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   1028篇
  免费   52篇
  国内免费   5篇
耳鼻咽喉   3篇
儿科学   99篇
妇产科学   9篇
基础医学   95篇
口腔科学   19篇
临床医学   117篇
内科学   212篇
皮肤病学   32篇
神经病学   33篇
特种医学   128篇
外科学   121篇
综合类   39篇
预防医学   89篇
眼科学   30篇
药学   29篇
  1篇
肿瘤学   29篇
  2023年   6篇
  2022年   6篇
  2021年   18篇
  2020年   11篇
  2019年   13篇
  2018年   15篇
  2017年   8篇
  2016年   14篇
  2015年   20篇
  2014年   24篇
  2013年   28篇
  2012年   18篇
  2011年   24篇
  2010年   45篇
  2009年   36篇
  2008年   34篇
  2007年   55篇
  2006年   46篇
  2005年   41篇
  2004年   46篇
  2003年   37篇
  2002年   33篇
  2001年   27篇
  2000年   25篇
  1999年   27篇
  1998年   44篇
  1997年   53篇
  1996年   41篇
  1995年   22篇
  1994年   35篇
  1993年   24篇
  1992年   17篇
  1991年   16篇
  1990年   15篇
  1989年   30篇
  1988年   21篇
  1987年   10篇
  1986年   8篇
  1985年   6篇
  1984年   16篇
  1983年   14篇
  1982年   13篇
  1981年   11篇
  1980年   8篇
  1978年   3篇
  1977年   3篇
  1976年   4篇
  1969年   2篇
  1946年   2篇
  1921年   1篇
排序方式: 共有1085条查询结果,搜索用时 15 毫秒
971.
Malignant pleural mesothelioma has been considered a uniformly fatal disease associated with a median survival of 4 to 18 months. Extrapleural pneumonectomy alone has proved disappointing in the treatment of this disease, as have chemotherapy and radiotherapy. From 1980 to 1990, 31 patients with pleural mesothelioma underwent multimodality therapy that included extrapleural pneumonectomy with resection of the pericardium and diaphragm. The age of the patients was 53.4 +/- 8.6 years; 26 were male. All patients had the pathologic diagnosis reviewed before treatment. At thoracotomy six patients had residual (unresectable) gross disease, and in 23 there was histologic evidence of disease at the resection margin. The perioperative morbidity and mortality rates were 19% and 6%, respectively. The mean length of hospital stay for the 29 patients who survived the operation was 10.9 +/- 3.5 days. Postoperatively 26 patients received cyclophosphamide, doxorubicin, and cis-platinum chemotherapy with or without radiotherapy. The survival rates were 70% at 1 year and 48% at 2 years. Trends toward improved survival in the patients with complete resections approached but did not reach statistical significance. These data suggest that this multimodality protocol can be administered with acceptable morbidity and mortality. Prospective trials are justified to further clarify the role of this approach.  相似文献   
972.
Impedance aggregometry allows the measurement of platelet responses in whole blood as well as in PRP. The variability of haematocrit values encountered when applying this technique to haemodialysis patients prompted an investigation of the effects of red cells on platelet aggregation in whole blood. Collagen induced aggregation was measured in both PRP and whole blood from haemodialysis patients and healthy controls, Platelets from haemodialysis patients were less aggregable than those from the controls when tested in PRP, but more aggregable when tested in whole blood. Blood samples with a range of haematocrit values were prepared by mixing PRP and autologous red cells, and used to study the effect of haematocrit on platelet aggregation. In blood from control subjects aggregation rate was reduced by rising haematocrit but no reduction of maximum aggregation occurred until haematocrit exceeded 40%. In contrast uraemic platelets showed increased responses in the presence of red cells. In a limited cross-over study no significant difference was found in the effect on platelet aggregation of washed erythrocytes from uraemic and non-uraemic donors. It is concluded that red cell presence influences platelet aggregation by complex mechanisms during impedance aggregometry and that this effect must be considered when interpreting results.  相似文献   
973.
A new anaesthetic induction agent, propofol (Diprivan; Stuart), was used to induce anaesthesia in 16 healthy patients scheduled for minor gynaecological surgery. The findings were then compared with those in a subsequent group of 16 patients who received methohexitone for induction of anaesthesia. Halothane was used to maintain anaesthesia in all cases. Quality of induction, side-effects, cardiovascular indices, wake-up times and presence or absence of recall were recorded. Propofol caused fewer side-effects on induction and emergence and less change in heart rate than methohexitone, and patients were more clear-headed on awakening. Our findings indicate that propofol is a promising agent for induction of anaesthesia for day-case surgery.  相似文献   
974.
Lower extremity spiral CT angiography versus catheter angiography   总被引:15,自引:0,他引:15  
  相似文献   
975.
976.
OBJECTIVE: To investigate the maternal comprehension of two different growth charts and to identify the group of mothers with poor comprehension. DESIGN: An experimental prospective study. SETTING: A child welfare clinic at the De Soysa Hospital for Women, Colombo, Sri Lanka. SUBJECTS: 932 mothers were studied regarding their interpretation of the type of growth chart their infants had been allocated. A total of 413 mothers interpreted the 'road-to-health' chart and 519 mothers interpreted the revised chart. A validated scoring system was used to assess comprehension. The two groups of mothers were comparable. RESULTS: 62.4% (324) mothers who interpreted the revised chart had good comprehension. Only 20.6% (85) mothers had similar comprehension with the road-to-health chart. Education up to or beyond grade 8 in school significantly improved comprehension. CONCLUSION: The design of the growth chart has a powerful effect on maternal comprehension of growth patterns. Length of schooling rather than literacy alone is a marker of a comprehending mother. The policy implications of these findings are that governments and agencies may need to redesign parent held growth charts to achieve better comprehension by mothers.  相似文献   
977.
An important role for immunoglobulin M (IgM) during early acute virulent Toxoplasma gondii infection was identified using IgM-/- mice that lack surface and secretory IgM but maintain normal B-cell functionality and isotype class switching. Following intraperitoneal inoculation with the virulent RH strain, IgM-/- mice displayed significantly fewer peritoneal parasites than wild-type (WT) mice, which correlated with increased tachyzoite dissemination to the liver, lung, and spleen in IgM-/- mice compared with WT mice. Early splenic T-cell activation, as measured by CD69 expression, was augmented in IgM-/- mice, and serum and peritoneal cavity gamma interferon levels were also elevated in IgM-/- mice compared with WT controls. Consequently, the difference in parasite dissemination was not attributable to an impaired proinflammatory immune response in the IgM-/- mice. Specific IgM was found to bind to tachyzoites in vivo in WT mice, and this correlated with an increased ability of antiserum collected from WT mice at day 6 postinfection to block tachyzoite cell invasion, compared with comparable serum collected from IgM-/- mice at the same time point. Tachyzoite invasion of host cells was similar if parasites were incubated with WT or IgM-/- nonimmune serum, suggesting that natural IgM does not function to limit parasite dissemination during early T. gondii infection. Our results highlight an important role for parasite-specific IgM in limiting systemic dissemination of tachyzoites during early acute T. gondii infection.  相似文献   
978.
Strain-dependent vascular remodeling phenotypes in inbred mice   总被引:1,自引:0,他引:1       下载免费PDF全文
We have recently established a mouse model of arterial remodeling in which flow in the left common carotid artery of FVB mice was interrupted by ligation of the vessel near the carotid bifurcation, resulting in a dramatic reduction of the lumen as a consequence of a reduction in vessel diameter and intimal lesion formation. In the present study we applied this model to various inbred strains of mice. Wide variations in the remodeling response with regard to reduction in vessel diameter, intimal lesion formation, lumen area, and medial hypertrophy were found. On carotid artery ligation SJL/J mice revealed the most extensive inward remodeling leading to an approximate 78% decrease in lumen area while lumen narrowing in FVB/NJ mice was largely due to extensive neointima formation as a result of smooth muscle cell (SMC) proliferation. Significant positive remodeling in the contralateral right carotid artery with a >20% increase in lumen area was observed in SM/J and A/J mice. An in vitro comparison of growth properties of SMC isolated from FVB/NJ mice and a strain that exhibited very little SMC proliferation (C3H/HeJ) demonstrated accelerated growth of SMC from FVB/NJ following serum stimulation. In vivo, SMC proliferation in the FVB/NJ strain was preceded by a 37% loss of medial SMC occurring within the 2 days after ligation, however, cell death was not detectable in C3H/HeJ mice. These findings suggest that the mechanisms leading to lumen narrowing in the vascular remodeling process are genetically controlled.  相似文献   
979.
980.
We report a four-generation family, with five individuals affected by osteopathia striata with cranial sclerosis (OS-CS). The family illustrates the wide spectrum of gene expression in this autosomal dominant condition. Of particular note is the unusually severe expression in the proband, who exhibits virtually all of the reported associations of the syndrome. Proximal osteolysis of the fibula and congenital urological abnormalities, in the proband, and holoprosencephaly sequence, in the proband's sister, have not previously been described in the syndrome.  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