全文获取类型
收费全文 | 4506篇 |
免费 | 255篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 109篇 |
妇产科学 | 66篇 |
基础医学 | 621篇 |
口腔科学 | 78篇 |
临床医学 | 407篇 |
内科学 | 1313篇 |
皮肤病学 | 62篇 |
神经病学 | 359篇 |
特种医学 | 148篇 |
外科学 | 648篇 |
综合类 | 10篇 |
一般理论 | 2篇 |
预防医学 | 147篇 |
眼科学 | 123篇 |
药学 | 247篇 |
中国医学 | 7篇 |
肿瘤学 | 367篇 |
出版年
2023年 | 27篇 |
2022年 | 47篇 |
2021年 | 99篇 |
2020年 | 69篇 |
2019年 | 86篇 |
2018年 | 88篇 |
2017年 | 91篇 |
2016年 | 82篇 |
2015年 | 98篇 |
2014年 | 130篇 |
2013年 | 169篇 |
2012年 | 274篇 |
2011年 | 267篇 |
2010年 | 167篇 |
2009年 | 181篇 |
2008年 | 263篇 |
2007年 | 294篇 |
2006年 | 303篇 |
2005年 | 337篇 |
2004年 | 298篇 |
2003年 | 257篇 |
2002年 | 236篇 |
2001年 | 73篇 |
2000年 | 51篇 |
1999年 | 60篇 |
1998年 | 59篇 |
1997年 | 37篇 |
1996年 | 49篇 |
1995年 | 42篇 |
1994年 | 37篇 |
1993年 | 34篇 |
1992年 | 51篇 |
1991年 | 29篇 |
1990年 | 36篇 |
1989年 | 27篇 |
1988年 | 32篇 |
1987年 | 39篇 |
1986年 | 24篇 |
1985年 | 37篇 |
1984年 | 28篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1981年 | 16篇 |
1980年 | 13篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1975年 | 9篇 |
1972年 | 8篇 |
1971年 | 12篇 |
1967年 | 10篇 |
排序方式: 共有4803条查询结果,搜索用时 0 毫秒
11.
Gillingham MB Connor WE Matern D Rinaldo P Burlingame T Meeuws K Harding CO 《Molecular genetics and metabolism》2003,79(2):114-123
Current dietary therapy for long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) or trifunctional protein (TFP) deficiency consists of fasting avoidance, and limiting long-chain fatty acid (LCFA) intake. This study reports the relationship of dietary intake and metabolic control as measured by plasma acylcarnitine and organic acid profiles in 10 children with LCHAD or TFP deficiency followed for 1 year. Subjects consumed an average of 11% of caloric intake as dietary LCFA, 11% as MCT, 12% as protein, and 66% as carbohydrate. Plasma levels of hydroxypalmitoleic acid, hydroxyoleic, and hydroxylinoleic carnitine esters positively correlated with total LCFA intake and negatively correlated with MCT intake suggesting that as dietary intake of LCFA decreases and MCT intake increases, there is a corresponding decrease in plasma hydroxyacylcarnitines. There was no correlation between plasma acylcarnitines and level of carnitine supplementation. Dietary intake of fat-soluble vitamins E and K was deficient. Dietary intake and plasma levels of essential fatty acids, linoleic and linolenic acid, were deficient. On this dietary regimen, the majority of subjects were healthy with no episodes of metabolic decompensation. Our data suggest that an LCHAD or TFP-deficient patient should adhere to a diet providing age-appropriate protein and limited LCFA intake (10% of total energy) while providing 10-20% of energy as MCT and a daily multi-vitamin and mineral (MVM) supplement that includes all of the fat-soluble vitamins. The diet should be supplemented with vegetable oils as part of the 10% total LCFA intake to provide essential fatty acids. 相似文献
12.
Expression of actin isoforms and intermediate filament proteins in childhood orbital rhabdomyosarcomas 总被引:1,自引:0,他引:1
M Cintorino C Vindigni M T Del Vecchio P Tosi R Frezzotti T Hadjistilianou P Leoncini S Silvestri O Skalli G Gabbiani 《Journal of submicroscopic cytology and pathology》1989,21(3):409-419
The diagnosis of orbital rhabdomyosarcoma (RMS) in childhood gives rise to several clinical and anatomo-pathological problems. Antibodies recognizing structural proteins and cytoskeletal components have been shown to increase the diagnostic accuracy of different neoplastic lesions. In this study we examined anatomo-clinically and, where possible, by means of immunohistochemistry and electron microscopy, a series of 14 cases of orbital RMS in childhood. In the 12 cases studied by immunohistochemistry, desmin was always present, although showing variable patterns, and alpha-sarcomeric actin was found in 10 cases. alpha-Smooth muscle actin was always absent. The other markers tested (myoglobin, polyclonal actin, vimentin and enolase) proved unreliable for several reasons. We conclude that antibodies against desmin and alpha-sarcomeric actin are useful for the diagnostic definition of RMS. In addition, immunohistochemical analysis supplies data regarding the degree of tumor differentiation and may be applied to monitor radio- and chemotherapy. 相似文献
13.
14.
Burkitt's lymphomas express VH genes with a moderate number of antigen-selected somatic mutations. 总被引:7,自引:2,他引:7 下载免费PDF全文
J. Tamaru M. Hummel T. Marafioti B. Kalvelage L. Leoncini C. Minacci P. Tosi D. Wright H. Stein 《The American journal of pathology》1995,147(5):1398-1407
The normal counterpart of the neoplastic B cells occurring in Burkitt's lymphomas (BL) is an issue of controversial debate. To clarify this matter, a semi-nested primer polymerase chain reaction was performed to amplify the VDJ rearrangements of the immunoglobulin heavy chain (VH) gene of DNA extracts from 10 (8 sporadic and 2 endemic) BL cases. The resulting amplificates were sequenced for comparison with known germ line VH segments. The control cases comprised six cases of B cell chronic lymphocytic leukemia and six cases of mantle cell lymphoma known to display naive nonmutated, ie, pre-germinal center VH configurations; and eight cases of follicular center lymphoma known to display mutated VH genes with signs of a still-ongoing mutation reaction, characteristic for germinal center cells and lymphomas that derive therefrom. The results of this approach revealed that both sporadic and endemic BL express mutated VH genes with a mutation frequency considerably lower (4.9% and 5.4%, respectively) than that observed in follicular center lymphoma (11.8%). In addition, after subcloning the amplificates, sequence analysis revealed no signs of ongoing mutations. These results led us to conclude that the derivation of neoplastic B cells in BL is definitely not from naive, nonmutated pre-germinal center B cells. Instead, our findings support the view that BL cells stem either from early centroblasts that are arrested after an initial hypermutation reaction, or from germinal center B cells that have differentiated in terms of surface immunoglobulin profile and mutation pattern but not in terms of morphology and proliferation toward SIgM+ IgD- memory B cells because of the deregulated c-myc gene expression. 相似文献
15.
This research aimed to investigate the time course of the cortical activity level preceding spontaneous awakening as a function of age and state. Two groups of infants (1-4 and 9-14 weeks of age) were continuously monitored by polygraphic recording and behavioural observation during the night. The electroencephalographic (EEG) activity recorded by the C3-O1 lead was analysed through an automatic analysis method which provides, for each 30-s epoch, a single measure, time domain based, of the EEG synchronization. The EEG parameter values were computed in the 6 min preceding each awakening out of non-rapid eye movement (NREM) sleep and out of rapid eye movement (REM) sleep. The EEG background activity level did not change in the minutes preceding awakening out of REM sleep. Awakening out of NREM sleep was preceded by a change of EEG activity level in the direction of higher activation with different time course according to the age. Both REM and NREM sleep results suggest that a high level of EEG activity is a prerequisite for the occurrence of a spontaneous awakening. 相似文献
16.
Detection of Leishmania infantum kinetoplast DNA in laryngeal tissue from an immunocompetent patient
Guddo F Gallo E Cillari E La Rocca AM Moceo P Leslie K Colby T Rizzo AG 《Human pathology》2005,36(10):1140-1142
Mucosal leishmaniasis of the upper respiratory tract is usually associated with the visceral form or is found in immunosuppressed individuals. This report presents a case of isolated mucosal leishmaniasis in an immunocompetent patient, whose diagnosis mainly rested on histology and positive polymerase chain reaction result for Leishmania donovani in the laryngeal tissue. A 59-year-old man, who never lived outside Italy, showed a subglottic mucosal polypoid-like lesion. The typical morphological picture and positive polymerase chain reaction result for L donovani by DNA extracted from laryngeal biopsy specimens allowed the diagnosis of mucosal leishmaniasis. Specific amphotericin B therapy was started, resulting in clinical and endoscopic improvement. Increased knowledge about the histological and molecular tissue analysis of Leishmania enhances the diagnostic testing for mucosal leishmaniasis, as primary mucosal leishmaniasis may occur in both immunosuppresed and immunocompetent patients who travel to or reside in areas endemic for Leishmania. 相似文献
17.
A comparison between in vivo and ex vivo HR-MAS 1H MR spectra of a pediatric posterior fossa lesion 总被引:1,自引:0,他引:1
Tugnoli V Schenetti L Mucci A Nocetti L Toraci C Mavilla L Basso G Rovati R Tavani F Zunarelli E Righi V Tosi MR 《International journal of molecular medicine》2005,16(2):301-307
The present case report was aimed at identifying the molecular profile characteristic of a primitive neuro-ectodermal tumor (PNET) in a 3-year-old child affected by a lesion localized in the cerebellar region. The histological diagnosis was medulloblastoma. In vivo single voxel 1H magnetic resonance spectroscopy (MRS) shows high specificity in detecting the main metabolic alterations in the primitive cerebellar lesion; a very high amount of the choline-containing compounds and very low level of creatine derivatives and N-acetylaspartate. Ex vivo high resolution magic angle spinning (HR-MAS) 1H magnetic resonance spectroscopy, performed at 9.4 Tesla on the neoplastic specimen collected during surgery, allows for the unambiguous identification of several metabolites giving a more in-depth evaluation of the metabolic pattern of the lesion. The ex vivo HR-MAS MR spectra show that the spectral detail is much higher than that obtained in vivo and that, for example, myo-inositol, taurine and phosphorylethanolamine contribute to the in vivo signal at 3.2 ppm, usually attributed to choline-containing compounds. In addition, the spectroscopic data appear to correlate with some morphological features of the medulloblastoma. Consequently, the present study shows that ex vivo HR-MAS 1H MRS is able to strongly improve the clinical possibility of in vivo MRS and can be used in conjunction with in vivo spectroscopy for clinical purposes. 相似文献
18.
19.
Ernesto Falcidia Agata Grillo Piero Pavone Nunzio Cutuli Haruo Takabayashi Rosario R. Trifiletti Conrad T. Gilliam 《American journal of medical genetics. Part A》2001,101(3):262-267
The isolation and analysis of nucleated fetal cells (NFCs) from maternal blood may represent a new approach to noninvasive prenatal diagnosis. Although promising, these techniques require highly accurate separation of NFCs from nucleated cells of maternal origin; the two major problems limiting these techniques are the relative rarity of fetal cells in maternal blood and the need to establish their fetal origin. We now report a novel procedure that has allowed accurate separation of NFCs from maternal cells. The technique reported involves direct micromanipulator isolation of histochemically identified hemoglobin F‐positive nucleated cells to obtain fetal nucleated red blood cells (FNRBCs) of high yield and purity. Using this technique, followed by cell‐by‐cell multicolor fluorescence in situ hybridization (FISH) analysis of purified FNRBCs, we were able to detect some of the most common human aneuploidies (including Down syndrome, Klinefelter syndrome, and trisomy 13) in 33 pregnant women referred for amniocentesis. The procedure used, which can be completed in <72 hrs, produced complete concordance with the results of amniocentesis. We also confirm findings of prior studies suggesting that the number of FNRBCs in maternal circulation is remarkably higher in abnormal pregnancies than in normal pregnancies, especially in women carrying a fetus with trisomy 21. © 2001 Wiley‐Liss, Inc. 相似文献
20.
J J Asca?o H Frierson C A Moskaluk J C Harper F Roviello C E Jackson W El-Rifai C Vindigni P Tosi S M Powell 《Modern pathology》2001,14(10):942-949
Loss of the cell adhesion molecule E-cadherin has been observed in a variety of human carcinomas, and germline E-cadherin mutations have been found in several familial cases of diffuse gastric cancer. We sought to determine the prevalence and nature of E-cadherin alterations in "sporadic" gastric carcinomas. We performed comprehensive sequencing of the coding region, loss of heterozygosity (LOH) analysis, and immunohistochemical protein expression determination on 40 sporadic gastric adenocarcinomas. In total, 7 of 25 diffuse-type cancers harbored genetic alterations in the E-cadherin gene. Novel mutations predicted to significantly compromise protein function were found within 4 of these cancers, 2 of which harbored alterations resulting in biallelic inactivation of the gene product. Three diffuse cancers failed to amplify Exon 8 of E-cadherin, suggesting the presence of a homozygous abnormality. Notably, one germline E-cadherin mutation was also identified within these "sporadic" diffuse cancers. Significant gene mutations were not found in the 14 intestinal-type or histologically mixed cancer. Immunohistochemistry revealed aberrant or negative protein expression in seven diffuse-type tumors, four of which correlated with the genetic alterations. Both diffuse and intestinal-type tumors exhibited low rates of LOH, suggesting that allelic loss at the locus is not a common mechanism for E-cadherin inactivation during gastric tumorigenesis. Our observations suggest that inactivation of the E-cadherin gene occurs only in a subset of diffuse-type gastric cancers, as the majority of cases did not contain genetic alterations or identifiable protein abnormalities. Germline E-cadherin alterations, although rare, may underlie some diffuse gastric cancer cases that have important biologic and practical implications 相似文献