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   24013篇
  免费   1594篇
  国内免费   238篇
耳鼻咽喉   380篇
儿科学   463篇
妇产科学   311篇
基础医学   4000篇
口腔科学   458篇
临床医学   2004篇
内科学   4788篇
皮肤病学   778篇
神经病学   1971篇
特种医学   1516篇
外科学   3139篇
综合类   105篇
一般理论   4篇
预防医学   907篇
眼科学   505篇
药学   2196篇
  1篇
中国医学   297篇
肿瘤学   2022篇
  2023年   144篇
  2022年   490篇
  2021年   839篇
  2020年   431篇
  2019年   605篇
  2018年   711篇
  2017年   540篇
  2016年   812篇
  2015年   1039篇
  2014年   1178篇
  2013年   1416篇
  2012年   2036篇
  2011年   1954篇
  2010年   1157篇
  2009年   988篇
  2008年   1426篇
  2007年   1338篇
  2006年   1249篇
  2005年   1125篇
  2004年   972篇
  2003年   850篇
  2002年   743篇
  2001年   446篇
  2000年   422篇
  1999年   367篇
  1998年   257篇
  1997年   237篇
  1996年   222篇
  1995年   174篇
  1994年   159篇
  1993年   163篇
  1992年   117篇
  1991年   116篇
  1990年   96篇
  1989年   117篇
  1988年   113篇
  1987年   92篇
  1986年   83篇
  1985年   83篇
  1984年   53篇
  1983年   56篇
  1982年   45篇
  1981年   53篇
  1980年   44篇
  1979年   46篇
  1978年   27篇
  1977年   36篇
  1976年   35篇
  1975年   20篇
  1969年   15篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
61.
We present a case of benign osteoblastoma of the occipital bone. Benign osteoblastoma is an uncommon primary bone tumor, which usually involves the vertebrae and the long bones. This tumor rarely develops in the calvaria, showing a preference for the temporal and frontal bones when it does. To the best of our knowledge, this case is only the eighth reported case of benign osteoblastoma confined to the occipital bone. A 20‐year‐old male presented with a mild tender mass lesion of the occipital area, just below the lambda. Plain X‐ray films and CT scans demonstrated an osteolytic mass surrounded by the sclerotic rim within the diploic space. MRI proved to be effective for the evaluation of the intracranial and intraosseous extensions of the tumor. However, it was very difficult to formulate a differential diagnosis against other osteoblastic tumors, or osteoid osteoma, in view of its radiological appearance. The final diagnosis was obtained by careful consideration of the histopathological characteristics of the tumor combined with its clinical and radiological features. Although generally regarded as benign, a complete resection is preferred over conventional curettage as this can guard against possible recurrence and malignant transformation.  相似文献   
62.
The pharmacokinetics of oral Alminoprofen, a nonsteroidal anti-inflammatory drug, were studied in five elderly patients with rheumatoid arthritis and spondylosis deformans after 200 mg (three times a day) repeated dose for 5 days. The pharmacokinetic parameters after oral administration of Alminoprofen were analyzed by the one-compartment open model method. The maximum plasma concentrations (Cmax) were 16.1 +/- 2.5 micrograms/ml, after dosing on day 1, 25.2 +/- 1.6 micrograms/ml on day 3 and 21.6 +/- 2.7 micrograms/ml on day 5. The maximum time (Tmax) were about 2 hours after the medication in al cases. The area under the curve in drug concentration in plasma versus time (AUC) were 58.5 +/- 6.3 micrograms hr/ml on day 1, 58.5 +/- 3.1 micrograms hr/ml on day 3 and 58.1 +/- 8.5 micrograms hr/ml on day 5. The biological half-lives (t1/2) were 2.45 +/- 0.35, 2.09 +/- 0.82 and 2.49 +/- 0.63 hours, after dosing on day 1, day 3 and day 5, respectively. The analysis of moment in pharmacokinetics revealed that the mean residence time (MRT) on day 1, day 3 and day 5 observed were 2.31 +/- 0.03, 2.15 +/- 0.09 and 2.15 +/- 0.07 hours, respectively. The variance residence times (VRT) observed were 0.95 +/- 0.05 hour2 on day 1, 0.88 +/- 0.09 hour2 on day 3 and 1.06 +/- 0.07 hour2 on day 5. The ratios of accumulation calculated were 1.16 +/- 0.05 in both the morning medication on day 3 day 5, and it therefore appears that the steady-state equilibrium is established within 3 days after commencement of dosage.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
63.
64.
From October, 1980, to June, 1987, thirty-eight infants less than one year old underwent correction for total anomalous pulmonary venous connection (TAPVC). Overall operative mortality and late mortality were 13% and 6%, respectively. Residual pulmonary hypertension was noted in 4 patients: three had pulmonary venous obstruction at the site of atrial anastomosis (PVOA) and one had supracardiac (Ia) lesion left after repair of mixed type (IV: Ia + III) of TAPVC. Two late deaths occurred in these with PVOA. Twenty-two patients with supracardiac (I) or infracardiac (III) TAPVC were divided into three groups according to the technical development in atrial anastomosis: the large anastomosis in which venous incision reached into at least one pulmonary vein beyond common pulmonary vein and the continuous running suture were used in 10 patients (group 1), the appropriate size of anastomosis in which venous incision limited within the common pulmonary vein and the continuous running suture used in 4 patients (group 2), and the appropriate size of anastomosis and the interrupted suture in 8 patients (group 3). PVOA were 3 (33%) in group 1, but 0 (0%) in group 2 and 3. Two late death occurred all in group 1 with PVOA. Cardiopulmonary bypass time and aortic clamp time in group 3 were 91 min and 74 min respectively, which did not become longer than those in both group 1 and group 2. Interrupted suture technique does not make operating time longer than continuous running suture one. PVOA is one of the important factors predicting late operative result.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
65.
A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency.  相似文献   
66.
67.
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.  相似文献   
68.
Heterotopic heart transplantation: a radiographic review   总被引:1,自引:0,他引:1  
Heterotopic heart transplantation can be performed in the presence of high pulmonary vascular resistance. The authors call attention to a rare, but potentially life-saving procedure.  相似文献   
69.
The authors performed a study of intraocular pressure-dependent changes in optic disc cupping in 17 adults with chronic open-angle glaucoma. Analyses with the Rodenstock Optic Nerve Head Analyzer were performed at baseline low intraocular pressure during therapy, after elevation of intraocular pressure (from therapeutic failure or noncompliance), and after reduction of intraocular pressure with successful therapy. Optic disc cupping increased significantly upon short-term increase of intraocular pressure from baseline of 20.4 +/- 2.5 mmHg to 31.1 +/- 5.9 mmHg. Optic disc cupping reverted to baseline after persistent intraocular pressure reduction to 19.3 +/- 4.8 mmHg. These data demonstrate intraocular pressure-dependent dynamic changes of optic disc cupping in patients with demonstrable glaucomatous optic nerve damage. They underscore the detrimental effect of elevated intraocular pressure and the beneficial effect of intraocular pressure reduction on optic disc cup changes.  相似文献   
70.
The relation between smoking and risk of asthma has been well-examined; however little attention has been paid to the correlation between smoking and asthma symptoms. The aims of this study were to examine respiratory symptoms in asthmatics with a highly prevalent use of inhaled corticosteroid (ICS) and to assess the effects of smoking and its cessation. A cross-sectional study of pulmonologist-based 3197 asthmatics (men 45.2%, ages 20-97) was performed using a questionnaire about smoking habits, the incidence and frequency of symptoms (sputum, cough and wheezing, night symptoms, and shortness of breath), physical activity interference, and medication. Although 81.4% of the patients used ICS according to the international guideline, 14.9% had activity interference, and daily symptoms remained in 43.3%. At the time of the questionnaire, 21.6% were current and 25.1% were ex-smokers. In multiple logistic regression analysis, the factors of significance (p < 0.0001) were (1) smoking; for all four symptoms, (2) age and duration of asthma; for shortness of breath. Current smokers were at a risk of sputum (age-adjusted odds ratio 2.32 [95% confidence interval 1.73-3.11]; 2.09 [1.57-2.79]), of cough and wheezing (2.38 [1.81-3.14]; 1.78 [1.35-2.36]), of night symptoms (1.95 [1.41-2.60]; 1.47 [1.09-1.98]), and of shortness of breath (1.70 [1.26-2.28]; 1.30 [0.97-1.75]) in men and women, respectively. These ratios in ex-smokers decreased to the level similar to nonsmokers. Although 81.4% of asthmatic patients used ICS, 43.3% complained of daily respiratory symptoms, especially sputum. It is suggested that the effects of ICS on asthma symptoms may be interfered with by smoking and therefore more emphasis should be placed on cessation of smoking.  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