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   62857篇
  免费   5324篇
  国内免费   146篇
耳鼻咽喉   550篇
儿科学   2251篇
妇产科学   1521篇
基础医学   8194篇
口腔科学   1193篇
临床医学   7851篇
内科学   12262篇
皮肤病学   1288篇
神经病学   6310篇
特种医学   1665篇
外科学   7199篇
综合类   799篇
现状与发展   1篇
一般理论   98篇
预防医学   7818篇
眼科学   940篇
药学   4461篇
中国医学   58篇
肿瘤学   3868篇
  2023年   710篇
  2022年   1121篇
  2021年   2290篇
  2020年   1350篇
  2019年   2002篇
  2018年   2234篇
  2017年   1528篇
  2016年   1755篇
  2015年   1861篇
  2014年   2459篇
  2013年   3257篇
  2012年   4657篇
  2011年   4530篇
  2010年   2322篇
  2009年   2035篇
  2008年   3288篇
  2007年   3384篇
  2006年   3049篇
  2005年   2901篇
  2004年   2569篇
  2003年   2249篇
  2002年   2120篇
  2001年   1118篇
  2000年   1108篇
  1999年   1015篇
  1998年   526篇
  1997年   388篇
  1996年   349篇
  1995年   363篇
  1994年   305篇
  1993年   301篇
  1992年   660篇
  1991年   673篇
  1990年   623篇
  1989年   544篇
  1988年   508篇
  1987年   501篇
  1986年   502篇
  1985年   501篇
  1984年   369篇
  1983年   317篇
  1982年   242篇
  1981年   231篇
  1980年   184篇
  1979年   341篇
  1978年   253篇
  1977年   211篇
  1974年   222篇
  1973年   209篇
  1971年   199篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Our objective was to determine the inter-examiner agreement of a simplified pelvic organ prolapse quantification (POPQ) exam and to assess its correlation with the standard POPQ exam. This study consists of two parts; both were preformed in a prospective, randomized, blinded fashion on women presenting with complaints attributed to pelvic organ support defects. The first study was done to determine the inter-examiner reliability of a simplified POPQ exam. The simplified POPQ exam is based on the POPQ with similar ordinal staging but with only four points measured instead of nine. Forty-eight women underwent exams by five different investigators. The order of exams was randomized and the examiners were blinded to the results of each other’s findings. The results of these two exams were compared using weighted kappa statistics. The second part of the study was done to determine the inter-system agreement between the simplified vs standard POPQ exam. A group of 49 women were examined by four different investigators: one using the simplified and the other using standard POPQ exams. The order of the exams was randomized and the examiners were blinded to the results of each other’s exam. Kendall’s tau-b statistics were used to determine the inter-system agreement. For the inter-examiner reliability of the POPQ exam, the average age was 60±13 years. The weighted kappa statistics for the inter-examiner reliability of the simplified prolapse classification system were 0.86 for the overall stage, 0.89 and 0.86 for the anterior and posterior vaginal walls, respectively, 0.82 for the apex/cuff, and 0.72 for the cervix. All demonstrate significant agreement. For the inter-system association between the simplified POPQ and standard POPQ, the average age was 61±15 year. The Kendall’s tau-b value for overall stage was 0.90, 0.83, and 0.87 for the anterior and posterior walls respectively, and 0.78 for the cuff/apex and 0.98 for the cervix. There is good inter-examiner agreement of a simplified POPQ classification system and it appears to have good inter-system association with the POPQ.IUGA Standardization of Terminology Committee members: Robert Freeman MD (chairman), Steven Swift, Eckhard Petri MD, Richard J. Scotti MD, and Peter Dwyer MD.  相似文献   
12.
OBJECTIVE: To evaluate variations in prenatal care quality by public and private clinical settings and by household wealth. DESIGN: The study uses 2003 data detailing retrospective reports of 12 prenatal care procedures received that correspond to clinical guidelines. The 12 procedures are summed up, and prenatal care quality is described as the average procedures received by clinical setting, provider qualifications, and household wealth. SETTING: Low-income communities in 17 states in urban Mexico. PARTICIPANTS: A total of 1253 women of reproductive age who received prenatal care within 1 year of the survey. MAIN OUTCOME MEASURE: The mean of the 12 prenatal care procedures received, reported as unadjusted and adjusted for individual, household, and community characteristics. RESULTS: Women received significantly more procedures in public clinical settings [80.7, 95% confidence interval (CI) = 79.3-82.1; P < or = 0.05] compared with private (60.2, 95% CI = 57.8-62.7; P < or = 0.05). Within private clinical settings, an increase in household wealth is associated with an increase in procedures received. Care from medical doctors is associated with significantly more procedures (78.8, 95% CI = 77.5-80.1; P < or = 0.05) compared with non-medical doctors (50.3, 95% CI = 46.7-53.9; P < or = 0.05). These differences are independent of individual, household, and community characteristics that affect health-seeking behavior. CONCLUSIONS: Significant differences in prenatal care quality exist across clinical settings, provider qualifications, and household wealth in urban Mexico. Strategies to improve quality include quality reporting, training, accreditation, regulation, and franchising.  相似文献   
13.
Summary Twenty-two patients with recurrent or metastatic squamous cell carcinoma of the head and neck were treated with piroxantrone 150 mg/m2 intravenously every 21 days. There were no objective responses. The 95% upper confidence bound for response is 15%. Primary toxicity was hematologic.  相似文献   
14.
A1 INFLUENCE OF POSTURE ON REACTIONS IN NEW BLOOD DONORS. A2 A CONFIDENTIAL UNIT EXCLUSION SYSTEM IDENTIFIES DONORS WITH A POTENTIAL FOR HIV INFECTION. A3 A STABLE BLOOD SUPPLY FOR THE FUTURE: THE RECRUITMENT OF 16 TO 18 YEAR OLD DONORS TODAY AND THEI CONTRIBUTION AS COMMITTED REGULAR DONORS OF TOMORROW. A4 APPROACH TO A SUPPLY CRISIS OF HYPERIMMUNE RHESUS PLASMA FOR THE PRODUCTION OF RhD IMMUNOGLOBULIN A5 THE INFLUENCE OF AGE, SEX AND ABO BLOOD GROUP ON THE INCIDENCE OF CMV ANTIBODIES IN SYDNEY BLOOD DONORS. A6 THE INCIDENCE OF CATEGORY VI AMONGST WEAK Rh(D) POSITIVE SYDNEY BLOOD DONORS. A7 A MODIFIED METHOD FOR DETECTING HIGH TITRE ANTI-A AND ANTI-B IN GROUP O DONORS A8 IMPROVING THE CLINICAL SPECIFICITY OF ALANINE AMINO TRANSFERASE (ALT) TEST RESULTS WITHIN THE NORMAL BLOOD DONOR POPULATION OF QUEENSLAND. A9 EXTRACTION OF HCV RNA USING A GUANIDINE ISOTHIOCYNATE METHOD. A10 HEPATITIS C VIRUS (HCV) ANTIBODY DETECTION IN TASMANIAN BLOOD DONORS. A11 EFFECTIVE INTERNAL QUALITY CONTROL FOR ENZYME IMMUNOASSAYS A12 DETECTION OF ANTIBODY TO NON-PATHOGENIC RETROVIRUSES (SPUMAVIRUSES) IN HUMAN SERUM A13 DETECTION OF ANTIBODY TO NON-PATHOGENIC RETROVIRUSES (SPUMAVIRUSES) IN HUMAN SERUM A14 A NOVEL BLOOD BAG SYSTEM WITH POTENTIAL, FOR THE ASIA-PACIFIC MARKET. A15 DESIGN OF CONTAINERS SUITABLE FOR THE TRANSPORT OF RED CELL, PLATELET AND FROZEN PLASMA PRODUCTS. A16 EVALUATION OF INDICATOR LABELS FOR QUALITY ASSURANCE OF IRRADIATION PROCEDURE OF BLOOD PRODUCTS. A17 MOLECULAR TYPING FOR UNUSUAL ABO TYPES. A18 AN EXAMPLE OF THE RARE ABO SUBGROUP, A19 RFLP ANALYSIS OF A RH NULL BLOOD DONOR. A20 A RELATIONSHIP BETWEEN LEWIS ERYTHROCYTE PHENOTYPES AND COLORECTAL CANCER. A21 PATERNITY TESTING USING SINGLE LOCUS DNA PROBES: OBSERVATIONS ON THE REFERENCE DATA BASE SIZE A22 USE OF FAMILY AND POPULATION STUDIES TO DETERMINE THE SPECIFICITY AND INHERITANCE OF NEUTROPHIL ANTIGENS DEFINED BY PLANT LECTINS. A23 SAMPLING PLANS: IS THERE RELEVANCE FOR BLOOD COMPONENT QC? A24 QUALITY MANAGEMENT: HOW DO WE DO IT IN A STATE THE SIZE OF QUEENSLAND? A26 THE ENERGY METABOLISM OF CIRCULATING CELLS. A27 ACETATE UTILISATION RATES AND THE EFFECT OF GLUCOSE-FREE PLASMA IN PLATELET CONCENTRATE STORED IN A MIMIMAL MEDIUM (MPM). A28 IMPROVED LEVELS OF 2,3 DJPHOSPHOGLYCERATE IN RED CELL SUSPENSIONS PREPARED FROM BLOOD COLLECTED INTO DEXTROSE-FREE ANTICOAGULANT. A29 EVALUATION OF RED CELL FREEZING METHODS AS A PRELUDE TO ADOPTING -80° C FREEZING IN HIGH GLYCEROL IN ROUTINE PRACTICE. A30 CLUMPING IN PLATELET CONCENTRATES - AN UNSOLVED PROBLEM. A31 AUTOLOGOUS BLOOD: SAFE FOR OTHERS OR NOT? A32 ESTABLISHMENT OF AN AUSTRALIAN HAEMOPHILIA TREATMENT CENTRE DATA BANK. A33 EXPERIENCE IN THE USE OF ROBOTICS AND MICROPLATE TECHNOLOGY TO SEMI-AUTOMATE A ROUTINE HOSPITAL BLOOD BANK. A34 AN ANTI-IgAl/IgA2 ELISA ASSAY FOR THE INVESTIGATION OF HYPESENSITIVITY TRANSFUSION REACTIONS. A35 THE INFLUENCE OF IgG AGGREGATES AND FRESH NORMAL SERUM ON THE MONOCYTE MONOLAYER ASSAY A36 DETECTION OF Rh(D) POSITIVE FETAL CELLS IN PREGNANT Rh(D)-NEGATIVE WOMEN BY FLOW CYTOMETRY. A38 HAEMOSTAT-IX: A HIGH PURITY FACTOR CONCENTRATE FOR THE TREATMENT OF PATIENTS WITH HAEMOPHILIA B. A39 GRAVITY FILTRATION OF PLASMA FROM DONOR BLOOD UTILISING A HOLLOW FIBRE FILTER MEMBRANE DEVICE A40 The Therapeutic Device Problem Reporting Scheme, and the Victorian Red Cross Blood Bank A43 HIGH FREQUENCY ANTIBODIES AND THE ADVANTAGES OF MANUAL POLYBRENE. A44 FACTS AND FANTASY IN THE DEVELOPMENT OF PLATELET ADDITIVE SOLUTIONS. A45 LACK OF EFFECT OF STORAGE CONTAINER ON STORAGE OF PLATELETS PREPARED FROM DEXTROSE-FREE BLOOD, A46 PLATELETS PREPARED FROM DEXTROSE-FREE BLOOD MAY BE STORED WITHOUT AGITATION. A47 QUALITY OF BED CELL CONCENTRATE IN HOSPITALS COMPARED TO THE BLOOD BANK A48FLOW CYTOMETRIC CHARACTERISATION OF LEUCOCYTE - DEPLETED RED CELL CONCEHTRATES. A49 PRODUCTION AND CHARACTERISATION OF HUMAN MONOCLONAL ANTI-D ANTIBODIES. A50 CD55 AND CD59 SUSCEPTIBILITY TO PROTEASE TREATMENT AND THE RESULTANT EFFECT ON COMPLEMENT LYSIS OF RBCs. A51 DIRECT COMPARISON BETWEEN PLATELET STORAGE CONTAINERS - IMPROVEMENT IN STORAGE CHARACTERISTICS OF TUTA PLATELET BAGS OVER THE PAST FOUR YEARS. A52 IMPROVED SOLID-PHASE MIXED PASSIVE HAENAGGLUTININ ASSAY (MPHA) WITH FROZEN PANEL PLATELETS FOR THE DETECTION OF HUMAN PLATELET ANTIBODIES. A53 DEVELOPMENT OF A SOLVENT DETERGENT TREATED THROMBIN CONCENTRATE AS A COMPONENT OF A FIBRIN GLUE KIT. A54 Autologous blood transfusion: a promotional programme A55 AVAILABILITY OF BLOOD PRODUCTS FOR ACUTELY BLEEDING PATIENTS. A56 REMINISCENCES OF 50 YEARS A. A TRANSFUSION ST. A57 A NATIONAL SYSTEM FOR REPORTING TRANSFUSION REACTIONS TO FRACTIONATED BLOOD PRODUCTS. A58 EFFECT OF FLUORESCENT LIGHTING ON THE VISUAL APPEARANCE OF PLATELET CONCENTRATES A59 USING A MICROWAVE OVEN TO THAW FRESH FROZEN PLASMA. A60 COAGULATION CAPACITY OF POOLED PLATELET PLASMA. A61 A COMPARISON OF IMMUNOHAEMATOLOGY SURVEY PERFORMANCE BETWEEN NEK ZEALAND AND AUSTRALIA A62 COMPATIBILITY TESTING: ARE ENZYME TESTS REQUIRED? A63 AN EVALUATION OF THE DIAMED MEROTYPING SYSTEM FOR THE PERFORMANCE OF THE DIRKT ANTIGLOBUDIN TEST. A64 ASSESSMENT OF PERFORMANCE IN BLOOD GROUP ANTIBODY DETECTION. A65 CHARACTERISATION OF MABS TO THROMBIN-HIRUDIN COMPLEXES WITH IMMUNOASSAY POTENTIAL. A66 MONITORING ANTT-HPA-la (P1A1) PLATELET ANTIBODY LEVELS DURING PREGNANCY USING THE MAIPA TEST. A67 COMPARISON OF PIFT AND MAIPA TEST“ IN THE DETECTION OF ANTI-HPA-la (PIA1) PLATELET ANTIBODIES. A68 USE OF PLATELET-CROSSMATCHING IN SUPPORT OF A CASE OF MYELODYSPLASIA WTTH A PLATELET SPECIFIC AND B LYMPHOCYTE ANTIBODY A69 The Pattern of Leucocyte Antibody formation in Transfused Patients. A70 DETECTION OF HPA-Ia ANTIBODY IN BREAST MILK A71 ANALYSIS OF PRENATAL SCREENING. A72 DETECTION OF MINOR POPULATIONS OF ERYTHROCYTES A73 MODIFICATIONS TO THE MCNOCYTE-MEDIATED ADCC ASSAY. A74 AN AUTO ANTI-JMH; GAMMA-CLONE POLYSPECIFIC AHG AS A USEFUL TOOL. A75 CLINICALLY SIGNIFICANT ANTI-A1 DERIVED FROM B LYMPHOCYTES FOLLOWING SINGLE LUNG TRANSPLANTATION. A76 CONFIRMATION THAT ANTI-ELO CAUSES HAEMOLYTIC DISEASE OFTHE NEWBORN. A77 ANTI-Doa STIMULATED BY PREGNANCY. A78 DONOR IgM ANTI-A ASSOCIATED WITH HAEMOLYTIC TRANSFUSION REACTION A79 COLLECTION OF GRANULOCYTES AND PLATELETS USING FENWALL CS 3000 AND HAEMONETICS 30 CELL SEPARATORS - A COMPARISON. A80 APPARENT LYMPHOPENIA IN PLASMAPHERESIS DONORS  相似文献   
15.
16.
In view of the putative involvement of calcium in uremic encephalopathy and the critical importance of this element in juvenile development, we examined the effect of temporary restriction of dietary calcium intake on serum chemistry and the quantitative electroencephalogram (Q.EEG) in unilaterally 3/4 nephrectomized juvenile male Sprague-Dawley rats. Animals were renally infarcted at 22-26 days of age (50-74 g) and placed on one of two isocaloric dietary regimens: powdered normal rat diet (ND, n = 25) or low calcium diet (LCD, n = 8) for 30 days. At this time, ND animals showed normal serum chemistries, whereas LCD rats were hypocalcemic and azotemic with significantly elevated blood urea nitrogen (BUN) and serum creatinine concentrations and reduced renal creatinine clearance values. All animals thereafter received ND for 25-34 further days, during which time chronic Q.EEG electrodes were implanted. At the end of the common ND feeding period, serum chemistry values were equal and normal in both groups. The average theta/alpha ratio (TAR) of the overnight Q.EEG was assessed for 3 days. We found that the TAR of previously LCD animals was significantly elevated compared with ND rats. This indicates an encephalopathic slowing of the background rhythm of these animals. We conclude that, following restoration of a transient uremic and hypocalcemic episode induced by LCD feeding, the Q.EEG background frequency of juvenile renally impaired rats was abnormally slow after 30 days of ND feeding.  相似文献   
17.
18.
19.
20.
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