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   1458篇
  免费   113篇
  国内免费   66篇
耳鼻咽喉   5篇
儿科学   4篇
妇产科学   14篇
基础医学   197篇
口腔科学   19篇
临床医学   143篇
内科学   227篇
皮肤病学   5篇
神经病学   197篇
特种医学   67篇
外科学   181篇
综合类   175篇
预防医学   55篇
眼科学   29篇
药学   138篇
  1篇
中国医学   25篇
肿瘤学   155篇
  2024年   1篇
  2023年   131篇
  2022年   151篇
  2021年   118篇
  2020年   168篇
  2019年   80篇
  2018年   53篇
  2017年   81篇
  2016年   54篇
  2015年   56篇
  2014年   184篇
  2013年   98篇
  2012年   61篇
  2011年   80篇
  2010年   56篇
  2009年   78篇
  2008年   42篇
  2007年   27篇
  2006年   27篇
  2005年   13篇
  2003年   5篇
  2002年   1篇
  2001年   5篇
  2000年   3篇
  1999年   6篇
  1998年   7篇
  1997年   6篇
  1996年   12篇
  1995年   15篇
  1994年   3篇
  1993年   4篇
  1992年   1篇
  1991年   2篇
  1990年   3篇
  1989年   5篇
排序方式: 共有1637条查询结果,搜索用时 31 毫秒
1.
2.
Background: Pulmonary manifestations of systemic lupus erythematosus (SLE) are appearing in 4-5% of patients involving lung in almost half of the cases during the disease course. Objective: We compared the autoimmune pulmonary inflammation in the lung tissue of mice to determine the association between decreased expression levels of Forkhead Box J1 (FOXJ1) and the activation of the NF-κB pathway in autoimmune pulmonary inflammation of MRL/Lpr mice. Methods: The female BALB/c mice (n=6) and MRL/Lpr mice (n=30) were divided into 5 groups including a control group (BALB/c), and five MRL/Lpr mice groups (8W, 12W, 16W, 24W, and 32W). The infiltration of the inflammatory cells was determined in lung tissue by performing the histological analysis. The western blotting was used to examine the expression levels of the age-related FOXJ1, and p50 and p65 proteins in the lungs of MRL/Lpr mice. The expression levels of MMP2 and MMP9 were determined via immunohistochemistry and immunofluorescence. Results: There were severe infiltrates of lung cells with high levels of tracheal damage, perivascular injury and interstitial inflammatory cell infiltration when the MRL/Lpr mice from 16w to 32w comparing to the 8w old healthy MRL/Lpr mice in the control group (p <0.05). Moreover, the reduced expression levels of FOXJ1 were associated with the activation of the NF-κB pathway in interstitial lung disease of MRL/Lpr mice via the modulation of p50 and p65. In addition, the expression levels of MMP2 and MMP9 pro-inflammation factors increased in the lungs of the MRL/Lpr mice from 16w to 32w. Conclusions: The expression level of FOXJ1 might be an indicator of the degree of lung disease in lupus-prone mice.  相似文献   
3.
4.
5.
6.
Cerebral blood volume flow and flow velocity have been reported to increase during dynamic exercise, but whether the two increase in parallel and whether both increases occur as functions of exercise intensity remain unsettled. In this study, blood flow velocity in the common carotid artery was measured using the Doppler ultrasound method in eight healthy male students during graded treadmill exercise. The exercise consisted of stepwise progressive increases and decreases in exercise intensity. The peak intensity corresponded to approximately 85% of maximal oxygen consumption. During this exercise, the heart rate (f c), mean blood pressure (BP) in the brachial artery and mean blood flow velocity (cc) in the common carotid artery increased as functions of exercise intensity. At the peak exercise intensity, (f c), BP and cc increased by 134.5%, 20.5% and 51.8% over the control levels before exercise (P < 0.01), respectively. The resistance index (RI) and pulsatility index (PI) were determined from the velocity profile and were expected to reflect the distal cerebral blood flow resistance. The RI and PI increased during the graded exercise, but tended to decrease at the highest levels of exercise intensity. As cc increased with increases in exercise intensity it would be expected that cerebral blood flow would also increase at these higher intensities. It is also suggested that blood flow velocity in the cerebral artery does not proportionately reflect the cerebral blood flow during dynamic exercise, since the cerebral blood flow resistance changes.  相似文献   
7.
目的探讨电解脱弹簧圈(Guglialm i detachab le coil,GDC)颅内动脉瘤栓塞术中动脉瘤再破裂的发生率、原因、对策及结果。方法302例颅内动脉瘤破裂患者行GDC栓塞术,其中8例发生术中动脉瘤再破裂。结果2例由微导丝穿破动脉瘤壁引起,3例由微导管穿破动脉瘤壁引起,2例由置放首枚弹簧圈时顶破动脉瘤壁引起,l例术中自发破裂,所有病例均继续行GDC动脉瘤填塞。2例死于动脉瘤破裂后大出血,其他6例均康复没有留下后遗症。本组术中动脉瘤再破裂发生率为2.6%,死亡率为25%。结论GDC血管内栓塞术中引起动脉瘤再破裂是十分少见的,但大部分病例经过继续填塞GDC可达到完全填塞动脉瘤,且不留下后遗症。  相似文献   
8.
目的 探讨切割穹窿海马伞及脑室给予神经生长因子(NGF)后,对大鼠海马自体神经干细胞增殖和分化为神经元的影响.方法 12只SD大鼠,随机分成给药组和对照组,每组6只,切割右侧穹窿海马伞,两组切割后即时及第2d、4d向侧脑室分别注射NGF和人工脑脊液, 并在术后第3~7d每日腹腔注射2次BrdU.于术后28d灌注取脑、冷冻切片,行BrdU/NF-200免疫荧光双标检测.结果 海马齿状回内BrdU阳性细胞数,给药组和对照组切割侧明显多于正常侧,给药组切割侧和正常侧分别多于对照组切割侧和正常侧;海马齿状回内的BrdU/NF-200双标神经元数,给药组切割侧最多,给药组正常侧和对照组切割侧较少,而对照组正常侧则无.结论 切割穹窿海马伞后,可致大鼠海马齿状回自体神经干细胞增殖加快并向神经元分化,脑室施加 NGF可促进其增殖和分化.  相似文献   
9.
《Acta histochemica》2023,125(5):152046
The close interaction between male germ cells and Sertoli cells, a type of somatic cell found in the seminiferous tubules of mammalian testis, is essential for the normal progression of spermatogenesis in mammals. Vimentin is an intermediate filament protein that primarily provides mechanical support, preserves cell shape, and maintains the nuclear position, and it is often used as a marker to identify Sertoli cells. Vimentin is known to be involved in many diseases and aging processes; however, how vimentin is related to spermatogenic dysfunction and the associated functional changes is still unclear. In a previous study, we reported that vitamin E deficiency affected the testes, epididymis, and spermatozoa of mice, accelerating the progression of senescence. In this study, we focused on the Sertoli cell marker vimentin and explored the relationship between the cytoskeletal system of Sertoli cells and spermatogenic dysfunction using testis tissue sections that caused male reproductive dysfunction with vitamin E deficiency. The immunohistochemical analysis showed that the proportion of the vimentin-positive area in seminiferous tubule cross-sections was significantly increased in testis tissue sections of the vitamin E-deficient group compared with the proportion in the control group. The histological analysis of testis tissue sections from the vitamin E-deficient group showed that vimentin-positive Sertoli cells were greatly extended from the basement membrane, along with an increased abundance of vimentin. These findings suggest that vimentin may be a potential indicator for detecting spermatogenic dysfunction.  相似文献   
10.
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