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   86959篇
  免费   10386篇
  国内免费   4754篇
耳鼻咽喉   962篇
儿科学   1613篇
妇产科学   742篇
基础医学   5146篇
口腔科学   1968篇
临床医学   11593篇
内科学   9012篇
皮肤病学   1262篇
神经病学   2384篇
特种医学   3695篇
外科学   7764篇
综合类   21603篇
现状与发展   13篇
一般理论   1篇
预防医学   11200篇
眼科学   1035篇
药学   9038篇
  117篇
中国医学   8404篇
肿瘤学   4547篇
  2024年   412篇
  2023年   1385篇
  2022年   2737篇
  2021年   3494篇
  2020年   3173篇
  2019年   1669篇
  2018年   2177篇
  2017年   2761篇
  2016年   2266篇
  2015年   3818篇
  2014年   4757篇
  2013年   6148篇
  2012年   7621篇
  2011年   7963篇
  2010年   7320篇
  2009年   6698篇
  2008年   6407篇
  2007年   6163篇
  2006年   5418篇
  2005年   4270篇
  2004年   3006篇
  2003年   2449篇
  2002年   1962篇
  2001年   1859篇
  2000年   1279篇
  1999年   666篇
  1998年   426篇
  1997年   436篇
  1996年   429篇
  1995年   343篇
  1994年   276篇
  1993年   257篇
  1992年   188篇
  1991年   162篇
  1990年   144篇
  1989年   167篇
  1988年   141篇
  1987年   144篇
  1986年   121篇
  1985年   123篇
  1984年   93篇
  1983年   90篇
  1982年   69篇
  1981年   74篇
  1980年   53篇
  1979年   38篇
  1978年   34篇
  1977年   40篇
  1976年   39篇
  1971年   30篇
排序方式: 共有10000条查询结果,搜索用时 406 毫秒
961.
为探讨、分析氩激光治疗视网膜阻塞新生血管的疗效。氩激光治疗视网膜静脉塞新生血管55例,中央静脉塞行全视网膜光凝。分支静脉阻塞区域播散性光凝,光斑200-500μm,时间0.1-0.2s,能量0.12-0.4w,Ⅱ级光斑,蓝绿色光波,黄斑格栅光凝光斑100μm,时间0.1s,能量视病情而定,以Ⅰ级反应为度,绿色光波。结果:55例中44例有效,新生儿血管消嫁总有效率80%,无效11例(其中视盘有新生血  相似文献   
962.
目的:观察新生儿缺氧缺血性脑病(HIE)心肌酶活性化及心脏受损的情况,方法:采用连续监测法等方法检测了110例新生儿HIE与45例正常新生儿脐血心肌酶谱测定值比较。结果:血清心肌酶谱HIE新生儿组明显高于新生儿正常对照组(P〈0.01),而重度HIE组显高于轻、中度HIE组(P〈0.01)。结论:新生儿HIE做心肌产谱测定是诊断其心肌损害、损害程度和估计预后的临床指标之一,有助于临床早期预测新生儿HIE心肌损害有给予早期治疗。  相似文献   
963.
The biodistribution of indium-111/yttrium-88-labeled B3 monoclonal antibody, a murine IgG1k, was evaluated in non-tumor-bearing mice. B3 was conjugated to either 2-(p-SCN-Bz)-6-methyl-DTPA (1B4M) or 2-(p-SCN-Bz)-1,4,7,10 tetraazacyclododecane tetra-acetic acid (2B-DOTA) and labeled with 111In at 1.4–2.4 mCi/mg and 88Y at 0.1–0.3 mCi/mg. Non-tumor-bearing nude mice were co-injected i.v. with 5–10 Ci/4–10 g of 111In/88Y-labeled B3 conjugates and sacrificed at 6 h and daily up to 168 h post-injection. Mice injected with 111In/88Y (IB4M)-B3 showed a similar biodistribution of the two radiolabels in all tissues except the bones, where significantly higher accretion of 88Y than 111In was observed, with 2.8% ± 0.2% vs 1.3% ± 0.16% ID/g in the femur at 168 h, respectively (P<0.0001). In contrast, mice receiving the 111In/88Y-(DOTA)-B3 conjugate showed significantly higher accumulation of 111In than 88Y in most tissues, including the bones, with 2.0% ± 0.1% vs 1.2% ± 0.09% ID/g in the femur at 168 h, respectively (P<0.0001). Whereas the ratios of the areas underneath the curve (%ID × h/g) in the blood, liver, kidney and bone were 0.96, 1.12, 1.13, and 0.74 for 111In/88Y-(IB4M)-B3 and 0.84, 1.23, 1.56, and 1.31 for 111In/88Y (DOTA)-B3, respectively, ratios 1 were observed between 111In-(IB4M)-B3 and 88Y-(DOTA)-B3. In summary, while neither IB4M nor DOTA was equally stable for 111In and 88Y, the fate of 88Y- (DOTA)-B3 could be closely traced by that of 111 In-(IB4M)-B3.  相似文献   
964.
An important aspect of primary care physician availability is the retention of physicians once they have located. While retention has been under-researched compared to recruitment, it is especially important in rural areas where physician shortages already exist. This study reports the results of a retention survey completed by 132 primary care physicians in rural eastern Kentucky. The survey sets up an objective, hypothetical retention scenario and asks physicians to respond to structured questions and to an open-ended question about factors not appearing in the survey. In response to the structured portion of the survey, physicians indicate that relief coverage is the most important factor in rural physician retention. A content analysis of 75 open-ended responses reveals that besides the other factors in the survey, "sociocultural integration" is the pre-eminent retention issue for rural practitioners. This article concludes that the role of the local rural community may be more important in retention than in recruitment. Finally, it is suggested that additional in-depth qualitative research be conducted within the local contexts to enhance the understanding of rural physician retention processes.  相似文献   
965.
SCH 42354, a neutral metalloendopeptidase (NEP) inhibitor, is the pharmacologically active form of the prodrug SCH 42495. It exerts antihypertensive effects by potentiating atrial natriuretic peptide (ANP) activity through inhibition of its hydrolysis by NEP. The objective of this study was to characterize the pharmacokinetics (PK) and pharmacodynamics (PD) of SCH 42354 in hypertensive males. SCH 42495 12.5 to 400 mg was administered orally to hypertensive men twice daily in a double-blind, placebo controlled multiple-dose parallel group design. Plasma SCH 42354 concentration and diastolic blood pressure (DBP) data were used to develop a PK-PD model using two approaches. In the first (non-integrated) approach, the link model was used to predict effect-site concentrations, and was applied to data obtained at the 300 and 400 mg BID doses only; data at the other (lower) doses were not amenable to modeling because of high variability. Effect-site concentration and DBP data were then fit to a sigmoid Emax PD model. For the 300 mg BID dose, PD parameters were: maximum effect (Emax), 8.1mmHg; no-drug effect (Eo), 3.6 mmHg; concentration corresponding to 50% of maximum response (EC50), 0.87 g·ml–1; and gamma, 3.9. In the second (time-integrated) approach, plasma SCH 42354 concentration and effect data obtained over the entire dose range were integrated with respect to time. Average plasma concentration and DBP data were then fit to a simple Emax PD model. PD parameters obtained over the dose range were: Emax, 10.3 mmHg; Eo, 2.0 mmHg; and EC50, 0.7 g·ml–1. These were similar to the estimates obtained from the first approach, demonstrating that the integrated (average) data allow PK-PD modeling over the (entire) dose range. The analysis showed that, at steady-state, a 400 mg BID dose of SCH 42495 produced an approximate 10 mmHg decrease in DBP in hypertensive males; the average plasma SCH 42354 concentration attained at this dose was approximately 1.8 g·ml–1.  相似文献   
966.
目的:探讨体外模型评价神经生长因子(nerve growth factor,NGF)抗体在膝骨关节炎(knee osteoarthritis,KOA)疼痛模型中的作用。方法:选取30只8周龄雄性SPF大鼠,分为空白组10只;其余20只行右膝关节单碘乙酸 (monoiodoacetate,MIA) 注射,制备骨性关节炎疼痛模型。造模成功后,再根据干预方法不同分为对照组(生理盐水腹腔注射)、治疗组(抗NGF 腹腔注射),每组10只。所有动物右膝关节进行荧光金 (fluorogold,FG) 逆行神经示踪剂注射。分别在治疗前,治疗后1、2周使用猫道步态分析系统评估步态。治疗后3周,从L3-L5水平切除右背根神经节(dorsal root ganglia,DRG),进行降钙素基因相关肽 (calcitonin gene-related peptide,CGRP) 免疫染色,并计算DRG数量。结果:在使用猫道系统的步态分析中,与空白组相比,对照组、治疗组占空比、摆动速度和触地面积比率明显降低(P<0.05);与对照组相比,治疗组占空比、摆动速度明显改善(P<0.05),触地面积比率与空白组比较,差异无统计学意义(P>0.05)。对照组中FG标记的DRG神经元数量高于治疗组和空白组(P<0.05);对照组CGRP表达上调,与治疗组比较,差异有统计学意义(P<0.05)。结论:腹腔注射抗 NGF抗体抑制了步态损伤和 DRG 神经元中CGRP 的上调。这些发现提示抗神经生长因子治疗可能对治疗膝关节疼痛有价值。NGF可能是治疗KOA疼痛的重要靶点。  相似文献   
967.
为了解血源乙型肝炎(乙肝)疫苗的免疫持久性,对澄江县1991~1995年按照0、1、6个月免疫程序完成血源乙肝疫苗接种的人群,按接种后间隔1~5年分组,每组随机抽取100名儿童,采末梢血,共得517份免疫者的血清样品.用酶联免疫吸附试验(ELISA)检测抗-HBs、HBsAg。结果表明,接种乙肝疫苗2年内抗-HBs阳性率在90%以上,以后随间隔年眼的延长而明显下降,间隔5年降至60%,人群平均保护率达78.57%.  相似文献   
968.
1998年5月,我们在江苏省新沂市选择1~1.5岁健康儿童进行流行性乙型脑炎(乙脑)减毒活疫苗免疫学效果观察.免疫前和免疫后1个月各采血检测乙脑反向被动血凝(RPHI)抗体.检测到合格双份血清87人,抗体测定免疫前阴性44人.其免疫后抗体阳转率为93.18%,免疫前阳性43人,其免疫后抗体≥4倍增长率为34.88%,表明乙脑减毒活疫苗的免疫成功率是较高的.  相似文献   
969.
Research Objectives: To develop population-based estimates of estrogen replacement therapy use rates in 1995 among women over age 65 living in the community; to estimate the impact of socioeconomic and health characteristics on estrogen use. Method: Estimates are based on a large, nationally representative sample of Medicare beneficiaries; detailed self-report data were merged with Medicare claims. Results: Overall, 13.1% of women reported use of estrogen replacement therapy in 1995. Estrogen users were more likely to be white, age 65–74, with private insurance, high income, history of osteoporosis and heart problems, no history of breast cancer, and a patient of gynecologists. Conclusions: Estrogen use was substantially lower among the socioeconomically disadvantaged, controlling for medical history variables, suggesting considerable inequity in access to estrogen replacement therapy treatment.  相似文献   
970.
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