首页 | 官方网站   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   680篇
  免费   23篇
  国内免费   2篇
医药卫生   705篇
  2022年   3篇
  2021年   26篇
  2019年   5篇
  2018年   6篇
  2017年   4篇
  2016年   5篇
  2015年   10篇
  2014年   12篇
  2013年   8篇
  2012年   10篇
  2011年   9篇
  2010年   25篇
  2009年   21篇
  2008年   20篇
  2007年   15篇
  2006年   26篇
  2005年   14篇
  2004年   21篇
  2003年   13篇
  2002年   13篇
  2001年   17篇
  2000年   10篇
  1999年   17篇
  1998年   33篇
  1997年   24篇
  1996年   29篇
  1995年   18篇
  1994年   33篇
  1993年   14篇
  1992年   12篇
  1991年   21篇
  1990年   22篇
  1989年   23篇
  1988年   22篇
  1987年   23篇
  1986年   19篇
  1985年   20篇
  1984年   17篇
  1983年   12篇
  1982年   11篇
  1981年   9篇
  1980年   9篇
  1979年   3篇
  1978年   3篇
  1977年   4篇
  1976年   4篇
  1975年   4篇
  1968年   1篇
  1967年   1篇
  1961年   1篇
排序方式: 共有705条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
In order to evaluate the effects of pentoxifylline on sperm motility and longevity, a controlled in-vitro study was conducted on normozoospermic donor semen samples using the Cellsoft automated system for sperm motility analysis. After incubation and selection, pentoxifylline was found to improve the recovery of spermatozoa and to increase their velocity. In the subgroup of progressively motile spermatozoa, curvilinear velocity was also enhanced. It is concluded that pentoxifylline has an effect on the vigour, but not on the pattern, of sperm motion. Pentoxifylline did not improve the motility characteristics of senescent spermatozoa in normozoospermic sperm samples. Sperm survival, as shown by supra-vital staining, and motility longevity both decreased with time after pentoxifylline treatment.  相似文献   
5.
A study of 17 patients with autoimmune axonal or demyelinating peripheral neuropathy in combination with M-component is described. The M-component was associated with MGUS (monoclonal gammopathy of undetermined significance) in 12 patients, CLL in one patient, WaldenstrÖm's disease in one patient, and myeloma in three patients. Immunohistological examination with direct and indirect fluorescence showed binding of antibodies to nerve structures of the same class and light chain as seen in the M-component. In five cases of IgM M-component, the demyelinating neuropathy was caused by binding of the IgM M-protein and complement C3b to myelin-associated glycoproteins (MAG). In 12 cases with axonal neuropathy, binding of IgG to the connective tissue of the peri- and endoneurium was found in 50% of cases, IgM in five cases, and IgD in one case. None of the patients had central nervous system (CNS) symptoms. The clinical and therapeutic difficulties are discussed; only two patients with an acute course responded to immunosuppression. A marked co-expression of other autoimmune phenomena is interpreted in the light of cross-reactions between the autoantibody and similar tissue autoantigens.  相似文献   
6.
7.
8.
Rotational ablation of balloon angioplasty failures   总被引:1,自引:0,他引:1  
In this series, we evaluated the use of rotational ablation in stenoses that were previously refractory to balloon angioplasty. Forty-one stenoses were treated; in 26, the balloon did not adequately expand within the lesion and in 15 the balloon could not be delivered to the stenosis. Rotational ablation was technically successful in 40 of 41 (97.6%) of the lesions attempted. Twenty-four patients have been followed (mean time = 9 +/- 5 months) and the restenosis rate was similar to that of balloon angioplasty. Rotational ablation appears well suited and may be the treatment of choice for heavily calcified, severely angulated, and diffusely diseased vessels.  相似文献   
9.
Immunization with an Anaplasma marginale surface protein complex containing two polypeptides (Am105U and Am105L), each having a molecular weight of 105,000, protected cattle against challenge with virulent organisms. These polypeptides were immunoprecipitated together from detergent extracts of A. marginale by a neutralizing monoclonal antibody. After surface radioiodination of intact parasites, both Am105U and Am105L contained the radiolabel. To define the structural and antigenic relationships between Am105U and Am105L and to determine individual efficacies as protective immunogens, we cloned and expressed A. marginale DNA in Escherichia coli. We identified recombinant bacteria which expressed a novel protein of 105,000 molecular weight as a major cellular component. The recombinant protein was structurally and antigenically homologous to Am105L. There were multiple, partially homologous copies of the cloned DNA sequence in the rickettsial genome.  相似文献   
10.
Recently, in-vitro maturation (IVM) of immature human oocytes recovered from non-stimulated follicles has been applied in the treatment of infertility. However, in previous reports, very few embryos cultured in conventional medium have reached the expanded blastocyst stage following in-vitro maturation and fertilization (IVM/IVF). The objective of this study was to investigate whether the developmental competence of human embryos following IVM/IVF could be enhanced by the use of a human ampullary cell co-culture system. Immature human oocytes were aspirated from small follicles at Caesarean section and then cultured in medium containing human menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes were randomly cultured either in conventional culture medium alone or in the co-culture system. Of 48 embryos cultured in conventional medium alone, all arrested at the 2-16- cell stage on day 3 after insemination. Of 46 embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at the 2-16-cell stage. Six embryos (13%) developed to the morula stage. Fourteen embryos (30.4%) developed to expanded blastocysts and two blastocysts were hatching on day 7 after insemination. We conclude that co-culture significantly enhances the development of blastocysts in embryos resulting from IVM/IVF.   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-23

京公网安备 11010802026262号