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   68428篇
  免费   4206篇
  国内免费   762篇
耳鼻咽喉   1313篇
儿科学   787篇
妇产科学   1056篇
基础医学   11744篇
口腔科学   1570篇
临床医学   5914篇
内科学   12687篇
皮肤病学   2441篇
神经病学   4808篇
特种医学   3983篇
外科学   9298篇
综合类   261篇
现状与发展   1篇
一般理论   25篇
预防医学   3046篇
眼科学   1537篇
药学   6365篇
中国医学   822篇
肿瘤学   5738篇
  2023年   374篇
  2022年   1250篇
  2021年   2618篇
  2020年   1264篇
  2019年   1678篇
  2018年   2090篇
  2017年   1653篇
  2016年   2354篇
  2015年   3359篇
  2014年   3895篇
  2013年   4423篇
  2012年   6660篇
  2011年   6131篇
  2010年   3547篇
  2009年   2993篇
  2008年   4216篇
  2007年   3782篇
  2006年   3322篇
  2005年   2951篇
  2004年   2438篇
  2003年   2081篇
  2002年   1755篇
  2001年   1443篇
  2000年   1319篇
  1999年   958篇
  1998年   408篇
  1997年   282篇
  1996年   223篇
  1995年   195篇
  1994年   167篇
  1993年   150篇
  1992年   347篇
  1991年   331篇
  1990年   294篇
  1989年   271篇
  1988年   262篇
  1987年   259篇
  1986年   187篇
  1985年   171篇
  1984年   137篇
  1983年   112篇
  1982年   62篇
  1981年   65篇
  1979年   85篇
  1978年   71篇
  1975年   50篇
  1974年   63篇
  1973年   54篇
  1972年   55篇
  1970年   50篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
41.
42.
A 65-year-old man developed acute limb ischemia, severe abdominal wall and lower limb livedo reticularis following a coronary angiogram. The differential diagnoses of acute limb ischemia and multiple cholesterol emboli syndrome (MCES) are discussed. This work was performed at Long Island Jewish Medical Center, 270-05, 76th Avenue, New Hyde Park, NY 11040.  相似文献   
43.
This article describes a modified suture technique designed for the vertical repair of the anterior horn of the meniscus after arthroscopic decompression of a large meniscal cyst. This procedure comprises of three steps: first, the meniscus was pierced vertically using a suture hook and a No. 0 PDS suture. Second, both ends of the No. 0 PDS on the femoral and tibial surfaces of the meniscus were pulled to the outside of the joint capsule using a spinal needle preloaded with suture material. Finally, a skin incision was made adjacent to the suture materials, and both ends were tied. We recommend this technique not only for the vertical repair of the anterior horn of the meniscus after decompression of large meniscal cyst, but also to repair a longitudinal tear of the meniscus.  相似文献   
44.
Background/purpose: Vitiligo and nevus depigmentosus (ND) present similar hypopigmented macules with significantly different prognoses. Although the distinction between the two diseases is important, differential diagnosis relies on medical history and physical examination, which is far from decisive in some cases. The Mexameter® is an objective skin color-measuring device, and has been reported to provide a reproducible and sensitive means of quantifying small skin color differences. In this study, we investigated the usefulness of a Mexameter® for discriminating these diseases.
Methods: A selection of 202 hypopigmented skin lesions (182 from vitiligo and 20 from ND) were the objects of this study. Using a Mexameter, MIs were obtained from lesions and symmetrically located control skin. RMIs, ratios of the MIs of lesional skins to control skins, were calculated.
Results: The mean MIs and RMIs were significantly different for vitiligo and ND. The mean RMI of ND lesions was 74±13, which was significantly higher than that of vitiligo lesions (50±24). No ND lesion had an RMI of <50%.
Conclusion: This study shows that the Mexameter®, an objective pigment-measuring device, can be used to achieve a more accurate diagnosis of hypopigmentary disorders, and that the relative melanin index (RMI), which represents the relative pigment levels, might be a more effective parameter than the melanin index (MI) itself for comparing pigmentation differences.  相似文献   
45.
46.
47.
48.
Monte Carlo simulation was used to assess the effects of several intervention strategies on coronary heart disease mortality rates in a Finnish and a North American cohort. Lowering total serum cholesterol by 4%, smoking by 15%, and diastolic blood pressure by 3% for the whole cohort would be expected to reduce the incidence of non-fatal myocardial infarction by at least 13% and coronary heart disease deaths by at least 18%. Lowering serum cholesterol by 34%, diastolic blood pressure to 90 mmHg, and reducing smoking by 20% in the subset of the population with all three risk factors in the highest quartile would result in a 6-8% reduction in non-fatal myocardial infarction and a 2-9% reduction in deaths from coronary heart disease in these cohorts. These data demonstrate that in populations with a relatively high incidence of heart disease, treating the entire population will produce larger effects than focusing only on high-risk populations.  相似文献   
49.
Previously, we prepared two different monoclonal antibodies (mAbs) against human 4-1BB (CD137): an agonistic mAb BBK-1 and an antagonistic mAb BBK-2. In this paper, we describe the molecular cloning of these two mAbs and present comparisons of their amino acid sequences. cDNAs encoding the heavy (H) and light (L) chains of the two mAbs were cloned by screening of cDNA libraries constructed from hybridomas secreting these mAbs. Comparisons of amino acid sequences of the two mAbs showed that, while the constant regions of the H and L chains were identical between the two mAbs, the variable region showed 45% identity in H chains and 48% identity in L chains. This suggests that these two mAbs recognize different epitopes of 4-1BB and may have different effects on the activity of 4-1BB.  相似文献   
50.
A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used.  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