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   178篇
  免费   8篇
儿科学   8篇
基础医学   24篇
口腔科学   3篇
临床医学   12篇
内科学   40篇
皮肤病学   19篇
神经病学   4篇
特种医学   30篇
外科学   17篇
综合类   4篇
预防医学   12篇
药学   5篇
中国医学   2篇
肿瘤学   6篇
  2022年   1篇
  2021年   1篇
  2019年   1篇
  2018年   5篇
  2017年   3篇
  2016年   1篇
  2015年   2篇
  2014年   5篇
  2013年   4篇
  2012年   3篇
  2011年   7篇
  2010年   10篇
  2009年   4篇
  2008年   5篇
  2007年   6篇
  2006年   4篇
  2005年   3篇
  2004年   2篇
  2003年   2篇
  2002年   1篇
  2001年   1篇
  2000年   1篇
  1998年   5篇
  1997年   7篇
  1996年   5篇
  1995年   6篇
  1994年   7篇
  1993年   3篇
  1992年   5篇
  1991年   1篇
  1990年   4篇
  1989年   5篇
  1988年   7篇
  1987年   5篇
  1986年   9篇
  1985年   9篇
  1984年   4篇
  1983年   4篇
  1982年   5篇
  1981年   5篇
  1980年   3篇
  1979年   4篇
  1978年   4篇
  1977年   1篇
  1976年   2篇
  1975年   2篇
  1974年   1篇
  1961年   1篇
排序方式: 共有186条查询结果,搜索用时 8 毫秒
71.
72.
73.
A 29-yr-old white female has suffered from recurrent venous thromboses over the last 12 yr. Plasma antithrombin III (AT-III) levels were 48% of normal by immunoelectrophoresis and 56% by chromogenic assay. Three of four siblings and the father had similar AT-III levels without associated venous thromboses. Heparin-Sepharose chromatography demonstrated normal behavior of the patient's AT-III. Her purified AT- III could not be distinguished from AT-III purified from a normal control either by SDS polyacrylamide gel electrophoresis or by crossed immunoelectrophoresis, and the heparin cofactor activity and the progressive antithrombin activity of both AT-III samples were identical. Turnover studies were made in the patient using her own purified AT-III labeled with 131I, (*I). The results did not differ significantly from studies made with autologous *I-AT-III in two normal control women. Her fractional breakdown rate of 0.54 total plasma AT- III per day compared with 0.45 and 0.52 in the controls. These studies indicate that the patient synthesizes a normal AT-III molecule at half normal rates.  相似文献   
74.
Harriss  EB; Hoelzer  D 《Blood》1978,51(2):221-227
In the experimental rat leukemia, L5222, the decrease of normal in vitro colony-forming cells (CFU-C) after chemotherapy with daunomycin is much less than in nonleukemic controls. The leukemia is therefore used here to test the hypothesis that in leukemia the CFU-C are expelled from the active cell cycle to a resting state and are thereby less sensitive to cycle-dependent chemotherapeutic agents. The L5222 leukemia has the advantage that the leukemic blast cells do not form colonies in agar culture so that normal CFU-C can be assessed under leukemic conditions. To compare the proportions of CFU-C in the S-phase in normal and leukemic rats, two S-phase-specific agents, 3H-thymidine and hydroxyurea, were used to kill proliferating bone marrow cells. Following treatment with 3H-thymidine in vitro, about 41% of the CFU-C were killed in normal and about 25% in leukemic bone marrow. Hydroxyurea administered in vivo resulted in the death of about 33% and 26%, respectively. The results indicate that fewer normal CFU-C are in S-phase in the L5222 leukemia, which might help to explain how enough normal stem cells survive chemotherapy to regenerate the bone marrow.  相似文献   
75.
Ratcliffe  DR; Michl  J; Cramer  EB 《Blood》1993,82(5):1639-1646
Neutrophils appear to form the first line of defense against influenza virus, yet it is unclear how these leukocytes recognize influenza- infected cells. While demonstrating that neutrophils adhere specifically to the sialic acid-binding site on the hemagglutinin molecule (HA) on the surface of influenza-infected (WSN[H1N1]) epithelial cells and not to other viral or epithelial cell antigens, it was observed that human neutrophils do not recognize immune complexes formed with influenza virus. Intact antibodies (mouse monoclonal antibodies [MoAbs] IgG1 and IgG2b, human immune heat-inactivated serum [predominantly IgG1], and IgG purified from human immune serum) that block the sialic acid-binding site on HA significantly reduced (> 80%) neutrophil adherence to influenza-infected epithelial cells. Binding and phagocytosis of free influenza virions and neutrophil agglutination by influenza virus were completely prevented by these antibodies. Intact and F(ab')2 fragments of mouse MoAbs to other viral epitopes caused increased neutrophil adherence to infected cells. This binding was eliminated by F(ab'2) fragments of MoAbs against the sialic acid- binding site on HA, but not by saturating amounts of MoAbs, which block the neutrophil Fc receptors. Thus, it appears that human neutrophils show little ability to bind via their Fc receptors to the immune complexes formed with antibody and either influenza-infected epithelial cells or the free virion. These findings are in contrast to the general dogma, and are the first example of antibody opsonization reducing, rather than enhancing, neutrophil binding and phagocytosis of a pathogen.  相似文献   
76.
Neuroscience and Behavioral Physiology - Neuron activity in the amygdaloid complex was studied in baseline conditions and on exposure to electrical stimulation of the prefrontal cortex in intact...  相似文献   
77.
78.

Background

Infectivity of herbivores with Trichostrongylus nematodes is widespread in many countries, having a major economic impact on breeding, survivability, and productivity of domestic livestock. This study was carried out on Trichostrongylus species isolated from domestic livestock in order to develop an easy-to-perform method for species identification.

Methods

Trichostrongylus isolates were collected from sheep, goat, cattle, and buffaloes in Khuzestan Province, southwest Iran. Primary species identification was carried out based on morphological characterization of male worms. PCR amplification of ITS2-rDNA region was performed on genomic DNA and the products were sequenced. Phylogenetic analysis of the nucleotide sequence data was conducted employing Bayesian Inference approach. Consequently, a restriction fragment length polymorphism (RFLP) profile was designed to differentiate Trichostrongylus species.

Results

A consensus sequence of 238 nucleotides was deposited in the GenBank for Iranian isolates of Trichostrongylus species including T. colubriformis, T. capricola, T. probolurus and T. vitrinus. The designated RFLP using restriction enzyme TasI could readily differentiate among species having different ITS2 sequence. The molecular analysis was in concordance with morphological findings.

Conclusion

Phylogenetic analysis indicated a close relationship among the sequences obtained in this study and reference sequence of relevant species. ITS2-RFLP with TasI is recommended for molecular differentiation of common Trichostrongylus species.  相似文献   
79.
Aim: To test the validity and reliability of a Swedish version of the Non‐Communicating Children’s Pain Checklist – Postoperative Version (NCCPC‐PV). Methods: Thirty‐two consecutive children/adolescents (2–20 years of age) with cognitive impairment and no verbal communication from four habilitation centres were admitted to the study. Each child’s behaviour was observed by a parent or a caregiver and by a physiotherapist in two calm and two painful situations within the child’s everyday life. The raters independently assessed and graded the child’s behaviour during 5 min according to the translated Swedish version of the NCCPC‐PV. The intrarater and interrater reliability were determined, and the construct validity was examined. Results: The results from 202 assessments showed that the construct validity was good: children’s behavioural signs differed significantly between situations of pain and situations of calm (p < 0.001). Repeated assessments showed poor agreement both within and between raters [intraclass correlation coefficient (ICC) 0.51–0.65]. The agreement for pain was good (ICC 0.83). Conclusion: The Swedish version of the NCCPC‐PV can be used for pain assessment in children with cognitive impairments who lack verbal communication. Aspects of reliability need to be further analysed.  相似文献   
80.
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