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   285篇
  免费   14篇
耳鼻咽喉   1篇
儿科学   19篇
妇产科学   13篇
基础医学   24篇
口腔科学   10篇
临床医学   36篇
内科学   58篇
皮肤病学   4篇
神经病学   13篇
特种医学   60篇
外科学   16篇
综合类   4篇
预防医学   20篇
眼科学   1篇
药学   11篇
中国医学   1篇
肿瘤学   8篇
  2021年   1篇
  2018年   1篇
  2017年   4篇
  2016年   3篇
  2015年   16篇
  2014年   20篇
  2013年   13篇
  2012年   10篇
  2011年   6篇
  2010年   14篇
  2009年   4篇
  2008年   3篇
  2007年   2篇
  2006年   8篇
  2005年   8篇
  2003年   1篇
  2001年   1篇
  2000年   3篇
  1999年   1篇
  1998年   6篇
  1997年   14篇
  1996年   11篇
  1995年   11篇
  1994年   15篇
  1993年   8篇
  1992年   3篇
  1991年   6篇
  1990年   4篇
  1989年   15篇
  1988年   13篇
  1987年   8篇
  1986年   8篇
  1985年   7篇
  1984年   8篇
  1983年   5篇
  1982年   3篇
  1981年   5篇
  1980年   7篇
  1978年   3篇
  1977年   6篇
  1976年   5篇
  1975年   2篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1968年   1篇
  1965年   1篇
  1958年   1篇
  1956年   1篇
排序方式: 共有299条查询结果,搜索用时 15 毫秒
51.

BACKGROUND AND PURPOSE

The serine and cysteine peptidase inhibitor, BbCI, isolated from Bauhinia bauhinioides seeds, is similar to the classical plant Kunitz inhibitor, STI, but lacks disulphide bridges and methionine residues. BbCI blocks activity of the serine peptidases, elastase (Kiapp 5.3 nM) and cathepsin G (Kiapp 160.0 nM), and the cysteine peptidase cathepsin L (Kiapp 0.2 nM). These three peptidases play important roles in the inflammatory process.

EXPERIMENTAL APPROACH

We measured the effects of BbCI on paw oedema and on leucocyte accumulation in pleurisy, both induced by carrageenan. Leucocyte–endothelial cell interactions in scrotal microvasculature in Wistar rats were investigated using intravital microscopy. Cytokine levels in pleural exudate and serum were measured by elisa.

KEY RESULTS

Pretreatment of the animals with BbCI (2.5 mg·kg−1), 30 min before carrageenan-induced inflammation, effectively reduced paw oedema and bradykinin release, neutrophil migration into the pleural cavity. The number of rolling, adhered and migrated leucocytes at the spermatic fascia microcirculation following carrageenan injection into the scrotum were reduced by BbCI pretreatment. Furthermore, levels of the rat chemokine cytokine-induced neutrophil chemo-attractant-1 were significantly reduced in both pleural exudates and serum from animals pretreated with BbCI. Levels of interleukin-1β or tumour necrosis factor-α, however, did not change.

CONCLUSIONS AND IMPLICATIONS

Taken together, our data suggest that the anti-inflammatory properties of BbCI may be useful in investigations of other pathological processes in which human neutrophil elastase, cathepsin G and cathepsin L play important roles.  相似文献   
52.
53.
ObjectiveTo explore the prevalence, pathogenicity, and antibiotic susceptibility patterns of urinary tract infections at the University of Port Harcourt Teaching Hospital.MethodsSamples from 400 patients with a presumptive diagnosis of urinary tract infection including 250 non pregnant females and 150 males were used for this study. They were distributed into two groups: children aged 2 to 17 (Group A) and adults aged 18 to 75 (Group B). The standard wire loop and agar diffusion technique were employed for culture and susceptibility testing, respectively. Data obtained were analysed using SPSS, version 14.Results30.0% of Group A and 41.0% of Group B had significant bacteriuria with 66.7% and 79.3% as females, respectively. The commonest isolates cultured were Escherichia coli (32.8%), Staphylococcus aureus (17.2%), and Klebsiella spp. (16.4%). About 76.6% of isolates were sensitive to the fluorinated quinolones, 31.2% to the aminoglycosides, and 22.7% to the urinary antiseptic, nitrofurantoin. The isolates were non-sensitive to tetracycline (93.8%), cotrimoxazole (92.2%), and nalidixic acid (86.7%). Most isolates showed non-uniform sensitivity patterns to the cephaloporins (cefuroxime and ceftazidime). Pseudomonas spp. isolates were generally resistant to the fluorinated quinolones.ConclusionThough the fluorinated quinolones are still largely effective for empirical therapy in urinary tract infections, the importance of prior sensitivity testing in checking the emergence of bacterial antibiotic resistance can not be overemphasized.  相似文献   
54.
The effects of local hyperthermia treatment on contact sensitivity (CS) and on the number of Langerhans cells (LCs) were studied in mice. CS was significantly suppressed when mice were sensitized in the hyperthermia treated skin I, 2 or 4 days after treatment (43 degrees C for 45 min). This suppressive effect was not observed 7 or 14 days after the treatment. CS was also suppressed when mice were sensitized in non-treated skin I day after the treatment. The density of LCs detected as ATPase-positive cells also decreased significantly 1, 2, 4 and 7 days after the treatment. There appeared to be a positive correlation between the number of LCs and the extent of CS when mice were sensitized at hyperthermia treated skin. It was observed that this suppressive effect on CS was dose- and temperature-dependent. It could be transferred by spleen cells from the hyperthermia treated and DNFB-sensitized donors, and was antigen specific when spleen cells were transferred before sensitization of the recipient mice. This indicated it was, in part, associated with the induction of suppressor cells. These findings suggest that local hyperthermia treatment reduces the number of LCs with subsequent suppression of the induction phase of delayed-type hypersensitivity by the generation of antigen-specific suppressor cells.  相似文献   
55.
The alcohol availability literature indicates that under some conditions, physical availability is positively associated with per capita alcohol consumption. Smart (1980) suggested that at the individual level, subjective and social aspects of availability may mediate and outweigh the influence of physical availability. The study described here examined the simultaneous effects of physical, subjective, and social availability on alcohol consumption. Standardized telephone interviews were conducted with 781 adult drinkers. As hypothesized, physical availability was not a significant multivariate predictor of alcohol consumption for residents of high, medium, and low alcohol outlet density counties in Michigan (USA). Subjective and social availability indicators were significant predictors of alcohol consumption. Similar patterns of results were found in multiple regression analyses for blacks and whites and women and men, although blacks and women consumed less alcohol than did whites and men. The theoretical and practical implications of these results are discussed.  相似文献   
56.
Between January 1980 and July 1983, percutaneous transluminal angioplasty was attempted on 137 stenotic renal arteries in 100 patients. At termination of follow-up studies (3-39 months, mean of 16 months), 70% of those treated for hypertension had benefited from the procedure. Stenosis secondary to fibromuscular dysplasia responded better than stenosis from arteriosclerosis (85% and 65% of the patients, respectively). Benefit was minimal for those with stenosis of the renal artery ostium or renal insufficiency. Determining levels of renal vein renin before angioplasty is helpful in selecting patients; following angioplasty, this has considerable significance in predicting the success of the procedure.  相似文献   
57.
58.
The Enhancing Effect of Spawning on Elimination of a PersistentPolychlorinated Biphenyl from Female Yellow Perch. VODICNIK,M. J., AND PETERSON, R. E. (1985). Fundam. Appl. Toxicol. 5,770–776. Distribution and elimination of 2,5,2',5'-tetrachloro[14C]biphenyl.(4-CB) were studied for 6 months after exposing sexually maturefemale yellow perch to the compound in water and transferringthem to flowing 4-CB-free water. Perch that were exposed inJanuary spawned in May, and the study was terminated in June.During the first 4 months after exposure, the t for whole-bodyelimination was 22 weeks, primarily by elimination of 4-CB fromthe viscera and carcass. During spawning, enhanced elimination(t < 0.7 weeks) was due to the voiding of eggs containing4-CB. After spawning, whole-body elimination returned to a slowerrate (t = 16.3 weeks). Prior to the enhancement in 4-CB eliminationrate during spawning, there was a redistribution of 4-CB residueswithin the body of the perch which was characterized by a transferof 4-CB residues from primarily the carcass and viscera to eggs.Two weeks after exposure, 30% of the initial 4-CB body burdenwas distributed to the eggs, whereas just prior to spawning,about 50% was present in this tissue. These findings demonstratethat egg maturation and spawning result in a significant reductionin the body burden of a persistent polychlorinated biphenylin a lean-fish species.  相似文献   
59.
60.

Background

There is increased reliance on traditional herbal medicines by several millions of people worldwide, especially in West Africa and Nigeria in particular. This is due to escalating cost of good quality drugs and consequent proliferation of faked cheaper drugs. However, non standardization of production and handling methods have resulted in herbal medicines with varying quality and safety indices, thus resulting in possible public health concerns. This work investigated the microbial load and aflatoxin levels in herbal medicines from selected states in Nigeria.

Materials and Methods

A total of 210 samples obtained from various renowned herbal medicine practitioners from some selected states in Nigeria, based on their medicinal uses, were analyzed to determine the microbial load by the plate count method and aflatoxin contamination levels using thin layer chromatography with aflatoxin standards.

Results

At least six bacterial genera (Bacillus, Pseudomonas, Salmonella, EPEC, EHEC, Streptococcus and other coliforms) and 6 fungal genera (Aspergillus, Penicillium, Rhizopus, Cladosporium, Geotricum and Candida) were isolated. Aflatoxin B1, B2 and G1 were detected in varying concentrations in the samples analyzed, with an average occurrence of 18.6%. Some of these herbal concoctions were found to contain unacceptably high bioload, according to WHO standards.

Conclusion

Microbial contamination and the presence of aflatoxins in herbal medicines appear to be an endemic problem in Nigeria, as observed in this work, probably due to poor observation of basic hygiene during preparations and poor storage conditions. The findings in this work may serve in developing and instituting public health standards for the production and safety of herbal remedies in Nigeria.  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