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   54327篇
  免费   4832篇
  国内免费   3328篇
耳鼻咽喉   594篇
儿科学   794篇
妇产科学   465篇
基础医学   5071篇
口腔科学   869篇
临床医学   6189篇
内科学   7030篇
皮肤病学   590篇
神经病学   2650篇
特种医学   2306篇
外国民族医学   12篇
外科学   6474篇
综合类   11058篇
现状与发展   23篇
一般理论   4篇
预防医学   4753篇
眼科学   891篇
药学   5654篇
  65篇
中国医学   3699篇
肿瘤学   3296篇
  2024年   204篇
  2023年   721篇
  2022年   1815篇
  2021年   2531篇
  2020年   2026篇
  2019年   1532篇
  2018年   1590篇
  2017年   1599篇
  2016年   1474篇
  2015年   2486篇
  2014年   2968篇
  2013年   3435篇
  2012年   4949篇
  2011年   5153篇
  2010年   3944篇
  2009年   3264篇
  2008年   3742篇
  2007年   3341篇
  2006年   3088篇
  2005年   2522篇
  2004年   1928篇
  2003年   1764篇
  2002年   1367篇
  2001年   890篇
  2000年   704篇
  1999年   457篇
  1998年   261篇
  1997年   248篇
  1996年   230篇
  1995年   222篇
  1994年   161篇
  1993年   117篇
  1992年   127篇
  1991年   134篇
  1990年   119篇
  1989年   107篇
  1988年   88篇
  1987年   90篇
  1986年   80篇
  1985年   75篇
  1984年   85篇
  1983年   59篇
  1982年   56篇
  1981年   57篇
  1980年   56篇
  1979年   55篇
  1978年   50篇
  1975年   41篇
  1974年   44篇
  1973年   38篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
71.
目的 :探讨肾衰透析患者拔牙的安全性。 方法 :对 42例肾衰血透患者行 98次拔牙手术 ,共拔除患牙 12 2颗 ,术前采取全口洁治、服用抗生素、控制血压等措施 ,术后加强局部止血处理 ,预防出血、感染及心血管系统等并发症的发生。 结果 :透析组术后出血 44次 ,拔牙创口血块充盈不良或脱落 2 7次 ;对照组分别为 4和 5次 (94次手术 ,P<0 .0 5 )。拔牙创口定期观察 1个月 ,均愈合良好。 结论 :慢性肾衰患者通过透析 ,尿毒症得到控制和改善时 ,在作好围拔牙期处理的情况下 ,行拔牙手术是安全可行的  相似文献   
72.
Yu  Jinbo  Chen  Xiaohong  Wang  Yaqiong  Liu  Zhonghua  Shen  Bo  Teng  Jie  Zou  Jianzhou  Ding  Xiaoqiang 《International urology and nephrology》2021,53(4):785-795
International Urology and Nephrology - It is unclear which time-points of intradialytic blood pressure (BP) best predict prognosis. Thus, it is important to assess the association between different...  相似文献   
73.
Germplasm cryopreservation and expansion of gonocytes/prospermatogonia or spermatogonial stem cells (SSCs) are important; however, it's difficult in cattle. Since inhibitors of Mek1/2 and Gsk3β (2i) can enhance pluripotency maintenance, effects of 2i-based medium on the cultivation of bovine prospermatogonia from the cryopreserved tissues were examined. The testicular tissues of newborn bulls were well cryopreserved. High mRNA levels of prospermatogonium/SSC markers (PLZF, GFRα-1) and pluripotency markers (Oct4/Pouf5, Sox2, Nanog) were detected and the PLZF+/GFRα-1+ prospermatogonia were consistently identified immunohistochemically in the seminiferous cords. Using differential plating and Percoll-based centrifugation, 41.59% prospermatogonia were enriched and they proliferated robustly in 2i medium. The 2i medium boosted mRNA abundances of Pouf5, Sox2, Nanog, GFRα-1, PLZF, anti-apoptosis gene Bcl2, LIF receptor gene LIFR and enhanced PLZF protein expression, but suppressed mRNA expressions of spermatogonial differentiation marker c-kit and pro-apoptotic gene Bax, in the cultured prospermatogonia. It also alleviated H2O2-induced apoptosis of the enriched cells and decreased histone H3 lysine (K9) trimethylation (H3K9me3) and its methylase Suv39h1/2 mRNA level in the cultured seminiferous cords. Overall, 2i medium improves the cultivation of bovine prospermatogonia isolated from the cryopreserved testes, by inhibiting Suv39h1/2-mediated H3K9me3 through Mek1/2 and Gsk3β signalling, evidencing successful cryopreservation and expansion of bovine germplasm.  相似文献   
74.
Smokers are at a higher risk of delayed union or nonunion after fracture repair. Few specific interventions are available for prevention because the molecular mechanisms that result in these negative sequelae are poorly understood. Murine models that mimic fracture healing in smokers are crucial in further understanding the local cellular and molecular alterations during fracture healing caused by smoking. We exposed three murine strains, C57BL/6J, 129X1/SvJ, and BALB/cJ, to cigarette smoke for 3 months before the induction of a midshaft transverse femoral osteotomy. We evaluated fracture healing 4 weeks after the osteotomy using radiography, micro-computed tomography (μCT), and biomechanical testing. Radiographic analysis demonstrated a significant decrease in the fracture healing capacity of smoking 129X1/SvJ mice. μCT results showed delayed remodeling of fracture calluses in all three strains after cigarette smoke exposure. Biomechanical testing indicated the most significant impairment in the functional properties of 129X1/SvJ in comparison with C57BL/6J and BALB/cJ mice after cigarette smoke exposure. Thus, the 129X1/SvJ strain is most suitable in simulating smoking-induced impaired fracture healing. Furthermore, in smoking 129X1/SvJ murine models, we investigated the molecular and cellular alterations in fracture healing caused by cigarette smoking using histology, flow cytometry, and multiplex cytokine/chemokine analysis. Histological analysis showed impaired chondrogenesis in cigarette smoking. In addition, the important reparative cell populations, including skeletal stem cells and their downstream progenitors, demonstrated decreased expansion after injury as a result of cigarette smoking. Moreover, significantly increased pro-inflammatory mediators and the recruitment of immune cells in fracture hematomas were demonstrated in smoking mice. Collectively, our findings demonstrate the significant cellular and molecular alterations during fracture healing impaired by smoking, including disrupted chondrogenesis, aberrant skeletal stem and progenitor cell activity, and a pronounced initial inflammatory response. © 2020 American Society for Bone and Mineral Research (ASBMR).  相似文献   
75.
76.
BackgroundA diverse physician workforce improves the quality of care for all patients, and there is a need for greater diversity in orthopaedic surgery. It is important that medical students of diverse backgrounds be encouraged to pursue the specialty, but to do so, we must understand students’ perceptions of diversity and inclusion in orthopaedics. We also currently lack knowledge about how participation in an orthopaedic clinical rotation might influence these perceptions.Questions/purposes(1) How do the perceptions of diversity and inclusion in orthopaedic surgery compare among medical students of different gender identities, races or ethnicities, and sexual orientations? (2) How do perceptions change after an orthopaedic clinical rotation among members of demographic groups who are not the majority in orthopaedics (that is, cis-gender women, underrepresented racial minorities, other racial minorities, and nonheterosexual people)?MethodsWe surveyed students from 27 US medical schools who had completed orthopaedic rotations. We asked about their demographic characteristics, rotation experience, perceptions of diversity and inclusion in orthopaedics, and personal views on specialty choice. Questions were derived from diversity, equity, and inclusion climate surveys used at major academic institutions. Cis-gender men and cis-gender women were defined as those who self-identified their gender as men or women, respectively, and were not transgender. Forty-five percent (59 of 131) of respondents were cis-men and 53% (70 of 131) were cis-women; 49% (64 of 131) were white, 20% (26 of 131) were of underrepresented racial minorities, and 31% (41 of 131) were of other races. Eighty-five percent (112 of 131) of respondents were heterosexual and 15% (19 of 131) reported having another sexual orientation. We compared prerotation and postrotation perceptions of diversity and inclusion between majority and nonmajority demographic groups for each demographic domain (for example, cis-men versus cis-women). We also compared prerotation to postrotation perceptions within each nonmajority demographic group. To identify potential confounding variables, we performed univariate analysis to compare student and rotation characteristics across the demographic groups, assessed using an alpha of 0.05. No potential confounders were identified. Statistical significance was assessed at a Bonferroni-adjusted alpha of 0.0125. Our estimated response percentage was 26%. To determine limitations of nonresponse bias, we compared all early versus late responders and found that for three survey questions, late responders had a more favorable perception of diversity in orthopaedic surgery, whereas for most questions, there was no difference.ResultsBefore rotation, cis-women had lower agreement that diversity and inclusion are part of orthopaedic culture (mean score 0.96 ± 0.75) compared with cis-men (1.4 ± 1.1) (mean difference 0.48 [95% confidence interval 0.16 to 0.81]; p = 0.004), viewed orthopaedic surgery as less diverse (cis-women 0.71 ± 0.73 versus cis-men 1.2 ± 0.92; mean difference 0.49 [95% CI 0.20 to 0.78]; p = 0.001) and more sexist (cis-women 1.3 ± 0.92 versus cis-men 1.9 ± 1.2; mean difference 0.61 [95% CI 0.23 to 0.99]; p = 0.002), believed they would have to work harder than others to be valued equally (cis-women 2.8 ± 1.0 versus cis-men 1.9 ± 1.3; mean difference 0.87 [95% CI 0.45 to 1.3]; p < 0.001), and were less likely to pursue orthopaedic surgery (cis-women 1.4 ± 1.4 versus cis-men 2.6 ± 1.1; mean difference 1.2 [95% CI 0.76 to 1.6]; p < 0.001). Before rotation, underrepresented minorities had less agreement that diversity and inclusion are part of orthopaedic surgery culture (0.73 ± 0.72) compared with white students (1.5 ± 0.97) (mean difference 0.72 [95% CI 0.35 to 1.1]; p < 0.001). Many of these differences between nonmajority and majority demographic groups ceased to exist after rotation. Compared with their own prerotation beliefs, after rotation, cis-women believed more that diversity and inclusion are part of orthopaedic surgery culture (prerotation mean score 0.96 ± 0.75 versus postrotation mean score 1.2 ± 0.96; mean difference 0.60 [95% CI 0.22 to 0.98]; p = 0.002) and that orthopaedic surgery is friendlier (prerotation 2.3 ± 1.2 versus postrotation 2.6 ± 1.1; mean difference 0.41 [95% CI 0.14 to 0.69]; p = 0.004), more diverse (prerotation 0.71 ± 0.73 versus postrotation 1.0 ± 0.89; mean difference 0.28 [95% CI 0.08 to 0.49]; p = 0.007), less sexist (prerotation 1.3 ± 0.92 versus postrotation 1.9 ± 1.0; mean difference 0.63 [95% CI 0.40 to 0.85]; p < 0.001), less homophobic (prerotation 2.1 ± 1.0 versus postrotation 2.4 ± 0.97; mean difference 0.27 [95% CI 0.062 to 0.47]; p = 0.011), and less racist (prerotation 2.3 ± 1.1 versus postrotation 2.5 ± 1.1; mean difference 0.28 [95% CI 0.099 to 0.47]; p = 0.003). Compared with before rotation, after rotation cis-women believed less that they would have to work harder than others to be valued equally on the rotation (prerotation 2.8 ± 1.0 versus postrotation 2.5 ± 1.0; mean difference 0.31 [95% CI 0.12 to 0.50]; p = 0.002), as did nonheterosexual students (prerotation 2.4 ± 1.4 versus postrotation 1.8 ± 1.3; mean difference 0.56 [95% 0.21 to 0.91]; p = 0.004). Underrepresented minority students saw orthopaedic surgery as less sexist after rotation compared with before rotation (prerotation 1.5 ± 1.1 versus postrotation 2.0 ± 1.1; mean difference 0.52 [95% CI 0.16 to 0.89]; p = 0.007).ConclusionEven with an estimated 26% response percentage, we found that medical students of demographic backgrounds who are not the majority in orthopaedics generally perceived that orthopaedic surgery is less diverse and inclusive than do their counterparts in majority groups, but these views often change after a clinical orthopaedic rotation.Clinical RelevanceThese perceptions may be a barrier to diversification of the pool of medical student applicants to orthopaedics. However, participation in an orthopaedic surgery rotation is associated with mitigation of many of these negative perceptions among diverse students. Medical schools have a responsibility to develop a diverse workforce, and given our findings, schools should promote participation in a clinical orthopaedic rotation. Residency programs and orthopaedic organizations can also increase exposure to the field through the rotation and other means. Doing so may ultimately diversify the orthopaedic surgeon workforce and improve care for all orthopaedic patients.  相似文献   
77.
78.
79.
Zhang  Junjun  Wang  Yongli  Liu  Zhangsuo  Huang  Bo  Wang  Xutong  Xie  Minhua  Yu  Dan  Guo  Ruxue  Wang  Panfei 《Clinical and experimental nephrology》2021,25(8):865-874
Clinical and Experimental Nephrology - In this study, we investigated the clinical and pathologic characteristics and prognosis of overlapping obesity-related glomerulopathy (ORG) and...  相似文献   
80.
In 54 cases of ruptured medial semilunar cartilages of the knee joint the bone mineral mass in the distal end of the femur was measured 0–5 years following removal of the injured cartilage. The bone mineral mass was significantly decreased. There was no tendency of restoration of the bone mass with time.Financial support was obtained from the Swedish Medical Research Council No: K69-23X-2737-01 and from the Gustav V 80: th Anniversary Foundation.  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