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   2134篇
  免费   160篇
  国内免费   17篇
耳鼻咽喉   4篇
儿科学   119篇
妇产科学   27篇
基础医学   196篇
口腔科学   53篇
临床医学   186篇
内科学   333篇
皮肤病学   54篇
神经病学   94篇
特种医学   217篇
外科学   393篇
综合类   165篇
一般理论   1篇
预防医学   149篇
眼科学   11篇
药学   155篇
中国医学   39篇
肿瘤学   115篇
  2022年   17篇
  2021年   31篇
  2020年   24篇
  2019年   28篇
  2018年   32篇
  2017年   24篇
  2016年   33篇
  2015年   35篇
  2014年   51篇
  2013年   71篇
  2012年   93篇
  2011年   101篇
  2010年   102篇
  2009年   86篇
  2008年   83篇
  2007年   78篇
  2006年   83篇
  2005年   76篇
  2004年   58篇
  2003年   60篇
  2002年   41篇
  2001年   45篇
  2000年   61篇
  1999年   56篇
  1998年   62篇
  1997年   79篇
  1996年   64篇
  1995年   52篇
  1994年   39篇
  1993年   40篇
  1992年   32篇
  1991年   28篇
  1990年   36篇
  1989年   62篇
  1988年   43篇
  1987年   40篇
  1986年   29篇
  1985年   29篇
  1984年   26篇
  1983年   13篇
  1982年   23篇
  1981年   19篇
  1980年   24篇
  1979年   23篇
  1978年   25篇
  1977年   17篇
  1976年   19篇
  1975年   15篇
  1974年   15篇
  1972年   10篇
排序方式: 共有2311条查询结果,搜索用时 15 毫秒
51.
目的探讨家庭雾化吸入治疗反复喘息患儿的疗效。方法前瞻性分析2012-2013年住院治疗的反复喘息患儿316例,按照是否进行家庭雾化规范治疗分为家庭雾化吸入组和非家庭雾化吸入组。观察家庭雾化吸入治疗反复喘息患儿,能否降低再次住院率、应用全身糖皮质激素及抗生素使用率。结果家庭雾化吸入组198例,随访1年当中其再次住院率为20.2%,门急诊就诊率为66.6%,应用全身糖皮质激素16.6%,应用抗生素65.6%,有症状天数14±5.2天,明显低于非家庭雾化吸入组,差异有统计学意义(P0.05),而两组间一年的医疗费用无统计学差异(P0.05)。结论家庭雾化吸入治疗,可降低反复喘息患儿再次住院率、门急诊就诊率、有症状天数及应用全身糖皮质激素、抗生素治疗次数而一年的医疗费用无增加。  相似文献   
52.
BACKGROUND: Tissue transglutaminase is now recognized as the autoantigen for antiendomysial antibodies. Antibodies to tissue transglutaminase have been proposed as a valuable test for coeliac disease. OBJECTIVE: To determine the value of antibodies to tissue transglutaminase in the diagnosis of coeliac disease in our outpatient population. METHODS: Patients who underwent serological tests for coeliac disease during the first 18 months of the tissue transglutaminase antibody assay were retrospectively identified from the regional serology laboratory database. Patients' symptoms were noted, along with serological results and duodenal histology in those patients who underwent duodenal biopsy.RESULTS In total, 586 patients were identified as having been serologically tested for coeliac disease, of whom 92 patients (33 men; mean age 51.7 years) had been followed up with duodenal biopsies. Of these 92 patients, 29 (31%; 14 men; mean age 52.5 years) had histological features of coeliac disease. The 63 patients with normal histology (19 men; mean age 51.8 years) acted as controls. Weight loss was more frequent in coeliac disease patients compared to controls (7 vs 5; P = 0.04) whereas the frequency of anaemia (P = 0.85) and diarrhoea (P = 0.74) did not differ significantly between the two groups. The sensitivity and specificity of tissue transglutaminase antibodies (86%; 84%) were compared to those for antiendomysial antibodies (90%; 98%) and antigliadin antibodies (76%; 79%). CONCLUSIONS: The diagnostic value of tissue transglutaminase antibodies was intermediate between that of antiendomysial antibodies and antigliadin antibodies. However, duodenal biopsy remains the gold standard diagnostic test for coeliac disease.  相似文献   
53.
Chesterman  CN; Owe-Young  R; Macpherson  J; Krilis  SA 《Blood》1986,67(6):1744-1750
Interactions between vascular endothelial cells and blood platelets have been investigated using a model microcirculation consisting of microcarrier beads colonized with human umbilical vein endothelial cells (HUVECs) and perfused with washed platelet suspensions. To simulate the effects of endothelial desquamation and exposure of subendothelium, fibrillar collagen in suspension was coinjected with the platelets. In this model, neither the passage of platelets alone nor collagen alone stimulated prostacyclin (PGI2) production by the HUVECs. Platelets activated by coinjection with collagen released thromboxane A2 (TXA2), and this was associated with the simultaneous production of PGI2 by the HUVECs. By means of double-isotope experiments with [3H]arachidonic acid (AA) incorporated into platelets and [14C]-AA into HUVECs, it was shown that all the PGI2 generated was derived from platelet AA and/or endoperoxides. This interpretation was strengthened by the finding that PGI2 production was not prevented by treatment of HUVECs with indomethacin followed by perfusion with collagen-stimulated platelets. AA metabolites in double-isotope label experiments were further characterized by reverse-phase chromatography, and it was shown that both cyclooxygenase and lipoxygenase products of the HUVECs were derived from platelet membrane lipid. Thrombin regularly produced transient PGI2 release, but showed rapid tachyphylaxis. Platelet-derived compounds including ADP, ATP, and platelet-activating factor (PAF) did not produce PGI2 release by HUVECs in this system. Thus, the transfer of AA and metabolites from collagen- stimulated platelets is likely to be the mechanism for PGI2 production in the context of minor degrees of endothelial desquamation.  相似文献   
54.
55.
56.
The objective is to estimate the risk of breast cancer in women who carry a deleterious BRCA1 or BRCA2 mutation, according to parental origin of mutation. We conducted a cohort study of women with a BRCA1 mutation (n = 1523) or BRCA2 mutation (n = 369) who had not been diagnosed with breast or ovarian cancer. For each woman, the pedigree was reviewed and the origin of the mutation was assigned as probable paternal or maternal. The hazard ratio (HR) for developing breast cancer in the follow‐up period was estimated for women with a paternal mutation compared to a maternal mutation. The risk of breast cancer was modestly higher in women with a paternal BRCA1 mutation compared to women with a maternal BRCA1 mutation (HR = 1.46; 95% CI = 0.99–2.16) but the difference was not significant (p = 0.06). The parental mutation origin did not affect the risk in women with a BRCA2 mutation. Our results are consistent with the hypothesis that there is an increased risk of breast cancer among women with a paternally inherited BRCA1 mutation compared to a maternally inherited mutation. However, the data are not sufficiently compelling to justify different screening recommendations for the two subgroups.  相似文献   
57.
Hereditary hemochromatosis (HH) is a common preventable disorder of iron overload that can result in liver cirrhosis and reduced lifespan. Most HH is due to homozygosity for the HFE p.C282Y substitution. We conducted a study of screening for p.C282Y in high schools where p.C282Y heterozygotes (CY) individuals were informed of their genotype by letter. We studied whether these individuals understood the implications of their genotype, whether this resulted in anxiety or reduced health perception and whether cascade testing was higher in families of CY than wild‐type homozygous (CC) individuals. We found 586 of 5757 (1 in 10) screened individuals were CY. One month after receiving their result, 83% correctly answered that they have one copy of p.C282Y. There was no adverse change in anxiety or health perception from prior to screening to 1 month after receiving results. Significantly more family members of CY individuals than CC individuals were informed about HH and had testing for HH. In conclusion, we found that informing CY individuals of their genotype does not increase anxiety and the implications are generally well understood. This leads to cascade testing in a minority of families. CY individuals should be informed of their genetic status when identified by population screening.  相似文献   
58.
59.
60.
Somatic cell hybrids derived from fusion of GM637, a human cell line transformed by simian virus 40, and mouse B82 cells were examined for simian virus 40 T antigen, V antigen, and viral DNA. All hybrid cell lines that contained viral DNA were T-antigen positive. Cells that did not have viral DNA were T-antigen negative. We determined that there is a single viral insertion in these hybrid cells. Correlation of T-antigen expression and viral DNA with the partial complements of the human genome retained in the hybrids shwed that the inserted viral genome is in human chromosome 8. The integrated viral DNA is stable; free viral DNA found in GM637 does not insert at other potential sites in the human genome.  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