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   17985篇
  免费   1140篇
  国内免费   391篇
耳鼻咽喉   307篇
儿科学   500篇
妇产科学   884篇
基础医学   2269篇
口腔科学   1083篇
临床医学   1737篇
内科学   1518篇
皮肤病学   123篇
神经病学   2578篇
特种医学   560篇
外国民族医学   1篇
外科学   2012篇
综合类   2353篇
预防医学   703篇
眼科学   306篇
药学   1603篇
  5篇
中国医学   583篇
肿瘤学   391篇
  2024年   36篇
  2023年   230篇
  2022年   464篇
  2021年   629篇
  2020年   570篇
  2019年   531篇
  2018年   524篇
  2017年   501篇
  2016年   540篇
  2015年   594篇
  2014年   901篇
  2013年   1094篇
  2012年   868篇
  2011年   1028篇
  2010年   857篇
  2009年   813篇
  2008年   781篇
  2007年   755篇
  2006年   749篇
  2005年   660篇
  2004年   588篇
  2003年   489篇
  2002年   401篇
  2001年   367篇
  2000年   345篇
  1999年   314篇
  1998年   281篇
  1997年   280篇
  1996年   292篇
  1995年   291篇
  1994年   287篇
  1993年   220篇
  1992年   206篇
  1991年   191篇
  1990年   174篇
  1989年   149篇
  1988年   164篇
  1987年   136篇
  1986年   141篇
  1985年   197篇
  1984年   158篇
  1983年   110篇
  1982年   140篇
  1981年   121篇
  1980年   80篇
  1979年   65篇
  1978年   77篇
  1977年   41篇
  1976年   26篇
  1973年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Endometriosis and infertility are commonly associated. Thisstudy investigated the role of accelerated lipid peroxidationof spermatozoa by the peritoneal fluid of patients with endometriosisas a cause for this association. It proposes that the increasediron concentration present in the fluid of these patients actsas a catalyst for the process. Peritoneal fluid from 25 patientswith endometriosis and 25 matched controls was obtained at laparoscopy.Spermatozoa were incubated in the fluid from both groups andthe subsequent acrosome reaction rates analysed. The relationshipbetween these results and iron concentration in the fluid wasexamined. A significant decrease in the acrosome reaction ratewas seen in the endometriotic group(P = 0.034). Overall, a decreasein the acrosome reaction rate was associated with an increasediron concentration in the fluid(18 of the 25 pairs). In milddisease, (six of 11 pairs), the relationship was not as markedas that in severe disease (12 of 14 pairs). These results suggestthat the peritoneal fluid in patients with endometriosis hasa detrimental action on the acrosome reaction of spermatozoain vitro.  相似文献   
82.
The effect of acute and sequential volaemic changes on the gastroduodenal flow of saline was assessed in 23 anaesthetized dogs following two different experimental protocols. Hypervolaemia, by i. v. infusion of saline, induced a gradual decrease on gastroduodenal flow which amounted to 76% below control values (P < 0.001) when volaemic expansion attained 5% of body weight. This effect was volume dependent (17% increase on gastroduodenal flow per volume of infused saline equivalent to 0.5% of body weight, P < 0.001), lasted for at least 90 minutes after infusion was completed and was also obtained by expanding previously bled animals. Hypovolaemia due to bleeding was followed by an increase on gastroduodenal flow of about 88% above control values (P < 0.05) when haemorrhage was equal to 3% of body weight. This effect was also volume dependent (23 % increase on gastroduodenal flow per volume of blood shed equivalent to a 0.5% of body weight, P < 0.01) and was reversed after blood volume was restored. These modifications in the resistance of the gastroduodenal segment to the flow of liquid due to acute volaemic changes suggest that the extracellular fluid volume modulates the contractile activity of the gastroduodenal portion of the gut possibly to set a gastroduodenal handling of liquid adequate to cope with volaemic imbalances.  相似文献   
83.
对牙周健康者和龈炎、牙周炎患者25人共130个牙位的龈沟液(GCF)中硷性磷酸酶(ALP)活性进行了检测。GCP-ALP活性(u/uL或u/牙)在炎症牙位和健康牙位间有显著差别,与牙龈指数(GI)和附着丧失(AL)呈正相关性。炎症牙位经牙周综合治疗6周后,其GCF-ALP活性显著降低。说明GCP-ALP水平能反映出牙周组织炎症的进展情况。  相似文献   
84.
Ten patients with subhepatic fluid collections complicating laparoscopic Cholecystectomy were successfully treated by interventional radiological procedures. The series included five abscesses, three hematomas, one biloma, and one serous collection. Abdominal pain or fever developed from 3 to 21 days after the laparoscopic intervention. All patients were asymptomatic 72 h after percutaneous drainage and there were no complications related to the procedure. Subhepatic fluid accumulations are common findings after laparoscopic cholecystectomies and have been considered an unreliable indicator of infection or other postoperative complications. However, the significance of these collections should not be underestimated in symptomatic patients. In such cases we propose diagnostic aspiration and drainage, when necessary, to safely and promptly establish the precise diagnosis and treatment. More serious complications can be avoided by early percutaneous intervention.  相似文献   
85.
鼻内窥镜诊治脑脊液漏的临床研究   总被引:1,自引:0,他引:1  
目的 探讨鼻内窥镜手术治疗脑脊液鼻漏临床相关因素。方法 对17例(19漏)内窥镜下修补脑脊液鼻漏患者的临床资料作回顾性分析。结果 脑脊液鼻漏17例中,外伤性15例,自发性2例,内窥镜下瘘口修补术一次性治愈15例,成功率88.2%,失败2例,再次修补成功,其中1例颅内高压术后腰穿持续引流减压。结论 内窥镜手术修补脑脊液鼻漏准确、微创;冠位CT薄层扫描对术前瘘口解剖定位有重要意义;影响手术效果的因素与修补材料的固定有关,与修补材料本身无明显关系;术后适当腰穿引流对于临床提示颅内压高、修补区薄弱病例仍需采用。  相似文献   
86.
目的 观察白术桃花汤治疗习惯性便秘的疗效。方法 自拟白术桃花汤 (白术 30g ,桃花 12g ,生地黄 30g ,枳实 10g) ,每日服 1剂 ,7d为 1个疗程。对照组服用果导片作对比观察。结果 白术桃花汤治疗习惯性便秘 117例 ,治愈 10 6例 ,好转 4例 ,总有效率 94 .0 2 %;果导片治疗 6 6例 ,治愈18例 ,好转 30例 ,总有效率 72 .73%。两组总有效率比较 ,经统计学处理P <0 0 1,差异有非常显著性意义。结论 白术桃花汤功能为补气除湿 ,增液行气 ,通调大便 ,治疗习惯性便秘疗效满意。  相似文献   
87.
Laboratory of General Pathology of the Nervous System, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Department of Pathological Physiology, N. I. Pirogov Odessa Medical Institute. Translated from Byulleten' Éksprimental'noi Biologii i Meditsiny, Vol. 106, No. 8, pp. 146–149, August, 1988.  相似文献   
88.
Abstract: The vitamin B12 (VB12) parameter was studied in the serum and cerebrospinal fluid (CSF) of 14 demented patients. Eleven of these patients were in a state of dementia of the degenerative type such as Alzheimer's disease, senile dementia and Pick's disease. The serum VB12 concentration in all the patients was within normal limits, I.e. 500–1,300 pg/ml. There was no significant difference between the CSF-VBl2 levels and the severity of dementia. The serum and CSF-VB12 levels of the demented patients did not show any significant elevation after the oral administration of CH3–Bl2, 2 mg per day. On the other hand, there was a marked elevation of both the serum and CSF-VB12 after an oral medication (2 mg per day) plus intramuscular administrations (500 μg per day). These results confirm that the intramuscular administration of CH3–B12 is an effective way to get a higher value of the serum and CSF-VB12 levels.  相似文献   
89.
目的研究人胎盘组织液的主要药效作用。方法建立二甲苯所致小鼠耳肿胀及大鼠棉球肉芽肿的药理模型,观察人胎盘组织液对炎症模型动物的抗炎作用。结果与模型对照组相比,连续7d肌肉注射0.1mL/kg剂量的人胎盘组织液对二甲苯所致小鼠耳肿胀起到明显抑制作用,且差异显著(P〈0.01);连续6d肌肉注射0.1mL/kg剂量的人胎盘组织液对大鼠棉球肉芽组织增生起到明显抑制作用,且差异显著(P〈0.01)。结论人胎盘组织液具有明显的抗炎作用。  相似文献   
90.
目的 观察脑脊液中右旋布洛芬浓度随时间变化的情况。方法 新西兰家兔脑部直接注射右旋布洛芬 ,用高效液相色谱法测定其浓度。色谱条件 :KromasilC18(15 0mm× 4 .6mm ,7μm)色谱柱 ,流动相为甲醇∶0 .0 2mmol/L磷酸二氢钾∶乙腈 (6 5∶30∶5 ) ,流速 1.0ml/min ,柱温为室温 ,检测波长 2 2 5nm ,以保泰松为内标。结果 脑脊液右旋布洛芬在 0 .5~ 80 μg/ml范围内线性关系良好 ,r =0 .9994。药物在脑脊液中Tmax为 1.1h ,Cmax为 9.9μg/ml,T1/ 2 为 3.5h ,AUC为 6 1.0 μg·h/ml。结论 HPLC RP法可用于测定脑脊液中右旋布洛芬含量 ,药物在脑脊液中代谢呈一室模型。  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