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   208424篇
  免费   3071篇
  国内免费   160篇
耳鼻咽喉   1604篇
儿科学   7404篇
妇产科学   3602篇
基础医学   20452篇
口腔科学   2179篇
临床医学   15539篇
内科学   38714篇
皮肤病学   1061篇
神经病学   19555篇
特种医学   10227篇
外国民族医学   1篇
外科学   34669篇
综合类   2521篇
一般理论   18篇
预防医学   19987篇
眼科学   3175篇
药学   11350篇
中国医学   668篇
肿瘤学   18929篇
  2023年   185篇
  2022年   316篇
  2021年   891篇
  2020年   544篇
  2019年   893篇
  2018年   22866篇
  2017年   18009篇
  2016年   20132篇
  2015年   1786篇
  2014年   2114篇
  2013年   2538篇
  2012年   9516篇
  2011年   23639篇
  2010年   20308篇
  2009年   12952篇
  2008年   21754篇
  2007年   24071篇
  2006年   2891篇
  2005年   4430篇
  2004年   5401篇
  2003年   6232篇
  2002年   4191篇
  2001年   526篇
  2000年   564篇
  1999年   389篇
  1998年   580篇
  1997年   505篇
  1996年   305篇
  1995年   319篇
  1994年   275篇
  1993年   231篇
  1992年   131篇
  1991年   192篇
  1990年   207篇
  1989年   151篇
  1988年   110篇
  1987年   95篇
  1986年   80篇
  1985年   97篇
  1984年   105篇
  1983年   108篇
  1982年   108篇
  1981年   80篇
  1980年   105篇
  1979年   39篇
  1978年   45篇
  1974年   42篇
  1938年   60篇
  1932年   57篇
  1930年   47篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
72.
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   
73.
74.
75.
76.
77.
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   
78.
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   
79.
PURPOSE: To analyze the effectiveness of surgery and chemotherapy with or without radiotherapy in the management of limited small cell lung cancer (LSCLC) in stages I and II. PATIENTS AND METHODS: 39 patients (median age 62 years) with LSCLC in stages pT1 or pT2 and pN0 or pN1 (stages IA-IIB) who had a tumor resection and systematic lymph node dissection were reviewed retrospectively. The median follow-up period was 29 months. 35 patients (90%) received a median of four cycles of a platinum-containing chemotherapy postoperatively. 16 patients (41%) received an adjuvant thoracic radiotherapy (TRT, median 50 Gy); 21 patients (54%) received a prophylactic cranial irradiation (PCI, median 30 Gy). RESULTS: The median overall survival for all patients was 47 months, resulting in actuarial 1-, 3-, and 5-year survival rates of 97%, 58%, and 49%, respectively. Distant metastases were found in 13 patients (33%) after a median of 16 months. Patients who received an adjuvant TRT showed a trend toward improved thoracic recurrence-free survival (p = 0.06) and improved overall survival (p = 0.07) compared to those treated with surgery and chemotherapy only. Brain metastasis-free survival (p = 0.01) and overall survival (p = 0.01) were improved significantly in patients who received a PCI. CONCLUSION: Surgical tumor resection may be considered for carefully selected patients. Adjuvant chemotherapy and PCI are recommended for all patients. Adjuvant TRT is currently used in patients with positive lymph nodes (pN1), because the probability of a subclinical involvement of the mediastinal lymphatic system appears to be increased in these patients.  相似文献   
80.
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   
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