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   24028篇
  免费   1656篇
  国内免费   1006篇
耳鼻咽喉   56篇
儿科学   149篇
妇产科学   209篇
基础医学   2259篇
口腔科学   423篇
临床医学   1223篇
内科学   2235篇
皮肤病学   329篇
神经病学   1849篇
特种医学   346篇
外国民族医学   2篇
外科学   1214篇
综合类   2698篇
现状与发展   2篇
预防医学   631篇
眼科学   147篇
药学   10532篇
  12篇
中国医学   2074篇
肿瘤学   300篇
  2024年   56篇
  2023年   232篇
  2022年   515篇
  2021年   782篇
  2020年   638篇
  2019年   550篇
  2018年   565篇
  2017年   619篇
  2016年   750篇
  2015年   719篇
  2014年   1489篇
  2013年   2037篇
  2012年   1500篇
  2011年   1510篇
  2010年   1159篇
  2009年   1103篇
  2008年   1143篇
  2007年   1245篇
  2006年   980篇
  2005年   885篇
  2004年   713篇
  2003年   643篇
  2002年   536篇
  2001年   452篇
  2000年   434篇
  1999年   401篇
  1998年   362篇
  1997年   344篇
  1996年   331篇
  1995年   313篇
  1994年   286篇
  1993年   266篇
  1992年   249篇
  1991年   210篇
  1990年   228篇
  1989年   212篇
  1988年   193篇
  1987年   164篇
  1986年   192篇
  1985年   248篇
  1984年   235篇
  1983年   190篇
  1982年   224篇
  1981年   196篇
  1980年   146篇
  1979年   106篇
  1978年   92篇
  1977年   58篇
  1976年   58篇
  1975年   34篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
微囊化吲哚美辛片剂的研讨   总被引:2,自引:0,他引:2  
以明胶-CAP 为囊材,经复凝聚法制备吲哚美辛微囊,再按所筛选的最佳处方制备微囊化片剂。该片与市售片相比,体外 T_(50)延长约5.6倍,家兔体内达峰时间滞后,能明显减轻对大鼠胃的刺激性。  相似文献   
52.
Frozen shoulder is said to be a self-limiting entity but full recovery often takes more than 2 years. For that, most patients are unwilling to tolerate painful restriction while awaiting resolution. We prospectively investigated 30 patients (16 women, 14 men) for the outcome of arthroscopic capsular release in idiopathic frozen shoulder. Results were determined by the assessment of subjective and objective parameters to estimate both shoulder function and general health status. Symptoms persisted without improvement for a minimum of 6 months of conservative treatment. Preoperative average American shoulder and elbow surgeons score (ASES) was 35, visual analog scale (VAS) to measure pain was 7, and simple shoulder test (SST) was 4. Mean scores of the physical component of SF-36 were considerably reduced. Mean forward elevation was 85°, average abduction was 70°, mean internal rotation was 15°, and mean external rotation was 10°. Patients were followed-up at 6 weeks, 3, 6, 12 months and by a mean of 36 months. Range of motion for all planes improved (P < 0.05). Median VAS reduced to 2, average ASES increased to 91, and SST enhanced to a mean of 10 (P < 0.05). We stated improvement of the physical components in the SF-36 questionnaire in particular bodily pain and the role-physical score. There were no significant differences between the measurements in the early postoperative phase compared to the mid-term follow-up (P > 0.05). Our results demonstrate that arthroscopic release of refractory idiopathic frozen shoulder combined with a gentle manipulation provides reliable expectations for improvement in both clinical and general health status for most patients. We recommend the use of a limb-specific and a general-health-status questionnaire to conclude the benefit of the surgical intervention and contribute the optimization of a therapy concept more effectively.  相似文献   
53.
目的 探讨膝关节纤维性僵直手术及围手术期、术后综合康复治疗的方法和意义.方法 26例膝关节纤维性僵直患者,采用髌骨外上方小切口,辅助关节镜下行关节内粘连松解,并结合徒手推拿松解.术前进行心理宣教,术后第2天开始经止痛泵维持在CPM机上行慢速全范围关节活动度功能锻炼,并行主被动伸屈膝功能锻炼、髌骨内推训练.结果 术后平均随访19个月(8~32个月),膝关节活动度从术前平均32°增至113°,平均提高81°.无皮肤坏死、创口裂开、肌腱断裂、骨折等并发症发生.结论 关节镜辅助下小切口松解治疗膝关节纤维性僵直的手术操作简单,创伤小,康复快.膝关节僵直围手术期及术后综合康复治疗,对膝关节功能恢复有重要意义.  相似文献   
54.
55.
The expression of somatostatin receptors 1 and 2 in benign, pre‐malignant and malignant laryngeal lesions The role of chemotherapy in squamous cell carcinoma of the larynx has not been clearly defined. Whilst toxic chemotherapy regimes may confer a marginal improvement in survival, surgery and radiotherapy remain the mainstay of treatment. Somatostatin is a naturally occurring peptide, which exerts antiproliferative and antiangiogenic effects via five membrane‐bound receptor subtypes. The expression of somatostatin receptor subtypes (SSTRs) 1 and 2 was studied in benign, pre‐malignant and malignant laryngeal specimens. Epithelial expression of SSTR1 was detected in 4/6 (67%) Reinke's oedema, 5/6 (83%) pre‐malignant and 8/12 (67%) malignant specimens, with virtually no stromal or vascular expression. High levels of epithelial SSTR2 expression were noted in all Reinke's oedema specimens, compared with low‐to‐moderate levels in only 2/6 (33%) pre‐malignant and 3/12 (25%) malignant specimens (P < 0.01). This ‘loss’ of epithelial SSTR2 expression may provide a growth advantage in pre‐malignant and malignant laryngeal lesions. Vascular expression of SSTR2 was ubiquitous in all groups, with scant stromal expression. Overall, most (>80%) pre‐malignant and malignant laryngeal specimens expressed at least one of the two SSTR subtypes studied. Somatostatin analogues may have a therapeutic role in squamous cell carcinoma of the larynx.  相似文献   
56.
目的:研究原料药粒径等对盐酸普萘洛尔渗透泵片释药行为的影响。方法:取不同批号盐酸普萘洛尔及同批号重结晶前、后的原料药均按相同处方制备成渗透泵片,考察药物体外释放情况及释药24h后衣膜形态;并对上述不同原料药的粒径分别以光学显微镜和激光粒度分析仪进行证实。结果:以原料药粒径较小的渗透泵片释放完毕后衣膜变形,且不能维持零级释放,原料药粒径较大的渗透泵片结果与之相反。不同原料药经仪器证实粒径确有差异。结论:原料药的粒径可影响制备的渗透泵片的释放行为,提示性状稳定的原料药的合理选择在制剂过程中不可忽视。  相似文献   
57.
58.
Repeated isolation of neonatal rats produces persistent changes in physiology and behavior. In Experiment 1, we examined changes in plasma corticosterone (CORT) levels as a possible mechanism for the effects of isolation. Pups that were isolated from their mother and the nest for 1 h per day on postnatal days (PND) 2–9 were compared to control litters of pups that were either nonhandled or handled but not isolated. On PND 2, compared to nonhandled pups, handled pups had elevated CORT levels that returned to baseline levels within 30 to 60 min of return to the home cage. No significant elevation of CORT levels were found in handled pups on PND 9. The CORT levels of isolated pups were over twice those of nonhandled pups on PND 2 and four times those of nonhandled pups on PND 9. In Experiment 2, we investigated whether the increased CORT release in response to isolation on PND 9 was the result of the pups treatment on the previous six days as against an effect of maturation. Plasma CORT levels were measured in rat pups that were either isolated, handled or nonhandled on PNDs 2–8 during the conditions of isolation, handling and nonhandling on PND 9. There were no differences among the groups in basal plasma levels of CORT. Handling on PND 9 did not result in elevated CORT levels in any of the groups. All three groups showed a significant increase in plasma CORT levels after isolation on PND 9. However, the CORT response to isolation of pups previously isolated on PND 2–8 were significantly higher than pups that were either handled or nonhandled on PNDs 2–8. Thus, daily episodes of isolation potentiate the hypothalamic-pituitary-adrenal response to stress.  相似文献   
59.
C.A. Ayala  E.H. Jaffe   《Neuropharmacology》1993,32(12):1401-1409
The release of endogenous DA and DOPAC from nucleus accumbens slices were studied measuring net outflow of DA and DOPAC in the superfusate of static chambers, to analyze the correlation between DA and DOPAC outflows and identify which DA stores may serve as possible sources for DOPAC formation. Under resting conditions, or following stimulation with low (< 15 mM) KCl concentration, DOPAC outflow was greater than DA. When DA release was stimulated by higher (> 25 mM) KCl concentrations, DA outflow increased, proportionally more than DOPAC. In the virtual absence of Ca2+ in the Krebs solution DA outflow, induced by 25 mM KCl, was reduced to about 10%, while DOPAC outflow was only reduced to 45%. When the synthesis of DA was inhibited with -MPT, DA and DOPAC outflow were unchanged during the first stimulation period. During a second stimulation period, however, their outflow were significantly reduced. Nomifensine, a DA uptake inhibitor, increased the basal DA outflow by about 100%, but only blocked DOPAC basal outflow by about 25%. The 25 mM KCl stimulated DA outflow was not affected by Nomifensine, while the stimulated DOPAC outflow was reduced by about 50%. These results demonstrate that there is a weak correlation between the outflows of DA and DOPAC, suggesting a complex relationship between the mobilization of the different DA pools and DOPAC outflow. The formation of DOPAC from some of these pools, appear to be dependent on the stimulation levels and on the pharmacological manipulation of the tissue.  相似文献   
60.
用线性变温法对硫酸链霉素粉针的稳定性进行了测定,得出25℃时的降解反应速度常数 k_(25)为1.744×10~(-6)h~(-1)、化学反应的表观活化能为107.9kJ/mol,25℃时贮存的 t_(0.9)为6.9年。  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