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   19750篇
  免费   1256篇
  国内免费   54篇
耳鼻咽喉   351篇
儿科学   546篇
妇产科学   324篇
基础医学   2868篇
口腔科学   546篇
临床医学   1623篇
内科学   3926篇
皮肤病学   487篇
神经病学   1903篇
特种医学   1102篇
外国民族医学   10篇
外科学   2889篇
综合类   133篇
一般理论   4篇
预防医学   1282篇
眼科学   349篇
药学   1345篇
中国医学   24篇
肿瘤学   1348篇
  2022年   137篇
  2021年   335篇
  2020年   220篇
  2019年   305篇
  2018年   352篇
  2017年   286篇
  2016年   390篇
  2015年   423篇
  2014年   518篇
  2013年   608篇
  2012年   1008篇
  2011年   1038篇
  2010年   574篇
  2009年   589篇
  2008年   1004篇
  2007年   977篇
  2006年   981篇
  2005年   969篇
  2004年   944篇
  2003年   896篇
  2002年   844篇
  2001年   631篇
  2000年   625篇
  1999年   556篇
  1998年   250篇
  1997年   203篇
  1996年   184篇
  1995年   152篇
  1994年   154篇
  1993年   144篇
  1992年   339篇
  1991年   312篇
  1990年   326篇
  1989年   301篇
  1988年   265篇
  1987年   249篇
  1986年   235篇
  1985年   226篇
  1984年   193篇
  1983年   159篇
  1982年   108篇
  1981年   91篇
  1979年   156篇
  1978年   116篇
  1977年   91篇
  1975年   109篇
  1974年   105篇
  1973年   100篇
  1970年   96篇
  1969年   95篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
Treatment of severe craniocerebral traumas in medium and major hospitals not provided with special neurosurgical equipment requires particularly close interdisciplinary cooperation between surgeons, neurologists and anaesthesiologists. CT facilities are an essential prerequisite for best possible patient care. Patient safety during the posttraumatic and postoperative phases is improved by measuring the intracranial pressure. Whereas corticosteroid treatment may be arguable, barbiturate treatment should presently not be a routine procedure because of its side effects and high rate of complications.  相似文献   
74.
The variability in plasma and urine equine procaine measurement between three independent laboratories using current methods led to the development of a sensitive, reliable, and reproducible high-performance liquid chromatographic method. Standardbred mares were administered either a penicillin G procaine preparation intramuscularly or procaine hydrochloride subcutaneously, and blood and urine were collected at defined time intervals. By HPLC the detection limits for procaine in plasma and urine were 1 and 10 ng/mL, respectively. In contrast procaine in plasma could not be detected by GC-NPD, while the urinary detection limit was 50 ng/mL. The concentration of fluoride in the collection tubes and repetitive freeze-thawing modified plasma procaine measurement. Urinary pH was a factor in estimation of urine procaine levels with greater recovery and reproducibility of results at pH 5 as compared to pH 7. This HPLC method provides a simple, sensitive, and reliable quantitation of procaine in equine plasma and urine.  相似文献   
75.
Over the past 10 years, much fascinating information has been obtained concerning the biochemistry, genetics, toxicological implications and molecular genetics of the N-acetylation polymorphism in mice. Using C57BL/6J (B6) mice as representative of rapid acetylation and A/J (A) mice as representing slow acetylation, it has been shown that the polymorphism observed in N-acetyltransferase (NAT) activity in liver also occurs in kidney, bladder, blood, and other tissues. The development of congenic acetylator mouse lines derived from B6 and A, have provided the necessary tools to study the role of the acetylation polymorphism, on either the B6 or A genetic background, free of nearly all other genetic differences between these strains. Eliminating genes which modify and complicate the differences due to the acetylator genes make the congenic lines very useful in toxicology studies, particularly those involving carcinogenesis. The molecular genetic basis of the acetylator polymorphism in B6 and A mice involves two Nat genes. Nat-1 encodes a protein termed NAT1 which is identical in rapid and slow acetylator strains. Nat-2, however, differs between rapid and slow strains by a single nucleotide change in the coding region. The corresponding NAT2 proteins differ by a single change at amino acid 99: an hydrophilic asparagine in rapid acetylator NAT2 to an hydrophobic isoleucine in NAT2 from slow acetylators. The mechanistic basis for the differences between rapid and slow acetylation in mice appears to be that NAT2 from the rapid B6 strain is 15-fold more stable at 37 degrees C and is transcribed/translated with a maximal efficiency twice that of the enzyme from slow acetylator A mice. Results discussed in this review indicate that mice provide an excellent system for studying the N-acetyltransferase polymorphism and also are useful for modelling several aspects of the human N-acetyltransferase polymorphism.  相似文献   
76.
  相似文献   
77.
OBJECTIVES: To compare the efficacy of structured questionnaire screening and prenatal urine toxicology for the detection of substance use by pregnant women, and to describe substance use patterns in a group of women presenting to a university-based obstetric clinic. METHODS: All patients presenting to our obstetric clinic for their first prenatal visit were evaluated for evidence of current use of alcohol or any illicit substances. Nursing personnel administered an extensive questionnaire, which included detailed questions about past and current substance use patterns. Urine samples were examined by a commercial laboratory for alcohol and a number of illicit substances. Current users were defined as those who admitted use within the past 30 days or who had positive urine toxicology. RESULTS: Fifty-eight of 302 patients (19.2%) were identified as current users of alcohol or illicit substances. Only 17 of 41 women (41.5%) with toxicologic evidence of recent use admitted to current use. Only 17 of 34 (50.0%) admitting to current use had toxicology positive for any substance. Patients with a history of multiple past substance use were significantly more likely to have positive urine toxicology than those without such a history (26.1 versus 7.4%; P < .005). Among current users, multiple substance use (34.5%) and cigarette smoking (52%) were common. CONCLUSION: A screening combination of structured questionnaire and universal urine toxicology identifies more current users than either technique alone, and neither is clearly superior to the other. A history of multiple substance use may be an important indicator of current use.  相似文献   
78.
79.
Body packing is a well recognized method of drug trafficking by smuggling drug containers in the gastrointestinal tract. Medical professionals might get involved with body packers after presentation by law enforcement or in case of medical emergencies such as drug overdose or mechanical intestinal obstruction due to the containers within the gastrointestinal tract. Besides the medical aspects in treating these patients, physicians must be aware of all the different legal specifics in dealing with body packers. In case of medical emergencies, drug traffickers have the legal status of regular patients with respect to professional medical discretion. The question remains of what physicians should do with the drugs after surgical removal? Even though the body packer remains the legal owner of the drugs, physicians may not return the drugs, since that constitutes the criminal offence of dealing in narcotics. Returning the drugs to law enforcement authorities is also prohibited because of professional medical discretion. The only way out of this predicament is for physicians to destroy the drugs under the observation of witnesses.  相似文献   
80.
Childhood psoriasis is a disease with manifold clinical presentations which can make the correct diagnosis sometimes difficult. In a female infant, slightly itching, erythematous papules and plaques with discrete scaling spread over large parts of the integument starting from age three months. Histological examination supported the diagnosis of exanthematous infantile psoriasis. Topical treatment with dithranol in petrolatum led to slow clearance of the skin lesions.  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