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   60579篇
  免费   5802篇
  国内免费   3380篇
耳鼻咽喉   512篇
儿科学   872篇
妇产科学   1004篇
基础医学   6993篇
口腔科学   1077篇
临床医学   7095篇
内科学   9734篇
皮肤病学   736篇
神经病学   2890篇
特种医学   2520篇
外国民族医学   34篇
外科学   7289篇
综合类   9055篇
现状与发展   15篇
一般理论   16篇
预防医学   3866篇
眼科学   1486篇
药学   6485篇
  51篇
中国医学   3077篇
肿瘤学   4954篇
  2024年   147篇
  2023年   772篇
  2022年   1803篇
  2021年   2849篇
  2020年   2049篇
  2019年   1885篇
  2018年   2028篇
  2017年   1805篇
  2016年   1792篇
  2015年   2487篇
  2014年   3153篇
  2013年   3174篇
  2012年   4448篇
  2011年   4723篇
  2010年   3065篇
  2009年   2512篇
  2008年   3361篇
  2007年   3425篇
  2006年   3173篇
  2005年   2958篇
  2004年   2392篇
  2003年   2208篇
  2002年   1999篇
  2001年   1665篇
  2000年   1596篇
  1999年   1441篇
  1998年   771篇
  1997年   777篇
  1996年   630篇
  1995年   530篇
  1994年   463篇
  1993年   313篇
  1992年   506篇
  1991年   412篇
  1990年   388篇
  1989年   345篇
  1988年   274篇
  1987年   252篇
  1986年   202篇
  1985年   160篇
  1984年   117篇
  1983年   84篇
  1982年   60篇
  1981年   73篇
  1980年   39篇
  1979年   72篇
  1978年   37篇
  1974年   36篇
  1973年   33篇
  1972年   41篇
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
131.
支气管结核在纤维支气管镜下治疗方法的探讨   总被引:2,自引:2,他引:0  
目的 :探讨支气管结核在纤维支气管镜下治疗的方法及价值。方法 :对 2 5例支气管结核病人 ,在全身抗结核治疗的同时分别实施镜下注药治疗、微波接触式辐射治疗和球囊扩张术 局部注药治疗。结果 :在全身抗结核治疗的同时运用上述几种镜下治疗方法 ,支气管局部病灶较镜下治疗前均有明显好转。结论 :利用纤维支气管镜对支气管结核病人进行局部治疗 ,可加快病灶的吸收和症状的改善 ,值得推广应用  相似文献   
132.
左旋氨氯地平治疗轻中度高血压疗效及不良反应的临床研究   总被引:14,自引:0,他引:14  
目的:为评价左旋氨氯地平降压疗效及不良反应,并与氨氯地平相比较。方法:采用随机分组平行对照方法,将120例轻、中度高血压患者分成左旋氨氯地平组(60例),口服2.5~5mg·d~(-1)和氨氯地平组(60例),口服5~10mg·d~(-1)。观察5周。每周一次上午延迟1~4小时用药并测诊室谷值坐位血压、心率、观察不良反应。结果:5周未左旋氨氯地平与氨氯地平组治疗有效反应率分别为86.7%和83.3%,每组治疗前后比较差异非常显著(P<0.01)。组间比无显著性差异(P>0.05)。左旋氨氯地平组不良反应发生率6.7%,氨氯地平组为16.7%(P>0.05),但试验组不良反应程度更轻微。结论:左旋氨氯地平与氨氯地平治疗高血压同样有效,不良反应可能更小。  相似文献   
133.
医用电气设备和系统电磁兼容性抗干扰设计方案的研究   总被引:1,自引:0,他引:1  
依据现有电磁兼容性及医用电气设备安全通用要求的相关标准,主要从接地、屏蔽和滤波三个方面对我国现阶段医用电气设备和系统的电磁兼容性抗干扰设计方案进行探讨,希望借此为医用电气设备电磁兼容性的推广做一些有益的探索.  相似文献   
134.
Adult male rats were fed on diets containing 100 g dietary fibre/kg either as alpha-cellulose or wheat bran or the pericarp-seed coat or aleurone layers prepared from that bran by sequential milling and air elutriation and electrostatic separation. After 10 d, concentrations of total volatile fatty acids (VFA) in caecal fluid were significantly different between groups and fell in the order: aleurone greater than wheat bran greater than pericarp-seed coat greater than cellulose. This ranking probably reflected the ease of fermentation of fibre polysaccharides by colonic bacteria which also resulted in a considerably higher faecal bacterial mass in the aleurone group. Because of the differences in the volume of caecal digesta, the mass of caecal VFA was considerably the highest in the aleurone group, intermediate with wheat bran and equally low in the pericarp-seed coat and cellulose groups. The diet based on aleurone gave a relatively higher proportion of propionate but with both pericarp-seed coat and wheat bran the contribution of butyrate was raised. VFA concentrations in hepatic portal venous plasma were proportional to caecal concentrations with very high (greater than 3 mM) values being recorded in the aleurone group. The findings are discussed in relation to the apparent susceptibility of the morphological components of wheat bran to fermentation by large bowel bacteria.  相似文献   
135.
4-Aminopyridine (4-AP) induced an atropine- and tetrodotoxin (TTX)-insensitive contraction (resistant contraction), in a concentration-dependent manner, in the isolated jejunum of rabbits. The failure of specific antagonists of histamine, serotonin and substance P to affect this resistant contraction ruled out the participation of histamine, serotonin and/or substance P. Antiserum against neuropeptide Y (NPY) reduced this resistant contraction in a concentration-dependent manner and inhibited the action of 4-AP totally at a high concentration (1.25% dilution) whereas normal serum lacked this ability. This suggested that the release of NPY was involved in this 4-AP-induced resistant contraction. Radioimmunoassay of NPY-like immunoreactivity in isolated synaptosomal preparations indicated that 4-AP possessed the ability to induce the release of NPY. However, guanethidine did not affect the actions of 4-AP, indicating that NPY is released mainly from non-adrenergic nerves. Our results indicate that 4-AP induces the release of NPY from non-adrenergic nerves to produce an atropine- and TTX-resistant contraction in the isolated jejunum of rabbits.  相似文献   
136.
We have previously reported that the J774A.1 macrophage-like tumor cell line produces two potent monokines which stimulate the growth of osteoblasts and chondrocytes. These growth factors, which have an affinity for heparin-agarose, have been termed HEP I (a 30 Kd PDGF-like molecule) and HEP II (an approximately 20 Kd molecule), respectively, based on their elution profile. Unlike HEP I, HEP II does not stimulate the growth of fibroblasts. Extensive biological and chromatographic studies disclosed that HEP II appears to be a unique bone cell mitogen unlike any known growth factor, including the FGFs, IL-1s, and TNFs, EGF, IGF-I and -II, TGF-beta, beta 2 microglobulin, G-CSF, CSF-1 and GM-CSF. To characterize more fully the effects of the macrophage-derived monokines on osteoblast growth and function, clones were derived from calvaria explant cultures. Two clones, SDFRC-2.05 and SDFRC-3, were developed and found to exhibit osteoblastic characteristics, including high levels of alkaline phosphatase, synthesis of type I but not type III collagen, and an increased intracellular cAMP production in response to PTH. The SDFRC-3 cells exhibited a polygonal morphology like that of the explant-derived cells while SDFRC-2.05 cells exhibited a more fibroblastic morphology. When tested on the explant cultures and clones, HEP I and HEP II were found to stimulate DNA synthesis and increase protein per culture, but decreased alkaline phosphatase activity. Clone SDFRC-3 was found to be more responsive to HEP II than clone SDFRC-2.05. Both monokines were found to be more potent mitogens for bone cells than TGF-beta. HEP II, but not HEP I or TGF-beta, induced a transformation of bone cells from a polygonal to a fibroblastic morphology, suggesting the induction of migration prior to proliferation. Thus, macrophages may be responsible not only for bone repair but also for ensuring the linkage of bone formation to resorption during physiological remodeling.  相似文献   
137.
138.
深圳市福田区暗娼艾滋病KAP调查分析   总被引:1,自引:0,他引:1  
目的:探讨暗娼艾滋病KAP的现状,为艾滋病预防控制中的咨询、外展及其它健康教育活动提供依据。方法:在“城中村”中随机抽取55位暗娼,由经过专门培训的调查员调查并采血检验。结果:暗娼艾滋病平均知晓率为73.88%;与艾滋病相关的高危行为,呈现低龄化、职业化的倾向;为了预防艾滋病,绝大部分暗娼愿意坚持使用安全套,但实际情况并不如人意;暗娼获得艾滋病知识及相关服务并不方便;梅毒检出率为9.09%。结论:打工者的性权利长期被忽视,使卖淫拥有很大的市场,这是暗娼们乃以存在并长久不衰的重要原因之一;暗娼艾滋病知晓率有了较大提高,可能与深圳市开展艾滋病防制工作较早、力度较大有关;安全套使用率还有待提高:艾滋病外展服务亟待开展与加强。  相似文献   
139.
The current report focuses on two patients of the same age who presented similar appearances on initial anteroposterior chest images. Follow-up images showed superoanterior and superoposterior mediastinal lesions. The first patient with noninvasive cystic thymoma was suspected before surgery, while the pathologic diagnosis was intrathoracic phrenic nerve schwannoma. The second patient was with an asymmetric, dumbbell-shaped paravertebral tumor over T3 and T4 on the left side. The preoperative…  相似文献   
140.
目的 探讨绝经后妇女IUD取器前超声测定环距是否与取器难度有关.方法 对放置IUD绝经后妇女取器前行超声测定环距,分环距>1.5cm,1.5-1.0cm,≤1.0cm三组,比较手术难度,并对绝经≤12月IUD组与对照组的围绝经期综合症、老年性阴道炎、阴道炎、子宫蒌缩情况进行分析.结果 环距≤1cm组手术难度显著增加(P<0.05).绝经≤12个月IUD组与对照组在围绝经综合症、老年性阴道炎、阴道炎、子宫萎缩发生率方面均无显著差异,(P>0.05).结论 绝经后妇女取器前超声测定环距对估计手术难度有一定意义,尤其当环距≤1cm,手术困难明显增加.绝经≤12月IUD对健康没有直接影响.  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