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   13439篇
  免费   1855篇
  国内免费   216篇
耳鼻咽喉   45篇
儿科学   238篇
妇产科学   185篇
基础医学   1220篇
口腔科学   153篇
临床医学   2440篇
内科学   1283篇
皮肤病学   82篇
神经病学   590篇
特种医学   461篇
外科学   876篇
综合类   2482篇
现状与发展   1篇
一般理论   5篇
预防医学   1180篇
眼科学   112篇
药学   1386篇
  16篇
中国医学   2546篇
肿瘤学   209篇
  2024年   57篇
  2023年   315篇
  2022年   413篇
  2021年   749篇
  2020年   876篇
  2019年   741篇
  2018年   503篇
  2017年   602篇
  2016年   549篇
  2015年   534篇
  2014年   976篇
  2013年   1057篇
  2012年   869篇
  2011年   995篇
  2010年   776篇
  2009年   634篇
  2008年   553篇
  2007年   504篇
  2006年   395篇
  2005年   359篇
  2004年   303篇
  2003年   272篇
  2002年   230篇
  2001年   220篇
  2000年   173篇
  1999年   147篇
  1998年   149篇
  1997年   135篇
  1996年   114篇
  1995年   103篇
  1994年   93篇
  1993年   95篇
  1992年   106篇
  1991年   75篇
  1990年   73篇
  1989年   86篇
  1988年   70篇
  1987年   62篇
  1986年   54篇
  1985年   71篇
  1984年   82篇
  1983年   45篇
  1982年   62篇
  1981年   49篇
  1980年   31篇
  1979年   21篇
  1978年   18篇
  1977年   14篇
  1976年   21篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 228 毫秒
51.
目的比较血浆置换(PE)与大剂量甲泼尼龙治疗蜂螫伤致溶血性贫血的疗效。方法蜂螫伤导致溶血性贫血患者35例,入院后除常规的对症处理外,拒绝行PE治疗的患者分为大剂量甲泼尼龙治疗组(n=13),其余的22位患者采用PE方法治疗,比较两组的溶血控制时间、并发症发生率、死亡率、平均住院天数。结果与大剂量甲泼尼龙治疗组相比,PE治疗组溶血控制的时间相当,差异没有统计学意义,但该组患者的并发症发生率、死亡率、平均住院天数均低于前者,差异有统计学意义(P0.05)。结论 PE治疗能够有效治疗蜂螫伤所致溶血性贫血,且降低并发症的发生率,从而减低死亡率,缩短病程,减少平均住院天数,是早期治疗蜂螫伤中毒的有效手段。  相似文献   
52.
Abstract: Prevention of hyperacute rejection is a difficult and unsolved problem in xenotransplantation. Natural antibodies and complement activation have been known to play an important role in the xenotransplantation between discordant species pairs. In the present study, total blood exchange (TBE) was performed with pyridox-alated-hemoglobin-polyoxyethylene conjugate (PHP) solution (Ajinomoto Co., Inc., Kawasaki, Japan) before cardiac xenotransplantation in order to remove the immunoglobulins and prolong xenograft survival time. Guinea pigs and rats were used as the discordant species combination for donor and recipient. Two groups were established: Group 1, untreated control (n = 8) and Group 2, TBT with PHP solution (n = 8). The exchange blood transfusion was carried out at the rate of 15–20 ml/h utilizing PHP solution using a blood pump. After the blood exchange was processed, hematocrit (Ht) levels dropped to 4 or 5%, and a cardiac xenotransplantation was performed within 24 h. The levels of serum IgA, IgM, and IgG were decreased to less than 25, 25, and 10% of the base line, respectively, after blood exchange. A mean xenograft survival time in Group 2 was prolonged to 472 ± 74 min and to 10.4 ± 1.8 min in Group 1 (p < 0.01). A titer of the anti-guinea pig lymphocytotoxic antibody in rat serum was decreased to almost nil. The data from this study suggest that total blood exchange with PHP solution may be useful in preoperative removal of xenograft antibodies in xenotransplantation.  相似文献   
53.
Australian nursing has undergone rapid academization in the past 10 years and this radical change has tended to meld the somewhat different academic traditions of North America and Britain. The introduction of doctoral education in nursing in 1987 has led to a massive increase in scholarly activity and to the preparation of talented leaders. We concur with the view expressed by Henry (1997), "I am convinced that the problems we face in the nursing services would be much more creatively solved if the majority of our doctoral programs prepared young, energetic nurses, early in their career, for clinical practice, not for research and teaching" (p. 162).  相似文献   
54.
. We have estimated sarcoplasmic reticulum calcium content using rapid application of caffeine on voltage clamped, isolated guinea-pig ventricular myocytes. Caffeine induces the release of calcium from the sarcoplasmic reticulum and this calcium is extruded from the cells by the sarcolemmal Na/Ca exchange. Integrating the inward Na/Ca exchange current thus allows estimations of sarcoplasmic reticulum calcium content. Ventricular myocytes were stimulated to reach new steady-states by action potential voltage clamps of varying duration. Once contractile steady-state had been reached caffeine was rapidly applied in place of the next action potential and sarcoplasmic reticulum calcium content measured. Prolonging the action potential duration increased sarcoplasmic reticulum calcium content and vice-versa. This calcium loading may underlie the positive inotropic effect of increased action potential duration. Received: 11 July 1996 / Received after revision: 15 October 1996 / Accepted: 26 November 1996  相似文献   
55.
熵代表无序的水平,作者使用通气的熵变(ECV)指示肺通气的不均匀性,ECV定义为当前泡潮气量趋近于零时每摩尔被吸入气体从不均匀通气到均匀通气的熵变的极限。本文从熵的基本公式民地出ECV的计算方程。用几个数学模型肺将ECV同其他7个洗出指标进行了比较。8个指标中,只有ECV仅取决于通气分布,其他7个指标不仅取决于通气分布,还同潮气量和死腔的大小有关。这影响了它们评价肺通气不均匀性的效果,ECV的另一  相似文献   
56.
目的:从牛脑中分离纯化酸性成纤维细胞生长因子(aFGF)并鉴定生物活性,方法:根据DenisGOSPODAROW-ICZ的方法,新鲜牛脑匀浆,三步硫酸铵盐析。最后沉淀物溶解透析后予离子交换层析及琼脂糖胶亲和层析,促3T3细胞DNA合成率鉴定生物活性。结果:用1.0mol/LNaCl的缓冲液洗脱得到分子量为13600的多肽,得率为610μg/kg牛脑,氨基酸组成分析与已知的aFGF相同,促3T3细胞DNA合成的最低浓度为0.5ng/ml,最大效应浓度50ng/ml,ED50值为8ng/ml。结论:aFGF具有强烈的促细胞增殖作用。  相似文献   
57.
Credentialed Persons, Credentialed Knowledge   总被引:1,自引:0,他引:1  
The vast experimental literature on human error agrees with history of medicine, folklore, and superstition In discrediting knowledge claims based solely on anecdotal impressions. Since clinical experience consists of anecdotal impressions by practitioners, tt Is unavoidably a mixture of truths, half-truths, and falsehoods. The scientific method is the only known way to distinguish these, and it is both unscholariy and unethical for psychologists who deal with other persons' health, careers, money, freedom, and even life itself to pretend that clinical experience suffices and that quantitative research on diagnostic and therapeutic procedures is not needed. Disputes about philosophy of science (e.g., logical positivism) are irrelevant to this issue, which is simply one of distinguishing knowledge claims that bring reliable credentials and others that do not.  相似文献   
58.
目的探讨血浆置换(简称PE)床边治疗重型肝炎的临床疗效。方法60例病例采用常规内科治疗加PE治疗,比较PE治疗前后临床症状缓解时间及血生化变化。结果临床症状缓解迅速,黄疸减退,白蛋白、胆碱脂酶升高,PT恢复,补体上升,不影响肾功及电解质。结论PE为重型肝炎一种行之有效的治疗方法。  相似文献   
59.
福建产舟山眼镜蛇毒细胞毒素的快速分离纯化及鉴定   总被引:8,自引:4,他引:4  
目的 从舟山眼镜蛇毒中分离纯化细胞毒素(CTX),并鉴定其理化性质。方法 采用SP—Sephadex C-25阳离子交换色谱及Sephasil Peptide C18反相高效液相色谱法从舟山眼镜蛇毒中分离纯化CTX,SDS—PAGE(Tris—Tricine系统)鉴定纯度,Edman降解法测定N端氨基酸序列。结果 粗毒经阳离子交换色谱,得到14个蛋白峰,其中第X~XⅢ峰具CTX活性;再分别经反相色谱纯化,得到4个CTX.总得率为32.48%;SDS—PAGE显示为均一蛋白,分子量依次为:7.28,7.33,7.24和7.38kD;测定它们N端20个氨基酸序列。结论 采用阳离子交换和反相高效液相色谱可快速、高效地从眼镜蛇毒中获得4个CTX纯品。  相似文献   
60.
Summary Bronchus stump insufficiency following lung resection, with an average incidence of 4%, is a serious complication which carries a mortality of up to 90%. Operative transthoracic approaches have been largely unsatisfactory because of the high operative risk and rapidly spreading infection. In an experimental study on 18 pigs, endoscopic occlusion of infected bronchus stump fistulae was achieved with fibrin sealant (1 ml, 500 units/ml thrombin, 3500 units/ml aprotinin) applied via a flexible bronchoscope. During autopsy, all bronchus stump fistulae were found to have healed after the second postoperative week. Transitory local abscesses of the pleura could be prevented by high-dose systemic antibiotic therapy for 5 postoperative days but not by antibiotics added to the fibrin sealant. This endoscopic method has already been performed successfully in 3 clinical cases; additional sclerotherapy with (2–3 ml Ethoxysclerol applied around the fistula orifice was carried out before fibrin sealing to stimulate fibrosis. Endoscopic controls demonstrated fistula closure by granulation tissue after 2 weeks. This procedure could become the method of choice for infected postoperative fistulae of the bronchus stump and should be attempted in any case before operative approaches are considered.  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