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   2570篇
  免费   178篇
  国内免费   18篇
耳鼻咽喉   21篇
儿科学   72篇
妇产科学   11篇
基础医学   333篇
口腔科学   63篇
临床医学   172篇
内科学   691篇
皮肤病学   45篇
神经病学   225篇
特种医学   88篇
外科学   428篇
综合类   7篇
一般理论   3篇
预防医学   89篇
眼科学   38篇
药学   160篇
中国医学   10篇
肿瘤学   310篇
  2023年   35篇
  2022年   27篇
  2021年   148篇
  2020年   69篇
  2019年   102篇
  2018年   107篇
  2017年   95篇
  2016年   95篇
  2015年   92篇
  2014年   106篇
  2013年   125篇
  2012年   172篇
  2011年   160篇
  2010年   116篇
  2009年   79篇
  2008年   125篇
  2007年   115篇
  2006年   125篇
  2005年   91篇
  2004年   90篇
  2003年   89篇
  2002年   68篇
  2001年   38篇
  2000年   40篇
  1999年   50篇
  1998年   15篇
  1997年   18篇
  1996年   11篇
  1995年   14篇
  1994年   14篇
  1993年   12篇
  1992年   31篇
  1991年   32篇
  1990年   27篇
  1989年   32篇
  1988年   21篇
  1987年   27篇
  1986年   16篇
  1985年   18篇
  1984年   14篇
  1983年   12篇
  1982年   8篇
  1979年   7篇
  1978年   5篇
  1977年   6篇
  1970年   5篇
  1969年   8篇
  1968年   7篇
  1967年   9篇
  1966年   5篇
排序方式: 共有2766条查询结果,搜索用时 312 毫秒
1.
2.

Background

There were few studies assessed the postoperative sarcopenia in patients with cancers. The objective of present study was to assess whether postoperative development of sarcopenia could predict a poor prognosis in patients with adenocarcinoma of esophagogastric junction, (AEG) and upper gastric cancer (UGC).

Methods

Patients with AEG and UGC who were judged as non-sarcopenic before surgery were reassessed the presence of postoperative development of sarcopenia 6 months after surgery. Patients were divided into the development group or non-development group, and clinicopathological factors and prognosis between these two groups were analyzed.

Results

The 5-year overall survival rates were significantly poorer in the development group than non-development group (68.0% vs. 92.6%, P?=?0.0118). Multivariate analyses showed that postoperative development of sarcopenia was an independent prognostic factor for poor overall survival (P?=?0.0237).

Conclusions

Postoperative development of sarcopenia was associated with a poor prognosis in patients with AEG and UGC.  相似文献   
3.
Tirabrutinib is a second‐generation Bruton’s tyrosine kinase inhibitor with greater selectivity than ibrutinib. Here, we conducted a multicenter, phase II study of tirabrutinib in patients with treatment‐naïve (Cohort A) or with relapsed/refractory (Cohort B) Waldenström’s macroglobulinemia (WM). Patients were treated with tirabrutinib 480 mg once daily. The primary endpoint was major response rate (MRR; ≥ partial response). Secondary endpoints included overall response rate (ORR; ≥ minor response), time to major response (TTMR), progression‐free survival (PFS), overall survival (OS), and safety. In total, 27 patients (18 in Cohort A; 9 in Cohort B) were enrolled. The median age was 71 y, and the median serum immunoglobulin M level was 3600 mg/dL. Among the patients, 96.2% had the MYD88L265P mutation. MRR and ORR were 88.9% and 96.3%, respectively (Cohort A: MRR, 88.9%; ORR, 94.4%; Cohort B: MRR, 88.9%; ORR, 100%). Median TTMR was 1.87 mo. PFS and OS were not reached with a median follow‐up of 6.5 and 8.3 mo for Cohorts A and B, respectively. The most common adverse events (AEs) were rash (44.4%), neutropenia (25.9%), and leukopenia (22.2%), with most AEs classified as grade 1 or 2. Grade ≥ 3 AEs included neutropenia (11.1%), lymphopenia (11.1%), and leukopenia (7.4%). No grade 5 AEs were noted. All bleeding events were grade 1; none were associated with drug‐related atrial fibrillation or hypertension. Although the follow‐up duration was relatively short, the study met the primary endpoint. Therefore, tirabrutinib monotherapy is considered to be highly effective for both untreated and relapsed/refractory WM with a manageable safety profile. (JapicCTI‐173646).  相似文献   
4.
An aggressive pancreatectomy was performed on a 53 year old Japanese man with advanced cancer of the pancreas. The tumor originated from the body of the pancreas and invaded the stomach, duodenum, left kidney, transverse colon and common hepatic artery. An unexpected cancer was also found in the head of the pancreas during the operation. Therefore, total pancreatectomy, total gastrectomy, left adrenonephrectomy, resection of the left transverse colon and dissection of the regional lymph nodes were performed. Resection of the common hepatic artery was also performed, followed by an end-to-end anastomosis between the common hepatic artery and celiac trunk. The postoperative course was uneventful and the patient was doing well until nine months after the operation when multiple metastatic lesions were noted in the liver. He died 391 days after the operation from hepatic failure.  相似文献   
5.
The ability of various synthetic muramyl dipeptide (MDP) derivatives to induce the production of interleukin-1 (IL-1) and colony stimulating factor (CSF) in vitro and in vivo and to induce cytotoxic macrophages was studied. 6-O-L18-MDP(Me) and MDP-Lys(L18), which were potent inducers of IL-1 and CSF production and of cytotoxic macrophages, had protective activity against Sendai virus infection in mice. In contrast, 1-O-L18-(6-O-P)-MDP(Me) and 2-N-L18-MDP exhibited weak or no ability to induce IL-1 and CSF production and no induction of tumoricidal macrophages, and did not protect against infection of Sendai virus. MDP derivatives, except 2-N-L18-MDP, efficiently rendered macrophages cytotoxic against target cells in the presence of murine recombinant interferon-gamma in vitro. The derivatives that induced cytokines and cytotoxic macrophages appeared to produce anti-viral activity.  相似文献   
6.
The excitatory responses of deflationary slowly adapting pulmonary stretch receptor (SAR) activity to lung deflation ranging from approximately -15 to -25 cm of H(2)O for approximately 5 s were examined before and after administration of flecainide, a Na(+) channel blocker, and K(+) channel blockers, such as 4-aminopyridine (4-AP) and tetraethylammonium (TEA). The experiments were performed in anesthetized, artificially ventilated rats after unilateral vagotomy. The deflationary SARs increased their activity during lung deflation and its effect became more pronounced by increasing the degree of negative pressure. During lung deflation the average values for the deflationary SAR adaptation index (AI) were below 40%. Intravenous administration of veratridine (50 microg/kg), an Na(+) channel opener, stimulated deflationary SAR activity: one maintained excitatory activity mainly during deflation and the other receptors showed a tonic discharge during both deflation and inflation. Despite the difference in deflationary SAR firing patterns after veratridine administration, flecainide treatment (6.0 mg/kg) blocked veratridine-induced deflationary SAR stimulation and also caused strong inhibition of the excitatory responses of deflationary SARs to lung deflation. Under these conditions, the average values for deflationary SAR AI were over 90%. The responses of deflationary SARs and deflationary SAR AI to lung deflation were not significantly altered by pretreatment with either 4-AP (0.7 and 2.0 mg/kg) or TEA (2.0 and 6.0 mg/kg). These results suggest that the excitatory effect of lung deflation on deflationary SAR activity is mediated by the activation of flecainide-sensitive Na(+) channels on the nerve terminals of deflationary SARs.  相似文献   
7.
Two hybridomas secreting two monoclonal antibodies IgG1 B1.4 and IgG2a B1.6 were obtained by immunizing BALB/c mice with human bladder cancer cell line EJ-1. In immunohistochemical staining of cryopreserved tissues, B1.4 reacted with 0 of 9 grade 1 TCC, 6 of 11 grade 2, all of 6 grade 3 and five metastatic specimens. The antigen recognized by B1.4 was not expressed by normal urothelial cells but were expressed by vascular endothelial cells and muscle of tunica media. The target antigen of B1.6 was expressed by normal urothelial cells and all grade of TCC. In this study, it was demonstrated that poorly differentiated bladder cancer and metastatic specimens of bladder cancer express a vascular carbohydrate antigen. Taking the escape mechanism of immune surveillance, into consideration, it is possible that the antigen recognized by B1.4 is an indicator of metastatic potential of bladder cancer.  相似文献   
8.
MR appearance of parasymphyseal insufficiency fractures of the os pubis   总被引:1,自引:0,他引:1  
Objective. To clarify the MRI features of parasymphyseal insufficiency fractures of the os pubis. Design and patients. MRI was performed in four postmenopausal women with parasymphyseal insufficiency fractures. The diagnosis was confirmed with plain films in every patient. T1-weighted and T2-weighted images were obtained in four patients using a 1.5-T unit. Postcontrast T1-weighted imaging was also done in three patients. Results and conclusions. MRI of pubic parasymphyseal insufficiency fracture characteristically demonstrates a hyperintense mass lesion with a hypointense rim on T2-weighted imaging, showing peripheral and septal enhancement after contrast administration. It is important to have this entity in mind in patients with osteoporosis, especially in patients with a history of pelvic irradiation for malignant disease, so as not to misinterpret it as a chondroid tumor or bone metastasis.  相似文献   
9.
Cerebral ischemia induces the expression of several growth factors and cytokines, which protect neurons against ischemic insults. Recent studies showed that granulocyte colony-stimulating factor (G-CSF) has a neuroprotective effect through the signaling pathway for the antiapoptotic cascade. The current study was designed to assess the neuroprotective mechanisms of G-CSF in ischemia/reperfusion injury using bone marrow chimera mice known to express enhanced green fluorescent protein (EGFP). Mice were subjected to ischemia/reperfusion and divided into two groups: those treated with G-CSF (G-CSF group) and vehicle (control group) (n = 35 in each group). Immunohistochemistry and immunoblotting for antiapoptotic protein, nitrotyrosine, and inducible nitrate oxide synthase (iNOS) were performed. G-CSF significantly reduced stroke volume (34%, P < 0.006). G-CSF upregulated Stat3, pStat3, and Bcl-2 (P < 0.05), and suppressed iNOS and nitrotyrosine expression. In EGFP chimera mice, G-CSF decreased the migration of Iba-1/EGFP-positive bone marrow-derived monocytes/macrophages and increased intrinsic microglia/macrophages at ischemic penumbra (P < 0.05), suggesting that bone marrow-derived monocytes/macrophages are not involved in G-CSF-induced reduction of ischemic injury size. Our study indicated that G-CSF exerts a neuroprotective effect through the direct activation of antiapoptotic pathway, and suggested that G-CSF is important for expansion of the therapeutic time window in patients with cerebral ischemia.  相似文献   
10.
We have examined the influence of fibroblasts on the invasive and migratory potential of highly metastatic melanoma B16-BL6 and weakly metastatic B16-FI cells in vitro. Co-culture of B16-BL6 cells with a fibroblast monolayer without cellular contact in a Transwell chamber more effectively induced tumor-cell invasion into Matrigel basement membrane than co-culture of B16-FI cells with a fibroblast monolayer. The activity was closely correlated with the chemotactic migration of tumor cells toward the fibroblast monolayer. We also found that the conditioned medium (CM) from the co-culture of fibroblasts with B16-BL6 cells without cellular contact, i.e., CM (B16-BL6/fibroblast), rather than from co-culture with B16-FI cells, could potentially promote the migration of tumor cells of both types. Tumor cells did not chemotactically migrate to the CM (B16-BL6), CM (B16-FI) or CM (fibroblast). Antibodies against TGF-β1 or FN almost completely abolished the chemotactic migration of B16-BL6 cells to the CM (B16-BL6/fibroblast) or CM (TGF-β1 -treated fibroblast) when these antibodies were c-incubated with fibroblasts and either B16-BL6 or TGF-β1. In contrast, the anti-EGF antibody did not show any inhibitory effects. Analysis of amounts of TGF-β1 or FN in various CM using ELISA plates, and using their specific antibodies, revealed that the concentration of TGF-β1 in the CM (B16-BL6) was slightly higher than in the CM (B16-FI), and the amount of FN in the CM (B16-BL6/fibroblast) was twice as high as in the CM (B16-FI /fibroblast). These results suggest that TGF-β1 released from B16-BL6 cells can stimulate fibroblasts to produce FN; consequently, the tumor cells were able to chemotactically migrate toward the released FN, and the differences in invasive and migratory activities towards fibroblasts in B16-BL6 and B16-FI cells may in part be due to the amounts of TGF-β1 from tumor cells and of FN from TGF-β1 -stimulated fibroblasts.  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