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   242128篇
  免费   20446篇
  国内免费   14398篇
耳鼻咽喉   2177篇
儿科学   3040篇
妇产科学   4880篇
基础医学   28311篇
口腔科学   4208篇
临床医学   30865篇
内科学   39827篇
皮肤病学   2820篇
神经病学   13544篇
特种医学   8608篇
外国民族医学   96篇
外科学   26659篇
综合类   34074篇
现状与发展   48篇
一般理论   45篇
预防医学   15096篇
眼科学   6675篇
药学   24192篇
  165篇
中国医学   10913篇
肿瘤学   20729篇
  2024年   709篇
  2023年   3490篇
  2022年   8679篇
  2021年   11421篇
  2020年   8381篇
  2019年   7593篇
  2018年   7990篇
  2017年   6966篇
  2016年   6663篇
  2015年   10088篇
  2014年   12691篇
  2013年   11881篇
  2012年   17533篇
  2011年   19212篇
  2010年   11715篇
  2009年   9377篇
  2008年   12756篇
  2007年   12810篇
  2006年   12361篇
  2005年   12440篇
  2004年   8599篇
  2003年   7641篇
  2002年   6607篇
  2001年   5991篇
  2000年   6123篇
  1999年   6410篇
  1998年   3664篇
  1997年   3677篇
  1996年   2793篇
  1995年   2585篇
  1994年   2236篇
  1993年   1501篇
  1992年   2291篇
  1991年   1996篇
  1990年   1664篇
  1989年   1459篇
  1988年   1273篇
  1987年   1183篇
  1986年   947篇
  1985年   753篇
  1984年   493篇
  1983年   385篇
  1982年   226篇
  1981年   204篇
  1980年   196篇
  1979年   243篇
  1978年   142篇
  1977年   113篇
  1976年   98篇
  1974年   116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
斑点—酶联免疫吸附试验检测卡氏肺孢子虫   总被引:1,自引:0,他引:1  
应用完整的卡氏肺孢子虫包囊作抗原,以4×10^7/ml包裹点样,作斑点-酶联免疫吸附试验检测肺印片卡氏肺孢子虫包囊阳性的BALB/c小鼠血清20份,同时检测包囊阴性的小鼠血清20份,结果除一份小鼠血清IgG阴性反应外,均为阳性反应,阳性率为95%;而正常对照血清全为阴性反应。另外,检测了3份纤支镜刷检物中包囊阳性的病人血清,均为阳性反应;50例健康孕妇血清的检查,抗体阳性率为12%。  相似文献   
52.
The granulocyte colony-stimulating factor (G-CSF) has been shown to accelerate recovery from severe neutropenia and to decrease the incidence of documented infections after intensive chemotherapy in cancer patients. However, the routine prophylactic use of G-CSF is expensive. This study was conducted to determine the role of G-CSF as adjunct therapy for septicemia following neutropenia caused by chemotherapy in children with acute leukemia. Fifty consecutive episodes of septicemia were studied involving 34 episodes of Gram-negative, 7 episodes of Gram-positive, 5 episodes of polymicrobial bacterial septicemia, one episode of fungemia, and 3 episodes of disseminated fungal infection. In the first 25 episodes, G-CSF was not used (group A). For the next 16 episodes, G-CSF 200 μg per square meter per day subcutaneously was given immediately after the septicemia was documented until the absolute neutrophil count was maintained at more than 1,500 per cubic millimeter (group B). Thereafter, G-CSF at the same dose as that of group B was prophylactically used in all the children who received high-dose cytosine arablnc-side-containing regimens. Nine episodes of septicemia occurred (group C). The incidences of mortality per episode of septicemia in groups A, B, and C were 12.0% (3/25), 12.5% (2/16) and 0% (0/9), respectively. Statistically, there was no difference between the three groups overall and in pair-wise comparisons (all P > 0.5). The durations of G-CSF administration in group B ranged from 6 to 26 days with a median of 12 days and the durations of G-CSF administration in group C ranged from 10 to 23 days with a median of 19 days. With or without G-CSF, there may be no significant difference in the mortality of septicemia following neutropenia caused by chemotherapy in children with acute leukemia.  相似文献   
53.
Twenty-two infants of isolated ventricular septal defect with congestive heart failure were fed with lower-sodium content formula-Lonalac (Mead-Johnson) to study the clinical response of treatment for congestive heart failure. There were no significant changes of intake, urinary output, serum sodium, potassium and osmolality before, 2 days and 6 days after Lonalac feeding. The low sodium content formula may feed the infants with congestive heart failure in addition to the traditional anticongestive therapy.  相似文献   
54.
股骨颈骨折粗细双螺钉内固定生物力学研究   总被引:3,自引:0,他引:3  
股骨颈骨折内固定方法繁多。本文采用一粗一细加压螺纹钉,采用先进电阻应变仪方法,对股骨颈的应力分布规律在中立、外展、内收不同位置上施加50kg荷载压力.通过电阻应变计测定一耗一细两钉所承受拉、压应力优于其它内固定形式。  相似文献   
55.
Ductal adenoma of the breast   总被引:1,自引:0,他引:1  
Ductal adenoma is a recently described benign tumour of the breast that can be mistaken for carcinoma in both frozen and paraffin sections. Such a case is presented. Fortunately a mastectomy was not performed, but the patient did undergo axillary node dissection. Surgeons and pathologists should familiarize themselves with this lesion so that patients do not have to undergo unnecessary mastectomies and axillary node dissections.  相似文献   
56.
The hereditary characteristics of enzyme deficiency and dermatoglyphics in congenital color blindness (CCB) were studied. We propose that there is a linkage between the two loci on the X-chromosome determining CCB and glucose-6-phosphate dehydrogenase (G6PD), based on our study of a high incidence of G6PD deficiency in 156 male cases with CCB. The CCB gene is closely linked with that of G6PD deficiency from our pedigree investigations. The rise in the frequency of eight or more whorls, the low value of atd angle and the presenting rate of real palmar patterns of the thenar, hypothenar and I, areas presented the hereditary traits of congenital color blindness.  相似文献   
57.
58.
59.
Endothelial cell antigens recognized by xenoreactive human natural antibodies.   总被引:10,自引:0,他引:10  
Hyperacute rejection of vascularized, discordant xenografts is generally though to be initiated when natural antibodies of the recipient bind to endothelial cells of the donor organ. While rejection of such xenografts always occurs, the molecular targets of natural antibodies have not been elucidated. The aim of the experiments reported herein was to identify the molecules on porcine endothelial cells that would be recognized by human natural antibodies if a porcine organ were to be transplanted into a human (or rhesus). Toward the end, it was shown that the major components recognized by human serum on porcine endothelial cells are glycoproteins of 115kDa, 125kDa, and 135kDa (gp115/135). Reactivity with these glycoproteins was abrogated by enzymatic cleavage of N-linked oligosaccharides or of subterminal beta-D-gal residues suggesting that the determinants are located on oligosaccharides rather than on the polypeptide cores. The biological relevance of gp115/135 was suggested by experiments in which a similar series of components was shown to be recognized by rhesus natural antibodies and by the absorption of such antibodies by perfusion of porcine kidneys. The gp115/135 antigens were present on porcine platelets but not porcine RBC or lymphocytes. Nevertheless, purified RBC and lymphocytes absorbed human anti-gp115/135, suggesting that human natural antibodies recognize the same or crossreactive carbohydrate determinants expressed on the surface of a variety of cells.  相似文献   
60.
Monoamine oxidase (MAO) A and B play an important role in regulating levels of biogenic amines. MAO A and B cDNAs have been cloned and the deduced amino acids share 73% sequence identity. The genes for MAOA and B are comprised of 15 exons interspersed by 14 introns, span at least 60 kb and exhibit identical exon-intron organization. These findings suggest that the MAOA and MAOB genes are derived from the duplication of a common ancestral gene. The core promoter region of MAOA is comprised of two 90 bp repeats, each of which contains two Spl elements and lacks a TATA box. The MAOB core promoter region contains two sets of overlapping Spl sites which flank a CACCC element all upstream of a TATA box. The different organization of the MAOA and MAOB promoters may underlie their different cell and tissue specific expression.  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