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   246篇
  免费   10篇
儿科学   19篇
妇产科学   8篇
基础医学   29篇
口腔科学   6篇
临床医学   22篇
内科学   39篇
皮肤病学   6篇
神经病学   19篇
特种医学   5篇
外科学   74篇
综合类   4篇
预防医学   8篇
眼科学   3篇
药学   10篇
肿瘤学   4篇
  2022年   4篇
  2021年   4篇
  2020年   1篇
  2018年   3篇
  2017年   3篇
  2016年   4篇
  2015年   4篇
  2014年   5篇
  2013年   7篇
  2012年   10篇
  2011年   9篇
  2010年   6篇
  2009年   9篇
  2008年   4篇
  2007年   11篇
  2006年   7篇
  2005年   12篇
  2004年   16篇
  2003年   11篇
  2002年   11篇
  2001年   8篇
  2000年   9篇
  1999年   6篇
  1998年   3篇
  1997年   4篇
  1996年   2篇
  1995年   2篇
  1994年   6篇
  1993年   2篇
  1992年   6篇
  1991年   4篇
  1990年   6篇
  1989年   6篇
  1988年   10篇
  1987年   8篇
  1986年   6篇
  1985年   5篇
  1984年   4篇
  1983年   5篇
  1982年   3篇
  1978年   2篇
  1976年   3篇
  1975年   1篇
  1974年   1篇
  1973年   3篇
排序方式: 共有256条查询结果,搜索用时 187 毫秒
1.
Re-orchiopexy was performed in 33 boys (42 testes) in order to place an undescended testis in the scrotum after failure of the initial operation. Success was achieved in 80.9%. Seven of the 10 testes, reported to have short spermatic vessels at the first surgery, had no elongation of the vessels and only 1 of these resulted in a high scrotal location of the testis. It appears that most orchiopexy failures are the result of technical failures of the initial procedure. Standard orchiopexy with extensive mobilization of the spermatic vessels and testis can successfully correct most of the undescended testes. However, the preferred management for the intra-abdominal testis with short vessels may be transection of the spermatic vessels rather than a planned two-stage technique.  相似文献   
2.
The zone of progenitor cells of mandibular condyles of neonatal mice was kept in an organ culture system for up to 8 days. Qualitative and quantitative determinations indicated a pronounced proliferative activity during the initial phases of the culture followed by a differentiation phase and the acquisition of typical hyaline cartilage. The mature hypertrophic chondrocytes were found to be surrounded by cartilage-specific macromolecules such as type II collagen, cartilage proteoglycans, and cartilage anchorin. The extracellular mineralization proceeded along matrix vesicles as is usually noted in vivo. A unique finding in this study was the observation that explants comprising cartilage progenitor cells and their adjacent extracellular matrix succeeded in repairing the damaged condylar in vitro.  相似文献   
3.
Silane-coated silica particle solutions (ISolate(TM) and PureSperm)TM)) and iodixanol (OptiPrep(TM)) were compared to polyvinylpyrrolidone (PVP)-coated silica particles (Percoll(TM)) in their efficacy to recover spermatozoa by gradient centrifugation for use in assisted reproductive procedures. Efficacy was assessed in terms of percentages of sperm recovery, sperm vitality and motility, normal sperm morphology and normal sperm chromatin condensation. No significant difference was found in the recovery of spermatozoa for men with both normal sperm counts and oligozoospermia, between PVP-coated and silane-coated particle solutions. Iodixanol had significantly lower sperm recovery compared to the other products. Sperm vitality, progressive motility, normal morphology and normal chromatin condensation did not differ significantly between any of the sperm isolation products.   相似文献   
4.
Plasmid DNA vectors have been constructed with minigenes encoding a single cytotoxic T lymphocyte (CTL) epitope from either the M2 protein of respiratory syncytial virus (RSV) or from the nucleoprotein of measles virus (MV) with or without a signal sequence (also called secretory or leader sequence). Following intradermal immunization, plasmids in which the CTL epitopes were expressed in-frame with the signal sequence were more effective at inducing peptide- and virus- specific CTL responses than plasmids expressing CTL epitopes without the signal sequence. This immunization resulted in protection against MV-induced encephalitis and a significant reduction in viral load following RSV challenge. The reduction of viral load following RSV challenge was abrogated by prior injection with anti-IFN-gamma antibodies. These results highlight the ability of epitope-based DNA immunization to induce protective immune responses to well-defined epitopes and indicate the potential of this approach for the development of vaccines against infectious diseases.   相似文献   
5.
The sera of 49 healthy IgA-deficient (SIgAD) subjects were evaluated for the presence of autoantibodies directed against 10 different nuclear and cytoskeletal antigens, as well as for the presence of the common lupus anti-DNA idiotype (16/6 Id). Twenty-nine sera were from IgG subclass-deficient subjects (4 = IgG2, 25 = IgG3), and 25 from normal healthy subjects, used as controls. The incidence of antinuclear but not anti-cytoskeletal antibodies were found to be significantly greater in the SIgAD group, as compared to the IgG-deficient subjects and the normal controls. Overall, 39% of SIgAD sera demonstrated polyreactivity, namely reactivity against more than one nuclear antigen. The incidence of specific antibody detection ranged from 37% against cardiolipin to 12% against RNP in the IgA-deficient group, albeit not with statistical significance in all cases when compared to the control group. Isotype evaluation of the antinuclear and related antibodies in the SIgAD group showed a greater tendency towards IgG. This increased incidence of autoantibody production in SIgAD may preceed the development of an overt autoimmune disease in the future.  相似文献   
6.
Splenectomy has long been an establishmd surgical procedure in various conditions, including trauma. Because total splenectomy has often been correlated with sepsis, every surgeon tries to preserve as much of the injured spleen as possible. Contradictory reports have been published as to whether regeneration of the remaining splenic tissue is possible. In the present study, 28 Sprague-Dawley rats ( 100 g) were divided into four groups. They underwent two-thirds partial splenectomy; the remaining splenic tissue was examined after 1 day, 1 week, 1 month and 3 months postoperatively. The following parameters were determined: weight, length, and protein and deoxyribonucleic acid (DNA) content of the remaining spleen. The incorporation of 3H-thymidine into the remaining spleen tissue was also measured. Histology and radioautography were studied in parallel. Results were compared with control animals that were operated upon but with no partial splenectomy. One day, 1 week, and 1 month following partial splenectomy, a slight increase in weight, length, protein, and DNA content as well as incorporation of the radioisotope into cellular DNA was found. By 3 months after the operation, there was no difference in the above parameters between the experimental animals and controls.Radioautographs indicated that most of the cells containing the isotope were situated in the perinodular areas in the red pulp, accompanied by an increased number of inflammatory cells. We found this cell proliferation mainly along the cut surface of the spleen. The slight increase that was found in all the parameters examined up to 1 month after partial splenectomy is an inflammatory response and not regeneration of the spleen.  相似文献   
7.
8.
9.

Background

Literature abounds linking one’s job to certain unpalatable health outcomes. Since exposures to hazardous conditions in industrial environments often results in sundry health effects among workers, we embarked on this study to investigate the hepatic health effects of occupational activities in the petroleum refining and distribution industry.

Method

Biochemical markers of liver functions were assayed in plasma, using Reflotron dry chemistry spectrophotometric system. The study was conducted on randomly selected workers of Port Harcourt Refining Company (PHRC) and Pipelines and Petroleum Product Marketing Company (PPMC) both in Alesa-Eleme near Port Harcourt, Nigeria, as well as non-oil work civil servants serving as control subjects.

Result and conclusion

Results showed that, bilirubin ranged 0.3-1.6 mg/dl with a mean of 0.66±0.20mg/dl among the oil workers as against 0.5-1.00mg/dl with a mean of 0.58±0.13mg/dl in non-oil workers, Alkaline phosphatase ranged 50.00-296.00u/l (mean: 126.21±39.49u/l) in oil workers as against 40.20-111u/l (mean: 66.83±18.54u/l) for non-oil workers, Aspartic transaminases (AST) ranged 5.80-140.20u/l (mean: 21.81±11.49u/l) in oil workers against 18.00-44.00u/l (mean: 26.89±6.99u/l) for non-oil workers, while Alanine transaminases (ALT) ranged 4.90-86.00u/l (mean: 22.14±11.28u/l) in oil workers as against 10.00-86.60u/l (mean: 22.30±10.22u/l) for the non-oil workers. A close study of the results revealed that although the mean values for all the studied parameters were still within the parametric reference ranges, however, relative to the referents, there were significant increases (P<0.05) in plasma bilirubin (though anicteric) and alkaline phosphatase that was not matched with a corresponding increase in the plasma transaminases, suggesting a possibility that toxic anicteric hepatoxicity is part of the potential health effects of sundry exposures in the Nigeria petroleum oil refining and distribution industry. Gender differentiation data showed that though the mean values for the parameters were higher in males than females, the increases were not significant in most cases (P>0.05), whereas data for age and exposure period classifications revealed that irrespective of the age of the worker, the effects are likely to start after the first five years, manifesting fully after the first decade of occupational exposures. Thus, an update of industrial/occupational health measures is necessary for a safer and healthier work environment.  相似文献   
10.
Osteoarthritis is a degenerative joint disease characterized by destruction of the articular cartilage in aging and senescence. The aim of this study was to study the possible treatment of this disease by intraarticular injection of growth factors to osteoarthritic joints of aged animals. 20-month-old female ICR mice were injected with insulin-like growth factor (IGF-1), transforming growth factor-beta (TGF-beta) or TGF-beta+IGF-1 on days 1, 4, and 7. On day 9 the joints were dissected and cultured in the presence of 35S-sulfate and 3H-thymidine. Combined treatment of TGF-beta and IGF-1 resulted in elevated 3H-thymidine incorporation and DNA and protein contents, reduction of 35S-sulfate incorporation and alkaline phosphatase activity, with no significant change in the activity of acid phosphatase. Following injections of TGF-beta, contents of DNA and protein, and incorporations of 3H-thymidine were induced, and 35S-sulfate and alkaline phosphatase activity were reduced. Treatment with IGF-1 resulted in reduced incorporation of 3H-thymidine with no significant changes in the activity of acid phosphatase. Atypically hypertrophic chondrocytes were observed along the articular surface and the endogenous production of TGF-beta and of IGF-1, as revealed by immunohistochemistry, was reduced. It is concluded that although 3H-thymidine incorporation and alkaline phosphatase activity appeared to be induced by TGF-beta and IGF-1, the overall responsiveness of cartilage from aged mice to these growth factors appeared to be inhibitory. Moreover, their effects appeared to be limited to specific cell populations in the cartilage itself.  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