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   3385110篇
  免费   252122篇
  国内免费   5016篇
耳鼻咽喉   47167篇
儿科学   111098篇
妇产科学   93832篇
基础医学   491710篇
口腔科学   96801篇
临床医学   305958篇
内科学   649201篇
皮肤病学   74112篇
神经病学   270127篇
特种医学   129201篇
外国民族医学   902篇
外科学   508921篇
综合类   76490篇
现状与发展   13篇
一般理论   1299篇
预防医学   267275篇
眼科学   79316篇
药学   253624篇
  13篇
中国医学   6359篇
肿瘤学   178829篇
  2018年   35772篇
  2017年   27245篇
  2016年   30533篇
  2015年   34721篇
  2014年   48783篇
  2013年   73904篇
  2012年   101075篇
  2011年   107341篇
  2010年   63771篇
  2009年   60480篇
  2008年   101336篇
  2007年   107746篇
  2006年   108943篇
  2005年   106001篇
  2004年   102523篇
  2003年   98202篇
  2002年   95838篇
  2001年   151203篇
  2000年   155954篇
  1999年   131878篇
  1998年   38345篇
  1997年   33979篇
  1996年   33965篇
  1995年   32494篇
  1994年   30203篇
  1993年   28512篇
  1992年   105524篇
  1991年   103172篇
  1990年   100779篇
  1989年   97393篇
  1988年   90171篇
  1987年   88527篇
  1986年   83708篇
  1985年   80628篇
  1984年   60450篇
  1983年   51847篇
  1982年   30773篇
  1981年   27747篇
  1979年   56805篇
  1978年   40222篇
  1977年   33744篇
  1976年   32147篇
  1975年   34381篇
  1974年   41601篇
  1973年   39786篇
  1972年   37135篇
  1971年   35072篇
  1970年   32345篇
  1969年   30732篇
  1968年   28097篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A study has been carried out on the possible pharmaceutical use of spanish talcs following the normalized assays of the main european pharmacopoeia and other quantitative methods. Only the talc nr3, not processed, meets all the assays of pharmacopoeia. The samples 2 and 4 (crushed) exceed the highest tolerated content in chlorides. The talc 1 (also crushed) only meets the loss on drying. The measures of some of these assays by using quantitative methods lead to more correct results and even sometimes in opposition with those obtained by pharmacopoeia methods. The particle size estimated by shifting and sedimentation shows that the crushed talcs are silty, whereas the only talc not processed is sandy. Considering the medium sizes estimated by scanning microscopy, it can be said that the pulverization of the talcs 1, 2 and 4 is characteristic of a micronization.  相似文献   
992.
In open chest dogs myocardial ischemia was induced by formation of an occlusive thrombus in the left anterior circumflex artery (LCX). Reperfusion of the LCX was achieved by infusion of the fibrin specific recombinant single-chain urokinase-type plasminogen activator (r-scu-PA). The myocardial salvage by r-scu-PA alone and in combination with the epoprostenol (prostacyclin) analog taprostene (CG 4203) was compared. There were four experimental groups: group 1 (n = 4) did not receive any treatment after LCX thrombosis; in group 2 (n = 9) at 100 min after LCX thrombosis r-scu-PA (20 micrograms.kg-1.min-1 i.v. for 30 min) was infused; in groups 3 and 4 treatment with taprostene started concomitantly with r-scu-PA infusion. The taprostene infusions lasted for 120 min and the doses were 0.1 microgram.kg-1.min-1 in group 3 (n = 6) and 0.215 microgram.kg-1.min-1 in group 4 (n = 6). Time to r-scu-PA-induced recanalisation ranged from 18-22 min with no significant difference between groups 2-4. Percent of left ventricle at risk did not differ between the groups. Infarct size as percent of the risk zone was 48.3 +/- 7.7 in group 1, 25.3 +/- 3.7 in group 2, 21.3 +/- 6.5 in group 3 and 17.1 +/- 3.5 in group 4 (p less than 0.05 groups 2-4 vs group 1). Incidence of ectopic beats increased after r-scu-PA-induced reperfusion in groups 2-4, but was significantly reduced by taprostene.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
993.
994.
995.
A total of 42 patients with recurrent superficial bladder tumors or carcinoma in situ entered a prospective, randomized trial to compare the efficacy of bacillus Calmette-Guerin therapy with and without quarterly maintenance instillations of bacillus Calmette-Guerin. Maintenance therapy did not reduce further bladder tumor recurrence rates or the interval to recurrence in patients who responded to the initial course of therapy. However, prolongation of toxicity was observed with maintenance bacillus Calmette-Guerin therapy.  相似文献   
996.
997.
Kojic amine [2-(aminomethyl)-5-hydroxy-4H-pyran-4-one], an analogue of gamma-aminobutyric acid (GABA), produced dose-related, but short-lived, antinociceptive activity in the 48 degrees C [ED50 = 9.2 (8.2-10.3) mg/kg i.p.] and 55 degrees C [ED50 = 13.8 (12.2-15.7) mg/kg i.p.] hot-plate tests in the mouse. The antinociceptive activity of kojic amine at 48 degrees C was found to be insensitive to bicuculline (1.0 mg/kg i.p.) and picrotoxin (0.5 mg/kg i.p.). At this temperature, antinociception was distinctly separate from the impairment of motor function (measured by a rotorod assay) and was not significantly affected by prior treatment with the cholinergic antagonist, atropine sulfate (10.0 mg/kg i.p.). However, at 55 degrees C, the antinociceptive effect of a large dose (20 mg/kg i.p.) of kojic amine was significantly attenuated by similar pretreatment with atropine sulfate, but not by the peripheral cholinergic antagonist, atropine methylnitrate (10.0 mg/kg i.p.). Kojic amine exhibited no significant interaction with haloperidol (0.5 mg/kg i.p.) at this temperature. In animals made tolerant to morphine, THIP or baclofen, there was analgesic cross-tolerance between kojic amine, morphine and baclofen but not between kojic amine and THIP. It is suggested that kojic amine-induced antinociception is similar to that produced by both THIP and baclofen. Thus, kojic amine represents a unique tool with which to study GABA-ergic antinociceptive processes.  相似文献   
998.
Computed tomography of the brain in the Smith-Lemli-Opitz syndrome   总被引:1,自引:0,他引:1  
Computed tomographic (CT) scans of the brain in a child with Smith-Lemli-Opitz syndrome revealed enlargement of the ventricular system, hypoplasia of the cerebellum, and abnormal thickening of the gray matter, consistent with pachygyria. These findings have been previously noted in autopsies performed on patients with this disorder. We conclude that CT scanning is a valuable tool in the evaluation of children suspected of having the Smith-Lemli-Opitz syndrome.  相似文献   
999.
Intracranial venous thrombosis has been described in newborns, but there have been no reports of intractable neonatal seizures due to this condition. We report cortical venous sinus thrombosis in two term neonates who presented with seizures in the first 24 hours of life. The diagnosis was made by cranial computed tomography and was confirmed by cerebral angiography. Both patients improved clinically after the intracranial venous thrombosis resolved. These patients demonstrate that intracranial venous thrombosis should be considered in the differential diagnosis of neonatal seizures.  相似文献   
1000.
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