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   870篇
  免费   34篇
  国内免费   3篇
儿科学   72篇
妇产科学   11篇
基础医学   73篇
口腔科学   25篇
临床医学   80篇
内科学   212篇
皮肤病学   21篇
神经病学   16篇
特种医学   250篇
外科学   38篇
综合类   10篇
预防医学   31篇
眼科学   4篇
药学   26篇
中国医学   1篇
肿瘤学   37篇
  2023年   2篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2018年   11篇
  2017年   9篇
  2016年   7篇
  2015年   10篇
  2014年   15篇
  2013年   14篇
  2012年   14篇
  2011年   6篇
  2010年   33篇
  2009年   38篇
  2008年   21篇
  2007年   13篇
  2006年   16篇
  2005年   11篇
  2004年   10篇
  2003年   13篇
  2002年   7篇
  2001年   8篇
  2000年   4篇
  1999年   11篇
  1998年   49篇
  1997年   65篇
  1996年   49篇
  1995年   40篇
  1994年   50篇
  1993年   51篇
  1992年   9篇
  1991年   10篇
  1990年   10篇
  1989年   36篇
  1988年   39篇
  1987年   28篇
  1986年   28篇
  1985年   26篇
  1984年   11篇
  1983年   21篇
  1982年   17篇
  1981年   18篇
  1980年   21篇
  1979年   3篇
  1978年   8篇
  1977年   12篇
  1976年   9篇
  1975年   17篇
  1973年   1篇
  1948年   1篇
排序方式: 共有907条查询结果,搜索用时 15 毫秒
841.
We report here the results of a phase I clinical trial using counterflow centrifugal elutriation (CCE) for the removal of donor T lymphocytes before allogeneic bone marrow transplantation (BMT). Thirty- eight patients received lymphocyte-depleted allografts from HLA- identical, MLR-nonreactive sibling donors. The patients entered onto the study were either at high risk on the basis of age (median, 39 years) or disease status (acute leukemia in early relapse [ER], chronic myelogenous leukemia [CML] in accelerated phase [AP], or therapy resistant [RES] lymphoma). All patients received a standard lymphocyte dose of 1 x 10(6) morphologic lymphocytes per kilogram ideal body weight (BW) and were maintained on cyclosporine A (CsA) for 170 days after BMT. Prompt engraftment occurred in 37 of 38 patients with a median time to absolute neutrophil count (ANC) greater than 500/microL of 18 days. Although acute graft-v-host disease (GVHD; clinical stage I or greater) was observed in 45%, it was limited to the skin in all but five patients. Survival was related to disease status at the time of BMT. Among patients with acute leukemia in first or second remission, CML in chronic phase (CP) or lymphoma in partial remission (PR), 64% are currently alive, in contrast to 31% of patients with acute leukemia in third remission or early relapse, CML in second CP or AP, or RES lymphoma. Median follow-up for all patients was 351 days (range, 105 to 711 days). We conclude that this procedure is safe and warrants further evaluation in a randomized efficacy trial.  相似文献   
842.
843.
本文通过乳糖干扰下扑尔敏的含量测定,主要探讨及考察了非专属的一般操作误差对方法的正确评价和比较的影响,提出了检查一般操作误差大小的方法,进一步确认了吸收度线性组合法的优越性。同时讨论了吸收度线性组合法的组合精度与组合点数之间的关系,以及主组分吸收度过小对测定精度的影响,考察了吸收度比值在确定组合方式中的重要性。  相似文献   
844.
The abnormal prostate: MR imaging at 1.5 T with histopathologic correlation   总被引:4,自引:0,他引:4  
Carrol  CL; Sommer  FG; McNeal  JE; Stamey  TA 《Radiology》1987,163(2):521-525
Thirteen patients with biopsy-proved adenocarcinoma were prospectively examined with magnetic resonance (MR) imaging with use of a 1.5-T superconducting magnet. All patients subsequently underwent radical prostatectomy and careful, axial, histologic mapping of prostatic disease. Histologic findings were recorded on serial, axial diagrams to ensure precise pathologic correlation with the MR images. MR permitted identification of eight of 12 (67%) adenocarcinomas as hypointense foci (relative to the surrounding, higher intensity, peripheral zone); but tumor volume was under-estimated with MR imaging in five of eight cases (63%). Nodules of prostatic hyperplasia were identified correctly in only one of nine patients (11%). These findings suggest that, despite that fact that high field strength MR imaging currently does not depict all pathologic foci within the prostate, it may be of predictive value in the differential diagnosis of prostatic abnormalities when their locations are demonstrable.  相似文献   
845.
Tanner  JE; Menezes  J 《Blood》1994,84(11):3956-3964
Posttransplant patients undergoing prolonged cyclosporine A (CsA) immunosuppressive therapy have been reported to have increased incidence of Epstein-Barr virus (EBV)-associated lymphoproliferative disorders. We undertook experiments to analyze the possible actions of CsA during EBV-infection of human peripheral blood mononuclear cells (PBMC). EBV-infected B cells cultured with CsA demonstrated increased EBV B-cell outgrowth as compared with those cultured without CsA. PBMC, after infection with EBV and CsA treatment, demonstrated increased interleukin-6 (IL-6) activity in the culture supernatant. The induction of IL-6 appears to differ within the various lymphocyte populations. In monocytes, IL-6 expression appears preferentially induced by EBV and is initiated by the binding of the two major virion glycoproteins, gp350 and gp220. Expression of IL-6 in T cells appears to be due mainly to CsA. B cells also express IL-6 after EBV exposure, but not after CsA treatment. EBV-immortalized B-cell lines cultured with CsA exhibited both an increased number of cells expressing viral lytic-cycle antigens and increased amounts of lytic-cycle proteins. IL-6, which is induced by CsA in PBMC, was also capable of inducing the lytic viral cycle in several EBV-immortalized cells. CsA, in promoting both increased numbers of lytic EBV B cells and an EBV paracrine factor, IL-6, within the microenvironment of EBV B cell:T cell and EBV B cell:monocyte interactions, may result in increased EBV B-cell immortalization and ultimately lead to the promotion of B-cell lymphomas in immunosuppressed patients.  相似文献   
846.
Dion  JE; Rankin  RN; Vinuela  F; Fox  AJ; Wallace  AC; Mervart  M 《Radiology》1986,160(3):717-721
The radiologic and pathologic effects of canine renal embolization with dextran microspheres of two size ranges (40-150 micron and 100-300 micron) were studied 30 minutes and 1, 2, 4, and 6 weeks after embolization. Dramatic occlusions occurred with very small quantities of these particles, which reached more distally and were suspended and embolized more easily than other solid embolic agents. Because of these qualities, however, they should be used with more caution. They can be injected through 2-F catheters, calibrated-leak balloons, and open-ended guide wires. Embolization with dextran microspheres was also used for epistaxis, meningioma, dural arteriovenous malformation, renal tumors, bone metastasis, multiple myeloma, or peripheral angioma in ten patients. The technique was safe and effective, but special attention should be directed to proper dilution and gentle embolization with careful monitoring to avoid excessive embolization or reflux.  相似文献   
847.
JE Gronbech  ER Lacy 《Gastroenterology》1996,111(6):1474-1483
BACKGROUND & AIMS: Gastric mucosal hyperemia is a protective response mediated at least in part by the response of sensory afferent neurons to hydrogen ions. The aim of this study was to determine if other pathways to the hyperemic response are present and if these neurons have an effect exclusive of hyperemia on mucosal protection and repair. METHODS: Rat sensory afferent neurons were ablated by capsaicin treatment. Chambered stomachs were damaged by hypertonic saline followed by either acidic or neutral isotonic saline. Blood flow was measured by laser Doppler velocimetry, and mucosal morphology was quantitatively evaluated by microscopy. RESULTS: Mucosal damage alone evoked a strong hyperemic response in both control and ablated rats. Ablated rats lost gastric protection despite this hyperemic response. Acid exposure after damage sustained the hyperemic response. Rapid epithelial restitution occurred faster (even over hemorrhagic lesions) in control rats. CONCLUSIONS: The hyperemic response to mucosal damage alone is not mediated by sensory neurons. Protection of the stomach by sensory afferent neurons occurs by mechanisms also unrelated to their elicitation of hyperemia. Restitution during acid challenge is enhanced by the sustained hyperemic response mediated through sensory afferent neurons. (Gastroenterology 1996 Dec;111(6):1474-83)  相似文献   
848.
Fracture nonunion: CT assessment with multiplanar reconstruction   总被引:2,自引:0,他引:2  
Nineteen patients with suspected or possible fracture nonunion underwent computed tomography (CT) with multiplanar reconstruction (MPR). Each case represented a difficult problem in fracture management in which clinical and conventional radiographic examinations had failed to provide a definitive diagnosis. CT with MPR demonstrated nonunion in 13 of 19 cases by delineating the lack of bone bridging across the fracture site in multiple planes. Variable amounts bridging were detected in six cases, indicating partial healing or delayed union. Evaluation of fracture healing with MPR was possible despite remaining metal hardware (ten cases), multiple operations (15 cases), or bone grafting (five cases). CT with MPR aided surgical planning and affected treatment options by providing a more detailed assessment of malalignment and angular deformities, the magnitude of the gap in bone, and the integrity of the adjacent weight-bearing joints in multiple projections. It is an important new modality for evaluating fracture nonunion.  相似文献   
849.
A predictable increase in the proliferative rate of malignant cells remaining after initial cytoreduction in vivo forms the rationale for timed sequential therapy (TST) with 1-B-D-arabinofuranosylcytosine (ara- C) for adult acute myelogenous leukemia (AML). The relationship between in vivo leukemic cell growth, intracellular ara-C metabolism, and clinical response to ara-C-containing TST was evaluated by comparing AML marrow cell growth kinetic and biochemical pharmacologic determinants obtained before therapy (day 0) and at the predicted peak of in vivo postdrug residual tumor proliferation (day 8). Serial measurements of DNA synthesis and net intracellular ara-C metabolism demonstrated marked increases in both determinants in day 8 residual tumor when compared with the pretreatment cells for newly diagnosed adults achieving complete remission but not for TST-refractory patients. The interrelationship of AML cell proliferation and biochemical pharmacology together quantitate cytotoxicity measured by both achievement and duration of remission and serve to predict eventual clinical outcome in response to TST with ara-C where both growth and favorable pharmacokinetics are intrinsic to the success of the drug schedule.  相似文献   
850.
Left azygos lobe   总被引:1,自引:0,他引:1  
Takasugi  JE; Godwin  JD 《Radiology》1989,171(1):133-134
Left azygos lobe is much rarer than right azygos lobe, but cases have been reported. Computed tomography proved more reliable than plain radiography in the diagnosis of left azygos lobe in a 10-year-old girl.  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