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   4804篇
  免费   291篇
  国内免费   14篇
耳鼻咽喉   35篇
儿科学   136篇
妇产科学   77篇
基础医学   634篇
口腔科学   93篇
临床医学   300篇
内科学   1078篇
皮肤病学   59篇
神经病学   294篇
特种医学   182篇
外科学   860篇
综合类   16篇
预防医学   179篇
眼科学   346篇
药学   300篇
中国医学   3篇
肿瘤学   517篇
  2023年   29篇
  2022年   43篇
  2021年   73篇
  2020年   44篇
  2019年   68篇
  2018年   109篇
  2017年   78篇
  2016年   107篇
  2015年   84篇
  2014年   112篇
  2013年   145篇
  2012年   219篇
  2011年   217篇
  2010年   115篇
  2009年   98篇
  2008年   172篇
  2007年   191篇
  2006年   180篇
  2005年   197篇
  2004年   202篇
  2003年   180篇
  2002年   193篇
  2001年   158篇
  2000年   171篇
  1999年   145篇
  1998年   63篇
  1997年   37篇
  1996年   59篇
  1995年   44篇
  1994年   41篇
  1993年   33篇
  1992年   146篇
  1991年   131篇
  1990年   111篇
  1989年   139篇
  1988年   131篇
  1987年   113篇
  1986年   103篇
  1985年   84篇
  1984年   54篇
  1983年   54篇
  1982年   31篇
  1980年   25篇
  1979年   37篇
  1976年   26篇
  1972年   27篇
  1971年   25篇
  1970年   25篇
  1967年   23篇
  1966年   28篇
排序方式: 共有5109条查询结果,搜索用时 15 毫秒
51.
A 65-year-old woman with liver metastases from colon cancer and tumor thrombus extending from the right hepatic vein (HV) to the right atrium (RA) presented with marked lower-extremity edema and massive ascites. Computed tomography showed tumor thrombus completely occluding the inferior vena cava (IVC) and HV ostia. Recanalization of the IVC and HVs was performed. Metallic stents were placed in tandem from the superior vena cava to the IVC through the RA, and additional metallic stents were placed in the left HV. The patient's symptoms were relieved, and there was no recurrence of these symptoms for 19.5 months until death.  相似文献   
52.
53.
PURPOSE: We recently reported a protective role of clusterin expression against apoptosis induced by a wide variety of stimuli in several human cancer models. In the current study we tested the hypothesis that clusterin over expression confers a benefit for the metastasis of renal cell carcinoma through the inhibition of apoptosis induced by the various obstacles the cancer cells may confront after detachment from their primary origin. MATERIALS AND METHODS: We introduced clusterin complementary DNA into human renal cell carcinoma ACHN cells, which do not express detectable level of clusterin expression, and generated the clusterin over expressing cell line ACHN/CL and the control vector only transfected cell line ACHN/C. In vitro anti-cell death activity under anchorage independent conditions among ACHN sublines was examined by limiting dilution assay and cell survival assay in suspension. To investigate the in vivo effects of clusterin over expression on metastatic potentials each cell line was injected into the tail vein or renal subcapsule of nonobese diabetic, severe combined immunodeficient mice and the metastatic features in all abdominal and thoracic organs were evaluated. RESULTS: ACHN/CL showed significantly enhanced growth in limiting dilution cultures compared with ACHN/C. The analysis of cell survival in the floating assay also revealed that ACHN/CL had a powerful survival advantage in suspension compared with ACHN/C. Furthermore, ACHN/CL formed more than 5-fold as many metastatic nodules in the lung after intravenous injection than ACHN/C. Similarly more marked lung metastasis was observed after implanting ACHN/CL cells into the renal subcapsule than after implanting ACHN/C cells. In contrast, there were no significant differences among ACHN sublines in the growth rates in vitro and in vivo, cell motility or invasive ability. CONCLUSIONS: These findings suggest that, if clusterin is over expressed, it prolongs cell survival under unfavorable conditions in the metastatic process, resulting in the enhanced metastatic potential of renal cell carcinoma.  相似文献   
54.
The objective of this study was to evaluate the expression levels of multiple potential molecular markers in prostate cancer to clarify the significance of these markers as prognostic indicators in patients undergoing radical prostatectomy (RP). This study included a total of 193 patients with clinically organ-confined prostate cancer who underwent RP without any neoadjuvant therapies. Expression levels of 12 proteins, including Ki-67, p53, androgen receptor (AR), matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor, Aurora-A, Bcl-2, clusterin, heat shock protein 27 (HSP27), HSP70, and HSP90, in RP specimens obtained from these 193 patients were measured by immunohistochemical staining. Of the 12 molecules, Ki-67, p53, AR, MMP-2, MMP-9, and HSP27 expression were significantly associated with several conventional prognostic factors. Univariate analysis identified these 6 markers as significant predictors for biochemical recurrence as well, while prostate-specific antigen, Gleason score, seminal vesicle invasion (SVI), surgical margin status (SMS), lymph node metastasis, and tumor volume were also significant. Of these significant factors, Ki-67 expression, SVI, and SMS appeared to be independently related to biochemical recurrence by multivariate analysis. Furthermore, there were significant differences in biochemical recurrence-free survival according to positive numbers of these three independent risk factors. These findings suggest that consideration of expression levels of potential molecular markers in RP specimens, in addition to conventional prognostic parameters, would contribute to accurate prediction of biochemical recurrence following RP in patients with clinically localized prostate cancer, and that combined evaluation of Ki-67 expression, SVI, and SMS would be particularly useful for further refinement of the system in predicting biochemical outcome.  相似文献   
55.
Acute subdural hematoma (ASDH) is a critical condition following the onset of traumatic brain injury, and it is essential to immediately reduce elevated intracranial pressure (ICP). Single burr hole surgery/twist drill craniostomy is commonly performed in patients with ASDH as an emergency surgical intervention, usually preceding decompressive craniotomy. A novel method using a cerebrospinal fluid (CSF) drainage catheter kit for rapid drainage of ASDH is described. Percutaneous twist drill craniostomy using a CAMINO(?) micro ventricular bolt pressure-temperature monitoring kit was performed in the emergency room in 12 patients with severe ASDH. The kit contained a closed-system CSF drainage and pressure-temperature monitoring catheter, which allowed aspiration of the hematoma and monitoring of the ICP. The tip of the catheter was inserted into the hematoma from the forehead. The mean initial ICP was 61 mmHg, with a range of 31 to 120 mmHg. The liquid hematoma was aspirated, and the ICP was temporarily controlled to the normal range. Pupil dilation recovered immediately after aspiration of the hematoma in 3 patients. No complications occurred either during or after the operation. This new method for craniostomy is easy, safe, and effective to monitor and rapidly control ICP in the emergency room. This technique also offers the possibility of evaluating the patient's prognosis and determining indications for further decompressive craniectomy by the continuation of ICP control under ICP monitoring and evaluation of the reversibility of pupillary findings in ASDH patients.  相似文献   
56.
Ondine's curse is an uncommon type of sleep apnea syndrome characterized by failure of automatic respiration. We present an adult patient with brainstem glioma who presented with snoring and Ondine's curse as the only symptoms. CASE REPORT: A 52-year-old female was brought to the hospital by a fellow resident due to exceptionally loud snoring. During the hospitalization, Ondine's curse was diagnosed after monitoring using Apnomonitor 5 (Chest Co., Tokyo), a cheap, non-invasive respiratory monitoring procedure. MRI and MR spectroscopy revealed a brainstem glioma. After radiation therapy, clinical response was documented using repeat apnomonitoring. CONCLUSION: Exceptionally loud snoring in non-obese adult patients with sleep apnea may be an early feature of a brainstem space-occupying lesion. Overnight sleep respiratory evaluation and neuroimaging should be considered in such instances.  相似文献   
57.
Extraadrenal abnormal uptake on adrenocortical scintigraphy has been reported rarely in the normal gallbladder, lipid cell tumor of the ovary, or in clear cell type renal cell carcinoma. Clear cell type renal cell carcinoma contains glycogen and cholesterol like the adrenal gland, but the uptake of the radionuclide I-131 cholesterol has been reported to be low and not sufficient to image it. Right renal and adrenal masses were incidentally discovered on abdominal CT scan in a patient with chronic renal failure resulting in bilateral acquired cystic kidney disease. Adrenocortical scintigraphy done to know the nature of the adrenal mass showed high uptake corresponding to the right renal mass and the right adrenal mass. Clear cell type renal cell carcinoma and adrenal adenoma with prominent clear cells were histologically confirmed on hematoxylin-eosin stain and in an immunohistochemical study with renal cell antibody. Not only low-density lipoprotein receptors mediated uptake but also overall replacement of the right non-tumorous renal parenchyma by acquired cysts may have played a role in imaging the renal cell carcinoma on adrenocortical scintigraphy.  相似文献   
58.
Cui W  Hosaka N  Miyake T  Wang X  Guo K  Cui Y  Li Q  Song C  Feng W  Li Q  Takaki T  Nishida T  Inaba M  Ikehara S 《Transplantation》2008,85(8):1151-1158
BACKGROUND: Although bone marrow transplantation (BMT) has become a valuable strategy for the treatment of various intractable diseases in recent years, success rates remain low in elderly patients because of low thymic function. We have previously shown that fetal thymus transplantation (TT) with BMT is effective for elderly recipients in mice. METHODS: We performed fully major histocompatibility complex (MHC)-mismatched fetal TT from B6 (H-2) mice plus allogeneic BMT from C3H/HeN (H-2) mice by intra-bone marrow-BMT (IBM-BMT) using congenitally athymic nude (nu/nu) BALB/c (H-2), or BALB/c adult-thymectomized recipients to obtain triple chimeras. We next carried out the IBM-BMT+TT using senescence-accelerated mouse P1 strain (SAMP1) to examine whether this method would be applicable to aging mice. RESULTS: Triple chimeric mice survived for a long period with sufficient T-cell functions comparable to the mice treated with BMT plus MHC-matched TT, whereas those without TT survived for a short period with insufficient T-cell reconstitution. Almost all the hematolymphoid cells were derived from donor bone marrow cells. Interestingly, they showed tolerance to all three types of MHC determinants with donor-derived thymic dendritic cells in TT. Triple chimeric SAMP1 also survived for long periods with T-cell functions restored in contrast to non-TT SAMP1 recipients. CONCLUSION: These findings suggest that third party combined TT with allogeneic IBM-BMT may be more advantageous for elderly recipients with low thymic function, than IBM-BMT alone (without TT).  相似文献   
59.
A 72-year-old man was admitted to another hospital because of general fatigue and dyspnea secondary to renal insufficiency. Abdominal computed tomography (CT) and magnetic resonance imaging showed left atrophic kidney, right hydronephrosis, and an intra-pelvic mass of soft-tissue density located anterior to the sacrum, involving the right ureter at the level between the 5th lumber vertebra and the sacrum. He was referred to our hospital after percutaneous nephrostomy was constructed into right kidney. CT-guided needle biopsy revealed the idiopathic retroperitoneal fibrosis, leading us to give him steroid therapy. Three weeks later, radiographic findings showed a remarkable reduction of the mass and the improvement of the right ureteral stricture.  相似文献   
60.
Role of percutaneous image-guided biopsy in the evaluation of renal masses   总被引:1,自引:0,他引:1  
OBJECTIVE: The objective of the present study was to evaluate the indications, accuracy, complications and impact of image-guided percutaneous biopsy of renal masses. MATERIALS AND METHODS: Between 1994 and 1999, percutaneous biopsies under ultrasonography or computerized tomography guidance were performed in 33 patients with renal mass (22 men and 11 women, mean age 57.5 years, range 21-88). We retrospectively analyzed the relationship between clinical and histopathological findings, and discuss the appropriateness of the indications for image-guided percutaneous biopsy in the diagnosis of renal masses. RESULTS: The indications used in our institution were as follows: (1) clinical and radiological findings to suggest a diagnosis other than primary renal cell carcinoma (RCC) (n = 15); (2) suspicious lesions of RCC in multiple cystic renal masses (n = 7); (3) differentiation of transitional cell carcinoma of the renal pelvis from RCC (n = 7); (4) differentiation of angiomyolipoma from RCC (n = 4). Sufficient amounts of tissues were obtained from all patients for pathological diagnosis. Among 33 patients, 21 (63.6%) were diagnosed positive for malignancy, and 15 underwent surgical intervention. The histopathological findings between percutaneous biopsy and surgically resected tissue were identical in 13 cases (86.7%). No patient developed major complications requiring surgical treatment. CONCLUSION: If performed under appropriate selection of patients, percutaneous image-guided biopsy is a safe, reliable and accurate method of managing suspicious and/or indeterminate renal mass, and may contribute to the selection of appropriate clinical management by avoiding unnecessary procedures.  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