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   14659篇
  免费   1081篇
  国内免费   245篇
耳鼻咽喉   175篇
儿科学   286篇
妇产科学   497篇
基础医学   1743篇
口腔科学   740篇
临床医学   1395篇
内科学   2823篇
皮肤病学   156篇
神经病学   1488篇
特种医学   510篇
外科学   1955篇
综合类   897篇
一般理论   1篇
预防医学   956篇
眼科学   424篇
药学   992篇
  4篇
中国医学   178篇
肿瘤学   765篇
  2023年   99篇
  2022年   125篇
  2021年   323篇
  2020年   223篇
  2019年   251篇
  2018年   296篇
  2017年   296篇
  2016年   289篇
  2015年   405篇
  2014年   410篇
  2013年   571篇
  2012年   690篇
  2011年   845篇
  2010年   615篇
  2009年   555篇
  2008年   709篇
  2007年   771篇
  2006年   709篇
  2005年   634篇
  2004年   613篇
  2003年   599篇
  2002年   574篇
  2001年   478篇
  2000年   446篇
  1999年   395篇
  1998年   195篇
  1997年   167篇
  1996年   135篇
  1995年   118篇
  1994年   138篇
  1993年   114篇
  1992年   236篇
  1991年   231篇
  1990年   200篇
  1989年   197篇
  1988年   194篇
  1987年   157篇
  1986年   162篇
  1985年   159篇
  1984年   109篇
  1983年   113篇
  1982年   71篇
  1980年   60篇
  1979年   87篇
  1978年   78篇
  1977年   69篇
  1975年   95篇
  1974年   71篇
  1973年   64篇
  1972年   68篇
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
31.
32.
Standard treatment for advanced rectal carcinoma currently includes surgery, radiotherapy, and chemotherapy. Although there are theoretic advantages to preoperative irradiation, it is often not performed because of the prolonged delay of surgery and the purported increase in perioperative complications. A pilot study was undertaken at our institution to evaluate a treatment protocol advocated by Dr. Papillon that offers a shorter treatment time and less patient morbidity than conventional preoperative therapy for rectal carcinoma. Twenty patients with rectal cancer underwent the preoperative regimen that consisted of 3,000 cGy delivered in 10 fractions over 12 days with concomitant 5-fluorouracil and mitomycin-C. Complications were acceptable. Local recurrence was lower than in most reported trials, and survival rates were comparable. Additional benefits of the protocol include lower radiation morbidity to the patient and a decreased delay between diagnosis and surgery.  相似文献   
33.
目的:探讨SPIR脂肪抑制技术在骨胳肌肉系统疾病MRI检查中的诊断价值。材料与方法:对36例骨、关节软组织疾病患者行T1W/SE、T2W/FSE及T2W/SPIR序列扫描,并对后两者进行比较。结果:各种病理性积液呈高信号;损伤性骨髓水肿呈高信号;骨折线呈低信号,如骨折断端出血则呈线状高信号;软组织肿瘤囊性部分呈高信号,实质部分呈中等强度信号;软组织炎症性病变为弥漫性高信号;骨病成骨性改变为低信号;骨髓病变为高信号或混杂等高信号;椎管内占位性病变及半月板损伤SPIR显示不清。结论:SPIR能提高正常组织与病变组织间的对比度,清晰地显示病变组织,作为T1W/SE、T2W/FSE序列的辅助检查,有助于提高骨胳肌肉系统疾病的诊断水平。  相似文献   
34.
BACKGROUND: Dyslipidaemia, inflammation and oxidative stress are prominent risk factors that potentially cause vascular disease in haemodialysis patients. Dialysis modalities affect uraemic dyslipidaemia, possibly by modifying oxidative stress, but the effects of dialyser flux and membrane material on atherogenic remnant particles and oxidized low-density lipoproteins (LDL) are unknown. METHODS: We performed a randomized crossover study in 36 patients on haemodialysis to analyse the effect of dialyser flux and membrane material on plasma lipids, apolipoproteins and markers of inflammation and oxidative stress. Stable patients on low-flux dialysis with polysulphone for >/=6 weeks were assigned to high-flux polysulphone or high-flux modified cellulose with similar dialyser surface area and permeability characteristics and crossed over twice every 6 weeks. RESULTS: Thirty patients completed the study per protocol. Treatments with high-flux polysulphone and modified cellulose lowered serum triglyceride (by 20% and 10%, respectively; P<0.05) and remnant-like particle cholesterol by 32% (P<0.001) and 11% (NS) after the first 6 weeks of treatment. Oxidized LDL decreased significantly with high-flux polysulphone, but not with modified cellulose. Apolipoproteins CII and CIII were reduced, whereas the ratio CII/CIII was increased (all P<0.05). Acute-phase proteins and LDL and high-density lipoprotein cholesterol remained unaffected. CONCLUSIONS: This randomized crossover study demonstrates a potent effect of high-flux haemodialysis on uraemic dyslipidaemia. Polysulphone membrane material showed superiority on oxidatively modified LDL, an indicator of oxidative stress in haemodialysis patients.  相似文献   
35.
OBJECTIVES: Persisting air leakage after pulmonary resection remains a significant problem. The aim of the study was to evaluate the incidence of air leakage after standard lobectomy and test the efficacy and safety of TachoComb (TC). METHODS: A total of 189 patients undergoing lobectomy were enrolled in a multi-centre, open, randomised, and prospective study to test the efficacy and safety of TachoComb (TC) for air leakage treatment. Air leakage was assessed by water submersion test, and scored as grades 0 if no, 1 if countable, 2 if a stream of and 3 if coalescent bubbles have been observed. Any sites with grade 3 air leakage received further stapling or limited suturing until grade 0, 1 or 2 was obtained. Treatment of air leakage was done with TC or suturing according to randomisation. Air leakage was assessed by further submersion tests. Postoperative air leakage was assessed using the Pleur-Evac system. RESULTS: Overall incidence of air leakage 48+/-6 h after surgery was 34% for TC and 37% for standard treatment (P=0.76). The reduction of intra-operative air leak intensity in the subgroup with grades 1-2 was significantly higher for the TC group (P=0.015). Postoperative air leakage intensity in the subgroup with air leakage grades 1-2 was lower for TC than standard treatment (P=0.047). The mean duration of postoperative air leakage in the subgroup with grades 1-2 was shorter for the TC group than for standard treatment, i.e. 1.9+/-1.4 vs. 2.7+/-2.2 days (P=0.015). CONCLUSIONS: TC could be proven as well-tolerated and safe. In the subgroup of patients with established air leakage, TC showed superior potential in reduction of intra-operative air leakage as well as in reduction of intensity and duration of postoperative air leakage.  相似文献   
36.
Accordingtothedatafromepidemiology,thein-cidenceofcancerrisessteadilywithadvancingage.Age?specificincidenceratesfromtheThirdNationalCancerSurveyoftheUnitedStatesrevealedthattheriskofcancerdevelopmentinthe6thdecadeoflifeisapproximately1%,whichincreasesto2%inthe81styearoflife(1).Theincidencesofmostgyneco-logiccancersincludingcervicalcancer,endometrialcancer,ovariancancerandvulvarcancerpeakaftertheageof60years(2-4).Surgeryisoneofthemaintreatmentoptionsforgynecologiccancerandmaybringaboutsomeeff…  相似文献   
37.
目的 研究在IL 2和IL 4作用下 ,趋化性细胞因子受体CCR3在人生发中心 (germinalcenter,GC)B细胞上的表达及其功能特性。方法 采用流式细胞术检测人GCB细胞上CCR3表达和在CCR3配体eotaxin作用下B细胞的凋亡 ,实时定量RT PCR和Northernblot法检测GCB细胞内CCR3mRNA的表达 ,淋巴细胞趋化和黏附试验检测B细胞的趋化和黏附能力。结果 人GCB细胞极低表达趋化性细胞因子受体CCR3,经IL 2和IL 4作用后 ,GCB细胞高表达CCR3,但此时CCR3不能在其配体作用下诱导GCB细胞的趋化和黏附功能 ,而是诱导GCB细胞凋亡。结论 IL 2和IL 4联合诱导人GCB细胞CCR3表达 ,CCR3可能具有死亡受体的功能。  相似文献   
38.
Cardiac insufficiency, coronary heart disease, and arrhythmia are not only more frequent in elderly patients, they are very often combined. By reason of cardiac morbidity and general morbidity as well as changed physiological and pathophysiological conditions, diagnosis of cardiac disease in elderly patients is more difficult. These conditions also apply to modifications in the therapy of cardiac diseases in advanced age. Especially pharmacodynamic and pharmacokinetic effects in advanced age combined with multimorbidity also account for the risk of interactions because of the simultaneous application of different pharmacological groups.  相似文献   
39.
OBJECTIVES: The use of OKT3 for treatment of advanced high-grade acute rejection episodes eventually can result in cytokine release and consecutive pulmonary edema. Temporary extracorporeal membrane oxygenation (ECMO) bridging can be used to overcome this crucial period before the beneficial effects of OKT3 can be observed. METHODS: We summarize our experience with three patients, who underwent lung transplantation and presented with severe acute rejection episodes. OKT3 had to be initiated due to insufficient response to standard rejection therapy with corticosteroids. Upon initiation of OKT3 treatment, a massive life-threatening deterioration of lung function in spite of heavily invasive respirator treatment was seen and temporary ECMO support was imperative to support graft function. Results of this treatment were retrospectively reviewed. RESULTS: In all cases femoro-femoral veno-arterial ECMO was used for support of the impaired graft and after a period of 4-5 days led to a massive improvement of graft function. In the further course two patients could be discharged from hospital and are still alive 30 and 36 months, respectively, after the described incident. One patient died 4 months later due to liver failure. CONCLUSIONS: We conclude that the use of ECMO support in patients experiencing significant side effects from OKT3 therapy is a useful and effective therapeutic tool to overcome the initial critical period until the lung has sufficiently recovered.  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