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   453篇
  免费   16篇
  国内免费   5篇
儿科学   39篇
妇产科学   2篇
基础医学   108篇
口腔科学   4篇
临床医学   51篇
内科学   111篇
皮肤病学   1篇
神经病学   31篇
特种医学   20篇
外科学   66篇
综合类   1篇
预防医学   3篇
眼科学   1篇
药学   25篇
肿瘤学   11篇
  2021年   2篇
  2020年   2篇
  2019年   4篇
  2017年   4篇
  2015年   3篇
  2014年   7篇
  2013年   7篇
  2012年   7篇
  2011年   12篇
  2010年   9篇
  2009年   8篇
  2008年   15篇
  2007年   19篇
  2006年   11篇
  2005年   19篇
  2004年   20篇
  2003年   26篇
  2002年   25篇
  2001年   23篇
  2000年   26篇
  1999年   16篇
  1998年   8篇
  1997年   9篇
  1996年   11篇
  1995年   13篇
  1994年   8篇
  1993年   8篇
  1992年   25篇
  1991年   20篇
  1990年   15篇
  1989年   12篇
  1988年   12篇
  1987年   10篇
  1986年   6篇
  1985年   8篇
  1984年   2篇
  1983年   5篇
  1982年   2篇
  1981年   3篇
  1980年   5篇
  1979年   3篇
  1978年   2篇
  1975年   2篇
  1974年   4篇
  1973年   3篇
  1972年   3篇
  1967年   1篇
  1966年   1篇
  1965年   1篇
  1917年   1篇
排序方式: 共有474条查询结果,搜索用时 15 毫秒
31.
Proliferative responses of cord blood lymphocytes (CBLs) to food antigens and cord blood IgE concentrations were measured in 37 full term newborn infants for the prediction of allergic disorders. In these 37 infants who were followed up for two years, allergic history of the family was found in four (sensitivity 57.1%) and cord blood IgE concentrations were greater than 0.5 IU/ml in three (sensitivity 42.9%) of seven infants who developed allergic disorders. When CBLs were stimulated twice by ovalbumin or bovine serum albumin, the value of the stimulation index in proliferative responses of CBLs to ovalbumin or bovine serum albumin was greater than 1.5 in six (sensitivity 85.7%) of seven infants who developed allergic disorders. The specificity of the responses of CBLs in the prediction of the development of allergic disorders was 93.3%. The proliferative responses of CBLs to food antigens were useful in the prediction of not only development of allergic disorders but also offending allergens. These observations provide further evidence that sensitisation is occurring in utero. This would appear to be increasingly important in the genesis of early atopic problems. As our follow up is only two years, in utero sensitisation is a prediction for the early development of atopic disease but only longer follow up will show whether this holds good for allergic disorders at any age.  相似文献   
32.
33.
We have found that peroxisome assembly is temperature-sensitive (ts) in mild forms of peroxisome biogenesis disorders (PBDs), that is all infantile Refsum disease (IRD) patients and a few neonatal adrenoleukodystrophy patients of several complementation groups. The number of peroxisomes increased daily in incubation at 30 degrees C in the ts cells. Oxidation of very long-chain fatty acids, processing of acyl-CoA oxidase and dihydroxyacetonephosphate acyltransferase activity also improved after 8 days incubation at 30 degrees C in the IRD fibroblasts. These biochemical functions of the peroxisome did not change at 30 degrees C in Zellweger fibroblasts. Number of peroxisomes gradually decreased after 4 days when the temperature shifted from 30 to 37 degrees C in the ts cells. These results indicate that the biochemical functions of peroxisome are also restored by incubation at 30 degrees C in the mild and ts phenotype of PBDs, and the results will aid to predict the severity and the prognosis of affected children.  相似文献   
34.
Terazawa S, Kondo N, Orii T. Significance of measurement of pre-S2 antigen for the prevention of vertical transmission of hepatitis B virus in infants born to HBsAg carrier mothers. Acta Pædiatr 1994;83:30–4. Stockholm. ISSN 0803–5253
The significance of pre-S2 antigen (pre-S2 Ag) as a marker of hepatitis B virus (HBV) infection, especially in infants born to HBsAg carrier mothers who are HBeAg-negative or HBeAg-positive, was evaluated. Pre-S2 Ag was measured by enzyme immunoassay. HBsAg carrier mothers who were HBeAg-negative and HBeAb-positive were divided into two groups: group A, mothers whose infants were not infected with HBV ( n = 10) and group B, mothers whose infants were infected with HBV ( n = 13). Absorption rates of pre-S2 Ag in group A and B were 0.09 k 0.04 and 1.36 ± 0.95, respectively. The values for pre-S2 Ag in group B were significantly higher than those in group A. Values for pre-S2 Ag among HBsAg carrier mothers who were HBeAg-positive and HBeAb-negative were also measured by reversc passive hemagglutination. In the same way, HBsAg carrier mothers who were HBeAg-positive and HBeAb-negativc were divided into two groups: group C, mothers whose infants did not become HBsAg carriers ( n = 15) and group D, mothers whose infants became HBsAg carriers (n = 11). The titers of pre-S2 Ag (reverse passive hemagglutination) in group C and D were 25.75 ± 1.68 and 210.45±1.69, respectively. The values for pre-S2 Ag in group D were significantly higher than those in group C. The values for pre-S2 Ag as markers of infectivity became higher with increasing amounts of HBV-DNA. Therefore, our results show that measurement of pre-S2 Ag in HBsAg carrier mothers who are HBeAg or HBeAb-positive is useful in the detection of high-risk groups of vertical transmission of HBV.  相似文献   
35.
36.
OBJECTIVE: Leiomyosarcoma of the uterus is a rare smooth muscle tumor; it is extremely malignant and the rates of local recurrence and metastasis are high. Since tumor suppressor genes are commonly altered in malignant tumors, it is possible that mutations in such genes are involved in the development of uterine leiomyosarcoma. METHODS: Fifty-five patients (37-70 years of age) diagnosed as having smooth muscle tumors of the uterus were selected. DNA was extracted from four or five 8-microm-thick consecutive tissue sections of each smooth muscle tumor from the paraffin-embedded blocks. Loss of heterozygosity (LOH) was investigated at nine loci within or close to tumor suppressor genes (TP53, RB1, DCC, NM23, WT1, D14S267, P16, DPC4, PTCH). RESULTS: Nineteen of twenty leiomyosarcomas revealed at least one instance of LOH among eight of the nine markers tested (one locus showed no LOH at all). In fact, 11 of the 20 cases exhibited two or more instances of LOH and, of the remaining 9 cases, 4 showed a point mutation of p53 in addition to an alteration in one of the 9 markers, while one exhibited a p53 mutation only. CONCLUSION: An accumulation of genetic alterations among tumor suppressor genes may play a key role in the tumorigenesis and progression of uterine leiomyosarcoma.  相似文献   
37.
Mitochondrial acetoacetyl-CoA thiolase (T2) deficiency is an inherited metabolic disorder of isoleucine and ketone body catabolism. We report the cases of two siblings who showed clinically mild forms of this disorder. They did not excrete tiglylglycine in urine. Their EB-transformed lymphocytes contained residual T2 activity, which was confirmed by immunotitration analysis. In immunoblot analysis, the bands corresponding to T2 in the samples of the cell lines from two patients were the most intensely detected among those from 19 T2-deficient cell lines tested  相似文献   
38.
39.
The diffusion-weighted magnetic resonance (MR) imaging characteristics of chronic subdural hematoma and the correlation between hematoma liquidity and apparent diffusion coefficient (ADC) were investigated in 26 consecutive patients, 16 males and 10 females aged 42 to 92 years (mean +/- SD 73.3 +/- 13.1 years), with 31 chronic subdural hematomas. The chronic subdural hematomas were divided into homogeneous, separate, and trabecular types based on diffusion-weighted MR imaging findings. Almost all hematomas were low intensity on diffusion-weighted imaging, and the mean ADC value was 1.81 +/- 0.79 x 10(-3) mm2/sec. The high intensity areas in the subdural hematomas consisted of several types: high intensity line along the dura mater (subdural hyperintense band), high intensity along the intrahematoma septum, and laminar shape along the inner membrane. The subdural hyperintense bands accounted for almost all high intensity areas in the subdural hematomas. The mean ADC value of the high intensity areas was 0.76 +/- 0.24 x 10(-3) mm2/sec, close to that of the normal brain. The subdural hyperintense bands were considered to be intracellular and/or extracellular methemoglobin based on the T1- and T2-weighted imaging and intraoperative findings. The subdural hyperintense band is an important finding indicating relatively fresh bleeding from the outer membrane. Diffusion-weighted imaging shows liquid subdural hematoma as low intensity, and measurement of the ADC values can differentiate between liquid and solid components of the chronic subdural hematoma.  相似文献   
40.
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