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   6406篇
  免费   276篇
  国内免费   36篇
耳鼻咽喉   28篇
儿科学   82篇
妇产科学   53篇
基础医学   701篇
口腔科学   316篇
临床医学   394篇
内科学   1836篇
皮肤病学   129篇
神经病学   417篇
特种医学   231篇
外科学   1021篇
综合类   22篇
一般理论   1篇
预防医学   168篇
眼科学   165篇
药学   463篇
中国医学   5篇
肿瘤学   686篇
  2023年   34篇
  2022年   72篇
  2021年   140篇
  2020年   65篇
  2019年   96篇
  2018年   114篇
  2017年   91篇
  2016年   108篇
  2015年   114篇
  2014年   142篇
  2013年   188篇
  2012年   321篇
  2011年   330篇
  2010年   171篇
  2009年   174篇
  2008年   301篇
  2007年   323篇
  2006年   323篇
  2005年   324篇
  2004年   285篇
  2003年   279篇
  2002年   308篇
  2001年   221篇
  2000年   229篇
  1999年   183篇
  1998年   97篇
  1997年   50篇
  1996年   50篇
  1995年   52篇
  1994年   57篇
  1993年   45篇
  1992年   116篇
  1991年   108篇
  1990年   108篇
  1989年   131篇
  1988年   99篇
  1987年   98篇
  1986年   85篇
  1985年   91篇
  1984年   84篇
  1983年   52篇
  1982年   25篇
  1981年   32篇
  1980年   35篇
  1979年   46篇
  1978年   32篇
  1970年   25篇
  1968年   37篇
  1967年   26篇
  1966年   24篇
排序方式: 共有6718条查询结果,搜索用时 15 毫秒
1.
We describe our methods and outcomes of multidisciplinary treatments in patients with unresectable hilar cholangiocarcinoma. Fifty‐seven patients with a known outcome were enrolled. Thirty‐four of 57 patients were treated and evaluated by salvage therapy. For salvage therapy, we used internal and external radiotherapy, photodynamic therapy, YAG laser therapy and microwave coagulation therapy. The median survival time was 548 days for the group receiving salvage therapy and 198 days for the group not receiving this treatment. In conclusion, although no randomization of the patients was performed in this retrospective study, our present data provide convincing evidence that salvage therapy is a useful therapeutic approach for unresectable hilar cholangiocarcinomas.  相似文献   
2.
Abstract: Intravenous injection of gadolinium chloride (GdCl3) at a dose of 10 mg/kg caused an increase in proliferating cell nuclear antigen labeling index and the grade of pyronin positivity (RNA level) in rat liver. In CCl4-exposed rats, pretreatment with GdCl3 also showed a preventive effect of the liver injury both biochemically and histologically. Moreover, the proliferative action preceded the attenuative effect of the liver injury. Results suggest that GdCl3 induces hepatocyte proliferation, and this action of GdCl3 may modify the development of CCl4-induced liver injury.  相似文献   
3.
In lung cancer patients, hypercalcemia is a fairly common metabolic problem associated with malignancy. However, the occurrence of hypercalcemia in lung cancer patients means an ominous prognostic sign. As hypercalcemia often causes early death, quick diagnosis and treatment for hypercalcemia are required. A 69-year-old woman was admitted to our hospital with anorexia caused by hypercalcemia. On admission, serum level of PTH was elevated and PTHrP was normal. From the results of CT findings and transbronchial lung biopsy, the cause of the hypercalcemia was determined as lung cancer incidentally complicated with primary hyperparathyroidism. First, serum calcium level was returned to normal through hydration with saline and bisphosphonates. Next, left hemithyroidectomy for primary hyperparathyroidism was performed. Histologically, the tumor was diagnosed as parathyroid adenoma. Fifteen days later, left lower lobectomy for primary lung cancer was performed under a video-assisted thoracoscopic approach. Histologically, the tumor was diagnosed as a moderately differentiated adenocarcinoma. Four years and three months after the operation, the patient is alive and well with no sign of recurrence. When a lung cancer patient is complicated with hypercalcemia, we need to consider that primary hyperparathyroidism is a possible cause of the hypercalcemia.  相似文献   
4.
We report 51- and 43-year-old Japanese female patients with systemic lupus erythematosus (SLE) associated with subarachnoid hemorrhage (SAH) due to rupture of intracranial saccular aneurysms. We also review the literature of Japanese SLE patients with SAH. SAH in Japanese SLE patients is more frequent than in patients from Western countries, has different features from the general population, and can occur regardless of SLE disease activity. Clinicians must pay attention to SAH in all SLE patients.  相似文献   
5.
To clarify when and how rapidly individual muscles are damaged in the course of Duchenne muscular dystrophy (DMD), we followed X-ray CT of whole body skeletal muscles from 29 cases of DMD patients (age ranging 3 to 23 years) for a period of 2 to 6 years. Each patient had 2 to 5 scans with an average of 3.3. We evaluated chronological changes of 23 muscles from the entire body using the muscle damage stage defined as follows. The stages were classified into the following 5 stages: stage 0; normal, 1; area of fatty replacement less than 10% of whole muscle area, 2; area of fatty replacement between 10 to 50%, 3; area of fatty replacement 50 to 90%, 4; almost complete fatty replacement. Each muscle had its own period of rapid degeneration starting at 5 to 10 years of age and, continuing 5 to 10 years. In some muscles such as gluteus maximus or quadriceps femoris, fatty replacement started at 5 years or earlier and progressed for five years, while other muscles such as splenius capitis, damage started much later, e.g. around 10 years of age and the progression was much slower. There was a variation of at least 5 years among individual patients in any muscle damage stage, reflecting the variability of clinical severity in each patient. On the basis of the above results we defined the whole body muscle damage index as a summation of the muscle damage stages of the following five muscles: gluteus maximus, quadriceps femoris, gracilis, medial head of gastrocnemius and splenius capitis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
6.
The purpose of this study was to evaluate the effects of pegfilgrastim, a long-acting granulocyte colony-stimulating factor, on the normal biodistribution of (18)F-FDG in an animal model and in humans. METHODS: Two groups of 12 rats received a single subcutaneous injection of either normal saline or pegfilgrastim. One, 7, 14, and 21 d after injection, biodistribution studies were performed 1 h after (18)F-FDG injection. Sixteen breast cancer patients underwent baseline (18)F-FDG PET/CT and, approximately 1 wk after receiving 1 dose of docetaxel and adjunctive pegfilgrastim, follow-up (18)F-FDG PET/CT (scan 2). Standardized uptake values corrected for lean body mass (SUL) were determined for several normal organs before and after therapy. RESULTS: In rats, bone marrow (18)F-FDG uptake (standardized uptake value) was higher in the pegfilgrastim group 1 d after injection (mean +/- SD, 8.3 +/- 4.1 vs. 2.5 +/- 0.2, P < 0.05), whereas (18)F-FDG uptake in blood was lower (0.41 +/- 0.06 vs. 0.49 +/- 0.01, P < 0.05). In patients, mean SUL was higher in bone marrow (4.49 +/- 1.50 vs. 1.33 +/- 0.22, P < 0.0001), spleen (3.29 +/- 0.83 vs. 1.23 +/- 0.23, P < 0.0001), and liver (1.45 +/- 0.25 vs. 1.31 +/- 0.23, P = 0.01) but lower in brain (4.18 +/- 0.76 vs. 5.14 +/- 1.44, P < 0.01) on scan 2 than on the baseline scan. CONCLUSION: In both the animal model and humans, pegfilgrastim markedly increased bone marrow uptake of (18)F-FDG and reduced (18)F-FDG uptake in some normal tissues. These profound alterations in (18)F-FDG biodistribution induced by pegfilgrastim must be considered when one is evaluating quantitative (18)F-FDG PET scans for tumor response to therapy.  相似文献   
7.
OBJECTIVES: Bronchiolitis obliterans (BO) is the main cause of late mortality among long-term survivors of lung transplantation. Chemokine-chemokine receptor (CCR) interaction and subsequent recruitment of infiltrating cells to the graft are early events in the development of chronic rejection of transplanted lungs. The present study investigated whether blockade of chemokine receptors CCR1 and CCR5 with Met-regulated-on-activation, normal T cells expressed and secreted (RANTES), an amino-terminal modified derivative of RANTES/CCL5, affects the development of BO in murine model and we sought to determine the expression of RANTES/CCL5 and their relationship with extracellular signal-regulated kinase (ERK). Materials and Methods: BALB/c mouse tracheas were heterotopically transplanted into C57Black6 recipients and treated for 21 days with either Met-RANTES at 20 microg/day or vehicle. Animals were killed at 21 days after transplantation for histologic examination of ERK expression. RESULTS: RANTES/CCL5 was highly expressed in allografts compare to isografts. Met-RANTES treatment ameliorated fibrous airway obliteration in a mouse model of BO and decreased ERK expression. CONCLUSION: Blockade of chemokine receptors by Met-RANTES ameliorated airway obliteration and decreased ERK expression. These findings suggest that chemokine receptors CCR1 and CCR5 play significant roles in the development of chronic rejection and ERK may be a new molecular target for chronic rejection.  相似文献   
8.
Neuronavigation has become an effective therapeutic modality and is used routinely for intra-axial tumor removal. This retrospective study was conducted to evaluate the clinical impact of neuronavigation and image-guided extensive resection for adult patients with supratentorial malignant astrocytomas. Between 1990 and 2002, 76 adult patients with pathologically confirmed malignant astrocytomas underwent craniotomy and removal of the tumors at the Toyama Medical and Pharmaceutical University Hospital. Of these 76 patients, 42 were treated using neuronavigation with conventional microneurosurgery and the other 34 were treated with conventional microneurosurgery alone. Postoperative early MRI with contrast enhancement was done, and gross total resection was defined as the complete absence of residual tumor. Survival time was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from the Cox proportional hazards model. In univariate analysis, age (< 65), grade 3, preoperative KPS (>/= 80), use of neuronavigation, and gross total resection were significantly associated with longer survival. However, when the data were submitted to multivariate analysis, grade 3, preoperative KPS (>/= 80), and gross total resection were independent prognostic factors. The median survival periods of patients receiving gross total resection (vs. partial resection) and neuronavigation (vs. no neuronavigation) were 16 (vs. 9) months and 16 (vs. 10) months, respectively. The percentage of a gross total resection was significantly higher in the neuronavigation group compared to that in the no-navigation group (64.3 % vs. 38.2 %, p < 0.05). Neurological deterioration occurred in 4 of 42 (9.5 %) and in 6 of 34 (17.6 %) patients after surgery with neuronavigation and surgery without neuronavigation, respectively, although this difference was not statistically significant. Our results showed that neuronavigation increases the radicality in the resection of malignant astrocytomas and is objectively useful for improving survival time.  相似文献   
9.
10.
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