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   285636篇
  免费   26145篇
  国内免费   17168篇
耳鼻咽喉   2889篇
儿科学   4096篇
妇产科学   4215篇
基础医学   27661篇
口腔科学   5396篇
临床医学   35178篇
内科学   39153篇
皮肤病学   3414篇
神经病学   12497篇
特种医学   10119篇
外国民族医学   106篇
外科学   29352篇
综合类   53738篇
现状与发展   68篇
一般理论   28篇
预防医学   22979篇
眼科学   6909篇
药学   30205篇
  299篇
中国医学   18824篇
肿瘤学   21823篇
  2024年   957篇
  2023年   3856篇
  2022年   9606篇
  2021年   12664篇
  2020年   9908篇
  2019年   8029篇
  2018年   8679篇
  2017年   8610篇
  2016年   7881篇
  2015年   12577篇
  2014年   15650篇
  2013年   16322篇
  2012年   23725篇
  2011年   25523篇
  2010年   18623篇
  2009年   15491篇
  2008年   18231篇
  2007年   17749篇
  2006年   16695篇
  2005年   14630篇
  2004年   10449篇
  2003年   9697篇
  2002年   8027篇
  2001年   6411篇
  2000年   5405篇
  1999年   4598篇
  1998年   2429篇
  1997年   2293篇
  1996年   1823篇
  1995年   1701篇
  1994年   1464篇
  1993年   871篇
  1992年   1276篇
  1991年   1110篇
  1990年   955篇
  1989年   786篇
  1988年   713篇
  1987年   640篇
  1986年   496篇
  1985年   389篇
  1984年   240篇
  1983年   211篇
  1982年   128篇
  1981年   131篇
  1979年   181篇
  1978年   128篇
  1977年   102篇
  1974年   116篇
  1973年   100篇
  1972年   96篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
报告8例Wegener肉芽肿病。本组疾病的病理特点均表现为坏死性血管炎及肉芽形成。临床特点为:发热(38-40℃)、鼻塞、鼻衄、咳嗽、口腔及鼻咽部溃疡,皮下结节:X线表现为肺部多发性结节及空洞阴影,副鼻窦炎症。尿常规检查异常,诊断主要依靠病变组织活检。环磷酰胺和肾上腺皮质激素联合治疗效果显著。  相似文献   
52.
MK-679 (R(?)-3-((3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)(3-(dimethylamino)-3-oxopropyl)thio)methyl)thio(propanoic acid) is a potent and specific LTD4-receptor antagonist. The disposition of MK-679 was investigated in a three-way crossover study in 12 healthy males receiving single intravenous doses of 75, 250, and 500 mg of MK-679. A greater than proportional increase in the area under the plasma concentration—time curve of MK-679 was observed with increase in dose. The plasma concentration data for each subject fitted well to the differential equations for a two-compartment model with linear tissue distribution and Michaelis-Menten elimination from the central compartment, indicating that the elimination of MK-679 in humans is saturable. In a previous study, the disposition of MK-679 in humans was also dose-dependent when given together with its S(+)-isomer, L-668,018. Thus, the disposition of MK-679 in humans is dose-dependent regardless of the presence of its stereoisomer. Also, the bioavailability of MK-679 was determined in six healthy males receiving simultaneously an oral dose of 250 mg of MK-679 and intravenous infusion of 1 mg 14C-MK-679. Results of this study indicate that the oral bioavailability of MK-679 is nearly quantitative.  相似文献   
53.
Clinically significant contact lens induced corneal warpage is seen in a small proportion of soft and rigid contact lens wearers. Previous studies using the keratometer have found no correlation between the fit of the lens and the induced topographic changes. In this study, using computer-assisted topographic analysis, seven eyes (four patients) with rigid contact lens-induced corneal warpage were noted to have topographic abnormalities that correlated with the decentered resting position of the contact lens on the cornea. The warpage topography for each of these corneas was characterized by a relative flattening of the cornea underlying the resting position of the contact lens. Lenses that rode high, for example, produced flattening superiorly and resulted in a relatively steeper contour inferiorly that simulated the topography of early keratoconus patients who had not worn contact lenses. After discontinuing contact lenses the corneal topography returned to a normal pattern in five eyes. Two eyes retained asymmetry that is not characteristic of normal corneas. Up to 6 months was required for the corneas to return to a stable topography after contact lens wear was discontinued.  相似文献   
54.
分别采用联合火箭免疫电泳技术和酶法对49例冠心病患者和50例健康人血清载脂蛋白 A_1(apoA_1),载脂蛋白 B_(100)(apoB_(100)),以及血清总胆固醇(TC)、甘油三酯(TG),高密度脂蛋白胆固醇(HDL—ch)的含量进行了测定。结果冠心病患者血清 apoB_(100)(0.99±0.26g/L)明显高于健康人(0.62±0.18g/L);而apoA_1/apoB_(100)比值(1.22±0.35)则明显低于健康人(2.12±0.49);TC,TG,HDL-ch 的含量亦有统计学意义。提示,在预示冠心病危险因素的各种脂类及脂蛋白中,以 apoB_(100)增高 apoA_1/apoB_(100)比值降低最为灵敏,最为准确,且高于单纯测定TC,TG 和 HDL-ch。  相似文献   
55.
56.
Fifty-one patients who had persistent or recurrent neck disease from nasopharyngeal carcinoma after radiotherapy underwent radical neck dissection. The follow-up period ranged from 0.5 to 9 years (median: 2 years). Multiple cervical lymph node involvement was present in 51% of the patients (26 of 51). Malignant cells were detected in 88% of the resected specimens (45 of 51). The clinical sign of fixation of lymph node is the only factor that affects the successful control of neck disease (p = 0.04). Extracapsular extension of the nodal disease was present, and 35% of the lymph nodes were adherent to surrounding structures at operation (18 of 51). There was one hospital mortality and the overall morbidity was minimal. The actuarial survival at 5 years was 38%, and the probability of control of neck disease was 66%. Radical neck dissection is effective in controlling post-irradiation cervical metastasis from nasopharyngeal carcinoma.  相似文献   
57.
58.
Elevation of prostaglandins and protein in the aqueous humor is an immediate response to Yag-laser anterior capsulotomy. There was a significant correlation between prostaglandins and thromboxane to the elevation of intraocular pressure. The elevation of protein concentration was proportional to the elevation of prostaglandin F1, but not to thromboxane. The biochemical changes in the aqueous humor were more severe as laser power was increased above 3 mj. While the role of prostaglandins in the elevation of intraocular pressure is uncertain, the present data recommend the selection of laser power below 3 mj to avoid pressure rise instead of inhibition of all prostaglandin synthesis by medication.  相似文献   
59.
MRI同层动态增强对垂体微腺瘤的诊断价值   总被引:3,自引:0,他引:3  
目的:分析垂体微腺瘤的MPd同层动态增强特征。方法:对40例临床怀疑为垂体微腺瘤的病人行同层动态增强MPd扫描,并绘出时间一信号强度曲线图。结果:40例病人中共检出垂体微腺瘤26例。同层动态增强后垂体微腺瘤的MPd表现为圆或椭圆形的低或稍低信号,似“充盈缺损”;垂体微腺瘤的最大信号强度多出现在注入造影剂后32~96s,以64s最明显。结论:同层MPd动态增强对垂体微腺瘤的诊断有较高价值。  相似文献   
60.
结肠癌伴糖尿病病人的围手术期护理   总被引:2,自引:0,他引:2  
[目的]探讨结肠癌伴糖尿病围手术期的最佳护理措施。[方法]对41例患有糖尿病的结肠癌围手术期病人,采取术前心理护理、控制血糖、清洁肠道、术后安置合适体位、加强引流管护理、积极预防并发症、良好的营养支持。针对易发生感染性并发症的特点,加强对呼吸道、皮肤、泌尿系、伤口感染预防的护理。[结果]发生与感染有关的并发症5例,其中肺部感染2例、切口感染2例、尿路感染1例。[结论]通过以上方法护理,使围手术期并发症明显减少,而且方法简便易行,容易做到。  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