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   2592532篇
  免费   184819篇
  国内免费   7574篇
耳鼻咽喉   34334篇
儿科学   85321篇
妇产科学   71783篇
基础医学   364383篇
口腔科学   69697篇
临床医学   234941篇
内科学   516621篇
皮肤病学   62578篇
神经病学   213987篇
特种医学   99985篇
外国民族医学   736篇
外科学   386807篇
综合类   50409篇
现状与发展   5篇
一般理论   969篇
预防医学   196466篇
眼科学   56762篇
药学   188241篇
  8篇
中国医学   5335篇
肿瘤学   145557篇
  2021年   20205篇
  2019年   20760篇
  2018年   29454篇
  2017年   22719篇
  2016年   26364篇
  2015年   29623篇
  2014年   40634篇
  2013年   60670篇
  2012年   80576篇
  2011年   84880篇
  2010年   51251篇
  2009年   49358篇
  2008年   79359篇
  2007年   84156篇
  2006年   85849篇
  2005年   82010篇
  2004年   78975篇
  2003年   76259篇
  2002年   73510篇
  2001年   128429篇
  2000年   131344篇
  1999年   110512篇
  1998年   31277篇
  1997年   27942篇
  1996年   28231篇
  1995年   27402篇
  1994年   25085篇
  1993年   23431篇
  1992年   85164篇
  1991年   81575篇
  1990年   78789篇
  1989年   76066篇
  1988年   69474篇
  1987年   68001篇
  1986年   63543篇
  1985年   60514篇
  1984年   44949篇
  1983年   37947篇
  1982年   22460篇
  1981年   19987篇
  1979年   38961篇
  1978年   27445篇
  1977年   23255篇
  1976年   21497篇
  1975年   22813篇
  1974年   26787篇
  1973年   25372篇
  1972年   23751篇
  1971年   21955篇
  1970年   20187篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
93.
94.
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction.  相似文献   
95.
96.
97.
98.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
99.
Acute lung injury (ALI) caused by systemic inflammatory response remains a leading cause of morbidity and mortality in critically ill patients. Management of patients with sepsis is largely limited to supportive therapies, reflecting an incomplete understanding of the underlying pathophysiology. Furthermore, there have been limited advances in the treatments for ALI. In this study, lung function and a histological analysis were performed to evaluate the impact of transient receptor potential vanilloid‐1 receptor (TRPV1) antagonist (capsazepine; CPZ) on the lipopolysaccharide (LPS)‐induced lung injury in mice. For this, adult mice pre‐treated with CPZ or vehicle received intraperitoneal injections of LPS or saline and 24 hr after, the mice were anaesthetized, and lung mechanics was evaluated. The LPS‐challenged mice exhibited substantial mechanical impairment, characterized by increases in respiratory system resistance, respiratory system elastance, tissue damping and tissue elastance. The pre‐treatment with CPZ prevented the increase in respiratory system resistance and decreased the increase in tissue damping during endotoxemia. In addition, mice pre‐treated with CPZ had an attenuated lung injury evidenced by reduction on collapsed area of the lung parenchyma induced by LPS. This suggests that the TRPV1 antagonist capsazepine has a protective effect on lung mechanics in ALI during endotoxemia and that it may be a target for enhanced therapeutic efficacy in ALI.  相似文献   
100.
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