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   574962篇
  免费   50077篇
  国内免费   36108篇
耳鼻咽喉   5270篇
儿科学   6575篇
妇产科学   9243篇
基础医学   67816篇
口腔科学   9706篇
临床医学   75424篇
内科学   89081篇
皮肤病学   5994篇
神经病学   31489篇
特种医学   21835篇
外国民族医学   291篇
外科学   60265篇
综合类   87656篇
现状与发展   113篇
一般理论   69篇
预防医学   36380篇
眼科学   16279篇
药学   58270篇
  481篇
中国医学   30039篇
肿瘤学   48871篇
  2024年   5708篇
  2023年   8024篇
  2022年   20219篇
  2021年   26059篇
  2020年   19733篇
  2019年   17450篇
  2018年   18434篇
  2017年   16410篇
  2016年   15742篇
  2015年   23509篇
  2014年   29482篇
  2013年   26992篇
  2012年   39711篇
  2011年   44766篇
  2010年   28384篇
  2009年   22185篇
  2008年   30113篇
  2007年   30184篇
  2006年   29859篇
  2005年   29679篇
  2004年   21134篇
  2003年   19505篇
  2002年   16810篇
  2001年   14798篇
  2000年   14942篇
  1999年   15912篇
  1998年   9524篇
  1997年   9459篇
  1996年   7271篇
  1995年   6753篇
  1994年   5742篇
  1993年   4073篇
  1992年   5492篇
  1991年   4669篇
  1990年   3964篇
  1989年   3496篇
  1988年   2915篇
  1987年   2598篇
  1986年   2171篇
  1985年   1678篇
  1984年   1022篇
  1983年   753篇
  1982年   472篇
  1981年   439篇
  1980年   383篇
  1979年   472篇
  1978年   225篇
  1977年   212篇
  1974年   230篇
  1973年   189篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
51.
Bradyarrhythmia requiring permanent pacing after heart transplantation remains a common problem. Sinus node dysfunction is the most common indication, and late onset of atrioventricular (AV) block has rarely been reported. We report the case of a patient who developed advanced AV block at 41 months after transplantation. Right bundle branch block with progressive increase of QRS complex duration was noted in serial electrocardiograms. At the time of late AV block development, the patient did not have acute rejection and coronary angiogram was normal. The mechanism of late onset of AV block is unclear, but it may be caused by progressive conduction.  相似文献   
52.
53.
目的与方法 采用深刺和浅刺对丙酸睾酮所致前列增生症(BPH)大鼠模型进行干预,研究其作用殊同。结果 针刺组前列腺,膀胱指数明显小于模型组;形态学观察,针刺组较模型组增生明显减轻,腺上皮呈单层柱状,腺体数目明显减少,间质充血,钙化明显减轻,结缔组织无增生,腺腔内分泌物减少。深刺组好于浅刺组。结论 深刺对实验性BPH大鼠的干预作用好于浅刺方法。  相似文献   
54.
现代医学200词——138.黏附分子   总被引:1,自引:0,他引:1  
喻磊  王心 《日本医学介绍》2005,26(10):479-480
所谓黏附分子是指存在于细胞表面,参与细胞间或细胞与细胞外基质的粘附的分子群的总称。广义来说,纤维连结蛋白、层粘连蛋白、透明质酸等细胞外基质的构成成分也是由细胞分泌并存在于细胞表面,也可归入黏附分子的范畴。但狭义所指的黏附分子是指贯通细胞膜的糖蛋白或构成细胞膜的糖脂质。膜贯通型糖蛋白黏附分子按其构造特征可分为若干家族。在免疫系统中的黏附分子主要分为整合素家族、免疫球蛋白超家族、选择素家族、钙粘素家族、连接蛋白家族以及唾液粘蛋白家族等。  相似文献   
55.
In this work the feasibility of separating fat and water signals using the balanced steady-state free precession (SSFP) technique is demonstrated. The technique is based on the observation (Scheffler and Hennig, Magnetic Resonance in Medicine 2003;49:395-397) that at the nominal values of TE = TR/2 in SSFP imaging, phase coherence can be achieved at essentially only two orientations (0 degrees and 180 degrees ) relative to the RF pulses in the rotating frame, under the assumption of TR < T2, and independently of the SSFP angle. This property allows in-phase and out-of-phase SSFP images to be obtained by proper choices of the center frequency offset, and thus allows the Dixon subtraction method to be utilized for effective fat-water separation. The TR and frequency offset for optimal fat-water separation are derived from theories. Experimental results from healthy subjects, using a 3.0 Tesla system, show that nearly complete fat suppression can be accomplished.  相似文献   
56.
Purpose Post operative monitoring is crucial for the success of microsurgical free tissue transfer. Sophisticated and expensive methods are available for monitoring. We propose a novel technique using digital photography and the internet as a reliable and cost effective method to monitor free tissue transfers. Methods 163 micro‐vascular procedures were monitored using this technique over 8 months. Serial photographs taken to show flap color. Capillary refill time, pin prick‐ bleed time and color and hand held Doppler signal was recorded in the movie mode of a standard 5 mega pixel camera with duration of 15 seconds. Data was sent to the surgeon at regular intervals and or as deemed necessary. Results Analysis of the 67 cases is presented. 5 re‐explorations were done. The early diagnosis of venous congestion was possible using this technique. Timely intervention contributed to the success of the re‐explorations and these flaps could be salvaged. The file size of images was in the range of 1 MB–6 MB. The file size of an entire set of images ranged about 7 MB–9 MB. These were sent across the ADSL internet lines. Conclusion The use of the digital images and the internet allow reconstructive surgeons to have a reliable picture of the state of their free tissue transfers. This permits decrease in observer error and saves valuable time which otherwise needs to be spent to verify situations of doubt and offers an ideal solution to the logistic problem of having to visit the patient in case of doubt.  相似文献   
57.
58.
59.
We have developed a universal ovarian cancer cell targeting vehicle that can deliver biotinylated therapeutic drugs. A single-chain antibody variable domain (scFv) that recognizes the CA125 antigen of ovarian cancer cells was fused with a core-streptavidin domain (core-streptavidin-VL-VH and VL-VH-core-streptavidin orientations) using recombinant DNA technology and then expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed in a shaker flask culture, extracted from the periplasmic soluble protein, and affinity purified using an IMAC column. The two distinct activities (biotin binding and anti-CA125) of the bfFp were demonstrated using ELISA, Western blot and confocal laser-scanning microscopy (CLSM). The ELISA method utilized human NIH OVCAR-3 cells along with biotinylated bovine serum albumin (B-BSA) or biotinylated liposomes, whereas, the Western blot involved probing with B-BSA. The CLSM study has shown specificity in binding to the OVCAR-3 cell-line. ELISA and Western blot studies have confirmed the bifunctional activity and specificity. In the presence of bfFp, there was enhanced binding of biotinylated antigen and liposome to OVCAR-3 cells. In contrast, the control EMT6 cells, which do not express the CA125 antigen, showed minimal binding of the bfFp. Consequently, bfFp based targeting of biotinylated therapeutic drugs, proteins, liposomes, or nanoparticles could be an alternative, convenient method to deliver effective therapy to ovarian cancer patients. Peritoneal infusion of the bfFp-therapeutic complex could also be effective in locally targeting the most common site of metastatic spread.  相似文献   
60.
The adequate treatment of methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis has intrigued clinicians for some time. As the resistance of these pathogens, coupled with the increase in community-acquired cases, continues steadily to rise, clinicians are finding it useful to employ multi-modal approaches for efficacious treatment. The authors present a single case report of a patient with recurrent MRSA osteomyelitis, lumbar paraspinal and epidural abscess. He was found to have decreased muscle strength and was hyporeflexic in the involved extremity. Serum testing demonstrated MRSA bacteremia. Neuroimaging studies revealed evidence of paraspinal abscess and a presumed herniated nucleus pulposus at the L5/S1 interspace with significant nerve root compromise. Despite antimicrobials, his symptoms persisted, necessitating surgical exploration. At surgery, paraspinal and epidural abscesses were encountered and debrided; however, no herniated disc was visualized. This case demonstrates the diagnostic and therapeutic dilemmas with which these lesions present. We postulate that the MRSA osteomyelitis/discitis pathogens were walled off in the disc space and subsequently inoculated the soft tissues with ensuing bacteremia. We concur that antimicrobial treatment should be the first line of therapy for these patients; however, surgical debridements and cautious spinal instrumentation should be employed where appropriate.  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