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   1507453篇
  免费   113248篇
  国内免费   6423篇
耳鼻咽喉   17841篇
儿科学   49354篇
妇产科学   39536篇
基础医学   199389篇
口腔科学   37899篇
临床医学   132356篇
内科学   308274篇
皮肤病学   32686篇
神经病学   126172篇
特种医学   64171篇
外国民族医学   274篇
外科学   238004篇
综合类   33810篇
现状与发展   2篇
一般理论   414篇
预防医学   123766篇
眼科学   30909篇
药学   102774篇
  5篇
中国医学   2855篇
肿瘤学   86633篇
  2018年   34037篇
  2017年   26940篇
  2016年   31184篇
  2015年   15260篇
  2014年   20860篇
  2013年   30668篇
  2012年   43055篇
  2011年   59090篇
  2010年   42282篇
  2009年   34923篇
  2008年   55089篇
  2007年   59542篇
  2006年   40653篇
  2005年   40734篇
  2004年   40142篇
  2003年   40087篇
  2002年   36321篇
  2001年   66322篇
  2000年   68305篇
  1999年   56763篇
  1998年   16937篇
  1997年   15220篇
  1996年   16097篇
  1995年   16330篇
  1994年   15197篇
  1993年   14206篇
  1992年   47129篇
  1991年   45825篇
  1990年   44087篇
  1989年   41886篇
  1988年   38805篇
  1987年   38119篇
  1986年   35875篇
  1985年   34661篇
  1984年   26376篇
  1983年   22127篇
  1982年   13872篇
  1981年   12449篇
  1980年   11759篇
  1979年   23549篇
  1978年   17082篇
  1977年   14389篇
  1976年   13191篇
  1975年   13729篇
  1974年   16111篇
  1973年   15398篇
  1972年   14173篇
  1971年   13037篇
  1970年   11897篇
  1969年   11122篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A human factors engineering analysis of a chemical containment laboratory was performed to develop appropriate standards for future laboratory design. In order to perform this evaluation, a state-of-the-art facility was studied in depth. Measurements and observations were made of key operating areas. In addition, technicians were observed and interviewed as they performed various tasks. Compiled data were compared to existing ergonomic standards. The occupational implications of instituting ergonomically developed laboratory design standards are as follows: increased worker health, safety and productivity, improved work quality and reduced stress.  相似文献   
992.
This paper provides a comprehensive methodological review of the literature assessing the relationship between marital satisfaction and communication. The investigations vary greatly in the adequacy of their assessment measures and soundness of their research design. Although it is generally concluded that both content and process communication are related to marital satisfaction, replication of the better designs is necessary. Specific findings and their practical implications for both future research and marital therapy are discussed.  相似文献   
993.
Intrathecal morphine for post-thoracotomy pain   总被引:1,自引:0,他引:1  
We wished to investigate possible differences in the duration of postoperative analgesia and the incidence of respiratory depression after the intrathecal injection in the lumbar area of 10 micrograms/kg morphine in hypobaric and hyperbaric solution for relief of post-thoracotomy pain. Twenty-nine patients received morphine plus dextrose (hyperbaric) and 21 received morphine in preservative-free normal saline. The duration of analgesia was longer with the morphine in the normal saline group than in the hyperbaric group (P less than 0.04). One patient developed delayed respiratory depression. Our data support the use of morphine in normal saline mixtures for greater duration of analgesia after thoracic operations.  相似文献   
994.
S E Bedell  D Pelle  P L Maher  P D Cleary 《JAMA》1986,256(2):233-237
We studied compliance with do-not-resuscitate (DNR) orders at a university hospital where a DNR protocol has existed since 1979. Documentation of DNR status in patient progress notes and chart orders increased through 1983. During a 12-month period (March 1983 through April 1984), we studied in detail the medical records of 521 patients who had a cardiopulmonary arrest in the hospital. Seventy-five percent (389 of 521) of these patients were designated DNR. Patients who were designated DNR were significantly more likely to be older, to have malignancy or an abnormal mental status, and to be less likely to have acute myocardial infarction, stroke, or chronic obstructive pulmonary disease than patients in whom resuscitation was attempted. Eighty-six percent of families, but only 22% of patients, were involved in the decision to designate a patient DNR. The decision to designate a patient DNR occurred late in the course of a patient's illness, often when the patient was in coma. For 28% of patients, some form of medical care was withdrawn or withheld after they were designated DNR. These data suggest that use of the DNR protocol requires changes if patients are to participate in the decision not to undergo cardiopulmonary resuscitation.  相似文献   
995.
Since the aminoglycoside antibiotic apramycin was licensed for veterinary use in 1980, all isolates of Escherichia coli and salmonellas received at the Central Veterinary Laboratory have been monitored for resistance to apramycin and the related antibiotic gentamicin. During the period 1982-4, the incidence of resistance in E. coli to apramycin increased from 0.6% in 1982 to 2.6% in 1984. In salmonellas the incidence of resistance to apramycin increased from 0.1% in 1982 to 1.4% in 1984. Resistance to both apramycin and gentamicin was detected in six different salmonella serotypes, although an isolate of Salmonella thompson from poultry was resistant to gentamicin but not apramycin. Most of the cultures were isolated from pigs, although the incidence of apramycin resistance in S. typhimurium (DT 204C) from calves has shown a recent dramatic increase. All the isolates with one exception produced the enzyme aminoglycoside 3-N-acetyltransferase IV (ACC(3)IV). The resistance was transferable by conjugation in most of the strains examined, and the plasmids specifying the resistance have been found to belong to a number of different incompatibility groups. Plasmids from three E. coli strains were compatible with all the reference plasmids and belonged to a previously undescribed group which was investigated further. It is suggested that bacteria from humans should be examined for resistance to apramycin and gentamicin to determine the possibility of the antibiotic-resistance bacteria, and their genes, spreading from animals to humans.  相似文献   
996.
997.
Button wiring has been used as an alternative to eyelet wiring in the Department of Oral and Dental Surgery of Birmingham General Hospital since 1977. This clinical update reviews 65 patients with mandibular fractures in which button wires were utilised in their treatment.  相似文献   
998.
Incestuous child sexual abuse has received increasing attention recently, but relatively little attention has focused on the multigenerational dimensions of this problem. The case presented places incest into a multigenerational context and demonstrates how quickly family relationships may become eroticized in an uncommon form: between sisters.  相似文献   
999.
Atomic absorption spectrometry and x-ray fluorescence have been used to determine the lead content of metatarsal and tibia bone samples. For a range of bone lead levels from 6.5 to 83 micrograms g-1 of ashed bone there is no evidence of a systematic difference between the two techniques of more than 1 microgram g-1. There is, however, some evidence that random differences between the two in vitro analyses applied to the same bone sample are larger than can be accounted for by known measurement uncertainties. Variations in bone composition could account for these differences. Because the x-ray fluorescence technique is applied in an identical way to in vivo analysis, it is concluded that the uncertainties in in vivo measurements are small.  相似文献   
1000.
A survey of research activity of American academic child psychiatrists was completed in February, 1989. The survey demonstrated an increase in research activity since the 1983 report in the Current Status of Child Psychiatry. A definition of a researcher was derived from a study of internists and general psychiatrists and applied to the 488 respondents (78.5% of sample), and it was found that males outnumber females and that researchers contribute significantly more to the literature and education than nonresearchers. Early research exposure and mentoring are important influences on a research career. Recommendations by researchers for future training of researchers are presented. Periodic surveys are encouraged.  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