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   429篇
  免费   18篇
  国内免费   7篇
儿科学   55篇
妇产科学   4篇
基础医学   29篇
口腔科学   8篇
临床医学   24篇
内科学   98篇
皮肤病学   5篇
神经病学   15篇
特种医学   152篇
外科学   21篇
综合类   6篇
预防医学   7篇
眼科学   3篇
药学   15篇
肿瘤学   12篇
  2023年   1篇
  2021年   3篇
  2020年   2篇
  2019年   1篇
  2018年   4篇
  2017年   1篇
  2015年   4篇
  2014年   2篇
  2013年   6篇
  2012年   2篇
  2011年   4篇
  2010年   15篇
  2009年   9篇
  2008年   5篇
  2007年   10篇
  2006年   10篇
  2005年   3篇
  2004年   5篇
  2003年   3篇
  2002年   4篇
  2001年   6篇
  2000年   2篇
  1999年   8篇
  1998年   31篇
  1997年   24篇
  1996年   27篇
  1995年   26篇
  1994年   16篇
  1993年   19篇
  1992年   3篇
  1991年   5篇
  1990年   8篇
  1989年   15篇
  1988年   17篇
  1987年   13篇
  1986年   12篇
  1985年   20篇
  1984年   12篇
  1983年   13篇
  1982年   22篇
  1981年   9篇
  1980年   14篇
  1979年   1篇
  1978年   5篇
  1977年   12篇
  1976年   12篇
  1975年   5篇
  1974年   1篇
  1970年   1篇
  1968年   1篇
排序方式: 共有454条查询结果,搜索用时 0 毫秒
51.
Chang  JJ; Scott  CF; Colman  RW 《Blood》1986,67(3):805-810
High molecular weight (HMW) kininogen, the cofactor for activation of the contact system of plasma proteolysis, transports and optimally positions prekallikrein and factor XI on a negatively charged surface, allowing those zymogens to be activated by surface-bound factor XIIa. HMW kininogen circulates in plasma as a procofactor that, after cleavage by kallikrein or factor XIIa, gains ability to bind to the surface. The mechanism responsible for this increased affinity for the surface is unknown. We hypothesized that modification of arginine residues may prevent cleavage of HMW kininogen, since the initial kallikrein-induced cleavage sites on the HMW kininogen molecule are at the NH2 terminal and the COOH terminal of the bradykinin-containing portion of the molecule, each of which contains arginine. We found that modification with butanedione of four arginine residues in the HMW kininogen molecule prevented bradykinin release, which results from cleavage of HMW kininogen. Furthermore, HMW kininogen coagulant activity was lost, in proportion to the degree of arginine modification, until 6.6 residues had been modified. Complex formation with prekallikrein, however, was found to be uneffected by the modification of modified HMW kininogen. To account for the loss of coagulant activity, we also examined the ability of modified HMWKa (active cofactor) to bind to an activating surface. The affinity of modified HMWKa for kaolin was tenfold less than the affinity of unmodified HMWKa. These data suggest that arginine residues play a critical role in the ability of HMW kininogen to function as an activation cofactor, both by preventing the cleavages that produce HMWKa as well as by decreasing the affinity of HMWKa for the surface.  相似文献   
52.
Smith  WS; Sumnicht  GE; Sharpe  RW; Samuelson  D; Millard  FE 《Blood》1995,86(4):1301-1309
Sepsis is a common cause of morbidity and mortality. Neutrophils are the major defense against bacterial invasion, and granulocyte colony- stimulating factor (G-CSF) augments both neutrophil number and function. In our study, 160 rabbits were inoculated transtracheally with 0.5 mL of a solution containing 10(4) colony forming units per milliliter of Pasteurella multocida. Twenty-four hours later, chest x- rays and quantitative blood cultures demonstrated pneumonia and bacteremia. Therapy was then begun with penicillin G and either recombinant human G-CSF (rG-CSF; 5 to 8 micrograms/kg subcutaneously) or placebo every day for 5 days. Arterial blood gases and 23 other parameters of organ function were performed before inoculation and serially thereafter. All rabbits underwent histologic examination of organs at the time of septic death or when sacrificed on day 6. A total of 149 rabbits survived long enough to initiate therapy. A significant increase in leukocytes by day 4 was found in the rG-CSF-treated group. There was a trend towards improved survival in the rG-CSF group (77% v 67%; P = .13, n = 149). Analysis of pretreatment variables revealed sepsis-induced leukopenia (< or = 2,800/microL) as the only predictor of significantly improved survival with rG-CSF treatment (57% v 39%; P = .04, n = 73). The majority of the survival benefit occurred within the first 24 hours of treatment. This was before the time that a significant difference in mean white blood cell (WBC) count was observed between the study groups, making intravascular leukocytosis an unlikely explanation for the survival advantage in the rG-CSF group. No significant difference in laboratory variables reflecting organ function was demonstrated between the groups. Histologic grading of inflammation (0, normal, to 6, necrosis) in seven organs revealed that the surviving rabbits had mild but statistically significant increased inflammation in the liver, spleen, and noninoculated lung in the rG-CSF versus placebo groups (liver: 2.6 v 1.5, P < or = .0001; spleen: 3.2 v 2.3, P < or = .0001; and noninoculated lung: 2.9 v 2.5, P = .04). Administration of rG-CSF, in addition to penicillin G, in immune competent rabbits with gram-negative sepsis complicated by leukopenia significantly improved survival over antibiotics alone. The administration of rG-CSF in early sepsis for a short therapeutic duration was not associated with any clinically evident toxicity. Clinical trials using rG-CSF in septic patients with leukopenia are indicated.  相似文献   
53.
54.
ACTION OF CHOLINESTERS ON SENSORY NERVE ENDINGS IN SKIN AND MUSCLE   总被引:1,自引:0,他引:1  
1. This is a review of the literature on the subject of the effects of cholinesters and their agonists on sensory nerve endings. 2. The present-day view is that acetylcholine (ACh) has an excitatory action on some cutaneous receptors. Responses appear to be limited to receptors served by small myelinated and un-myelinated axons where responsiveness is multimodal; that is, the receptors are activated by noxious thermal and mechanical stimulation. 3. The possible role played by acetylcholine in sensory transduction processes is discussed, as are other explanations for the presence of nicotinic cholinergic receptors on the terminals of cutaneous receptors. 4. The excitatory action of ACh and succinylcholine (SCh) on muscle spindles is described. Two possible mechanisms are considered: a direct depolarizing action on the nerve terminals and indirect excitation, brought about by a contracture of the intrafusal fibres on which the sensory endings lie. 5. The technique of using SCh in combination with fusimotor stimulation is described. This has provided new information about the internal workings of muscle spindles. Brief mention is also made of the action of SCh on tendon organs and joint receptors. 6. It is concluded that a direct action by cholinesters is restricted to receptors served by small axons with multimodal functions. The precise role of such an action remains the subject of speculation. Possible clinical significance is discussed.  相似文献   
55.
56.
57.
Non-insulin-dependent diabetes mellitus (NIDDM) occurs with a higher frequency in Hispanic as compared with non-Hispanic whites. It also appears that there is a higher prevalence of diabetic nephropathy in the Hispanic population when compared with non-Hispanic whites. In the current study, 144 Hispanics and 671 non-Hispanic white NIDDM subjects were studied to determine the possible association of various risk factors and diabetic complications, including overt albuminuria, with diabetic retinopathy. Stereoscopic retinal fundus photographs were obtained and graded by the University of Wisconsin Fundus Photographic Reading Center. We also sought to determine whether risk factors for retinopathy vary between Hispanics and non-Hispanic whites. In the total group, duration of diabetes, glycosylated hemoglobin, neuropathy, diastolic hypertension, use of insulin, and Hispanic ethnicity correlated with the presence of retinopathy. Controlling for severity and duration of diabetes, Hispanics had a significantly increased risk of retinopathy relative to non-Hispanic whites (OR = 2.13, 95% CI = 1.34, 3.37, P = 0.0013). Duration of diabetes and presence of neuropathy were significantly correlated with the presence of diabetic retinopathy in Hispanics and non-Hispanic whites. The presence of overt albuminuria (>200 microg/min), although not related to diabetic retinopathy in non-Hispanic whites, conferred a high risk for diabetic retinopathy in Hispanics (OR = 11.14, CI = 1.20, 103.39, P = 0.0339) independent of other risk factors. In summary, Hispanics with NIDDM have an increased prevalence of diabetic retinopathy when compared with non-Hispanic whites. In addition, overt albuminuria in the Hispanic subjects appears to be a powerful predictor of the diabetic retinopathy.  相似文献   
58.
59.
SUMMARY Carbamazepine is regularly used in the treatment of trigeminal neuralgia. Although exacerbation of psychosis has been described following abrupt discontinuation of carbamazepine in chronic schizophrenics, a withdrawal syndrome has not been reported previously in patients treated for trigeminal neuralgia. The case presented here suggests that abrupt withdrawal of toxic concentrations of carbamazepine may precipitate a withdrawal reaction, which is manifest some days after discontinuation of the drug. Therefore it may be advisable to withdraw therapy slowly in these situations.  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