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   13378篇
  免费   831篇
  国内免费   29篇
耳鼻咽喉   285篇
儿科学   380篇
妇产科学   179篇
基础医学   1985篇
口腔科学   375篇
临床医学   1368篇
内科学   2540篇
皮肤病学   279篇
神经病学   1124篇
特种医学   516篇
外科学   1823篇
综合类   98篇
一般理论   11篇
预防医学   922篇
眼科学   519篇
药学   1017篇
中国医学   22篇
肿瘤学   795篇
  2023年   94篇
  2022年   110篇
  2021年   202篇
  2020年   186篇
  2019年   259篇
  2018年   259篇
  2017年   257篇
  2016年   271篇
  2015年   307篇
  2014年   362篇
  2013年   548篇
  2012年   681篇
  2011年   755篇
  2010年   413篇
  2009年   404篇
  2008年   663篇
  2007年   678篇
  2006年   654篇
  2005年   587篇
  2004年   589篇
  2003年   564篇
  2002年   430篇
  2001年   443篇
  2000年   391篇
  1999年   344篇
  1998年   178篇
  1997年   130篇
  1996年   126篇
  1995年   110篇
  1994年   99篇
  1993年   64篇
  1992年   185篇
  1991年   173篇
  1990年   176篇
  1989年   167篇
  1988年   143篇
  1987年   131篇
  1986年   119篇
  1985年   121篇
  1984年   88篇
  1983年   82篇
  1982年   63篇
  1980年   55篇
  1979年   87篇
  1978年   72篇
  1977年   79篇
  1975年   57篇
  1974年   61篇
  1973年   56篇
  1972年   81篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Fifty patients with refractory acute lymphoblastic leukemia underwent allogeneic bone marrow transplantation after conditioning with high-dose cytosine arabinoside and fractionated total body irradiation. Twenty-nine received intravenous immunoglobulin (i.v.Ig) infusion, primarily to prevent cytomegalovirus infection, and 21 did not. The two groups were biologically comparable. Seven (24.5%) of the i.v.Ig-treated and 14 (66.7%) of the non-i.v.Ig-treated patients developed systemic viral, fungal or bacterial infections and/or interstitial pneumonitis (p less than 0.005), which were fatal in three and 12 cases respectively (p less than 0.001). Currently, 23 (79.3%) of the 29 i.v.Ig-treated and eight (38.1%) of the 21 non-i.v.Ig-treated patients are alive and well (p less than 0.01). We conclude that prophylactic i.v.Ig infusions may reduce the frequency of all forms of serious infection in patients with acute lymphoblastic leukemia undergoing allogeneic marrow transplantation, and thereby improve their survival expectation.  相似文献   
63.
64.
Bilateral facial palsy is frequently linked with lyme disease. We report a patient with bilateral facial palsy due to Epstein-Barr virus infection but with Borrelia burgdorferi IgM in serum caused by polyclonal B-lymphocyte stimulation.  相似文献   
65.
Abstract: This review examines the liver-damaging side effects of anabolic-androgenic steroids (AAS). It seems that AAS can cause development of peliosis hepatis, subcellular changes of hepatocytes, hepatocellular hyperplasia and hepatocellular adenomas. On the other hand, it has not been convincingly proved that AAS can cause development of hepatocellular carcinomas when used in the usual therapeutic doses. Tumours reported as hepatocellular carcinomas caused by AAS seem to be hyperplastic lesions of a benign nature able to regress with withdrawal of the putative agent. The effects of untraditional combinations and high-dose AAS are not yet known, leaving the possibility of a carcinogenic effect in those cases.  相似文献   
66.
This paper reports a case study of a 10-year-old girl exhibiting symptoms of a Zimmermann-Laband syndrome (ZLS), including an ocular involvement not previously observed. In addition to the case reported, we have also discovered 21 patients described in the literature. Major clinical findings, defined as being present in more than 75% of the cases under discussion, are presented.  相似文献   
67.
We investigated the effects of polymerization heat and toxicity of polymethyimetacrylate bone cement in the canine tibial diaphysis. Heat was studied by filling the tibias with either bone cement or bone wax contained in a monomer tight membrane pouch. Toxicity was studied by filling both tibias with cement, with the control side contained in the membrane pouch. Bone blood perfusion was measured by microsphere technic, and bone remodeling by 99mTc-methylene diphosphonate uptake and by histologic technique. In bone exposed to the combination of polymerization heat and monomer, both perfusion and remodeling were impaired. We did not find any effects of polymerization heat alone.

We conclude that hot toxic chemicals from bone cement during polymerization may inhibit bone blood perfusion and remodeling, whereas heat alone seems to be of minor importance for the regenerative processes in cemented diaphyseal bone.  相似文献   
68.
The safety of awake tracheal intubation in cervical spine injury   总被引:4,自引:0,他引:4  
As a referral centre for cervical spine injuries, we have routinely performed awake tracheal intubation when intubation was indicated. A retrospective case control study was undertaken to review the frequency of neurological deterioration and aspiration associated with our approach. Neurological deterioration was assessed by a change in level of injury or neurological grade at admission and discharge. Four hundred and fifty-four patients with critical cervical spine and/or cord injuries were reviewed over an eight-year period. A case group of 165 patients underwent tracheal intubation awake within two months of injury. A control group of 289 remained unintubated during the same period. A comparison of spinal neurological status between admission and discharge revealed no statistically significant difference in neurological deterioration between the two groups. This occurred despite a greater injury severity score in the case group. No evidence of aspiration during intubation was documented. We conclude that awake tracheal intubation is a safe method of airway management in patients with cervical spine injuries.  相似文献   
69.
The purpose of this study was to examine the structural requirements of polychlorinated and polybrominated biphenyls (PCBs and PBBs) for altering tissue levels of retinoids. Seven congeneric PCBs and PBBs were studied: 3,3',4,4'-tetrachlorobiphenyl (TCB), 2',3,3',4,5- and 3,3',4,4',5-pentachlorobiphenyls (-PeCBs), 3,3',4,4'- and 3,3',5,5'-tetrabromobiphenyls (-TBBs), 2,2',3,3',5,5'-hexachlorobiphenyl (-HCB), and 3,3',4,4',5,5'-hexabromobiphenyl (-HBB). Male Sprague-Dawley rats were fed a vitamin A-adequate diet (1.3 mg/kg) for 30 days before being given a single IP injection of one of seven polyhalogenated biphenyls (150 mumol/kg) in corn oil (10 ml/kg) or vehicle alone. Rats were killed 1 week later. Except for 3,3',4,4',5,5'-HBB, all PCBs and PBBs studied significantly decreased serum retinol levels and, except for 3,3',4,4',5,5'-HBB and 2,2',3,3',5,5'-HCB, all PCBs and PBBs also lowered the serum retinol-binding-protein (RBP) content. The activity of hepatic retinyl ester hydrolase (REH) was reduced by the treatment of 3,3',4,4',5-PeCB, 3,3',4,4'-TBB, and 3,3',4,4',5,5'-HBB. The levels of hepatic retinol were decreased by 2,2',3,3',5,5'-HCB, 2',3,3',4,5-PeCB, and 3,3',4,4',5-PeCB, while levels of hepatic retinyl palmitate were decreased by 2',3,3',4,5-PeCB, 3,3',4,4',5-PeCB, 3,3',4,4'-TCB, 3,3',4,4'-TBB, and 3,3',4,4',5,5'-HBB. The substantial decreases in hepatic retinyl palmitate levels could not be explained solely on the basis of hepatomegaly caused by acutely toxic PCBs and PBBs. All halogenated biphenyls which caused a decrease in hepatic retinyl palmitate also caused an increase in renal retinyl palmitate except 3,3',4,4',5-PeCB. In summary, the acutely toxic (nonortho substituted) congeners had pronounced effects on hepatic, renal, and serum retinoids whereas other biphenyls only decreased serum retinol levels. The effects of these seven compounds on REH activity were not correlated with the effects on serum retinol or RBP levels. Therefore, this study shows that the structure-activity relationships for altering hepatic retinoids differ from those for serum retinol, implying the involvement of multiple mechanisms.  相似文献   
70.
Zusammenfassung Grundlagen: Die operative Therapie gro?er Zysten am Unterkiefer wirft hinsichtlich des chirurgischen Vorgehens verschiedene Probleme auf. Ohne begleitende Ma?nahmen erfordern gro?e Zysten h?ufig eine Zystostomie, die mit einer ausgedehnten Nachbenhandlungsphase und einem zum Teil erheblichen Knochensubstanzverlust verbunden ist. Methodik: Ein operatives Vorgehen unter Verwendung eines tempor?r entfernten freien Kortikalisdeckels wird vorgestellt, das die M?glichkeit er?ffnet, auch gro?e Zysten im Sinne einer Zystektomie zu entfernen. Ergebnisse: Die Anwendung und der Verlauf bei 16 Patienten werden retrospektiv dargelegt. Wesentliche Komplikationen im Sinne von Wundheilungsst?rungen traten bei 3 Patienten auf. Schlu?folgerungen: Bei ausgedehnten Zysten des Unterkiefers stellt die beschriebene Methode eine Alternative zu den sonst üblichen Verfahren dar, um dem Patienten sowohl die Nachteile der Zystostomie als auch den Mehraufwand einer Knochentransplantation zu ersparen.   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