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   2056篇
  免费   115篇
  国内免费   7篇
耳鼻咽喉   11篇
儿科学   81篇
妇产科学   34篇
基础医学   222篇
口腔科学   47篇
临床医学   271篇
内科学   432篇
皮肤病学   27篇
神经病学   48篇
特种医学   613篇
外国民族医学   1篇
外科学   161篇
综合类   40篇
预防医学   45篇
眼科学   18篇
药学   64篇
  1篇
肿瘤学   62篇
  2023年   7篇
  2022年   10篇
  2021年   14篇
  2020年   12篇
  2019年   14篇
  2018年   21篇
  2017年   19篇
  2016年   25篇
  2015年   44篇
  2014年   69篇
  2013年   70篇
  2012年   75篇
  2011年   75篇
  2010年   62篇
  2009年   83篇
  2008年   48篇
  2007年   82篇
  2006年   55篇
  2005年   55篇
  2004年   45篇
  2003年   44篇
  2002年   36篇
  2001年   33篇
  2000年   24篇
  1999年   37篇
  1998年   84篇
  1997年   85篇
  1996年   83篇
  1995年   65篇
  1994年   42篇
  1993年   60篇
  1992年   15篇
  1991年   28篇
  1990年   36篇
  1989年   61篇
  1988年   46篇
  1987年   50篇
  1986年   59篇
  1985年   73篇
  1984年   41篇
  1983年   35篇
  1982年   33篇
  1981年   32篇
  1980年   41篇
  1979年   13篇
  1978年   23篇
  1977年   25篇
  1976年   21篇
  1975年   22篇
  1967年   7篇
排序方式: 共有2178条查询结果,搜索用时 8 毫秒
991.
992.
993.
Carcinoid tumors: iodine-131 MIBG scintigraphy   总被引:2,自引:0,他引:2  
Eighty-two patients with pathologically proved carcinoid tumors were examined with iodine-131 metaio-dobenzylguanidine (MIBG) scintigraphy. Localization scores of I-131 MIBG accumulation in the primary tumor or metastatic site ranged from 0 to 3+ on the basis of comparison with normal liver. I-131 MIBG uptake varied greatly in different patients with carcinoid tumors. The localization scores in known tumor sites were related to the location of the primary tumor in the stomach (1-3+ in two of five patients), pancreas (1-3+ in four of five patients), cecum (3+ in two of two patients), appendix (0 in one of one patient), jejunum (0 in one of one patient), Meckel diverticulum (3+ in one of one patient), terminal ileum (2-3+ in 19 of 28 patients), bronchus (3+ in one of nine patients), thymus (1+ in one of two patients), and unknown (2-3+ in 18 of 28 patients). Tumors of midgut origin concentrated I-131 MIBG more frequently than those of foregut origin. Uptake of I-131 MIBG was more likely if neurohumor levels, particularly serum serotonin, were elevated. There was no relationship of I-131 MIBG uptake to carcinoid syndrome. I-131 MIBG is useful in the determination of the location and extent of some carcinoid tumors, particularly those of midgut origin.  相似文献   
994.
We tested the hypothesis that chronic graft-versus-host disease (GVHD) is due to inadequate thymic function by examining pretransplant serum levels of facteur thymique serique (FTS). Four of five patients with no detectable FTS activity developed chronic GVHD, while one of four with some FTS activity did. Further patient numbers are needed to confirm or reject this hypothesis. We further postulated that chronic GVHD, whatever its cause, involves thymic epithelium as a target organ. When tested 11 mo or more posttransplant, patients with chronic GVHD had lower absolute FTS levels (p less than 0.02) and lower age-corrected levels (p = 0.05) than patients without chronic GHVD. Low values in chronic GVHD were associated with the disease itself and not its therapy. These findings show that thymic epithelial secretory function is impaired in chronic GVHD, and this may in part be responsible for the immunodeficiency characteristic of these patients.  相似文献   
995.
996.
997.
Thirty-eight children between the ages of 0.8 and 17 years with acute nonlymphoblastic leukemia in first remission induced by chemotherapy were given cyclophosphamide, total body irradiation, and bone marrow transplants from HLA-matched donors. Six patients died of pneumonia, one died of metabolic problems, and one died of chronic graft-v-host disease complications. Five patients relapsed between six months and 3.2 years after transplantation. Three of the five died of leukemia, one survives with leukemia three years after transplantation, and one survives in remission off treatment following chemotherapy for 22 months. Twenty-five survive in continuous remission from 1.7 to 8.4 years after transplantation, and the actuarial analysis shows a disease- free survival rate of 64%, with a plateau extending from 3.5 to 8.4 years. All lead normal lives.  相似文献   
998.
It has been shown that in vivo and in vitro treatment with G-CSF induces the generation of low-density granulocytes (LDGs), which copurify with PBMCs and inhibit IFN-gamma production by human T cells. These results prompted us to postulate an immunomodulatory role for LDGs in acute graft-versus-host disease (aGVHD). Here it is shown that in the mouse experimental model, in vivo and in vitro G-CSF treatment generates LDGs capable of inhibiting 80% of T-cell IFN-gamma production. To assess the role of these LDGs in aGVHD, lethally irradiated (C57BL/6 x BALB/c) F1 hosts were reconstituted with T cell-depleted bone marrow cells plus nylon wool-purified spleen cells from G-CSF-treated (G-NWS) or -nontreated (NWS) C57BL/6 donors. Recipients of G-NWS had a 75% survival rate in contrast to a rate of 25% in the NWS recipients. The protective effect was completely abolished, and the mortality rate was 100% if donor-cell infusion was treated with anti-Gr1. Moreover, if LDGs were infused with NWS, full protection of aGVHD was observed, and no signs of disease were evidenced by mortality rate, weight loss, or histopathology of target organs. These results revealed the unexpected immunosuppressive capacity of G-CSF based on the generation of LDGs, leading to the possibility of using these cells as inhibitors of aGVHD.  相似文献   
999.
When acute renal vein thrombosis is associated with renal failure, aggressive therapy to eliminate the venous obstruction is indicated. There are reports of successful treatment of this condition with thrombolytic agents administered systemically or directly into the renal vein. Renal arterial administration of urokinase was used successfully to treat acute renal vein thrombosis associated with renal failure in a 9 1/2-year-old child.  相似文献   
1000.
The RET proto-oncogene encodes a transmembrane receptor with tyrosine kinase activity. Germline mutations in RET are responsible for a number of inherited diseases. These include the dominantly inherited cancer syndromes multiple endocrine neoplasia types 2A and 2B (MEN 2A and MEN 2B) and familial medullary thyroid carcinoma (FMTC), as well as some cases of familial Hirschsprung disease (HSCR1). RET mutations in HSCR1 have been shown to cause a loss of RET function, while the cancer syndromes result in RET oncogenic activation. Occasionally MEN 2A or FMTC occurs in association with HSCR1, albeit with low penetrance. An initial report linked HSCR1 in MEN 2A solely to the C618R and C620R RET mutations. In this study we have analyzed 44 families with MEN 2A. HSCR1 co-segregated with MEN 2A in seven (16%) of the 44 families. The predisposing RET mutation in all seven families had been previously reported in MEN 2A or FMTC and occurred in exon 10 at codons 609, 618 or 620, resulting in C609Y, C618S, C620R or C620W substitution. MEN 2A families with RET exon 10 Cys mutations had a substantially greater risk of developing HSCR1 than those with the more common RET exon 11 Cys634 or exon 14 c804 mutations (P = 0.0005). These findings suggest that expression of HSCR1 in MEN 2A may be peculiar to RET exon 10 Cys mutations . However, HSCR1 in MEN 2A is not exclusive to C618R or C620R RET mutations and can occur with other exon 10 Cys amino acid substitutions. The strong correlation between disease phenotype and position of the MEN 2A RET mutation suggests that oncogenic activation of RET alone is insufficient to account for co-expression of the diseases.   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