and transport of copper ions through the oxide layer. The results indicate that the surface layer is of dielectric nature, and its protection increases with increasing inhibitor concentration and solution pH. On the basis of calculated adsorption data the process was concluded as chemisorption. Some quantum chemical parameters were also calculated using ab initio Hartree–Fock 6-31G*basis set and were used to complement the experimental results. The relative inhibition efficiencies of the azoles in controlling the copper corrosion was found to be in order of MBT > TDA > MBIMD≈BIMD > BTA.  相似文献   
10.
Completeness of cytoreduction is an independent prognostic factor after cure-intended surgery for peritoneal carcinomatosis. NV1066, a genetically engineered herpes simplex virus carrying the transgene for green fluorescent protein, selectively infects cancer cells. We sought to determine the feasibility of virally directed fluorescent imaging in the intraoperative detection of minimal residual disease after cytoreductive surgery. NV1066 infected human gastric cancer cells, OCUM-2MD3, and mesothelioma JMN cells at all doses. The infected cells expressed green fluorescent protein and were killed. OCUM-2MD3, and mesothelioma JMN cells at all doses. Peritoneal carcinomatosis was established in mice by injection of OCUM cells into the peritoneal cavity. Forty-eight hours after intraperitoneal injection of NV1066, two experienced surgeons resected all visible disease and identified mice free of disease. Eight of 13 mice thought to be free of disease were found to have residual disease as identified by green fluorescence (mean number of observations: 5; range: 1–9). Residual disease was most frequently observed in the retroperitoneum, pelvis, peritoneal surface, and liver. Specificity of NV1066 infection to tumor nodules was confirmed by immunohistochemistry and by polymerase chain reaction for viral gene. Virally directed fluorescent imaging, a novel molecular imaging technology, can be used for real-time visualization of minimal residual disease after cytoreductive surgery and can improve the completeness of cure-intended resection. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–18, 2005 (oral presentation) Supported in part by AstraZeneca Cancer Research and Prevention fellowship (P.S.A), training grant T 32 CA09501 (D.P.E and K.J.H.), grants RO1 CA 76416 and RO1 CA/DK80982 (Y.F.) from the National Institutes of Health, grant BC024118 from the U.S. Army (Y.F.), grant IMG0402501 from the Susan G. Komen Foundation (Y.F. and P.S.A), and grant 032047 from the Flight Attendant Medical Research Institute (Y.F. and P.S.A).  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