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   10102篇
  免费   460篇
  国内免费   30篇
耳鼻咽喉   154篇
儿科学   143篇
妇产科学   112篇
基础医学   1003篇
口腔科学   327篇
临床医学   580篇
内科学   2269篇
皮肤病学   350篇
神经病学   820篇
特种医学   408篇
外科学   1571篇
综合类   40篇
一般理论   1篇
预防医学   364篇
眼科学   135篇
药学   903篇
中国医学   11篇
肿瘤学   1401篇
  2023年   62篇
  2022年   112篇
  2021年   170篇
  2020年   109篇
  2019年   146篇
  2018年   193篇
  2017年   162篇
  2016年   162篇
  2015年   176篇
  2014年   233篇
  2013年   254篇
  2012年   424篇
  2011年   477篇
  2010年   265篇
  2009年   212篇
  2008年   413篇
  2007年   422篇
  2006年   444篇
  2005年   447篇
  2004年   427篇
  2003年   384篇
  2002年   399篇
  2001年   408篇
  2000年   401篇
  1999年   381篇
  1998年   129篇
  1997年   96篇
  1996年   93篇
  1995年   80篇
  1994年   73篇
  1993年   56篇
  1992年   255篇
  1991年   242篇
  1990年   248篇
  1989年   243篇
  1988年   214篇
  1987年   203篇
  1986年   164篇
  1985年   178篇
  1984年   126篇
  1983年   107篇
  1982年   45篇
  1979年   87篇
  1978年   57篇
  1977年   54篇
  1974年   53篇
  1971年   49篇
  1969年   46篇
  1967年   46篇
  1966年   43篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
In order to study the relationship between personality and the development of diabetic retinopathy in patients with diabetes mellitus, diabetics with retinopathy (severe group) and sex-, age-, and duration-matched diabetics without complications were tested by psychological tests, and interviewed. The result of the Yatabe-Guilford personality test (Y-G) and Spielberger's State and Trait Anxiety Inventory revealed that subjects were emotionally and socially stable and well-adjusted types and less anxious in the severe group than in the mild group. The interview findings reveal that the severe group had neglected the medical treatment and the diet therapy for significantly longer periods of time and the incidence of a childhood parental separation was significantly higher in the severe group than in the mild group. Discussion focuses on the severe diabetics' coping behavior which is characterized by the neglect of medical treatment and diet therapy for extended periods of time, which in turn resulted in diabetic retinopathy and other complications. Such coping behavior is shown to be equivalent to that found in the alexithymic behavioral syndrome.  相似文献   
42.
Leukocyte adhesion to vascular endothelial cells is an essential step in the development of inflammatory diseases. We have searched for inhibitors of leukocyte-endothelial cell adhesion that could be used as anti-inflammatory drugs and found that bruceine B (0.2 g/ml; 0.44 M) inhibited human neutrophil or T cell adhesion to tumor necrosis factor- (TNF) stimulated human umbilical vein endothelial cells (HUVEC). The inhibition of neutrophil adhesion to TNF-stimulated HUVEC by bruceine B was not derived from cytotoxic effects, as determined by measurement of the level of lactate dehydrogenase (LDH) activity in conditioned medium. The effect of bruceine B on neutrophil adhesion to HUVEC was not seen when the neutrophils were preincubated with bruceine B. However, inhibitory effects were evident when the HUVEC were preincubated with bruceine B. Bruceine B also inhibited neutrophil adhesion to lipopolysaccharide-stimulated HUVEC and T cell adhesion to TNF-stimulated HUVEC. These findings suggest that bruceine B may have anti-inflammatory activity.  相似文献   
43.
High-performance liquid chromatography was successfully used to separate hemagglutination-inhibiting immunoglobulin M (IgM) rubella virus antibody from IgG rubella virus antibody in human serum. The fractionation by high-performance liquid chromatography was as effective as sucrose density gradient centrifugation in separating IgM antibody from IgG antibody.  相似文献   
44.
This study was designed to explore whether it was possible to evaluate the severity of VSD, PDA, and ASD by measuring brain natriuretic peptide (BNP) levels. We also investigated normal BNP levels in children to provide a baseline for our study. We measured BNP levels in 253 normal children, including 11 normal neonates, and in 91 VSD patients, 29 PDA patients, and 34 ASD patients. BNP levels showed no age-related differences in normal children (the mean value: 5.3 +/- 3.8 pg/ml). In the healthy neonates, BNP levels rose from 10.4 +/- 11.9 pg/ml in cord blood to 118.8 +/- 83.2 pg/ml on day 0, then fell to 15.3 +/- 7.8 pg/ml by day 7. In VSD and PDA patients, BNP levels correlated significantly with Qp/Qs, LVEDV, and peak RVP/LVP. In ASD patients, BNP levels correlated with Qp/Qs and RVEDV. Especially, in VSD patients, as an index corresponding to 1.5-2.0 of the Qp/Qs ratio, BNP levels of 20-35 pg/ml were found to be best with regard to both sensitivity and specificity. In the healthy neonates, BNP levels changed rapidly after birth. In VSD, PDA, and ASD patients, BNP levels were well-correlated with the severity of the disease. Especially, in VSD patients, it that appears BNP levels may be useful in evaluating surgical indications, with 20-35 pg/ml levels being the appropriate cut-off value.  相似文献   
45.
46.
Malignant salivary gland tumors in children are very rare. This report describes the autopsy of a child with parotid gland cancer. The patient, a 10 month old girl, was admitted to the Nagoya First Red Cross Hospital with facial nerve palsy. lncisional biopsy of a post-auricular tumor was performed, and undifferentiated carcinoma was diagnosed. The patient died 6 months later of respiratory failure due to pulmonary lymphangitis carcinomatosis. Light and electron microscopic and immunohistochemical examinations of the tumor tissue were performed. The tumor cells were arranged in a medullary, sheet-like manner. Keratinization or mucus lakes were not observed. PAS-alcian blue staining demonstrated intracytoplasmic mucus as granules, and also small intercellular droplets of mucus that might otherwise have been unnoticed. Ultrastructurally, some of the tumor cells had tonofilament-like keratin filaments, and also small hollow spaces bounded by microvilli and containing secretory particles. These were stained by antisera against CEA and keratin. These findings are suggestive of differentiation to mucoepider-moid carcinoma. We also review and discuss malignant salivary tumors of epithelial origin in children. Acta Pathol Jpn 40: 149–152, 1990.  相似文献   
47.
Severe inflammatory responses after major surgeries, trauma, and infection develop multiple organ dysfunction. In the mechanisms of the pathogenesis of these responses, activated neutrophils are thought to be important in terms of their ability to produce various kinds of proteinases, which can degrade various proteins constructing human tissues. Among their proteinases, neutrophil elastase is the strongest serine proteinase secreted from activated neutrophils. Thus, we examined in this study the inhibitory effect and therapeutic efficacy of newly produced recombinant human Kunitz-type proteinase inhibitor (R-020), which coded the second domain of human urinary trypsin inhibitor. R-020 was effective in significantly improving the survival rate after induction of the rat lethal peritonitis model (cecal ligation and punctureinduced septic shock model). We suggest that various serine proteinases are implicated in the pathogenesis of neutrophil-related multiple organ failure and that recombinant human Kunitz-type proteinase inhibitor might be effective in the treatment of these kinds of organ dysfunction.  相似文献   
48.
In this study, the structure of the α1-acid glycoprotein (AGP), or orosomucoid (ORM), gene was investigated in a Ghanaian mother and her child, who shared an unusual variant, ORM1 S2(C), found by isoelectric focusing. Three remarkable changes of nucleotide sequence were observed: (1) The two ORM1 alleles, ORM1 * S and ORM1 * S2(C), had the AGP2 gene-specific sequence at one and three regions, respectively, in exon 5 to intron 5. The variant allele originating from ORM1 * S was characterized by a G-to-A transition, resulting in an amino acid change from valine to methionine, which is also detected in ORM1 F2, a form that is common in Europeans. (2) The AGP2 gene of the child, inherited from the father, was duplicated, as revealed by long-range polymerase chain reaction. (3) Three new mutations were observed in two exons of the AGP2 genes of the mother and child. All of these novel genomic rearrangements, which were not observed in Japanese subjects, may have arisen through point mutation, gene conversion, and unequal crossover events. It is likely that the rearrangement of the AGP gene has often occurred in Africans. Received: June 15, 2001 / Accepted: July 10, 2001  相似文献   
49.
AIM: The aim of this study was to analyse the immunopathological mechanisms of vasculo-Beh?et disease, which were also compared to cases of Takayasu's arteritis and inflammatory aneurysm to evaluate differences in inflammatory mechanisms. METHOD AND RESULTS: We reviewed six cases of vasculo-Beh?et disease, four of Takayasu's arteritis and seven inflammatory aneurysms which underwent surgical repair. Immunohistochemical studies were performed on paraffin-embedded tissue using a labelled streptavidin-biotin method, as was in-situ hybridization for Epstein-Barr virus. Microscopically, neutrophils and lymphocytes accumulated around the vasa vasorum. Neutrophils were prominent as compared to Takayasu's arteritis and inflammatory aneurysm. Elastic fibres were not severely destroyed. Endothelial cells (ECs) of most vasa vasorum expressed HLA-DR. The number of vasa vasorum around which inflammatory infiltrating cells were observed in vasculo-Beh?et disease was significantly greater than in inflammatory aneurysms and Takayasu's arteritis (P < 0.001). The cytokines IL-1alpha, TNF-beta and IFN-gamma were expressed in neutrophils and lymphocytes which were distributed around vasa vasorum, as well as neutrophils adherent to HLA-DR positive ECs. CONCLUSION: Our results suggest that vasculo-Beh?et disease should be classified as a neutrophilic vasculitis targeting the vasa vasorum. Aneurysm formation may be related to degeneration of arterial wall caused by inflammation of the vasa vasorum.  相似文献   
50.
PURPOSE: To enable international comparison of prevalence in asthma, we translated and evaluated ECRHS Questionnaire, which is introduced in GINA. Considering COPD prevalence in elder people, we added two questions to the ECRHS Questionnaire. METHOD: The Japanese edition of ECRHS Questionnaire was responded by 366 patients who were diagnosed asthma without COPD, 61 patients who were diagnosed COPD without asthma, and 137 healthy persons who were not diagnosed asthma or COPD. We analyzed the answers of the each group and evaluated the validity of the questionnaire to use for the nation-wide prevalence study of adult asthma in future. RESULTS: The question of 'Wheezing at any time in the last 12 months' had the highest Youden's index and validity to pick up asthma patients. The questions of 'Waking up with a feeling of tightness in chest at any time in the last 12 months' and 'Waking up by an attack of shortness of breath at any time in the last 12 month' had the highest specificity to pick up asthma patients. Most of the questions which were related asthma were able to be answered by asthma patients properly, but some questions were improperly answered by patients and healthy persons in elderly. The results in this study showed the less recognition of their diseases in elderly patients than younger patients and the limitation of the study with written questionnaire for elderly people. Not a few COPD patients complained wheezing or whistling in the chests as same as asthma patients in this study. CONCLUSION: We concluded that we had almost enough reliability in the Japanese edition of the ECRHS questionnaire for screening survey of asthma prevalence in Japan.  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