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   8052篇
  免费   569篇
  国内免费   135篇
耳鼻咽喉   21篇
儿科学   139篇
妇产科学   42篇
基础医学   496篇
口腔科学   63篇
临床医学   1052篇
内科学   2684篇
皮肤病学   29篇
神经病学   179篇
特种医学   611篇
外科学   902篇
综合类   716篇
预防医学   472篇
眼科学   25篇
药学   634篇
  2篇
中国医学   427篇
肿瘤学   262篇
  2024年   21篇
  2023年   256篇
  2022年   437篇
  2021年   576篇
  2020年   460篇
  2019年   541篇
  2018年   494篇
  2017年   265篇
  2016年   232篇
  2015年   272篇
  2014年   562篇
  2013年   459篇
  2012年   380篇
  2011年   409篇
  2010年   286篇
  2009年   285篇
  2008年   314篇
  2007年   353篇
  2006年   232篇
  2005年   204篇
  2004年   153篇
  2003年   137篇
  2002年   106篇
  2001年   127篇
  2000年   81篇
  1999年   92篇
  1998年   89篇
  1997年   91篇
  1996年   60篇
  1995年   70篇
  1994年   68篇
  1993年   49篇
  1992年   60篇
  1991年   60篇
  1990年   44篇
  1989年   40篇
  1988年   45篇
  1987年   41篇
  1986年   33篇
  1985年   40篇
  1984年   42篇
  1983年   30篇
  1982年   32篇
  1981年   25篇
  1980年   15篇
  1979年   14篇
  1977年   12篇
  1976年   11篇
  1975年   10篇
  1973年   9篇
排序方式: 共有8756条查询结果,搜索用时 15 毫秒
71.
Gm allotypes in blacks with systemic lupus erythematosus   总被引:3,自引:0,他引:3  
Serum samples were collected from 328 healthy American Blacks and from 61 American Blacks with systemic lupus erythematosus (SLE). Sera were typed for the Gm1,2,3,5,6,13,17, and 21 allotypes as well as for the Km(1) allotype. The frequency of Gm phenotype 1,17;5,6,13 was significantly increased in the SLE patients (p = 0.0001, RR = 3.19, EF = 0.29). Our data suggest the existence of at least two immunoglobulin allotype associated genes that somehow interact to increase susceptibility to SLE in Blacks. To our knowledge, this is the first report of an association of Gm and SLE in Blacks.  相似文献   
72.
Summary During incremental exercise, the left ventricular ejection fraction increases up to the intensity of the anaerobic threshold and tends to level off at higher exercise intensities. Since there is a correlation between the response of peak filling rate and ejection fraction to exercise, this study was conducted to determine whether the response of left ventricular diastolic function is similar to the response of systolic function relative to lactate threshold. Twelve healthy men performed two exercise tests on a cycle ergometer. In the first test, lactate threshold and maximal power output were determined. In the second exercise test, gated radionuclide ventriculography was performed at rest, at the lactate threshold intensity, and at peak exercise to measure ejection fraction and peak filling rate. Ejection fraction increased significantly from rest [mean (SD): 62 (5)%] to lactate threshold [76 (7) %] and did not change significantly from lactate threshold to peak exercise [77 (7)%]. Likewise, peak filling rate (normalized for stroke counts) increased from resting [6.1 (0.9)V s · s–1] to lactate threshold [9.4 (1.8)V s · s–1] and did not change significantly from lactate threshold to peak exercise [9.6 (2.9)V s · s–1]. There was no correlation between the change in peak filling rate and the change in ejection fraction from rest to lactate threshold. Thus, during incremental exercise, left ventricular diastolic function responds qualitatively similar to systolic function.  相似文献   
73.
To investigate airway physiology by use of inhaled aerosols, it is frequently necessary to measure the actual amount of material deposited on the airway wall as well as the site of particle deposition. To satisfy these needs, radiolabeled aerosols and gamma camera techniques have been used to measure regional deposition of inhaled particles. To make quantitative measurements of the amount deposited, previous investigators have used a "phantom" technique to indirectly calibrate the gamma camera for the attenuation of gamma rays through the lungs and chest wall. For this calibration, the phantom is a simulated lung containing a known amount of radioactivity. Radioactive counts emitted from the phantom are assumed to be attenuated in the same manner as the intact human lung. The present article describes a technique to determine directly the amount of inhaled aerosol deposited in the lung and simultaneously to calibrate the gamma camera for each individual subject. We used right angle light scattering and a gamma camera to measure individual values of the deposition fraction (DF) of inhaled aerosol deposited in the lung and the coefficient of attenuation (AC) of gamma rays in normal and obstructed lungs of human subjects. Radiolabeled monodisperse aerosols 1 and 2 microns in diameter were used. Knowledge of the activity of the inhaled aerosol (microcurie per liter), the volume inhaled, and the measured DF determined each subject's AC (counts per minute per microcurie). DF varied by an order of magnitude in normal (0.04 to 0.48) and obstructed (0.16 to 0.75) of subjects.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
74.
The effects of macronutrients on appetite and total caloric intake in monkeys (Macaca mulatta) was studied using a new feeding and infusion system which yoked intragastric infusion of various nutrients to oral ad lib intake and removed the confounding factor of palatability from the assessment of nutrient effects on feeding behavior. A suction-activated liquid diet feeding system provided free access to a nutritionally complete diet, with 1 ml of diet delivered orally by pump with each discrete suck by the monkey. A second pump was yoked to the oral feeding pump and delivered various nutrients directly into the stomach via an implanted intragastric cannula. Thus, while oral diet composition remained constant, the net diet reaching the stomach varied over ranges of 28 to 77% carbohydrate, 16 to 65% fat and 7 to 36% protein. No significant differences in total caloric intake were observed between intakes of diets with net composition of high carbohydrate or high fat. When protein was increased to 36%, total caloric intake was generally reduced, and this effect was sustained for at least 3 weeks. Therefore, protein appears to have an increased specific satiating effect beyond the caloric content, when compared to carbohydrate or fat.  相似文献   
75.
The author, a pioneer in originating the technique of suction lipectomy, discusses in detail the pathophysiology of the fat cell and fat metabolism. In addition, he describes the surgical means by which, since 1977, he has popularized this innovative new approach to the treatment of unsightly fat deposits in many sites in the body, including the thighs, buttocks, abdomen, hips, arms, ankles, breasts, and submental regions.  相似文献   
76.
The fat nose     
The fat or sebaceous nose,* with its thick, bulky skin filled with prominent sebaceous glands, is often improved surgically only by the use of external excisions of this tissue. The author describes several variations of this technique with representative cases.  相似文献   
77.
ObjectiveInsufficient and poor-quality sleep among young adults is closely related to obesity and may impact metabolic processes. The mobilization and use of endogenous substrates during sleep, especially fat oxidation, is essential for energy metabolism. This study investigated whether there are differences in sleep structure, metabolic rate, substrate oxidation, and the respiratory quotient (RQ) between young males with normal weight and obesity according to sleep stages and overnight sleep.MethodsFifteen young males with normal weight and fifteen with obesity posited electrodes of polysomnography (PSG) and slept in the metabolic chamber for estimation of sleep structure, sleep metabolic rate (SMR), carbohydrate oxidation (CHOO), fat oxidation (FATO), and RQ. Fat-free mass (FFM) was measured by bioelectrical impedance analysis.ResultsThe sleep period time (p = 0.038) and total sleep time (p = 0.032) were significantly shorter in the obesity group than in the normal-weight group. The obesity group also had a longer sleep latency (p = 0.034) and more sleep-turning events (p = 0.018). CHOO/FFM and the RQ were higher in the obesity group while FATO/FFM was significantly higher in the normal-weight group. FATO/FFM was also higher in the normal-weight group in each sleep stage whereas the RQ was higher in the obesity group (p < 0.05).ConclusionsYoung males with obesity showed lower fat oxidation and more dominant carbohydrate-derived fuel oxidation than normal-weight during sleep and experienced shorter sleep periods and total sleep time.  相似文献   
78.
目的 比较改良的尖头梅花针与带锁髓内针治疗胫腓骨干骨折的临床综合疗效 ,正确选取内固定物。方法 分别用改良的尖头梅花针与带锁髓内钉内固定治疗胫腓骨干骨折 74例 ,比较两组的综合疗效。结果 改良梅花针组 48例 ,轻度外旋畸形 2例 ,无骨不愈合 ,平均骨折愈合时间 3.5个月 ,平均手术时间 40 mim ,住院费用 30 0 0元 (人民币 ) ,优良率93.75 % ;带锁髓内钉组 2 1例 ,发生骨延期愈合 2例 ,平均骨折愈合时间 5个月 ,平均手术时间 6 0 mim ,住院费用 5 5 0 0元(人民币 ) ,优良率 95 .2 4%。除胫骨远端下 1/ 3或严重的粉碎性骨折外 ,两组疗效无明显差异 (P >0 .0 5 )。结论 改良尖梅花针内固定操作简单、价格低廉、疗效确切 ,仍有较高的临床使用价值 ;带锁髓内钉能满足胫骨各种类型的骨折 ,扩大了髓内固定的适应症 ,随着成本的降低 ,已逐渐成为治疗胫腓骨骨折髓内固定的方向。  相似文献   
79.
全静脉营养液的合理应用   总被引:2,自引:1,他引:1  
目的:探讨全静脉营养液的合理应用,以避免或减少并发症的发生;方法:查文献,从适应证、营养状况评定、组方、配制、药物的加入、输入、监测及及时过渡到肠内营养几个方面综述全静脉营养液的合理应用;结果:营养状况的准确评定、科学组方、合理配制、规范输入、准确监测、以及及早过渡到肠内营养,是全静脉营养液合理应用的重要环节;结论:全静脉营养液的合理应用,对避免或减少并发症的发生,成功地进行完全胃肠外营养有重要意义。  相似文献   
80.
单纯性肥胖症瘦素水平的临床意义   总被引:2,自引:0,他引:2  
目的 :探讨单纯性肥胖症血清瘦素 (Leptin)及其临床意义。方法 :用ELISA法检测 48例单纯性肥胖症 (体重指数≥ 2 5 )和 40例健康对照者的血清Leptin水平。结果 :肥胖症组血清瘦素水平明显高于健康对照组 (P <0 .0 0 1) ,女性几乎较男性高 2倍以上。瘦素与BMI及脂肪含量呈正相关 (相关系数r分别为男性r =0 .36 ,0 .33 ,P <0 .0 5 ;女性r =0 .90 ,0 .87,P <0 .0 5 )。结论 :单纯性肥胖症血清瘦素水平升高 ,提示瘦素抵抗存在 ,可能在肥胖的发生发展中起重要作用  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