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   261498篇
  免费   53998篇
  国内免费   1324篇
耳鼻咽喉   3516篇
儿科学   10081篇
妇产科学   5109篇
基础医学   41421篇
口腔科学   10644篇
临床医学   28260篇
内科学   64222篇
皮肤病学   11643篇
神经病学   30900篇
特种医学   7980篇
外国民族医学   24篇
外科学   34899篇
综合类   2029篇
一般理论   113篇
预防医学   19546篇
眼科学   4283篇
药学   19954篇
  3篇
中国医学   1875篇
肿瘤学   20318篇
  2023年   1258篇
  2022年   2922篇
  2021年   6243篇
  2020年   7938篇
  2019年   14553篇
  2018年   14716篇
  2017年   14810篇
  2016年   15961篇
  2015年   16348篇
  2014年   17876篇
  2013年   20762篇
  2012年   16933篇
  2011年   17443篇
  2010年   16316篇
  2009年   11698篇
  2008年   13128篇
  2007年   12215篇
  2006年   11491篇
  2005年   10675篇
  2004年   10370篇
  2003年   9651篇
  2002年   9315篇
  2001年   4919篇
  2000年   4648篇
  1999年   3716篇
  1998年   1879篇
  1997年   1501篇
  1996年   1330篇
  1995年   1213篇
  1994年   1099篇
  1993年   1003篇
  1992年   2060篇
  1991年   1950篇
  1990年   1679篇
  1989年   1614篇
  1988年   1488篇
  1987年   1311篇
  1986年   1315篇
  1985年   1145篇
  1984年   896篇
  1983年   828篇
  1982年   595篇
  1981年   494篇
  1980年   472篇
  1979年   641篇
  1978年   489篇
  1975年   472篇
  1974年   529篇
  1973年   492篇
  1972年   452篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Gangliocytic paragangliomas are rare tumors that almost exclusively occur within the second portion of the duodenum. Although these tumors generally have a benign clinical course, they have the potential to recur or metastasize to regional lymph nodes. The case report presented here describes a 57-year-old female patient with melena, progressive asthenia, anemia, and a mass in the second-third portion of the duodenum that was treated by local excision. The patient was diagnosed with a friable bleeding tumor. The histologic analysis showed that the tumor was a 4 cm gangliocytic paraganglioma without a malignant cell pattern. In the absence of local invasion or distant metastasis, endoscopic resection represents a feasible, curative therapy. Although endoscopic polypectomy is currently considered the treatment of choice, it is not recommended if the size of the tumor is > 3 cm and/or there is active or recent bleeding. Patients diagnosed with a gangliocytic paraganglioma should be closely followed-up for possible local recurrence.  相似文献   
63.
64.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
65.
66.
67.
68.
The yeast Saccharomyces cerevisiae is a useful model for studying the influence of different stress factors on eukaryotic cells. In this work we used the pesticide imidacloprid, in the Confidor formulation, as the stress factor and analyzed its influence on the metabolic activity, proteome and lipid content and composition of Saccharomyces cerevisiae yeast. During the cultivation of yeast, the lowest recommended application dose of Confidor (0.025%, v/v) was added to the growth media and its influence on the mitochondria, cytosol with microsomes, and the whole yeast cells was monitored. The results show that under the stress provoked by the toxic effects of Confidor, yeast cells density significantly decreased and the percentage of metabolically disturbed cells significantly increased comparing with untreated control. Also, there was a downregulation of majority of glycolytic, gluconeogenesis, and TCA cycle enzymes (Fba1, Adh1, Hxk2, Tal1, Tdh1,Tdh3, Eno1) thus providing enough acetyl‐CoA for the lipid restructuring and accumulation mechanism since we have found the changes in the cell and mitochondrial lipid content and FA composition. This data suggest that lipids could be the molecules that orchestrate the answer of the cells in the stress response to the Confidor treatment.  相似文献   
69.
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   
70.
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