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   63699篇
  免费   4505篇
  国内免费   148篇
耳鼻咽喉   825篇
儿科学   1741篇
妇产科学   1595篇
基础医学   10465篇
口腔科学   1681篇
临床医学   6005篇
内科学   12788篇
皮肤病学   963篇
神经病学   5959篇
特种医学   2677篇
外国民族医学   45篇
外科学   8206篇
综合类   541篇
一般理论   83篇
预防医学   4954篇
眼科学   1204篇
药学   4594篇
中国医学   162篇
肿瘤学   3864篇
  2022年   468篇
  2021年   1029篇
  2020年   649篇
  2019年   918篇
  2018年   1122篇
  2017年   781篇
  2016年   915篇
  2015年   1086篇
  2014年   1346篇
  2013年   2323篇
  2012年   2990篇
  2011年   3085篇
  2010年   2230篇
  2009年   1867篇
  2008年   2789篇
  2007年   2932篇
  2006年   2916篇
  2005年   2760篇
  2004年   2821篇
  2003年   2567篇
  2002年   2638篇
  2001年   2155篇
  2000年   2208篇
  1999年   1986篇
  1998年   881篇
  1997年   736篇
  1996年   643篇
  1995年   675篇
  1994年   560篇
  1993年   612篇
  1992年   1448篇
  1991年   1395篇
  1990年   1336篇
  1989年   1322篇
  1988年   1101篇
  1987年   1105篇
  1986年   1048篇
  1985年   960篇
  1984年   695篇
  1983年   650篇
  1982年   461篇
  1981年   443篇
  1980年   382篇
  1979年   626篇
  1978年   377篇
  1977年   357篇
  1975年   375篇
  1974年   414篇
  1973年   347篇
  1972年   340篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Osteoscleroses are a heterogeneous group of bone remodeling disorders characterized by an increase in bone density. Here we report on a consanguineous Lebanese family in which two sisters, aged 39 and 36 years, exhibit a severe genu varum, a square‐face appearance, high forehead, slight proptosis of the eyes, symmetric enlargement of the jaw, protruding chin, and short stature. Bone X‐rays showed the presence of hyperostosis of the cranial base and vault with increased density of the orbits, hyperostosis of the bones, thickening of the cortices, diaphyseal modeling defects, cortical thickening of the medullary cavity, mild enlargement of the medullary cavity of the short long bones, short femoral necks, increased width of the ribs, and narrow interpedicular distances of the lower lumbar spine. Osteodensitometry showed values 200% to 300% above values for age. A cervical MRI revealed the presence of a diffuse osteosclerosis with calcification of the posterior vertebral ligament and a narrow canal between C2 and T2. Blood test results were unremarkable. Serum osteocalcin levels were in the normal range, whereas high values of serum C ‐ telopeptide were noted. A bone biopsy showed only the presence of compact bone and did not allow for histomorphometric analysis. Molecular studies excluded genes known to be involved in sclerosing bone dysplasias as the cause of this condition. In vitro analysis of osteoclast function indicated that contrary to most cases of autosomal recessive osteopetrosis, osteoclasts both formed and resorbed but exhibited a small decrease in resorptive activity compared with osteoclasts generated from normal control individuals. Differential diagnoses are discussed, and the possibility that this may be a novel clinical entity is raised. © 2010 American Society for Bone and Mineral Research.  相似文献   
992.
BackgroundMigraine is responsible for significant disability and societal burden. Recently, drugs targeting the calcitonin gene-related peptide (CGRP) pathway raised new hopes. CGRP, a potent vasodilator, plays a key role in the pathogenesis of migraine attacks. The deficiency of CGRP is involved in Raynaud’s phenomenon, which consists of abnormal vasoconstriction of the digits. We aimed to assess the potential association of Raynaud’s phenomenon with CGRP-targeting drugs, analyzing real-world data from the World Health Organization (VigiBase®).MethodsWe queried all reports of Raynaud’s phenomenon involving a CGRP-targeting drug. We sought disproportionate reporting of Raynaud’s phenomenon with these drugs. For this purpose, we relied on the calculation of the Information Component (IC). A positive lower end of the 95% confidence interval (CI) of the IC defines a statistically significant association. As migraine patients are prone to Raynaud’s phenomenon, we also calculated the IC of Raynaud’s phenomenon with CGRP-targeting drugs compared to 5HT1B/D agonists (triptans), and beta-blockers used in the treatment of migraine.ResultsOverall, 99 reports of Raynaud’s phenomenon involving CGRP-targeting drugs have been yielded in VigiBase®. The most reported CGRP-targeting drug was erenumab, with 56 reports (56.6%). The median time to onset was 84 days. No fatality was notified, but one patient suffered from gangrene and extremity necrosis. As a whole, CGRP-targeting drugs were significantly associated with Raynaud’s phenomenon, with an IC of 3.3 (95%CI: 3.0–3.5). There was a disproportionate reporting of Raynaud’s phenomenon with CGRP-targeting drugs compared to triptans (IC 0.4; 95%CI: 0.1–0.6) and to beta-blockers (IC 0.5; 95%CI: 0.2–0.7) as well.ConclusionsThere is a significant disproportionality signal of Raynaud’s phenomenon with CGRP-targeting. This signal stands out when CGRP-targeting drugs are compared to other drugs used in patients with migraine. This study is limited by missing data in pharmacovigilance reports. CGRP-targeting drugs may be subject to Weber effect and reporting bias. Nonetheless, CGRP blockade might be the last straw that disrupts the physiological balance of vascular response in patients at-risk of Raynaud’s phenomenon. Pending further data regarding vascular safety of CGRP-targeting drugs, caution is warranted in these patients.  相似文献   
993.
BackgroundBRAFV600E mutations occur in fewer than 10% of all patients with metastatic colorectal cancer (CRC) and arise from sessile serrated adenomas. Despite efficacy with targeted therapies against MAPK signaling and with immunotherapies in this population, survival outcomes for patients with BRAFV600E mutated metastatic CRC in general are poor. Characteristics distinguishing patients with BRAFV600E mutated metastatic CRC with favorable versus unfavorable outcomes have not been well annotated.MethodsRecords of 187 patients with BRAFV600E mutated metastatic CRC evaluated at MD Anderson Cancer Center between 2005–2020 were reviewed. Patients with the shortest and longest metastatic survival (N=25 for each group) were compared. Associations between prognostic group and clinical/pathologic features were measured by odds ratio and for median survival by log-rank testing.ResultsMedian metastatic survival differed between the 2 BRAFV600E mutated metastatic CRC populations (8.6 vs. 83.9 months, hazard ratio 32; P<0.0001). Patients with poor survival more commonly had hepatic involvement [75% vs. 28%, odds ratio (OR) 8.1, 95% confidence interval (CI): 2.3–29; P=0.001]. Patients with favorable survival were more likely to develop metachronous metastases (52% vs. 16%, OR 5.7, 95% CI: 1.5–21; P=0.01) and undergo definitive locoregional therapy to metastatic disease (40% vs. 0%, OR 34.5, 95% CI: 1.9–630; P=0.01). Microsatellite instability (36% vs. 4%, OR 19.8, 95% CI: 2.2–180; P=0.008) and prior tobacco exposure (44% vs. 16%, OR 4.1, 95% CI: 1.1–15.6, P=0.04) were associated with a favorable prognosis. Durable responses to MAPK-targeted therapies and immunotherapy were noted in the favorable group.ConclusionsA small fraction of patients with BRAFV600E mutated metastatic CRC can achieve excellent long-term survival which belies conventional context and is driven by either surgical metastectomy or by systemic treatment options. While poor overall prognosis remains the recognized outcome for most patients with BRAFV600E mutated metastatic CRC, it is possible that few may achieve exceptionally favorable survival.  相似文献   
994.
995.
Ectopic Mer expression promotes pro-survival signaling and contributes to leukemogenesis and chemoresistance in childhood acute lymphoblastic leukemia (ALL). Consequently, Mer kinase inhibitors may promote leukemic cell death and further act as chemosensitizers increasing efficacy and reducing toxicities of current ALL regimens. We have applied a structure-based design approach to discover novel small molecule Mer kinase inhibitors. Several pyrazolopyrimidine derivatives effectively inhibit Mer kinase activity at sub-nanomolar concentrations. Furthermore, the lead compound shows a promising selectivity profile against a panel of 72 kinases and has excellent pharmacokinetic properties. We also describe the crystal structure of the complex between the lead compound and Mer, opening new opportunities for further optimization and new template design.  相似文献   
996.
997.
[目的]观察降脂颗粒治疗高脂血症(HLP)的临床疗效.[方法]对确诊为HLP的56例患者,分为治疗和对照组,治疗组给予降脂颗粒治疗,对照组给予绞股蓝总苷片,疗程为4周,疗程结束后进行疗效评定.[结果]治疗组中医证候改善总有效率为89%,与对照组比较具有统计学意义(P<0.05).总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)治疗前后两组比较有显著性差异(P<0.05).[结论]降脂颗粒治疗HLP疗效显著,并且能够改善一般症状.  相似文献   
998.
Insulin-like growth factor 1 (IGF-1) plays a pleiotropic role in multiple myeloma (MM), that is, in survival, proliferation, chemotaxis, and angiogenesis. Strategies targeting the IGF-1 receptor (IGF-1R) may therefore be important to develop efficient anti-MM agents. In this work we investigated the effect of an IGF-1R tyrosine kinase (IGF-1RTK) inhibitor (picropodophyllin or PPP) in the 5T33MM mouse model. In vitro data showed that PPP reduced IGF-1R autophosphorylation and downstream ERK activation, leading to inhibition of IGF-1-stimulated proliferation and vascular endothelial growth factor (VEGF) secretion of MM cells. In an in vivo study, PPP reduced the bone marrow tumor burden and serum paraprotein in 5T33MM mice by 77% and 90%, respectively, compared to vehicle-treated animals. Angiogenesis was assessed by quantifying the microvessel density on CD31-stained paraffin sections and this was reduced by 60% in the PPP-treated group. In a separate survival experiment, Kaplan-Meier analysis demonstrated a significant increase in survival in PPP-treated 5T33MM animals compared to the vehicle controls (28 versus 18 days). These data suggest that the IGF-1RTK inhibitor PPP possesses a marked antitumor activity and strongly points to the possibility of using IGF-1R inhibitors in the treatment of MM.  相似文献   
999.
1000.
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