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   1303195篇
  免费   97240篇
  国内免费   3893篇
耳鼻咽喉   18451篇
儿科学   42602篇
妇产科学   38011篇
基础医学   189669篇
口腔科学   36092篇
临床医学   111582篇
内科学   254930篇
皮肤病学   26755篇
神经病学   100379篇
特种医学   51044篇
外国民族医学   376篇
外科学   200241篇
综合类   32743篇
现状与发展   8篇
一般理论   301篇
预防医学   95424篇
眼科学   29657篇
药学   100787篇
  44篇
中国医学   4462篇
肿瘤学   70770篇
  2018年   12671篇
  2016年   10820篇
  2015年   12882篇
  2014年   17643篇
  2013年   25986篇
  2012年   36230篇
  2011年   38719篇
  2010年   23376篇
  2009年   21710篇
  2008年   36938篇
  2007年   39666篇
  2006年   40052篇
  2005年   39201篇
  2004年   37396篇
  2003年   36243篇
  2002年   35613篇
  2001年   58627篇
  2000年   59983篇
  1999年   50995篇
  1998年   14414篇
  1997年   12958篇
  1996年   13211篇
  1995年   12477篇
  1994年   11883篇
  1993年   10935篇
  1992年   41054篇
  1991年   40424篇
  1990年   39934篇
  1989年   38735篇
  1988年   36132篇
  1987年   35370篇
  1986年   33736篇
  1985年   32146篇
  1984年   23925篇
  1983年   20821篇
  1982年   12380篇
  1981年   10927篇
  1979年   22637篇
  1978年   15877篇
  1977年   13729篇
  1976年   12970篇
  1975年   14203篇
  1974年   16682篇
  1973年   16079篇
  1972年   15318篇
  1971年   14229篇
  1970年   13215篇
  1969年   12732篇
  1968年   11978篇
  1967年   10479篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
This meta-analysis focuses on the accuracy of upgrading to clinically significant prostate cancer (PCa) by multiparametric magnetic resonance imaging-targeted biopsy (MRI-TB) versus systematic biopsy (SB). We searched the Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, and Literatura Latino Americana em Ciências da Saúde databases through January 2020 for comparative, retrospective/prospective, paired-cohort, and randomized clinical trials with paired comparisons. The population consisted of patients with low-risk PCa in active surveillance with at least 1 index lesion on imaging. We evaluated the quality of evidence by using the Quality Assessment of Diagnostic Accuracy Studies-2 score. Group comparisons considered the differences between the area under the curve summary receiver operating characteristic curve in a 2-tailed method. We also compared the positive predictive value of the best single method (MRI-TB or SB) and the referral study test (combined biopsy, a combination of MRI-TB and SB). The meta-analysis included 6 studies enrolling 741 patients. The pooled sensitivity for the 2 groups was 0.79 (95% confidence interval, 0.74-0.83; I2 = 75%) and 0.67 (95% confidence interval, 0.63-0.74; I2 = 55.4%), respectively. The area under the curve for the MRI-TB and SB groups were 0.99 and 0.92 (P < .001), respectively. The positive predictive value for the MRI-TB and combined biopsy groups were similar. The accumulated evidence suggests better results for MRI-TB compared with SB. Therefore, use of MRI-TB alone may be preferable in patients in active surveillance harboring low-risk PCa.  相似文献   
93.
S. G. Brearley  S. Varey  A. Krige 《Anaesthesia》2023,78(10):1249-1255
Adequate postoperative analgesia is a key element of enhanced recovery programmes. Thoracic epidural analgesia is associated with superior postoperative analgesia but can lead to complications. Rectus sheath catheter analgesia may provide an alternative. In a nested qualitative study (within a two-year randomised controlled trial) focussing on the acceptability, expectations and experiences of receiving the interventions, participants (n = 20) were interviewed 4 weeks post-intervention using a grounded theory approach. Constant comparative analysis, with patient and public involvement, enabled emerging findings to be pursued through subsequent data collection. We found no notable differences regarding postoperative acceptability or the experience of pain management. Pre-operatively, however, thoracic epidural analgesia was a source of anticipatory fear and anxiety. Both interventions resulted in some experienced adverse events (proportionately more with thoracic epidural analgesia). Participants had negative experiences of the insertion of thoracic epidural analgesia; others receiving the rectus sheath catheter lacked confidence in staff members' ability to manage the local anaesthetic infusion pump. The anticipation of the technique of thoracic epidural analgesia, and concerns about its impact on mobility, represented an additional, unpleasant experience for patients already managing an illness experience, anticipating a life-changing operation and dealing with concerns about the future. The anticipation of rectus sheath catheter analgesia was not associated with such anxieties. Patients' experiences start far earlier than the experience of the intervention itself through anticipatory anxieties and fears about receiving a technique and its potential implications. Complex pain packages can take on greater meaning than their actual efficacy in relieving postoperative pain. Future research into patient acceptability and experience should not focus solely on efficacy of pain relief but should include anticipatory fears, anxieties and experiences.  相似文献   
94.
目的 探讨人格特征对喉鳞状细胞癌(LSCC)患者术后近期心理健康状况的影响。方法 纳入2017年1月—2019年12月在湖北省肿瘤医院行手术治疗的119例男性LSCC患者,术后5~7 d采用SCL-90、SAS、SDS自评量表评估术后心理状态,采用EPQ问卷测评患者的人格特征。多元线性逐步回归方法分析LSCC患者术后近期SAS和SDS评分的影响因素。结果 男性LSCC患者术后SCL-90、SAS、SDS得分显著高于中国常模(P≤0.05),EPQ中精神质(P)量表和神经质(N)量表得分高于中国常模(P<0.01)。男性LSCC患者术后躯体化、强迫、焦虑、抑郁、敌对、恐怖、偏执、精神病性因子得分均显著高于中国常模(P<0.05)。家庭收入、手术方式、术后近期是否行放化疗、P和N人格特征是术后SAS评分的影响因素(均P<0.01);家庭收入、手术方式、术后近期是否行放化疗和N人格特征是术后SDS评分的影响因素(P<0.01)。结论 LSCC患者术后近期存在抑郁、焦虑等心理障碍;具有P和N人格特征;家庭收入、手术方式、术后近期是否行放化疗以及P和N人格特征是影响术后SAS及SDS评分的独立危险因素。  相似文献   
95.
96.
ObjectiveIdentify factors associated with healthcare providers' frequency of depot medroxyprogesterone acetate (DMPA) provision to adolescents.Study designWe analyzed data from surveys mailed to a nationally representative sample of public-sector providers and office-based physicians (n=1984). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with frequent DMPA provision to adolescents in the past year.ResultsAlthough most providers (>95%) considered DMPA safe for adolescents, fewer reported frequent provision (89% of public-sector providers; 64% of office-based physicians). Among public-sector providers, factors associated with lower odds of frequent provision included working in settings without Title X funding (aOR 0.44, 95% CI 0.30–0.64), reporting primary care as their primary clinical focus versus reproductive or adolescent health (aOR 0.42, 95% CI 0.28–0.61), and providing fewer patients with family planning services. Among office-based physicians, factors associated with lower odds of frequent provision included specializing in obstetrics/gynecology (aOR 0.50, 95% CI 0.27–0.91) and family medicine (aOR 0.21, 95% CI 0.09–0.47) versus adolescent medicine, completing training ≥15 versus <5 years ago (aOR 0.27, 95% CI 0.09–0.83), and reporting that 0–24% of patients pay with Medicaid or other government healthcare assistance versus ≥50% (aOR 0.23, 95% CI 0.09–0.61). The reason most commonly reported by providers for infrequent DMPA provision was patient preference for another method.ConclusionsWhile most providers reported frequently providing DMPA to adolescents, training on evidence-based recommendations for contraception, focused on subgroups of providers with lower odds of frequent DMPA provision, may increase adolescents' access to contraception.ImplicationsAlthough >95% of providers considered depot medroxyprogesterone (DMPA) a safe contraceptive for adolescents, only 89% of public-sector providers and 64% of office-based physicians reported frequently providing DMPA to adolescents. Provider training on evidence-based recommendations for contraception counseling and provision may increase adolescents' access to DMPA and all methods of contraception.  相似文献   
97.
98.
目的:探讨建立一种放射治疗全身器官剂量数据库平台的可行性。方法:使用基于深度学习的自动勾画软件DeepViewer?1例食管癌患者的全身CT上勾画全身器官,然后利用基于GPU加速的蒙特卡罗软件ARCHER计算相应的器官剂量分布,最后利用Lyman-Kutcher-Burman(LKB)模型评估放疗患者正常组织并发症概率(NTCP)。结果:针对该病例,成功建立基于DeepViewer?ARCHER和LKB模型的全身器官剂量数据库,发现距离靶区越近的器官剂量越大,其中心脏与靶区间距离最小,剂量为14.11 Gy,但因其模型参数特殊,通过LKB模型计算的NTCP为0.00%;左、右肺的剂量分别为3.19和1.16 Gy,但是NTCP值却很大,分别为2.13%和1.60%。对于距离靶区较远的头颈部器官(视交叉、视神经和眼)和腹部器官(直肠、膀胱和股骨头)剂量分别约为9和2 mGy,并且NTCP均近似为0.00%。结论:研究结果证明通过自动勾画软件DeepViewer?蒙特卡罗软件ARCHER和LKB模型建立全身器官剂量数据库的可行性。  相似文献   
99.
Background: Most theoretical models of self-determination suggest that both environmental and personal factors influence the development of self-determination. The design and implementation of interventions must be conducted with foreknowledge of such mediating and moderating factors if the intervention is to be successful.

Methods: The purpose of this study was to examine the degree to which several personal factors and school characteristics affect and explain students’ self-determination. A total of 232 students with intellectual disability from Spain participated. Their self-determination level was assessed by the ARC-INICO Scale.

Results: Students with moderate levels of intellectual disability obtained significantly lower scores on self-determination than their peers with mild intellectual disability. There were significant differences in relation to the level of support needs and their experience with transition programs. The level of support needs was a significant predictor.

Conclusion: These findings contribute to current research in this field and practical implications were discussed.  相似文献   

100.
International Journal of Clinical Pharmacy - Background Drug-related problems (DRP) following hospital discharge may cause morbidity, mortality and hospital re-admissions. It is unclear whether a...  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