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   252971篇
  免费   21608篇
  国内免费   15162篇
耳鼻咽喉   2207篇
儿科学   3159篇
妇产科学   4994篇
基础医学   29395篇
口腔科学   4400篇
临床医学   32404篇
内科学   41193篇
皮肤病学   2905篇
神经病学   13986篇
特种医学   8979篇
外国民族医学   102篇
外科学   27528篇
综合类   36379篇
现状与发展   52篇
一般理论   45篇
预防医学   16012篇
眼科学   6847篇
药学   25459篇
  187篇
中国医学   11963篇
肿瘤学   21545篇
  2024年   780篇
  2023年   3754篇
  2022年   9197篇
  2021年   12125篇
  2020年   8975篇
  2019年   7982篇
  2018年   8387篇
  2017年   7364篇
  2016年   7032篇
  2015年   10627篇
  2014年   13395篇
  2013年   12456篇
  2012年   18393篇
  2011年   20180篇
  2010年   12413篇
  2009年   9967篇
  2008年   13337篇
  2007年   13364篇
  2006年   12909篇
  2005年   12923篇
  2004年   8893篇
  2003年   7909篇
  2002年   6800篇
  2001年   6182篇
  2000年   6298篇
  1999年   6569篇
  1998年   3767篇
  1997年   3768篇
  1996年   2888篇
  1995年   2671篇
  1994年   2292篇
  1993年   1536篇
  1992年   2335篇
  1991年   2045篇
  1990年   1704篇
  1989年   1488篇
  1988年   1284篇
  1987年   1197篇
  1986年   959篇
  1985年   760篇
  1984年   498篇
  1983年   387篇
  1982年   228篇
  1981年   202篇
  1980年   195篇
  1979年   244篇
  1978年   145篇
  1977年   116篇
  1976年   97篇
  1974年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
目的探讨去势大鼠股骨近段植入牛骨形成蛋白(bone morphorgeneic protein,BMP)后其骨生物力学强度及髓腔面积的变化。方法随机选取6月龄wistar雌性大鼠22只,摘除卵巢制作绝经后骨质疏松模型成功后,同一只动物双侧肢体对照,试验侧股骨颈植入牛骨形成蛋白及纤维蛋白(FS)复合物,对照侧植入纤维蛋白,术后4周、8周处死取材,测量股骨近端生物力学强度及髓腔面积和截面面积。结果4周后,试验侧与对照侧股骨近端骨生物力学强度和髓腔面积无明显差异;8周后,试验侧股骨近端生物力学强度较对照侧增高;髓腔面积较对照侧有较明显的减小(P<0.05)。结论股骨近端局部植入BMP可提高去势大鼠股骨近端局部的生物力学强度和减小近端髓腔面积和截面积,其可能减少骨质疏松性髋部骨折置换后假体的松动,成为骨质疏松性骨折假体置换中新的辅助治疗方法。  相似文献   
992.
BackgroundHepatocellular carcinoma (HCC) is the fifth most common cancer in the world, and more than half of the newly diagnosed cases are chronic hepatitis B patients. Due to the lack of specific clinical manifestations, many patients are already at an advanced stage at the time of diagnosis and therefore have missed the best time for treatment. Organs in a pathological state usually secrete specific substances into the blood, which can indirectly indicate the pathological state of the organ, so some biological markers in the blood can be used as a tool to predict the incidence of HCC.MethodsThe Research articles related to HCC were collected by searching PubMed databases with the keywords “hepatocellular carcinoma”, “serum biomarker”, “hepatitis B”, “prediction” and “prognosis”, and Additional articles were identified by manual search of references found in the primary articles, followed by a summary and review.ResultsViral hepatitis is the main cause of HCC worldwide, and this phenomenon is particularly prominent in Asian and African populations. A variety of serological markers including M2BPGi, IL-6 and COMP can be used to predict the incidence of long-term HCC in patients. The risk of HCC is dynamic rather than constant, and dynamic detection will help improve prediction accuracy. For hepatitis B patients, HBV DNA load and HBcr Ag are important predictive markers of HCC.ConclusionFor a high-risk population of HCC, early risk prediction is helpful to guide clinical work, and timely adjustments of the screening frequency and treatment plan are helpful to prolong the survival time of HCC patients.  相似文献   
993.
护理干预对冠心病患者生活质量的影响   总被引:1,自引:0,他引:1  
目的观察护理干预对冠心病患者生活质量的影响。方法将100例老年冠心病患者随机分为干预组和对照组,每组各50例。两组均实施常规护理,干预组在此基础上给予健康教育、康复训练、心理护理等护理干预,并于护理干预8w末采用西雅图心绞痛调查量表进行评估分析。结果护理干预8w末,干预组西雅图心绞痛调查量表躯体活动受限程度评分显著高于对照组(P〈0.05);治疗满意程度、疾病认识程度和总分评分显著高于对照组(P〈0.01)。结论对冠心病患者实施完善的护理干预体系可提高患者的生活质量。  相似文献   
994.
BackgroundThere is increasing attention on the association of socioeconomic status and individual behaviors (SES/IB) with mental health. However, the impacts of SES/IB on mental disorders are still unclear. To provide evidence for establishing feasible strategies on disease screening and prevention, we implemented Mendelian randomization (MR) design to appraise causality between SES/IB and mental disorders.MethodsWe conducted a two-sample MR study to assess the causal effects of SES and IB (dietary habits, habitual physical activity, smoking behaviors, drinking behaviors, sleeping behaviors, leisure sedentary behaviors, risky behaviors, and reproductive behaviors) on three mental disorders, including bipolar disorder, major depressive disorder and schizophrenia. A series of filtering steps were taken to select eligible genetic instruments robustly associated with each of the traits. Inverse variance weighted was used for primary analysis, with alternative MR methods including MR-Egger, weighted median, and weighted mode estimate. Complementary methods were further used to detect pleiotropic bias.ResultsAfter Bonferroni correction and rigorous quality control, we identified that SES (educational attainment), smoking behaviors (smoking initiation, number of cigarettes per day), risky behaviors (adventurousness, number of sexual partners, automobile speeding propensity) and reproductive behavior (age at first birth) were causally associated with at least one of the mental disorders.ConclusionsMR study provides robust evidence that SES/IB play broad impacts on mental disorders.  相似文献   
995.
ObjectiveTo evaluate the effect of different levels of physician experience on the high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and to provide a reference for the use of non-perfused volume ratio (NPVR) standards during training.MethodsThis prospective multicentre study enrolled patients with uterine fibroids. The effect of the physician’s level of experience on the outcomes under different NPVR standards and the learning curve of six centres without HIFU experience were analysed. The impact of patient demographic and clinical characteristics were also evaluated.ResultsA total of 1352 patients from 20 centres were included in the study. The median NPVRs were 92.00%, 88.10% and 92.86% in the no experience group, inexperienced group and experienced group, respectively. Posterior wall fibroids, lateral wall fibroids and fundus fibroids were inversely correlated with NPVR, while experienced physicians were positively correlated with NPVR. With NPVR ≥ 70% and NPVR ≥ 80% standards, physicians in the no experience group completed the learning curve on the 11th and 16th procedure, respectively. Physicians under a standard of an NPVR ≥ 90% did not complete the learning curve.ConclusionsNPVR ≥ 80% is a standard that is worth using for HIFU treatment of uterine fibroids.  相似文献   
996.
997.
The protective human antibody response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) focuses on the spike (S) protein, which decorates the virion surface and mediates cell binding and entry. Most SARS-CoV-2 protective antibodies target the receptor-binding domain or a single dominant epitope (“supersite”) on the N-terminal domain (NTD). Using the single B cell technology called linking B cell receptor to antigen specificity through sequencing (LIBRA-Seq), we isolated a large panel of NTD-reactive and SARS-CoV-2–neutralizing antibodies from an individual who had recovered from COVID-19. We found that neutralizing antibodies against the NTD supersite were commonly encoded by the IGHV1-24 gene, forming a genetic cluster representing a public B cell clonotype. However, we also discovered a rare human antibody, COV2-3434, that recognizes a site of vulnerability on the SARS-CoV-2 S protein in the trimer interface (TI) and possesses a distinct class of functional activity. COV2-3434 disrupted the integrity of S protein trimers, inhibited the cell-to-cell spread of the virus in culture, and conferred protection in human angiotensin-converting enzyme 2–transgenic (ACE2-transgenic) mice against the SARS-CoV-2 challenge. This study provides insight into antibody targeting of the S protein TI region, suggesting this region may be a site of virus vulnerability.  相似文献   
998.
Nephropathy caused by diabetes mellitus (DM) is the main cause of end-stage renal disease (ESRD). To understand the association of dietary intake with renal function indicators among patients with diabetic nephropathy (DN), this cross-sectional study was conducted at the dietetic consultation clinic of the Taoyuan Armed Forces General Hospital in Taiwan. In total, 317 participants were recruited for this study. Patients with diabetes who had a urinary albumin–creatinine ratio (UACR) of ≥30 mg/g were defined as having DN. The anthropometric characteristics, blood biochemistry, and renal function of the participants were assessed. Furthermore, a semiquantitative food frequency questionnaire (SQFFQ) was administered to investigate the dietary intake of the participants in the DM and DN groups. The result showed that participants in the DN group were older, had longer diabetes duration and poorer glycemic control and renal function than those in the DM group. Logistic regression models revealed that intake of high-fat marine fishes had the lowest odds ratio (OR) for DN risk compared with other fishes (OR: 0.868; 95% CI: 0.781–0.965, p = 0.009). Shellfish, soybean products, and skim milk also provided better protective effects to decrease the risk of DN. A further analysis of polyunsaturated fatty acids revealed that Σn-3 PUFAs significantly reduced DN risk, while Σn-6 PUFAs did not, especially EPA (OR: 0.821; 95% CI: 0.688–0.979, p = 0.029) and DHA (OR: 0.903; 95% CI: 0.823–0.992, p = 0.033) regardless of whether the variables were adjusted, including diabetes duration, age, and HbA1c. Our findings suggest that a diet that incorporates high-fat fish, shellfish, soybean products, and a lower Σn-6/Σn-3 ratio can mitigate DN risk.  相似文献   
999.
Air pollutants of PM2.5 can alter the composition of gut microbiota and lead to inflammation in the lung and gastrointestinal tract. The aim of this study was to evaluate the protective effect of a novel herbal extract blend, FC, composed of Lonicera japonica extract, Momordica grosvenori extract, and broccoli seed extract, on PM2.5-induced inflammation in the respiratory and intestinal tract. A549 cells and THP-1 cells, as well as C57BL/6 mice, were stimulated with PM2.5 to establish in vitro and in vivo exposure models. The models were treated with or without FC. The expression of inflammatory cytokines and tight junction proteins were studied. Proteomic analysis was performed to elucidate mechanisms. Mouse feces were collected for gut microbiota analysis. FC was shown to modulate the upregulation of pro-inflammatory cytokines mRNA expression in A549 and THP-1 cells and downregulated tight junction proteins mRNA expression in A549 cells due to PM2.5 stimulation. In animal models, the decreased expression of the anti-inflammatory factor il-10, tight junction protein ZO-1, and the elevated expression of COX-2 induced by PM2.5 were improved by FC intervention, which may be associated with zo-1 and cox-2 signaling pathways. In addition, FC was shown to improve the gut microbiota by increasing the abundance of beneficial bacteria.  相似文献   
1000.
Adenoviruses can cause infections in people of all ages at all seasons of the year. Adenovirus infections cause mild to severe illnesses. Children, immunocompromised patients, or those with existing respiratory or cardiac disease are at higher risk. Unfortunately, there are no commercial drugs or vaccines available on the market for adenovirus infections. Therefore, there is an urgent need to discover new antiviral drugs or drug targets for adenovirus infections. To identify potential antiviral agents for adenovirus infections, we screened a drug library containing 2138 compounds, most of which are drugs with known targets and past phase I clinical trials. On a cell-based assay, we identified 131 hits that inhibit adenoviruses type 3 and 5. A secondary screen confirmed the antiviral effects of 59 inhibitors that inhibit the replication of adenoviruses type 3 or 5. Most of the inhibitors target heat shock protein, protein tyrosine kinase, the mTOR signaling pathway, and other host factors, suggesting that these host factors may be essential for replicating adenoviruses. Through this study, the newly identified adenovirus inhibitors may provide a start point for developing new antiviral drugs to treat adenovirus infections. Further validation of the identified drug targets can help the development of new therapeutics against adenovirus infections.  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