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   15198篇
  免费   1199篇
  国内免费   108篇
耳鼻咽喉   170篇
儿科学   531篇
妇产科学   300篇
基础医学   2388篇
口腔科学   366篇
临床医学   1588篇
内科学   3226篇
皮肤病学   267篇
神经病学   1082篇
特种医学   747篇
外国民族医学   1篇
外科学   2007篇
综合类   116篇
一般理论   8篇
预防医学   1161篇
眼科学   325篇
药学   1226篇
中国医学   14篇
肿瘤学   982篇
  2022年   115篇
  2021年   225篇
  2020年   195篇
  2019年   245篇
  2018年   276篇
  2017年   269篇
  2016年   315篇
  2015年   285篇
  2014年   408篇
  2013年   546篇
  2012年   710篇
  2011年   661篇
  2010年   410篇
  2009年   401篇
  2008年   577篇
  2007年   664篇
  2006年   553篇
  2005年   551篇
  2004年   611篇
  2003年   507篇
  2002年   490篇
  2001年   435篇
  2000年   473篇
  1999年   424篇
  1998年   247篇
  1997年   212篇
  1996年   208篇
  1995年   203篇
  1994年   174篇
  1993年   169篇
  1992年   320篇
  1991年   351篇
  1990年   342篇
  1989年   373篇
  1988年   294篇
  1987年   298篇
  1986年   262篇
  1985年   331篇
  1984年   209篇
  1983年   175篇
  1982年   151篇
  1981年   115篇
  1980年   113篇
  1979年   169篇
  1978年   126篇
  1977年   120篇
  1976年   97篇
  1975年   106篇
  1974年   117篇
  1973年   105篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs.  相似文献   
42.
OBJECTIVE: A new class of carboxylic acids has tumoricidal activity for head and neck squamous cell cancer (HNSCC). Fusaric acid (FA) can chelate divalent cations, especially zinc, and inactivate zinc finger proteins involved in DNA repair and protein synthesis. METHODS: 2 squamous carcinoma lines were utilized for in vitro and in vivo portions of this study. Cell counting and flow cytometry were used to analyze cells in culture in treatment and control groups over 96 hours. HNSCC subcutaneous implants were created in treatment and control groups of BALB-c nude mice (N = 30). RESULTS: In vitro studies demonstrated significant changes in cell numbers and cell cycle. In vivo studies of daily intralesional therapy for 1 month also showed reduced onset of growth and overall growth compared to controls. CONCLUSION: FA appears to have a tumoristatic/tumoricidal effect on HNSCC. Further nude mice studies are needed to optimize dosing and administration regimens for FA in anticipation of clinical trials.  相似文献   
43.
OBJECTIVE: To assess the extent of nosocomial transmission of tuberculosis among infants, family members, and healthcare workers (HCWs) who were exposed to a 29-week-old premature infant with congenital tuberculosis, diagnosed at 102 days of age. DESIGN: A prospective exposure investigation using tuberculin skin test (IST conversion was conducted. Contacts underwent two skin tests 10 to 12 weeks apart. Clinical examination and chest radiographs were performed to rule out disease. Isoniazid prophylaxis was administered to exposed infants at higher risk. SETTING: A neonatal intensive care unit in an urban hospital in Brussels, Belgium. PARTICIPANTS: Ninety-seven infants, 139 HCWs, and 180 visitors. RESULTS: Newly positive TST results occurred in HCWs who had been in close contact with the infant. Six (19%) of 32 primary care nurses and physicians had TST conversions and received treatment. Among the 97 exposed infants, 85 were screened and 34 were identified as at higher risk of infection. Of these, 27 received preventive isoniazid. None of the infants and none of the 93 other infants' family members evaluated were infected. CONCLUSIONS: Congenital tuberculosis in an infant poses a risk for nosocomial transmission to HCWs. Delayed diagnosis of this rare disease and close proximity are the most important factors related to transmission.  相似文献   
44.
45.
46.
Introduction - Interobserver variation among four observers in evaluation of eight selected neurological signs was investigated. Material & methods - Two hundred and two consecutive unselected inpatients were examined by two senior neurologists and two trainees, all without knowledge of the neurological case history. The signs examined were: anisocoria, jerky eye movements, facial palsy, elbow extension force, finger-nose test, Barré sign, knee jerk, and extensor plantar reflex. Observed agreement rates and kappa coefficients were calculated in order to compare the interobserver variability among neurologists and trainees, and to evaluate differences in the interobserver variability between signs. Results - Observed agreement rates varied from 0.80 to 0.95 for neurologists and from 0.65 to 0.98 for trainees. For neurologists kappa coefficients ranged from 0.40 to 0.67 and for trainees from 0.22 to 0.81. The neurologists had higher kappa values than the trainees in 5 signs, but this difference was only statistically significant for jerky eye movements. For the individual signs the observed agreement rates were between 0.50 and 0.93 for all four examiners combined, and overall kappa values varied from 0.32 to 0.71 with highest agreement for facial palsy and lowest for knee jerk. Conclusion - The magnitude of the interobserver and intersign variation indicates that the interpretation of the neurological signs tested, without knowledge of the case history, should be done with some caution.  相似文献   
47.
We report here the complete amino acid sequence of another member of the type beta transforming growth factor gene family, deduced from the nucleotide sequence of three overlapping cDNA clones. The C-terminal 112 amino acids share approximately 80% sequence identity with type beta 1 and beta 2 transforming growth factors, with many of the remaining differences being conservative substitutions. By analogy to type beta 1 and type beta 2 transforming growth factors, we predict the protein to be synthesized as a 412 amino acid precursor that undergoes proteolytic cleavage to produce the mature polypeptide.  相似文献   
48.
Muscle fiber typing and in vitro contracture tests were performed in 59 patients investigated for susceptibility to malignant hyperthermia (MH). Eighteen patients were found to be susceptible to MH. There was no difference in age or fiber type distribution between MH susceptible and non-susceptible patients. No correlation was found between age and fiber type distribution. Separate analyses for each diagnostic group revealed no relationship between age or fiber type distribution and response to halothane or caffeine. When all caffeine results were pooled, however, there was a significant effect of age on the caffeine specific concentration (the concentration eliciting a contracture of 1 g), but not on the caffeine threshold concentration (the minimal concentration eliciting an increase in tension). It is concluded that age and fiber type distribution have no influence on MH diagnosis, if the protocol of the European MH Group for evaluation of susceptibility to MH is followed.  相似文献   
49.
A monoclonal antibody has been raised against a surface membrane antigen present on leukemic myeloblasts. In 52 consecutive patients with acute myeloid leukemia treated in a standardized fashion with intensive chemotherapy the immunologic subclass with respect to this antigen was correlated to the clinical outcome. We found the expression of this antigen to predict a poor prognosis, when measured as survival of CR-patients and as survival after 1st relapse.  相似文献   
50.
Congenital hypoplasia of the adrenal glands (CHA) is a rare condition, particularly in the absence of a central nervous system (CNS) anomaly. Two major types of CHA have been described in the setting of an apparently normal CNS and pituitary: a cytomegalic type usually with X-linked recessive inheritance and a miniature adult type that, when hereditary, is an autosomal recessive trait. Glycerol kinase deficiency (GKD) is an X-linked recessive trait, and it may be associated with CHA and adrenal insufficiency, presumably because of deletion of adjacent X-linked loci. We report on three sibling infants, one male and two females, with normal CNS and lethal CHA of the miniature adult type, selective absence of pituitary LH; two of the infants also had glycerol kinase (GK) activity that was decreased but not in the GKD range. Restriction fragment length polymorphism (RFLP) analysis of X chromosome markers located at Xp21-p22 was carried out on the maternal grandfather, both parents, two of three affected infants, and a living normal brother. The results excluded the X-linked type of this disorder associated with GKD in this family. Autosomal recessive inheritance is most likely.  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