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   69111篇
  免费   4779篇
  国内免费   947篇
耳鼻咽喉   429篇
儿科学   1547篇
妇产科学   779篇
基础医学   3250篇
口腔科学   1346篇
临床医学   8033篇
内科学   6856篇
皮肤病学   758篇
神经病学   4004篇
特种医学   1104篇
外科学   4430篇
综合类   13717篇
现状与发展   1篇
一般理论   2篇
预防医学   9745篇
眼科学   395篇
药学   9732篇
  189篇
中国医学   5241篇
肿瘤学   3279篇
  2024年   149篇
  2023年   1187篇
  2022年   2259篇
  2021年   3203篇
  2020年   3043篇
  2019年   2591篇
  2018年   2407篇
  2017年   2627篇
  2016年   2892篇
  2015年   2821篇
  2014年   7145篇
  2013年   6545篇
  2012年   5894篇
  2011年   5647篇
  2010年   4162篇
  2009年   3252篇
  2008年   2996篇
  2007年   2738篇
  2006年   2140篇
  2005年   1604篇
  2004年   1278篇
  2003年   1068篇
  2002年   847篇
  2001年   711篇
  2000年   656篇
  1999年   491篇
  1998年   418篇
  1997年   342篇
  1996年   277篇
  1995年   276篇
  1994年   233篇
  1993年   199篇
  1992年   152篇
  1991年   140篇
  1990年   120篇
  1989年   136篇
  1988年   110篇
  1987年   96篇
  1986年   90篇
  1985年   210篇
  1984年   264篇
  1983年   220篇
  1982年   233篇
  1981年   202篇
  1980年   164篇
  1979年   163篇
  1978年   113篇
  1977年   72篇
  1976年   81篇
  1975年   72篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
141.
陈坤  邹艳  王建跃  张立军 《营养学报》2003,25(3):239-244
目的 : 海岛学生饮食结构中含有碘丰富的海产品。本研究旨在了解海岛学生的碘营养状况 ,评价食盐补碘的利弊。方法 : 对定海农村 (食用碘盐 )和岱山农村 (不食用碘盐 )的学校中随机抽取的 1 2个班级 ,对碘盐组和非碘盐组的饮食碘摄入和尿碘水平等变量进行描述 ,并分别以尿碘和甲状腺肿率为应变量进行单因素和多因素回归分析。结果 : 碘盐组除碘盐外每日碘摄入量中位数为 1 84μg,而不食用加碘盐的组为 1 0 5 μg,两组饮食碘摄入有显著性差异 (u=4.71 0 ,P=0 .0 0 0 ) ,而尿碘水平在食用碘盐组和不食用碘盐组分别为 1 6 9μg/L和 1 2 9μg/L,两组间有显著性差异 (u=6 .3 0 2 ,P=0 .0 0 0 )。多因素分析中性别和是否食用碘盐对尿碘水平有显著性意义 (P<0 .0 5 ,OR值分别为 0 .76 5 ,1 .93 3 )。甲状腺肿学生和正常学生的饮食碘和尿碘无统计学差异 (P>0 .0 5 )。Poisson回归分析中性别和是否食用碘盐对甲状腺肿率有影响 (P<0 .0 5 ,OR值分别为2 .2 5 ,3 .5 2 )。结论 : 舟山海岛学生要注意补碘过程中可能出现的碘过量问题。  相似文献   
142.
The dietary history method was used to determine the total energy and macronutrient intake, the distribution of daily energy from the different meals and the energy contribution of various food groups, in a population of 299 boys, aged between 10 and 15 years. The effects of age, the social status of the father (SPS), the ponderal index, the importance of breakfast or lunch, and the level of energy intake on dietary indicators, were studied. In our population, energy intake increased with increasing age but the energy contribution of macronutrients did not vary. The diet of boys whose fathers were in the upper SPS classes differed from the diet of those boys whose fathers were manual workers: for example they consumed less energy and pastries, but more animal protein (in percentage of energy intake), more dairy products, and more fruit. The ponderal index was negatively related to energy intake but positively related to protein intake, especially from meat and meat products. The energy intake from protein, animal protein and the energy contribution of dairy products, meat and meat products, fish and vegetables was lower among large eaters than among small eaters. The energy contribution of pastries, sugar and sweets was higher among large eaters.
Similarily, the energy intake from morning and evening snacks was also higher among large eaters. It should be noted that boys who had a substantial breakfast took in less energy from all other meals (including snacks and main meals). Such informaton is necessary in order to develop an effective health programme.  相似文献   
143.
原发性腹膜后脂肪肉瘤20例报告   总被引:1,自引:0,他引:1  
林秉勋  林小军 《癌症》1993,12(5):440-442
自1965年5月至1991年7月共收治原发性腹膜后脂肪肉瘤20例,均经手术及病理证实。20例中完全切除者15例,部分切除者4例,活检1例。肿瘤切除合并肾,肠襻等邻近器官切除者达12例。全组的5年,10年生存率分别是57.1%和20.0%,完全切除组的5年10年生存率分别是63.6%和28.6%。20例病人共进行了48次切除手术。首次手术死亡2例。着重讨论了本病的诊断、治疗和突出的临床特点。  相似文献   
144.
BACKGROUND: In maintenance haemodialysis patients, daily food intake is changeable; however, its relationship with nutritional status is unexplored. This study aimed to evaluate the isolated, long-term effect of daily nutrient intake on nutritional status in haemodialysis patients. METHODS: We performed a prospective 1-year controlled study in 27 chronic haemodialysis patients, without recognized risk factors for malnutrition. Each day for 1 week, four times in the year, we measured protein nitrogen appearance, and assessed dietary protein (DPI) and energy (DEI) intake from dietary diaries. We compared the nutritional outcome of patients spontaneously reducing nutrient intake below the threshold of 0.8 g/kg body weight/day for DPI and 25 kcal/kg body weight/day for DEI during the week (LOW, n = 8), with controls at adequate nutrient intake (CON, n = 19). An interventional 6-month study was then carried out in LOW to verify the cause-effect relationship. RESULTS: All patients showed a day-by-day reduction of whole nutrient intake during interdialytic period, which was mostly relevant in the third interdialytic day (L3). During the 1-year study, even in the presence of adequate dialysis dose and normal inflammatory indexes, body weight (68.0 +/- 5.5 to 65.8 +/- 5.9 kg), serum albumin (3.96 +/- 0.07 to 3.66 +/- 0.06 g/dl) and creatinine (9.2 +/- 1.1 to 8.1 +/- 0.7 mg/dl) significantly decreased in LOW but not in CON. Diaries evidenced in LOW a reduced number of meals at L3 that was explained by the fear of excessive interdialytic weight gain. During the interventional study, daily DPI and DEI increased at L3; this was associated with a significant increment of body weight, and serum albumin and creatinine levels. CONCLUSIONS: In maintenance haemodialysis patients the persistent, marked reduction of daily nutrient intake, even if limited to a single day of the week, is an independent determinant of reversible impairment of nutritional status.  相似文献   
145.
本科自 2 0 0 0年 6月以来 ,采用颈动脉加压注射复方维脑路通合剂治疗脑梗死 180例 ,并与静脉给药组相比较 ,现总结如下。1 资料与方法1.1 临床资料 治疗组 180例 ,男 117例 ,女 6 3例 ,年龄 37岁~ 76岁 ,平均年龄 5 7.2 0岁。均为颈内动脉系统脑梗死。其中大面积脑梗死 4例 ,脑梗死 85例 ,腔隙性脑梗死 91例。大面积脑梗死组 4例 ,其梗死灶涉及 2个脑叶或以上 ,均无意识障碍及脑疝者 ,在发病 10d后即脑水肿高峰期后开始颈动脉加压注射。治疗组病例选择除下列禁忌 :①严重高血压病(血压≥ 2 6 .6 / 16kPa) ;②脑出血、出血性梗死 ;③严…  相似文献   
146.
目的 探讨对小儿难治性惊厥持续状态的有效治疗方法。方法 对14例小儿难治性惊厥持续状态采用硫喷妥钠治疗并观察疗效。结果 硫喷妥钠治疗有效率为100%,1例出现呼吸抑制,3例于停药后复发。结论 硫喷妥钠对小儿难治性惊厥持续状态有明显疗效,但易发生呼吸抑制。惊止后应维持一段时间,以免复发。  相似文献   
147.
宁夏卫生人力资源现状分析   总被引:6,自引:0,他引:6  
目的 了解宁夏卫生人力现状 ,提出建设性意见。方法 采用普查分类统计分析的方法。结果 现有卫生人员 2 3485名 ,其中卫生专业技术人员 18838名 ,每千人拥有 4 .35名卫生人员和 3.36名卫生专业技术人员。结论 年龄和职称分布合理 ,卫生人力资源总量较 16年前明显增加 ,卫生专业技术人员增长了 83.5 7% ,研究生偏少 ,本科学历比例较小 ,卫生人力资源过于集中在银川市  相似文献   
148.
Background: Elder patients with acute coronary syndromes (ACS) are less likely to receive cardiac catheterization. The reasons for this are unclear.
Objectives: To assess whether elder patients who had a documented history of dementia, lived in extended care facilities, or had do not intubate–do not resuscitate (DNR-DNI) advance directives were less likely to receive cardiac catheterization, despite having ACS with high-risk features.
Methods: This was a medical record review conducted at an urban teaching hospital. DNR-DNI status before hospitalization, extended care facility (nursing home or assisted living) residence, and a previous diagnosis of dementia were obtained from the medical record. Patients 65 years and older who presented to the emergency department with acute myocardial infarction or with unstable angina with ST segment deviation were included. Univariate and multivariate logistic regression were performed, and odds ratios (ORs) were reported with their 95% confidence intervals (CIs).
Results: Of the 201 eligible patients, 66 (32.8%) patients did not undergo cardiac catheterization. In the univariate analysis, patients who had dementia, resided in extended care facilities, or were DNR-DNI were less likely to receive cardiac catheterization. Only extended care facility residence (OR, 0.18; 95% CI = 0.04 to 0.83) and DNR-DNI status (OR, 0.19; 95% CI = 0.04 to 0.92) remained significantly associated with decreased cardiac catheterization in the multivariate analysis.
Conclusions: Elder patients with ACS residing in extended care facilities or who are DNR-DNI are less likely to receive cardiac catheterization. Future studies concerning the quality of ACS care for elders should take these variables into account.  相似文献   
149.
中国原发性肝癌临床分期预测肝癌肝移植预后的临床研究   总被引:2,自引:0,他引:2  
目的评价“中国原发性肝癌临床分期”对肝癌肝移植疗效的预测价值。方法对1993年4月至2003年1月我科59例采用肝移植治疗的肝癌病人临床资料进行回顾性分析,按中国原发性肝癌临床分期原则进行分期,比较各期间肝癌肝移植疗效。结果Ⅰb、Ⅱa、Ⅱb、Ⅲa和Ⅲb期移植术后1年生存率分别为83·33%、66·67%、50·00%、35·71%和16·67%,各期间术后累计生存率有统计学差异(P<0·01);Ⅰb~Ⅱb和Ⅲa~Ⅲb期移植术后1年生存率分别为66·67%和25·00%,2年生存率分别为45·71%和25·00%,两组间术后累计生存率有统计学差异(P<0·05)。结论中国原发性肝癌临床分期适用于肝癌肝移植术前分期。  相似文献   
150.
目的评价不同治疗方法对慢性牙周炎的临床效果。方法对90例慢性牙周炎患者,随机分成三组:龈上洁治术 抗生素组(A组),单纯龈上洁治术组(B组)和单纯抗生素组(C组)。分别给予不同的治疗,在治疗后1周、2周和4周记录牙周袋探诊深度(PPD)、探诊附着水平(PAL)、菌斑指数(PLI)、龈沟出血指数(SBI)。结果治疗1周和2周后各指标显著减轻(P<0.05),2周比1周减轻更明显(P<0.05),4周与2周比较无明显差异(P>0.05),A组各指标减轻比B组显著(P<0.05);B组比C组疗效显著(P<0.05)。结论A组作用优于B组(P<0.05),B组优于C组(P<0.05)。  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