全文获取类型
收费全文 | 8406篇 |
免费 | 642篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 114篇 |
儿科学 | 204篇 |
妇产科学 | 223篇 |
基础医学 | 1318篇 |
口腔科学 | 144篇 |
临床医学 | 761篇 |
内科学 | 1877篇 |
皮肤病学 | 111篇 |
神经病学 | 787篇 |
特种医学 | 266篇 |
外科学 | 1188篇 |
综合类 | 111篇 |
现状与发展 | 1篇 |
一般理论 | 14篇 |
预防医学 | 708篇 |
眼科学 | 228篇 |
药学 | 471篇 |
中国医学 | 8篇 |
肿瘤学 | 547篇 |
出版年
2023年 | 95篇 |
2022年 | 179篇 |
2021年 | 295篇 |
2020年 | 171篇 |
2019年 | 294篇 |
2018年 | 307篇 |
2017年 | 187篇 |
2016年 | 199篇 |
2015年 | 248篇 |
2014年 | 303篇 |
2013年 | 428篇 |
2012年 | 550篇 |
2011年 | 612篇 |
2010年 | 282篇 |
2009年 | 301篇 |
2008年 | 456篇 |
2007年 | 521篇 |
2006年 | 435篇 |
2005年 | 462篇 |
2004年 | 477篇 |
2003年 | 418篇 |
2002年 | 405篇 |
2001年 | 74篇 |
2000年 | 63篇 |
1999年 | 70篇 |
1998年 | 78篇 |
1997年 | 69篇 |
1996年 | 56篇 |
1995年 | 60篇 |
1994年 | 55篇 |
1993年 | 52篇 |
1992年 | 40篇 |
1991年 | 35篇 |
1990年 | 35篇 |
1989年 | 47篇 |
1988年 | 40篇 |
1987年 | 48篇 |
1986年 | 31篇 |
1985年 | 28篇 |
1984年 | 37篇 |
1983年 | 35篇 |
1982年 | 33篇 |
1981年 | 31篇 |
1980年 | 25篇 |
1978年 | 25篇 |
1977年 | 25篇 |
1976年 | 28篇 |
1974年 | 27篇 |
1973年 | 29篇 |
1971年 | 23篇 |
排序方式: 共有9081条查询结果,搜索用时 15 毫秒
41.
Daphné Lehalle Roberto Colombo Michael O'Grady Bénédicte Héron Nada Houcinat Paul Kuentz Sebastien Moutton Arthur Sorlin Julien Thevenon Julian Delanne Sebastien Gay Caroline Racine Aurore Garde Frédéric Tran Mau‐Them Christophe Philippe Antonio Vitobello Sophie Nambot Frédéric Huet Yannis Duffourd François Feillet Christel Thauvin‐Robinet Sandrine Marlin Laurence Faivre 《American journal of medical genetics. Part A》2019,179(9):1756-1763
Alpha‐mannosidosis (AM) is a very rare (prevalence: 1/500000 births) autosomal recessive lysosomal storage disorder. It is characterized by multi‐systemic involvement associated with progressive intellectual disability, hearing loss, skeletal anomalies, and coarse facial features. The spectrum is wide, from very severe and lethal to a milder phenotype that usually progresses slowly. AM is caused by a deficiency of lysosomal alpha‐mannosidase. A diagnosis can be established by measuring the activity of lysosomal alpha‐mannosidase in leucocytes and screening for abnormal urinary excretion of mannose‐rich oligosaccharides. Genetic confirmation is obtained with the identification of MAN2B1 mutations. Enzyme replacement therapy (LAMZEDER) was approved for use in Europe in August 2018. Here, we describe seven individuals from four families, diagnosed at 3–23 years of age, and who were referred to a clinical geneticist for etiologic exploration of syndromic hearing loss, associated with moderate learning disabilities. Exome sequencing had been used to establish the molecular diagnosis in five cases, including a two‐sibling pair. In the remaining two patients, the diagnosis was obtained with screening of urinary oligosaccharides excretion and the association of deafness and hypotonia. These observations emphasize that the clinical diagnosis of AM can be challenging, and that it is likely an underdiagnosed rare cause of syndromic hearing loss. Exome sequencing can contribute significantly to the early diagnosis of these nonspecific mild phenotypes, with advantages for treatment and management. 相似文献
42.
Erwin EA Custis NJ Satinover SM Perzanowski MS Woodfolk JA Crane J Wickens K Platts-Mills TA 《The Journal of allergy and clinical immunology》2005,115(5):1029-1035
BACKGROUND: Commercially available assays for IgE antibody provide results in international units per milliliter for many allergen extracts, but this is not easily achieved with purified or novel allergens. OBJECTIVE: To develop assays for IgE antibody suitable for purified or novel allergens by using a commercially available immunosorbent. METHODS: Streptavidin coupled to a high-capacity immunosorbent (CAP) was used to bind biotinylated purified allergens from mite (Der p 1 and Der p 2), cat (Fel d 1), and dog (Can f 1). Assays for IgE antibody to these allergens were performed on sera from children (asthma and control) as well as adults with atopic dermatitis. RESULTS: The results were validated by serial dilution of sera with high and low levels of IgE antibody and were quantitated in international units per milliliter by using a standard curve. Values for IgE antibody to Der p 1, Der p 2, and Fel d 1 correlated with values obtained with the allergen extracts (r2 = 0.80, 0.84, and 0.95, respectively; P < .001 in each case). Furthermore, the values for IgE antibody in sera from children with high exposure to mite and cat allergens demonstrated 10-fold higher levels of IgE antibody to Der p 1 and Der p 2 than to Fel d 1 (P < .001). CONCLUSION: The streptavidin immunosorbent technique provides a new method for quantifying IgE antibody to purified proteins. The results provide evidence about the high quantities of IgE antibody to purified inhalant allergens in patients with atopic dermatitis. In addition, the results demonstrate major differences in IgE antibodies specific for mite and cat allergens among children with high exposure to both allergens. 相似文献
43.
This article reviews recent studies on the importance of glycine receptors for both the spontaneous and the reflex respiratory modulation of the laryngeal abductors and adductors. Our findings show that strychnine blockade of glycine receptors within the brainstem changes the eupneic three-phase respiratory pattern into two phases. This has major implications for glottal control: (i) the inspiratory glottic abduction and early expiratory adduction were both compromised--a finding mimicked by 5% hypoxia; (ii) closure of the glottis during defensive upper airway reflexes became intermittent and the reflex apnoea reversed to sustained inspiratory discharge. Based on these data, we predict that periods of prolonged hypoxia, such as those that occur during sleep apnoeas, will constrain inspiratory glottic abduction thereby impeding inhalation. 相似文献
44.
Ellen R Julian Deborah J Ingersoll Patricia M Etienne Anthony E Hilger 《Academic medicine》2004,79(4):360-364
PURPOSE: Medical College Admission Test (MCAT) examinees with disabilities who receive accommodations receive flagged scores indicating nonstandard administration. This report compares MCAT examinees who received accommodations and their performances with standard examinees. METHOD: Aggregate history records of all 1994-2000 MCAT examinees were identified as flagged (2,401) or standard (297,880), then further sorted by race/ethnicity (broadly identified as underrepresented minority and non-URM, at the time of testing) and gender. Those with flagged scores were also classified by disability (LD = learning disability, ADHD = attention deficit hyperactivity disorder, LD/ADHD = learning disability and attention deficit hyperactivity disorder, and Other = other disability) and type of accommodation. Mean MCAT scores were calculated for all groups. A group of 866 examinees took the MCAT first as a standard administration and subsequently with accommodations. In a separate analysis, their two sets of scores were compared. RESULTS: Less than 1% of examinees (2,401) had accommodations; of these, 55% were LD, 17% ADHD, 5% LD/ADHD, and 23% Other. Extended time was the most frequently provided accommodation. Mean flagged scores slightly exceeded mean standard scores on all MCAT sections. Examinees who retook the MCAT with accommodations after a standard administration increased their scores by six points, quadrupling the average gain Standard-Standard retest cohort from another study. CONCLUSION: The small but statistically significant different higher flagged scores may reflect either appropriate compensation or overly generous accommodations. Extended time had a positive impact on the scores of those who retested with this accommodation. The validity the flagged MCAT in predicting success in medical school is not known, and further investigation is underway. 相似文献
45.
Emotion-modulated startle is a robust phenomenon that has been demonstrated in a wide range of experimental situations. Similarly, heart rate variability (HRV) has been associated with a diverse range of processes including affective and attentional regulation. The present study sought to examine the relationship between these two important measures of affective behavior. Ninety female participants viewed pleasant, neutral, and unpleasant pictures while exposed to acoustic startle stimuli. The eyeblink startle was recorded both during the affective foregrounds and during intertrial intervals. HRV was assessed during a resting baseline and relationships between HRV and startle magnitudes examined. Results indicated that resting HRV was inversely related to startle magnitude during both intertrial intervals and affective foregrounds. In addition, the participants with the highest HRV showed the most differentiated emotion-modulated startle effects, whereas those with the lowest HRV, compared to those with the highest HRV, showed significantly potentiated startle to neutral foregrounds and marginally potentiated startle to pleasant foregrounds. The findings are consistent with models that posit that prefrontal cortical activity modulates subcortical motivation circuits. These results have important implications for the use of startle probe methodology and for HRV in the study of emotional regulation and dysregulation. 相似文献
46.
47.
A comparison of three months of anticoagulation with extended anticoagulation for a first episode of idiopathic venous thromboembolism 总被引:30,自引:0,他引:30
Kearon C Gent M Hirsh J Weitz J Kovacs MJ Anderson DR Turpie AG Green D Ginsberg JS Wells P MacKinnon B Julian JA 《The New England journal of medicine》1999,340(12):901-907
BACKGROUND: Patients who have a first episode of venous thromboembolism in the absence of known risk factors for thrombosis (idiopathic thrombosis) are often treated with anticoagulant therapy for three months. Such patients may benefit from longer treatment, however, because they appear to have an increased risk of recurrence after anticoagulant therapy is stopped. METHODS: In this double-blind study, we randomly assigned patients who had completed 3 months of anticoagulant therapy for a first episode of idiopathic venous thromboembolism to continue receiving warfarin, with the dose adjusted to achieve an international normalized ratio of 2.0 to 3.0, or to receive placebo for a further 24 months. Our goal was to determine the effects of extended anticoagulant therapy on rates of recurrent symptomatic venous thromboembolism and bleeding. RESULTS: A prespecified interim analysis of efficacy led to the early termination of the trial after 162 patients had been enrolled and followed for an average of 10 months. Of 83 patients assigned to continue to receive placebo, 17 had a recurrent episode of venous thromboembolism (27.4 percent per patient-year), as compared with 1 of 79 patients assigned to receive warfarin (1.3 percent per patient-year, P<0.001). Warfarin resulted in a 95 percent reduction in the risk of recurrent venous thromboembolism (95 percent confidence interval, 63 to 99 percent). Three patients assigned to the warfarin group had nonfatal major bleeding (two had gastrointestinal bleeding and one genitourinary bleeding), as compared with none of those assigned to the placebo group (3.8 vs. 0 percent per patient-year, P=0.09). CONCLUSIONS: Patients with a first episode of idiopathic venous thromboembolism should be treated with anticoagulant agents for longer than three months. 相似文献
48.
Volker Schmidt Susanne Schneider Julian Schlömer Maria-Elisabeth Krautwald-Junghanns Elvira Richter 《Avian pathology》2008,37(6):589-592
The present report describes a case of Mycobacterium tuberculosis infection in an African Grey parrot (Psittacus erithacus erithacus) kept as a pet bird. Diagnosis was confirmed by microbiologic and pathologic results, and indicated a human–avian transmission. Clinical signs included sublingual nodules resulting in anorexia and signs of osteolysis in the long bones. Proliferation consisted of several nodules with small greenish-caseous foci in cross-section and revealed a severe granulomatous inflammation without intralesional acid-fast rods. M. tuberculosis was cultured from a pooled sample of sublingual and liver nodules, and was confirmed via polymerase chain reaction. Transmission between men and parrot was proved by spoligotyping pattern analysis. The absence of facial skin lesions and acid-fast rods within the tubercles is contrary to previous publications of tuberculosis in birds. This disease in a common pet bird species is of zoonotic importance, and those parrots with close contact to owners suffering from tuberculosis may serve as a potential reservoir for human infection. 相似文献
49.
Reading Julian P.; Huffman John L.; Wu Joy C.; Palmer Frances T.; Harton Gary L.; Sisson Michael E.; Keyvanfar Keyvan; Gresinger Thomas H.; Cochrane William J.; Fallon Lee A.; Menapace-Drew Gianna F.; Cummings Emilie A.; Jones Shirley L.; Black Susan H.; Schulman Joseph D.; Levinson Gene 《Molecular human reproduction》1995,1(7):362-367
The discovery of nucleated erythrocytes in maternal circulationprovides a potential source for non-invasive prenatal diagnosis.We have evaluated the use of a three-stage procedure to determinethe number of cells that are of fetal rather than maternal origin.First, monoclonal antibodies specific for CD45 and CD14 wereused in conjunction with a magnetic (MACS) column to depleteunwanted leukocytes from maternal blood. This was followed bya positive MACS enrichment for nucleated erythrocytes, usingan anti-CD71 (transferrin receptor) monoclonal antibody. Todiscriminate between fetal nucleated erythrocytes and thoseof maternal origin, enriched fractions were simultaneously stainedwith an anti-fetal haemoglobin (HbF) antibody and hybridizedwith probes specific for X and Y chromosomes. Samples were thensubjected to blind analysis along with negative control samplesfrom non-pregnant volunteers. Using this dual analysis, we wereable to determine that less than one nucleated erythrocyte perml of maternal blood was of fetal origin. Small numbers of thesefetal cells were found in 87.5% of pregnancies, ranging from6 to 35 weeks gestational age. Comparison of HbF and X/Y probedata also suggests that the fetal cells are less suitable forfluorescence in-situ hybridization (FISH) analysis than similarpreparations from other sources. cell separation methods/fluorescence in-situ hybridization/hereditary diseases/polymerase chain reaction/pregnancy 相似文献
50.
Negative selection by endogenous antigen and superantigen occurs at multiple thymic sites 总被引:1,自引:0,他引:1
Douek Daniel C.; Corley Kevin T. T.; Zal Tomasz; Mellor Andrew; Dyson P. Julian; Altmann Daniel M. 《International immunology》1996,8(9):1413-1420
The site of negative selection in the thymus has been inferredfrom a range of different experiments. Analysis of thymic deletionof Vß5+, Vß11+ or Vß17a+ cellsH-2E transgenic mice led to the theory that negative selectionoccurs predominantly in the medulla (specifically, through presentationby medullary dendritic cells). Other experiments investigatedwhether transgenic TCR are deleted at the double-positive (DP)or single-positive stage following encounter with peptide ligand:by flow cytometric analysis deletion is generally found to occurat the DP thymocyte stage and as these cells are found predominantlyin the cortex, it has been inferred that this is the key siteof negative selection. The visualization of apoptotic thymocytesin situ has recently been reported for specific examples ofnegative selection. Using a panel of TCR transgenic lines inwhich negative selection occurs at different stages of thymocytedevelopment, we have used TUNEL staining to analyse the anatomicalsites of thymocyte apoptosis. For the first time we have beenable to compare directly the sites of deletion induced by theendogenous cognate peptides or by endogenous superantigen. Weshow that generalization from the medullary deletion of Vß5+,Vß11+ or Vß17a+ cells by the endogenoussuperantigens Mtv 8 and 9 and from limited examples of corticaldeletion by exogenous peptide administered to TCR transgenicmice is over-simplified. Apoptotic thymocytes in mice lackingMtv superantigens are indeed localized in the cortex. However,when deletion is induced by cognate self peptide, apoptosiscan occur in the cortex, the medulla or at the junction betweenthe two. 相似文献