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   3217967篇
  免费   240354篇
  国内免费   8171篇
耳鼻咽喉   43697篇
儿科学   104456篇
妇产科学   87204篇
基础医学   462079篇
口腔科学   89444篇
临床医学   292696篇
内科学   629698篇
皮肤病学   73385篇
神经病学   257580篇
特种医学   124063篇
外国民族医学   743篇
外科学   488321篇
综合类   70597篇
现状与发展   14篇
一般理论   1167篇
预防医学   257174篇
眼科学   73462篇
药学   235396篇
  15篇
中国医学   5970篇
肿瘤学   169331篇
  2018年   35055篇
  2017年   26740篇
  2016年   30742篇
  2015年   34575篇
  2014年   48669篇
  2013年   73525篇
  2012年   97252篇
  2011年   103935篇
  2010年   62878篇
  2009年   60047篇
  2008年   97278篇
  2007年   103794篇
  2006年   105161篇
  2005年   102010篇
  2004年   97336篇
  2003年   94193篇
  2002年   90882篇
  2001年   146418篇
  2000年   150268篇
  1999年   126695篇
  1998年   38032篇
  1997年   33517篇
  1996年   34245篇
  1995年   33250篇
  1994年   30743篇
  1993年   28935篇
  1992年   100963篇
  1991年   98527篇
  1990年   95843篇
  1989年   92024篇
  1988年   84924篇
  1987年   83381篇
  1986年   78505篇
  1985年   75497篇
  1984年   56889篇
  1983年   48324篇
  1982年   29343篇
  1981年   26424篇
  1979年   52195篇
  1978年   37565篇
  1977年   31354篇
  1976年   29695篇
  1975年   31623篇
  1974年   37747篇
  1973年   35908篇
  1972年   33767篇
  1971年   31650篇
  1970年   29010篇
  1969年   27625篇
  1968年   25454篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A Brci? 《Hand Clinics》1990,6(2):211-219
The article describes the correct technique of primary tangential excision in deep dermal and third-degree hand burns. The operation performed under tourniquet facilitates the preservation of viable tissue, which is of utmost importance in hand burns. The therapeutic results depend on the extent of destroyed tissue. Primary tangential excision prevents fibrosis due to prolonged infection and impaired circulation, thus creating much more favorable conditions for reconstruction and rehabilitation.  相似文献   
992.
(i) The characteristics of the major human hepatic isoenzymes of aldehyde dehydrogenase (ALDH), ALDH I and ALDH II, were compared with the ALDH activities found in human placenta and erythrocytes, (ii) In human liver biopsies, the Km of ALDH I was approximately 7 mumol/L whereas it was 32 mumol/L for ALDH II. The Vmax for ALDH I was 2-3 times greater than the ALDH II Vmax. Human liver ALDH I and II also differed in their sensitivity in inhibitors. Namely, ALDH I was less sensitive to disulfiram than the ALDH II isoenzyme. (iii) ALDH activity in human placenta and erythrocytes was much lower than in liver tissue. Kinetic data showed that placental ALDH isoenzyme had a high Km (in the millimolar range) and increased its activity raising the pH from 7.4 to 8.8, more than the hepatic ALDH I and ALDH II isoenzymes did. Erythrocyte ALDH activity presented a dual component; the smaller one was characterized by a low Km (micromolar range), whereas most of the ALDH activity showed a high Km (millimolar range). (iv) Placental ALDH was resistant to nitrefazole inhibition and was inhibited by disulfiram in a manner similar to the hepatic ALDH I isoenzyme; erythrocyte ALDH was more sensitive to the inhibitory action of disulfiram and nitrefazole. (v) It is concluded that erythrocyte and placental ALDH isoenzymes are different from the hepatic ALDH I and ALDH II forms. It is also suggested that placental and erythrocyte ALDH isoenzymes are different high-Km isoenzymes.  相似文献   
993.
994.
Treatment of dogs for 21 days with oral levodopa (100 mg b.i.d.) plus benserazide (25 mg b.i.d.) induced a significant increase in the number of platelet alpha 2-adrenoceptors labelled by [3H] yohimbine with no change in Kd. The rise was maximal at the end of the treatment and remained significant during the month following the cessation of treatment. Plasma catecholamine levels did not vary. Competition experiments showed a low affinity of both dopamine and levodopa for platelet alpha 2-adrenoceptors. These results suggest that levodopa treatment regulates alpha 2-adrenoceptor number in dog platelets.  相似文献   
995.
The effect of thymosin fraction 5 and its synthetic component thymosin-alpha 1 administered i. p. and i. c. v. on the behavior of 219 Wistar rats in the open field was studied to establish the effective dose and time of action of both substances. It was shown that at i. c. v. administration of both compounds in a dose of 10 ng the motor activity was suppressed for about 0.5 hour. At i. p. administration thymosin fraction 5 in doses of 0.15, 0.3 and 0.6 mg/kg suppressed the motor activity for more than 2 hours. The higher the dose, the greater the degree of suppression of the motor activity. Both peptides influence in a similar way the motor activity of the animals irrespective of the route of administration.  相似文献   
996.
997.
998.
Fifty-six patients with recurrent bronchopulmonary infections associated with chronic bronchitis were randomly allocated to 2 groups, to assess whether treatment with an immunomodulator, Diribiotin CK, could enhance resistance to infection. The double-blind, placebo-controlled prospective trial over a 9 month period showed that this immunomodulator was well tolerated and significantly reduced the rate of respiratory tract infection. The drug also significantly reduced the prescribing of antibiotic medication and the rate of absenteism from work. These effects have been demonstrated in a rigorously designed clinical study. This is the first time that a clear clinical activity has been attributed to an inducer of soluble mediators of immunity.  相似文献   
999.
1000.
Professional exposure to vegetable dusts affect the respiratory function of the exposed subjects. A previous survey conducted in an industrial flour-mill demonstrated a higher frequency of respiratory symptoms in workers compared to a control group. Ten subjects employed in a work site particularly exposed to dust were studied. Each subject answered a questionnaire and performed on Mondays and Fridays, at the begenning and end of his work shift, a flow volume curve and an isocapnic hyperventilation test. The aerobiology of the professional environment was also measured. We noted: 1) in the flow volume curves: a drop in the FEV1 during the Monday morning shift, a significant difference between the FEV1 (p<0.05) and the MMEFR 25–75 (p<0.05) measured at 6 am on Monday and Friday, and between the MMEFR 25–75 values obtained at 12 noon on Monday and Friday (p<0.05). 2) after isocapnic hyperventilation, a significant drop in the MMEFR 25–75 at 6 am on Monday (p<0.01) and in the FEV1 and MMEFR 25–75 at 12 noon on Mondays (p<0.05), a significant drop in the FEV1 at 1 pm on Monday (p<0.01).  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