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   25552篇
  免费   1837篇
  国内免费   716篇
耳鼻咽喉   271篇
儿科学   398篇
妇产科学   393篇
基础医学   2318篇
口腔科学   1269篇
临床医学   3369篇
内科学   2664篇
皮肤病学   607篇
神经病学   1443篇
特种医学   1058篇
外国民族医学   5篇
外科学   3973篇
综合类   3555篇
现状与发展   1篇
一般理论   1篇
预防医学   2335篇
眼科学   313篇
药学   1907篇
  23篇
中国医学   1228篇
肿瘤学   974篇
  2024年   61篇
  2023年   414篇
  2022年   733篇
  2021年   1040篇
  2020年   964篇
  2019年   862篇
  2018年   812篇
  2017年   842篇
  2016年   915篇
  2015年   845篇
  2014年   1632篇
  2013年   1750篇
  2012年   1300篇
  2011年   1629篇
  2010年   1405篇
  2009年   1149篇
  2008年   1173篇
  2007年   1210篇
  2006年   1057篇
  2005年   945篇
  2004年   780篇
  2003年   702篇
  2002年   543篇
  2001年   463篇
  2000年   452篇
  1999年   404篇
  1998年   346篇
  1997年   353篇
  1996年   295篇
  1995年   318篇
  1994年   295篇
  1993年   245篇
  1992年   220篇
  1991年   237篇
  1990年   202篇
  1989年   164篇
  1988年   162篇
  1987年   142篇
  1986年   129篇
  1985年   154篇
  1984年   135篇
  1983年   96篇
  1982年   133篇
  1981年   68篇
  1980年   86篇
  1979年   52篇
  1978年   46篇
  1977年   37篇
  1976年   35篇
  1974年   20篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
51.
Guidelines for design of clinical trials evaluating behavioral headache treatments were developed to facilitate production of quality research evaluating behavioral therapies for management of primary headache disorders. These guidelines were produced by a Workgroup of headache researchers under auspices of the American Headache Society. The guidelines are complementary to and modeled after guidelines for pharmacological trials published by the International Headache Society, but they address methodologic considerations unique to behavioral and other nonpharmacological treatments. Explicit guidelines for evaluating behavioral headache therapies are needed as the optimal methodology for behavioral (and other nonpharmacologic) trials necessarily differs from the preferred methodology for drug trials. In addition, trials comparing and integrating drug and behavioral therapies present methodological challenges not addressed by guidelines for pharmacologic research. These guidelines address patient selection, trial design for behavioral treatments and for comparisons across multiple treatment modalities (eg, behavioral vs pharmacologic), evaluation of results, and research ethics. Although developed specifically for behavioral therapies, the guidelines may apply to the design of clinical trials evaluating many forms of nonpharmacologic therapies for headache.  相似文献   
52.
P1 blood group positivity has been postulated as a host factor which may provide protection against the development of post-enteropathic hemolytic uremic syndrome (HUS). In this study, blood group status in 20 Inuit survivors ofEscherichia coli 0157: H7-associated HUS was compared with age-and sex-matched controls from the same community who had experienced uncomplicated diarrheal illness due to the same pathogen. Of 20 HUS survivors, 6 were P1 antigen positive compared with 8 of the 20 controls (P=0.7). We conclude that P1 antigen positivity was not protective against HUS in this population. Further studies of this condition to clarify the role of host factors in verotoxin-induced endothelial damage are indicated.  相似文献   
53.
应用双光子及单光子吸收测定技术,检测了92名出生3d内的新生儿骨矿质含量,其中巨大儿30名,正常体重儿32名,低出生体重儿30名,其孕龄分别是40.1±0.7、39.1±1.5和37.4±1.2孕周。结果表明,巨大儿、正常体重儿、低出生体重儿的全身骨矿质含量分别是101.6±28.8、85.2±19.8、59.9±27.2g/cm2,巨大儿骨矿质含量最高,正常体重儿次之,低出生体重儿最低,差异有显著性(P<0.01)。颅骨、肱骨、股骨的骨矿质含量与全身的骨矿质含量有高度的相关性,相关系数分别是0.943、0.879和0.745(P<0.01)。全身的骨矿质含量与出生体重、孕龄及头围有高度相关性,相关系数分别是0.755、0.596和0.556(P<0.01)。提示颅骨、肱骨及股骨的任一部位均可代表全身的骨矿质含量,肱骨是确定全身骨矿质含量较好的部位,新生儿骨矿质含量受出生体重、孕龄及头围的影响较大。  相似文献   
54.
Rh血型不合新生儿溶血病检测方法及应用   总被引:3,自引:0,他引:3  
产前检测Rh,D因子及抗人球蛋白(coombs)试验是必要的。测定Rh,D因子及抗D滴度使用木瓜酶方法。通过对11261例孕妇常规检查Rh,D因子,发现D阴性74例。Rh,D阴性妇女占6.5‰。22例Rh,D阴性的孕妇所分娩的新生儿均为Rh,D阳性。其中2例孕妇血清抗D滴度为1∶32,病情严重,宫内输血无效,胎死宫内。初产妇13例,占59%。活产20例,存活率90%。Rh因子及抗人球蛋白试验方法简便、易行,一般医院均可进行。对有流产史、输血史的孕妇检查Rh因子是十分必要的。在有条件的医院,对Rh,D阴性的产妇分娩Rh,D阳性的新生儿之后,产妇应预防性注射抗D免疫球蛋白  相似文献   
55.
A critical commentary and updating of the guinea pig maximization test   总被引:4,自引:3,他引:1  
The guinea pig maximization test (GPMT) of Magnusson and Kligman was published in 1969. Since then, a vast body of practical experience with the test has been accumulated. New information requires that certain aspects of the procedure be reevaluated, especially with regard to the interpretation of challenge results. In particular, awareness of the phenomenon of hyperirritable skin (the 'angry back' phenomenon) suggests that presently used controls are not always adequate and may overstate allergenicity owing to false-positive reactions. The control group should be exposed to a chemical insult at induction which provokes an inflammatory reaction comparable to the test substance. We present strategies to distinguish irritant from allergic responses. Allergic reactions should persist on rechallenge weeks later, while nonspecific irritant reactions generally fade and are irreproducible in particular animals. Finally, when a chemical is identified as a contact sensitizer of risk is necessary to estimate the relevance of the test result to usage in the real world.  相似文献   
56.
本文应用改良的血浆凝块技术和共培养系统研究特发性血小板减少性紫癜(ITP)患者T细胞在体外对异体骨髓巨核细胞生成作用的影响,以探讨ITP的发病机制。实验结果表明,从总体来看,ITP患者的T细胞当加到培养物中和靶细胞共培养时,对巨核系祖细胞集落形成单位(CFU-MK)的集落效应无明显的影响。其中三例PAIgG升高患者的T细胞对CFU-MK有不同程度的抑制作用。以上结果提示ITP的发病机制相当复杂。除体液免疫机制外,也有细胞免疫机制参与,T细胞或其亚群对巨核系祖细胞生成抑制在ITP的发病机制中可能起着一定的作用。  相似文献   
57.
Conclusion Reviewing the history of diagnostic procedures of causative organisms of respiratory infections, invasive techniques such as the protected specimen catheter (PSB) and bronchoalveolar lavage (BAL) have become the preferred choices because they have many advantages. These methods cause the patient relatively little discomfort, and permit an early diagnosis since they can easily be performed at the bedside and the causative organism from the disease site is obtained in cultures. These procedures can be used not only in patients with community-acquired lung infections, but also in immunocompromised hosts, including those with blood diseases or following renal transplantation, in patients in intensive care units and in mechanically-ventilated patients so that the cause can be accurately determined and chemotherapy started quickly, resulting in better therapeutic efficacy. Although these invasive procedures are advantageous for the diagnosis of respiratory infections, they also present various problems which remain to be addressed including minimizing contamination and setting diagnostic threshold values. However, the importance of accurately determining the causative organism in respiratory infections should be recognized as the most important factor, and these methods have shown to date to provide the most accurate information to aid in the timely treatment of respiratory infections in a wide variety of patients.  相似文献   
58.
目的探讨肿胀技术在体表外科手术中的应用价值。方法随机选择体表肿物与先天性畸形、体表瘢痕、乳房整形、脂肪抽吸、腹壁整形、除皱、隆胸、褥疮、面瘫及颅骨电烧伤等230例体表外科手术应用肿胀技术,成人164例,完全采用肿胀法局麻技术,儿童66例,在全麻下应用肿胀技术。并与相应手术非肿胀法下施行进行了比较。结果脂肪抽吸术中利多卡因用量可达30~60mg/kg体重。肿胀技术具有易于进行解剖间隙的分离、减少术中失血、增强麻醉效果、增加手术安全性和术后恢复快等优点。结论肿胀技术可推广到体表外科手术中广泛应用,对儿童更为适宜,对减少输血造成的疾病具有重要意义。  相似文献   
59.
足组织缺损的显微修复   总被引:15,自引:11,他引:4  
1984年~1994年共收治各种足部组织创伤缺损236例,均采用显微外科技术进行组织移植修复,其中单纯皮瓣移植修复187例,复合皮瓣移植修复49例。吻合血管游离移植修复97例,带血管蒂移位修复139例。4例前足缺损者用带肩胛骨的复合皮瓣移植修复,6例足跟严重缺损者用带血管的腓骨复合皮瓣移植修复。经1~10年随访,皮瓣、复合皮瓣、移植或再植的骨骨各全部成活,愈合良好,足功能基本得到恢复,可行走、负重,186例恢复了原工作。认为,恢复足部结构完整与重建足跟、足底的感觉是获得良好功能的关键  相似文献   
60.
Low-income minority patients from East St. Louis, Illinois, a depressed midwestern urban city, who had visited acute care settings with asthma symptoms, participated in a focus group. Questions were constructed around the Health Belief Model to characterize participants' experiences in receiving asthma care, their confidence in long-term asthma self-management, barriers they perceived to managing their asthma, and recommendations they would make for improving asthma care in their community. Analysis of comments suggests an appreciable understanding of asthma triggers, limited coping behaviors for asthma symptoms, very limited practice of active asthma management, perception of the health care system as frequently insensitive to their needs or their knowledge of their own care, exchange of well-articulated information regarding how to deal with the system, and an apparent lack of awareness of any potential contribution of patient education or support system.  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