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   15547篇
  免费   1274篇
  国内免费   378篇
耳鼻咽喉   28篇
儿科学   159篇
妇产科学   73篇
基础医学   1017篇
口腔科学   455篇
临床医学   1059篇
内科学   1378篇
皮肤病学   503篇
神经病学   744篇
特种医学   1203篇
外科学   671篇
综合类   1788篇
一般理论   1篇
预防医学   4192篇
眼科学   101篇
药学   1919篇
  5篇
中国医学   961篇
肿瘤学   942篇
  2024年   16篇
  2023年   147篇
  2022年   256篇
  2021年   623篇
  2020年   520篇
  2019年   494篇
  2018年   467篇
  2017年   471篇
  2016年   538篇
  2015年   531篇
  2014年   966篇
  2013年   1068篇
  2012年   1017篇
  2011年   1298篇
  2010年   899篇
  2009年   778篇
  2008年   754篇
  2007年   752篇
  2006年   653篇
  2005年   540篇
  2004年   494篇
  2003年   416篇
  2002年   372篇
  2001年   392篇
  2000年   278篇
  1999年   258篇
  1998年   215篇
  1997年   195篇
  1996年   181篇
  1995年   149篇
  1994年   171篇
  1993年   113篇
  1992年   117篇
  1991年   117篇
  1990年   90篇
  1989年   103篇
  1988年   78篇
  1987年   72篇
  1986年   50篇
  1985年   101篇
  1984年   71篇
  1983年   61篇
  1982年   61篇
  1981年   51篇
  1980年   35篇
  1979年   46篇
  1978年   19篇
  1977年   28篇
  1976年   22篇
  1974年   12篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
IntroductionSelective internal radiation therapy (SIRT) is a potential treatment of primary renal cell carcinoma (RCC) deemed unsuitable for conventional therapy. RESIRT is the first-in-human study to evaluate safety and feasibility of SIRT for primary RCC.Patients and MethodsPatients with RCC, unsuitable for, or who declined conventional therapy, were eligible. A single transfemoral micro-catheter administration of yttrium-90 (Y-90) resin microspheres (SIR-Spheres) was delivered super selectively via the renal artery to the tumour at intended radiation doses of 75, 100, 150, 200, 300 Gy and a final cohort with a procedural endpoint of “imminent stasis,” in a dose-escalation design. Post-SIRT follow-up was 12 months. Study endpoints included safety and toxicity 30-days and 12-months post-SIRT and tumour response (RECIST v1.1).ResultsIn total, 21 patients were enrolled, mean (SD) age was 75 (9.3) years, WHO performance status was 0 in 81%, 12 (57%) had stage 3 chronic kidney disease, and 7 (33%) had prior contralateral nephrectomy. Overall, 71% of patients completed 12 months of follow-up. Intended doses were delivered without any dose-limiting toxicity. Seventeen out of 21 (81%) patients experienced an adverse event (AE) from any cause within 30 days post-SIRT; all SIRT-related AEs were grade 1 to 2. Best overall tumour responses were partial response 1/21 (4.8%), stable disease 19/21 (90.5%) and progressive disease 1/21 (4.8%).ConclusionThis study demonstrated good tolerability of SIRT at all dose levels including “imminent stasis” in treating primary tumours in RCC patients otherwise unsuitable for conventional therapy. SIRT with Y-90 resin microspheres may be a feasible treatment option for RCC.  相似文献   
2.
《Brain stimulation》2020,13(4):1040-1050
BackgroundAchieving deep brain stimulation (DBS) dose equivalence is challenging, especially with pulse width tuning and directional contacts. Further, the precise effects of pulse width tuning are unknown, and recent reports of the effects of pulse width tuning on neural selectivity are at odds with classic biophysical studies.MethodsWe created multicompartment neuron models for two axon diameters and used finite element modeling to determine extracellular influence from standard and segmented electrodes. We analyzed axon activation profiles and calculated volumes of tissue activated.ResultsWe find that long pulse widths focus the stimulation effect on small, nearby fibers, suppressing distant white matter tract activation (responsible for some DBS side effects) and improving battery utilization when equivalent activation is maintained for small axons. Directional leads enable similar benefits to a greater degree. Reexamining previous reports of short pulse stimulation reducing side effects, we explore a possible alternate explanation: non-dose equivalent stimulation may have resulted in reduced spread of neural activation. Finally, using internal capsule avoidance as an example in the context of subthalamic stimulation, we present a patient-specific model to show how long pulse widths could help increase the biophysical therapeutic window.DiscussionWe find agreement with classic studies and predict that long pulse widths may focus the stimulation effect on small, nearby fibers and improve power consumption. While future pre-clinical and clinical work is necessary regarding pulse width tuning, it is clear that future studies must ensure dose equivalence, noting that energy- and charge-equivalent amplitudes do not result in equivalent spread of neural activation when changing pulse width.  相似文献   
3.
4.
5.
Concrete plants accumulate large amounts of concrete wash water. This water, which pH is highly alkaline, has a negative impact on the environment. Its reuse in fresh concrete slightly reduces its mechanical properties. The combination of concrete wash water and zeolitic by-product led to an increase of 4.6% in the compressive strength at 7 days hydration and up to 30% at 28 days hydration. The same combination led to the denser microstructure compared to the samples made with concrete wash water. This could be explained by the pozzolanic reaction of the zeolitic by-product. The complex chemical reactions of cement, zeolitic by-product, and fines presented in the concrete wash water occurred. Therefore, it was suggested the reusing method of concrete wash water together with zeolitic by-product in the fresh concrete mixtures by substituting some amount of tap water with concrete wash water. In this way, the consumption of tap water is possible to reduce in cement systems.  相似文献   
6.
摘要〓目的〓研究四腔水箱在腹外科腔镜电凝线擦拭法清洗消毒中的应用效果。方法〓通过目测法和ATP生物荧光法,对本研究的四腔水箱用于腹外科腔镜电凝线的清洗效果进行评价。结果〓传统治疗碗清洗的206件腔镜电凝线清洗质量合格率为86.4%,四腔水箱清洗的206件腹腔镜电凝线清洗质量合格率为94.6%,差异有统计学意义(P<0.01)。用四腔水箱清洗腔镜电凝线擦拭过程中的护理人员满意度较高。结论〓四腔水箱可提高腹外科腔镜电凝线清洗质量和护理人员满意度。  相似文献   
7.
8.
目的建立环境水样中痕量铜的浊点萃取(cloud point extraction,CPE)-火焰原子吸收光谱(flame atomic absorption spectrometry,FAAS)测定法。方法样品在p H 9.5的条件下,加入0.4 ml的1 mmol/L 2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(5-Br-PADAP)溶液,0.1%氯化钙溶液0.1 ml,5%(W/V)Triton X-114溶液0.8 ml,40℃加热15 min后离心,采用火焰原子吸收光谱法进行检测。结果在2~240μg/L的线性范围内,所得回归方程为A=0.002 7c+0.024 6,r=0.995 8。以3倍信噪比计算,方法的检出限为0.62μg/L,富集倍数为36.58倍,平均加标回收率为96.28%~98.08%,RSD为1.67%~3.13%。结论该方法简单、灵敏,具有良好的重现性,适用于环境水样中痕量铜的测定。  相似文献   
9.
Minesapride is a novel 5-hydroxytryptamine 4 (5-HT4) receptor partial agonist that is expected to show efficacy in patients with irritable bowel syndrome with predominant constipation and functional constipation. An open-label study was conducted to evaluate pharmacokinetics (PK) and safety of minesapride. Japanese subjects, 12 elderly and 12 young, received a single oral dose of minesapride 40 mg/day in the fasted state. Metabolite profiles were also investigated in this clinical study and in an in vitro study using cryopreserved hepatocytes. Clinical results showed that minesapride was rapidly absorbed (Cmax: 2302.1 ng/mL in the elderly group, 2117.5 ng/mL in the young group), and the plasma concentration then decreased with half-life of approximately 7 h. There were no notable PK differences between elderly and young groups. No serious adverse events (AEs) were observed. The only AE that occurred in 2 or more subjects was diarrhea. Metabolite profiles in plasma and urine were similar between elderly and young groups. No major metabolites exceeded 10% of unchanged minesapride, and results of the in vitro study suggested that there were no human-specific metabolites. From the viewpoints of PK and metabolite profiling, no dose adjustment of minesapride is warranted in elderly population without renal or hepatic impairment.  相似文献   
10.
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