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   22430篇
  免费   1645篇
  国内免费   36篇
耳鼻咽喉   225篇
儿科学   877篇
妇产科学   587篇
基础医学   3040篇
口腔科学   652篇
临床医学   2567篇
内科学   4341篇
皮肤病学   310篇
神经病学   1808篇
特种医学   873篇
外科学   3063篇
综合类   375篇
一般理论   43篇
预防医学   2146篇
眼科学   342篇
药学   1395篇
  1篇
中国医学   16篇
肿瘤学   1450篇
  2022年   143篇
  2021年   329篇
  2020年   231篇
  2019年   361篇
  2018年   399篇
  2017年   331篇
  2016年   335篇
  2015年   418篇
  2014年   576篇
  2013年   764篇
  2012年   1115篇
  2011年   1208篇
  2010年   645篇
  2009年   545篇
  2008年   1077篇
  2007年   1170篇
  2006年   1095篇
  2005年   1082篇
  2004年   951篇
  2003年   945篇
  2002年   812篇
  2001年   634篇
  2000年   625篇
  1999年   517篇
  1998年   234篇
  1997年   201篇
  1996年   205篇
  1995年   214篇
  1994年   194篇
  1993年   173篇
  1992年   468篇
  1991年   454篇
  1990年   433篇
  1989年   430篇
  1988年   396篇
  1987年   353篇
  1986年   305篇
  1985年   376篇
  1984年   287篇
  1983年   260篇
  1982年   160篇
  1979年   211篇
  1978年   182篇
  1977年   150篇
  1976年   146篇
  1975年   157篇
  1974年   158篇
  1973年   197篇
  1972年   159篇
  1971年   142篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
A comparison of motor unit behaviour in young and aged subjects   总被引:1,自引:0,他引:1  
We evaluated motor unit behaviour in young and aged subjects during ramped tension development and release to 10% maximum voluntary contraction requiring 10 seconds to complete. Six young and six elderly adults performed isometric abductor digiti minimi muscle contractions while motor units were recorded with implanted fine wire electrodes. Computer interactive programs yielded interspike interval (ISI) data for 16 units from the young and for 15 units from the aged subjects. Mean ISIs for young were 88.4 ms for shortening and 96.5 ms for lengthening contractions. Units from the aged had ISIs of 110.5 ms and 117.1 ms for shortening and lengthening contractions. Some evidence for between-group differences in firing pattern during ascending and descending ramps was also found.  相似文献   
72.
73.
Acid phosphatases   总被引:1,自引:0,他引:1  
  相似文献   
74.
Identification of symptoms that are directly responsive to neuroleptic drugs at progressive phases of treatment is important for monitoring drug response and understanding the relationship between neurochemical mechanisms of drug action and disordered behavior. Using multiple regression analyses that controlled for pretreatment severity, we identified those symptoms that improved in direct relation to serum concentrations of perphenazine after 10 days of treatment. Improvement in two positive symptoms of psychosis--hallucinations and conceptual disorganization--appears to be related to perphenazine level and useful for assessment of early drug response.  相似文献   
75.
Pollen patterns were compared between Vail, CO (8,200 feet elevation), Aspen, CO (7,900 feet) and Denver, CO (5,280 feet) from 1984 through 1988. Counts were obtained at all sites with a volumetric intermittent cycling rotating impaction sampler. Aspen and Denver were compared in 1984, and Vail and Denver from 1985 through 1988. While counts were generally lower in the mountain sites than Denver, certain pollens, especially trees, were quite high. Ragweed was essentially absent from Aspen and Vail, and chenopod-amaranth counts were very low. Cedar, pine, and aspen frequently pollinated despite active snowfall.  相似文献   
76.
MR imaging of neurocysticercosis   总被引:1,自引:0,他引:1  
Magnetic resonance (MR) was performed in 50 patients with neurocysticercosis. Comparison was made with other neuroradiological imaging modalities including CT, myelography, CT ventriculography, and CT myelocisternography. Eighteen patients were found to have intraventricular cysts. In several patients, these were multiple and 22 intraventricular cysts were discovered. Although 4 of the 22 ventricular cysts were missed by MR, T1-weighted images can play a significant role in the early detection of intraventricular cysticercosis cysts, showing the cyst wall (9 of 22), a high intensity mural nodule (6 of 22), and increased signal intensity of the cyst fluid (5 of 22). Cisternal cysts (14 cysts in 10 patients) could be identified; they appear similar to intraventricular cysts, but mural nodules are infrequently seen (1 of 14). Twenty-nine patients had 69 parenchymal cysts. An attempt was made to assess the viability of these parenchymal lesions by matching the CT and MR findings with the Escobar pathologic staging system. Neuroimaging findings seemed compatible with early parenchymal lesions in the vesicular stage in 11 instances. Findings in cases with later stage cysts tend to support the concept that a dying larva provokes pronounced inflammatory reaction in the adjacent brain. Computed tomography remains the superior modality for depicting parenchymal calcifications within dead larvae. A case of a spinal cysticercosis cyst demonstrated with MR (in a patient with extensive intracranial cisternal cysts and a fourth ventricular cyst) is described.  相似文献   
77.
The authors previously described a method of windowing the femur that allowed good exposure for femoral cement removal and provided for reconstruction of the defect. Since that report, they have developed instrumentation to facilitate windowing of the femoral shaft. They describe its use in this report.  相似文献   
78.
Kearns-Sayre syndrome with sideroblastic anemia: molecular investigations.   总被引:2,自引:0,他引:2  
The progressive syndrome of Kearns-Sayre has been studied at the clinical, biochemical and genetic levels in a patient. Clinical arguments suggest an evolution from Pearson's disease to Kearns-Sayre syndrome. The respiratory chain activities were low, and Southern blot analysis, together with gene sequencing, showed a heteroplasmic deletion of 7767 base pairs in a significant proportion of the mitochondrial DNA in different tissues. Protein synthesis studies on lymphoblasts did not reveal any translation of the new reading frame created by the deletion, although the corresponding deleted mitochondrial DNA sequence is transcribed.  相似文献   
79.
Meningiomas have been reported following radiation of the head, usually with a long latent interval between exposure and the diagnosis of the new tumor. We report a benign meningioma resected approximately 3 1/2 years after radiation therapy for a glioma, which represents an unusually short latent interval between radiation and new tumor growth.  相似文献   
80.
By focusing on quality of life through education and ongoing support, the pulmonary rehabilitation staff at Little Company of Mary Hospital in Torrance, Calif, gives hope to respiratory patients and teaches them to become partners in the management of their disease.  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