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   716篇
  免费   21篇
  国内免费   1篇
儿科学   115篇
妇产科学   1篇
基础医学   30篇
口腔科学   4篇
临床医学   82篇
内科学   177篇
皮肤病学   6篇
神经病学   57篇
特种医学   1篇
外科学   125篇
综合类   4篇
预防医学   3篇
眼科学   2篇
药学   75篇
中国医学   4篇
肿瘤学   52篇
  2017年   4篇
  2016年   9篇
  2015年   14篇
  2014年   9篇
  2013年   14篇
  2012年   4篇
  2011年   3篇
  2010年   15篇
  2009年   18篇
  2008年   4篇
  2007年   28篇
  2006年   38篇
  2005年   19篇
  2004年   33篇
  2003年   24篇
  2002年   10篇
  2001年   9篇
  2000年   3篇
  1999年   32篇
  1998年   65篇
  1997年   41篇
  1996年   51篇
  1995年   42篇
  1994年   39篇
  1993年   37篇
  1992年   15篇
  1991年   15篇
  1990年   14篇
  1989年   6篇
  1988年   8篇
  1987年   10篇
  1986年   12篇
  1985年   8篇
  1984年   6篇
  1983年   4篇
  1982年   5篇
  1981年   13篇
  1980年   10篇
  1979年   14篇
  1978年   5篇
  1977年   2篇
  1976年   5篇
  1975年   2篇
  1973年   2篇
  1972年   4篇
  1971年   3篇
  1970年   2篇
  1967年   2篇
  1957年   2篇
  1954年   1篇
排序方式: 共有738条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: There are only a few reports discussing the characteristics of intussusception developing in school-age children. The characteristics of these cases are discussed, with reference to previous literature. METHODS: The present study included eight cases of intussusception in school-age children among 143 intussusception patients treated on an inpatient basis at Nihon University Itabashi Hospital, during the 11 year period from 1993 to 2003. The remaining 135 patients were assigned to the infant group as controls. The clinical characteristics of intussusception in school-age children were compared with those of the condition developing in infants. RESULTS: The eight children of school age with intussusception ranged in age from 8 to 15 years (mean, 11.6 years), and consisted of five boys and three girls. The major symptom was abdominal pain, occurring in 100% (8/8). Bloody stools and vomiting were reported in two patients each (25%) from this group. The triad of abdominal pain, bloody stools and vomiting was recognized in only one child (12.5%) of this group. Two children (25.0%) had a palpable abdominal mass, and one child (12.5%) complained of diarrhea. None of the school-age children with intussusception had any antecedent infection; five, two and one patients had the ileo-colic type, ileo-ileo-colic type and ileo-ileal type of intussusception, respectively. Four underwent enema reduction and four underwent surgical reduction. One of the eight children (12.5%) had underlying organic abnormality; in the remaining children the condition was labeled idiopathic. One child developed recurrences. CONCLUSIONS: In school-age children intussusception is generally believed to be commonly secondary to underlying organic abnormality, but in the present study only one of eight school-age children had underlying organic abnormality; in the remaining children, the condition was labeled idiopathic. The major symptom in school-age intussusception was abdominal pain. Therefore this may need to be differentiated from appendicitis in children of school age. It is considered that abdominal ultrasonography (USG) is a simple and useful method for making the diagnosis of intussusception, and that diagnostic USG should be conducted in all school-age children presenting with acute abdominal pain.  相似文献   
62.
BACKGROUND: The three major signs of hemolytic uremic syndrome (HUS) are hemolytic anemia, thrombopenia and acute renal failure. HUS is classified into Shiga toxin-mediated HUS (Stx-HUS) and non-Shiga toxin-mediated HUS (nStx-HUS). The prognosis of nStx-HUS is reported to be less favorable than that of Stx-HUS. Although the association between the prognosis and pathological characteristics of HUS have been reported such that the prognosis was considered to be poor for thrombotic microangiopathy (TMA) with predominant arterial involvement (arterial TMA), good for TMA with predominant glomerular involvement (glomerular TMA) and dependent on the extent of necrosis in cases of renal cortical necrosis, it is not yet clear whether pathological findings are also related to the renal prognosis of nStx-HUS cases. Therefore the purpose of the present paper was to analyze renal biopsy findings and prognosis for five children with nStx-HUS. METHODS: Clinical records of five cases of nStx-HUS among 74 cases of diagnosed HUS were reviewed, and information and data were summarized. RESULTS: Histological examination of the kidney led to the diagnosis of arterial TMA in three cases, and glomerular TMA and severe renal cortical necrosis in one case each. Analysis of the relationship between renal histological findings and the prognosis found that three patients with arterial TMA and one patient with severe renal cortical necrosis later developed end-stage renal failure while one patient with glomerular TMA has continued to show normal renal function. CONCLUSIONS: These findings indicate that pathological findings are closely related to the prognosis in cases of nStx-HUS.  相似文献   
63.
Abstract  Although respiration in trained canines is well investigated, the process of preparing dogs has not been described in any great detail. Moreover, their daytime patterns of sleep and wakefulness during 1 or 2 h of electroencephalogram (EEG) and electrocardiogram (ECG) recordings are not clear. Therefore, we describe the process of selecting and training dogs, in which we recorded EEG and ECG in the laboratory. First, 14 of 1242 dogs dealt with over a 1 year period were chosen. They were trained for 2 h to lie quietly and to sleep in the laboratory; this training procedure was repeated 152 times. Three dogs were then selected and a permanent tracheostomy was performed in one. Finally, EEG and ECG were recorded with the bipolar fine needle electrodes; respiration was recorded simultaneously through a tube inserted to a tracheostomy in one dog. Wakefulness, slow wave sleep (SWS) and rapid eye movement (REM) sleep (REMS) were identified according to the EEG pattern and on the basis of the behavioral criteria. Recordings were performed 12 or 13 times in each dog. Complete sleep cycles, including wakefulness, SWS and REMS in this sequence, were observed 3.9–4.1 times. The mean duration of SWS was 2.2–4.4 min and that of REMS was 3.5–4.6 min. The REMS latency was 33.9–41.8 min. Fluctuation of heart rate with respiration, termed respiratory sinus arrhythmia, was noted in the ECG. Heart beat increased with inspiration and decreased with expiration. The present study demonstrates how to select and train sleeping dogs and shows their undisturbed daytime sleep and wakefulness patterns.  相似文献   
64.
Unfolding profiles of two calcium-binding lysozymes, equine milk lysozyme and pigeon egg-white lysozyme, were obtained by circular dichroism and proton NMR measurements. Equine lysozyme unfolds through a stable molten globule intermediate. The molten globule of equine lysozyme was characterized as more ordered than that of bovine α-lactalbumin. On the other hand, pigeon lysozyme unfolds by a two-state mechanism and the intermediate could not be observed in guanidine or thermal unfolding, the same as with conventional non-calcium-binding lysozymes. Thus, from the point of view of the unfolding profile, equine lysozyme belongs to the group of α-lactalbumin, but pigeon lysozyme belongs to the conventional lysozyme group.  相似文献   
65.
Urinary levels of a,-microglobulin (αlM) and of ulinastatin (UT) and the αlM/UT ratio did not differ significantly between age-matched controls and patients with Parkinson's disease, and among subdivided groups based on Yahr's stages in Parkinson's disease. Furthermore, these indexes did not correlate with Yahr's stages. Although αlM and UT levels did not correlate in patients with Parkinson's disease, a positive correlation was observed in the control group. The non-existence of a positive correlation between αlM and UT levels distinguishes Parkinson's disease from other neuropsychiatric diseases such as dementia (Alzheimer-type and vascular dementia), schizophrenia and mood disorder.  相似文献   
66.
Abstract  Mini Mental State Examination (MMSE), Brief Psychiatric Rating Scale (BPRS) and subscales of the BPRS were performed on 73 elderly inpatients (mean age: 67.9 years; standard deviation: 7.2; range: 60–89) diagnosed with DSM-III-R chronic schizophrenia. Forty of the subjects were men and 33 were women. A significant negative correlation was observed between MMSE and the age, factor negative, factor depressive, and total score of BPRS. We believe, however, that it is relatively sufficient to screen for demented illness of schizophrenics using MMSE when considering the age and the psychiatric symptoms (especially negative or depressive symptoms). Forty-eight (66%) of the 73 patients were categorized as 'demented' by MMSE. These results suggest that the aged inpatients with schizophrenia in a hospital showed certain kinds of cognitive deficits (including senile dementia) more frequently than the general population.  相似文献   
67.
We have shown that two CNBr fragments of horse apocytochrome c, [Homoser-lactone65](1–65) and (66–104), bind to the ferric heme fragment (1–25)H to form a non-productive three-fragment complex, and that when the heme of this complex has been kept reduced for 48 h at 25°, the peptide bond between residues 65 and 66 is restored with a yield of 24% or more. We have also shown that another CNBr fragment [Homoser-lactone65](23–65), but not [Homoser-lactone65](39–65), similarly rejoins to fragment (66–104) in the presence of the ferrous heme fragment with 25% or more yield. For complex of ferro-heme fragment [Hse-lacton65](1–65)H and apofragment (66–104) of horse cytochrome c, which restores the peptide bond between residues 65 and 66 (located on the left side of the heme) (cf. Harbury, H.A. (1978) in Semisynthetic Peptides and Proteins (Offord, R.E. & DiBello, C., eds.), pp. 73–89, Academic Press, New York), Corradin & Harbury have suggested that axial ligation of methionine 80 to the heme (on the left side) is important. Consistent with their idea, fragment [Hse80](66–104) was found not to link to [Hse-lactone65](1–65) in the presence of ferro(1–25)H. Furthermore, the present studies indicate that the interaction involving residues 26 to 38 (on the right side) is also important for such a conformation which assists in the rejoining of the two apofragments. Combining these two ideas, we suggest that restoration of the peptide bond between residues 65 and 66 reflects the structural integrity of these complexes in the reduced form. Thus, the present reaction system can be used not only for chemical synthesis of [Homoser65] apocytochrome c but also to extend amino acid substitution studies of cytochrome c to residues 1 to 64.  相似文献   
68.
A series of thyrotropin-releasing hormone (TRH) analogs in which the pyroglutamic acid residue was replaced by (S)-2-oxoimidazolidine-4-carboxylic acid (Oic-OH) and the related derivatives was prepared, and the central nervous system (CNS) actions were examined. Of these, 1-benzyl-Oic-His-Pro-NH2 (2c) showed the most potent activities, which were 1.5-8 times greater than those of TRH. Moreover, the thyrotropin (TSH)-releasing activity of 2c was about 1/16 times weaker than that of TRH.  相似文献   
69.
Tetrameric concanavalin A at neutral pH dissociated into the dimer when CuCl2 was added in a concentration range comparable to protomer concentration. This effect of CuCl2 was largely suppressed when NaCl concentration was increased. Neither the conformation of the protein nor its binding activity to 4-methylumbelliferyl α-D-man-nopyranoside was affected on addition of CuCl2.  相似文献   
70.
Trichosporon beigelii Pneumonia in a Patient with Malignant Histiocytosis   总被引:1,自引:0,他引:1  
A 30-year-old previously healthy housewife presented with bilateralpulmonary infiltrates. She was treated with various antibioticsbut died with disseminated intravascular coagulation. Culturesof tracheal aspirates obtained prior to her death yielded Trichosporonbeigelii. Postmortem examination revealed T. beigelii pneumoniawith fungal dissemination in other organs. In addition, manyorgans were found to be infiltrated with atypical mononuclearcells which exhibited cytochemical properties of histiocytes.It was considered, therefore, that T. beigelii pneumonia developedon the basis of underlying malignant histiocytosis. T. beigeliiin her lung sections was fluorescently stained with rabbit antiserumto the fungus isolated from the patient. This is the first reportof Trichosporon beigelii pneumonia associated with malignanthistiocytosis.  相似文献   
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