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   26846篇
  免费   2767篇
  国内免费   765篇
耳鼻咽喉   172篇
儿科学   489篇
妇产科学   231篇
基础医学   1083篇
口腔科学   630篇
临床医学   3968篇
内科学   2169篇
皮肤病学   183篇
神经病学   844篇
特种医学   603篇
外国民族医学   7篇
外科学   1482篇
综合类   3547篇
现状与发展   1篇
一般理论   1篇
预防医学   8226篇
眼科学   119篇
药学   3528篇
  79篇
中国医学   2185篇
肿瘤学   831篇
  2024年   111篇
  2023年   635篇
  2022年   938篇
  2021年   1759篇
  2020年   1413篇
  2019年   1075篇
  2018年   1032篇
  2017年   1054篇
  2016年   1177篇
  2015年   1200篇
  2014年   1992篇
  2013年   2377篇
  2012年   1761篇
  2011年   1768篇
  2010年   1379篇
  2009年   1302篇
  2008年   1219篇
  2007年   1159篇
  2006年   1036篇
  2005年   820篇
  2004年   727篇
  2003年   608篇
  2002年   474篇
  2001年   446篇
  2000年   350篇
  1999年   342篇
  1998年   283篇
  1997年   240篇
  1996年   200篇
  1995年   180篇
  1994年   166篇
  1993年   145篇
  1992年   144篇
  1991年   110篇
  1990年   100篇
  1989年   92篇
  1988年   94篇
  1987年   52篇
  1986年   60篇
  1985年   76篇
  1984年   65篇
  1983年   30篇
  1982年   33篇
  1981年   31篇
  1980年   34篇
  1979年   14篇
  1978年   19篇
  1977年   16篇
  1975年   10篇
  1973年   6篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
131.
高等教育大众化对质量的关注是必然的.高等教育评估制度的建设是当前我国深化高等教育管理体制改革、保证高等教育健康发展的需要.我们要建立既符合中国国情又体现高等教育评估普遍规律的具中国特色的高等教育评估制度.  相似文献   
132.
去骨瓣减压术治疗大面积脑梗死的短期疗效评价   总被引:7,自引:1,他引:6  
目的:评价去骨瓣减压术治疗大面积脑梗死的效果。方法:制定入选和排除标准,统一术式,比较术前、术后不同时期的神经功能变化,并对存活病例进行随访(6个月),评价术后3和6个月时的预后评分(GOS)和BarthelIndex(BI)的变化。结果:按入选标准行去骨瓣减压术26例,术后死亡率为30.8%。术前昏迷评分GCS对决定手术时机有指导作用。共随访14例患者,术后3和6个月GOS分别为3.6±0.8和4.0±0.8,与出院时GOS评分比差异有统计学意义。术后3和6个月BI分别为68.9±29.4和77.5±28.3,其中术后6个月BI>60者占85.7%。结论:对保守治疗无效的大面积脑梗死患者,去骨瓣减压术不仅可作为一种“救命”手术,而且多数存活病例恢复较好。合理选择手术适应证、及时把握手术时机以及充分手术减压可能是影响预后的重要因素。  相似文献   
133.
主成份分析与因子分析用于多指标综合评价   总被引:9,自引:0,他引:9  
本文从应用角度阐明了主成份分析与因子分析用于多指标综合评价的异同点,并用实例加以说明。提出了主成份分析和因子分析用于多指标综合评价时,应在能明确主成份或因子的意义和方向情况下加权,否则会得到错误的结果。  相似文献   
134.
Sixty Sprague-Dawley rats were pair-fed one of three nutritionally identical diets. One diet contained “low-fiber” (3.8% crude fiber); the others contained “high fiber” (28.7% crude fiber) composed of either cellulose or lignin. Although both “high fiber” diets had similar stool bulking effects, only the cellulose diet was associated with a reduction in 1,2-dimethylhydrazine (DMH)-induced colon neoplasms. The cellulose diet was also associated with distinct changes in the gut bacterial profile and with a lowered serum cholesterol. © 1993 Wiley-Liss, Inc.  相似文献   
135.
Summary: Some of the properties of 4–bromobenzalde-hyde semicarbazone (compound IV), a prototype molecule of a new class of anticonvulsants, aryl semicarbazones, are described. Compound IV demonstrated activity in the maximal electroshock (MES) and subcutaneous pentylenetetrazol (scPTZ) tests in mice, with low neurotoxicity. When given orally to rats, it displayed high potency in the MES test and very low neurotoxicity, resulting in a high protective index (PI). Compound IV displayed no proconvulsant properties, and development of rapid tolerance was not noted. When administered intraperitoneally (i.p.) at doses of 100, 300, or 600 mg/kg to rats, compound IV had no effect on levels of γ-aminobu-tyric acid (GABA) or on GABA-T activity in whole brain. When tested in vitro, compound IV had no effect on rat brain GABA-T at a drug concentration of 100 μM. Although the activities of certain drug-metabolizing enzymes were increased after oral administration of compound IV to rats, these effects were less prominent than those of phenytoin (PHT) and carbamazepine (CBZ). The principal mode of action of compound IV does not appear to be an interaction with the GABAA receptor complex, and other mechanisms, involving excitatory amino acid neurotransmission, will have to be considered in future investigations of the anticonvulsant activity of this compound.  相似文献   
136.
The present trial was designed to evaluate clinical scores (single observer) of sodium lauryl sulphate (SLS)-induced skin irritation in a group of subjects (n = 10) over a 10-day period along with various skin function parameters. In order to avoid significant variations due to secondary phenomena, the following parameters were recorded with non-invasive instruments in this order: skin capacitance (C1; arbitrary units; CM420 Corneometer), transepidermal water loss (TEWL; g/m2.h; Evaporimeter) and laser Doppler flowmetry (CBFV: cutaneous blood flow values; Periflux). All examinations were performed during winter on reclined relaxed subjects present for at least 10 min in a test room with controlled temperature and relative humidity (t degrees: 19.5-20.7 degrees C and RH: 47.3-60.3%). The analysis of differential data (delta = value at tx-value before test; 2-way ANOVA) was made on single parameters as a function of site (volar forearm versus neck) and time (from 24 h after 48-h occlusion with 5% SLS up to 10 days later). The profile of erythema scores over time differed between neck and forearm, but the delta CBFV readings with the laser Doppler instrument did not detect significant site-time interactions. Roughness (blind evaluation with palpating finger) and capacitance readings (delta C1) showed significant differences between sites, but the profile over time was similar in both locations. delta TEWL did not differ according to anatomical location. The reason for different erythema scores on neck and forearm might be related to inherent regional variation of optical properties of the skin or to a substantial contribution of SLS-induced roughness to the readings of erythema.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
137.
抗衰老药物家蚕寿命测定法的研究   总被引:3,自引:0,他引:3  
陈传盈  胡斌 《中成药》1994,16(2):32-34
本实验表明,多种中药材,如香附子、花粉、党参、菟丝子、蛇床子等的提取液涂在桑叶上喂蚕,能显著延长蚕蛾寿命,但对家蚕幼虫龄期无明显影响。这种实验方法重演性好,如能进一步完善试验方法,将可用于筛选抗衰老药物的研究。  相似文献   
138.
139.
三种虾蛄肌肉营养成分分析及评价   总被引:6,自引:1,他引:5  
蒋霞敏  钱云霞  王春琳 《营养学报》2003,25(2):175-177,180
虾蛄俗称“虾爬子”,“螳螂虾”,“琵琶虾”、“小龙虾”等 ,隶属节肢动物门 ,甲壳纲 ,口足目 ,虾蛄科的经济海产动物 ,主要生活在近海浅滩泥质海底巢穴中 ,全国各地的沿海都有分布。近年来随着人们膳食结构的转变 ,虾蛄是深受人们喜爱的佳肴 ,也是出口创汇的水产品之一。对虾蛄 ,国内外均有研究 [1~ 6 ]。但对营养成分分析报道较少[7,8] 。本研究分别对三种虾蛄的基本营养成分、氨基酸、脂肪酸的组成和含量进行比较研究 ,为虾蛄的人工养殖和综合利用提供基础数据。1 材 料 与 方 法1 .1 材料  实验所用口虾蛄 ( Oratosquilla ora…  相似文献   
140.
Diarrheal diseases have a well recognized negative effect on children's growth, probably due in part to reduced dietary intake during illness. Previous studies have shown that the effects of diarrhea on dietary intake are greater among hospitalized children than among those observed in their homes. Breast milk intake does not change during diarrhea, however, so breast-fed children are less likely to reduce their total energy and nutrient intakes. Recent analyses of clinical studies found that acidosis and dehydration were most closely associated with reduced dietary intake of hospitalized patients. The implications of these and other studies for the dietary management of patients during and after diarrhea 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