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   25718篇
  免费   528篇
  国内免费   48篇
耳鼻咽喉   750篇
儿科学   520篇
妇产科学   2086篇
基础医学   3618篇
口腔科学   1008篇
临床医学   977篇
内科学   4835篇
皮肤病学   782篇
神经病学   2264篇
特种医学   364篇
外科学   2607篇
综合类   90篇
一般理论   1篇
预防医学   1693篇
眼科学   1086篇
药学   2917篇
中国医学   30篇
肿瘤学   666篇
  2022年   411篇
  2021年   697篇
  2020年   181篇
  2019年   289篇
  2018年   493篇
  2017年   317篇
  2016年   349篇
  2015年   399篇
  2014年   580篇
  2013年   783篇
  2012年   1024篇
  2011年   1160篇
  2010年   586篇
  2009年   349篇
  2008年   733篇
  2007年   950篇
  2006年   1050篇
  2005年   950篇
  2004年   1029篇
  2003年   998篇
  2002年   839篇
  2001年   691篇
  2000年   678篇
  1999年   565篇
  1998年   175篇
  1992年   371篇
  1991年   323篇
  1990年   361篇
  1989年   407篇
  1988年   466篇
  1987年   450篇
  1986年   459篇
  1985年   435篇
  1984年   350篇
  1983年   256篇
  1979年   530篇
  1978年   317篇
  1977年   256篇
  1976年   248篇
  1975年   342篇
  1974年   512篇
  1973年   516篇
  1972年   432篇
  1971年   409篇
  1970年   388篇
  1969年   409篇
  1968年   355篇
  1967年   274篇
  1966年   291篇
  1965年   176篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
AIM: To check on reproducibility of parameters of the cutaneous electrogastrogram registered at a close or a distant time span. METHODS: Twenty-two volunteers recruited by an advertisement (11 females and 11 males, median age 25 years, range: 18-35) underwent three surface electrogastrography examinations of which two were taken on consecutive days and the third one was accomplished at least 2 weeks before or after the two other sessions. The examination involved a 30-min fasted recording, followed by a 90-min postprandial registration after intake of a 394-kcal mixed solid-liquid test meal. RESULTS: Parameters of the electrogastrogram pertaining to the frequency of the gastric slow waves exhibited good to moderate reproducibility, whereas fair reproducibility characterized parameters expected to describe the power of gastric slow waves. With the exception of the difference fed minus fasted power (DeltaDP), in no instance was the medium term reproducibility any worse than the short term one. Categorical data analysis revealed that the relative time share of normogastria postprandially exhibited a better reproducibility than in the fasted period. The Cohen's kappa-value of 0.459 for the DeltaDP for the medium term reproducibility placed this parameter within the range of moderate agreement between repeat examinations. Of the two two-parameter combinations considered, the alliance of the fasted and fed normogastria performed worse than any of those parameters considered alone, whereas a combination of the DeltaDP with the fed-state normogastria revealed a kappa-value amounting to 0.510 for the medium term reproducibility. CONCLUSIONS: The feasibility of some electrogastrographic parameters to convey clinically useful information may be hampered by their fair reproducibility. Recoding of parameters of the cutaneous electrogastrogram from primary continuous to secondary categorical may help achieve a better agreement between repeat examinations.  相似文献   
42.
43.
Extracts from Erodium cicutarium L. Herit were tested for antiviral and interferon inducing properties. Both water extract and methanol extract as well as its fractions were observed to exert antiviral effect in relation to myxoviruses, Herpes virus type 1, Vesicular stomatitis and vaccinia virus. None of these extracts did induce interferon in a suspension of human leukocytes.  相似文献   
44.
45.
The clofibric acid (CPIB) concentration in the rat blood plasma during 14 days of treatment with clofibrate and after cessation of the treatment, was measured and compared with the changes of some NADP-linked dehydrogenases activity. CPIB rapidly accumulates in the plasma during the first two days of clofibrate administration reaching a maximum concentration of about 0.6 mM. Then a linear decrease of the drug concentration was observed. The second day after clofibrate treatment had been completed, CPIB could no longer be detected in the plasma. Liver malic enzyme activity increased constantly up to the third day after cessation of the treatment. There was a decrease of activity which reached its control level on the 32nd day of the experiment. The variation patterns of hexose monophosphate shunt dehydrogenases activity and liver weight were similar to the changes of malic enzyme activity.  相似文献   
46.
47.
48.
49.
Microbial transformation of selected azacarbazoles, compounds noted for their activity as antitumor agents, conducted with Kitasatosporia setae strain resulted in N-methylation of pyridine nucleus of alpha-, beta- and gamma-carboline molecule. Formed quaternized intermediates were converted in alkaline conditions into corresponding iso-carbolines. The structure of the final products, alpha-, beta- and gamma-iso-carbolines have been established on the basis of spectral data and confirmed by chemical synthesis.  相似文献   
50.
The paper presents the possibilities of applying the posterior thigh flap in the treatment of ischial pressure sores. Between 2000 and 2004 the flap was used in three cases treated in the Orthopaedics and Traumatology Department of the Medical Universtity in Bialystok. The indications, contraindications, operative technique and advantages of the posterior thigh flap are described. In all three cases the ischial bed sores healed well without recurrences. The posterior fasciocutaneous pedicled flap is a good method of treatment for not too extensive bed sores in the ischial region.This flap can be applied in recurrences found after primary bed sore treatment with another method. However the fasciocutaneous flap has a limited range of transposition as compared with cutaneous flaps.  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