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   23729篇
  免费   2067篇
  国内免费   392篇
耳鼻咽喉   105篇
儿科学   823篇
妇产科学   271篇
基础医学   1584篇
口腔科学   999篇
临床医学   3144篇
内科学   4156篇
皮肤病学   182篇
神经病学   1756篇
特种医学   381篇
外国民族医学   1篇
外科学   2145篇
综合类   2654篇
现状与发展   1篇
预防医学   5072篇
眼科学   144篇
药学   1164篇
  32篇
中国医学   452篇
肿瘤学   1122篇
  2024年   57篇
  2023年   491篇
  2022年   948篇
  2021年   1791篇
  2020年   1231篇
  2019年   1020篇
  2018年   977篇
  2017年   955篇
  2016年   874篇
  2015年   906篇
  2014年   1533篇
  2013年   1834篇
  2012年   1309篇
  2011年   1427篇
  2010年   1132篇
  2009年   1200篇
  2008年   1203篇
  2007年   1145篇
  2006年   868篇
  2005年   724篇
  2004年   619篇
  2003年   536篇
  2002年   467篇
  2001年   368篇
  2000年   316篇
  1999年   257篇
  1998年   243篇
  1997年   218篇
  1996年   161篇
  1995年   176篇
  1994年   136篇
  1993年   117篇
  1992年   126篇
  1991年   105篇
  1990年   84篇
  1989年   86篇
  1988年   67篇
  1987年   55篇
  1986年   43篇
  1985年   79篇
  1984年   57篇
  1983年   39篇
  1982年   47篇
  1981年   31篇
  1980年   31篇
  1979年   30篇
  1978年   17篇
  1977年   12篇
  1976年   14篇
  1972年   8篇
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
101.
We assessed the feasibility and psychometric properties of two commonly used health status questionnaires in Parkinson's disease (PD): the generic Nottingham Health Profile (NHP) and the disease-specific 39-item Parkinson's disease Questionnaire (PDQ-39), from a cross-sectional postal survey of PD patients (N = 81), using traditional and Rasch measurement methodologies. Overall response rate was 88%. Both questionnaires were found feasible, although the NHP performed less well. The PDQ-39 had fewer floor effects and was better able to separate respondents into distinct groups than the NHP, whereas the latter exhibited less ambiguous dimensionality and better targeting of respondents with non-extreme scores. Reliability and validity indices were similar, and potential differential item functioning by age and gender groups was found for both questionnaires. PDQ-39 response alternatives indicated ambiguity. With few exceptions, questionnaire scales were unable to meet recommended standards fully. While preliminary, this study illustrates the need for thorough evaluation of outcome measures and has implications beyond the questionnaires used here. Although promising, both questionnaires warrant further developmental work and stronger support of measurement validity before they could be considered fully suitable for valid use in PD, in particular in earlier stages of the disease.  相似文献   
102.
Background: A survival disadvantage for black women with brest cancer, which persists after controlling for stage of the disease, has been reported. This study investigates the effects of race and socioeconomic status (SES) on breast cancer survival after controlling for age, stage, histology, and type of treatment. Methods: Kaplan-Meier and Cox proportional hazards models were used to analyze the interaction between race and SES in predicting survival in a sample of 163 black, 205 Hispanic, and 964 white women with breast cancer treated at M. D. Anderson Cancer Center (1987–1991). Results: The results of univariate and multivariate analyses indicate that race was not a significant predictor of survival after adjusting for SES and other confounding factors such as demographic and disease characteristics. SES remained a significant predictor of survival after all adjustments were made. There was no evidence of differences in type of treatment by race or SES if adjustments were made for stage. Conclusions: These results suggest that institutional factors, such as access to treatment, do not explain survival differences by race or SES. Other factors associated with low SES, such as life-style and behavior, may affect survival.  相似文献   
103.
As patterns of family formation change, it is important to know how children's lives are affected by their parents' marital and socioeconomic circumstances. Using data from the 1993 Kenya Demographic and Health Survey, this study shows that children of never married and formerly married mothers have significantly higher probabilities of polio dropout and acute undernutrition than those of monogamously married mothers. The number of male household members of working age greatly enhances the chances of full immunization and the nutritional status of children whose mothers were previously married. For children of never married mothers, the benefits of residing with males of working age are largely a function of ethnicity. The results also show that, although children are not disadvantaged nutritionally when their fathers have more than one wife, polygyny is associated with a higher probability of polio dropout and lower probability of full immunization than monogamy. Higher socioeconomic status is associated with a greater probability of full immunization and a lower probability of malnutrition but socioeconomic factors do not explain the effects of mothers' marital status. The findings underscore the complex realities of family interaction and the importance of the broader social context in accounting for variations in child welfare across diverse marital situations.  相似文献   
104.
OBJECTIVE: This study proposes a method for self-report health questionnaires to adjust test-retest reliability for changes during the test-retest interval based on an external measure, and to distinguish such changes from random response errors. METHODS: In our application, eighty participants completed the Symptoms of Illness Checklist (SIC) on two occasions, two weeks apart, immediately before interviews given on each occasion by one of two physicians in a crossover design. The physician interview scores served as external measures, and structural equation modeling was used to estimate the parameters of a model that corrected for the occasion-specific effect of participants' responses using information from the interviews. RESULTS: Correcting for changes in symptoms during the test-retest interval increased SIC test-retest reliability from .744 to .804 and significantly improved model fit (chi2(diff)(1) = 30.78, p < .001). CONCLUSIONS: The results suggest methods that can improve the evaluation of self-report health questionnaire test-retest reliability by identifying changes using an external measure, and distinguishing these from random response errors; these increased the estimated SIC test-retest reliability and indicated that the SIC was indeed able to measure changes over the studied time interval. This method can be applied across a broad range of questionnaires.  相似文献   
105.
用橡胶木粉填充线性低密度聚乙烯(LLDPE),研究了酸、碱溶液预处理木粉的效果和硅烷偶联荆(KH-570)、MMA接枝的天然橡胶胶乳(MGL-30)两种改性剂对橡胶木粉表面改性的效果,以及未粉粒径和填充量等对木粉/LLDPE复合材料力学性能的影响,并用SEM对复合材料拉伸断面的形态结构进行了分析。结果表明:木粉的拉径、木粉填充量和改性荆用量对复合材料的力学性能有较大的影响,经碱溶液预处理再用改性荆改性后的木粉能有效地改善木粉与LLDPE的界面粘结强度,提高橡胶木粉/LLDPE复合材料的力学性能。  相似文献   
106.
目的评估丙戊酸钠治疗偏头痛持续状态的有效性和安全性。方法我们前瞻性地用静脉滴注丙戊酸钠来治疗偏头痛持续状态,然后比较患者治疗前与出院时视觉模拟评分(VAS)。并比较各种因素(一般情况,累计的丙戊酸钠剂量,合并用药)与治疗之间的关系。结果首次治疗中,26次(74.3%)治疗时患者VAS评分较治疗前减少50%或50%以上。所有治疗中,37次(82.2%)治疗使患者VAS评分较治疗前减少50%或50%以上。患者的性别与治疗反应无关。所有治疗中,合并用药(强痛定,索密通,散粒痛和达宁)和治疗时间与治疗反应呈负相关。仅3例(8.6%)出现短暂性眩晕。结论丙戊酸钠静滴是快速,有效和安全的止痛治疗。它对偏头痛持续状态有效。  相似文献   
107.
目的比较山莨菪碱联合无创正压面罩通气(654-2+NIPPV)和传统机械通气(CMV)治疗急性呼吸窘迫综合征(ARDS)的临床效果,评估山莨菪碱联合无创正压通气在ARDS治疗中的作用。方法将各种原因所致ARDS患者42例随机分为654-2+NIPPV组(21例)和CMV组(21例),在给予病因治疗同时分别实施654-2+NIPPV和CMV。观察分析两组患者在治疗过程中动脉血气变化、并发症的发生率及治疗效果。结果654-2+NIPPV组有8例(38.1%)治疗失败转为气管插管实行CMV,其中6例(28.6%)死亡。CMV组死亡7例(33.3%),两组病死率无显著差异(P〉0.05)。两组治疗有效的患者在分别接受654-2+NIPPV和CMV治疗后1h和6h动脉血气有相似的显著改善。654-2+NIPPV组患者机械通气时间和住院时间短于CMV组(P〈0.05)。654-2+NIPPV组的并发症发生率低于CMV组(P〈0.05)。结论在经过选择的ARDS患者中,应用654-2+NIPPV治疗的临床效果与CMV相似。实施654-2+NIPPV可缩短机械通气和住院时间,减少并发症。654-2+NIPPV可作为经过选择的ARDS患者首选的通气支持治疗手段。  相似文献   
108.
本文报道了169例中、老年普外科非急诊入院患者营养状况调查,多参数指标包括人体测量和实验室检查。结果显示40%患者有不同程度的营养不良。120例(71%)患者在8项调查指标中,有2~6项异常。按消化道和非消化道疾病进行比较,体重身高指数(WT/HT)、上臂周径(AMC)在中年组有显著差异(P<0.05)。  相似文献   
109.
黎勇 《中国药房》1992,3(5):27-28
本文论述了医院药剂科的法律地位和作用,药政部门的执法盲点,提出法律措施是促使医药同步发展的可靠保障。  相似文献   
110.
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