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   25797篇
  免费   2453篇
  国内免费   76篇
耳鼻咽喉   275篇
儿科学   646篇
妇产科学   354篇
基础医学   3130篇
口腔科学   833篇
临床医学   3376篇
内科学   5538篇
皮肤病学   618篇
神经病学   1886篇
特种医学   1121篇
外科学   3646篇
综合类   487篇
一般理论   24篇
预防医学   2698篇
眼科学   353篇
药学   1993篇
中国医学   28篇
肿瘤学   1320篇
  2021年   370篇
  2020年   209篇
  2019年   347篇
  2018年   403篇
  2017年   311篇
  2016年   368篇
  2015年   412篇
  2014年   554篇
  2013年   877篇
  2012年   1149篇
  2011年   1138篇
  2010年   674篇
  2009年   617篇
  2008年   1059篇
  2007年   1062篇
  2006年   1091篇
  2005年   1103篇
  2004年   1028篇
  2003年   982篇
  2002年   976篇
  2001年   990篇
  2000年   1008篇
  1999年   847篇
  1998年   355篇
  1997年   305篇
  1996年   291篇
  1995年   298篇
  1994年   228篇
  1993年   245篇
  1992年   623篇
  1991年   646篇
  1990年   602篇
  1989年   530篇
  1988年   508篇
  1987年   499篇
  1986年   489篇
  1985年   480篇
  1984年   351篇
  1983年   309篇
  1982年   220篇
  1981年   221篇
  1979年   325篇
  1978年   240篇
  1977年   211篇
  1976年   172篇
  1974年   214篇
  1973年   204篇
  1972年   169篇
  1971年   193篇
  1970年   170篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
We used the dual capability of hyperpolarized 129Xe for spectroscopy and imaging to develop new measures of xenon diffusing capacity in the rat lung that (analogously to the diffusing capacity of carbon monoxide or DLCO) are calculated as a product of total lung volume and gas transfer rate constants divided by the pressure gradient. Under conditions of known constant pressure breath-hold, the volume is measured by hyperpolarized 129Xe MRI, and the transfer rate is measured by dynamic spectroscopy. The new quantities (xenon diffusing capacity in lung parenchyma (DLXeLP)), xenon diffusing capacity in RBCs (DLXeRBC), and total lung xenon diffusing capacity (DLXe)) were measured in six normal rats and six rats with lung inflammation induced by instillation of fungal spores of Stachybotrys chartarum. DLXeLP, DLXeRBC, and DLXe were 56 +/- 10 ml/min/mmHg, 64 +/- 35 ml/min/mmHg, and 29 +/- 9 ml/min/mmHg, respectively, for normal rats, and 27 +/- 9 ml/min/mmHg, 42 +/- 27 ml/min/mmHg, and 16 +/- 7 ml/min/mmHg, respectively, for diseased rats. Lung volumes and gas transfer times for LP (TtrLP) were 16 +/- 2 ml and 22 +/- 3 ms, respectively, for normal rats and 12 +/- 2 ml and 35 +/- 8 ms, respectively, for diseased rats. Xenon diffusing capacities may be useful for measuring changes in gas exchange associated with inflammation and other lung diseases.  相似文献   
2.
3.
4.
Clinical decisions are often made with incomplete information, yet patient care decisions are made every day. Patients vary clinically, uncertainty exists in diagnostic and prognostic information, and many preventive and treatment alternatives have not been formally assessed for their effectiveness. Because scientific information will never answer all clinical questions, clinical decisions are partially based on probabilistic information.
This paper describes how to apply clinical decision making to diagnosing and managing dental caries and periodontal diseases. By using explicit information to quantify probabilities and outcomes, clinical decision making analyzes decisions made under uncertain conditions and the uncertain impact of clinical information.
Clinical decision making incorporates concepts for preventing, diagnosing and treating dental caries and periodontal diseases: risk assessment, evidence-based dentistry, and multiple oral health outcomes. This information can serve as a tool for clinicians to augment clinical judgment and expertise.  相似文献   
5.
6.
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   
7.
8.
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   
9.
10.
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