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   677篇
  免费   35篇
  国内免费   12篇
耳鼻咽喉   2篇
儿科学   11篇
妇产科学   35篇
基础医学   68篇
口腔科学   10篇
临床医学   73篇
内科学   123篇
皮肤病学   5篇
神经病学   23篇
特种医学   47篇
外科学   134篇
综合类   67篇
预防医学   36篇
眼科学   7篇
药学   49篇
中国医学   1篇
肿瘤学   33篇
  2022年   9篇
  2021年   8篇
  2020年   7篇
  2018年   13篇
  2017年   14篇
  2016年   11篇
  2015年   23篇
  2014年   23篇
  2013年   27篇
  2012年   30篇
  2011年   30篇
  2010年   17篇
  2009年   24篇
  2008年   21篇
  2007年   40篇
  2006年   23篇
  2005年   20篇
  2004年   33篇
  2003年   12篇
  2002年   9篇
  2001年   8篇
  2000年   10篇
  1999年   17篇
  1998年   16篇
  1997年   22篇
  1996年   11篇
  1995年   8篇
  1994年   8篇
  1993年   8篇
  1992年   12篇
  1991年   18篇
  1990年   27篇
  1989年   22篇
  1988年   17篇
  1987年   20篇
  1986年   12篇
  1985年   15篇
  1984年   8篇
  1983年   14篇
  1982年   9篇
  1981年   4篇
  1980年   3篇
  1979年   3篇
  1978年   3篇
  1977年   3篇
  1975年   2篇
  1971年   3篇
  1958年   11篇
  1957年   5篇
  1952年   2篇
排序方式: 共有724条查询结果,搜索用时 22 毫秒
51.
STUDY OBJECTIVE: To determine the usefulness of the left upper quadrant approach in gynecologic laparoscopic surgery. DESIGN: Retrospective study (Canadian Task Force classification II-2). SETTING: University referral center. PATIENTS: Twenty-four women with longitudinal scars from previous laparotomy through or close to the umbilicus. INTERVENTION: Left upper quadrant was chosen as the site of primary entry of the reusable Veress needle (ninth or tenth left intercostal space) and reusable primary cannula (left upper quadrant just below the left subcostal margin). MEASUREMENTS AND MAIN RESULTS: Intraabdominal adhesions between old longitudinal scars and underlying bowel or omentum were present in 14 patients. Adhesions involving omentum only were present in 10 patients, bowel only in 2, and both omentum and bowel in 2. The only intraoperative complication was emphysema in one woman. All operative procedures were completed laparoscopically. CONCLUSION: The left upper quadrant approach is a safe entry point for reusable instruments at laparoscopic surgery in patients with midline incisions close to the umbilicus.  相似文献   
52.
AIMS: Children with treatable, vision impairing conditions may not have access to surgical care when they live in regions where anaesthesia is unavailable. The use of ketamine anaesthesia in a developing region was studied to determine its safety and effectiveness. METHODS: This is a consecutive series of 679 children who had a variety of paediatric eye disorders necessitating a short general anaesthesia. Ketamine was administered intravenously by a paediatrician with training in paediatric resuscitation procedures. Both intraocular and extraocular procedures were performed. The location of treatment was the Tilganga Eye Hospital in Kathmandu, Nepal, a developing region of the world. The study took place over a 5 year period. RESULTS: All procedures were performed without any anaesthetic complications. No child required unanticipated resuscitation or laryngeal intubation. Postoperative dysphoria occurred occasionally and was difficult to measure quantitatively. This side effect of ketamine resolved by the first postoperative day. CONCLUSION: Ketamine is an effective agent for both intraocular and extraocular surgery in the paediatric age group. None of the children in this series needed resuscitation or intubations, and the ophthalmic surgery was carried out safely. Ketamine can be used safely in any ophthalmic procedure of short duration by a person having some training in anaesthetic resuscitation procedures. Because of its simplicity and safety, ketamine may be useful in a simple ophthalmic setup in the developing word.  相似文献   
53.
OBJECTIVE: The administration of amino acid (AA) mixtures that are selectively deficient either in tryptophan or phenylalanine plus tyrosine can decrease serotonin or catecholamine synthesis, respectively. In the present study, we assessed whether a mixture that was simultaneously deficient in tryptophan, phenylalanine and tyrosine could induce sufficient protein synthesis that plasma levels of all 3 monoamine precursors would decrease. DESIGN: Ten healthy volunteers (5 male, 5 female) were administered a tryptophan/phenylalanine/tyrosine-deficient AA mixture in an open-label study. Plasma concentrations of large neutral AAs were measured before and 5 hours after mixture ingestion. RESULTS: The tryptophan/phenylalanine/tyrosine-deficient mixture lowered plasma concentrations of the 3 AAs by 67;, 78% and 77%, respectively (p < or = 0.001); their ratio to other large neutral AAs was decreased more, namely, by 87%, 90% and 90% (p < or = 0.001). Mood lowering was seen on 3 subscales of the bipolar Profile of Mood States, that is, elated-depressed, composed-anxious and clearheaded-confused, as well as 2 visual analog scales, bored and irritated (p < or = 0.05). CONCLUSIONS: Acute tryptophan/phenylalanine/tyrosine depletion may be a suitable new method for rapidly decreasing serotonin and catecholamine transmission simultaneously.  相似文献   
54.
The current mechanism for monitoring toxicity symptoms in cancer trials depends on a complex paper-based process. Electronic collection of patient-reported outcomes (PROs) may be more efficient and accurate. An online PRO platform was created including a simple data entry interface, real-time report generation, and an alert system to e-mail clinicians when patients self-report serious toxicities. Feasibility assessment involving 180 chemotherapy patients demonstrated high levels of use at up to 40 follow-up clinic visits per patient over 16 months (85% of patients at any given visit), with high levels of patient and clinician acceptance and satisfaction (>95%). Alerts were used as the basis for delayed chemotherapy treatments, dose modifications, and scheduling changes. These results demonstrate that online patient-reporting is a feasible strategy for chemotherapy toxicity symptom monitoring, and may improve safety and satisfaction with care. Ongoing multi-center research will evaluate the impact of this approach on clinical and administrative outcomes.  相似文献   
55.
Background: Thirty six cases of lenticular nucleus drop following phacoemulsification and 43 cases of posterior dislocation of intraocular lens (IOL) inclusive of two paediatric cases were managed by a modified vitrectomy procedure without using perfluorocarbon liquid (PFCL).  相似文献   
56.
本文报告了用电化学检测器的高效液相色谱法测定血清及尿中速尿含量的方法。样品予处理方法:血清用乙腈除蛋白,尿用蒸馏水稀释50倍。采用作者合成的FD-Val-OH作为内标物。色谱条件为:反相柱,以含35%乙醇的5mmol/L四丁基铵水溶液为流动相(pH7.50),流速1.0ml/min;用电化学检测器,检测电压0.90V:速尿及内标物的保留时间分别为10和15min。通过计算速尿对内标物的峰高比求得速尿含量。血清及尿中的最低检测浓度分别为16和9ng/ml。标准曲线在0.25~5ng/μl(血清)、0.5~10ng/μl(尿)的浓度范围内呈线性关系。血清及尿中回收率分别为100.5%和100.6%。变异系数在4.6%以下。  相似文献   
57.
58.
Rothko  K; Kickler  TS; Clay  ME; Johnson  RJ; Stroncek  DF 《Blood》1989,74(5):1698-1703
We characterized neutrophil autoantigens using an immunoblotting technique with antibodies obtained from patients with autoimmune neutropenia. These results were correlated with serologic characterization of the antibodies, using indirect immunofluorescence and leukoagglutination. Of the 17 sera immunoblotted, 16 showed discrete bands in the molecular weight range of 30 to 112. Three patients with Felty's syndrome reacted with an antigenic target of 80 to 84 Kd molecular mass, a finding not seen in any of the other patients studied. By serologic testing, none of the autoimmune sera showed serologic specificity for any known neutrophil-specific alloantigen. Using an anti-NA-1 serum, we identified antigenic targets at 40, 50, and 101 Kd in both NA-1-positive and NA-1-negative neutrophils. Ten of 17 autoimmune sera showed reactivity in this corresponding range. These studies demonstrate that immunoblotting may be used to identify antigenic targets in autoimmune neutropenia and may suggest a specificity of these antibodies not definable by serologic techniques. Correlation of immunoblot reactivity with disease states associated with immune neutropenia may be useful in the study of the pathogenesis of the different forms of autoimmune neutropenia.  相似文献   
59.
60.
P T Daniel  K T Pun  S Ritschel  I Sturm  J Holler  B D?rken  R Brown 《Blood》1999,94(3):1100-1107
Members of the Bcl-2 gene family have been implicated in the regulation of cell death induced by cytostatic drugs. In some malignancies such as B-cell lymphoma, there is evidence that high expression of Bcl-2 is an independent negative prognostic marker and the overexpression of Bcl-2 has been shown to confer resistance to cytotoxic drugs by preventing drug-induced apoptosis. This function of Bcl-2 can be antagonized by apoptosis-promoting members of the Bcl-2 family. We previously showed that overexpression of Bax restores the chemosensitivity of Bax-deficient breast cancer cell lines. Therefore, we investigated whether the death-promoting Bcl-2 homologue Bik/Nbk can enhance cytostatic drug-induced apoptosis. As a model, we used the T-cell leukemia H9 (CD3(+) and CD4(+)CD8(-)), which is resistant to corticosteroid-induced cell death and does not express endogenous Bik/Nbk. Sensitivity for drug-induced apoptosis was increased 10- to 39-fold in cells transfected with the full-length coding sequence of Bik/Nbk. In addition, apoptosis induced via CD95/Fas or heat shock was increased to a similar extent. These data show that Bik/Nbk, which, unlike Bax, carries only a BH3 but no BH1 or BH2 domain may be a target to enhance chemosensitivity. The complete suppression of tumor growth in a severe combined immunodeficient mouse xenotransplant model suggests that, in analogy to Bax, Bik/Nbk may function as a tumor suppressor gene.  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