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   1418篇
  免费   88篇
  国内免费   50篇
耳鼻咽喉   5篇
儿科学   42篇
妇产科学   11篇
基础医学   213篇
口腔科学   10篇
临床医学   132篇
内科学   228篇
皮肤病学   53篇
神经病学   121篇
特种医学   97篇
外科学   131篇
综合类   67篇
预防医学   95篇
眼科学   21篇
药学   163篇
中国医学   6篇
肿瘤学   161篇
  2023年   9篇
  2022年   11篇
  2021年   25篇
  2020年   24篇
  2019年   23篇
  2018年   28篇
  2017年   14篇
  2016年   25篇
  2015年   40篇
  2014年   52篇
  2013年   40篇
  2012年   69篇
  2011年   70篇
  2010年   47篇
  2009年   59篇
  2008年   71篇
  2007年   78篇
  2006年   64篇
  2005年   59篇
  2004年   64篇
  2003年   51篇
  2002年   44篇
  2001年   42篇
  2000年   31篇
  1999年   35篇
  1998年   25篇
  1997年   31篇
  1996年   12篇
  1995年   16篇
  1994年   20篇
  1993年   22篇
  1992年   25篇
  1991年   25篇
  1990年   27篇
  1989年   16篇
  1988年   13篇
  1987年   16篇
  1986年   19篇
  1985年   18篇
  1984年   16篇
  1983年   15篇
  1982年   11篇
  1978年   9篇
  1976年   18篇
  1975年   10篇
  1974年   8篇
  1973年   11篇
  1972年   11篇
  1970年   14篇
  1967年   8篇
排序方式: 共有1556条查询结果,搜索用时 15 毫秒
71.
72.
73.
Background Various laser and light therapy have been increasingly used for the treatment of acne vulgaris. Patients and methods Twenty patients with facial acne were treated using intense pulsed light (IPL) on one side of the face and pulsed dye laser (PDL) on the other to compare the efficacy and safety of IPL and PDL. Treatment was performed 4 times at 2‐week intervals. Treatment effectiveness was determined using lesion counts, acne severity, patient subjective self‐assessments of improvement, and histopathological examinations, which included immunohistochemical staining for transforming growth factor‐β (TGF‐β). Results Numbers of total acne lesions decreased following both treatments. For inflammatory lesions such as papules, pustules and nodules, IPL‐treated sides showed an earlier and more profound improvement than PDL‐treated sides. However, at 8 weeks after the 4th treatment, a rebound aggravation of acne was observed on IPL‐treated sides. On the contrary, PDL produced gradual improvements during the treatment sessions and these improvements lasted 8 weeks after the 4th treatment. Non‐inflammatory lesions as open and closed comedones also showed improvement following both treatments and PDL‐treated sides showed better improvement as the study proceeded. Histopathological examinations showed amelioration in inflammatory reactions and an increase in TGF‐β expression after both treatments, which were more prominent for PDL‐treated sides. Conclusion Both PDL and IPL were found to treat acne effectively, but PDL showed a more sustained effect. TGF‐β might play a key role in the resolution of inflammatory acne lesions.  相似文献   
74.
Approach to the management of pleural effusion in malignancy   总被引:1,自引:0,他引:1  
The diagnostic and therapeutic approaches to malignant pleural effusions are reviewed, and data on the retrospective study of 37 patients are presented with respect to diagnosis and management. All patients with stable effusions should be managed with systemic therapy for the primary tumor when an effective agent is available. When it becomes necessary to use local therapeutic measures, thoracostomy tube drainage with local instillation of tetracycline is recommended.  相似文献   
75.
76.
77.
Complement is necessary for defense against lung infection with Pseudomonas aeruginosa in mice. We studied in vitro interactions between complement and P. aeruginosa and in vivo effects of complement depletion to better understand this relationship. In vitro, P. aeruginosa strain UI-18 was resistant to killing by mouse serum. However, C3 opsonized the organism (via the alternative and mannose binding lectin [MBL] pathways), and C5 convertase activity on the bacterial surface was demonstrated. In vivo, compared with normal mice, complement-deficient mice experienced higher mortality and failed to sterilize their bronchoalveolar space within 24 h of inoculation. These changes did not seem to be a result of decreased inflammation because complement-deficient mice had normal neutrophil recruitment, greater lung myeloperoxidase content, and, by 24 h, a 35-fold higher level of the CXC chemokine KC. Lung static pressure-volume curves were abnormal in infected animals but were significantly more so in complement deficient mice. These data indicate that although P. aeruginosa is resistant to serum killing, C3 opsonization and C5 convertase assembly occur on its surface. This interaction in vivo plays a central role in host survival beyond just recruitment and activation of phagocytes and may serve to limit the inflammatory response to and tissue injury resulting from bacterial infection.  相似文献   
78.
Objectives and design:  In this study, we examine the relationship between C5a and activation of cysteine aspartic acid protease 8 (caspase 8) in human umbilical vein endothelial cells (HUVEC). Materials or subjects:  Primary cultures of HUVEC were used. Treatments:  Recombinant human C5a (50 ng/ml) was used in the presence or absence of 10 μg/ml cycloheximide (CHX). Methods:  HUVEC were treated with C5a alone and in the presence of CHX, then monitored for cell viability, poly- ADP-ribose 1 (PARP-1) and caspase 8 activities. Gene and protein expressions were assessed for caspase 8 and the caspase 8 homologue, FLICE –inhibitory protein (cFLIP). Results:  We found a 43.1 ± 6.9 percent reduction in viability of HUVEC stimulated for 18 h with 50 ng/ml C5a in the presence of 10 μg/ml CHX (p < 0.05). In contrast, the cell viability of cells stimulated for 18 h with 50 ng/ml C5a or 10 μg/ml CHX alone was not significantly different compared to the non-stimulated control. Treatment of HUVEC with C5a induced an increase in caspase 8 activity but did not significantly affect cFLIP levels. Conclusions:  These data suggest caspase 8 activation induced by C5a leads to cell death if protein synthesis of antiapoptotic protein(s) is blocked. Received 23 July 2008; returned for revision 10 September 2008; received for final revision 29 September 2008; accepted by M. Parnham 18 September 2008  相似文献   
79.
BACKGROUND: The clinical usefulness of amiodarone for the treatment of cardiac arrhythmias is limited by multiorgan toxicity, especially pulmonary and hepatic. There are conflicting reports in the literature regarding the role of free radicals in the initiation of amiodarone-induced toxicity. We evaluated the possible oxidative stress in a chronic model that is known to manifest pulmonary toxicity. METHODS AND RESULTS: A group of 20 Fischer-344 rats were injected with 60 mg/kg/day of amiodarone for 21 days. A control group of 20 animals received only saline injections. The alveolar macrophages obtained by lung lavage were incubated with hydroethidine and opsonized green fluorescent zymosan particles to measure oxidative and phagocytic activities by flow cytometry. Malondialdehyde levels were measured to assess the extent of lipid peroxidation in lung, liver, spleen, kidney, and heart. Total phospholipid levels in all the collected tissues and distribution of phospholipid classes in the lung and the liver were measured. The levels of amiodarone and its metabolite desethylamiodarone in serum and all collected tissues were measured by high-performance liquid chromatography. The phagocytic activity of th emacrophages from treated animals was decreased by 18-22% (P <.03) compared to controls; however, the oxidative activities of control and treated groups were not significantly different. The tissue malondialdehyde levels were not significantly different except in the spleen where they increased after amiodarone treatment (18.2 +/- 1.1 vs 23.7 +/- 2.8 μM/g tissue, P <.0001). Malondyaldehyde levels were not significantly different when normalized to lipid phosphorous content. Lung, liver, and spleen showed significantly higher phospholipid levels in the treated group. The tissue amiodarone and desethylamiodarone levels in the treated group were highest in spleen followed by lung, liver, kidney, and heart. CONCLUSIONS: The results show that amiodarone-induced pulmonary and hepatic toxicity is not directly mediated by oxidative stress; however, increased lipid peroxidation in the spleen, although secondary to phospholipidosis, may be physiologically significant.  相似文献   
80.
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