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   11757篇
  免费   539篇
  国内免费   54篇
耳鼻咽喉   122篇
儿科学   207篇
妇产科学   64篇
基础医学   1143篇
口腔科学   215篇
临床医学   737篇
内科学   3252篇
皮肤病学   383篇
神经病学   806篇
特种医学   411篇
外科学   2224篇
综合类   64篇
预防医学   246篇
眼科学   163篇
药学   749篇
中国医学   10篇
肿瘤学   1554篇
  2023年   72篇
  2022年   155篇
  2021年   244篇
  2020年   127篇
  2019年   197篇
  2018年   227篇
  2017年   178篇
  2016年   238篇
  2015年   255篇
  2014年   304篇
  2013年   391篇
  2012年   681篇
  2011年   681篇
  2010年   409篇
  2009年   364篇
  2008年   609篇
  2007年   590篇
  2006年   635篇
  2005年   684篇
  2004年   689篇
  2003年   667篇
  2002年   674篇
  2001年   249篇
  2000年   256篇
  1999年   238篇
  1998年   189篇
  1997年   157篇
  1996年   145篇
  1995年   124篇
  1994年   150篇
  1993年   90篇
  1992年   134篇
  1991年   139篇
  1990年   143篇
  1989年   145篇
  1988年   128篇
  1987年   108篇
  1986年   127篇
  1985年   98篇
  1984年   73篇
  1983年   68篇
  1982年   48篇
  1981年   32篇
  1979年   42篇
  1978年   31篇
  1977年   51篇
  1975年   30篇
  1972年   32篇
  1971年   32篇
  1970年   32篇
排序方式: 共有10000条查询结果,搜索用时 26 毫秒
1.
OBJECTIVES: To reveal the frequency and the clinical characteristics of dystrophic calcification that occurs in children with juvenile dermatomyositis, multi-center analysis was constructed. METHOD: Fifty children with JDM were enrolled, and 14 of them (28.0%) were complicated with calcinosis. Clinical symptoms and laboratory tests at onset, initial therapy and disease course were compared in children with and without calcinosis. RESULTS: The mean age of the onset of calcinosis was 4.78 +/- 3.33 years, and it was younger than those of children without calcinosis (8.66 +/- 3.85 years) (P = 0.0017). No differences of clinical manifestation except Gower's sign were observed. The frequency of positive anti-nuclear antibody was 7.1% in children with calcinosis and 52.9% without calcinosis (P = 0.0112). The initial therapy of methylprednisolon pulses gave no effects on prognosis of calcium deposition. The calcinosis appeared in 1.56 +/- 1.91 year after the onset of the disease. The various types of calcium deposition including large tumorous clumps, subcutaneous plaques or nodules, sheet-type calcification were deserved. They appeared over knee joints (64.3%), elbow joint (64.3%), and hip processes (50.0%). Calcinosis affecting the subcutaneous tissues frequently resulted in painful superficial ulceration of the overlying skin (42.9%), local infection (50.0%), and limitation of joint movement (14.3%). Although aluminum phosphate was effective in 2 children among 7, no other effective treatment was recommended. In 5 cases, surgical removal of tumorous clumps was operated. Thus, juvenile dermatomyositis is frequently complicated with calcinosis. This type of calcinosis was found to be unlikely to resolve completely, and resulted in severe disability in children.  相似文献   
2.
The effects of spironolactone (5% SYC-201G, a preparation developed for clinical use in acne vulgaris by Searle Yakuhin K.K.), which is known to have antiandrogenic effects by competitively inhibiting dihydrotestosterone at androgen receptor sites, was topically applied to the androgen stimulated sebaceous glands of adult female golden hamsters. Androgen stimulation, induced by intramuscular injection of testosterone propionate (TP) every other day over a two week period, resulted in a 2.5 to 2.7 time increase in the size of the sebaceous glands of the hamster pinna. Once-daily treatment with 5% SYC-201G or matching placebo was applied to androgen-stimulated hamsters on one pinna only during the same period as TP injection. Comparison between the treated and untreated sides revealed a significant suppression in the sebaceous gland size (p<0.05) by 5% SYC-201G; no such effect was observed with placebo. The difference in the suppression rate of the sebaceous gland size between 5% SYC-201G (23%) and matching placebo (–4.7%) was significant (p<0.01).  相似文献   
3.
We studied functional and immunohistochemical characteristics of cultured rat microglia. Unstimulated microglia did not proliferate. Microglia stimulated with LCM (L929 conditioned medium: colony stimulating factor-1) had proliferative activity and increased acid phosphatase activity. LPS (lipopolysaccharide) and IFN gamma (interferon-gamma) but did not affect proliferative activity. Immunohistochemically, RCA-1 lectin and GS-1 lectin, which react to beta-D-galactose and alpha-D-galactose respectively, strongly reacted to the cytoplasm and membrane of unstimulated microglia. After stimulation with LCM, microglia elongated processes and decreased response to these lectins. On the other hand, microglia stimulated with LCM showed increased reactivity to monoclonal antibody of vimentin. Microglia stimulated with LPS had round shape and had response to these lectins and vimentin. Microglia stimulated with IFN gamma had adhesive activity and weakly stained with these lectins but not with vimentin. ED-1 (monoclonal antibody of rat monocytes/macrophages) reacted to unstimulated and stimulated microglia. In flow cytometry, unstimulated microglia expressed OX-18 (MHC class I) and W3/25 (CD4) antigen. After stimulation with IFN gamma, microglia were induced to express these antigens. CD4 antigen is a marker of helper/inducer T cells and thought to be a receptor of HIV. The results that microglia had CD4 antigen which was further induced with IFN gamma are important to investigate infection of the CNS with HIV. OX-6 (Ia) antigen was induced with IFN gamma. This indicates that the microglia plays a central role in the CNS immune reaction. These characteristics of cultured rat microglia provide useful informations to investigate the pathogenesis of the CNS disorders.  相似文献   
4.
5.
AIMS: A rare case of the insulin autoimmune syndrome (IAS) accompanied by insulin receptor anomaly is reported. METHODS: Antibodies to insulin and insulin receptor were determined in the patient with severe hypoglycaemia before and after the treatment with prednisolone. RESULTS: Titers of antibody to insulin and insulin receptors were 73.0% and 41.5%, respectively. Drug-induced lymphocyte stimulation tests were all negative for the suspicious drugs. Her HLA-DR was DRB1*0403/04051. Following steroid therapy, the formation of antibodies was suppressed and alleviated her symptoms. Scatchard analysis yielded findings specific to polyclonal antibodies. CONCLUSIONS: The changes in autoantibodies resulted in alleviation of the hypoglycemic symptoms as a result of steroid therapy.  相似文献   
6.
Pseudomonas aeruginosa is one of the most important pathogens in patients with chronic airway conditions, such as cystic fibrosis and diffuse panbronchiolitis. Type III secretion system-mediated virulence factors contribute to the lung damage in chronic P. aeruginosa infection. The effects of the anti-PcrV immunoglobulin (Ig)G, which blocks the type III secretion system, were evaluated in a mouse model of chronic P. aeruginosa infection. On bacteriological examination, anti-PcrV IgG showed no bactericidal effects. On bronchoalveolar lavage fluid (BALF) analysis, total cell number and neutrophil ratios in the anti-PcrV IgG-treated groups were lower than those in the control group. In addition, macrophage inflammatory protein-2, tumour necrosis factor-alpha, and interleukin-beta concentrations in BALF were lower in the anti-PcrV IgG-treated groups when compared with controls. Plasma anti-PcrV IgG titre was elevated after administration of anti-PcrV IgG. Although plasma titre decreased gradually, a significant concentration was maintained during the experimental period. These data suggest that anti-PcrV immunoglobulin G reduces the inflammatory reaction caused by chronic Pseudomonas aeruginosa respiratory infection and may be useful in treating respiratory diseases.  相似文献   
7.
8.
1. We previously reported that volatile anaesthetics produce incidences of a transient opisthotonus in mice, a sign of CNS stimulation. This study was performed to investigate mechanisms by which enflurane-induced opisthotonus (EIO) occurs. 2. The effects of pretreatment of N-methyl-d-aspartate (NMDA) antagonists dizocilpine (MK-801; DIZ) and ketamine (KET), GABAA antagonists picrotoxin (PIC), pentylenetetrazol (PTZ) and glycine antagonist strychnine (STR) on the incidence of EIO were determined. Prior to exposure to 2.0% enflurane in air, male ddN mice were given intraperitoneal injections of 0.2 mL saline (control), 0.5–5.0 mg/kg DIZ, 20–80 mg/kg KET, 2.9 mg/kg PIC, 40.0 mg/kg PTZ and 0.75 mg/kg STR. After the injection, the behavioural state of the mice was observed for 20 min (the pre-enflurane period). During the exposure to enflurane the time for immobilization, that is, anaesthetic induction time (IT), and the incidence of EIO were measured. 3. Dizocilpine (1.0–5.0 mg/kg) and KET (80 mg/kg) significantly (P<0.01) reduced both the incidence of EIO and IT in a dose-dependent manner. During the pre-enflurane period DIZ produced incidences (5–40%) of transient seizures in a dose-dependent manner, while KET did not induce them at all. The two GABAa antagonists had no detectable effect on the EIO. Strychnine significantly enhanced the EIO. These CNS stimulants resulted in a 3–10% incidence of transient seizure and/or opisthotonus during the pre-enflurane period, but there was no correlation between DIZ-induced seizure and EIO. 4. These results suggest that the EIO is mediated by the NMDA and the STR-sensitive glycine receptors, but not the GABAA receptor. We speculate that DIZ acts on the NMDA-receptor and/or disrupts the balance between the inhibitory and the excitatory systems.  相似文献   
9.
Ruptured aneurysm of the sinus of Valsalva is a rare cardiac lesion. A ruptured aneurysm of the sinus of Valsalva in the right ventricle of a 64-year-old man was successfully repaired. The patient was admitted to the hospital with high fever and chest oppression. Diagnosis was made by two dimensional echocardiography, cardiac catheterization, and cardiac angiography. An aortotomy, main pulmonary arteriotomy, and right ventriculotomy were performed. There was no VSD, and the aneurysm originated from the right coronary sinus, rupturing into the right ventricle inlet portion. The ruptured aneurysm of the sinus of Valsalva was closed with a Dacron patch from inside the aorta. He is doing well after surgery. There was no heart murmur. CTR decreased and pulmonary blood flow fell to a normal value. As far as we know, this patient is the second oldest patient in Japan with surgical repair.  相似文献   
10.
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