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   223篇
  免费   43篇
  国内免费   30篇
耳鼻咽喉   1篇
儿科学   13篇
基础医学   47篇
临床医学   28篇
内科学   69篇
神经病学   7篇
特种医学   59篇
外科学   27篇
综合类   14篇
预防医学   7篇
眼科学   1篇
药学   15篇
肿瘤学   8篇
  2023年   1篇
  2022年   2篇
  2021年   1篇
  2018年   8篇
  2017年   4篇
  2016年   7篇
  2015年   7篇
  2014年   2篇
  2013年   2篇
  2012年   3篇
  2011年   4篇
  2010年   7篇
  2009年   8篇
  2008年   6篇
  2007年   14篇
  2006年   7篇
  2005年   13篇
  2004年   8篇
  2003年   8篇
  2002年   8篇
  2001年   9篇
  2000年   17篇
  1999年   8篇
  1998年   14篇
  1997年   8篇
  1996年   7篇
  1995年   13篇
  1994年   14篇
  1993年   7篇
  1992年   2篇
  1991年   9篇
  1990年   4篇
  1989年   12篇
  1988年   7篇
  1987年   5篇
  1986年   4篇
  1985年   4篇
  1984年   6篇
  1983年   4篇
  1982年   3篇
  1981年   4篇
  1980年   2篇
  1978年   1篇
  1977年   5篇
  1976年   4篇
  1975年   3篇
排序方式: 共有296条查询结果,搜索用时 15 毫秒
1.
OBJECTIVE: To verify the feasibility and compare the results of thoracoscopic sympathectomy under local anaesthesia (LA) and spontaneous breathing vs. general anaesthesia (GA) with one-lung ventilation. METHODS: Two groups of consecutive patients underwent one stage bilateral T2-T3 thoracoscopic sympathectomy under LA (n=15) and GA (n=30) by the same surgical team for treatment of primary palmar hyperhidrosis. The groups were homogeneous for relevant demographic, physiological and clinical data, including pulmonary function. In both groups, patient's satisfaction was evaluated 24h after surgery by a simple interview and scored into five grades (1=very poor to 5=excellent), while quality of life (QOL) was evaluated by SF-36 and Nottingham's Health Profile questionnaires before and 6 months after surgery. A cost comparison between groups concerning devices, drugs, global in operating room time, medical personnel and hospital stay was also carried out. RESULTS: No operative mortality was recorded. The overall in operating room time for the whole bilateral procedure under LA was 63.55+/-10.58 vs. 86.05+/-5.75 under GA (P<0.01) and temperature increased in all patients from a baseline of 25.42+/-0.56 up to 32.15+/-0.84 degrees C. All patients undergone LA were discharged the same day after a chest roentgenogram and a short stay in the outpatient clinic. Among them three patients (20%) experienced a minimal (<30%) pneumothorax that required no treatment, while five (33.3%) had a trunk compensatory sweating that spontaneously resolved on the long run. Patients undergoing GA were discharged after a mean stay of 1.38+/-0.6 days. Among these, eight (26.6%) had prolonged trunk compensatory sweating that did not persist longer than 3 months. At a follow-up of 7.16+/-2.97 months, QOL was significantly improved with no difference between groups. The overall rate of satisfaction was greater in the LA group (P<0.05). CONCLUSIONS: In our study, awake one stage bilateral thoracoscopic sympathectomy for palmar hyperhidrosis could be safely and effectively performed as an outpatient procedure in patients refusing GA. Postoperative quality of life was equal to that in patients undergone the same procedure under GA, while patient satisfaction was better and cost were significantly reduced.  相似文献   
2.
苗慧  肖文彬  秦伯益 《药学学报》1990,25(9):646-651
本实验观察了MHDF对整体大鼠血流动力学和离体大鼠胸主动脉的作用。结果表明iv MHDF(3~12.8 mg/kg)能降低大鼠左心室±dp/dtmax,Vmax,Vpm和LVSP,延长T-dp/dtmax,减慢心率。MHDF还能舒张大鼠胸主动脉,ED50为6.5×10-6mol/L;非竞争拮抗NA和CaCl2致主脉收缩,pD2′为3.11±0.21和3.73±0.07;抑制高K+致主动脉收缩,IC50为1.76×10-5mol/L。提示MHDF对血管的作用与α受体阻断剂不同,而可能与钙拮抗有关。  相似文献   
3.
4.
Thin descending limb cells from Henle's loop (from the inner strip of the outer medulla of long loops) were studied with optical and video techniques to identify the mechanisms of ion transport and cell volume regulation. Increasing the K+ concentration in the basolateral solution from 5 to 90 mM caused the cells to swell. This K+-induced swelling was inhibited by exposure of the basolateral membrane to 9 mM Ba2+ and was abolished by removing Cl- from the perfusion solutions. Decreasing the perfusion osmolality caused an increase in cell volume followed by a return to the preexposure volume. The latter regulatory decrease in hypoosmolality was slowed by basolateral Ba2+ and the removal of HCO-3 from the solutions. Further slowing occurred when both HCO-3 and Cl- were removed. Exposure of cells to ouabain abolished volume regulation. These data suggest that the basolateral cell membrane of the thin descending limb has a Cl- -dependent K+ permeability, which is important in cell volume regulation. The cells also possess Cl- and HCO-3 transport pathways that participate in volume regulation. Finally, volume regulation is dependent upon the operation of the Na/K pump.  相似文献   
5.
6.
Lipoxygenase metabolites influence ion movement and fluid balance in the airways. We studied the effects of nordihydroguaiaretic acid (NDGA), a general inhibitor of the lipoxygenase pathway, on Na+ and Cl- secretion in cultured tracheal epithelial cells from adult rabbits through short-circuit current (Isc) and radioactive tracer flux experiments. NDGA inhibition of leukotriene release in freshly isolated rabbit tracheal epithelial cells was assayed by a 3H peptidyl-leukotriene radioimmunoassay. 3 microM NDGA resulted in a 91% reduction of leukotriene release. In unstimulated cultures, Cl- secretion (furosemide-inhibited fraction of Isc) was 11.1 +/- 2.8 muamp/cm2 (n = 10) and was unchanged in the presence of NDGA (n = 10). Epinephrine-stimulated Cl- secretion increased Isc by 12.2 +/- 2 muamp/cm2 (n = 10). This stimulation was unchanged by pretreatment with NDGA (n = 10), suggesting that inhibition of the lipoxygenase pathway did not affect Cl- secretion. In unstimulated cultures, Na+ absorption (amiloride-inhibited portion of Isc) was 10.7 +/- 3.3. muamp/cm2 (n = 10) and was reduced by 79% in the presence of NDGA (n = 10), suggesting that inhibition of the lipoxygenase pathway was associated with inhibition of Na+ absorption. Radioactive tracer flux experiments supported these findings. Exogenous LTD4 (n = 7) and LTC4 (n = 7) were added to cells pretreated with NDGA, and Na+ absorption was restored to 76% and 70% of control, respectively. In addition, LTD4 (n = 4) and LTC4 (n = 4) were added to cells without prior inhibition of the lipoxygenase pathway to NDGA and resulted in an increase in Cl- secretion.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
7.
8.
The immune responses to an HIV-1 p55Gag vaccine encoded as a DNA chimera with the lysosomal associated membrane protein-1 (LAMP) have been examined for the effect of the addition of the inverted terminal repeat (ITR) sequences of the adeno-associated virus (AAV) to the DNA plasmid construct, and of packaging the LAMP/gag gene as a recombinant AAV vector (rAAV). DNA plasmids encoding Gag and the LAMP/Gag protein chimera were constructed in two vectors, the pcDNA3.1 and a corresponding plasmid containing the ITR sequences (pITR) flanking the expression elements of the plasmid, and the pITR LAMP/gag DNA plasmid was encapsidated in the rAAV vector. Human 293 cells transfected in vitro with LAMP/gag plasmids either in pcDNA3.1 or pITR produced much Gag protein in cell extracts (1.6 and 2.2 ng of Gag/mg of protein, respectively). The immune responses of mice to immunization with these constructs were examined under three protocols: DNA prime/DNA boost, DNA prime/rAAV boost, and a single rAAV immunization. The results demonstrated that under DNA prime/DNA boost protocol, the "naked" DNA vaccines encoding the LAMP/gag chimera, either as pcDNA3.1 or pITR DNA plasmid constructs, elicited strong CD4(+) T cell responses. In contrast, significantly higher levels of CD8(+) and antibody responses were observed with the pITR-DNA constructs. Immunization with the rAAV vector under the DNA prime/rAAV boost protocol resulted in sustained T cell responses and a markedly increased antibody response, predominantly of the IgG(1) isotype resulting from the activation of the Th2 subset of CD4(+) T cells, that was sustained for at least 5 months after immunization.  相似文献   
9.
Previous studies have shown that the mRNA of cyclic-nucleotide-gated nonselective cation (CNG) channels is expressed in rat airway epithelia and that these channels contribute to sodium-mediated short-circuit currents in cultured rat tracheal epithelia. Patch-clamp studies from human A549 cells indicate that these channels contribute to cGMP-stimulated L-cis-diltiazem- and dichlorobenzamil-inhibited whole-cell sodium currents. This study demonstrates that mRNA for primary and secondary subunits of CNG channels, halphaCNG1 and hbetaCNG1 respectively, are expressed in several human airway cell lines, including normal and cystic fibrosis bronchial airway cells, in normal and cystic fibrosis tracheal airway cell lines and nasal polyp tissue from a cystic fibrosis patient. The mRNA of ralphaCNG1 in rat lung increased in response to increased circulating glucocorticoids and decreased in animals with lowered circulating glucocorticoids after aminoglutethimide treatment. Likewise the mRNA of halphaCNG1 increased in the presence of glucocorticoids in cultured alveolar airway cells. The mRNA of alphaCNG1 in rat lung was also increased in response to a low-salt diet and lowered in animals fed a high-salt diet. Likewise the mRNA of alphaCNG1 was increased in response to increased aldosterone and decreased in animals given spironolactone. These results suggest that mRNA for alphaCNG1 increases in response to elevated glucocorticoids or mineralocorticoids. Because alphaCNG1 is a functional sodium entry channel in both rat and human airway epithelial cells, if channel protein is also elevated this channel could mediate an increase in sodium absorption across lung epithelia in response to circulating hormones.  相似文献   
10.
0 引言为了克服离子选择电极(ISE)法的微量电位信号极易受环境温度变化及电子噪声的干扰问题,该仪器采用了参考电极,把参考电极与其测定电极装在同一测量室内,保持其相同的物理环境,使干扰源对所有电极的影响相同. 以内参液作为参考电极的测量对象,测得一个参考电极电位值,再测样品的电极电位值,二者相抵就消除了所叠加的干扰信号.  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