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   996篇
  免费   41篇
  国内免费   7篇
儿科学   66篇
妇产科学   10篇
基础医学   105篇
口腔科学   11篇
临床医学   80篇
内科学   250篇
皮肤病学   55篇
神经病学   73篇
特种医学   25篇
外科学   142篇
综合类   5篇
预防医学   44篇
眼科学   19篇
药学   63篇
中国医学   3篇
肿瘤学   93篇
  2023年   7篇
  2022年   9篇
  2021年   17篇
  2020年   4篇
  2019年   14篇
  2018年   20篇
  2017年   18篇
  2016年   18篇
  2015年   22篇
  2014年   38篇
  2013年   34篇
  2012年   49篇
  2011年   40篇
  2010年   33篇
  2009年   32篇
  2008年   32篇
  2007年   61篇
  2006年   65篇
  2005年   43篇
  2004年   38篇
  2003年   25篇
  2002年   37篇
  2001年   10篇
  2000年   5篇
  1999年   14篇
  1998年   36篇
  1997年   34篇
  1996年   28篇
  1995年   36篇
  1994年   29篇
  1993年   18篇
  1992年   8篇
  1991年   15篇
  1990年   12篇
  1989年   14篇
  1986年   7篇
  1985年   5篇
  1984年   5篇
  1983年   7篇
  1981年   8篇
  1980年   6篇
  1976年   4篇
  1975年   3篇
  1973年   3篇
  1959年   6篇
  1958年   12篇
  1957年   9篇
  1956年   18篇
  1955年   12篇
  1954年   5篇
排序方式: 共有1044条查询结果,搜索用时 15 毫秒
41.
OBJECTIVE: This study was performed to evaluate serum creatine kinase (CK) levels during tocolytic therapy. METHODS: A retrospective study was performed in 27 patients who were treated with intravenous tocolytic agents for more than one week. The first-line tocolytic agent was ritodrine hydrochloride, followed by concomitant magnesium sulfate (MgSO4). The serum CK level was measured on admission and every week thereafter. The patients were divided into the normal CK (group 1) and abnormal CK (> 150 IU/L) (group 2) groups. RESULTS: Seventeen patients received both ritodrine hydrochloride and MgSO4. The CK levels in all patients rose significantly from 58.4 +/- 30.8 IU/L on admission to 116.0 +/- 68.7 IU/L on day 7 (p = 0.002). Abnormal elevation of CK occurred in 7 (25.9%) of the 27 patients. Significant differences were found between groups 1 and 2 in the total doses of ritodrine and MgSO4 (p = 0.046 and p = 0.0028, respectively). All patients in group 2 received ritodrine in combination with MgSO4 (p = 0.018). CONCLUSION: When tocolytic therapy continued for more than 1 week, nearly one-fourth of patients showed an increase in CK level above the normal range.  相似文献   
42.
BACKGROUND: To understand what happens during the wound healing process of the mesothelium, we have developed an in vitro wounding model of cultured human peritoneal mesothelial cells (HPMCs) utilizing an image acquisition and analysis system. Using this system, cell mobility and hyaluronan synthesis were quantified and their interrelationship discussed. METHODS: 1N NaOH was used to create circular wounds in cultured HPMC monolayers, which were then exposed for 30 minutes to the peritoneal dialysis solutions or fetal calf serum (FCS)-free M199 culture medium, followed by incubation with 0.3% FCS/M199 culture medium for up to 96 hours. Digitalized microscopic date was captured every 30 minutes to quantify the wound healing process. In separate experiments, the HPMC monolayers were stained with biotin-conjugated hyaluronan-binding protein (B-HABP) at a regular time interval. RESULTS: Centripetal migration of the HPMCs into the wound area was the predominant process involved in wound repair with proliferation playing a secondary role. Two noticeable observations were made from the digital video movies: (1) cell mobility varied and was dependent upon the morphology and location of the cell relative to the wound edge, and (2) cell migration continued even after wound closure. Staining for B-HABP was confined to the remesothelialized area when wound closure was complete at 24 hours. At 48 hours after wound closure, the stained area was even more visible, although somewhat diffuse; thereafter, staining was reduced to almost background levels. CONCLUSION: The cell culture model of wound healing used in our study has enabled us to demonstrate quantitative image data of the cellular processes that occur during wound healing. We have been able to continuously observe cell migration, proliferation, and transformation. Synthesis and subsequent decomposition of hyaluronan appears to be related to the mobility of the wounded and intact HPMCs in this model system.  相似文献   
43.
BACKGROUND: Little is known about effect of ionic strength on local anesthetic toxicity. Using human erythrocytes, hemolytic action of dibucaine in solutions of various ionic strength was investigated. METHODS: The critical micellar concentration (CMC) of dibucaine and the dibucaine level that causes destruction of half of the red blood cells in vitro (EC50 value) were determined in solutions of various ionic strength. RESULTS: The mean CMC values of the dibucaine solutions adjusted to ionic strength 0.15, 0.30, 0.45 and 0.90 with NaCl, were 35.3, 22.6, 15.9 and 9.6 mM, respectively. The mean EC50 values of these solutions measured at 5 sec were 22.5, 16.0, 12.6 and 8.2 mM, respectively, and those at 30 min were 4.9, 4.5, 4.5 and 2.6 mM, respectively. There was a significant correlation between mean CMC values and mean EC50 values at 5 sec but not at 30 min in the solution of the same ionic strength. CONCLUSIONS: These findings indicated that the mechanism of dibucaine-induced hemolysis within a few seconds is through membrane lysis, whereas dibucaine-induced hemolysis at 30 min is caused by another mechanism. Because each mechanism is enhanced by high ionic strength, dibucaine dissolved in salt solution should not be administered intrathecally.  相似文献   
44.
Abstract. Sakano, T., Kittaka, E., Tanaka, Y., Yamaoka, H., Kobayashi, Y. and Usui, T. (Department of Paediatrics, Hiroshima University Hospital and Hiroshima City Hospital, Hiroshima, Japan). Vaccine-associated poliomyelitis in an infant with agammagiobulinemia. Acta Paediatr Scand, 69:549, 1980.—We describe a female infant with agammaglobulinemia who contracted vaccine-associated poliomyelitis. Poliovirus type 2 was isolated from the initial stool specimen. In our patient, temporary changes in the cerebrospinal fluid resembled those in patients without immunodeficiencies, although gammaglobulin therapy had not yet been started. Pleocytosis was observed for a short time after viremia, but soon there was a return to normal without antibody production.  相似文献   
45.
46.
Urinary levels of a,-microglobulin (αlM) and of ulinastatin (UT) and the αlM/UT ratio did not differ significantly between age-matched controls and patients with Parkinson's disease, and among subdivided groups based on Yahr's stages in Parkinson's disease. Furthermore, these indexes did not correlate with Yahr's stages. Although αlM and UT levels did not correlate in patients with Parkinson's disease, a positive correlation was observed in the control group. The non-existence of a positive correlation between αlM and UT levels distinguishes Parkinson's disease from other neuropsychiatric diseases such as dementia (Alzheimer-type and vascular dementia), schizophrenia and mood disorder.  相似文献   
47.
48.
49.
3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5 H )-furanone (MX) is known as a by-product of wood pulp manufacture and a contaminant of chlorinated drinking water. Since our previous studies (Teramoto et al., 1998, 1999) demonstrated in a micromass in vitro test a strong inhibitory effect of MX on rat embryo cell differentiation, the potential teratogenicity was investigated in this study by using a suspension organ culture system. Twelve-day mouse embryo palatal explants were cultivated for 72 hr in the MX-containing medium at a concentration of 0, 1, 10, 100 or 300 μg/ml and examined for closure of the palatal shelves. All control explants showed almost complete closure of the palatal shelves. Similar results were also obtained in the MX-treated explants at concentrations up to and including 100 μg/ml. Immunohistochemistry revealed no difference between the control and MX-treated explants in distribution of PCNA-and TUNEL-positive cells in the palatal mesenchyme and medial edge epithelium, respectively. When the MX concentration was raised to 300 μg/ml, palatal shelves remained wide open. However, histopathology revealed extensive pyknosis of the mesenchymal cells and loss of the epithelium. These results may indicate that MX is cytotoxic against the mouse palate at a high concentration, and that it has no cleft-palate inducing effects in mice.  相似文献   
50.
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