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   23106篇
  免费   1478篇
  国内免费   150篇
耳鼻咽喉   305篇
儿科学   643篇
妇产科学   668篇
基础医学   3674篇
口腔科学   343篇
临床医学   2208篇
内科学   4447篇
皮肤病学   588篇
神经病学   2291篇
特种医学   1274篇
外国民族医学   8篇
外科学   3243篇
综合类   189篇
一般理论   11篇
预防医学   1521篇
眼科学   537篇
药学   1590篇
中国医学   60篇
肿瘤学   1134篇
  2022年   168篇
  2021年   327篇
  2020年   226篇
  2019年   307篇
  2018年   389篇
  2017年   319篇
  2016年   431篇
  2015年   432篇
  2014年   530篇
  2013年   644篇
  2012年   1063篇
  2011年   1109篇
  2010年   595篇
  2009年   575篇
  2008年   898篇
  2007年   1009篇
  2006年   993篇
  2005年   972篇
  2004年   891篇
  2003年   841篇
  2002年   831篇
  2001年   805篇
  2000年   721篇
  1999年   671篇
  1998年   294篇
  1997年   248篇
  1996年   216篇
  1995年   209篇
  1994年   176篇
  1993年   177篇
  1992年   391篇
  1991年   375篇
  1990年   419篇
  1989年   384篇
  1988年   357篇
  1987年   396篇
  1986年   355篇
  1985年   351篇
  1984年   259篇
  1983年   213篇
  1979年   251篇
  1978年   207篇
  1977年   181篇
  1975年   170篇
  1974年   185篇
  1973年   181篇
  1972年   211篇
  1971年   188篇
  1969年   169篇
  1967年   169篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
31 female patients suffering from androgentic alopecia were examined by means of the TRH test with regard to hypothyroidism and hyperprolactinemia. Before, as well as 20 and 40 minutes after, application of thyroxine releasing hormone (TRH), the serum concentrations of the hypohyseal thyroxine stimulating hormone (TSH) and prolactin (PRL) were measured by radioimmunoassay (RIA). In 7 of the patients (23%), we found increased TSH levels after stimulation with TRH--indicative of hypothyroidism. In 9 of the patients (29%), we observed increased PRL levels after TRH stimulation, indicating prolactinemia. TSH and PRL can interact with androgen metabolism at various levels. Thyroxine may influence the unbound, metabolically active testosterone via the sex hormone binding globulin (SHBG). Prolactine, which is stimulated by TRH, promotes the suprarenal cortisol and androgen production. In 48% of the patients, we found either hypothyroidism or hyperprolactinemia. This suggests that both conditions may contribute to the clinical picture of female androgenetic alopecia, as they interfere with the androgen metabolism.  相似文献   
82.
83.
Positive affect predicts improved lip movement in facial movement disorder.   总被引:1,自引:0,他引:1  
OBJECTIVES: Positive affect in individuals with a facial movement disorder may promote lip corner movement (zygomaticus major) during smiling. We investigated whether a positive affect marker (orbicularis oculi activity) observed in an initial clinic visit of individuals with facial movement disorder (N = 28) predicted increased lip corner movement at a subsequent visit. STUDY DESIGN AND SETTING: In this clinical outcomes study, lip corner movement was assessed with the use of automated facial analysis. Asymmetry of movement was compared in individuals who smiled with or without the positive affect marker at an initial clinic visit. RESULTS: The positive affect marker at the initial visit was associated with a reduction in the asymmetry of the lip corner movement at the second visit. CONCLUSION: Positive affect predicts improved facial movement outcomes in patients with facial movement disorders. SIGNIFICANCE: Positive emotion in facial movement patients may be an important factor in recovery of facial movement during therapy.  相似文献   
84.
85.
86.
87.
Summary The principle of prebending plates is recommended for intertrochanteric osteotomies to reach satisfactory primary stability. This can be done by conventional or functional prebending. Because of the shape of an overbent plate in conventional prebending, when the tension device is used a sliding of the medial wedge of the proximal fragment medially on the distal osteotomy plane takes place. In functional prebending, the final shape of the plate results in almost no movement of the bone fragments. Therefore the measurable interfragmentary compression of functional prebending is better than in the conventional procedure. The functional prebending also causes no loss of primary installed medialisation and there is no need for an additional- procedure for the prebending during the operation.  相似文献   
88.
BACKGROUND.: There is agreement that a family history of hypertension (HT),is a predictor for the risk of diabetic nephropathy (DN) inpatients with type 2 diabetes, and possibly also type 1 diabetes.It follows that genes related to the risk of hypertension mustalso be considered candidate genes for DN. The 235T allele ofthe angiotensinogen gene was found to be related to primaryHT. METHODS.: To examine whether it is predictive for DN as well, we examinedthe angiotensinogen gene polymorphism in 230 healthy local controls,423 patients with type 1 diabetes (n=180 with DN; n=243 withoutDN) and 663 patients with type 2 diabetes (n=310 with DN; n=353without DN). The angiotensinogen gene M235T polymorphism wasdetermined using PCR amplification. RESULTS.: The following results were obtained (i) no significant differenceof genotype distribution (type 1: MM/MT/TT(%) 27.6/57.2/15.2vs. 27.2/56.1/16.7 (P=0.92); type 2: MM/MT/TT (%) 31.7/48.2/20.1vs. 32.9/46.8/20.3 (P=0.93)) or allele frequencies (type 1:M 0.56 vs. 0.55 (P=0.795); type 2: M 0.56 vs. 0.56 (P=0.86))was found, between diabetic patients with or without DN, (ii)no difference was found between normotensive and hypertensivediabetic patients. CONCLUSION.: The data argue against a role of the angiotensinogen gene M235Tpolymorphism in the manifestation of diabetic nephropathy orhypertension in diabetic patients.  相似文献   
89.
90.
Hepatitis has been considered, classically, as a diffuse hepatocellular necrosis, and little attention has been paid to the relationship of lesions to the microvasculature. In livers of mice (Balbc/J) infected with murine hepatitis virus (MHV-3), microcorrosion casts showed spherical cavities where casting compound was unable to fill sinusoids. At 48 hr postinfection such "lesions" had a mean diameter of 83 micron +/- 26 (SD) and their number/mm2 (at the surface of casts) was 0.95 +/- 1.3. Blind-ended sinusoids formed a distinct boundary between perfused and nonperfused areas, and concave impressions at their ends indicated cells blocking the lumen. In vivo microscopy of transilluminated livers in infected mice showed localized rounded areas without flow, corresponding to lesions seen in casts. RBC velocity measurements in sinusoids adjacent to lesions demonstrated that velocities fall from normal values to zero over a narrow border zone. Beginning with the most proximal sinusoid with visible flow and moving outward from the lesion to the second and third sinusoids, mean RBC velocities (micron/sec, +/- SD) were 17.4 +/- 6.7, 33.9 +/- 8.7, 66.6 +/- 27.3, respectively; this last value was not significantly different from velocities in normal liver (69.2 +/- 30.6). Transmission electron microscopy of livers of infected mice confirmed the presence of sinusoidal lumens blocked by protruding lining cells, RBCs, platelets, swollen hepatocytes, and cellular debris. This study demonstrates that the lesions are focal in origin, microvascular blockage leading to gradually increasing necrosis in all directions.  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