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   247篇
  免费   5篇
儿科学   24篇
妇产科学   3篇
基础医学   32篇
口腔科学   1篇
临床医学   37篇
内科学   60篇
皮肤病学   11篇
神经病学   14篇
外科学   32篇
综合类   2篇
预防医学   2篇
眼科学   1篇
药学   24篇
肿瘤学   9篇
  2017年   2篇
  2016年   4篇
  2015年   3篇
  2014年   4篇
  2013年   2篇
  2012年   4篇
  2011年   2篇
  2010年   7篇
  2009年   7篇
  2008年   5篇
  2007年   6篇
  2006年   8篇
  2005年   8篇
  2004年   5篇
  2003年   5篇
  2002年   5篇
  2001年   2篇
  2000年   1篇
  1999年   4篇
  1998年   21篇
  1997年   24篇
  1996年   22篇
  1995年   14篇
  1994年   11篇
  1993年   11篇
  1992年   4篇
  1991年   3篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   3篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1980年   4篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1969年   1篇
  1959年   2篇
  1958年   4篇
  1957年   9篇
  1956年   4篇
  1955年   7篇
  1954年   6篇
排序方式: 共有252条查询结果,搜索用时 234 毫秒
21.
22.
Summary. Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal disorder with a deficiency of glycosyl-phosphatidylinositol (GPI) anchored proteins. Homologous restriction factor 20KD (HRF20, CD59) is a GPI-anchored and major complement-regulatory protein which plays a key role in the haemolytic mechanism of PNH. We examined the differentiation stage at which the PNH abnormality occurs, by means of flow cytometric analysis of HRF20 expression. Non-phagocytic mononuclear marrow cells were labelled with anti-HRF20 monoclonal antibody and sorted into either HRF20-negative or -positive fractions. The sorted cells were cultured in methylcellulose and their progeny in the colonies or bursts were analysed for HRF20 expression. All colonies and bursts from HRF20-negative fractions remained negative, whereas those from HRF20-positive fractions were either positive or negative. The possibility of a sorting error was excluded, because the secondary colonies from the HRF20 positive primary colonies consisted of both positive and negative progeny. These results suggest that there are several stages during differentiation from early progenitors to mature cells, at which the PNH abnormality becomes manifest.  相似文献   
23.
24.
Abstract: Two patients with pneumatosis cystoides intestinalis (PCI) successfully treated with hyperbaric oxygen are described, The first patient was a 52-year-old male who presented with bloody stools and was diagnosed as having primary PCI. The second was a 61-year-old male whose occupation entailed prolonged exposure to trichloroethylene. Following hyperbaric oxygen therapy, the colonic gas cysts completely disappeared in both patients, and there has been no evidence of recurrence. The relevant literature from 1980 to 1992 is reviewed, and hyperbaric oxygen therapy for PCI is discussed in detail. The data accumulated thus far suggest that hyperbaric oxygen is superior to high-flow oxygen breathing in PCI therapy.  相似文献   
25.
Patients with idiopathic acquired sideroblastic anaemia (IASA) usually show macrocytic or normocytic anaemia and increased free erythrocyte protoporphyrin (FEP). The mean cell haemoglobin concentration is normal or slightly low. Here we report a pyridoxine-responsive IASA patient with microcytic and hypochromic anaemia and low FEL level; these features are usually seen in cases of hereditary sideroblastic anaemia. Microcytosis increased during therapy.
There may be a subgroup of IASA with microcytic and hypochromic anaemia, low normal FEP and some response to pyridoxine like hereditary sideroblastic anaemia.  相似文献   
26.
MPB70 and MPB83 are homologous cross-reactive secreted mycobacterial proteins with very limited species distribution. The expression of these two proteins was compared between several substrains of Mycobacterium bovis BCG, virulent M. bovis and Mycobacterium tuberculosis H37Rv. A polyclonal antibody specific for MPB70 in Western blotting, and a monoclonal antibody, MBS43, found to be specific for MPB83 in ELISA and Western blotting, were used for the comparison. The previously established pattern of high- and low-producing substrains of BCG for MPB70 is only partially applicable for MPB83. MPB70 low-producing strains are also MPB83 low-producing, but the expression of MPB83 is much more variable than the expression of MPB70 in the MPB70 high-producing strains. Purified MPB83 (23 kDa) was found to be glycosylated. A band in SDS-PAGE at 1–2 kDa lower than that of purified MPB83 may represent unglycosylated MPB83. Furthermore, it was confirmed that purified MPB70 (22 kDa) is unglycosylated. There is cross-reactive antigen at 26 kDa. The MPB83 related antigen at 26 kDa was found to be the most abundant. These findings indicate greater heterogeneity between different substrains of BCG than previously realized. Virulent M. bovis produce and secrete large amounts of MPB70 and MPB83 while both these proteins occur in a far lower concentration in M. tuberculosis  相似文献   
27.
Serum levels of the tissue inhibitor of metalloproteinases-1 (TIMP-1) were measured in 268 patients with liver diseases by means of a one-step sandwich enzyme immunoassay. In the cases of acute hepatitis, chronic active hepatitis (CAH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC), the levels of TIMP-1 were higher than those of the control group. Tissue inhibitor of metalloproteinases-1 levels correlated with type III procollagen peptide and with type IV collagen, indicating TIMP-1 as a useful marker for hepatic fibrosis. Levels of TIMP-1 also correlated with aspartate aminotransserase and alanine aminotransferase levels and showed the highest levels in acute hepatitis. Thus, TIMP-1 might also reflect hepatic inflammation. Serum levels of α-fetoprotein and TIMP-1 had a significant positive correlation in patients with HCC. A cut-off level of TIMP-1 between LC and HCC was set at 440 ng/mL, having a low sensitivity and a high specificity. These results suggest the usefulness of TIMP-1 as a tumour marker in cases of HCC where α-fetoprotein levels are not elevated.  相似文献   
28.
29.
Aggressive angiomyxoma (AAM) is a rare mesenchymal benign tumor that preferentially involves the pelvic and perineal regions in relatively young females. We report here a rare case of AAM presenting as a retrovesical tumor in a male patient. A 59-year-old man undergoing abdominal ultrasound examination because of benign prostatic hyperplasia was found to have a retrovesical mass. Computed tomography and magnetic resonance imaging of the pelvis showed the retrovesical tumor to be 7.4 x 6.7 cm. The tumor was resected, and diagnosed histopathologically as AAM. The patient showed no recurrence 26 months after resection. Although the majority of retrovesical tumors are considered to be sarcoma or neurogenic tumor, AAM should also be recognized as a differential diagnosis.  相似文献   
30.
In mammals, a master circadian oscillator is known to be located in the suprachiasmatic nucleus (SCN) of the hypothalamus. We examined the function of SCN neurons involved in the mechanism of circadian rhythm of water intake by lesioning them with an immunotoxin, anti-vasoactive intestinal polypeptide (VIP) antibody-ricin A conjugate. We found that the immunotoxin had a specific lethal effect on cultured PC12h cells when VIP was added to the medium. When the conjugate was infused into the third cerebral ventricle of rats above the SCN, two specific types of selective lesions of neurons were observed in the SCN: selective lesions of neurons containing arginine vasopressin (AVP) (AVP-neurons), and selective lesions of neurons containing VIP (VIP neurons). The former lesions caused disappearance of the circadian rhythm of drinking behavior, whereas the latter lesions did not affect the rhythm of water intake under constant dim lighting. Lesions that did not selectively affect one of these neurochemically identified SCN cell populations were also observed after the infusion of the conjugate or normal rabbit serum immunoglobulin G-ricin A chain conjugate. If these nonspecific lesions included entire region of the SCN, the circadian rhythm of water intake was abolished. These findings suggest that SCN neurons bearing VIP receptors such as AVP neurons, but not VIP neurons, may be involved in the mechanism of the circadian rhythm of water intake. Copyright © 1996 Elsevier Science Inc.  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