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   70451篇
  免费   7572篇
  国内免费   4504篇
耳鼻咽喉   1216篇
儿科学   1031篇
妇产科学   511篇
基础医学   5184篇
口腔科学   1454篇
临床医学   8768篇
内科学   6699篇
皮肤病学   779篇
神经病学   2002篇
特种医学   3088篇
外国民族医学   13篇
外科学   6003篇
综合类   17508篇
现状与发展   19篇
一般理论   3篇
预防医学   7014篇
眼科学   1175篇
药学   8492篇
  100篇
中国医学   7332篇
肿瘤学   4136篇
  2024年   470篇
  2023年   1286篇
  2022年   3130篇
  2021年   3862篇
  2020年   3114篇
  2019年   1966篇
  2018年   1977篇
  2017年   2395篇
  2016年   1834篇
  2015年   3104篇
  2014年   3828篇
  2013年   4389篇
  2012年   6400篇
  2011年   6696篇
  2010年   5421篇
  2009年   4652篇
  2008年   5024篇
  2007年   4725篇
  2006年   4100篇
  2005年   3181篇
  2004年   2331篇
  2003年   2150篇
  2002年   1657篇
  2001年   1459篇
  2000年   1030篇
  1999年   591篇
  1998年   259篇
  1997年   228篇
  1996年   207篇
  1995年   160篇
  1994年   134篇
  1993年   81篇
  1992年   113篇
  1991年   92篇
  1990年   91篇
  1989年   64篇
  1988年   58篇
  1987年   58篇
  1986年   43篇
  1985年   35篇
  1984年   19篇
  1983年   16篇
  1982年   12篇
  1981年   7篇
  1980年   7篇
  1979年   16篇
  1978年   6篇
  1974年   5篇
  1966年   6篇
  1965年   5篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
角膜溃疡穿孔的修复与修复材料的选择   总被引:2,自引:0,他引:2  
廖世煌  张悦 《眼科研究》1995,13(3):169-170
总结21例用不同材料修复角膜穿孔的病例,修复材料分别为结膜瓣、硅胶板、断层自体皮片和同种异体角膜。结膜瓣遮盖仅2/3保存眼球,愈合后视力差,并发症多;硅胶板可在穿孔大、情况紧急时作暂时封孔保存眼球之用;自体断层皮片术后不久即溶解,角膜移植者7眼中6眼保存了眼球,且有5例植片透明,视力0.1以上。  相似文献   
22.
经皮冠状动脉介入治疗(PCI)是近年发展迅速的冠心病治疗手段,具有安全性高、创伤小、适应证广、恢复快等优点,但由于其针对冠状动脉血管腔内进行操作,因此发生各种并发症在所难免,如不及时妥善处理可能给患者带来较大危害.全国第二次(1997~1998年)和第三次(1999~2001年)PCI注册登记资料结果显示,PCI围术期重要并发症发生率分别为11.0%和6.9%,病死率分别为0.37%和0.31%.全军第三次(2003~2004年)PCI注册登记资料结果显示PCI围术期并发症发生率约4.2%.尽管随着PCI整体技术水平的提高其并发症有下降趋势,但仍有一定的发生率.老年冠心病患者由于冠状动脉病变多较重,且常合并全身其他脏器疾病,其PCI围术期并发症的发生率亦高于一般人群.因此,了解和掌握PCI常见并发症的原因、表现及其防治策略有助于进一步提高老年PCI的疗效和安全性.  相似文献   
23.
板股韧带的MRI研究及临床意义   总被引:1,自引:0,他引:1  
目的 明确板股韧带正常MRI表现 ,建立由它所致假撕裂与外侧半月板后角真撕裂的鉴别方法。资料与方法 采用 6 0侧正常膝进行矢状和冠状位MR扫描 ,观察板股韧带的MRI表现。结果 板股韧带显示率为88.3% (5 3侧 ) ,其中板股前韧带为 2 6 .7% (16侧 )、板股后韧带为 86 .7% (5 2侧 )和两条韧带同时存在为 2 3.3% (14侧 )。板股韧带在矢状像上表现为位于后交叉韧带前或后方的类圆形或短棒状低信号结构 ,而在冠状像上表现为自外侧半月板后角至股骨内侧髁外侧面的条带样低信号结构。在矢状像上 ,5 2 .8% (2 8/5 3)板股韧带与外侧半月板后角之间显示出一线样高信号 ,被称为假撕裂 ,易与外侧半月板后角撕裂混淆。但假撕裂仅有两种走行方向即后下斜行 (2 1/2 8)或垂直方向 (7/2 8)。结论 根据假撕裂位置、方向以及冠状像和连续矢状面的观察 ,可正确区分外侧半月板后角真假撕裂  相似文献   
24.
目的 :探讨夜间电子生物阻抗测量装置 (NEVA)在阴茎勃起功能障碍的诊断中的应用价值。方法 :对 4 1例主诉阴茎勃起功能障碍者 (障碍组 ) 19例主诉无勃起功能障碍但有射精障碍者 (无障碍组 )进行NEVA检测。结果 :障碍组夜间试验中的夜间勃起的次数、阴茎勃起的最大体积改变、最长持续时间等客观指标均要差于无障碍组 ,差异有统计学意义 (P <0 .0 1)。结论 :NEVA为非侵入性检测、可鉴别心理性阴茎勃起功能障碍和严重的器质性勃起功能障碍 ,且对勃起功能障碍的定性和定量具有一定的客观性。  相似文献   
25.
岳焕勋  刘小章  张志红  李顺强 《四川医学》2004,25(11):1194-1195
目的 对使用新型聚氨酯(Pu)男用避孕套的可行性和可接受性进行初步观察。方法 对30对健康已婚夫妇为期6周360次使用国产PU避孕套的效果进行问卷调查。结果 避孕套总破裂率(临床破裂 非临床破裂)为2.22%,临床滑脱率为16.5%,使用观察期间无意外妊娠发生。结论 新型PU避孕套的破裂率和滑脱率分别相近于和高于报道的乳胶避孕套使用情况,感官指标反映PU避孕套具有良好的可接受性。  相似文献   
26.
目的 :营造良性竞争的机制和氛围 ,全面提高护理质量。方法 :通过资格认定、理论技术考试、民主测评及双项选择 ,由护理部聘任。结果 :较好地进行了人力资源的开发 ,竞聘上岗后的护士有责任感和使命感 ,工作积极主动 ,自觉地成为科室各项工作的带头人。加之岗位工资的兑现 ,更有利于护士长在科室开展工作 ,使科室各项护理工作质量显著提高。结论 :良性的竞争运行机制 ,使优秀护理人才脱颖而出 ,体现能级对应的原则 ,从而使护理质量不断提高。  相似文献   
27.
BACKGROUND: Under the normal circumstance, there exist some synapses with inactive functions in central nervous system (CNS), but these functions are activated following nerve injury. At the early stage of brain injury, the abnormal functions of brain are varied, and they have very strong plasticity and are corrected easily. OBJECTIVE: To observe the changes of neuronal morphology in hippocampal CA1 region and memory function in newborn rats with hypoxic-ischemic encephalopathy(HIE) from ischemia 6 hours to adult. DESIGN: Completely randomized grouping, controlled experiment. SETTING: Taian Health Center for Women and Children; Taishan Medical College. MATERIALS: Altogether 120 seven-day-old Wistar rats, of clean grade, were provided by the Experimental Animal Center, Shandong University of Traditional Chinese Medicine. Synaptophysin (SYN) polyclonal antibody was provided by Maixin Biological Company, Fuzhou. METHODS: This experiment was carried out in the Laboratory of Morphology, Taishan Medical College between October 2000 and December 2003. ① The newborn rats were randomly divided into 2 groups: model group and control group, 60 rats in each group. Five rats were chosen from each group at postoperative 6 hours, 24 hours, 72 hours, 7 days, 2 weeks and 3 weeks separately for immunohistochemical staining. Fifteen newborn rats were chosen from each group at postoperative 4 weeks and 2 months separately for testing memory ability (After test, 5 rats from each group were sacrificed and used for immunohistochemical staining)② The right common carotid artery of newborn rats of model group was ligated under the anesthetized status. After two hours of incubation, the rats were placed for 2 hours in a container filled with nitrogen oxygen atmosphere containing 0.08 volume fraction of oxygen, thus, HIE models were created; As for the newborn rats in the control group, only blood vessels were isolated, and they were not ligated and hypoxia-treated. ③ Thalamencephal tissue sections of newborn rats of two groups were performed DAB developing and haematoxylin slight staining. Cells with normal nucleous in 250 μm-long granular layer which started from hippocampal CA1 region were counted with image analysis system under high-fold optical microscope (×600), and the thickness of granular layer was measured. The absorbance (A) of positive reactant of SYN in immunohistochemically-stained CA1 region was measured. Learning and memory ability were measured with step through test 3 times successively. ④ t test and paired t test were used for comparing intergroup and intragroup difference of measurement data respectively, and Chi-square for comparing the difference of enumeration data. MAIN OUTCOME MEASURES: Comparison of cytological changes in hippocampal CA1 region and memory ability at different postoperative time points between two groups. RESULTS: Totally 120 newborn rats were involved in the result analysis. ① Cell morphological changes in hippocampal CA1 region: In the control group, with aging, perikaryon, nucleus and nucleolus in cortex of parietal lobe were significantly increased, Nissl body was compacted, the amount of neurons was declined, but the A of SYN positive reactant was relatively increased. In the model group, at postoperative each time point, neurons were seriously shrunk and dark-stained, nucleus was contracted, chromatin was condensed, nucleolus was unclear, even cells disappeared, especially the cells in 6 hours and 24 hours groups. The amount of neurons with normal morphology in hippocampal CA1 region and granular layer thickness in the model group at postoperative each time point were significantly less or smaller than those in the control group at postoperative 6 hours respectively (t =3.002-1.254, P < 0.01). The A value of SYN positive reactant at postoperative 2, 3 and 4 weeks was significantly higher than that at previous time point (t =2.011-2.716,P < 0.05-0.01). ② Test results of learning and memory ability: In the first test, there was no significant difference in the ratio of rats which kept memory ability between two groups (P > 0.05); In the third test, the ratio of rats which kept memory ability in the model group was significantly lower than that in the control group at postoperative 4 weeks and 2 months[53%(8/15),100%(15/15);60%(9/15),93%(14/15),χ 2=2.863,2.901,P < 0.01]. CONCLUSION: The destroyed hippocampal structure induces the decrease of learning and memory ability of developmental rats. Early interference can increase the quality of neurons and also promote functional development of the nervous system.  相似文献   
28.
BP神经网络是目前应用最广泛的人工神经网络模型,本文详细阐述了BP神经网络的原理和特点,并论述了其在药学研究中的应用。  相似文献   
29.
Two hundred Type 2 diabetic patients newly referred to the diabetes centre at a large university teaching hospital were studied over an 8-month period. Patients completed a diabetes knowledge questionnaire, and specified their educational priorities by selecting six diabetes-related topics from a list of 14. After giving 1 h of individual education and using the same list, the educators selected six topics which they considered to be most important for that particular patient to know. Choice of educational priorities differed between the patients and the corresponding educator (p less than 0.001). In only 38% of cases did the educators' first three priorities coincide with those of the patients. The major discrepancies were in the selection of 'sick day management' and 'complications', especially favoured by patients, as against 'oral hypoglycaemic agents' and other therapy-related topics, especially favoured by educators. Diabetes knowledge was a determinant of educational priority for patients (p less than 0.001) but not educators. In contrast, only the educators' overall choices were affected by duration of diabetes (p less than 0.001). Diabetes treatment type influenced both patients' and educators' selection of priorities (p less than 0.001). We conclude that an educational strategy which relies on health professionals' perceptions to determine what diabetic patients need to know may be inadequate.  相似文献   
30.
Summary In this study the technique of labelling the cell membrane with DPH fluorescence polarization was used to observe the membrane fluidity of B lymphocytic cell lines and tonsillar cells from healthy persons; the modulation effect on membrane-fluidity induced by McAbs against isotypic and idiotypic determinants of IgM from patients with leukemia was studied as well. The expression of the corresponding isotypic and idiotypic determinants of IgM on the cell membrane was determined. The results show that the membrane fluidity of leukemic cell lines is remarkably higher than that of tonsillar cells from healthy persons, and McAbs against isotypic determinants of leukemic IgM can enhance the membrane fluidity of all kinds of cells mentioned above. However, the anti-idiotypic monoclonal antibody increased only the membrane fluidity of leukemic cell lines. These results indicated that there was a close relationship between the effect of McAbs on cell membrane fluidity and the expression of corresponding isotypic and idiotypic determinants of IgM on the cell membrane.  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