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   331624篇
  免费   30060篇
  国内免费   23338篇
耳鼻咽喉   3045篇
儿科学   3542篇
妇产科学   4978篇
基础医学   40558篇
口腔科学   5669篇
临床医学   46342篇
内科学   50475篇
皮肤病学   3131篇
神经病学   18573篇
特种医学   12321篇
外国民族医学   214篇
外科学   33745篇
综合类   51598篇
现状与发展   81篇
一般理论   20篇
预防医学   20410篇
眼科学   9730篇
药学   33690篇
  360篇
中国医学   18219篇
肿瘤学   28321篇
  2024年   1070篇
  2023年   5195篇
  2022年   13551篇
  2021年   17024篇
  2020年   12527篇
  2019年   11203篇
  2018年   11707篇
  2017年   10256篇
  2016年   9621篇
  2015年   14741篇
  2014年   18311篇
  2013年   15811篇
  2012年   23484篇
  2011年   26494篇
  2010年   16460篇
  2009年   12712篇
  2008年   17424篇
  2007年   17394篇
  2006年   17360篇
  2005年   17004篇
  2004年   10820篇
  2003年   9915篇
  2002年   8557篇
  2001年   7556篇
  2000年   8340篇
  1999年   9051篇
  1998年   5498篇
  1997年   5514篇
  1996年   4339篇
  1995年   3929篇
  1994年   3217篇
  1993年   2100篇
  1992年   2827篇
  1991年   2415篇
  1990年   2118篇
  1989年   1863篇
  1988年   1563篇
  1987年   1355篇
  1986年   1107篇
  1985年   912篇
  1984年   526篇
  1983年   373篇
  1982年   242篇
  1981年   238篇
  1980年   188篇
  1979年   221篇
  1978年   82篇
  1977年   89篇
  1974年   102篇
  1973年   83篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
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   
102.
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   
103.
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   
104.
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   
105.
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   
106.
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   
107.
王欣 《辽宁医学杂志》2004,18(3):125-127
抗菌药物的开发与应用使临床成功防治感染性疾病成为可能 ,使严重感染的预后大为改观。但抗菌药物的应用同时也可引起很多不良反应 ,甚至致残或致死。抗菌药物的不良反应主要包括毒性反应、变态反应、二重感染。1 毒性反应指药物引起的生理、生化等功能异常和 (或 )组织、器官  相似文献   
108.
Urethral reconstruction with graft substances, such as skin and bladder mucosa, has been previously used when primary anastomosis cannot be achieved. However, stricture and meatal prolapse are associated with these grafts. We report the use of buccal mucosa for the reconstruction of urethral defects in 3 patients. One patient with failed operation for hypospadias received tube buccal mucosal graft for urethral replacement. Two patients with urethral necrosis and stricture received onlay buccal mucosal graft. All patients were disease-free during follow-up (range, 12 to 49 months; mean, 36 months). One patient had a pinhole fistula that was successfully managed with simple repair. This technique appears to be useful for urethral reconstruction when a local graft is not available, even in patients with complicated conditions.  相似文献   
109.
咳喘"冬病夏治"临床应用   总被引:2,自引:0,他引:2  
王文琴 《光明中医》2006,21(5):F0003-F0003
"冬病夏治"法意即冬天易发作的病,在夏天(特指伏天)提前预防性治疗的一种特色疗法.寒性咳喘是我国北方冬季的常见病、多发病.我院针灸科从1983年开始,每年伏天运用针药并用外敷治疗寒性咳喘的"冬病夏治"法,治愈数千例患者,取得了很好的疗效.  相似文献   
110.
Atraumetic Restorative Treatment (ART) has been adopted around the world to avoid unnecessary extractions, especially in non-industrialized countries The development of specific glass ionomer cements marketed for the ART technique has contributed to the technical success rate. In this study. Ketac-Molara (3M ESPE. Dental Medzn Germany) was used to restore 150 Class I cavities in 118 Brazilian public school children, aged from 7–12 years. At baseline and at subsequent recalls. CPI probes with a ball-end of 0.5 millimeters (mm) were used to assess loss of restorative material, and photographic color transparencies of restorations were made. After six months. 83 patients returned for follow-up examinations, with 71.8% of their restorations designated as acceptable. After three years. 49 patients with 57 ART-restorations were evaluated, with 21.0% of these restorations graded as acceptable Another 29.8% of their restorations had been replaced by more permanent materials. The main objective of the ART technique is tooth retention; this was achieved for 94.7% of the restored teeth in a high caries risk population who returned for recalls.  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