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   30篇
  国内免费   13篇
儿科学   22篇
妇产科学   2篇
基础医学   20篇
口腔科学   14篇
临床医学   55篇
内科学   77篇
皮肤病学   4篇
神经病学   6篇
特种医学   178篇
外科学   11篇
综合类   40篇
预防医学   6篇
眼科学   4篇
药学   9篇
  1篇
肿瘤学   23篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2019年   1篇
  2018年   5篇
  2017年   3篇
  2016年   3篇
  2015年   6篇
  2014年   5篇
  2013年   2篇
  2012年   9篇
  2011年   9篇
  2010年   8篇
  2009年   10篇
  2008年   1篇
  2007年   13篇
  2006年   11篇
  2005年   10篇
  2004年   5篇
  2003年   10篇
  2002年   3篇
  2001年   6篇
  2000年   1篇
  1999年   5篇
  1998年   24篇
  1997年   23篇
  1996年   17篇
  1995年   23篇
  1994年   20篇
  1993年   33篇
  1992年   4篇
  1991年   3篇
  1990年   9篇
  1989年   17篇
  1988年   21篇
  1987年   34篇
  1986年   21篇
  1985年   20篇
  1984年   8篇
  1983年   12篇
  1982年   6篇
  1981年   12篇
  1980年   12篇
  1979年   1篇
  1978年   7篇
  1977年   5篇
  1976年   2篇
  1975年   5篇
  1971年   1篇
排序方式: 共有472条查询结果,搜索用时 10 毫秒
91.
Breast milk samples from three groups of Brazilian women were evaluated: G1, mothers delivering term babies of low birth weight (n=16); G2, mothers delivering preterm babies of appropriate birth weight (n = 20); G3, mothers delivering term babies of appropriate birth weight ( n = 30). Milk samples were obtained at 48 h and on the 7th, 15th, 30th and 60th days after delivery and they were analyzed for lysozyme and total IgA levels and for the presence of specific antibodies against Poliovirus types I, II, III, Rotavirus, Herpes simplex virus, Varicella zoster and Cytomegalovirus. The groups were not statistically different in relation to mother's age, parity, type of delivery or socio-economic levels. IgA levels were higher in both low-birth-weight groups (G1 & G2) compared to the control group (G3) throughout the study period. Lysozyme levels decreased up to the 15th day, increasing thereafter up to the 60th day in all groups. Specific antibodies were detected throughout the study period, with no differences among groups. We conclude that breast milk composition of mothers delivering low-birth-weight babies (G1 & G2) was similar despite the different gestational ages.  相似文献   
92.
Periodontal bio‐repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad‐based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.  相似文献   
93.
Psoriasis is commonly associated with a co‐existent arthritis known as psoriatic arthritis (PsA). Although there is some treatment overlap for psoriasis and psoriatic arthritis, it is possible that dermatologists may not diagnose or treat appropriately patients who are developing psoriatic arthritis at an early stage of the disease process when joint damage may be preventable. In this article we review the criteria for diagnosis of this sero‐negative arthritis, look at the clinical indications for referral to a rheumatologist and discuss evolving treatment options relevant to both conditions.  相似文献   
94.
Psoriasis is associated with significant physical and psychological burden affecting all facets of a patient’s life – relationships, social activities, work and emotional wellbeing. The cumulative effect of this disability may be self‐perpetuating social disconnection and failure to achieve a ‘full life potential’ in some patients. Health‐related quality of life studies have quantified the burden of psoriasis providing predominantly cross‐sectional data and point‐in‐time images of patients’ lives rather than assessing the possible cumulative disability over a patient’s lifetime. However, social and economic outcomes indicate there are likely negative impacts that accumulate over time. To capture the cumulative effect of psoriasis and its associated co‐morbidities and stigma over a patient’s life course, we propose the concept of ‘Cumulative Life Course Impairment’ (CLCI). CLCI results from an interaction between (A) the burden of stigmatization, and physical and psychological co‐morbidities and (B) coping strategies and external factors. Several key aspects of the CLCI concept are supported by data similar to that used in health‐related quality of life assessments. Future research should focus on (i) establishing key components of CLCI and determining the mechanisms of impairment through longitudinal or retrospective case–control studies, and (ii) assessing factors that put patients at increased risk of developing CLCI. In the future, this concept may lead to a better understanding of the overall impact of psoriasis, help identify more vulnerable patients, and facilitate more appropriate treatment decisions or earlier referrals. To our knowledge, this is a first attempt to apply and develop concepts from ‘Life Course Epidemiology’ to psoriasis research.  相似文献   
95.
96.
The feasibility of in vitro interleukin 2 (IL-2) activation and expansion of mononuclear cells (MNCs) derived from adult patients with acute myelogenous leukemia (ANLL) was studied. Patients' natural killer (NK) and lymphokine-activated killer (LAK) cell activity was compared with that of normal donors in terms of: (a) cytolytic activity (four- hour 51Cr release assay) against an NK-sensitive target (K562), NK- resistant targets (Raji/Daudi), and fresh/cryopreserved autologous and allogeneic leukemic blasts; (b) proliferation and expansion in culture with 1,000 U/mL recombinant IL 2 (rIL 2); and (c) the cell surface phenotype of the cultured cells. In 21 of 24 patients with active disease (AP) MNCs derived from the peripheral blood (PBL) or bone marrow (BM) could be cultured and expanded in the presence of rIL 2. These cultures initially contained between 30% and 50% blasts, and during 2 to 4 weeks of culture destruction of blasts and enrichment of up to 60% in cells with the morphology of large granular lymphocytes (LGLs) was observed. Expansion in culture varied between two- and 100- fold. MNCs from all patients in remission (RP) could be activated by rIL 2 and expanded up to 30-fold after 1 to 3 weeks in culture. NK activity of fresh PBLs from AP was significantly lower than in normal controls, whereas NK activity of RP was within the normal range. High levels of postactivation NK and LAK activity on K562/Raji/Daudi and on fresh/cryopreserved leukemic blasts was generated in approximately 50% of cases of AP and in most RP. Cell surface phenotype studies showed that cultured cells derived from ANLL patients were significantly enriched (up to 40%) in NKH-1 (Leu 19) positive cells, with RP LAK cells also expressing a high proportion of CD16 positive cells (up to 40%). This study has shown that it is feasible to activate and significantly expand killer cells derived from active disease and remission ANLL patients during 1 to 3 weeks culture with IL 2 with good maintenance of cytolytic activity. Both initial NK activity and LAK generation was optimal in remission patients. Based on data from this study, a clinical protocol has been developed for treatment of early relapse ANLL patients with LAK cells cultured for 1 to 3 weeks and systemic IL 2.  相似文献   
97.
Delfino  DV; Patrene  KD; Lu  J; Deleo  A; Deleo  R; Herberman  RB; Boggs  SS 《Blood》1996,87(6):2394-2400
Natural killer (NK) cells develop from the nonadherent cell component of NK long-term bone marrow (BM) cultures (NK-LTBMC). Because these nonadherent cells are depleted of mature NK cells and T cells, but appear to enriched for NK precursors, they were used as a starting population to begin to define the NK precursors that function in NK- LTBMC. As the stromal cell component of NK-LTBMC has been shown to support interleukin (IL)-2-induced, CD44 dependent, NK cell development from nonadherent NK precursors, NK-LTBMC stroma was used in a limiting dilution assay (LDA) to quantitate the precursors. NK-LTBMC in 96-well plates were irradiated (20 Gy) to kill hematopoietic cells (including the NK precursors), seeded with limiting dilutions of the cells to be quantitated, cultured with 500 U/mL IL-2 for 13 days and assayed for development of NK activity by adding 51Cr-labeled YAC-1 cells to the wells and evaluating the release of 51Cr after 4 hours. Flow cytometric analysis, sorting, and quantitation of the nonadherent cell component of NK-LTBMC showed that NK precursors were concentrated in the CD44neg/dim subset that comprised 10% of the "lymphoid" gated cells. When the CD44neg/dim subset was sorted from BM of mice treated with 5- fluorouracil (5-FU) day before (-1FUBM), there were about 30% T cells, but no NK-1.1+ cells. When the T cells were removed by sorting and the CD44neg/dim, alphabeta, gammadelta T-cell receptorneg (TCR-) subpopulation was seeded onto irradiated stroma with IL-2, they proliferated, developed NK activity, became NK-1.1+ and CD44bright and remained alphabeta, gammadelta TCR-. The frequency of NK precursors in this population as estimated from the LDA was about 1/500.  相似文献   
98.
Percutaneous drainage of chest abscesses in children   总被引:1,自引:0,他引:1  
Ball  WS  Jr; Bisset  GS  d; Towbin  RB 《Radiology》1989,171(2):431-576
Seven patients ranging in age from 3 to 18 years underwent percutaneous drainage of eight intrathoracic abscesses. Five of the abscesses were mediastinal or paramediastinal and resulted from esophageal perforation or esophageal anastomotic leakage. The abscesses resolved in each case, with a mean catheter drainage time of 28 days and no need for surgical intervention. Three of the abscesses were intrapulmonary, and each lay adjacent to a pleural surface. All three lung abscesses resolved within 19-24 days, without thoracotomy or wedge resection.  相似文献   
99.
HUMAN RESPIRATORY MUSCLES: SENSATIONS, REFLEXES AND FATIGUABILITY   总被引:1,自引:0,他引:1  
1. Given the importance of the ventilatory ‘pump’ muscles, it would not be surprising if they were endowed with both sensory and motor specializations. The present review focuses on some unexpected properties of the respiratory muscle system in human subjects. 2. Although changes in blood gas tension were long held not to influence sensation directly, studies in subjects who are completely paralysed show that increases in arterial CO2 levels elicit strong sensations of respiratory discomfort. 3. Stretch reflexes in human limb muscles contain a monosynaptic spinal excitation and a long-latency excitation. However, inspiratory muscles show an initial inhibition when tested with brief airway occlusions during inspiration. This inhibition does not depend critically on input from pulmonary or upper airway receptors. 4. Human inspiratory muscles (including the diaphragm) have been considered to fatigue during inspiratory resistive loading. However, recent studies using phrenic nerve stimulation to test the force produced by the diaphragm show that carbon dioxide retention (hypoventilation) and voluntary cessation of loading occur before the muscles become overtly fatigued.  相似文献   
100.
Dietrich  RB; Kangarloo  H 《Radiology》1987,163(2):367-372
Multiplanar images of 62 pelvic lesions in 58 children and adolescents (aged 7 months to 19 years; mean, 10.6 years) were obtained with 0.3-T magnetic resonance (MR) imaging. Lesions were divided into three categories: congenital anomalies, cystic lesions and fluid collections, and neoplasms. MR demonstrated lesions well in all categories. Midline lesions were best imaged sagittally, and lesions of paired structures, axially. The coronal plane was useful in evaluating the superoinferior extent of lesions and in defining the extent of lymphadenopathy. T1-weighted sequences were sufficient to depict most congenital and cystic lesions. T2-weighted sequences were useful in demonstrating the extent of neoplasms and the position of ectopic gonads. Ultrasonography (US) was also performed in 45 cases. MR and US delineated lesions equally well in 25 cases (55.5%), MR was superior in 19 (42.4%), and US was superior in one (2.2%). Computed tomography (CT) was performed in 13 cases. MR and CT delineated lesions equally well in eight cases (61.5%), MR was superior in four (30.8%), and CT was superior in one (7.7%).  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