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   22622篇
  免费   1459篇
  国内免费   553篇
耳鼻咽喉   371篇
儿科学   517篇
妇产科学   265篇
基础医学   2358篇
口腔科学   528篇
临床医学   2550篇
内科学   3971篇
皮肤病学   807篇
神经病学   1653篇
特种医学   690篇
外国民族医学   2篇
外科学   1165篇
综合类   2758篇
现状与发展   3篇
一般理论   1篇
预防医学   2225篇
眼科学   1193篇
药学   2437篇
  6篇
中国医学   313篇
肿瘤学   821篇
  2024年   38篇
  2023年   246篇
  2022年   573篇
  2021年   753篇
  2020年   703篇
  2019年   708篇
  2018年   659篇
  2017年   635篇
  2016年   716篇
  2015年   772篇
  2014年   1309篇
  2013年   1673篇
  2012年   1198篇
  2011年   1331篇
  2010年   1148篇
  2009年   1101篇
  2008年   1165篇
  2007年   1108篇
  2006年   954篇
  2005年   815篇
  2004年   727篇
  2003年   620篇
  2002年   549篇
  2001年   469篇
  2000年   380篇
  1999年   364篇
  1998年   333篇
  1997年   313篇
  1996年   253篇
  1995年   255篇
  1994年   231篇
  1993年   238篇
  1992年   215篇
  1991年   189篇
  1990年   186篇
  1989年   194篇
  1988年   170篇
  1987年   155篇
  1986年   148篇
  1985年   170篇
  1984年   174篇
  1983年   108篇
  1982年   97篇
  1981年   85篇
  1980年   82篇
  1979年   77篇
  1978年   59篇
  1977年   51篇
  1976年   38篇
  1975年   48篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
The pre-operative risk of paediatric liver transplantation candidates (n=41) was assessed in a prospective study by means of clinical symptoms, conventional static and liver blood flow dependent dynamic liver function tests. Nine patients died during the 365-day waiting period. The data were subjected as covariates to a survival analysis in the Cox proportional hazards model. There was a significant relationsship between the results of mono-ethylglycinexylidide (MEGX) formation and ICG test and the 365-day survival rate. In the stepwise analysis, none of the remaining parameters improved the predictive ability when added to the dynamic liver function test results. The assessment of post-transplantation liver function was studied in 27 patients during the first 28 postoperative-day period. In addition, liver function was studied in a cross-sectional study 1–7 years after successful liver transplantation in children with complete or partial rehabilitation. In the early postoperative period severe organ damage was indicated by both static and dynamic liver function tests. In the later course after transplantation no deterioration of liver function measured with MEGX formation was to be observed. These findings demonstrate the usefulness of dynamic liver function tests in the pre- and post-transplant assessment of liver function.  相似文献   
12.
During an exposure monitoring study, 78 saw maintenance tradesmen were randomly assigned to be interviewed about their exposures using one of two questionnaire formats: open-ended and partly prompted questions about five categories of materials; and detailed prompting about 75 agents. The more open-ended questionnaire elicited fewer exposure responses overall, but more responses about agents not included on the detailed questionnaire. Composite materials and trade name products were more frequently cited as exposures than individual metals or compounds. Validity of responses was ascertained using air measurements (individual metals) or observations of the employees (composite materials). Sums of sensitivities and specificities were very low (near 1.0) for most of the metals for both types of questionnaire. For composite materials, validity improved substantially. Sensitivities with the partly prompted format (0.44–0.85) were always lower than with detailed prompting (0.80–1.00). Specificities were usually, but not always, higher with partial prompting (0.66–0.92) than with detailed prompting (0.18–0.86). Selection of questionnaire format for an epidemiologic study would depend on the likely prevalence of exposure in controls and the effects of trade-offs in sensitivity and specificity.  相似文献   
13.
Coeliac disease has been associated with a variety of neurological conditions, most frequently cerebellar ataxia and peripheral neuropathy. To date, chorea has not been associated with coeliac disease. We present the case histories of 4 individuals with coeliac disease and chorea (4 women, average age of onset of chorea 61 years). Unexpectedly, most of these patients showed a notable improvement in their motor symptoms after the introduction of a gluten-free diet.  相似文献   
14.
Autoimmune progesterone dermatitis is a rare condition, characterized by recurrent premenstrual exacerbations of a dermatosis, in which sensitivity to progesterone can be demonstrated. The sensitizing mechanism is unknown. The aim of this study was to test the hypothesis that cross-sensitivity between steroid groups could induce allergy to endogenous progesterone in these patients. 5 patients with autoimmune progesterone dermatitis and 1 with oestrogen-sensitive dermatitis have been patch tested with a corticosteroid series, conjugated oestrogen 1% in petrolatum (pet.), and 17-α-OH-progesterone 2% pet. There were no immediate or delayed reactions at 2 and 4 days to any steroid group. We have therefore been unable to demonstrate steroid cross-sensitivity, or a use for 17-α-OH-progesterone in the investigation of oestrogen - and progesterone-sensitive dermatoses.  相似文献   
15.
Ulrike Haun  Prof.  R. Rüchel  A. Spies 《Mycoses》1987,30(10):472-482
Summary: We describe a series of six serological tests for the diagnosis of deep-seated candidosis. The array comprises two commercial tests (antigen test, Ramco Inc., and antibody test, Roche), as well as four enzyme immunoassays which have been developed in this laboratory: an antigen test for detection of Candida-proteinase, the corresponding assays for monitoring of anti-proteinase antibodies, and two assays for monitoring of IgG and IgM against heterogenous metabolic antigens of C. albicans. The highly sensitive and specific proteinase antigen-test tolerates samples with high concentration of serum proteins. Proteinase antigen was detected in 10 out of 11 normal mice after intravenous infection with C. albicans blastospores. The proteinase antigen peaked between the second and fourth day after infection. A rise in corresponding antibodies was observed in all animals. No proteinase antigen was detected in sera of healthy human individuals; anti-proteinase antibody titers in these sera amounted up to 1:8000. In related ELISAs, using metabolic fungal antigens, titer values of specific IgG and IgM amounted to 5120 and 1280, respectively. The six tests were carried out in an comparative study under diagnostic conditions, the results of which are the subject of a forthcoming communication. Zusammenfassung: Ein Satz von sechs serologischen Tests für die Diagnostik der tiefen Candida-Mykosen wird vorgestellt. Die Gruppe schließt zwei kommerziell vertriebene Testbestecke ein (Latex-Agglutinationstest zum Antigennachweis, Ramco Inc., und Hämagglutinationstest zum Antikörpernachweis, Roche). Vier weitere Enzymimmuntests wurden von uns entwickelt: Ein Antigentest zum Nachweis von sekretorischer Candida-Protease, ein entsprechender Test zum Nachweis von Antikörpem gegen Candida-Protease, und zwei Assays zum Nachweis von IgG-bzw. IgM-Antikörpem gegen heterogene metabolische Antigene von C. albicans. Der empfindliche spezifische Protease-Antigentest toleriert hohe Konzentrationen unspezifischer Serumproteine und kann deshalb auf Serumproben in geringer Verdünnung (z. B. 1:20) angewandt werden. Protease-Antigen war in 200 fach verdünnten Seren von 10 aus 11 intravenös infizierten NWNI-Mäusen nachweisbar. Die höchste Antigen-Konzentration trat zwischen dem 2. und 4. Tag nach Infektion auf; die Serum-Halbwertszeit von gereinigter Protease in der Maus betrug etwa 60 nun. Ein Anstieg korrespondierender Antikörper war in alien infizierten Tieren zu beobachten. Auch im Serum gesunder Probanden waren Antiprotease-Antikörper bis zu einem Titer von 1:8000 nachweisbar; der Protease-Antigentest fiel hingegen immer negativ aus. Die Titer von Antikörpern gegen metabolische Candida-Antigene erreichten in derselben Gruppe von Seren Werte von 1:5120 bzw. 1:1280. Die sechs Tests wurden unter diagnostischen Bedingungen verglichen; Ergebnisse dieser Studie sind Gegenstand einer weiteren Mitteilung.  相似文献   
16.
The glucose clamp technique is currently regarded as the standard test for measuring insulin sensitivity against which other methods are compared but is unsuitable for routine screening of patients outside a hospital base. There is thus a need for a simpler test to measure insulin sensitivity. We have therefore compared the glucose disappearance rate KITT in the first 15 min of the insulin tolerance test (ITT) with the M and M/I values derived from the standard euglycaemic clamp in nine normal subjects and eight subjects with Type 2 (non-insulin dependent) diabetes mellitus and coexisting obesity. All subjects underwent the ITT and euglycaemic clamp in random order. Nine subjects later had a repeat ITT to determine the reproducibility of the test. In the ITT, 0.1 U kg-1 body weight, human Actrapid insulin was given as an IV bolus and simultaneous arterialized and venous blood samples were obtained every minute for 15 min. The first order rate constant for the disappearance of glucose KITT over the period 3-15 min was taken as a measure of insulin sensitivity. The euglycaemic clamp was performed with an insulin infusion of 50 mU kg-1 h-1 for 120 min and a variable rate glucose infusion to maintain blood glucose concentration at 0.5 mmol l-1 below fasting level to minimize the effect of endogenous insulin secretion. The ratio of the mean rate of glucose infused (M, mumol kg-1 min-1) to the plasma insulin over the last 30 min of the clamp was taken as a measure of tissue sensitivity to insulin (M/I) assuming endogenous glucose output was suppressed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
17.
Colour discrimination and visual contrast perception were investigated in 18 patients with Huntington's disease (HD) and in 18 age- and sex-matched healthy volunteers using the Farnsworth-Munsell 100 Hue test (FM) and stationary contrast targets. The mean total error score (MTES) and the partial scores for the “red-green” and the “blue-yellow” axes in the FM of the patients with HD were significantly elevated as compared to controls (MTES in HD: 113.0 ± 90.8; MTES in controls: 19.2 ± 8.8). The spatial contrast sensitivity in HD patients was normal. The colour perception dysfunction indicates that the visual system is affected in HD. The visual disorder may be related to an imbalance of certain neurotransmitters in the visual system of HD patients. Possible anatomical sites of the dysfunction responsible for colour discrimination abnormalities could be the retinal cone system and/or impaired parvocellular central visual pathways in HD.  相似文献   
18.
An 8-year longitudinal study of elderly people has provided data concerning age-associated impairment (AAMI). In 1985 a random sample of 146 persons aged 65 years or more, living in their own homes, were assessed using the Guild Memory Test the Mini–Mental State Examination (MMSE) and other ratings. After excluding 21% of the sample because they scored less than 24 on the MMSE, and another 34% who fulfilled other exclusion criteria, some 48% of the remainder (22% of the total sample) clearly fulfilled NIMH criteria for AAMI and a further 36% (16% of the total sample) were recorded as forgetful. The NIMH criteria are appropriate for certain research purposes but not in assessing prevalence of memory disorders. Follow–up interviews were conducted after 2, 4, 6 and 8 years. The mortality rate and development of dementia among those fulfilling criteria for AAMI appeared similar to the other non-demented groups of subjects; the mortality rate of those with MMSE scores below 24 was significantly higher. Guild test results at 2-yearly intervals showed considerable changes; half of those scoring least well who were retested showed improvement.  相似文献   
19.
BACKGROUND: Food allergy to cherry occurs throughout Europe, typically with restricted oral reactions in the central and northern parts but with frequent systemic reactions in the Mediterranean region. Previous studies have demonstrated insufficient sensitivity of commercially available cherry extract reagents in the diagnosis of cherry allergy. OBJECTIVE: To assess the diagnostic performance of specific IgE tests based on recombinant cherry allergens in comparison with an extract-based assay and to skin prick test (SPT). A secondary objective was to analyse the frequency of systemic reactions in cherry-allergic subjects across Europe, including the largest population of LTP-sensitized subjects from central Europe studied to date. METHODS: A total of 186 subjects from central Europe and Spain were studied. Serum IgE was analysed with ImmunoCAP tests carrying rPru av 1, 3 and 4, combined and separately, and cherry extract. RESULTS: Among the central European cherry allergics, the mix of rPru av 1, 3 and 4 had a sensitivity of 95%, compared with 65% for cherry extract, and the IgE binding capacity of the recombinant mix was considerably higher. The sensitivity of the two tests was more comparable in the Spanish population, 95% and 86%, respectively. The recombinant allergen ImmunoCAP equalled SPT in terms of sensitivity and specificity. Consistent with previous reports, major geographic differences in sensitization pattern and prevalence of systemic reactions were found. A significantly higher rate of systemic reactions was found in Spanish patients sensitized to Pru av 3 whereas German patients sensitized to LTP only had oral allergy syndrome. CONCLUSIONS: The recombinant cherry allergen ImmunoCAP is a highly sensitive diagnostic tool, clearly superior to any diagnostic method based on cherry extract. Three cherry allergens are sufficient for detecting sensitization in 95% of cherry-allergic subjects. Systemic reactions are common in LTP-sensitized individuals but seem to require at least one additional causative factor.  相似文献   
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