全文获取类型
收费全文 | 101898篇 |
免费 | 9825篇 |
国内免费 | 6519篇 |
专业分类
耳鼻咽喉 | 954篇 |
儿科学 | 1154篇 |
妇产科学 | 1038篇 |
基础医学 | 11534篇 |
口腔科学 | 1917篇 |
临床医学 | 12048篇 |
内科学 | 14563篇 |
皮肤病学 | 1271篇 |
神经病学 | 5184篇 |
特种医学 | 4337篇 |
外国民族医学 | 47篇 |
外科学 | 11347篇 |
综合类 | 18048篇 |
现状与发展 | 19篇 |
一般理论 | 2篇 |
预防医学 | 7152篇 |
眼科学 | 2464篇 |
药学 | 10598篇 |
91篇 | |
中国医学 | 6317篇 |
肿瘤学 | 8157篇 |
出版年
2024年 | 258篇 |
2023年 | 1184篇 |
2022年 | 3023篇 |
2021年 | 4659篇 |
2020年 | 3445篇 |
2019年 | 3065篇 |
2018年 | 3278篇 |
2017年 | 3113篇 |
2016年 | 3120篇 |
2015年 | 4541篇 |
2014年 | 5675篇 |
2013年 | 5635篇 |
2012年 | 8414篇 |
2011年 | 8989篇 |
2010年 | 6341篇 |
2009年 | 5399篇 |
2008年 | 6431篇 |
2007年 | 6167篇 |
2006年 | 5746篇 |
2005年 | 5054篇 |
2004年 | 4013篇 |
2003年 | 3828篇 |
2002年 | 3369篇 |
2001年 | 2510篇 |
2000年 | 2181篇 |
1999年 | 1794篇 |
1998年 | 1045篇 |
1997年 | 1053篇 |
1996年 | 827篇 |
1995年 | 699篇 |
1994年 | 588篇 |
1993年 | 394篇 |
1992年 | 436篇 |
1991年 | 374篇 |
1990年 | 296篇 |
1989年 | 253篇 |
1988年 | 206篇 |
1987年 | 169篇 |
1986年 | 145篇 |
1985年 | 127篇 |
1984年 | 76篇 |
1983年 | 61篇 |
1982年 | 30篇 |
1981年 | 29篇 |
1980年 | 24篇 |
1979年 | 28篇 |
1978年 | 16篇 |
1976年 | 16篇 |
1974年 | 16篇 |
1969年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
用放射配体结合分析法分别测定了正常组、特布他林组、特布他林十曲尼司特组豚鼠的肺组织β受体最大结合力和解离常数,结果显示:给特布他林后豚鼠肺组织β受体发生明显的向下调节.曲尼司特可预防此向下调节的发生. 相似文献
82.
83.
84.
本文对17例肾病综合征(NS)患儿和15例健康对照组儿童血红细胞磷脂过氧化氢谷胱甘肽过氧化物酶(PHGPx)活力,脂溶性荧光色素(LSFP)含量进行了研究。结果表明,NS急性期PHGPx活力明显降低.LSFP含量增加;恢复期PHGPx活力较急性期明显提高,但仍低于正常对照组,LSFP虽较急性期下降,但仍高于正常对照组。说明NS存在PHGPx和LSFP的改变,但可逐渐恢复。 相似文献
85.
111例双黄连过敏反应文献分析 总被引:9,自引:0,他引:9
目的:分析临床应用双黄连引致的过敏反应的规律。方法:对2000年1月-2004年3月中国期刊网中收录的111例双黄连过敏反应在性别、年龄、发生时间、给药途径和临床表现进行分析。结果:双黄连过敏与年龄、性别无关,与给药途径有关,注射剂易发生过敏反应。该药过敏的临床表现有:过敏性休克67例(60%),皮肤黏膜症状61例(55%),其他类型过敏反应14例(13%)31例同时出现多种过敏症状。过敏发生时间最短为开始用药1m in以内,最长为用药后72h,97例(87%)在用药过程中发生过敏症状。结论:双黄连的过敏反应以速发型过敏反应(如过敏性休克)为主,应是临床关注的重点。 相似文献
86.
M K Song W Y Shin N F Adham N V Costea 《The American journal of clinical nutrition》1989,49(4):701-707
The effects of different amounts of dietary zinc on the Zn absorption rate and on Zn, calcium and magnesium concentrations in tissues of MOPC 104E tumor-bearing Balb/c mice were determined. The Zn absorption rate was inversely related to the amounts of Zn in their diets and was lower than that of nontumor-bearing control mice fed a laboratory mice chow. Zn concentrations of tumor-bearing mice were also low compared with control mice but tumor Zn concentrations, regardless of the concentrations of Zn in the diets, were higher than those of normal tissues of the host other than the pancreas. Ca concentrations in tumor and tissues of tumor-bearing mice were higher than in control animals but Mg concentrations in tissues of tumor-bearing mice appeared to be similar to those of control mice. Results suggest that tumor-bearing mice have a lower intestinal Zn absorption capacity and a higher Zn uptake rate causing other tissues to become hypozincemic and hypercalcemic. 相似文献
87.
Detection of cell apoptosis by MTT assay.] 总被引:1,自引:0,他引:1
Chun-Qiong Feng Wen-Li Ma Yan-Bing Song Qiu-Ye Guo Qing-Hua Wu Wen-Ling Zheng 《第一军医大学学报》2002,22(3):262-263
OBJECTIVE: To study the feasibility of using MTT assay to detect cell apoptosis. METHODS: K562 cells were grown in RPMI 1640 medium supplemented with 10% calf serum and 4 micromol/L arsenic trioxide. Apoptosis was induced in the cultured cells by As2O3, and the cells were detected with optical microscope, DNA gel electrophoresis and MTT staining respectively. RESULT: MTT staining could also accurately detect cell apoptosis, by which the apoptotic cells were easily distinguished from normal cells and dead cells. CONCLUSION: MTT staining is simple, convenient and practical for detecting cell apoptosis. 相似文献
88.
目的:观察银杏竹鼠肌肉成分对小鼠智力体力的影响。方法:小鼠随机分为七组,通过喂饲银杏竹鼠肌肉干粉连续一个月,用小鼠低温游泳存活时间实验,耐缺氧实验及跳台和记忆获得障碍实验分别记录低温游泳存活时间,缺氧存活时间及第一次错误潜伏期和跳台错误次数。结果:各竹肉组小鼠与普通饲料(NS)组,普肉组,护宝液组比较,均可明显延长小鼠低温游泳存活时间和缺氧存活时间(P<0.05),与洋参丸组相当(P>0.05),竹肉大/超组小鼠跳台错误次数均减少(P<0.05),竹肉超组小鼠第一次错误潜伏期延长(P<0.05),竹肉大组小鼠第一次错误潜伏期有延长趋势,但无统计学意义。结论:口服银杏竹鼠肌肉成分可增强小鼠学习记忆能力,增强小鼠体质,提高小鼠生活质量。这一结果也提示银杏竹鼠肌肉成分很有可能成为极有应用前景和开发前景的保健食品。 相似文献
89.
去势后大鼠海马结构一氧化氮合酶阳性神经元的变化 总被引:8,自引:1,他引:7
目的:观察去势后大鼠海马结构一氧化氮合酶(NOS)阳性神经元的变化。方法:用黄递酶组织化学染色方法观察切除双侧卵巢后雌后SD大鼠海马结构NOS阳性神经元的形态,分布的变化,并进行计算机图像分析。结果:去势后海马结构NOS阳性神经元分布变化有区域差异性;NOS阳性神经元在下托、海马(CA)一区邻近下托的部分、CA三区、CA四区(CA4)和齿状回(DG)数目明显减少,而在CA二区数目明显明显增多,CA4和DG的NOS阳性神经元平均密度降低,胞体的平均周长和平均截面积都明显减少。结论:雌激素可能通过影响海马结构NOS的表达来影响学习和记忆。 相似文献
90.
In order to clarify the reported discrepancies in S100 alpha protein and mRNA distribution in rat tissues, a rat S100 alpha cDNA has been isolated and this species homologous probe along with a rat S100 beta cDNA probe has been used to examine S100 mRNA expression in rat tissues. Although the rat S100 alpha cDNA was missing approximately 30 nucleotides of coding sequence, only 4 conservative changes in amino acid sequence were observed when the deduced amino acid sequence was compared to the bovine S100 alpha amino acid sequence. Thus, S100 alpha proteins, like S100 beta proteins, are highly conserved among species. All nineteen of the tissues examined (including cerebrum and cerebellum) contained S100 alpha mRNA. In addition, S100 beta mRNA was detected in thirteen of the nineteen tissues examined. These results are in agreement with previous protein distribution studies and further demonstrate that S100 proteins are not brain-specific and are expressed in a large number of tissues. Although S100 alpha and S100 beta mRNAs were detected in rat tissues which had previously been reported to contain S100 alpha and S100 beta protein, a direct correlation between the protein and mRNA levels were not observed, suggesting that different mechanisms regulate S100 expression in various tissues. S100 alpha exhibited a single similar size mRNA species (0.5 Kb) in all tissues examined, as did S100 beta (1.5 Kb), suggesting that the individual S100 proteins are expressed as single mRNA and protein products in rat tissues. 相似文献