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   15923篇
  免费   949篇
  国内免费   442篇
耳鼻咽喉   60篇
儿科学   320篇
妇产科学   242篇
基础医学   1604篇
口腔科学   133篇
临床医学   1689篇
内科学   2458篇
皮肤病学   116篇
神经病学   618篇
特种医学   314篇
外科学   1060篇
综合类   3192篇
预防医学   1459篇
眼科学   59篇
药学   2647篇
  7篇
中国医学   758篇
肿瘤学   578篇
  2023年   184篇
  2022年   410篇
  2021年   535篇
  2020年   497篇
  2019年   392篇
  2018年   394篇
  2017年   451篇
  2016年   496篇
  2015年   527篇
  2014年   1156篇
  2013年   1106篇
  2012年   1002篇
  2011年   1123篇
  2010年   877篇
  2009年   720篇
  2008年   745篇
  2007年   748篇
  2006年   619篇
  2005年   531篇
  2004年   470篇
  2003年   429篇
  2002年   339篇
  2001年   308篇
  2000年   262篇
  1999年   230篇
  1998年   197篇
  1997年   181篇
  1996年   157篇
  1995年   162篇
  1994年   131篇
  1993年   137篇
  1992年   119篇
  1991年   96篇
  1990年   113篇
  1989年   98篇
  1988年   109篇
  1987年   76篇
  1986年   77篇
  1985年   179篇
  1984年   153篇
  1983年   132篇
  1982年   119篇
  1981年   110篇
  1980年   71篇
  1979年   55篇
  1978年   49篇
  1977年   33篇
  1976年   35篇
  1975年   35篇
  1973年   27篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
21.
目的 :观察血清保存方法对促甲状腺激素 (TSH)结果的影响。方法 :将甲状腺功能正常、异常患者共 10份血清 ,采用不同血清量、不同条件分组保存后测定 TSH。结果 :保存方法对 TSH结果有一定的影响。结论 :用于 TSH血清的保存量要多、要密封管口、低温保存。  相似文献   
22.
为给临床心脏术后监测心淋巴管损伤程度及可能出现的并发症提供参考指标,以手术方法阻断羊心淋巴流并对其血清相关成份进行了测定。实验发现,实验组术后谷草转氨酶(SGOT)、谷丙转氨酶(SGPT)、碱性磷酸酶(AKP)、乳酸脱氢酶(LDH)均有不同程度的增高,以SGOT增高最为明显,术前均值为47.53U,术后2天增至104.20U,高峰出现时间最早,多在术后24小时。血清离子改变中低钾最为突出,血钾在术后2天明显降低(P<0.01),术后7天逐渐恢复,术后14天恢复至术前水平。血清蛋白改变以球蛋白降低、白蛋白/球蛋白比值升高为主。提示心淋巴循环郁滞可导致心肌细胞损伤、毛细血管通透性和结构的改变。不同酶活性的变化对郁滞的敏感度存在着差异。  相似文献   
23.
本文用胶固素酶联免疫吸附试验检测了16例缺血性脑血管病(ICD)患者,14例出血性脑血管病(HCD)患者和20例健康正常人的血清IgE型循环免疫复合物(CID)水平。结果显示ICD组和HCD组IgE-CIC水平明显高于正常组(分别为P<0.001和P<0.05)。ICD组与HCD组间没有显著差异(P>0.02)。提示脑血管病的发生与IgE-CIC的形成有关。  相似文献   
24.
Twenty-six patients diagnosed as chronic schizophrenics were given injections of zuclopenthixol decanoate (cis(Z)-clopenthixol decanoate) 200 mg every 3 weeks for at least 6 months. Before treatment and on each day of injection the patients' mental state was assessed by Brief Psychiatric Rating Scale (BPRS), 18 items. A registration of side effects and basal laboratory data was also performed. Blood samples were drawn on each day of injection before injection and 3–7 days after injection (time of maximum concentration). Neuroleptic activity, which was considered equivalent to the concentration of zuclopenthixol, was determined in serum by radio-receptor assay (RRA). Based on amelioration scores ≥50% on the BPRS, 15 patients were characterized as responders and 11 as non-responders. The responder group showed a statistically significant reduction in BPRS score, whereas this was not the case for the non-responders. Apart from a few patients, the serum concentrations showed a low intra-individual variation, but a relatively high inter-individual variation. The responder group had a significantly higher mean preinjection concentration than the non-responder group, whereas no significant difference was found in day 3–7 concentrations. The fluctuation of the serum concentration expressed as the ratio between maximum (days 3–7) and minimum (pre-inj.) was found to be significantly lower for responders than for non-responders. Thus although the present study did not demonstrate a clear relationship between serum level and clinical effect, it indicates that the best antipsychotic effect is obtained with a serum concentration which fluctuates only slightly (the ratio max/min concentration not exceeding 2.1).  相似文献   
25.
Objective: To evaluate the diagnostic value of serum neuron specific enolase and Video EEG inFebrile Convulsion of childen. Method:Serum NSE was detected by RIA on the first day and the seventh day afterseizure in 40 children with simple febrile convulsion and 18 with complex febrile convulsion. Video EEG was per-formed at 1st, 7th and 30th day in all the patients. Results: There were significant differences between NSE levels at24th hour and on 7th day after convulsion (P<0.01). NSE concentrations in patients with SFC and CFC were also  相似文献   
26.
Summary A rapid and quantitative method for the determination of benzodiazepines using high-performance liquid chromatography (HPLC) with diode-array detection (DAD) is reported. The drugs were extracted from serum, blood or post-mortem blood using C18 extraction columns. Brotizolam was used as internal standard. Experiments with spiked serum/blood samples resulted in recoveries between 75% and 94% for all investigated benzodiazepines. Excellent linearity was obtained over the concentration range 5–1500 ng benzodiazepine/ml. The limit of detection was approximately 2 ng/ml. The detection of low therapeutic serum levels of highly potent benzodiazepines is also possible.   相似文献   
27.
目的探讨早产儿血清表皮生长因子水平与脑发育的关系。方法依据入选标准观察对象为自2005年8月起连续收治入本院新生儿病房、出生24h内的胎龄为34周±3d的“正常”早产适于胎龄儿30例。采用酶联免疫吸附测定(ELISA)法,分别测定30例早产儿生后24h内和出生第8天空腹股静脉血清表皮生长因子(EGF)水平,分别为t0和t1值,计算血清EGF浓度变化的速率(Δt)。同时,在新生儿出生后6周(纠正胎龄接近40周)和纠正1月龄时进行NBNA评分测定。并将以上实验室数据与新生儿行为神经测定(NBNA)评分值及差值、早产儿出生后的头围增长值及增长速率进行Pearson相关分析。如果P值<0.05,则认为差有统计学意义。结果30例早产儿观察对象t0为(234.71±58.07)pg/ml,t1为(347.81±87.49)pg/ml,Δt为(16.16±9.94)(12.14、15.20)pg/ml/d;Pearson相关分析显示2次NBNA评分结果及差值、出生后6周和纠正1月龄时的头围增长值/增长速率与t0值无相关性(P>0.05);2次NBNA评分结果及差值、出生后6周和纠正1月龄时的头围增长值/增长速率与t1和Δt之间有相关性(P<0.05)。结论研究结果表明,早产儿出生后血清EGF浓度呈上升趋势,提示早产儿出生后体内EGF合成和释放增加,可能促进脏器成熟和组织修复;更重要的是,早产儿出生1周时高水平血清EGF浓度和/或较快上升速率者,其出生后头围增长速度也快,可能有较好的脑发育水平、远期预后良好。  相似文献   
28.
Temperature sensitive liposomes (TSL) containing adriamycin (ADM) and cytarabine (Ara-C) were prepared. ADM and Ara-C were selected as model compounds of amphiphilic and hydrophilic drug, respectively. Encapsulation efficiency of ADM entrapped into TSL was about twice greater than that of Ara-C. It might be due to different polarity of the drugs. Lipid compositions of TSL had no effect on the encapsulation efficiency of drugs. Thermal behavior of TSL using a differential scanning calorimetry (DSC) was also investigated. Phase transition temperature (Tc) of TSL was dependent on the lipid compositions of TSL.ADM broadened thermogram of TSL but Ara-C did not. However, Tc of TSL was not changed by any drug. Release rate of drugs was highly dependent on temperature. The release profile of ADM was similar to that of Ara-C. The maximum release rate of drugs from TSL was occurred at the near Tc and observed at 39–41°C for DPPC (Dipalmitoylphosphatidylcholine) only, 52–54°C for DSPC (Distearoylphosphatidylcholine) only, 41–43°C for DPPC and DSPC (3∶1), and 43–45°C for DPPC and DSPC (1∶1), respectively. Effect of human serum albumin (HSA) on the release rate of ADM was investigated. HSA had no significant effect on the release of ADM below Tc. However, ADM release from TSL was increased at the near and above Tc. The HSA-induced leakage of drug may result from the interaction of liposomal constituents with HSA structure at the near Tc. From the fact that the release profiles of ADM from freshly prepared TSL and stored TSL for 1 week at 4°C was not changed, the TSL was considered to be stable for at least 1 week at 4°C. Based on these findings, TSL may be useful to deliver drugs to preheated target sites due to its thermal behaviors.  相似文献   
29.
采用放射免疫法测定60例心血管病患儿的血浆心钠素,结果,在心功能不全,先天性心脏病、心肌炎者,明显高于正常组;心功能不全组明显高于非心功能不全组。非心功能不全的心血管疾患(如:先天性心脏病、心肌炎)之间无显著差异。说明血浆心钠素测定可作为心功能不全判断指标,并可指导治疗。  相似文献   
30.
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