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   892篇
  免费   95篇
  国内免费   14篇
耳鼻咽喉   3篇
儿科学   27篇
妇产科学   31篇
基础医学   76篇
口腔科学   5篇
临床医学   64篇
内科学   182篇
皮肤病学   35篇
神经病学   52篇
特种医学   169篇
外科学   145篇
综合类   23篇
预防医学   93篇
眼科学   50篇
药学   19篇
中国医学   1篇
肿瘤学   26篇
  2021年   10篇
  2019年   14篇
  2018年   17篇
  2017年   14篇
  2016年   19篇
  2015年   9篇
  2014年   18篇
  2013年   21篇
  2012年   36篇
  2011年   29篇
  2010年   21篇
  2009年   29篇
  2008年   25篇
  2007年   39篇
  2006年   24篇
  2005年   20篇
  2004年   22篇
  2003年   14篇
  2002年   13篇
  2001年   14篇
  2000年   12篇
  1999年   14篇
  1998年   19篇
  1997年   29篇
  1996年   28篇
  1995年   20篇
  1994年   17篇
  1993年   17篇
  1992年   14篇
  1991年   11篇
  1989年   26篇
  1988年   25篇
  1987年   25篇
  1986年   24篇
  1985年   24篇
  1984年   19篇
  1983年   12篇
  1979年   14篇
  1978年   13篇
  1977年   8篇
  1976年   12篇
  1975年   13篇
  1974年   8篇
  1973年   16篇
  1972年   11篇
  1971年   11篇
  1970年   8篇
  1969年   8篇
  1967年   8篇
  1966年   11篇
排序方式: 共有1001条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
25.
Incident pain related to bone metastases is a problematic symptom to treat. The difficulty in treating this type of pain is reflected in the wide variety of treatment modalities recommended. The aims of this prospective observational study were to determine the patterns of pain severity at rest and on movement over time and which treatment modalities are employed. In addition, we were interested in ascertaining any correlations between bone pain at rest, bone pain on movement and functional ability. Thirty-two patients were followed up for a mean of 22 weeks (range: 2-52). In total, there were 704 patient follow-up weeks. Patients were followed up for one year or until death. A total of 19 different treatment modalities were employed. There were strong correlations between pain at rest and pain on movement. There were no significant correlations between functional ability and pain at rest or movement. Our study demonstrates the complex management of patients with bone pain. This is the first study that highlights the correlation between pain at rest and pain on movement in patients with bone metastases in a palliative care population. It highlights the need for intensive follow-up of these patients, as they require multiple interventions to help control their pain. These data can also be used to power further interventional studies.  相似文献   
26.
27.
Sporn  LA; Marder  VJ; Wagner  DD 《Blood》1987,69(5):1531-1534
Large multimers of von Willebrand factor (vWf) are released from the Weibel-Palade bodies of cultured endothelial cells following treatment with a secretagogue (Sporn et al, Cell 46:185, 1986). These multimers were shown by immunofluorescent staining to bind more extensively to the extracellular matrix of human foreskin fibroblasts than constitutively secreted vWf, which is composed predominantly of dimeric molecules. Increased binding of A23187-released vWf was not due to another component present in the releasate, since releasate from which vWf was adsorbed, when added together with constitutively secreted vWf, did not promote binding. When iodinated plasma vWf was overlaid onto the fibroblasts, the large forms bound preferentially to the matrix. These results indicated that the enhanced binding of the vWf released from the Weibel-Palade bodies was likely due to its large multimeric size. It appears that multivalency is an important component of vWf interaction with the extracellular matrix, just as has been shown for vWf interaction with platelets. The pool of vWf contained within the Weibel-Palade bodies, therefore, is not only especially suited for platelet binding, but also for interaction with the extracellular matrix.  相似文献   
28.
P U Heitz  M Kasper  S van Noorden  J M Polak  H Gregory    A G Pearse 《Gut》1978,19(5):408-413
Urogastrone has been localised by immunostaining to granules of the cells of human duodenal (Brunner's) glands and their ducts and of acinar cells in the human submandibular gland. The immunoreactive peptide is present in large quantities in duodenal glands and their secretory ducts. Urogastrone or human epidermal growth factor promotes cellular proliferation in vivo as well as in vitro and inhibits gastric acid secretion and may, therefore, be one of the duodenal factors inhibiting gastric activity. Thus it may have an important regulatory and protective function for the intestinal mucosa and may possibly become a useful therapeutic agent.  相似文献   
29.
Endotoxin is a component of gram-negative bacteria that causes hematologic and immunologic changes through its induction of cytokines. Interleukin-1 receptor antagonist (IL-1Ra) is a naturally occurring inhibitor of IL-1 that competes with IL-1 for occupancy of cell-surface receptors but possesses no agonist activity. We investigated the ability of human recombinant IL-1Ra to block the effects of low-dose endotoxin. Fourteen healthy male volunteers between 18 and 30 years old were injected intravenously with 3 ng/kg Escherichia coli endotoxin. Concurrent with the injections, nine volunteers received a 3-hour continuous intravenous infusion of IL-1Ra. The other five subjects were given a 3-hour infusion of saline. Volunteers injected with endotoxin experienced a threefold increase in circulating neutrophils over baseline. This neutrophilia was significantly reduced by 48% in subjects administered endotoxin plus IL-1Ra (P = .0253). Ex vivo mitogen-induced peripheral blood mononuclear cell proliferation decreased by greater than 60% at 3 and 6 hours after endotoxin injection (P = .0053). This endotoxin-induced reduction in mitogen response was reversed in subjects coinjected with IL-1Ra (P = .0253). Endotoxin-induced symptoms, fever, and tachycardia were unaffected by IL-1Ra. IL-1 appears to be an important mediator in endotoxemia because some of its hematologic and immunomodulatory effects can be blocked by IL-1Ra.  相似文献   
30.
Marquette  KA; Pittman  DD; Kaufman  RJ 《Blood》1995,86(8):3026-3034
Blood coagulation factors V and VIII are homologous proteins that have the domain organization A1-A2-B-A3-C1-C2. Upon thrombin activation, the B-domains of both molecules are released. Previous studies on factor VIII showed that the B-domain was not required for thrombin cleavage or activity. In contrast, deletion of the factor V B-domain (residues 709 to 1545) yielded a molecule with sevenfold reduced procoagulant activity that was not cleaved by thrombin. However, this factor V B- domain deletion molecule was activated by factor Xa, although the fold- activation was 85% that of wild-type factor V. Thrombin cleavage of factor V occurs initially after residue 709 and subsequently after residues 1018 and 1545. The requirement for thrombin cleavage within the B-domain at residue 1018 was evaluated by mutagenesis of Arg1018 to Ile. In the resultant R1018I mutant, the rate of thrombin activation and appearance of maximal cofactor activity was delayed and was consistent with delayed cleavage of the light chain at residue 1545. In contrast, the rate of factor Xa activation in the R1018I mutant was not altered. This finding suggests that thrombin cleavage at 1018 facilitates subsequent thrombin cleavage at 1545. Further mutagenesis was used to study the requirement for sequences within the factor V B- domain for thrombin cleavage at residue 1545. Whereas the factor V deletion molecule removing residues 709 to 1545 was not cleaved by thrombin, a smaller B-domain deletion molecule (residues 709 to 1476) containing an acidic amino acid-rich region (residues 1490 to 1520) was effectively cleaved by thrombin. These results show that residues 1476 to 1545, which contain an acidic amino acid-rich region, were required for thrombin cleavage of the light chain. Introduction of an acidic amino acid-rich region from factor VIII (residues 337 to 372) into the factor V 709 to 1545 deletion also restored thrombin cleavage of the light chain. In contrast, similar replacement with the acidic region from the factor VIII light chain (residues 1649 to 1689) was significantly less effective in promoting thrombin cleavage of the light chain. This finding suggests that the different acidic regions in factors V and VIII are not functionally equivalent in their interaction with thrombin.(ABSTRACT TRUNCATED AT 400 WORDS)  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