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   1836篇
  免费   69篇
  国内免费   9篇
耳鼻咽喉   12篇
儿科学   75篇
妇产科学   34篇
基础医学   191篇
口腔科学   57篇
临床医学   159篇
内科学   379篇
皮肤病学   44篇
神经病学   77篇
特种医学   158篇
外科学   159篇
综合类   82篇
预防医学   103篇
眼科学   83篇
药学   189篇
中国医学   8篇
肿瘤学   104篇
  2023年   12篇
  2022年   42篇
  2021年   58篇
  2020年   44篇
  2019年   47篇
  2018年   60篇
  2017年   28篇
  2016年   41篇
  2015年   48篇
  2014年   59篇
  2013年   73篇
  2012年   122篇
  2011年   124篇
  2010年   81篇
  2009年   70篇
  2008年   93篇
  2007年   87篇
  2006年   57篇
  2005年   56篇
  2004年   58篇
  2003年   50篇
  2002年   46篇
  2001年   59篇
  2000年   56篇
  1999年   50篇
  1998年   33篇
  1997年   15篇
  1996年   19篇
  1995年   15篇
  1994年   15篇
  1993年   9篇
  1992年   20篇
  1991年   27篇
  1990年   21篇
  1989年   18篇
  1988年   26篇
  1987年   20篇
  1986年   18篇
  1985年   18篇
  1984年   12篇
  1983年   11篇
  1982年   5篇
  1979年   15篇
  1977年   10篇
  1976年   9篇
  1975年   10篇
  1974年   7篇
  1972年   6篇
  1971年   5篇
  1968年   6篇
排序方式: 共有1914条查询结果,搜索用时 15 毫秒
101.
102.
Antioxidants may play an important role in immune evasion by schistosome parasites. Previous studies have focused on the roles of superoxide dismutase and glutathione S-transferase. In the present study, glutathione peroxidase (GPX) activity was measured in different fractions of worm extracts from several developmental stages of Schistosoma mansoni. The enzyme activity was shown to be developmentally regulated, with higher specific activities being found in the tegument-enriched Nonidet P-40 extract of adult worms (the stage least susceptible to immune killing) than in the larval stages (which are most susceptible to immune elimination). In all extracts tested, the activity against cumene hydroperoxide, even when glutathione S-transferase activity was removed, was higher than that for hydrogen peroxide. The expression of GPX cDNA in pGEX-2T by bacteria produced a 50-kDa fusion protein and a 32-kDa truncated protein. The latter was due to termination at the internal UGA codon that codes for selenocysteine. GPX activity was detected in the recombinantly produced GPX but not with Sj26-glutathione S-transferase from the vector. Mutating the TGA codon to TGT produced a full-length product, GPXm (19 kDa), that was used to produce 19 monoclonal antibodies. Anti-GPXm monoclonal antibodies recognized a 19-kDa molecule in adult-worm extract which, upon removal by immunoprecipitation, resulted in the loss of over 90% of the GPX activity, suggesting that a single form of GPX exists in the schistosome.  相似文献   
103.
Summary: On clinical examination of 1232 sheep belonging to the urban and rural areas of Punjab (India) lesions of ringworm could be detected in 22 animals giving an incidence of 1.78%. Animals below the age of 6 months were more frequently affected (7.4%), than those above 6 months (1.03%). Culturally, T. verrucosum, T. mentagrophytes and M. gypseum could be isolated from the skin scrapings of four, two and one sheep respectively.
Zusammenfassung: Bei der klinischen Untersuchung von 1.232 Schafen aus der städtischen und ländlichen Gegend von Punjab (Indien) wurden bei 22 Tieren Veränderungen gefunden, die auf eine Hautmykose verdächtig waren (1,78%). Tiere, die jünger als 6 Monate waren, schienen häufiger befallen zu sein (7,4%) als die älteren Tiere (1,03%). Kulturell konnten T. verrucosum, T. mentagrophytes und M. gypseum aus der Haut von 4, bzw. 2, bzw. 1 Tier isoliert werden.  相似文献   
104.
105.
Human polymorphonuclear leukocytes (PMNs) were labeled with indium-111 oxine in ethanol, and the effects of the labeling procedure, radioactivity, and concentrations of oxine and ethanol on PMN function and structure were studied in vitro. The standard labeling procedure did not alter the viability, random migration, chemotaxis, bactericidal capacity, or the ultrastructure of PMNs. Exposure to higher doses of radioactivity, or to higher concentrations of ethanol, had no appreciable effects on random migration and chemotaxis of PMNs. A dose-dependent reduction in their random migration and chemotaxis was observed when higher concentrations of oxine were used. These results indicate that In-111-labeled PMNs are structurally intact and have normal in vitro locomotion and bactericidal activity. Indium-111-labeled PMNs should be suitable for studying the kinetics and distribution of these cells in health and disease.  相似文献   
106.
Five cases of xeroderma pigmentosum have been presented, three of the patients belonging to one family. There was no history of consanguineous marriages in this series. All five patients had advanced ocular complications. Three presented with multiple basal cell carcinomata, which were treated by radiotherapy in two cases and surgery in one. One patient presented with a dermatofibroma, which does not seem to have been reported earlier in association with this disease. Reconstructive techniques such as the use of flaps and grafts arc safe, and the healing response is quite satisfactory.  相似文献   
107.
OBJECTIVE: To estimate the effectiveness of Bacillus Calmette Guerin (BCG) vaccination in the prevention of leprosy. Study design. Population-based case-control study. METHODS: The study was carried out in Yavatmal District, Maharashtra, India. It included 364 cases of leprosy (diagnosed by the World Health Organization's criteria), born since 1962, that were detected during a leprosy survey conducted by the Government of Maharashtra in 2,175,514 people. Each case was pair-matched with one neighbourhood control for age, sex and socio-economic status. Exclusion criteria for controls included past or current history of tuberculosis or leprosy. BCG vaccination status was assessed by examination for the presence of a BCG scar, immunization records if available and information from subjects/parents of children. Subjects who were uncertain about BCG vaccination were not included. RESULTS: A significant protective association between BCG and leprosy was observed [odds ratio=0.46, 95% confidence intervals (CI) 0.34-0.61]. Overall vaccine effectiveness (VE) was 54% (95% CI 39-66). BCG effectiveness against multibacillary, paucibacillary and single skin lesion leprosy was 68% (95% CI 26-86), 57% (95% CI 29-74) and 48% (95% CI 22-65), respectively. Analysis of linear trend revealed a significant linear association between the protective effect of BCG and the type of leprosy. The BCG vaccine was more effective in those aged < or =20 years compared with those aged >20 years (VE 61%, 95% CI), among females compared with males (VE 60%, 95% CI), in lower socio-economic strata compared with upper and middle strata (VE 57%, 95% CI), and in subjects who had a BCG scar size < or =5 mm compared with those with a BCG scar size >5 mm (VE 61%, 95% CI). However, these differences were not statistically significant, as reflected by the overlapping 95% CIs. The overall prevented fraction was 35% (95% CI 22-46). CONCLUSION: The current study identified a beneficial role of BCG vaccination in the prevention of leprosy in the study population.  相似文献   
108.
Ophthalmomyiasis     
Ophthalmomyiasis is a rare condition. Here two such patients, one of 70-year-old male farmer with history of neglected trauma presented with painful swelling with sinus of right orbit and the second one of 65-year-old female destitute who presented with fungating mass near the medial canthus of left eye with pain and bleeding are reported. All the maggots were removed after applying ether.  相似文献   
109.
110.
Serum Zn and Cu levels were measured by atomic absorption spectrophotometry in 117 children (aged 3 months to 5 years), divided into two groups; 80 children suffered from severe malnutrition and 37 children served as controls. Significantly lower levels of serum Zn and Cu were found in the malnutrition group. Zn levels of 2.59±0.15 µg/ml as compared to 3.92±0.35 µg/ml in the control group (P=0.0037) and Cu levels of 0.74±0.05 µg/ml in the malnutrition group as compared to 1.19±0.08 µg/ml in the control group were observed. Superoxide dismutase activity in children with severe malnutrition was 21.13±0.75 U/min per mg protein as compared to 26.02±0.66 U/min per mg protein in controls. Absence of breast-feeding, recurrent respiratory tract infection and diarrhoea correlated significantly with low serum Zn and Cu levels. Hypoproteinaemia and anaemia in malnourished children were also associated with a significant decline in both serum Zn and Cu levels. Conclusion:Serum trace element deficiency leading to depleted antioxidant protection may be a contributing factor to the pathophysiology of protein malnutrition and replacement of these elements in the management of this condition might be important.  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