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   62055篇
  免费   5861篇
  国内免费   4353篇
耳鼻咽喉   634篇
儿科学   578篇
妇产科学   599篇
基础医学   7127篇
口腔科学   1249篇
临床医学   8117篇
内科学   8818篇
皮肤病学   687篇
神经病学   2712篇
特种医学   2002篇
外国民族医学   46篇
外科学   6261篇
综合类   11205篇
现状与发展   19篇
一般理论   14篇
预防医学   4702篇
眼科学   1695篇
药学   6662篇
  74篇
中国医学   3677篇
肿瘤学   5391篇
  2024年   266篇
  2023年   1006篇
  2022年   2580篇
  2021年   3388篇
  2020年   2515篇
  2019年   2030篇
  2018年   2179篇
  2017年   1948篇
  2016年   1797篇
  2015年   2983篇
  2014年   3575篇
  2013年   3084篇
  2012年   4439篇
  2011年   4902篇
  2010年   3392篇
  2009年   2744篇
  2008年   3260篇
  2007年   3261篇
  2006年   3226篇
  2005年   3102篇
  2004年   2290篇
  2003年   2125篇
  2002年   1746篇
  2001年   1479篇
  2000年   1381篇
  1999年   1401篇
  1998年   946篇
  1997年   893篇
  1996年   650篇
  1995年   679篇
  1994年   565篇
  1993年   336篇
  1992年   378篇
  1991年   343篇
  1990年   292篇
  1989年   250篇
  1988年   204篇
  1987年   202篇
  1986年   135篇
  1985年   114篇
  1984年   65篇
  1983年   37篇
  1982年   22篇
  1981年   27篇
  1980年   8篇
  1979年   22篇
  1977年   1篇
  1976年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
群集钙化对鉴别乳腺良恶性病变的意义   总被引:2,自引:0,他引:2  
目的评价乳腺钼靶片群集钙化对鉴别乳腺良恶性病变的意义。方法分析76例乳腺X线钼靶片群集钙化病例,全部经手术病理证实,其中,乳腺恶性病变52例,良性病变24例。采用下列4项指标分析上述76例群集钙化的特征并进行良恶性对照研究:a)病灶钙化总数;b)每平方厘米钙化数目(N/S);c)钙化灶的大小、形态;d)钙化灶合并肿块。结果76例群集钙化病例中钙化总数大于30个、N/S大于等于10个、钙化灶大小形态不一致、钙化合并肿块,这4项指标诊断恶性钙化的特异性和敏感性分别为83.3%和69.2%,79.2%和76.9%,62.5%和92.3%,62.5%和53.8%。结论N/S大于等于10个、钙化总数大于30个及钙化灶大小、形态不一致这3个特征对恶性钙化最具有诊断价值。  相似文献   
152.
目的:探讨硬化注射法治疗直肠前突的有效性。方法:将80例中度及中度以上的直肠前突患者随机分成两组,各40例。试验组行硬化注射法治疗,对照组行经阴道切开修补,并观察两组的治疗效果及并发症。结果:治疗后患者症状评分较治疗前降低,两组治疗效果相比无统计学差异。但治疗组在术中出血、术后疼痛等并发症方面则优于对照组。结论:硬化注射法是一种简便有效的治疗直肠前突的方法。  相似文献   
153.
OBJECTIVE: To evaluate the possibility and reliability of the hyoid-sternohyoid graft transfer in the correction of server subglottic laryngotracheal stenosis, and delineate the operation skills and clinical results. METHODS: Seven patients with severe subglottic stenosis underwent laryngotracheal reconstruction using the hyoid grafts with sternohyoid muscle flaps (HG-SHMF). Five of these patients had traumatic subglottic stenosis, one with scar tissue of unknown etiology arising in the subglottic region, another with tracheal narrowing caused by inhalation of hydrochloric acid. RESULTS: All seven patients were successfully decannulated with moderate good voice. The average time from reconstruction to decannulation was 15.4 months. The stent was endoscopically removed with a range of 3 to 22 months; the mean time required for stenting was 9.6 months. Two patients who received additional salvage reconstruction procedures because of graft or stent displacement were extubated with improved voices and satisfactory airway. CONCLUSIONS: The HG-SHMF transfer was a single-stage reconstruction, relatively simple procedure that can restore an adequate airway and a good voice. Patients undergoing laryngotracheal reconstruction with HG-SHMF must have regular, long-term follow-up since graft displacement and recurrent granulation tissue or scar reformation can cause restenosis after an initially successful surgery. This procedure should be used in a large number of patients to further test its reliability.  相似文献   
154.
内镜活检对胃癌组织学分类术前诊断的价值   总被引:6,自引:0,他引:6  
目的 探讨内镜活检对胃癌组织学分类术前诊断的价值。方法 术前对141例胃癌患的内镜活检标本分别根据Lauren分类和世界卫生组织(WHO)分类判断组织学分类,并与手术标本结果对照。结果 内镜活检对胃癌Lauren分类术前诊断的准确率为76.6%。对肠型胃癌诊断的敏感性和特异性分别为85.4%和80.6%。而对弥漫型胃癌则分别为82.7%和80.3%,在59例术前诊断为肠型胃癌的病例中,18例(30.5%)在手术标本中呈弥漫性行生长,而在75例术前诊断为弥漫型胃癌的病例中,仅6例(8.0%)术后诊断为肠型胃癌,内镜活检对胃癌WHO分类术前诊断的准确率为87.2%,其中对乳头状/管状腺癌,黏液腺癌和印戒细胞癌的敏感性分别为91.9%。33.3%和66.7%。结论 内镜活检对胃癌组织学分类的术前诊断具有较高的临床应用价值。  相似文献   
155.
对某院收治的50名地震伤员进行医院感染目标性监测,有效地预防与控制医院感染的发生。通过分类安置伤员,专人目标监测,严格执行消毒隔离制度及手卫生、标准预防措施等,将医院感染发生率降至最低:仅1例重症挤压伤者发生医院感染,医院感染率为2.00%。  相似文献   
156.
公立医院管理与企业管理的比较分析   总被引:1,自引:0,他引:1  
管理就是制定决策,并不等于企业管理。公立医院除了经营目标不同于企业(前者追求社会效益最大化,后者追求利润最大化)以外,其它方面与企业类似。公立医院要保持公益心,讲求社会效益是其管理的最高目标。  相似文献   
157.
Progressive multifocal leukoencephalopathy (PML) is a fetal demyelinating disease in the central nervous system. PML was once a rare disease, but it is now relatively common among AIDS (acquired immunodeficiency syndrome) patients. The immunological state of patients mainly contributes to the pathogenesis of PML. Genetic changes of the etiological agent, however, may also be involved in the development and progression of the disease. The major genetic changes possibly associated with PML include the regulatory region rearrangement and the VP1 loop mutation. Both changes have been identified as genetic changes usually occurring in JCV (JCvirus) DNAs from the brain and cerebrospinal fluid of PML patients. Although it remained to be clarified how these changes are involved in the pathogenesis of PML, accumulating evidence suggests that the VP1 loop mutation is associated with the progression of PML. Here we overview studies (mainly those performed by ourselves) on these genetic changes.  相似文献   
158.
Transient Macular Edema after Laser In-Situ Keratomileusis   总被引:8,自引:0,他引:8  
Purpose: To investigate the macular changes induced by laser in situ keratomileusisc(LASIK) procedure.Methods: Optical Coherence Tomography (OCT) was used to examine 27 eyes of 15LASIK patients before surgery, and 1 day, 1 week, 1 month after surgery.Results: The mean thick iness of neuroepithelial layer of macula was (195 ±24)microns, (178± 16) microns 1 day and 1 month after surgery, respectively, while thebaseline was (174 ± 12) microns. The increase in macular neuroepithelial thickness wascorrelated with the degree of myopia, but not with the duration of suction or thepostoperative BCVA.Conclusion: Mild macular edema is common in the first month following LASIK,especially in high myopia. However, no association with loss of BCVA has beenestablished. Eye Science 2003; 19: 20 - 24.  相似文献   
159.
K Xiong  P Zheng 《针刺研究》1990,15(1):1-5, 12
This review summarized some articles on the effect of the septal area in acupuncture analgesia. The data showed that the pain threshold of animal was increased when septal area was stimulated by electro-acupuncture, and that electrical stimulation of septal area had a marked inhibitory effect on the pain discharges of cells in parafascicular nucleus of thalamus, lateral habenular nucleus, periaqueductal gray and dorsal raphe nucleus. The septal area play an important role in acupuncture analgesia. The majority of the cholinergic neurons in septal area are located in nucleus of the vertical limb of the diagonal band (VDB); gamma-aminobutyric acid of septal area is mainly found in the diagonal band nucleus(td); Dopamine is present in high levels in td and lateral septal nucleus(S1) of septal area; The S1 contain high densities enkephalin-containing neuronal cell bodies and terminals; In addition, substance P and norepinephrine are also high levels in the septal area. These substance above-mentioned have a relations with acupuncture analgesia of septal area. A large number of serotonin-containing neurons are found in the raphe nuclei. The serotonin play an important role in acupuncture analgesia. The serotonin-containing neurons in dorsal raphe nucleus project to S1. The fiber connections of the raphe nuclei with the td are reciprocation. The periaqueductal gray is a important structure on pain modulation. It projects to septal area and receives the fibers from S1. A number of adrenergic neurons are located within the locus coeruleus. The locus coeruleus participate pain modulation and acupuncture analgesia. The neuro-anatomy study demonstrated that locus coeruleus projects to septal area.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
160.
采用辣根过氧化物酶(HRP)逆行示踪与谷氨酸免疫细胞化学结合法对大鼠额叶和枕叶皮质内胼胝体神经元的化学性质进行了研究.结果发现含谷氨酸的胼胝体神经元为大中型锥体细胞,主要分布于皮质Ⅱ/Ⅲ、Ⅴ和Ⅵ层,并有成群分布的倾向.含谷氨酸的胼胝体神经元的数目约占 HRP 标记的胼胝体神经元的17%(额叶)和29%(枕叶).这一结果从形态学上证实,大鼠大脑皮质内相当一部分胼胝体神经元使用谷氨酸作为兴奋性递质。  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