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   60562篇
  免费   4968篇
  国内免费   3959篇
耳鼻咽喉   595篇
儿科学   818篇
妇产科学   625篇
基础医学   5971篇
口腔科学   854篇
临床医学   8002篇
内科学   7675篇
皮肤病学   649篇
神经病学   2746篇
特种医学   2246篇
外国民族医学   28篇
外科学   5118篇
综合类   12743篇
现状与发展   12篇
一般理论   4篇
预防医学   5031篇
眼科学   1599篇
药学   6944篇
  74篇
中国医学   3576篇
肿瘤学   4179篇
  2024年   110篇
  2023年   586篇
  2022年   1713篇
  2021年   2370篇
  2020年   1910篇
  2019年   1608篇
  2018年   1647篇
  2017年   1802篇
  2016年   1536篇
  2015年   2563篇
  2014年   3406篇
  2013年   3391篇
  2012年   4953篇
  2011年   5573篇
  2010年   4141篇
  2009年   3462篇
  2008年   4191篇
  2007年   3778篇
  2006年   3696篇
  2005年   3150篇
  2004年   2397篇
  2003年   2220篇
  2002年   1862篇
  2001年   1427篇
  2000年   1212篇
  1999年   961篇
  1998年   593篇
  1997年   585篇
  1996年   477篇
  1995年   402篇
  1994年   386篇
  1993年   221篇
  1992年   229篇
  1991年   178篇
  1990年   143篇
  1989年   107篇
  1988年   99篇
  1987年   92篇
  1986年   61篇
  1985年   60篇
  1984年   49篇
  1983年   31篇
  1982年   13篇
  1981年   7篇
  1980年   8篇
  1978年   7篇
  1975年   8篇
  1974年   7篇
  1973年   10篇
  1968年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
The regulation of interleukin 6 (IL-6) expression in the B-lymphocyte-supporting murine stromal cell line BMS2 has been examined in response to exogenous cytokines and chemical agents. Kinetic analyses of IL-6 mRNA induction and decay are presented together with analysis of the IL-6 biological activity. The cytokines tumor necrosis factor, interleukin 1 (alpha and beta), and transforming growth factor beta, as well as forskolin and dibutyryl cyclic AMP, all induce a transient rise in the steady-state level of IL-6 mRNA and an increased release of IL-6 protein. To study its regulation at the chromatin level, the murine IL-6 genomic gene has been cloned. Induction of IL-6 expression correlates with increased DNA nicking, consistent with increased topoisomerase I and endogenous nuclease activity. This finding is supported by kinetic analyses using camptothecin, a topoisomerase I inhibitor. We conclude that IL-6 regulation in murine stromal cells capable of supporting B-lymphopoiesis is comparable to that observed in human diploid fibroblasts.  相似文献   
32.
老年病人上腹部手术后应用PCEA的临床效果观察   总被引:1,自引:1,他引:0  
目的 观察老年人上腹部术后病人自控硬膜外镇痛 (PCEA)的疗效及对内分泌功能的影响。方法 6 3例择期行胃癌根治术的老年患者 ,ASAⅠ -Ⅱ级 ,随机分为 3组 (每组 2 1例 ) :A组术后行硬膜外镇痛 (PCEA) ;B组术后行静脉镇痛 (PCIA) ;C组术后按需肌肉注射哌替啶镇痛 ;对比术后镇痛效果并分别于麻醉前 ,切皮后 90分钟 ,术后 6 0及 1、2、3天分别抽取外周静脉血测定血糖、胰岛素、皮质醇、肾上腺素浓度。结果 A、B组镇痛效果均满意 ,C组镇痛效果欠佳 ,综合镇痛质量A组优于B组优于C组 ;3组于切皮后 90分钟血皮质醇、血糖浓度均升高 ,但A组低于C、B两组 (P <0 .0 5 ) ,术后 6 0分钟均达高峰 (P <0 0 1) ,术后 2 4至 4 8小时虽有下降 ,但仍明显高于麻醉前水平 (P <0 0 5 ) ;血胰岛素水平 ,A、B组术后 3天无明显变化 ,C组术后第 1、2天升高显著 (P <0 .0 1及P <0 .0 5 ) ;肾上腺素A、B组术后无明显升高 ,C组术后 6 0分钟明显升高 ,于术后 3天仍未恢复至术前水平。结论 老年病人上腹部术后PCIA及PCEA均能达到优良的镇痛效果 ,PCEA能有效地抑制术后机体的应激反应 ,有利于术后病人的恢复。  相似文献   
33.
BACKGROUND: Chronic mucocutaneous candidiasis (CMC) is a rare disorder characterized by persistent or recurrent candidal infections of the skin, nails and mucous membranes or by a variable combination of endocrine failure as well as immunodeficiency. Oral clinicopathological features of CMC have seldom been described in detail. METHODS: Seven patients with CMC were reported in the study. The clinical and histological findings, etiological Candida species, immunological evaluation, and therapeutic pattern of oral lesions, were analyzed. RESULTS: Long-standing whitish hyperplastic and nodule-like lesions with exaggerated deep fissure were the typical and characteristic oral manifestations presented by all patients. The tongue was the most common site affected. Histologically, no obvious distinction was found between CMC and other forms of candidal infection. Abnormal proportions of T-lymphocyte subsets and positive titers of autoantibody were observed in three subjects (42.9%) and one patient (14.3%) respectively. Meanwhile, four subjects (57.1%) showed decreased albumin and increased globulin, three cases (42.9%) had high levels of ESR. But no iron deficiency was found. Candida albicans was the microorganism isolated from these patients. CONCLUSIONS: Multiple and widespread candidal infectious lesions can be observed on the oral cavity of CMC patients. Hyperplastic and nodule-like lesion with irremovable whitish patches and deep fissure are the most common oral manifestations of these patients. Dentists, otolaryngologists and pediatricians should be familiar with the clinical appearances of CMC to make an accurate diagnosis. Potential systemic disorders should be concerned to avoid the reoccurrence of oral candidiasis.  相似文献   
34.
停跳或不停跳心脏手术对血清 S-100B蛋白表达的影响   总被引:2,自引:1,他引:1  
【目的】研究心脏手术围术期血清S-100B蛋白表达及其与停跳或不停跳心肺转流方式和时间的关系。【方法】体外循环心脏手术患者23例,测转流前、转流10min、转流末、转流后24h的血清S-100B蛋白表达水平。【结果】①血清S-100B蛋白质量浓度在体外循环前后动态变化:转流前(M)为0.27μg/L,转流10min后升至0.57μg/L(P<0.01),转流末达峰值1.80μg/L(P<0.01),转流后24h降为0.22μg/L(P>0.05)。转流末的血清S-100B蛋白质量浓度与转流时间呈正相关(r=0.488,P<0.05)。②停跳组(n=6)转流前、转流10min、转流末、转流后24h平均血清S-100B蛋白质量浓度分别为(0.17±0.09)μg/L、(0.48±0.13)μg/L、(1.65±0.52)μg/L和(0.19±0.04)μg/L,不停跳组(n=6)分别为(0.26±0.14)μg/L、(0.71±0.41)μg/L、(1.59±0.84)μg/L和(0.23±0.11)μg/L,两组差别无统计学意义(P>0.05)。【结论】体外循环可导致血清S-100B蛋白表达增高,其表达水平与心肺转流时间呈正相关,但与停跳或不停跳转流方式无关。  相似文献   
35.
本文报告了我科1978~1990年间收治的降突性皮纤维肉瘤23例,均经组织学证实.治疗以手术切除为主,术后局部复发率为65.2%.无一例发生转移.切除不彻底是复发的主要原因.作者指出广泛切除是防止复发的主要措施,手术前后的放疗有可能减少复发.  相似文献   
36.
FOREWORDPeritonealdialysisrepresentssoluteandfluidexchangemainlybetweenperitonealcapillarybloodanddialysissolutionintheperitonealcavity'CombinedwithhemodialySisandrenaltransplantation,peritonealdialysisisusedmainlyforthetreatmentofrenalfailure,particularlyforchronicfailure'In1976,Prof'Popovichdevelopedcontinuousambulatoryperitonealdialysis(CAPD)basingontheconceptofcontinuousequilibrationdialysis('1'Fromthenon,peritonealdialysisfounditsclinicaluse'Continuouscyclicperitonealdialysis(CCPD…  相似文献   
37.
“C”型曲线的中耳声学特性改变与鼓室积液的关系   总被引:10,自引:2,他引:8  
对40耳声导抗检查为“C”型曲线患耳进行中耳系统共振频率点测试并进行鼓室穿刺抽液,结果表明:共振频率点低于600Hz,患耳鼓室积液阳性率为82.1%,高于600Hz患者鼓室和液阳性率16.7%,提示依据鼓室导抗图和共振频率点测定可初步判断“C”型曲线患耳鼓室积液的可能.  相似文献   
38.
J Q Wu  T Liu  Y L Bai 《中西医结合杂志》1989,9(3):141-3, 131
This apparatus is designed in accordance with the doctrine and principles of traditional Chinese medicine and based on the theory of meridian and specific massage procedure in conjunction with the "Information Theory" and electron utilizing technique. It utilizes a programmed induction "Special Wave" to stimulate a series of acupuncture points, combined with administration of western drugs from a regime of "General Attack" treatment on the gallbladder stones, to enhance their evacuation. By stimulating the specific acupuncture points with this apparatus through the action of "Special Wave" strong contraction of the gallbladder can be elicitated. Experiments on dogs showed that under such stimulation the intra-gallbladder pressure can be increased 26 times, producing a jet of bile flow which facilitates the expulsion and evacuation of stones in the gallbladder. Method of use: first place a conductive rubber pad on the acupuncture point to be stimulated, then use a hand-held electrode to massage-stimulate the meridian. It is carried out forward and backward along the direction of meridian. The whole procedure is carried out under direct visualization with the help of ultrasonic B-scan. When dilatation of the common bile duct is observed, the hand-help electrode is used to perform push-compress massage on the meridian, and acupuncture points making the stones enter the common bile duct B-scan give proper orientation for the manipulation. This method has been tested clinically on 410 patients with good results. The evacuation rate of the gallbladder stones was 92.7% with complete evacuation achieved in 17.3%.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
39.
Myocarditis and dilated cardiomyopathy (DCM) are common causes of morbidity and mortality in children and adults, most commonly due to infection with coxsackievirus B or adenovirus. Increased expression of the common human coxsackievirus B-adenovirus receptor (CAR) has been reported in patients with DCM. We investigated the CAR gene in patients with acquired or familial myocarditis/DCM for mutations/polymorphisms. Several polymorphisms or intronic substitutions, distant from the intron-exon boundaries, were identified but no mutations. Based upon these data it appears that CAR gene mutations are not a major host determinant in the development of myocarditis and DCM.  相似文献   
40.
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