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   435篇
  免费   31篇
  国内免费   2篇
耳鼻咽喉   8篇
儿科学   21篇
妇产科学   22篇
基础医学   36篇
口腔科学   32篇
临床医学   14篇
内科学   65篇
皮肤病学   18篇
神经病学   22篇
特种医学   6篇
外科学   87篇
综合类   17篇
预防医学   18篇
眼科学   35篇
药学   35篇
中国医学   4篇
肿瘤学   28篇
  2023年   7篇
  2022年   9篇
  2021年   22篇
  2020年   19篇
  2019年   20篇
  2018年   19篇
  2017年   13篇
  2016年   14篇
  2015年   13篇
  2014年   16篇
  2013年   24篇
  2012年   34篇
  2011年   46篇
  2010年   26篇
  2009年   23篇
  2008年   27篇
  2007年   16篇
  2006年   22篇
  2005年   24篇
  2004年   16篇
  2003年   10篇
  2002年   13篇
  2001年   4篇
  2000年   3篇
  1999年   2篇
  1998年   7篇
  1996年   5篇
  1995年   3篇
  1994年   4篇
  1989年   1篇
  1985年   1篇
  1983年   1篇
  1981年   1篇
  1980年   1篇
  1966年   1篇
  1964年   1篇
排序方式: 共有468条查询结果,搜索用时 15 毫秒
41.
Hereditary juvenile megaloblastic anemia due to vitamin B12 (cobalamin) deficiency is caused by intestinal malabsorption of cobalamin. In Imerslund-Grasbeck syndrome (IGS), cobalamin absorption is completely abolished and not corrected by the administration of intrinsic factor (IF); if untreated, the disease is fatal. Biallelic mutations either in the cubilin (CUBN) or amnionless (AMN) gene cause IGS. In a series of families clinically diagnosed with likely IGS, at least six displayed no evidence of mutations in CUBN or AMN. A genome-wide search for linkage followed by mutational analysis of candidate genes was performed in five of these families. A region in chromosome 11 showed evidence of linkage in four families. The gastric IF (GIF) gene located in this region harbored homozygous nonsense and missense mutations in these four families and in three additional families. The disease in these cases therefore should be classified as hereditary IF deficiency. Clinically, these patients resembled those with typical IGS; radiocobalamin absorption tests had been inconclusive regarding the nature of the defect. In the diagnosis of juvenile cobalamin deficiency, mutational analysis of the CUBN, AMN, and GIF genes provides a molecular characterization of the underlying defect and may be the diagnostic method of choice.  相似文献   
42.

Purpose

Evidence on the best surgical approach with the lowest lower lid complications (LLCs) in the treatment of orbital floor (OF) and periorbital fractures (POFs) is limited because of the absence of head-to-head studies. We performed this network meta-analysis (NMA) to compare various surgical approaches in treatment of OFs and POFs, with respect to LLCs.

Materials and methods

This NMA based on PRIMSA guidelines studied the incidence of the LLCs among various surgical approaches in the treatment of the OFs and POFs. We searched several databases from 1970 to March 2018. All clinical studies comparing different surgical approaches in treatment of OFs and POFs were included. Outcome variables were ectropion, entropion, scleral show and other complications. Predictor variables were transconjunctival approach (TCA), subciliary approach (SCA), subtarsal approach (STA) and infraorbital approach (IOA). Frequentist NMA was performed using STATA software.

Results

A total of 47 studies with 5267 cases of the OFs and POFs received ORIF using 4 surgical approaches with 6 comparisons were included. TCA significantly reduces the prevalence of ectropion than SCA (OR = 3.54, CI1.28–9.84), but no significant difference was found between TCA and, STA or TCA and IOA. SCA and STA significantly reduce the prevalence of entropion than TCA (OR = 5.02, CI, 1.79?14.06, OR = 0.11, CI, 0.02?0.57) respectively. We found no significant difference between the 6 comparisons with respect to other complications.

Conclusion

This NMA shows that the application of various surgical approaches leads to different incidences of LLCs. While TCA appears to have the lowest overall LLCs rate, STA has lowest rate among the transcutaneous approaches. The choice of an appropriate surgical approach for a given fracture should take these among other factors into consideration. Owing to the limitations of this study, we suggest that the results be interpreted with caution.  相似文献   
43.
PURPOSE: To determine risk factors for early failure of the bilamellar tarsal rotation procedure in trachomatous trichiasis. METHODS: This was a prospective study in which the bilamellar tarsal rotation procedure was performed on 638 eyelids in Menofiya governorate in Egypt over a 4-year period. An analysis was performed to determine the incidence of early surgical failure (defined as one or more lashes touching the eyeball) after 8 weeks and to determine the risk factors for these failures. RESULTS: Follow-up data were available on 599 eyes at 8 to 10 weeks after surgery. Considering all eyes, failure (one or more lashes touching the eyeball) was noted in 98 eyes (16.4%). Failure was associated with preoperative corneal staining (RR, 3.27; 95% CI, 2.34 to 4.57), preoperative corneal opacity (RR, 1.64; 95% CI, 1.15 to 2.34), the use of silk sutures (RR, 54.82; 95% CI, 7.72 to 389.4), and the use of 4 or more sutures (RR, 1.24; 95% CI, 1.04 to 1.48). CONCLUSIONS: The finding that specific sutures or needles was associated with early failure of the bilamellar tarsal plate rotation procedure for trachomatous trichiasis was unexpected and deserves further study.  相似文献   
44.
The failure to discover a significant new class of insecticides has led many researchers back to biodiscovery studies in the search for new and economically viable alternatives. After a preliminary screening of botanical extracts using descending series of concentrations (1,000, 500, 100, 50, and 5 mg/liter), 8 extracts from 2 potential botanical agents, Khaya senegalensis (Desrousseaux) and Daucus carota L., were tested against 4th instars of Culex annulirostris (Skuse) following the standard World Health Organization insecticide susceptibility methodology. The median lethal concentration (LC50) values for K. senegalensis against Cx. annulirostris using acetone, ethanol, hexane, and methanol extracts were 20.12, 5.1, 5.08, and 7.62 mg/liter, respectively. The LC50 values for D. carota against Cx. annulirostris using acetone, ethanol, hexane, and methanol extracts were 236.00, 36.59, 77.19, and 241.8 mg/liter, respectively. Extracts from K. senegalensis were more potent than those from D. carota against Cx. annulirostris and hexane and ethanol were the best solvents to extract essential oils from both plant species, respectively. In potency, K. senegalensis was similar to azadirachtin, but fractionation and compound isolation of the hexane extract in particular may reveal a potent phytochemical that could be compared to synthetic mosquitocides.  相似文献   
45.
46.
47.
48.
The management of neonatal surgical problems continues to pose considerable challenges, particularly in low-resource settings. The burden of neonatal surgical diseases in Africa is not well documented. The characteristics of some neonatal surgical problems are highlighted. Late presentation coupled with poor understanding of the milieu interior of the neonates by incompetent health care providers and poorly equipped hospitals combine to give rise to the unacceptable high morbidity and mortality in most parts of Africa. Proper training of all staff involved in neonatal health care coupled with community awareness must be vigorously pursued by all stakeholders. Various governments throughout the continent of Africa, in conjunction with international donor agencies, must not only provide an adequate budget for health care services and improve infrastructures, but must also deliberately encourage and provide funding for neonatal surgical care and research across the continent. The well-established pediatric surgical training programs, particularly in North and South Africa, should hold the moral responsibility of training all possible numbers of young surgeons from other African countries that do not have any existing pediatric surgical training programs or those countries suffering from remarkable shortage of trained pediatric surgeons.  相似文献   
49.
50.
A survey of 179 animals (black rats, dogs, sheep, buffaloes, cattle, donkeys, weasels, and cats) for Leptospira infection was conducted in Mahalla City (Lower Egypt). Blood, urine, and kidney were collected and tested by culture, microscopic agglutination test (MAT), and/or polymerase chain reaction (PCR). Among rats, 26% were positive by PCR, including 7% that were also positive by culture for L. interrogans serovars Grippotyphosa, Pyrogenes, and Icterohaemorrhagiae. L. borpetersenii serovar Polonica was isolated for the first time in Egypt in three rats. MAT titers ≥ 1:800 were observed in 11% of rats and 12% of dogs. L. interrogans serovar Grippotyphosa was detected in one cat. Sheep and donkeys were negative for leptospirosis by all methods. Buffaloes and cattle were seropositive in 20% and 44% of animals, respectively. Data indicate that several pathogenic serovars are circulating in the animals, which may pose exposure risks and account for high rates of acute febrile illness.  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