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   1046篇
  免费   77篇
  国内免费   47篇
耳鼻咽喉   1篇
儿科学   20篇
妇产科学   5篇
基础医学   56篇
口腔科学   52篇
临床医学   56篇
内科学   167篇
皮肤病学   32篇
神经病学   19篇
特种医学   22篇
外科学   47篇
综合类   138篇
预防医学   107篇
眼科学   13篇
药学   347篇
  1篇
中国医学   32篇
肿瘤学   55篇
  2023年   13篇
  2022年   13篇
  2021年   42篇
  2020年   27篇
  2019年   25篇
  2018年   16篇
  2017年   27篇
  2016年   31篇
  2015年   36篇
  2014年   45篇
  2013年   70篇
  2012年   48篇
  2011年   56篇
  2010年   35篇
  2009年   46篇
  2008年   50篇
  2007年   59篇
  2006年   55篇
  2005年   39篇
  2004年   53篇
  2003年   27篇
  2002年   33篇
  2001年   24篇
  2000年   21篇
  1999年   23篇
  1998年   24篇
  1997年   34篇
  1996年   17篇
  1995年   19篇
  1994年   21篇
  1993年   14篇
  1992年   12篇
  1991年   16篇
  1990年   13篇
  1989年   8篇
  1988年   9篇
  1987年   7篇
  1986年   13篇
  1985年   11篇
  1984年   4篇
  1983年   7篇
  1982年   10篇
  1981年   3篇
  1980年   5篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有1170条查询结果,搜索用时 31 毫秒
991.
The relation between the duration of ischemic ST-segment depression (1 mm or more 60 ms after the J point) and the clinical awareness of chest pain was studied in 31 patients (aged 39-73 years) undergoing symptom-limited, graded treadmill exercise testing. The response of these patients to nitrate therapy (spray or sublingual tablet) given immediately on cessation of exercise was also studied. During exercise, angina pectoris appeared at an estimated workload of 4.6 +/- 2.2 metabolic equivalents (METS) (mean +/- SD), and pathological ST-segment depression at 4.9 +/- 1.9 METS (p = NS.) On cessation of exercise, angina disappeared after 3.0 +/- 1.9 min, but ST-segment depression persisted for more than twice as long (6.6 +/- 4.1 min) (p less than 0.0001). The ratio of time to ST-segment recovery/time to relief of pain (a quantitative measure of silent ischemia during recovery) increased with age (r = 0.49, p = 0.002), and in 16 patients over 60 years of age was higher than in 15 younger patients (3.6 +/- 2.5 vs. 2.1 +/- 1.4) (p less than 0.04). The silent ischemia ratio after exercise tended to decrease, although not significantly so (p = 0.2), in patients who received oral nitrates; there was no difference in the response to spray or tablet in this regard. We conclude that ST-segment depression frequently persists after relief of exercise-induced angina pectoris and more so in elderly patients.  相似文献   
992.
The purpose of this study was to evaluate the efficacy of sublingual nitroglycerin (NTG) during treatment with oral sustained-release isosorbide dinitrate (ISDN) in two doses: 80 mg and 120 mg. In a double-blind crossover design study 38 men with stable angina initially received either an oral placebo (OP) or ISDN. All patients received either NTG 0.5 mg or sublingual placebo (SLP) 2.5 h after OP ingestion, but only NTG 2.5 h after ISDN. The same pattern was used in the first ingestion and in long-term OP or ISDN therapy for 7 days (OP and ISDN every 6 h, and ISDN once daily). The efficacy of NTG was evaluated by analyzing walking time to ischaemia (WTI) during exercise tests performed 5 minutes after NTG or SLP administration, and the efficacy of ISDN 2 h and 6 h after oral ingestion. In the first ingestion NTG significantly improved WTI (p < 0.0001) by 42.7% after OP, by 46.5% after 80 mg ISDN and by 52.1% after 120 mg. After long-term OP therapy NTG prolonged WTI (p < 0.01) by 15.6%, during once-daily ISDN treatment, an 80 mg dose prolonged WTI by 22.8% and a dose of 120 mg by 36.5%. However, NTG did not improve WTI in q.i.d. therapy. Six hours after the first 80 mg ISDN ingestion WTI improved (p < 0.0001) by 66.0%, and after 120 mg by 58.4%. Following once-daily therapy ISDN prolonged WTI (p < 0.0001) by 27.2% after an 80 mg dose and by 36.2% after a dose of 120 mg. No improvement was observed in q.i.d. treatment. Thus, severe tolerance to ISDN abolishes the anti-ischaemic effects of NTG, and appropriate regimens of ISDN have considerable anti-anginal effects during chronic administration.  相似文献   
993.
BACKGROUND: The role of nitric oxide synthase (NOS) in autoimmune disease is gaining increased attention because of the relationships between NOS activity and T-lymphocyte subpopulations and, in particular, the influence of NO on cytokine production by Th1 versus Th2 cells. In addition, there is evidence that both the liver and infiltrating hepatic T cells have inducible NOS-2 activity. METHODS: We studied serum levels of nitrite (NO2-) and nitrate (NO3-) in groups of patients with liver disease secondary to hepatitis B, hepatitis C, autoimmune hepatitis and primary biliary cirrhosis (PBC). Simultaneously, in a nested subpopulation, we studied the liver expression of NOS-2. RESULTS: Interestingly, there was a significant elevation both of nitrite and of nitrate in patients with PBC but not other liver diseases. Despite such increments, there was no correlation of the levels of nitrite and nitrate with sera levels of tumor necrosis factor-alpha, interferon-gamma, alanine aminotransferase, total bilirubin, alkaline phosphatase, gamma-glutamyl transpeptidase, platelet count, IgG, IgM, antimitochondrial antibodies or prothrombin time. These data were extended by demonstrating the expression of NOS-2 by immunohistochemistry in 13/14 patients with PBC, including in 9/14 patient hepatocyte populations and 4/14 bile duct cells. In contrast, NOS-2 expression was noted in hepatitis B and hepatitis C, but only found within mononuclear cells. CONCLUSION: Our data suggest that NO produced through NOS-2 may play a role in the pathogenesis of bile duct injury in some PBC patients.  相似文献   
994.
995.
CharactericsofupperdigestivetractdiseasesinfishermenoftheBohaiBayWANGYuanBen1,WANGYuanPing1,ZOUJing1,BAIBaoJie2,RENGuoChu...  相似文献   
996.
Abstract

Because of its potential as a low cost first-line monotherapy for the most common vulvovaginal infections, we evaluated fenticonazole nitrate in a prospective, open-label, multicenter pilot study with 101 sexually active women (per-protocol; 16 to 61 years of age) with vulvovaginitis involving single or mixed infections with Candida albicans, Trichomonas vaginalis, and/or Gardnerella vaginalis. Fenticonazole nitrate (1 g) was administered as vaginal ovules, once daily on days 1 and 3. Eradication (direct phase-contrast microscopy of vaginal swabs and/or microbiological culture) on day 8 was 90% (C. albicans, 26/29, p <0.001), 70% (T. vaginalis, 7/10, p = 0.161), 67% (G. vaginalis, 22/33, p <0.009), and 45% (mixed infection, 13/29, p = 0.001). After 28 days, relapse was 0% for candidiasis and trichomoniasis, 27% (6/22) for G. vaginalis, and 23% (3/13) for mixed infection. Overall, eradication of all offending pathogens was achieved in 67% of the total per-protocol population, with a relapse rate of only 16%. Score sums for symptoms improved from 7.0 (baseline) to 1.7 (day 8), and 0.71 (day 28), (p < 0.001). Treatment was safe and well tolerated.

The results of our pilot study suggest that application of fenticonazole nitrate 1 g intravaginal ovules on 2 alternate days is a suitable first-line treatment of vulvovaginitis with acceptable broad-spectrum efficacy against the most commonly involved pathogens and with a low rate of early relapse, reserving antibiotics for patients with treatment failure or relapse of infection. Our results should encourage further examination of this approach in larger and well controlled clinical trials.  相似文献   
997.
陈建勤 《护士进修杂志》2014,(20):1829-1829
皮硝外敷在临床上广泛应用于肝硬化、胰腺炎、腹膜炎等患者,将其外敷于腹部可以减轻腹胀、腹痛等不适症状。传统方法,用毛巾或治疗巾将皮硝包裹后外敷患者腹部,用胶布固定。缺点是皮硝不易固定、易移位、易外漏,皮硝遇热溶解变硬,易污染病服,也增加了对皮肤的刺激与摩擦。为此,我科于2013年3月,应用医用腹带进行改良制作了皮硝外敷袋,效果满意。现介绍如下。  相似文献   
998.
A 51-year-old man was admitted with distal metaphyseal tibial fracture after falling whilst intoxicated by alcohol. In the emergency department he was found to be hypoxic, with normal chest radiography. It transpired that he had also inhaled amyl nitrate (Poppers) and was diagnosed with methaemogloblinaemia. Initial concerns of fat embolus however led to delay to surgery and unnecessary CT pulmonary angiogram. His methaemogloblinaemia was appropriately managed and his tibial fracture was treated operatively without complication.We report this case to raise awareness of methaemogloblinaemia associated with the abuse of inhaled amyl nitrate when treating patients who have sustained injury whist intoxicated. Appropriate investigation can prevent delayed management of this unusual but potentially life-threatening drug reaction.  相似文献   
999.
Background: Nitrite and nitrate are exhaled in droplets of an aerosol during breathing and can be assayed in the exhaled breath condensate (EBC) as markers of nitrossative stress in the airways of patients with asthma, COPD, and idiopathic pulmonary fibrosis (IPF). Subjects and methods: Using HPLC with fluorescence detection, nitrite and nitrate were assayed in EBC of 14 atopic patients with mild‐to‐moderate stable asthma, 18 atopic asthmatics with exacerbation, 14 COPD patients without exacerbation, 18 patients with exacerbated COPD, 13 patients with active IPF, and in 29 healthy subjects. Results: The geometric mean [exp(mean±SD)] EBC concentrations of nitrite (micromol/l) in patients with asthma [5.1(2.1–12.3)], exacerbation of asthma [5.1(2.8–9.6)], exacerbation of COPD [5.3(3.2–8.7)], and with IPF [5.5(2.9–10.2)] were higher (P<0.05) compared with those of healthy subjects [2.9(1.6–5.3)] and patients with stable COPD [3.0(1.3–6.7)]. Nitrite concentration increased with decreased lung function of patients with asthma (rs=?0.31, P<0.02). Presumably owing to the contamination of the EBC sample with nitrate during collection, nitrate levels were highly variable among healthy subjects and higher compared with all groups of patients. Conclusion: EBC nitrite is a suitable marker of nitrossative stress in adult patients with lung diseases but cannot differentiate controlled and exacerbated asthma. Further improvements to the methods of EBC collection and sample handling are warranted. J. Clin. Lab. Anal. 24:317–322, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   
1000.
The main aim of this work was to develop a kinetic spectrophotometric method for the quantitative analysis of isoxsuprine hydrochloride in commercial tablets. The method is based on the reaction of isoxsuprine hydrochloride (ISx) with hydroxylamine hydrochloride and ammonium cerium (IV) nitrate in sulphuric acid medium at room temperature which resulted in the formation of yellow‐coloured product peaking at 380 nm. The reaction is followed spectrophotometrically by measuring the absorbance as a function of time. Fixed time method (ΔA = A4–A2, where A2 and A4 refer to absorbance measurements taken at 2 and 4 min, respectively) was adopted for constructing the calibration curve which was found to be linear over the concentration range of 30–80 µgmL?1 with molar absorptivity of 5.95 × 103 L mol?1 cm?1. The method has been applied successfully to the determination of isoxsuprine hydrochloride in tablets. Statistical comparison (point and interval hypothesis tests) of the results showed that there is no significant difference between the proposed method and reference method. Copyright © 2010 John Wiley & Sons, Ltd.  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