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   859篇
  免费   95篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   29篇
妇产科学   26篇
基础医学   110篇
口腔科学   51篇
临床医学   138篇
内科学   183篇
皮肤病学   9篇
神经病学   77篇
特种医学   40篇
外科学   80篇
综合类   30篇
一般理论   1篇
预防医学   80篇
眼科学   32篇
药学   34篇
中国医学   2篇
肿瘤学   31篇
  2023年   6篇
  2022年   7篇
  2021年   9篇
  2020年   10篇
  2019年   18篇
  2018年   21篇
  2017年   10篇
  2016年   13篇
  2015年   20篇
  2014年   20篇
  2013年   31篇
  2012年   34篇
  2011年   32篇
  2010年   29篇
  2009年   24篇
  2008年   34篇
  2007年   30篇
  2006年   34篇
  2005年   37篇
  2004年   33篇
  2003年   27篇
  2002年   25篇
  2001年   29篇
  2000年   26篇
  1999年   35篇
  1998年   18篇
  1997年   20篇
  1996年   21篇
  1995年   11篇
  1994年   8篇
  1993年   5篇
  1992年   13篇
  1991年   13篇
  1990年   28篇
  1989年   10篇
  1988年   15篇
  1987年   17篇
  1986年   23篇
  1985年   12篇
  1984年   20篇
  1983年   20篇
  1982年   15篇
  1981年   10篇
  1980年   6篇
  1979年   7篇
  1977年   7篇
  1975年   6篇
  1973年   6篇
  1972年   6篇
  1912年   3篇
排序方式: 共有955条查询结果,搜索用时 15 毫秒
51.
Ligase IV syndrome is a rare differential diagnosis for Nijmegen breakage syndrome owing to a shared predisposition to lympho‐reticular malignancies, significant microcephaly, and radiation hypersensitivity. Only 16 cases with mutations in LIG4 have been described to date with phenotypes varying from malignancy in developmentally normal individuals, to severe combined immunodeficiency and early mortality. Here, we report the identification of biallelic truncating LIG4 mutations in 11 patients with microcephalic primordial dwarfism presenting with restricted prenatal growth and extreme postnatal global growth failure (average OFC ?10.1 s.d., height ?5.1 s.d.). Subsequently, most patients developed thrombocytopenia and leucopenia later in childhood and many were found to have previously unrecognized immunodeficiency following molecular diagnosis. None have yet developed malignancy, though all patients tested had cellular radiosensitivity. A genotype–phenotype correlation was also noted with position of truncating mutations corresponding to disease severity. This work extends the phenotypic spectrum associated with LIG4 mutations, establishing that extreme growth retardation with microcephaly is a common presentation of bilallelic truncating mutations. Such growth failure is therefore sufficient to consider a diagnosis of LIG4 deficiency and early recognition of such cases is important as bone marrow failure, immunodeficiency, and sometimes malignancy are long term sequelae of this disorder.  相似文献   
52.
53.
Blood donors reactive by enzyme-linked immunosorbent assay for antibody to the human immunodeficiency virus (HIV) who showed atypical patterns of viral core protein reactivity on Western blot were monitored for several months. Characterization of their antibodies was performed by 1) use of recombinant HIV proteins; 2) determination of cross-reactivity to HTLV-I, HTLV-II, and HTLV-IV: 3) assessment of immune status; and 4) identification of potentially interfering autoantibodies. Nineteen of 20 donors maintained the same HIV antibody reactivity throughout the follow-up period; the other donor became fully antibody-positive. Eighteen of 20 donors' sera showed clear reactivity with HIV recombinant core proteins. Ten of 19 donor samples demonstrated cross-reactivity to HTLV-IV; 3 of these 10 also cross-reacted with HTLV-I. The immune status of all donors was normal, although the medical histories and HLA antibody screens suggested possible autoimmune reactivity in 9 of 18 donors. During follow-up interviews, three donors reported possible risk factors for HIV infection that had not been acknowledged at the time of blood donation. We conclude that exclusion of donors with these atypical serologic test results is warranted while further studies to determine significance are being conducted.  相似文献   
54.
55.
Long chain polyunsaturated fatty acids (LCPUFAs) are involved in the regulation of bone metabolism. Increased dietary consumption of n-3, and possibly some n-6, LCPUFAs may limit postmenopausal bone loss. The aim of this study was to determine the effects on bone of specific fatty acids within the n-3 and n-6 LCPUFA families in ovariectomized (OVX) rats. Rats were OVX or sham-operated and fed either a control diet (OVX and sham) or a diet supplemented with 0.5 g/kg body weight/day of γ-linolenic (GLA), eicosapentaenoic (EPA), docosahexaenoic (DHA) ethyl esters or a mixture of all three (MIX) for 16 weeks. Bone mineral content (BMC), area, and density and plasma concentrations of insulin-like growth factor-I, vitamin D, selected biochemical markers of bone metabolism, and parathyroid hormone (PTH) were determined. The OVX-induced decrease in lumbar spine BMC was significantly attenuated by DHA but not by EPA or GLA supplementation or supplementation with a mixture of all three LCPUFAs. Endosteal circumferences of tibiae were significantly greater in DHA and EPA compared to OVX. Plasma C-terminal telopeptide of type I collagen and osteocalcin concentrations were not significantly different in the DHA group compared to OVX. Femur BMC decreased by a significantly greater amount in GLA than OVX, and final plasma PTH concentrations were significantly higher in GLA compared to all other groups. In conclusion, DHA ameliorated OVX-induced bone mineral loss. GLA exacerbated post-OVX bone mineral loss, possibly as a result of PTH-induced bone catabolism.  相似文献   
56.
A home visiting service for parents whose mentally handicapped children were exhibiting difficult behaviour at home is described, with details of providing the service to 33 families with children aged from 3 to 15 years. The most frequent problems were socially unacceptable behaviour and incontinence, but self-help, communication, and play skills were also tackled. Visits were usually made every 3 to 4 weeks for periods from 3 to 27 months. Targets were achieved or some progress was gained in over two-thirds of the problems tackled. An average of eight hours was spent with each family. Home visiting proved as efficient as parent groups when measured by targets achieved as a function of parent and therapist time.  相似文献   
57.
58.
59.
60.
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