全文获取类型
收费全文 | 332789篇 |
免费 | 15092篇 |
国内免费 | 8317篇 |
专业分类
耳鼻咽喉 | 2849篇 |
儿科学 | 8933篇 |
妇产科学 | 6562篇 |
基础医学 | 33259篇 |
口腔科学 | 4729篇 |
临床医学 | 31912篇 |
内科学 | 55720篇 |
皮肤病学 | 3018篇 |
神经病学 | 24288篇 |
特种医学 | 14102篇 |
外国民族医学 | 55篇 |
外科学 | 44975篇 |
综合类 | 25535篇 |
现状与发展 | 24篇 |
一般理论 | 25篇 |
预防医学 | 29410篇 |
眼科学 | 6864篇 |
药学 | 26024篇 |
135篇 | |
中国医学 | 8691篇 |
肿瘤学 | 29088篇 |
出版年
2024年 | 423篇 |
2023年 | 2141篇 |
2022年 | 5052篇 |
2021年 | 6814篇 |
2020年 | 5061篇 |
2019年 | 4727篇 |
2018年 | 26588篇 |
2017年 | 21713篇 |
2016年 | 23437篇 |
2015年 | 7475篇 |
2014年 | 9213篇 |
2013年 | 9345篇 |
2012年 | 19267篇 |
2011年 | 33990篇 |
2010年 | 27524篇 |
2009年 | 18676篇 |
2008年 | 28691篇 |
2007年 | 30718篇 |
2006年 | 9460篇 |
2005年 | 10435篇 |
2004年 | 9333篇 |
2003年 | 9811篇 |
2002年 | 7081篇 |
2001年 | 4186篇 |
2000年 | 4020篇 |
1999年 | 3498篇 |
1998年 | 1939篇 |
1997年 | 1814篇 |
1996年 | 1387篇 |
1995年 | 1338篇 |
1994年 | 1238篇 |
1993年 | 749篇 |
1992年 | 1230篇 |
1991年 | 1155篇 |
1990年 | 1000篇 |
1989年 | 804篇 |
1988年 | 759篇 |
1987年 | 637篇 |
1986年 | 499篇 |
1985年 | 426篇 |
1984年 | 285篇 |
1983年 | 231篇 |
1982年 | 143篇 |
1981年 | 127篇 |
1980年 | 126篇 |
1979年 | 173篇 |
1978年 | 143篇 |
1977年 | 105篇 |
1974年 | 127篇 |
1972年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Depeng Meng Yichen Meng Bingyang Li Guigang Zeng Bin Zhang Chunlin Hou Haodong Lin Yueping Ouyang 《Journal of orthopaedic science》2021,26(3):409-414
BackgroundComminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures.MethodsFrom March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed.ResultsIn total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05).ConclusionsTreatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments. 相似文献
3.
4.
Hyun Jong Choi Jong Ho Moon Yun Nah Lee Hyun Su Kim Ji Su Ha Tae Hoon Lee Sang‐Woo Cha Young Deok Cho Sang‐Heum Park 《Digestive endoscopy》2015,27(7):772-775
Direct peroral cholangioscopy (POC) using an ultra‐slim upper endoscope is one modality of POC for intraductal endoscopic evaluation and treatment of the bile duct. Choledochoduodenostomy (CDS) is one modality of biliary bypass surgery that provides a new route to the bile duct. We carried out direct POC using an ultra‐slim upper endoscope without the use of accessories in 10 patients (four sump syndromes, three bile duct strictures and three intrahepatic duct stones) previously undergoing surgical CDS. Direct POC was successful in all patients. The use of an intraductal balloon catheter was required in one patient for advancement of the endoscope into the bile duct. Distal bile ducts with sump syndromes were cleared using baskets and water irrigation under direct POC. Cholangiocarcinoma was diagnosed in one patient with hilar bile duct stricture after cholangioscopic evaluation and a targeting forceps biopsy under direct POC. Intrahepatic duct stones were successfully extracted after intraductal fragmentation under direct POC. Oozing bleeding occurred during intraductal lithotripsy but stopped spontaneously. Direct POC using an ultra‐slim upper endoscope without the assistance of accessories can easily be carried out in patients undergoing CDS. 相似文献
5.
Seyed Mehdi BagheriMofidi Majid Pouladian Seyed Behnamedin Jameie Ali Abbaspour Tehrani-Fard 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2016,39(3):717-726
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. 相似文献
6.
7.
8.
9.
10.
Yinlei
Wen Huaguang Zhang Hanguang Su He Ren 《Optimal control applications & methods.》2020,41(4):1233-1250
In this article, a model-free off-policy reinforcement learning algorithm is applied to address the optimal tracking problem based on multiplayer non-zero-sum games for discrete-time linear systems. In contrast to the traditional method and the policy iteration method for solving the optimal tracking problems, the proposed algorithm operates with the system data rather than the knowledge of the system dynamics. For performing the proposed algorithm, an auxiliary augmented system is constructed via assembling the original system and the reference trajectory while a discount factor is introduced into the performance indexes. It is analyzed that the solutions of the proposed algorithm converge to the Nash equilibrium and the result is not influenced by the probing noise. Two simulations are presented to verify the feasibility and effectiveness of the proposed algorithm. 相似文献