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   24383篇
  免费   1291篇
  国内免费   183篇
耳鼻咽喉   331篇
儿科学   455篇
妇产科学   556篇
基础医学   2920篇
口腔科学   767篇
临床医学   1982篇
内科学   6514篇
皮肤病学   410篇
神经病学   2430篇
特种医学   771篇
外科学   3631篇
综合类   98篇
一般理论   10篇
预防医学   1173篇
眼科学   321篇
药学   1615篇
  1篇
中国医学   45篇
肿瘤学   1827篇
  2023年   165篇
  2022年   365篇
  2021年   683篇
  2020年   398篇
  2019年   569篇
  2018年   659篇
  2017年   483篇
  2016年   581篇
  2015年   622篇
  2014年   941篇
  2013年   1212篇
  2012年   1879篇
  2011年   1869篇
  2010年   1086篇
  2009年   975篇
  2008年   1695篇
  2007年   1623篇
  2006年   1517篇
  2005年   1524篇
  2004年   1407篇
  2003年   1277篇
  2002年   1179篇
  2001年   185篇
  2000年   174篇
  1999年   188篇
  1998年   201篇
  1997年   189篇
  1996年   184篇
  1995年   172篇
  1994年   150篇
  1993年   123篇
  1992年   123篇
  1991年   69篇
  1990年   90篇
  1989年   83篇
  1988年   92篇
  1987年   96篇
  1986年   71篇
  1985年   85篇
  1984年   88篇
  1983年   85篇
  1982年   74篇
  1981年   69篇
  1980年   62篇
  1979年   41篇
  1978年   47篇
  1977年   32篇
  1976年   28篇
  1974年   29篇
  1971年   29篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
We prospectively evaluated the effectiveness of contrast-enhanced ultrasonography (CEUS) for differentiation of benign versus malignant portal vein thrombosis (PVT). We studied a total of 43 patients with chronic liver disease, hepatocellular carcinoma-suggestive nodules and confirmed PVT, in whom the nature of the PVT was confirmed by follow-up imaging (US, computed tomography and/or magnetic resonance imaging) performed up to 6 mo after CEUS. PVT was assessed by US, Doppler US and CEUS with respect to vessel wall disruption and/or invasion, color Doppler vascularization, pulsed Doppler vascularization pattern and CEUS enhancement and vascularization pattern, and thrombi were classified as benign or malignant based on these findings. Follow-up studies revealed malignant PVT in 22 of the 43 patients (51%) and benign PVT in 21 patients (49%). CEUS findings were consistent with follow-up studies in 41 of the 43 patients (95%), with κ?=?0.903 (p < 0.0001), sensitivity?=?91% and specificity?=?100%, indicating that CEUS can be confidently used to differentiate benign from malignant portal vein thrombosis in the setting of chronic liver disease.  相似文献   
5.
The effect of a newly developed patellar realignment brace was evaluated in 21 patellofemoral joints (19 patients) with patellar subluxation (13 joints with lateral subluxation and eight with medial subluxation) by using active-movement, loaded kinematic magnetic resonance (MR) imaging. Sixteen patellofemoral joints (76%) demonstrated a qualitative correction of or improvement in patellar subluxation (ie, centralization of the patella or a decrease in the displacement of the patella) after application of the brace. Four of the five “failures” occurred in patellofemoral joints that had patella alta and/or dysplastic bone anatomy. These results indicate that the patellar realignment brace was able to counteract patellar subluxation in the majority of patellofemoral joints studied, as shown by active-movement, loaded kinematic MR imaging. This brace appears to be useful for conservative treatment of patients with patellofemoral joint pain secondary to patellar malalignment and maltracking.  相似文献   
6.
7.
8.
Two linear vinyl polymers carrying amido and primary amino groups in the side chains were synthesized and characterized. Their behaviour in aqueous solution was investigated by potentiometric, viscometric and calorimetric techniques. In both cases, the basicity constants show a linear dependence on the degree of protonation α, while the enthalpy values of protonation do not. The thermodynamic results demonstrate the important role of hydrophobic interactions on the protonation process.  相似文献   
9.
10.
PURPOSE: Temporomandibular joint (TMJ) arthroscopy has been considered a safe surgical procedure in the treatment of TMJ derangement. However, it is not exempt from complications. This study evaluates the complications of arthroscopy in patients with internal derangement of TMJ. PATIENTS AND METHODS: Five hundred consecutive patients (670 joints) with TMJ derangement who underwent arthroscopy between 1995 and 2004 were retrospectively analyzed. All the patients were classified as II to V in the Wilkes classification. Lysis and lavage, electrocautery of the posterior ligament, injection of corticoids, injection of ethanolamine, myotomy of lateral pterygoid muscle attachments, myotomy and electrocautery, motor debridement, injection of sodium hyaluronate, and meniscal suture were performed in different patients. RESULTS: Complications were recognized during or immediately after the surgery. They were observed in 5 of 341 (1.26%) arthroscopies of the right TMJ and 4 of 329 (1.21%) arthroscopies of the left TMJ. A 1.34% complication rate was found in the whole series. No blood clots within the external auditory canal were observed. Bleeding within the superior TMJ space was observed in 57 cases (8.5%), 36 of them in the right TMJ and 21 in the left TMJ, but they were not considered as true complications. Lacerations of the external auditory canal were found in 2 cases (0.3%), with no cases of perforation of the tympanic membrane. Lesion of the auriculotemporal nerve was observed in a case. Paresia of the facial nerve was found in 4 cases (0.6%). Alteration of visual accuracy of the ipsilateral eye was also observed in a patient immediately after the surgery. CONCLUSION: Special care must be taken to reduce complications within the upper joint space by means of an adequate instrumentation and by paying attention to essential points of the arthroscopic technique.  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