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   94250篇
  免费   8904篇
  国内免费   4933篇
耳鼻咽喉   1293篇
儿科学   2811篇
妇产科学   1464篇
基础医学   8024篇
口腔科学   2653篇
临床医学   10606篇
内科学   12837篇
皮肤病学   1301篇
神经病学   4924篇
特种医学   4103篇
外国民族医学   27篇
外科学   11764篇
综合类   15935篇
现状与发展   13篇
一般理论   10篇
预防医学   7037篇
眼科学   2615篇
药学   9187篇
  55篇
中国医学   5820篇
肿瘤学   5608篇
  2024年   335篇
  2023年   1406篇
  2022年   2995篇
  2021年   4089篇
  2020年   3300篇
  2019年   2734篇
  2018年   3339篇
  2017年   3342篇
  2016年   3166篇
  2015年   3958篇
  2014年   5217篇
  2013年   5843篇
  2012年   7732篇
  2011年   7964篇
  2010年   5996篇
  2009年   4865篇
  2008年   5729篇
  2007年   5602篇
  2006年   5392篇
  2005年   4914篇
  2004年   4471篇
  2003年   3880篇
  2002年   2997篇
  2001年   2204篇
  2000年   1813篇
  1999年   1272篇
  1998年   620篇
  1997年   654篇
  1996年   478篇
  1995年   365篇
  1994年   341篇
  1993年   205篇
  1992年   150篇
  1991年   142篇
  1990年   127篇
  1989年   98篇
  1988年   87篇
  1987年   74篇
  1986年   59篇
  1985年   28篇
  1984年   21篇
  1983年   23篇
  1982年   8篇
  1981年   8篇
  1980年   4篇
  1979年   5篇
  1978年   4篇
  1974年   5篇
  1972年   5篇
  1963年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
上海社区老年人用药安全及影响因素分析   总被引:11,自引:0,他引:11  
目的:了解上海社区老年人群的用药安全情况及其影响因素,方法:以整群抽样的方法抽取上海市黄浦区两个居民委员会2985名60岁以上的居民进行问卷调查,了解其疾病和用药情况,用药反应,对安全用药的知识,态度,行为,以及影响其用药行为的因素,结果:被调查中高血压、冠心病、消化系统疾病和呼吸系统疾病的患病率分别为35.93%、10.67%、5.70%和3.71%。抗高血压药,心脑血管病药,消化系统疾病和呼吸系统疾病的患病率分别为35.93%、10.67%、5.70%和3.71%,抗高血压药、心脑血管病药,消化系统药和抗生素的使用率分别为31.72%、16.20%、2.43%和2.11%,过去30天内,51.33%的被调查用过药物,用药不良反应发生率为2.06%,对用药安全的正确知识,态度,行为率分别为71.62%、69.39%及60.67%,影响药物选择的因素中医生占88.19%,结论:老年人的用药安全仍存在问题,有待改进,医生是影响老年人药选择的最主要因素。  相似文献   
92.
Since it covers the lateral wall of the mastoid air system, the suprameatal triangle is of importance to otologic surgeons during mastoidectomy. Because of this clinical importance, topographic anatomy of the suprameatal spine and depression was studied on Anatolian skulls. In all, 363 male and 231 female skulls were studied. The most prevalent type of suprameatal spine resembled a crest and was found in both sexes on the right (77.6%) and left (80%) sides. The absence of a suprameatal depression was significantly higher in females (right 9.1%; left 8.7%) than in males (right 1.7%; left 2.5%). Suprameatal depressions were mostly shallow in female subjects, but were mostly observed in males to be at a medium depth or deep. Received: 5 January 1998 / Accepted: 19 March 1998  相似文献   
93.
来用锁相环IC CD4046设计的心率显示报警电路,用于数台老式监护仪的改造中,获得成功.  相似文献   
94.
We report a fluid level in an acute extradural haematoma developing after placement of a ventriculoperitoneal shunt for hydrocephalus. This fluid level was thought to be due to a mixture of blood and cerebrospinal fluid.  相似文献   
95.
Objective Pretargeting with radioactivity has significantly improved tumor to normal tissue radioactivity ratios over conventional antibody imaging in both animal studies and clinical trials. This laboratory is investigating DNA analogues such as phosphorodiamidate morpholinos (MORFs) for pretargeting using technetium-99m (99mTc) for detection. However, the unique properties of fluorescence activation and quenching combined with oligomers with their unique properties of hybridization may be particularly useful when used together for pretargeting with optical detection. The use of linear fluorophore-conjugated oligomer duplexes have been little used in animals, and to our knowledge, have not previously been considered for pretargeting applications. Methods A MORF/cDNA pair was selected such that when hybridized, the fluorescence of the Cy5.5-conjugated 25 mer MORF (Cy5.5–MORF25) is inhibited with a BHQ3-conjugated 18 mer complementary DNA (BHQ3–cDNA18). The short BHQ3–cDNA18 was selected to dissociate in the presence of a long cMORF25 in the pretargeted tumor, thus releasing the inhibitor from the Cy5.5 emitter. In this manner, the Cy5.5 fluorescence will be inhibited everywhere but in the target. The dissociation was first examined in vitro by adding the duplex to the cMORF25 both in solution and immobilized on polystyrene microspheres and by surface plasmon resonance (SPR). Thereafter, biotinylated cMORF25 immobilized on streptavidin polystyrene microspheres were administered intramuscularly in one thigh of hairless SKH-1 mice as target while an identical weight of the identical microspheres but without the cMORF25 was administered in the contralateral thigh as control. The animals then received IV the Cy5.5–MORF25/BHQ3–cDNA18 duplex or equal molar dosage of single-chain Cy5.5–MORF25 and were imaged. Results The SPR studies showed that the immobilized cDNA18 rapidly captured the flowing MORF25 to provide a duplex with a slow dissociation rate constant. Furthermore, when cMORF25 was next allowed to flow over the now immobilized duplex, the cDNA18 was unable to prevent dissociation of the heteroduplex and the formation and release of the cMORF25-MORF25 homoduplex. Images of animals obtained soon after receiving the Cy5.5–MORF25 singlet showed intense whole body fluorescence obscuring the target thigh. However, only 5 minutes after receiving the Cy5.5–MORF25/BHQ3–cDNA18 duplex, the target thigh was clearly visible along with only the kidneys. Conclusions This first study of optical pretargeting provides a proof of concept that oligomer pretargeting found to be useful with radioactivity detection is applicable with fluorescent detection as well. In addition, our results demonstrate that by using linear oligomers for optical pretargeting, chain lengths (and base sequences) may be manipulated to provide duplexes with stabilities and fluorescence inhibition optimized for pretargeting and other in vivo applications of optical imaging.  相似文献   
96.
97.
江汉平原鼠间流行性出血热感染研究   总被引:4,自引:0,他引:4  
为了解湖北省江汉平原流行性出血热(EHF)疫区鼠间感染状况,采用挖洞法捕鼠,鉴定鼠种、性别和年龄,检查有无皮肤破伤,检测EHFV抗原抗体。结果,黑线姬鼠和褐家鼠占所捕鼠的69.7%和23.6%,其EHFV感染率分别为21.8%和30.9%。鼠间EHFV感染,成年鼠显著高于亚成年鼠和幼年鼠,感染率分别为40.8%、17.0%和12.4%;皮肤破伤鼠感染率45.9%,显著高于非皮肤破伤鼠的13.9%。感染鼠以窝为单位具有明显的窝聚集性,而感染鼠窝在地理空间上则随机分布。感染鼠血清分型,黑线姬鼠以野鼠型为主,少数为未定型;褐家鼠以家鼠型为主,亦有少数未定型。这表明,江汉平原EHF疫区是以黑线姬鼠和褐家鼠为主要宿主动物的家野混合型疫区;年龄、皮肤破伤和密切接触是该疫区鼠间EHFV传播的重要因素。  相似文献   
98.
99.
通过经口投给100ppm氯化镉与不投给镉的两组Wistar雄性大鼠研究镉对大鼠肠粘膜中三价运铁蛋白形成的影响。结果表明,镉可降低脏器中贮藏铁的含量,可阻止铁进入肠全粘膜中,镉引起动物铁不足与其枯膜中铁蛋白及其它未知蛋白结合的关系应给以重新评价,而在体外试验中,即使给于高浓度氯化镉,对前运铁蛋白转为运铁蛋白也仅仅表现轻微的抑制作用。  相似文献   
100.
脾动脉栓塞治疗外伤性脾破裂28例临床疗效观察   总被引:3,自引:0,他引:3  
王佾 《中国综合临床》2002,18(8):729-730
目的:探讨脾动脉栓塞术对外伤性脾破裂的疗效及并发症的处理。方法:采用Seldinger法行脾动脉栓塞术治疗外伤性脾破裂28例。结果:所有患者出血立即停止,其中4例行2次栓塞。28例均有脾区疼痛,22例发热。脾动脉栓塞5天后血小板、白细胞上升近1倍,7天后恢复至正常范围。28例随访6-36月,查免疫球蛋白、CT等结果满意,未有再出血及发生暴发性感染。结论:脾动脉栓塞不但有良好的止血作用,而且能保留脾脏的免疫功能,可在非手术治疗失败时选用,是外伤性脾破裂的一种有效治疗方法。  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