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   465篇
  免费   99篇
  国内免费   6篇
耳鼻咽喉   1篇
儿科学   31篇
妇产科学   7篇
基础医学   60篇
口腔科学   8篇
临床医学   40篇
内科学   125篇
皮肤病学   10篇
神经病学   23篇
特种医学   89篇
外科学   55篇
综合类   14篇
预防医学   36篇
眼科学   13篇
药学   40篇
肿瘤学   18篇
  2021年   2篇
  2019年   3篇
  2018年   8篇
  2017年   3篇
  2016年   6篇
  2015年   7篇
  2014年   4篇
  2013年   15篇
  2012年   4篇
  2011年   2篇
  2010年   15篇
  2009年   15篇
  2008年   10篇
  2007年   12篇
  2006年   15篇
  2005年   9篇
  2004年   6篇
  2003年   7篇
  2002年   13篇
  2001年   10篇
  2000年   3篇
  1999年   16篇
  1998年   27篇
  1997年   30篇
  1996年   36篇
  1995年   30篇
  1994年   34篇
  1993年   21篇
  1992年   14篇
  1991年   7篇
  1990年   12篇
  1989年   17篇
  1988年   12篇
  1987年   15篇
  1986年   17篇
  1985年   22篇
  1984年   14篇
  1983年   7篇
  1982年   5篇
  1981年   11篇
  1980年   9篇
  1979年   4篇
  1978年   5篇
  1977年   6篇
  1976年   11篇
  1975年   4篇
  1974年   2篇
  1971年   3篇
  1968年   2篇
  1955年   1篇
排序方式: 共有570条查询结果,搜索用时 33 毫秒
91.
The effects of acute normovolemic hemodilution on hemodynamics, oxygen transport, tissue perfusion and blood volume were studied. The subjects were four patients undergoing total hip replacement with prebleeding and hemodilution under fluoroxene and nitrous oxide anesthesia. The hematocrit was reduced to 29% and 21% by bleeding in two steps with simultaneous infusion of plasmanate and lactated Ringer's solution. The major compensation was a rise in CO to 123% and 136%. Systemic oxygen transport (COX arterial O(2) content) was only slightly reduced and the arteriovenous oxygen difference decreased. Tissue perfusion remained excellent. Blood volume was slightly expanded. The procedure was well tolerated by this group of selected patients, and homologous blood utilization was markedly reduced.  相似文献   
92.
93.
94.
Demographic and symptomatic data gathered from 460 patients referred for lumbosacral CT examinations were analyzed to determine if the prescan probability of normal or abnormal findings could be predicted accurately. We were unable to predict the presence of herniated disk on the basis of patient-supplied data alone. Age was the single most significant predictor of an abnormality and was sharply related to degenerative disease and spinal stenosis.  相似文献   
95.
SUMMARY: Transforming growth factor-β (TGF-β) has been considered the principal cytokine involved in the pathogenesis of renal fibrosis. In the present study, we evaluated TGF-β activity in occasional samples from 22 normal individuals and 29 patients (11 with focal glomerulosclerosis, 11 with membranous nephropathy, five with Berger disease, one with type I membranoproliferative glomerulonephritis and one with postinfectious glomerulonephritis) using a CCL-64 mink lung cell growth inhibition assay.
A significantly increased urinary TGF-β activity (reported in relation to urine creatinine, Ucreat, and median) was observed in patients with glomerulonephritis compared with normal individuals ( P <0.01). the patients with Berger disease [median (Md) = 9.96/10 μg Ucreat.], membranous glomerulonephritis (Md = 7.23/10 μg Ucreat.) and focal glomerulosclerosis (Md = 16.6/10 μg Ucreat.) showed higher urinary TGF-β than normal individuals (Md = 1.09/10 μg Ucreat.) ( P <0.01). We found a positive correlation between the TGF-β activity in the urine of these patients and the incidence of segmental glomerulosclerosis ( r = 0.45, P <0.05) and their plasma creatinine levels ( r = 0.87, P <0.01). A negative correlation was observed between the TGF-β activity in the urine of these patients and their creatinine clearance ( r =−0.75, P <0.01).
Our data suggest that measurement of urinary TGF-β activity could be a useful non-invasive procedure for the evaluation of renal TGF-β production, permitting the assessment of prognosis and the evaluation of therapeutic efficacy in patients with renal disease.  相似文献   
96.
Egesten  A; Calafat  J; Knol  EF; Janssen  H; Walz  TM 《Blood》1996,87(9):3910-3918
Eosinophils are involved in the inflammatory response seen in allergy and helminthic infestations. Eosinophils synthesize transforming growth factor-alpha (TGF-alpha), which may play a role in the development of the characteristic fibrosis seen in longstanding high eosinophilia. Using immunoelectron microscopic techniques, eosinophils from peripheral blood of healthy individuals and from one patient with high eosinophilia showed presence TGF-alpha in matrix of the specific crystalloid-containing granules. In cryosections, TGF-alpha was also visualized in a vesicular compartment of the cytoplasm. In double- labeling experiments, the TGF-alpha of this latter compartment did not colocalize with CD63, a marker for lysosomes, nor with albumin of secretory vesicles. In extracts from eosinophils, obtained from healthy donors, immunoreactive TGF-alpha could be detected by enzyme-linked immunosorbent assay-technique. In addition, sera from two patients with high eosinophilia showed TGF-alpha concentrations of 1.5 ng/mL and 164 pg/mL, respectively, whereas TGF-alpha could not be detected in serum from healthy controls. In conclusion, TGF-alpha is present in the specific granules, and in an additional vesicular compartment of the cytoplasm of eosinophils.  相似文献   
97.
Pettengell  R; Testa  NG; Swindell  R; Crowther  D; Dexter  TM 《Blood》1993,82(7):2239-2248
Primitive hematopoietic cells released into the peripheral blood (PB) were studied in 50 patients with high-grade non-Hodgkin's lymphoma enrolled in a phase III trial of intensive weekly chemotherapy (VAPEC- B) alone or with granulocyte colony-stimulating factor (G-CSF). Mononuclear cells numbers were monitored and their in vitro growth potential assessed in clonogenic progenitor cell assays and in long- term culture. Total colony-forming cells (granulocyte-macrophage [GM], burst-forming unit, erythroid [BFU-E], Mix-CFC) were increased 40-fold (median) over baseline with chemotherapy alone and 106-fold with chemotherapy and G-CSF after the final dose. CD34+ cells were increased to a median of 4%, equivalent to that in normal bone marrow (BM) controls. Circulating colony-forming cell levels were maximal when the recovering total white blood cell (WBC) count reached 5 to 10 x 10(9)/L. The timing of the maximum was reproducible in individual patients. Therefore the WBC count can be used as a guide to the timing of leukapheresis. PB cells from normal controls' and patients' prechemotherapy were unable to sustain hemopoiesis in two-stage long- term cultures. In contrast, PB cells collected from patients primed with chemotherapy alone or chemotherapy with G-CSF at the time of predicted maximal colony-forming cell release were able to generate and sustain hematopoiesis in long-term cultures at a level comparable or superior to normal BM. These findings indicate that the use of G-CSF after routine outpatient chemotherapy stimulates maximal release of primitive hemopoietic cells into the circulation, including colony- forming cells and long-term culture-initiating cells. Their numbers are comparable with those in normal BM and are such that a single leukapheresis will usually yield enough cells for hemopoietic reconstitution after myeloablative chemotherapy.  相似文献   
98.
Presented is a review of thoracentesis, a procedure with which the emergency physician should be familiar. The pathophysiology of pleural effusions is described and is followed by a review of the clinical presentation and diagnosis. Special attention is given to technique and interpretation of results.  相似文献   
99.
100.
L-5-hydroxytryptophan (L-5-HTP)-induced myoclonus was used as a behavioral index of central serotonergic activity. Estradiol benzoate (EB) and progesterone (P) influenced the induction of myoclonus by L-5-HTP. When L-5-HTP was injected 46 h after EB, myoclonus was enhanced. P blocked this effect on EB when 100 or 125 mg/kg L-5-HTP (but not 80 mg/kg) was given 6 h after P in EB-primed animals. When L-5-HTP was given 3 or 11-15 h after P in EB-primed animals, there was no inhibitory effect of P on myoclonus. In fact, at the lowest dose (80 mg/kg), L-5-HTP increased myoclonus when given 3 h after P in EB-primed animals. The inhibitory effects of P in EB-primed females on myoclonus were temporally correlated with the display of lordosis, suggesting that the neural progestin receptor mechanisms that have been proposed to mediate P effects on lordosis are also involved in the inhibitory effects of P on myoclonus.  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