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   1308330篇
  免费   91914篇
  国内免费   1972篇
耳鼻咽喉   18589篇
儿科学   45199篇
妇产科学   35683篇
基础医学   185134篇
口腔科学   33931篇
临床医学   114191篇
内科学   262193篇
皮肤病学   28333篇
神经病学   103160篇
特种医学   51531篇
外国民族医学   660篇
外科学   198124篇
综合类   27293篇
现状与发展   1篇
一般理论   420篇
预防医学   98584篇
眼科学   28355篇
药学   96239篇
  30篇
中国医学   2453篇
肿瘤学   72113篇
  2019年   9922篇
  2018年   13720篇
  2017年   10466篇
  2016年   11410篇
  2015年   12866篇
  2014年   17868篇
  2013年   27230篇
  2012年   37479篇
  2011年   39573篇
  2010年   23616篇
  2009年   22573篇
  2008年   37898篇
  2007年   40609篇
  2006年   40847篇
  2005年   39723篇
  2004年   38834篇
  2003年   37594篇
  2002年   36864篇
  2001年   64145篇
  2000年   66605篇
  1999年   56545篇
  1998年   15339篇
  1997年   13931篇
  1996年   14330篇
  1995年   13582篇
  1994年   12861篇
  1993年   11910篇
  1992年   44630篇
  1991年   43538篇
  1990年   42280篇
  1989年   40175篇
  1988年   36940篇
  1987年   36282篇
  1986年   33658篇
  1985年   32324篇
  1984年   24183篇
  1983年   20331篇
  1982年   11787篇
  1981年   10752篇
  1979年   21381篇
  1978年   14857篇
  1977年   12571篇
  1976年   11734篇
  1975年   12655篇
  1974年   14700篇
  1973年   14159篇
  1972年   12970篇
  1971年   11749篇
  1970年   11068篇
  1969年   10045篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Cultured keratinocytes were used as allografts on burn wounds in two patients. In both patients successful covering of the wounds was obtained. DNA fingerprinting of the epidermis covering the wounds 21 days later showed that the cultured keratinocytes were replaced by the patients' cells.  相似文献   
82.
In experiments on albino rats it was established that three administrations of indomethacin in a dose of 0.01 g/kg body weight induced a severe damage of the liver characterized by disturbances of hepatocytic membranes, bile-producing and protein-producing functions of the liver, an enhancement of lipid peroxidation, a decrease of reduced glutathione pool. Antioxidants (tocopherol acetate, essentiale, legalon, flacumin) limit manifestations of indomethacin, hepatotoxicity, as a result of which tha functional-biochemical disorders in the liver show up to a lesser degree. During the combined use of antioxidants in indomethacin-induced lesions of the liver their hepatoprotective activity increases.  相似文献   
83.
Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident.  相似文献   
84.
85.
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   
86.
87.
Acetaldehyde, the first metabolite of ethanol, reacts with haemoglobinin vitro to produce acetaldehyde—haemoglobin adducts.Some clinical studies on the minor haemoglobins have suggestedthat these adducts may be formed in people abusing alcohol.Under hydrolysis of haemoglobin, with oxalic acid at 100°Cin sealed vials, some acetaldehyde was released and then specificallydetermined by HPLC. The kinetics of hydrolysis were studiedusing haemoglobin previously labelled with 14[C] acetaldehyde.The maximum liberation of 14[C] acetaldehyde was obtained after3 hr 30 min hydrolysis and this time factor was then utilizedin the analysis of alcoholic and control haemoglobin. Thus,we have confirmed the formation of acetaldehyde haemoglobinadducts in vivo. It must be noted that the released acetaldehydecorresponds only to an index of the stable adducts. The levelswere higher in alcoholics than in controls (1.417±0.171and 1.295±0.139 nmol/mg Hb, respectively, P<0.001).In conclusion, this marker is not a convenient tool for themonitoring of alcohol exposure levels because of the low differencesbetween alcoholic and control haemoglobins.  相似文献   
88.
Ticks of the Ornithodoros moubata complex were collected from domestic pig sties and dwelling houses, and from a warthog habitat, and tested for the presence of African swine fever (ASF) virus. Collections were made in 9 of the 24 districts of Malawi, these being primarily the districts in which O. moubata is most numerous. ASF virus was isolated from ticks collected in both domestic pig sties and houses in certain villages in Mchinji district where ASF outbreaks had recently occurred. Mchinji district is in the centre of a large ASF enzootic area which stretches into other districts of Malawi and also into Zambia and Mozambique. The high titre of virus in some of the ticks demonstrates that O. moubata can act as a virus reservoir and potential vector of disease in the field situation in Malawi.  相似文献   
89.
90.
In view of the putative involvement of calcium in uremic encephalopathy and the critical importance of this element in juvenile development, we examined the effect of temporary restriction of dietary calcium intake on serum chemistry and the quantitative electroencephalogram (Q.EEG) in unilaterally 3/4 nephrectomized juvenile male Sprague-Dawley rats. Animals were renally infarcted at 22-26 days of age (50-74 g) and placed on one of two isocaloric dietary regimens: powdered normal rat diet (ND, n = 25) or low calcium diet (LCD, n = 8) for 30 days. At this time, ND animals showed normal serum chemistries, whereas LCD rats were hypocalcemic and azotemic with significantly elevated blood urea nitrogen (BUN) and serum creatinine concentrations and reduced renal creatinine clearance values. All animals thereafter received ND for 25-34 further days, during which time chronic Q.EEG electrodes were implanted. At the end of the common ND feeding period, serum chemistry values were equal and normal in both groups. The average theta/alpha ratio (TAR) of the overnight Q.EEG was assessed for 3 days. We found that the TAR of previously LCD animals was significantly elevated compared with ND rats. This indicates an encephalopathic slowing of the background rhythm of these animals. We conclude that, following restoration of a transient uremic and hypocalcemic episode induced by LCD feeding, the Q.EEG background frequency of juvenile renally impaired rats was abnormally slow after 30 days of ND feeding.  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