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   462516篇
  免费   42391篇
  国内免费   30517篇
耳鼻咽喉   4324篇
儿科学   6115篇
妇产科学   6371篇
基础医学   51820篇
口腔科学   7970篇
临床医学   63892篇
内科学   65592篇
皮肤病学   5219篇
神经病学   22917篇
特种医学   17115篇
外国民族医学   235篇
外科学   43421篇
综合类   79846篇
现状与发展   107篇
一般理论   28篇
预防医学   33677篇
眼科学   12578篇
药学   49406篇
  540篇
中国医学   28567篇
肿瘤学   35684篇
  2024年   1532篇
  2023年   6855篇
  2022年   17669篇
  2021年   22566篇
  2020年   17073篇
  2019年   14641篇
  2018年   15167篇
  2017年   14248篇
  2016年   13253篇
  2015年   20583篇
  2014年   25733篇
  2013年   24276篇
  2012年   35554篇
  2011年   38919篇
  2010年   26181篇
  2009年   21090篇
  2008年   26734篇
  2007年   26270篇
  2006年   25511篇
  2005年   23697篇
  2004年   15633篇
  2003年   14124篇
  2002年   11989篇
  2001年   10069篇
  2000年   10279篇
  1999年   10317篇
  1998年   6126篇
  1997年   6176篇
  1996年   4826篇
  1995年   4343篇
  1994年   3619篇
  1993年   2331篇
  1992年   3044篇
  1991年   2622篇
  1990年   2270篇
  1989年   1989篇
  1988年   1671篇
  1987年   1423篇
  1986年   1172篇
  1985年   962篇
  1984年   560篇
  1983年   389篇
  1982年   256篇
  1981年   257篇
  1980年   200篇
  1979年   233篇
  1977年   98篇
  1974年   114篇
  1973年   89篇
  1972年   94篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
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   
93.
王福梅  朱瑞芳 《护理研究》2006,20(36):3352-3353
文章编号:1009-6493(2006)12C-3352-02麻醉药品的管理是医院管理工作的一项重要任务,如果管理有方,使用得当,可以治病;如果失之管理,使用不当,危害生命健康及社会治安。2005年8月3日,国务院颁布了《麻醉药品和精神药品管理条例》以来我院采取了各种有效的相关措施,保证了麻醉药品的合理使用,取得了良好的社会效益。现将我院严格管理麻醉药品的方法介绍如下。1严格建卡要管理好麻醉药品,首先要严格建卡,建卡时要手续齐全。1.1户口本病人的户口要在建卡医院管辖区内,如超出所管辖区,应有三级甲等医院的证明或肿瘤专病医院的证明及病历。1.2病…  相似文献   
94.
搭建基础平台是改传统三年制医学教学“1+1+1”模式为“1+1”模式,为以“市场为导向,就业为中心”的高职教学进行多向培养提供条件,既拓宽教学渠道,适应市场需求,解决学生就业问题,同时又有利于学校发展,符合教学新模式量展要求。  相似文献   
95.
本文阐明了对SPECT探头校正与调试的重要性,特别是对探头校正与调试的具体方法与步骤作了详细介绍.  相似文献   
96.
Acetylcholine (ACh) induces nasal congestion at low doses but decongestion at high doses. The current study investigated the vascular mechanisms underlying this biphasic nasal airway response in dogs. Collecting and outflow veins from anterior and posterior nasal venous systems and the septal mucosa (containing sinusoidal venous plexuses) were isolated. The in vitro isometric tension of the vascular segments was monitored to reflect vascular reactivity. Immunohistochemical localisation of reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase and endothelial nitric oxide synthase (eNOS) was performed. ACh did not affect the venous plexuses but contracted the anterior collecting vein and the outflow veins of both systems in a concentration-dependent manner; the responses were unaffected by nitro-L-arginine-methyl-ester (L-NAME). ACh relaxed posterior collecting veins at low concentrations but contracted them at higher concentrations; L-NAME enhanced the contractions but inhibited the relaxations, with the inhibition reversed by L-arginine. NADPH-diaphorase and eNOS were located predominantly in the posterior collecting veins. The fact that acetylcholine at low concentrations relaxes posterior collecting veins but contracts other collecting and outflow veins implies that the agonist in vivo may induce nasal congestion by increasing posterior blood volume. At higher concentrations, acetylcholine contracts posterior collecting veins as well, implying diminished blood volume in both venous systems, and consequently nasal decongestion. The induced contraction in posterior collecting veins is nitric oxide-independent, while the induced relaxation is nitric oxide-dependent.  相似文献   
97.
崩漏是月经周期、经期、经量严重失常的病证,是指经血非时暴下不止或淋漓不尽而言。调气活血汤为韩百灵氏治疗崩漏之经验方,韩氏认为本方证多由情志不遂,积思郁怒,或经产后,余血未尽,感寒涉水,过食生冷,不禁房事,余血停滞,瘀阻冲任,心血不得归经,而致崩中漏下。临证时须审因论治,若气病及血者,以活血为主,调气为辅。笔者自2005年以来,运用本方治疗妇女崩漏病34例,取得满意疗效,现报道如下。  相似文献   
98.
Immortalized cell lines offer significant logistical advantages over primary cells when used for in-vitro studies. Immortalized cells may, however, exhibit important differences relative to their primary cell counterparts. In this study, microarrays were used to make a genome-wide comparison between primary human umbilical vein endothelial cells (HUVECs) and EA.hy926, an immortalized HUVEC cell line, in their baseline properties and in their response to inhibition of the mevalonate pathway with an inhibitor of hydroxy methylglutaryl-coenzyme A reductase (statin). HUVECs and EA.hy926 were incubated with control medium, atorvastatin, mevalonate, or a combination of atorvastatin and mevalonate for 24 h. Gene expression profiles were obtained in duplicates using Affymetrix Human Genome U133A 2.0 arrays (Santa Clara, California, USA). Probe-sets were selected according to the following criteria: a twofold or greater increase/decrease in atorvastatin-treated cells compared with untreated cells; a twofold or greater reversal of the effect of atorvastatin by combined treatment with atorvastatin and mevalonate; no significant change in gene expression in cells treated with mevalonate alone compared with untreated cells. Most genes that were expressed by untreated HUVECs, were also expressed by untreated EA.hy926 cells. EA.hy926 cells, however, constitutively expressed a large number of additional genes, many of which were related to cell cycle control and apoptosis. Atorvastatin induced differential expression (> or = twofold) of 103 genes in HUVECs (10 up, 93 down) and 466 genes in EA.hy926 cells (198 up, 268 down). Applying the above selection criteria, thrombomodulin and tissue plasminogen activator were up-regulated in both cell types, whereas, connective tissue growth factor, thrombospondin-1, and cysteine-rich angiogenic inducer 61 were down-regulated. In conclusion, EA.hy926 cells retain most of the characteristics of endothelial cells under baseline conditions as well as after treatment with atorvastatin. It is necessary, however, to carefully select and validate changes in genes that are the focus of studies when using EA.hy926 cells. While this cell line is highly useful in studies on some genes, including genes encoding molecules involved in regulating thrombohemorrhagic homeostasis, they appear to be less suited for studies focused on other genes, particularly those involved in the regulation of cell proliferation and apoptosis.  相似文献   
99.
王涛  李秋军 《护理研究》2006,20(28):2567-2568
早期下床活动的必要性已得到大家认可,但术后早期病人常常较虚弱,且下床活动时会引发一些不适,病人也会有一些担心和顾虑,这在一定程度上会影响病人下床活动的积极性。颈椎手术本身有其特殊性,术后对颈部的稳定要求较高,因此此类病人活动有其特点。本研究以颈椎术后已下床活动的病人为研究对象,通过问卷调查,了解颈椎手术后病人首次下床的感受和相关需求,为进一步提高颈椎术后护理质量提供依据。1资料和方法1.1对象采用方便取样,选取2005年4月—2005年6月在某三甲医院因颈椎病入院、术后已下床活动的病人75例。其中男54例,女21例;年龄28岁~7…  相似文献   
100.
OBJECTIVE: To investigate the serial CT findings of Paragonimus westermani infected dogs and the microscopic structures of the worm cysts using Micro-CT. MATERIALS AND METHODS: This study was approved by the committee on animal research at our institution. Fifteen dogs infected with P. westermani underwent serial contrast-enhanced CT scans at pre-infection, after 10 days of infection, and monthly thereafter until six months for determining the radiologic-pathologic correlation. Three dogs (one dog each time) were sacrificed at 1, 3 and 6 months, respectively. After fixation of the lungs, both multi-detector CT and Micro-CT were performed for examining the worm cysts. RESULTS: The initial findings were pleural effusion and/or subpleural ground-glass opacities or linear opacities at day 10. At day 30, subpleural and peribronchial nodules appeared with hydropneumothorax and abdominal or chest wall air bubbles. Cavitary change and bronchial dilatation began to be seen on CT scan at day 30 and this was mostly seen together with mediastinal lymphadenopathy at day 60. Thereafter, subpleural ground-glass opacities and nodules with or without cavitary changes were persistently observed until day 180. After cavitary change of the nodules, the migratory features of the subpleural or peribronchial nodules were seen on all the serial CT scans. Micro-CT showed that the cyst wall contained dilated interconnected tubular structures, which had communications with the cavity and the adjacent distal bronchus. CONCLUSION: The CT findings of paragonimiasis depend on the migratory stage of the worms. The worm cyst can have numerous interconnected tubular channels within its own wall and these channels have connections with the cavity and the adjacent distal bronchus.  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