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   1447篇
  免费   74篇
  国内免费   35篇
耳鼻咽喉   9篇
儿科学   74篇
妇产科学   11篇
基础医学   205篇
口腔科学   48篇
临床医学   179篇
内科学   286篇
皮肤病学   29篇
神经病学   66篇
特种医学   195篇
外科学   174篇
综合类   33篇
预防医学   56篇
眼科学   20篇
药学   90篇
中国医学   1篇
肿瘤学   80篇
  2023年   10篇
  2022年   14篇
  2021年   30篇
  2019年   19篇
  2018年   30篇
  2017年   18篇
  2016年   16篇
  2015年   26篇
  2014年   19篇
  2013年   47篇
  2012年   46篇
  2011年   42篇
  2010年   64篇
  2009年   55篇
  2008年   39篇
  2007年   48篇
  2006年   57篇
  2005年   57篇
  2004年   30篇
  2003年   30篇
  2002年   22篇
  2001年   30篇
  2000年   36篇
  1999年   46篇
  1998年   63篇
  1997年   50篇
  1996年   53篇
  1995年   38篇
  1994年   43篇
  1993年   36篇
  1992年   21篇
  1991年   29篇
  1990年   18篇
  1989年   36篇
  1988年   58篇
  1987年   27篇
  1986年   24篇
  1985年   48篇
  1984年   17篇
  1983年   12篇
  1982年   11篇
  1981年   11篇
  1980年   15篇
  1979年   15篇
  1978年   11篇
  1977年   10篇
  1976年   13篇
  1975年   9篇
  1974年   7篇
  1972年   8篇
排序方式: 共有1556条查询结果,搜索用时 15 毫秒
51.
该文旨在介绍Beth Israel医疗中心采用大剂量术中放疗(HDR-IORT)治疗复发头颈癌的经验。对2001-2010年间头颈癌局部复发接受大剂量HDR-IORT的患者进行回顾分析。结果,76例患者的87个部位在肿瘤切除后接受了治疗。术后2年控制率为62%。平均总生存期为19个月,其中42%的患  相似文献   
52.
53.
OBJECTIVE: To examine how parental responses following pediatric injury may influence their child's posttraumatic stress symptoms (PTSS). METHODS: Heart rate (HR) from 82 pediatric injury patients was measured during emergency medical services (EMSs) transport and following hospital admission. Twelve-hour urinary cortisol levels were assessed upon admission. Child PTSS and parental PTSS and general distress were assessed 6 weeks and 6 months after trauma. RESULTS: Six-week parental PTSS predicted 6-month child PTSS even after controlling for demographics and general parent distress (DeltaR(2) = .08, p = .03). Parental PTSS moderated the relationship between (a) child cortisol levels and 6-month child PTSS (DeltaR2 = .08, p = .03) and between (b) hospital HR and 6-month child PTSS (DeltaR2 = .09, p = .03). CONCLUSION: The present findings suggest that parental response to trauma may interact with child acute physiological responses to predict persistent child PTSS.  相似文献   
54.
55.
Cortical bone porosity is intimately linked with remodeling, is of growing clinical interest, and is increasingly accessible by imaging. Thus, the potential of animal models of osteoporosis (OP) to provide a platform for studying how porosity develops and responds to interventions is tremendous. To date, rabbit models of OP have largely focused on trabecular microarchitecture or bone density; some such as ovariectomy (OVX) have uncertain efficacy and cortical porosity has not been extensively reported. Our primary objective was to characterize tibial cortical porosity in rabbit-based models of OP, including OVX, glucocorticoids (GC), and OVX + GC relative to controls (SHAM). We sought to: (i) test the hypothesis that intracortical remodeling is elevated in these models; (ii) contrast cortical remodeling and porosity in these models with that induced by parathyroid hormone (1–34; PTH); and (iii) contrast trabecular morphology in the proximal tibia across all groups. Evidence that an increase in cortical porosity occurred in all groups was observed, although this was the least robust for GC. Histomorphometric measures supported the hypothesis that remodeling rate was elevated in all groups and also revealed evidence of uncoupling of bone resorption and formation in the GC and OVX + GC groups. For trabecular bone, a pattern of loss was observed for OVX, GC, and OVX + GC groups, whereas the opposite was observed for PTH. Change in trabecular number best explained these patterns. Taken together, the findings indicated rabbit models provide a viable and varied platform for the study of OP and associated changes in cortical remodeling and porosity. Intriguingly, the evidence revealed differing effects on the cortical and trabecular envelopes for the PTH model. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR)..  相似文献   
56.
57.
Plasma membrane receptors that couple to guanine nucleotide-binding regulatory proteins (G proteins) undergo a variety of rapid (minutes) and longer term (hours) regulatory processes induced by ligands. For the beta 2-adrenergic receptor (beta 2AR), the rapid processes include functional desensitization, mediated by phosphorylation of the receptor by the cAMP-dependent protein kinase and the beta-adrenergic receptor kinase, as well as a loss of hydrophilic ligand binding proposed to represent sequestration of receptors into a cellular compartment distinct from the plasma membrane. The slower processes include beta 2AR down-regulation (i.e., a decrease in the total cellular complement of receptors). It is not yet known whether beta 2AR phosphorylation and/or sequestration are prerequisites for down-regulation of the receptor. Like other G protein-coupled receptors, the beta 2AR molecule spans the plasma membrane seven times, and the cytoplasmic carboxyl-terminal domain has been proposed to contain molecular determinants for each of these regulatory processes. We replaced four serine and threonine residues located within a 10-amino acid segment of this domain of beta 2AR and thereby prevented agonist-promoted phosphorylation, sequestration, and rapid desensitization of the adenylyl cyclase response. In contrast, these mutations did not affect functional coupling to the stimulatory G protein Gs or long-term down-regulation. These findings thus define a small, hitherto unappreciated region of the receptor molecule that may selectively subserve its rapid regulation. In addition, with the demonstration that beta 2AR does not have to be phosphorylated or sequestered in order to enter the down-regulation pathway, the results suggest that the classical receptor endocytosis model may not be appropriate for beta 2AR regulation.  相似文献   
58.
Relatively nonmyelotoxic drugs and drug combinations were investigated for their ability to eliminate malignant cells from human bone marrow. In vitro 90% inhibitory concentration (IC90) doses were established on granulocyte macrophage colony-forming units (GM-CFU) in culture of bone marrow by using the GM-CFU assay for the following drugs: 4- hydroperoxycyclophosphamide (4-HC), Adriamycin, L-asparaginase, bleomycin, hydrocortisone, VP-16, spirogermanium, Taxol, and vincristine. The leukemic cell kill efficiency of these drugs at IC90 doses was compared with that of 4-HC on acute lymphoid leukemia (ALL) cell lines by using the limiting-dilution assay. Under these conditions, no single drug was superior to 4-HC. To increase the in vitro effect in leukemic cell kill, combinations of vincristine with hydrocortisone, Adriamycin, VP-16, and 4-HC were investigated. Vincristine at 1 to 5 micrograms/mL increased the marrow cytotoxicity of hydrocortisone, Adriamycin, and VP-16, but it was protective (subadditive) with 4-HC. Vincristine and 4-HC in combination was additive to supraadditive on ALL cell lines, increased the leukemic cell kill by one to two logs above 4-HC alone at IC90 doses (P less than .05), and was not affected by the addition of excess marrow cells. The recommended doses for chemopurging in clinical studies are vincristine, 1 to 5 micrograms/mL, plus 4-HC, 5 micrograms/mL.  相似文献   
59.
Major surgery is associated with substantial morbidity and mortality with early post-operative adverse events (POAE) occurring in 30% of patients within the first 30 days. The underlying pathogenesis is multifactorial, including immune dysfunction and increased inflammatory response to surgery. We investigated preoperative immune function by the TruCulture® whole blood technique in a cohort of patients undergoing pancreaticoduodenectomy (PD), hypothesizing that patients developing inflammatory POAE defined as leucocytosis, fever or high (above median) area under the curve (AUC) C-reactive protein (CRP) the first post-operative week would display perturbed preoperative immune function. Sixty-two adult patients were screened, 30 included and 11 excluded post-inclusion due to other surgical procedures than PD and post-operative complications directly attributed to surgery, leaving 19 patients for analysis of preoperative immune function. Patients developing leucocytosis (n = 5, 26%) had lower Toll-like receptor (TLR)-3–stimulated IL-12p40 and higher Candida Albicans (TLR1/2/4/6, Dectin-1)-stimulated TNF-α, compared to patients without leucocytosis (all P < .05). Patients developing fever (n = 7, 37%) had lower TLR7/8-stimulated IFN-γ and patients with high AUC CRP (n = 9, 47%) had lower TLR3-stimulated IFN-γ and IL-6 and lower TLR7/8-stimulated IL-10 (all P < .05), compared to patients without fever or low CRP, respectively. In conclusion, patients with inflammatory POAE displayed lower preoperative stimulated IL-12p40, IFN-γ, IL-6 and IL-10 and higher TNF-α response, compared to patients without inflammatory POAE. This finding suggests that TruCulture is a feasible immunologic screening tool in surgical patients, with a potential for preoperative identification of patients at increased risk for inflammatory POAE, allowing for risk-based intervention trials.  相似文献   
60.
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