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   2015篇
  免费   111篇
  国内免费   10篇
医药卫生   2136篇
  2023年   15篇
  2022年   16篇
  2021年   108篇
  2020年   52篇
  2019年   60篇
  2018年   97篇
  2017年   36篇
  2016年   72篇
  2015年   78篇
  2014年   99篇
  2013年   120篇
  2012年   231篇
  2011年   213篇
  2010年   118篇
  2009年   90篇
  2008年   131篇
  2007年   111篇
  2006年   113篇
  2005年   81篇
  2004年   86篇
  2003年   51篇
  2002年   39篇
  2001年   16篇
  2000年   17篇
  1999年   6篇
  1998年   11篇
  1997年   5篇
  1996年   7篇
  1995年   10篇
  1994年   8篇
  1993年   4篇
  1992年   1篇
  1991年   3篇
  1990年   2篇
  1989年   4篇
  1988年   1篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1980年   4篇
  1978年   3篇
  1977年   2篇
  1974年   1篇
  1973年   1篇
  1970年   1篇
  1968年   1篇
  1964年   1篇
  1956年   1篇
排序方式: 共有2136条查询结果,搜索用时 15 毫秒
81.
Surgery alters the body’s homeostatic balance and defense mechanisms. In adults transient postoperative cellular and humoral immunosuppression after different degrees of operative stress has been reported. In children the immunologic consequences of operations are not elaborated. This study investigates the effect of minor and major surgery on early nonspecific immune response in terms of neutrophil counts and function. Forty-three children undergoing minor and major elective procedures were studied. Blood samples were collected before, immediately after, and 72 h after surgery. Total white cell count, differential neutrophil count, and neutrophil phagocytic function were studied using nitroblue tetrazolium test. Children were divided into two groups—group 1 underwent minor surgery and group 2 major surgery. In group 1 there was a significant drop in total counts after surgery, but in group 2 total counts were not affected. In both groups, the percentage of neutrophils increased immediately after surgery but fell to near or less than preoperative levels 72 h after surgery. However, the assessment of neutrophil functions by nitroblue tetrazolium test in both unstimulated and stimulated forms revealed it to be unchanged in group 1. In group 2 the unstimulated neutrophil function was elevated 72 h after surgery, whereas stimulated function was elevated immediately after surgery. Minor surgery does not alter the early nonspecific immune response. However, major surgery seems to induce a transient increase in neutrophil phagocytic activity.  相似文献   
82.
The purpose of present investigation was to understand the drug resistance reversal mechanism of 4‐hydroxy‐α‐tetralone ( 1 ) isolated from Ammannia spp. along with its semi‐synthetic derivatives ( 1a – 1e ) using multidrug resistant Escherichia coli (MDREC). The test compounds did not show significant antibacterial activity of their own, but in combination, they reduced the minimum inhibitory concentration (MIC) of tetracycline (TET). In time kill assay, compound 1 and its derivative 1e in combination with TET reduced the cell viability in concentration dependent manner. Compounds 1 and 1e were also able to reduce the mutation prevention concentration of TET. Both compounds showed inhibition of ATP dependent efflux pumps. In real time polymerase chain reaction (RT‐PCR) study, compounds 1 and 1e alone and in combination with TET showed significant down expression of efflux pump gene (yojI) encoding multidrug ATP binding cassettes (ABC) transporter protein. Molecular mechanism was also supported by the in silico docking studies, which revealed significant binding affinity of compounds 1 and 1e with YojI. This study confirms that compound 1 and its derivative 1e are ABC efflux pump inhibitors which may be the basis for development of antibacterial combinations for the management of MDR infections from inexpensive natural product.  相似文献   
83.
Circulating tumor cell (CTC) and cell‐free (cf) DNA‐based genomic alterations are increasingly being used for clinical decision‐making in oncology. However, the concordance and discordance between paired CTC and cfDNA genomic profiles remain largely unknown. We performed comparative genomic hybridization (CGH) on CTCs and cfDNA, and low‐pass whole genome sequencing (lpWGS) on cfDNA to characterize genomic alterations (CNA) and tumor content in two independent prospective studies of 93 men with mCRPC treated with enzalutamide/abiraterone, or radium‐223. Comprehensive analysis of 69 patient CTCs and 72 cfDNA samples from 93 men with mCRPC, including 64 paired samples, identified common concordant gains in FOXA1, AR, and MYC, and losses in BRCA1, PTEN, and RB1 between CTCs and cfDNA. Concordant PTEN loss and discordant BRCA2 gain were associated with significantly worse outcomes in Epic AR‐V7 negative men with mCRPC treated with abiraterone/enzalutamide. We identified and externally validated CTC‐specific genomic alternations that were discordant in paired cfDNA, even in samples with high tumor content. These CTC/cfDNA‐discordant regions included key genomic regulators of lineage plasticity, osteomimicry, and cellular differentiation, including MYCN gain in CTCs (31%) that was rarely detected in cfDNA. CTC MYCN gain was associated with poor clinical outcomes in AR‐V7 negative men and small cell transformation. In conclusion, we demonstrated concordance of multiple genomic alterations across CTC and cfDNA platforms; however, some genomic alterations displayed substantial discordance between CTC DNA and cfDNA despite the use of identical copy number analysis methods, suggesting tumor heterogeneity and divergent evolution associated with poor clinical outcomes.  相似文献   
84.
BK polyoma virus (PV) is one of the commonest post‐transplant viral infections, affecting approximately 15% of renal transplantation recipients, leading to graft failure in more than half of cases. The epithelial cells with polyoma viral inclusions in urine cytology specimens are termed “decoy cells” to caution pathologists not to misdiagnose these cells as cancer cells. The infected cells in urinary sediments are characterized by enlarged nucleus, basophilic intranuclear homogenous inclusions, and ground glass chromatin, which may cause diagnostic error in urine cytology. We report five cases of renal transplant patients, in which urine sample was positive for decoy cells. Routine urine cytology of post renal transplant patients with worsening renal function is a useful screening procedure to rule out PV reactivation, before ascertaining transplant rejection. Its cost‐effectiveness in addition to the short processing time makes it an invaluable tool in the evaluation of transplant recipients with symptoms suggestive of graft rejection.  相似文献   
85.
86.

Objectives

The aim of this study was to evaluate Streptococcus mutans adhesion to fluoride varnishes and subsequent change in biofilm accumulation and acidogenicity.

Methods

After producing fluoride varnish-coated hydroxyapatite discs using Fluor Protector (FP), Bifluorid 12 (BIF), Cavity Shield (CASH), or Flor-Opal Varnish White (FO), S. mutans biofilms were formed on the discs. To assess S. mutans adhesion to the discs, 4-h-old biofilms were analysed. To investigate the change in biofilm accumulation during subsequent biofilm formation, the biomass, colony forming units (CFU), and water-insoluble extracellular polysaccharides (EP) of 46-, 70-, and 94-h-old biofilms were analysed. To investigate the change in acidogenicity, pH values of the culture medium were determined during the experimental period. The amount of fluoride in the culture medium was also determined during the experimental period.

Results

BIF, CASH, and FO affected S. mutans adhesion (67–98% reduction) and subsequent biofilm accumulation in 46-, 70-, and 94-h-old biofilms. However, the reducing effect of the fluoride varnishes on the biomass, CFU count, water-insoluble EP amount, and acid production rate of the biofilms decreased as the biofilm age increased. These results may be related to the fluoride-release pattern of the fluoride varnishes. Of the fluoride varnishes tested, FO showed the highest reducing effect against the bacterial adhesion and subsequent biofilm accumulation.

Conclusions

Our findings suggest that if the results of these experiments are extrapolable to the in vivo situation, then reduced clinical benefit of using fluoride varnishes may occur with time.

Clinical significance

Fluoride varnish application can affect cariogenic biofilm formation but the anti-biofilm activity may be reduced with time.  相似文献   
87.
Oral verrucous hyperplasia is a whitish or pinkinsh elevated pre malignant lesion which occurs rarely. Its is also considered to be an early form of verrucous carcinoma. We have reported a case of verrucous hyperplasia which was diagnosed and treated with buccal fat pad as graft.  相似文献   
88.
Lipomas are among the most common benign tumors affecting the human body. However, they are relatively uncommon in the oral cavity. Oral lipomas are likely to affect cheek, tongue, lips, gingiva and rarely the floor of the mouth. We report a case of huge lipoma of the floor of the mouth, associated with difficulty in speech and mastication in a 72-year-old male. The tumor was completely excised and sent for histopathological examination, which confirmed the tumor to be a simple classical lipoma.  相似文献   
89.
Nateglinide has been widely used in the treatment of type-2 diabetics as an insulin secretogoga. A reliable, rapid, simple and sensitive reversed-phase high performance liquid chromatography (RP-HPLC) method was developed and validated for determination of nateglinide in rabbit plasma. The method was developed on Hypersil BDSC-18 column (250 mm×4.6 mm, 5 mm) using a mobile phase of 10 mM phosphate buffer (pH 2.5) and acetonitrile (35:65, v/v). The elute was monitored with the UV–vis detector at 210 nm with a flow rate of 1 mL/min. Calibration curve was linear over the concentration range of 25–2000 ng/mL. The retention times of nateglinide and internal standard (gliclazide) were 9.608 min and 11.821 min respectively. The developed RP-HPLC method can be successfully applied to the quantitative pharmacokinetic parameters determination of nateglinide in rabbit model.  相似文献   
90.
Objective  To study the value of coronal incisions for treating zygomatic complex fractures and evaluate the advantages, indications and complications associated with it. Method  In this prospective study, 12 patients were randomly selected regardless of age, sex requiring open reduction and internal fixation of communited zygomatic complex fractures with or without other associated fractures of the midface. Patients were all treated by coronal approach for open reduction and internal fixation of fracture of the zygomatic complex. Other local incisions were used if required. Results  In all cases postoperative complications were relatively minor except in one case were the temporal branch of facial nerve weakness persisted at 3 months. Whereas 5 cases reported with slight weakness of the temporal branch of the facial nerve which resolved at the end of 3 months. The time taken for exposure of the fracture site via the coronal incision had a mean of 28.7 minutes. There were no cases of flap infection and just 1 case of stitch abscess reported. The same case later reported with a hypertrophic scar formation of greater than 0.5cm at 3months. In all other cases scar formation was negligible and well hidden within the hairline. There were no reported cases of paraesthesia at the operated site or hollowing of the temporal fossa. Conclusion  The coronal incision provides excellent access to the zygomatic arch and zygomatic complex, aiding in good anatomical reduction and also has the added advantage of the scar hidden in the hairline. It also has disadvantages like long operating time, risk of facial nerve injury, scarring in patients with male pattern baldness, paraesthesia of operated site etc. Therefore the incision should be judiciously used and not overused and indications strictly applied.  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