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   81952篇
  免费   7383篇
  国内免费   5489篇
耳鼻咽喉   846篇
儿科学   884篇
妇产科学   1225篇
基础医学   10584篇
口腔科学   1401篇
临床医学   10907篇
内科学   12321篇
皮肤病学   1026篇
神经病学   4505篇
特种医学   3086篇
外国民族医学   53篇
外科学   8540篇
综合类   10808篇
现状与发展   21篇
一般理论   22篇
预防医学   5125篇
眼科学   2984篇
药学   8504篇
  67篇
中国医学   4203篇
肿瘤学   7712篇
  2024年   271篇
  2023年   1230篇
  2022年   3200篇
  2021年   4130篇
  2020年   3028篇
  2019年   2908篇
  2018年   3080篇
  2017年   2551篇
  2016年   2651篇
  2015年   3807篇
  2014年   4723篇
  2013年   4167篇
  2012年   6176篇
  2011年   6611篇
  2010年   4079篇
  2009年   3085篇
  2008年   4285篇
  2007年   4143篇
  2006年   4250篇
  2005年   4081篇
  2004年   2772篇
  2003年   2536篇
  2002年   2083篇
  2001年   1787篇
  2000年   1773篇
  1999年   2053篇
  1998年   1295篇
  1997年   1266篇
  1996年   957篇
  1995年   904篇
  1994年   765篇
  1993年   481篇
  1992年   593篇
  1991年   497篇
  1990年   471篇
  1989年   411篇
  1988年   370篇
  1987年   300篇
  1986年   249篇
  1985年   210篇
  1984年   130篇
  1983年   86篇
  1982年   42篇
  1981年   51篇
  1980年   29篇
  1979年   63篇
  1978年   22篇
  1974年   27篇
  1973年   18篇
  1968年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
可切除原发性十二指肠恶性肿瘤X线征象分析   总被引:2,自引:0,他引:2  
目的 :对可切除的原发性十二指肠恶性肿瘤X线征象进行分析。方法 :对 2 6例原发性十二指肠恶性肿瘤胃肠道造影及CT征象进行了回顾性对比分析总结。结果 :全部病例均经手术病理证实 ,其中腺癌 2 2例 ,平滑肌肉瘤 3例 ,非何杰金氏淋巴瘤 1例。描述包括肿瘤的部位 ,造影X线表现 (黏膜破坏 ,充盈缺损及龛影 ,管腔不规则狭窄 ,肠腔外改变等 )及CT表现 (肠壁增厚肠腔狭窄 ,局部肿块 ,梗阻性改变及转移 )。不能手术切除的影像学征象为 :肿瘤直径大于 6cm ;腹腔、系膜淋巴结成团肿大 ;腔静脉、肠系膜动静脉等重要血管管径被包绕大于 2 / 3时。结论 :CT与X线造影对肿瘤的位置、大小、形态 ,肿瘤的继发征象的术前评价 ,能够提供能否手术切除的重要依据。  相似文献   
42.
43.
高等医学院校医学化学教材改革的几点思考   总被引:2,自引:1,他引:1  
医学的发展已进入分子水平,医学生必须具有扎实的化学基础才能适应专业学习及临床、科研工作的需要。现行医学化学教材大多沿用几十年前的模式,部分内容陈旧滞后,实用性不强。面对现实,改革势在必行。我们认为,突出重点、注重实用、体现医学特色应作为改革的方向。  相似文献   
44.
Q Chen  P Sun  I Prigione  H Xie  S Ferrini 《Tumori》1992,78(2):79-86
In an attempt to construct bispecific monoclonal antibodies (bimAbs) able to target cytotoxic T lymphocytes against human hepatoma cells, an HGPRT-deficient mutant of the Hepama-6 hybridoma, which produces an antihuman-hepatoma mAb, was directly fused with splenocytes from Balb/C mice immunized by a polyclonal cytotoxic T-cell line. Hybrid hybridomas were selected in HAT medium, and their supernatants were directly screened for the ability to induce IL-2-cultured cytotoxic T lymphocytes to kill hepatoma cells in a 51Cr-release assay. The selected hybrid hybridoma, termed DQ-33, secretes a bimAb, which reacts with a CD3-associated determinant. When resting peripheral-blood lymphocytes were used as effector cells, virtually no cytolytic activity could be induced by DQ-33, whereas phytohemagglutinin-activated lymphocytes that had been expanded in vitro in IL-2-containing medium could be efficiently targeted against hepatoma cells. Targeting by DQ-33 bimAb was analyzed on different subsets of IL-2-cultured lymphocytes. It was evident that CD+4-8+ TCR alpha/beta+ and CD3+4-8-TCR gamma/delta+ lymphocytes were efficiently induced by bimAb to lyse human hepatoma cells, whereas no induction of cytolysis could be observed when CD3 + 4 + 8-TCR alpha/beta+ cells were used as effectors. DQ-33 bimAb was also able to induce lymphokine secretion (IL-2, GM-CSF and TNF-alpha) by all the different subsets of lymphocytes analyzed in the presence of target cells expressing the relevant antigen, independent of the expression of cytolytic activity.  相似文献   
45.
维胺酯-β-环糊精包合物的研究   总被引:6,自引:0,他引:6  
应用3因素8水平的均匀设计方法,优化出维胺酯-β-环糊精包合物最佳制备条件,所得包合物的包合率为99.3%,其表观稳定常数为1394M-1.  相似文献   
46.
Summary To investigate the distribution of possible novel mutations from parkin gene in variant subset of patients with Parkinson’s disease (PD) in China and explore whether parkin gene plays an important role in the pathogenesis of PD, 70 patients were divided into early-onset group and late-onset group; 70 healthy subjects were included as controls. Genomic DNA from 70 normal controls and from those of PD patients were extracted from peripheral blood leukocytes by using standard procedures. Mutations of parkin gene (exon 1–12) in all the subjects were screened by PCR-single strand conformation polymorphism (SSCP), and further sequencing was performed in the samples with abnormal SSCP results, in order to confirm the mutation and its location. A new missense mutation Gly284Arg in a patient and 3 abnormal bands in SSCP electrophoresis from samples of another 3 patients were found. All the DNA variants were sourced from the samples of the patients with early-onset PD. It was concluded that Parkin point mutation also partially contributes to the development of early-onset Parkinson’s disease in Chinese. WANG Tao, male, born in 1961, Associate Professor This work was supported by grants from the key program of the special scientific project of Scientific & Technologic Agency of Hubei Province (Serial No. 2001AA308B01) and the Hygienic Research Project of Hygienic Agency of Hubei province (Serial No. WJ 01529).  相似文献   
47.
目的:通过超声热疗配合常规放疗治疗晚期恶性肿瘤的临床研究,评价超声热疗的疗效及与疗效有关的加热参数。材料和方法: 对17 例晚期恶性肿瘤的17 个病灶用常规放疗加超声热疗。放疗用直线加速器外照射,每次2 Gy、周5 次, 总剂量40~70 Gy。热疗在放疗后30 m in 内进行,每周加热1~2 次,每次加温时间 60 m in,6~8 次一疗程。全例病人每次加温时实测肿瘤内温度。结果:在可评价的13例中,CR 23.1% (3/13)、PR 46.2% (6/13)、NC 23.1% (3/13)、PD 7.7% ( 1/13) , 有效率(CR+ PR)为69.3% 。肿瘤中心部温度达到42.5℃以上的累积时间和总加热次数是决定疗效的重要参数。在17 例患者的 89 次加温中,副作用的发生率相对较低。结论:使用超声热疗配合放疗,只要实现满负荷加温,进一步提高肿瘤的局部控制率是完全可能的  相似文献   
48.
Summary. Between 1982 and 1991 we treated 48 patients with a glomus tumour in the hand or foot. There were 42 women and 6 men, aged between 14 and 61 years. Forty-five tumours were in the subungual region and 41 were on the anterolateral aspect of a distal phalanx. The lesions presented with a classic triad of pain, tenderness and sensitivity to temperature, particularly cold. Excision of the tumour was curative.
Resumé. Entre 1982 et 1991, 48 patients présentant une tumeur glomique de la main et du pied ont été traités dans notre département. Il y avait 42 femmes et 6 hommes, agés de 14 à 61 ans (moyenne 38 ans). 45 tumeurs étaient en situation sous-inguéale et 41 en situation latéro-palmaire de la phalange distale. 44 se situaient au niveau de la main et 4 au niveau du gros orteil. Ces lésions sont souvent non palpables fréquemment invisibles et habituellement indétectables à la radiographie. Cependant, le diagnostic est assez facile, lorsqu’existe la triade symptomatique: douleur, tumefaction molle et sensibilité au froid. L’excision complète après dissection soigneuse est le traitement adéquate. Le suivi des 48 malades a toujours montré une guérison complète.


Accepted: 21 May 1996  相似文献   
49.
J Sun 《中华心血管病杂志》1991,19(6):375-7, 398
The hemodynamic changes of 15 cases during external counterpulsation with left and right cardiac catheters were reported. The results showed that the diastolic pressure at the root of the aorta was remarkably increased, the peak value (countercurrent pressure) was 8.02 +/- 2.05 kPa higher than the diastolic pressure before counterpulsation; the aortic systolic pressure during counterpulsation was slightly decreased with a mean value of 0.81 kPa; there was no apparent change in the central venous pressure and pulmonary arterial pressure; pulmonary arterial wedge pressure was slightly reduced during counterpulsation. All the above data are useful in showing the improvement of cardiac and brain perfusion volume and clarifying its mechanism.  相似文献   
50.
Oligonol is produced from the oligomerization of polyphenols (typically proanthocyanidin from a variety of fruits such as lychees, grapes, apples, persimmons, etc.) and contains catechin-type monomers and oligomers of proanthocyanidins. The ability of Oligonol to affect infection-dependent eye inflammation, locomotion and longevity in senescence-accelerated prone mice (SAMP8) (a model of senescence acceleration and geriatric disorders with increased oxidative stress and neuronal deficit) was investigated. Oligonol (60mg/kg) significantly modulated the extent of inflammation scores in the eye of SAMP8 mice. Examination of the mice indicated infection with mouse hepatitis virus and pinworm (Syphacia obvelata) in both males and females and with the intestinal protozoa (trichomonad) in males. A comparison of the two groups (using log-rank test) and the difference in the mean life span between groups (using Student's t-test) indicated significant differences in survival (p=0.043) and the mean life span (p=0.033) in male SAMP8 mice. Oligonol increased the mean life span and this was statistically significant. In the open-field locomotive test, the 7-week-old SAMP8 mice crossed more than 40 partitioned lines in 1min. At 48-week-old control untreated male SAMP8 crossed 2 lines. The Oligonol-treated 48-week-old male SAMP8 mice crossed 17 lines however. The improved locomotive activity was statistically significant even after 36weeks in the Oligonol-treated male SAMP8 but this was not the case throughout the time course of the study in the Oligonol-treated female SAMP8. Thus Oligonol treatment to SAMP8 mice modulated the severity of infection-dependent inflammation, prolonged life-span and significantly improved locomotive activity indicating potential benefit to aging-associated diseases such as Alzheimer's or Parkinson's diseases. This presents potential for further research to define infection-dependent inflammation associated with degenerative conditions and the molecular mechanism of dietary antioxidant protection.  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