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   699篇
  免费   29篇
  国内免费   47篇
耳鼻咽喉   2篇
儿科学   39篇
妇产科学   3篇
基础医学   61篇
口腔科学   11篇
临床医学   95篇
内科学   215篇
皮肤病学   20篇
神经病学   37篇
特种医学   144篇
外科学   24篇
综合类   24篇
预防医学   7篇
眼科学   5篇
药学   54篇
中国医学   3篇
肿瘤学   31篇
  2023年   2篇
  2021年   4篇
  2020年   3篇
  2019年   2篇
  2018年   4篇
  2017年   7篇
  2016年   4篇
  2015年   20篇
  2014年   16篇
  2013年   19篇
  2012年   7篇
  2011年   9篇
  2010年   30篇
  2009年   26篇
  2008年   11篇
  2007年   45篇
  2006年   12篇
  2005年   8篇
  2004年   9篇
  2003年   6篇
  2002年   19篇
  2001年   18篇
  2000年   11篇
  1999年   15篇
  1998年   47篇
  1997年   48篇
  1996年   55篇
  1995年   30篇
  1994年   31篇
  1993年   20篇
  1992年   9篇
  1991年   11篇
  1990年   8篇
  1989年   33篇
  1988年   27篇
  1987年   21篇
  1986年   21篇
  1985年   15篇
  1984年   14篇
  1983年   6篇
  1982年   15篇
  1981年   11篇
  1980年   14篇
  1979年   4篇
  1978年   5篇
  1977年   5篇
  1976年   6篇
  1975年   7篇
  1931年   1篇
  1925年   1篇
排序方式: 共有775条查询结果,搜索用时 15 毫秒
41.
42.
Objective: The guiding criteria are considered the backbone of Chinese medicine. They have previously been described as functional features (symptoms) leading to the overall assessment of human functions on the basis of a regulatory (cybernetic) model referring to the I Ging. Methods: The Heidelberg model can explain symptoms such as created by "heat" on a rational physiological level. Results & Conclusion: The overall of physiological symptoms are shown as a schematic draft. The basis of "heat" is considered to be a general increase of microcirculation in the periphery. This leads to a couple of local pathophysiological consequences and sensations like 1) red tongue (the tongue is considered an embryological somatotopic system). 2) Sensation of warmth (by increase of capillary flow). 3) pre-inflammatory state, leading to pain modalities like "worse if pressed", as inflammations tend to be increasingly painful under pressure; 4) reddish skin, the mechanisms by which this is induced may include the release of substance P, therefore accompanied by burning sensation. Systemic pathophysiological consequences may include. Relative lack of fluid in the larger vessels, as fluid supplies peripheral capillary flow. This may lead to water saving mechanisms like thirst, dry mucosa with do, mouth, dry nose, dry lips, dry skin, and also dry stool, yellow and sparse urine.  相似文献   
43.
OBJECTIVES: To further examine the role of proteolytic enzyme expression of matrix metalloproteinases (MMP) and T-cell markers in inflammatory myopathies and controls. MATERIAL AND METHODS: We studied the expression of MMP-2, MMP-7, and MMP-9 in 19 cases of inflammatory myopathies and controls using immunocytochemistry. RESULTS: Inflammatory myopathies showed distinct patterns of up-regulation of MMP. MMP-9 was strongly expressed in atrophic myofibers in all inflammatory myopathies. MMP-2 immunoreactivity was similar in its distribution, however, to a weaker intensity. In dermatomyositis the perifascicular atrophy showed pronounced MMP-9 immunoreactivity, probably reflecting denervated patterns of myofibers. Moreover, MMP-7 strongly immunolabeled invaded myofibers in polymyositis cases only. CONCLUSION: These patterns confirm, that MMP-7 up-regulation is prominent in PM, while MMP-2 immunoreactivity is only slightly elevated in inflamed muscle. In general, MMP-9 up-regulation appears to be an important additional molecular event in the multistep process of all inflammatory myopathies.  相似文献   
44.
The intensive care unit at Queen Elizabeth Central Hospital (QECH) has 4 beds and offers level 2 care. A retrospective audit of all admissions to the unit during 2002 was carried out. There were a total of 339 admissions giving a bed occupancy rate of 82 %. Surgical patients made up 81 % of admissions. 45% of all admissions were ventilated. Overall mortality was 38%. Ventilated patients had a mortality of 71% compared with 10% for non-ventilated. Data are also presented for mortality within the surgical and paediatric surgical admissions.  相似文献   
45.
Summary. During the treatment of four patients with cerebral manifestation of Wilson's disease, we measured the copper concentration in the cerebrospinal fluid (CSF) and serum, the serum coeruloplasmin concentration, the free copper concentration in the serum, and the albumin ratio CSF/serum (AR). These measurements were treated as indicators of the copper-related toxic effects on the brain and the blood-brain barrier (BBB). The half – life of the decrease in the CSF copper concentration during therapy was 23.5 ± 5.78 months (mean ± S.E.M.). The therapeutic – target – copper concentration in the CSF (mean normal concentration) is below 20 μg/l. The average length of therapy needed to normalize CSF – copper values in our patients with an average initial value of 76.25 μg/L was 47 month. During the first 10 month of treatment there was an increase in all cases of the measured disturbance in the blood-brain barrier (measured as the ratio of albumin in CSF to albumin in serum, AR). All patients showed an initial worsening of the neurological condition, on average after 1.75 ± 0.25 months. The maximal rise in AR, from the initial values, was on average 18.4 ± 5.08%; this maximum was reached after an average of 6.9 ± 1.5 months. The AR normalized during therapy, indicating a reduction in toxicity in the blood-brain barrier region. The extent of the AR increases in individual patients did not correlate significantly with CSF copper half-life, serum copper half-life, the initial half – life of the reduction in the ratio (copper in serum)/(coeruloplasmin in serum), the initial copper concentration in CSF or serum, the initial free copper concentration in serum, or the initial dose of penicillamine (within the first 2 months). We conclude that the normalization of the CSF copper concentration in patients with the cerebral manifestation of Wilson's disease is a slow process, even if therapy is sufficient. The initial worsening of the neurological condition which has often been reported may be reflected in the disturbance of blood-brain barrier function, which we have measured here for the first time (using the parameter of the albumin ratio CSF/serum). Based on repeated measurements of the AR during the course of treatment it seems that the brain toxicity of mobilized copper can be assessed and the therapy adjusted. Received April 21, 1999; accepted August 18, 1999  相似文献   
46.
E mu-pim-1 transgenic mice are predisposed to develop lymphomas. Due to their low spontaneous tumour incidence and their increased sensitivity towards the lymphomagen ethylnitrosourea these mice may present an interesting model for short-term carcinogenicity testing. Here, we report on the further exploration of this transgenic mouse model with two additional carcinogens known to have, among others, the lymphohaematopoietic system as target, i.e. benzo[a]pyrene (B[a]P) and 12-O-tetradecanoylphorbol-13-acetate (TPA). B[a]P, given three times a week (by gavage) for 13 weeks at 4.3, 13 or 39 mg/kg body weight, resulted in a dose-related increase in lymphomas up to a 90% incidence in E(mu)-pim-1 mice during the observation period of 40 weeks. B[a]P also induced tumours of the forestomach within this observation period, though at a lower incidence and apparently equally effective in wildtype and transgenic mice. TPA, on the other hand, was unable to induce lymphomas (or tumours in any other organ) in either transgenic or wildtype animals within the observation period of 44 weeks, when applied dermally at the maximum tolerated dose of 3 microg/mouse, twice a week for 35 weeks. Molecular analysis showed that B[a]P-induced lymphomas in transgenic mice were of T-cell origin, 80% of which had elevated levels of c-myc expression. None of the lymphomas had increased N-myc expression and mutation analysis of the ras-gene family revealed a K-ras mutation in only one out of eight tumours investigated. Also, none of the lymphomas showed aberrant expression of p53 as determined by immunohistochemistry. It is concluded that the E mu-pim-1 mouse model will not be very suitable for short-term carcinogenicity testing in general: only genotoxic chemicals that have the lymphohaematopoietic system as target for carcinogenesis in wild- type mice, appear to be efficiently identified.   相似文献   
47.
Mucormycosis is a rare fungal infection of childhood, occurring mainly in patients with chronic illnesses such as diabetes and malignancies. The fungus seldom grows in culture and confirmation of the diagnosis depends on histologic examination of infected tissues. To date, the reported natural history of the disease has been rapid progression and a fatal outcome. Therefore, the importance of early diagnosis by tissue biopsy and early treatment with surgical debridement and systemic antifungal therapy cannot be overemphasized. The pulmonary system is the most common site for mucormycosis in patients with leukemia. We report what we believe to be the first successfully treated case of isolated muscular mucormycosis occurring in a child with biphenotypic acute leukemia. The diagnosis was made promptly by tissue examination at the time of surgical debridement. The patient was also given systemic amphotericin-B therapy.   相似文献   
48.
Data on body composition in conjunction with reference centiles are helpful in identifying the severity of growth and nutritional disorders in infancy and for evaluating the adequacy of treatment given during this important period of rapid growth. Total body fat (TBF) and fat-free mass (FFM) were estimated from total body electrical conductivity (TBEC) measurements in 423 healthy term Caucasian infants, aged 14-379 days. Cross sectional age, weight, and length related centile standards are presented for TBF and FFM. Centiles were calculated using Altman's method, based on polynomial regression and modelling of the residual variation. The TBF percentage steeply increased during the first half year of life, and slowly declined beyond this age. Various simple TBEC derived anthropometric prediction equations for TBF and FFM are available to be used in conjunction with these standards. Regression equations for the P50 and the residual SD, depending on age, weight, or length, are provided for constructing centile charts and calculating standard deviation scores.  相似文献   
49.
50.
Concepts necessary to an understanding of the basics of quality assurance audits are presented. Included are specific examples that bridged theory and practice by applying the protocol to a real-life diagnostic imaging situation. This method meets the present requirements of the Joint Commission of the Accrediation of Hospitals.  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