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   147038篇
  免费   14166篇
  国内免费   11135篇
耳鼻咽喉   1245篇
儿科学   1554篇
妇产科学   1506篇
基础医学   17139篇
口腔科学   2625篇
临床医学   19713篇
内科学   21620篇
皮肤病学   1518篇
神经病学   7390篇
特种医学   5322篇
外国民族医学   93篇
外科学   15066篇
综合类   26273篇
现状与发展   45篇
一般理论   8篇
预防医学   9932篇
眼科学   4239篇
药学   15780篇
  113篇
中国医学   9062篇
肿瘤学   12096篇
  2024年   453篇
  2023年   2251篇
  2022年   5385篇
  2021年   7962篇
  2020年   5970篇
  2019年   5037篇
  2018年   5269篇
  2017年   4813篇
  2016年   4541篇
  2015年   6924篇
  2014年   8541篇
  2013年   7640篇
  2012年   10992篇
  2011年   11996篇
  2010年   7757篇
  2009年   6146篇
  2008年   7836篇
  2007年   7714篇
  2006年   7453篇
  2005年   7174篇
  2004年   4832篇
  2003年   4386篇
  2002年   3765篇
  2001年   3304篇
  2000年   3408篇
  1999年   3580篇
  1998年   2389篇
  1997年   2383篇
  1996年   1880篇
  1995年   1783篇
  1994年   1553篇
  1993年   953篇
  1992年   1185篇
  1991年   947篇
  1990年   779篇
  1989年   727篇
  1988年   628篇
  1987年   555篇
  1986年   486篇
  1985年   363篇
  1984年   163篇
  1983年   138篇
  1982年   79篇
  1981年   88篇
  1980年   54篇
  1979年   64篇
  1978年   2篇
  1963年   1篇
  1962年   1篇
  1961年   1篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
171.
目的探讨研究生的主观幸福感与人格的关系。方法采用艾森克人格问卷量表与总体主观幸福感量表(GWB)对200名研究生进行测验。结果(1)在专业、性别、年级、年龄、婚姻状况上及来源上,研究生的主观幸福感不存在显著差异。(2)相关分析表明外向性人格纬度与总体幸福感存在显著的正相关,神经质与总体幸福感存在显著的负相关。稳定外向型和稳定内向型人格的总体幸福感水平最高,其次是不稳定外向型人格,总体幸福感水平最低的是不稳定内向型人格。结论外向性与神经质等人格特征是影响研究生幸福感的重要因素。  相似文献   
172.
《麦克白》在现代莎评中自身几乎转换成了充满原型的心理悲剧,它在女巫、鬼魂、超自然因素及阴暗的色彩等笼罩下充分展示悲剧主人公的潜意识心理及其极力保持心灵内外对统一的平衡的努力;主人公本我狂野的欲望及其在事后的病态心理表现正是他们意识内外失控的心态,犹如进入黑夜的漫长旅程。  相似文献   
173.
Two cancer cell growth inhibitory esters, 1,2-dipalmitoyl-3-glucosyl glycerol (1) and 1,6-dihydroxy-hexane-bis-palmitoyl ester (2), together with arachidic acid-2-hydroxy-glycerol ester, daucosterol, and oleanolic acid, were isolated from the roots of Peucedanum ledebourielloides (Apiaceae family). The structures were determined by spectroscopic analyses. The esters 1 and 2 displayed significant activity against the SGC-7901, HT-29, and HL-60 cancer cell lines.  相似文献   
174.
高业霞  Xu Donghong  刘一鸣 《护理研究》2008,22(22):2024-2025
[目的]探讨颅脑损伤病人应用亚低温治疗仪时具体间隔多长时间翻身不发生压疮.[方法]随机选择45例颅脑损伤应用亚低温治疗的病人,采取3 h后开始翻身,侧卧位时每次均为1 h,以后平卧位时间每次逐渐递增1/2 h.[结果]在应用亚低温治疗期间除3例病人在不同时段内发生轻微紫色冻伤外,所有病例均未发生压疮,平均翻身间隔时间为11.31 h,应用单样本统计学处理,有统计学意义(t=8.867,P<0.005).[结论]颅脑损伤病人在使用亚低温治疗过程中翻身间隔时间可以延长至8 h不发生压疮.  相似文献   
175.
目的 对比分析食管癌病例组与对照组血缘亲属食管癌患病风险,并了解食管癌家族中危险亲属人群患病的新线索.方法 采用病例对照研究方法 ,对食管癌病例组及对照组各720例进行逐层分析,以比较两组各血缘亲属父系、母系食管癌患病危险度(OR)的大小及差异.结果 (1)病例组Ⅰ级亲属食管癌患病危险度(1.34%~2.24%)显著高于对照组(0.78%~1.21%)(P<0.01);Ⅰ级亲属中病例组父母亲食管癌患病危险度为6.11%,显著高于对照组父母亲食管癌患病危险度2.97%(P<0O01).(2)以血缘亲属中父系和母系亲属逐层分析可见,病例组父系食管癌患病危险度(0.87%~1.01%)与母系患病危险度(0.50%~0.79%)均显著高于对照组父系食管癌患病危险度(0.53%~0.65%)与母系患病危险度(0.38%~0.47%)(P<0.05).进一步分析显示,病例组父系中男性亲属与母系中女性亲属,即父系中祖父、父亲、叔伯食管癌患病危险度为2.68%与母系中外祖母、母亲、姨的食管癌患病危险度1.91%均显著高于对照组父系中男性亲属食管癌患病危险度1.50%与母系中女性亲属食管癌患病危险度0.92%(P<0.01).结论 山西省食管癌患者血缘亲属发病危险主要是父亲及其兄弟、母亲及其姐妹,其下代患食管癌风险要大.  相似文献   
176.
Summary We prospectively examined bone growth patterns in 894 children aged 6–17 years at the baseline visit, with a 6-year follow-up. Results show bone “tracking” over a six-year interval and sexual dimorphism of bone attained levels and timing of peak bone growth. Our findings underscore childhood and adolescence as critical periods for building bone and developing gender differences. Introduction Bone growth patterns were prospectively examined in 894 Chinese children (496 males), aged 6–17 yrs, from a population-based twin cohort. Whole-body bone area (BA), bone mineral content (BMC), and bone mineral density (BMD) were measured by DEXA at baseline and a 6-yr follow-up. Methods Graphic smoothing plots and generalized estimating equations were used to model bone attained levels, growth, and “tracking”. Results Attained levels of BMC and BA increased curvilinearly with age. Male attained levels were higher than females after age ∼15 yr, but BMD was lower between 13–17 yrs (Tanner stage I to IV). In both genders, peak BMC and BMD growth lagged ∼2 yrs behind peak BA growth, which lagged 2 yrs behind peak height growth. Peak bone growth occurred 1–3 yrs later in males. Over the 6-yr follow-up, all bone measurements “tracked”, but “shifting” across ranks also occurred, and baseline tertile ranking influenced bone growth. Females with early menarche had higher attained levels than females with late menarche at age 12–13 yrs. Conclusion Our findings confirm and expand previous studies on peak bone growth conducted in Caucasian cohorts, particularly sexually dimorphic and maturational effects. The significant “tracking” of bone measurements in this 6-yr follow-up study underscores the importance that osteoporosis prevention should begin in childhood and adolescence. Fengxiu Ouyang and Binyan Wang contributed equally to this article. Source(s) of support: This study is supported in part by grant R01 HD049059, R01 HL0864619 and R01 AR045651 from the National Institute of Health and by the Food Allergy Project.  相似文献   
177.
腮腺良性和恶性多形性腺瘤的超声研究   总被引:1,自引:0,他引:1  
目的研究腮腺良性和恶性多形性腺瘤的超声特点,为临床医师诊治提供有效依据。方法选取腮腺良性多形性腺瘤患者79例和恶性多形性腺瘤患者15例,对其肿块的大小、硬度、内部回声、彩色多普勒血流显像(CDFI)特点结合病理学诊断进行对照研究。结果恶性多形性腺瘤的声像图特点与良性多形性腺瘤相似,但其肿瘤相对较大,质地更硬,内部回声分布更紊乱。不同性质的肿瘤的大小和质地有显著性差异,(P<0.01)。结论多形性腺瘤的超声诊断主要依据二维图像之特点。当多形性腺瘤大于3.0 cm,硬度较硬,内部回声分布不均多提示恶性。  相似文献   
178.
兔骨髓间充质干细胞Ⅱ型胶原表达的实验研究   总被引:1,自引:1,他引:0  
目的探讨兔骨髓间充质干细胞表达Ⅱ型胶原的实验研究方法。方法利用β1转化生长因子腺病毒表达载体(Ad—TGFβ1)转染兔骨髓间充质干细胞(MSCs),观察转染后的Ⅱ型胶原表达。结果细胞转染后Ⅱ型胶原在免疫印记和免疫组化检测下均呈强阳性表达。结论Ad—TGFβI转染兔骨髓MSCs可使其细胞内Ⅱ型胶原表达阳性。  相似文献   
179.
This study evaluated the safety and efficacy of batroxobin in treating hyperfibrinogenemia for secondary stroke prevention. Patients with ischemic stroke or transient ischemic attack (TIA) were measured for plasma fibrinogen levels. Selected participants had concomitant hyperfibrinogenemia (plasma fibrinogen > or = 3.0 g/l). Patients enrolled between 1 July 2003 and 31 December 2004 were treated with batroxobin; patients enrolled between 1 January 2002 and 30 June 2003 were treated without batroxobin. Batroxobin was administered intermittently via intravenous injection at 3-monthly intervals. Patients in both groups were followed for 1 year. Any cerebrovascular events and suspected adverse events were recorded. In total, 112 ischemic stroke/TIA patients with concomitant hyperfibrinogenemia were enrolled, 52 being treated with batroxobin and 60 without batroxobin. Six patients (11.5%) with batroxobin and 16 patients (26.7%) without batroxobin had recurrent cerebral ischemic events during follow-up. Stroke/TIA recurrence in patients without batroxobin was higher than that in patients with batroxobin (P < 0.05). Two patients with batroxobin and two patients without batroxobin developed hemorrhagic stroke during follow-up. There were five deaths (9.6%) in the batroxobin group, and seven deaths (11.7%) in the nonbatroxobin group during follow-up (P > 0.05). Intermittent intravenous injection of batroxobin can efficiently reduce the risk for stroke/TIA recurrence in patients with concomitant hyperfibrinogenemia.  相似文献   
180.
OBJECTIVES: We investigated whether the Na+-H+ exchange inhibitor, HOE642 (Hoe), and/or the Na channel blocker, mexiletine (Mex), enhance a cardioprotective effect on St. Thomas' Hospital cardioplegic solution (STS) to clarify the mechanism by which intracellular Na+ is accumulated after cardioplegic arrest. MATERIALS AND METHODS: Isolated working rat hearts were perfused with Krebs-Henseleit bicarbonate buffer (KHBB). The hearts were then arrested with STS and subjected to normothermic global ischemia (30 min). This was followed by Langendorff reperfusion (15 min) and then a working reperfusion (20 min). In study A, we added Hoe (5, 10, and 20 microM), Mex (70 microM), or a combination of Hoe (20 microM) and Mex (70 microM), to STS. In study B, we added Hoe (20 microM), Mex (70 microM), or a combination of Hoe (20 microM) and Mex (70 microM) to KHBB during the first 3 min of Langendorff reperfusion. RESULTS: In study A, the addition of Hoe (10 and 20 microM) to STS showed a significantly greater postischemic recovery of cardiac output compared to the control group [63.1+/-5.7% (10 microM), 62.7+/-4.7% (20 microM), and 55.5+/-4.6% (control), respectively]. The postischemic recovery of cardiac output was significantly greater in the group of the combined addition (Hoe and Mex) to STS than that in the control, 20 microM Hoe, 70 microM Mex groups [70.3+/-3.7 (Hoe and Mex), 55.5+/-4.6% (control), 62.7+/-4.7% (Hoe 20 microM), and 60.2+/-4.7% (Mex 70 microM), respectively]. The myocardial water content in the postischemic period was 565.1+/-29.1, 525.8+/-2.9, 509.4+/-19.6, and 532.2+/-20.1; it was 497.3+/-9.1 mL/100 g dry weight in the control; and 10 microM Hoe, 20 microM Hoe, and 70 microM Mex in the combined use groups. In study B, there was no significant difference in the postischemic recovery of cardiac output in all experimental groups. CONCLUSION: The combined use of the Na+-H+ exchange inhibitor and Na+ channel blocker during cardioplegia may achieve a superior cardioprotective effect on myocardial damage because of ischemia and reperfusion.  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