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   94584篇
  免费   6587篇
  国内免费   3385篇
耳鼻咽喉   588篇
儿科学   2149篇
妇产科学   1276篇
基础医学   9626篇
口腔科学   538篇
临床医学   14358篇
内科学   12290篇
皮肤病学   428篇
神经病学   8935篇
特种医学   3910篇
外国民族医学   6篇
外科学   10353篇
综合类   16255篇
现状与发展   9篇
预防医学   5089篇
眼科学   770篇
药学   8223篇
  81篇
中国医学   7676篇
肿瘤学   1996篇
  2024年   197篇
  2023年   1234篇
  2022年   1929篇
  2021年   3401篇
  2020年   3222篇
  2019年   2610篇
  2018年   2588篇
  2017年   2897篇
  2016年   2936篇
  2015年   3003篇
  2014年   5611篇
  2013年   6521篇
  2012年   5070篇
  2011年   5570篇
  2010年   4530篇
  2009年   4133篇
  2008年   4276篇
  2007年   4433篇
  2006年   4015篇
  2005年   3628篇
  2004年   3271篇
  2003年   3030篇
  2002年   2639篇
  2001年   2473篇
  2000年   2068篇
  1999年   1789篇
  1998年   1633篇
  1997年   1703篇
  1996年   1355篇
  1995年   1287篇
  1994年   1233篇
  1993年   957篇
  1992年   975篇
  1991年   857篇
  1990年   711篇
  1989年   672篇
  1988年   636篇
  1987年   543篇
  1986年   543篇
  1985年   774篇
  1984年   657篇
  1983年   455篇
  1982年   543篇
  1981年   421篇
  1980年   385篇
  1979年   246篇
  1978年   202篇
  1977年   193篇
  1976年   156篇
  1975年   83篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
目的探讨剖宫产术后深静脉血栓的护理经验。方法将2003年1月~2005年12月行剖宫产术的产妇76例,采取护理干预,加强饮食指导、抗凝血及溶栓护理。结果70例患者治愈,4例留有后遗症,2例转院,未跟踪报告。结论剖宫产术后易发生深静脉血栓;而高龄、经产、多胎、有产科并发症是其高危因素;应用护理措施进行积极干预,起到较好的预防作用,能保证产妇生命安全,提高产科护理质量。  相似文献   
82.
血栓的形成及中药抗栓溶栓概况   总被引:11,自引:0,他引:11  
血栓形成是由于正常的凝血机制的扰乱而促使某些血细胞和蛋白质被激活相互作用而最终导致血小板-纤维蛋白血栓的形成.AT-Ⅲ、PC、TM是体内重要的抗凝物质.白细胞与血小板的相互作用、PGI2/TXA2值以及许多疾病状态是影响血栓形成的诸因素.许多中药具有抗血小板聚集、抗血栓形成的作用,包括生物碱类,如小檗碱、北豆根碱和钩藤碱;中药蒲黄、花椒、沙棘、大蒜的提取物;一些中药复方等.  相似文献   
83.
Thirty-four patients with bilateral vocal cord abductor paralysis were treated surgically during the period from 1960 to 1979. The main cause of paralysis was thyroid surgery (85%). Woodman's external laterofixation was performed in 31 patients, 1 had laterofixation by laryngofissure and 2 had endoscopic arytenoidectomy. In Woodman's procedure the body of the arytenoid cartilage was removed in 10 cases and mobilized from the cricoarytenoid joint in 21 cases. Thirteen of the 34 patients needed further surgery. Including previously performed procedures in 6 patients, altogether 68 operations were performed and 17 patients (50%) were operated on more than once. The immediate failure rate of laterofixation was 22% but the need for reoperation increased with time and the total failure rate of the method was 44%. Endoscopic arytenoidectomy was successful in 1 of 2 cases as a primary operation and in 3 of 3 cases as secondary operation. Follow-up time ranged from 2 months to 29 years 8 months (mean 15 years 10 months).  相似文献   
84.
1. The relationship between work-rate and the antihypertensive effect of exercise in hypertensives, and the mechanism of that effect, were investigated by a crossover clinical trial. 2. Ten mild hypertensives were randomly divided into two groups. One group performed low work-rate exercise (LWE) on a cycle ergometer for 10 weeks (blood lactate threshold; ~50% of maximum oxygen consumption [V?O2max]). After a 10 week interval without exercise training, these subjects were then switched to a high work-rate exercise (HWE) regimen (4 mmol/ L of blood lactate; ~75% of V?O2max) for another 10 weeks. In the other group, the order of exercise training was reversed. Since two patients withdrew from the protocol during HWE periods, statistical analysis was performed on the data from the remaining eight patients. There were no order effects observed in any of the data from the two groups. 3. During both LWE and HWE, resting blood pressure (BP) fell significantly after the initiation of exercise therapy (P<0.05). Furthermore, the overall effects of 10 weeks of LWE and HWE on BP were not significantly different. 4. The work-rate at the lactate threshold, which reflects physical fitness, had increased significantly by 16 W (P<0.01) after the LWE period and by 11 W (P<0.01) after the HWE. 5. During the LWE period, changes in haemodynamic and humoral variables were not significant, except for a reduction in plasma norepinephrine at week 10 (P<0.05). In the HWE period, changes in haemodynamic and humoral variables were not significant. 6. Based on these findings, LWE is recommended for mild hypertensives because of its safety.  相似文献   
85.
The effects of daily oral administration of a high dose of 10 mg norethisterone acetate (NET-Ac.)/kg/day over 14 weeks on serum lipid and lipoprotein parameters as well as on blood coagulation were investigated in female monkeys (M. fascicularis). Measurements of lipids and lipoprotein cholesterol were performed in weeks —5 and — 1 before treatment and in weeks 4, 8 and 12 after treatment. In addition, various blood coagulation and fibrinolytic parameters were determined in weeks 11–14 after treatment with NET-Ac. Furthermore, the serum levels of norethisterone (NET) were determined in order to monitor the real systemic compound exposure and revealed that Cmax and AUC (0–3 h) values reached for norethisterone in this experiment in monkeys were about 25 times higher than those obtained after an oral contraceptive dose of NET-Ac. in women.

The results of lipid and lipoprotein cholesterol determinations showed decreases in serum total lipids, phospholipids, triglycerides and total cholesterol associated with similar decreases in HDL-, LDL- and VLDL-cholesterol fractions after NET-Ac.-treatment in monkeys. These effects were observed from week 4 onwards and maintained their magnitude up to week 12 after treatment. Since both HDL- and LDL-cholesterol fractions decreased, the HDL/LDL-ratio remained almost unchanged. Thus, the results obtained in this study after high-dose treatment with NET-Ac. in monkeys did not indicate any changes of lipid and lipoprotein parameters which in humans are supposed to be associated with an increased risk of cardiovascular lesions, namely a decrease in HDL- and increase in LDL-cholesterol fractions.

The results of blood coagulation and fibrinolytic parameters showed increased antithrombin-III and plasminogen levels besides minor changes in other parameters, thus indicating that NET-Ac. -treatment does not contribute to an increased risk of cardiovascular thrombotic events in the cynomolgus monkey.  相似文献   

86.
Spinal epidural hematoma. Report of a case and review of the literature   总被引:3,自引:0,他引:3  
We report the case of a thoracic epidural hematoma at the T7-T9 level which occurred after placement of spinal epidural catheter for continuous anaesthesia in acute pancreatitis. The male patient felt a sudden back pain after six days of successful analgesia and became paraplegic 24 hours afterwards. An emergency laminectomy and removal of the hematoma were performed; however, the patient recovered only incompletely.We discuss the clinical signs and symptoms of spinal epidural hematoma as well as its diagnostics and therapy. The controversial views from the literature concernings its etiology are critically reviewed.  相似文献   
87.
目的:观察双侧颈总动脉阻断后脑血流的变化。方法:结扎双侧颈总动脉观察小鼠不完全性脑缺血及其再灌注时脑膜血流量的变化。结果:结扎颈总动脉后小鼠脑膜血流量在几秒钟内骤然下降,血流量较结扎前降低约85.9%±6.45%。同时血管中红细胞运动近停滞状态,血管再通时脑血流处于低灌注状态,血流量下降34.47%±11.69%,此时脑缺血再灌后脑组织实际上处于一种慢性缺血状态。再灌注10d后,小鼠脑海马CA1区神经细胞数明显减少。尼莫地平可以解除再灌注时的脑血流低灌状态。并防止由此所引起的脑海马CA1区神经细胞的缺失。结论:缺血后及时给予尼莫地平具有积极的治疗意义。  相似文献   
88.
对13例体外循环病人进行了观察,发现体外循环后TXB2/6-keto-PGF1α显著增高,表明体外循环使血小板受损,而血小板受损是体外循环后失血的主要原因之一。  相似文献   
89.
90.
Image-directed color Doppler ultrasonography (ICDUS) studies of 86 patients with superficial solid masses yielded significantly lower resistive index (RI) values in acute inflammatory lesions, but no significant difference between the maximum systolic flow velocities (S) of the patient groups with malignant, benign, and acute inflammatory lesions. When analyzed separately, the malignant soft-tissue tumor subgroup was shown to have significantly higher mean RI compared to that of the malignant node subgroup. We conclude that RI may be useful in the differentiation of acute inflammatory masses from other pathological entities. Malignant soft-tissue tumors, especially sarcomas, may have different Doppler features from those of carcinomatous tumors. © 1995 John Wiley & Sons, Inc.  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