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   184147篇
  免费   1580篇
  国内免费   60篇
耳鼻咽喉   1186篇
儿科学   6844篇
妇产科学   3143篇
基础医学   17421篇
口腔科学   1723篇
临床医学   13116篇
内科学   33000篇
皮肤病学   802篇
神经病学   17585篇
特种医学   9173篇
外科学   30398篇
综合类   2331篇
一般理论   1篇
预防医学   18522篇
眼科学   2941篇
药学   9906篇
中国医学   643篇
肿瘤学   17052篇
  2023年   122篇
  2022年   183篇
  2021年   449篇
  2020年   257篇
  2019年   356篇
  2018年   22217篇
  2017年   17567篇
  2016年   19743篇
  2015年   1195篇
  2014年   1231篇
  2013年   1283篇
  2012年   7707篇
  2011年   21678篇
  2010年   19165篇
  2009年   11859篇
  2008年   19998篇
  2007年   22184篇
  2006年   1068篇
  2005年   2605篇
  2004年   3767篇
  2003年   4683篇
  2002年   2786篇
  2001年   371篇
  2000年   512篇
  1999年   272篇
  1998年   242篇
  1997年   242篇
  1996年   144篇
  1995年   137篇
  1994年   133篇
  1993年   87篇
  1992年   105篇
  1991年   152篇
  1990年   163篇
  1989年   124篇
  1988年   83篇
  1987年   59篇
  1986年   55篇
  1985年   52篇
  1984年   52篇
  1983年   42篇
  1982年   42篇
  1980年   51篇
  1974年   31篇
  1969年   23篇
  1938年   60篇
  1937年   27篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 960 毫秒
61.
Objective: To study the diagnostic value of T2^*-weighted first-pass perfusion imaging in breast tumors. Methods: We analyzed the magnetic resonance imaging (MRI) information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^*-weighted first-pass perfusion imaging. The curve's maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results: Malignant breast lesions showed higher maximal signal intensity drop rate (44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001) than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions (23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05). Conclusion: The T2^*-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis.  相似文献   
62.
63.
We report the clinical, neurophysiological (comprehending electromyography, nerve conduction velocities, and multimodal evoked potentials), histological study of the nerve and muscle and the effect of vitamin E supplement in a 32-year-old case with chronic vitamin E deficiency subsequent to acquired intestinal malabsorption. An early diagnosis for an early treatment is essential in preventing severe neurological deterioration.  相似文献   
64.
65.
66.
Abstract We report a case of SMV injury in a critically ill patient. The patient was a 19-year-old woman involved in a motor vehicle collision. Her injuries included grade II splenic and renal lacerations, devascularized and lacerated right and transverse colon, a transected transverse mesocolon, a massive shear injury of her abdominal wall, and two partial SMV transections. At initial damage control laparotomy, the SMV was ligated, the devascularized bowel resected and a temporary abdominal closure applied. At re-operation, a mesocaval shunt using saphenous vein was employed. The shunt failed and the patient required a saphenous vein jump graft. Although visceral vascular injuries are rare, ligation of the SMV in a damage control situation is acceptable. This case study is the first to discuss appropriate treatment when interruption to a patient's collateral visceral venous drainage limits the surgeon’s ability to ligate. In these situations, bypass shunts may be successful.  相似文献   
67.
OBJECTIVE: To verify whether immunohistochemistry might be useful in the distinction between a true laterocervical metastasis of an undetected thyroid carcinoma and a primary tumor outside the gland. DESIGN: Galectin-3, cytokeratin 19, and HBME-1 were assessed in six cases (group A) of laterocervical masses harboring papillary thyroid carcinoma (PTC) but without a thyroid tumor, and in eight cases (group B) showing PTC both in the thyroid and in the laterocervical masses. In both groups, normal-looking follicles adjacent to the laterocervical neoplasia were present. MAIN OUTCOME: We found that the apparently normal follicles in group A were negative for all the antibodies, while group B showed strong and diffuse positive immunostaining. The neoplastic areas were always positive for all the antibodies in both groups. CONCLUSION: Even if immunohistochemical patterns of residual follicles of group B are very well differentiated that they resemble normal thyroid parenchyma, they may well be metastatic carcinomas. On the contrary, the presence of morphologically and immunohistochemically normal-looking follicles in group A, with no intrathyroid tumor, suggests that the primary PTC might possibly develop in the ectopic thyroid tissue. In cases showing morphologically and immunohistochemically normal-looking follicles in laterocervical masses, these findings might lead to a reduction of the overdiagnosis of metastatic disease of an undetected carcinoma.  相似文献   
68.
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference.  相似文献   
69.
OBJECTIVES: This study sought to characterize epileptic phenotypes in children with nonspecific mitochondrial disease (MD) and to evaluate MD diagnostic approaches. METHODS: A retrospective analysis of the medical, electroencephalogram, and laboratory records of 142 patients with epilepsy was performed. The patients were evaluated for MD, and 124 patients were included in the final cohort. The MD criteria used included an oral glucose lactate stimulation test (OGLST) and urine organic acid/plasma amino acid (UOA/PAA) assays as metabolic indicators of modified Walker criteria, as suggested by Bernier et al. (Neurology 59:1406-1411, 2002). RESULTS: Twenty-two patients were classified as having definite MD (9), probable MD (5), possible MD (6), or pyruvate dehydrogenase (PDH) deficiency (3), including one patient which showed a respiratory chain (RC) defect and PDH deficiency. Seven out of eight patients in whom significant RC defects were observed showed complex I defects. In 14 patients, epileptic seizures start at infantile ages. Of 17 patients who substantially presented generalized seizures, 4 patients started with partial seizures. Five patients consistently presented only partial seizures. The OGLST and UOA/PAA assays were useful for a more precise diagnosis of MD, although low positive predictive value of the OGLST was regrettable. No patient was classified as definite MD by Walker's original criteria, but the use of our revised MD criteria resulted in the classification of nine additional patients as definite MD. CONCLUSIONS: MD manifested considerable diverse epileptic phenotypes and should be considered in the differential diagnosis of epilepsy in children with unexplained encephalomyopathy and progressive and fluctuating clinical courses.  相似文献   
70.
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