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   48831篇
  免费   2919篇
  国内免费   463篇
耳鼻咽喉   754篇
儿科学   1793篇
妇产科学   791篇
基础医学   6189篇
口腔科学   1150篇
临床医学   3555篇
内科学   11589篇
皮肤病学   1438篇
神经病学   4006篇
特种医学   1331篇
外国民族医学   2篇
外科学   6378篇
综合类   1301篇
一般理论   16篇
预防医学   4031篇
眼科学   1441篇
药学   3212篇
  6篇
中国医学   495篇
肿瘤学   2735篇
  2024年   42篇
  2023年   380篇
  2022年   432篇
  2021年   1384篇
  2020年   760篇
  2019年   1387篇
  2018年   2140篇
  2017年   1308篇
  2016年   1149篇
  2015年   1159篇
  2014年   1385篇
  2013年   2128篇
  2012年   3597篇
  2011年   4049篇
  2010年   1988篇
  2009年   1273篇
  2008年   3097篇
  2007年   3140篇
  2006年   2858篇
  2005年   2923篇
  2004年   2670篇
  2003年   2569篇
  2002年   2325篇
  2001年   1624篇
  2000年   2002篇
  1999年   1179篇
  1998年   331篇
  1997年   220篇
  1996年   218篇
  1995年   199篇
  1994年   133篇
  1993年   123篇
  1992年   226篇
  1991年   173篇
  1990年   157篇
  1989年   154篇
  1988年   156篇
  1987年   125篇
  1986年   110篇
  1985年   109篇
  1984年   99篇
  1983年   69篇
  1982年   56篇
  1981年   45篇
  1980年   46篇
  1979年   48篇
  1978年   51篇
  1977年   39篇
  1975年   44篇
  1973年   38篇
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
91.
92.
93.
A method of electrostimulation aimed at activation of bone adhesion processes was developed and introduced into practice at the Latvian Research Institute of Traumatology and Orthopedics on the basis of data on bone bioelectric activity. The method was used in complex with external fixation of the fracture by Kalnbers' apparatus. The phase pattern of callus formation necessitated the employment of the appropriate potential of direct current. Cyclic potentials similar to piezopotentials of a normal bone in cyclic physiological load were used in the phase of functional reorganization. Positive results were achieved in 88.4% of 79 patients.  相似文献   
94.
Endometriosis in episiotomy scar with anal sphincter involvement   总被引:2,自引:1,他引:1  
A case of endometriosis in an episiotomy scar with involvement of the external anal sphincter is presented. The clinical, operative, and pathologic findings are reported. The question of etiology and treatment is discussed, and the literature is reviewed. Wide excision of the ectopic endometrial tissue with primary reconstruction of the external sphincter was curative, and the functional result was excellent. It is suggested that this treatment policy should be recommended for these cases.  相似文献   
95.
The purpose of this study was to evaluate the ability of helical computed tomography (CT) to detect arterial injuries in gunshot wounds to the neck. In a blinded retrospective review, 54 helical CT scans of the cervical spine were evaluated for bullet/bone fragments, subcutaneous air, bullet path, hematoma, spine fractures, and pharyngoesophageal compromise. The distance of fragments to a major vessel was calculated. CT findings that correlated significantly with major arterial injury included the presence of fragments (bullet/bone) close to a major vessel (2.5 mm) and spine fractures. Visualizing fragments <5 mm from a vessel or a transcervical bullet trajectory predicted 12 of 13 major arterial injuries. We conclude that CT clearly depicts anatomic damage. Specific findings, such as the location of fragments and bullet trajectory adjacent to a vessel and spine fractures, indicate a higher probability of vascular damage, thus directing more definitive evaluation.  相似文献   
96.
Moderate increases in ``classical' biochemical markers of bone turnover have been described only in some patients with Camurati–Engelmann disease. However, the determination of the following ``new' markers has not been previously performed: serum osteocalcin (BGP), bone alkaline phosphatase (BAP), carboxyterminal propeptide of type I procollagen (PICP), aminoterminal propeptide of type I procollagen (PINP), tartrate-resistant acid phosphatase (TRAP), telopeptide carboxyterminal of type I collagen (ICTP), urinary pyridinoline (PYR), crosslinked N-telopeptides of type I collagen (NTX), and Crosslaps (CL). Such a determination may improve the evaluation of the disease activity. To evaluate the usefulness of biochemical markers of bone turnover reflecting Camurati–Engelmann disease activity we measured the levels of all these markers in four affected patients. The results were compared with bone scintigraphic indices of disease activity. Except for PICP and TRAP, bone formation and resorption markers were abnormal in all patients and were related to bone scan indices of disease activity. Among the markers of bone formation PINP, BAP, and BGP showed the highest values, whereas NTX and CL were the most sensitive markers of bone resorption. These results suggest that the determination of NTX or CL, and PINP or either BAP and BGP, associated with bone scan evaluation, provides the best assessment of Camurati–Engelmann disease activity. Received: 14 June 1996 / Accepted: 31 December 1996  相似文献   
97.
Summary A rapid and quantitative method for the determination of benzodiazepines using high-performance liquid chromatography (HPLC) with diode-array detection (DAD) is reported. The drugs were extracted from serum, blood or post-mortem blood using C18 extraction columns. Brotizolam was used as internal standard. Experiments with spiked serum/blood samples resulted in recoveries between 75% and 94% for all investigated benzodiazepines. Excellent linearity was obtained over the concentration range 5–1500 ng benzodiazepine/ml. The limit of detection was approximately 2 ng/ml. The detection of low therapeutic serum levels of highly potent benzodiazepines is also possible.   相似文献   
98.
The possible immunoregulatory role of the tonsils was studied by determining immunoglobulins IgG, A, M, E and factors C'3, C'4 and PFB of the complement system before and after tonsillectomy. The synthesis in vitro of IgG and IgM by lymphocytes stimulated with pokeweed mitogen was also measured. There were statistically significant differences between pre and post-operative levels of serum IgG, IgA and IgM, which decreased after surgery. Practically no change in the mean values of IgE and no significant differences in the levels of serum C'3, C'4, and PFB, were found. The in-vitro synthesis of both immunoglobulins (IgG, IgM) by lymphocytes increased significantly after tonsillectomy. Our results suggest that not only does tonsillectomy have no counterproductive effect on the immune system, but that, on the contrary, it seems to improve the immune response, since it appears to unblock the suppression to which the immune system was subject.  相似文献   
99.
79只眼底病患眼的光照黄斑部试验(MPT)结果显示:中心性浆液性脉络膜视网膜病变、老年性黄斑变性渗出型和Rieger型中心性渗出性脉络膜视网膜病变患眼的光照黄斑恢复时间显著延长,其它黄斑部病变患眼也有不同程度的延长。本文结合眼底荧光血管造影和黄斑视野域值试验对光照黄斑部试验的机理进行了探讨。  相似文献   
100.
Pleural effusion in patients infected with the human immunodeficiency virus   总被引:1,自引:0,他引:1  
In order to analyze the etiology, cytological and biochemical characteristics, and outcome of pleural disease in patients infected with HIV, the medical records of 86 HIV-positive patients with pleural effusion were reviewed. Controls were 106 HIV-negative patients with parapneumonic or tuberculous effusion. Most HIV-positive patients were intravenous drug abusers (95.3%). Pleural effusions in HIV-positive patients were caused by infections in 76 (89.4%) cases. Parapneumonic effusion was diagnosed in 59 patients and tuberculous pleuritis in 15 patients.Staphylococcus aureus was the most frequently isolated bacteria. Parameters for differentiating complicated cases of parapneumonic exudate from uncomplicated cases, such as pleural fluid pH<7.20 (sensitivity 80% vs. 84.3%), pleural fluid glucose<35 mg/dl (sensitivity 45% vs. 56.25%) pleural fluid LDH > 1600 Ul/l (sensitivity 85% vs. 62.50%), showed similar sensitivity in HIV-positive and HIV-negative patients. Monocytes in pleural fluid were significantly decreased in tuberculous pleuritis in HIV-positive patients (506±425 vs. 1014±1196 monocytes/ml, p<0.05). No significant differences were detected in the outcome of HIV-positive and HIV-negative patients with pleural disease. It can be concluded that the pleural effusion was of predominantly infectious etiology in HIV-positive patients from populations with a high prevalence of intravenous drug abuse. Neither the biochemical parameters in pleural fluid nor the outcome differed significantly between HIV-positive and HIV-negative patients.  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