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   1275642篇
  免费   94307篇
  国内免费   1986篇
耳鼻咽喉   18274篇
儿科学   42287篇
妇产科学   37821篇
基础医学   187126篇
口腔科学   35393篇
临床医学   108185篇
内科学   251381篇
皮肤病学   26516篇
神经病学   99280篇
特种医学   50002篇
外国民族医学   366篇
外科学   197693篇
综合类   26506篇
现状与发展   1篇
一般理论   300篇
预防医学   92569篇
眼科学   29045篇
药学   97889篇
  1篇
中国医学   2500篇
肿瘤学   68800篇
  2018年   11842篇
  2015年   11658篇
  2014年   16032篇
  2013年   24412篇
  2012年   33632篇
  2011年   36036篇
  2010年   21264篇
  2009年   20066篇
  2008年   35067篇
  2007年   38032篇
  2006年   38562篇
  2005年   37874篇
  2004年   36441篇
  2003年   35437篇
  2002年   34962篇
  2001年   58112篇
  2000年   59599篇
  1999年   50700篇
  1998年   14238篇
  1997年   12815篇
  1996年   13081篇
  1995年   12356篇
  1994年   11769篇
  1993年   10867篇
  1992年   40989篇
  1991年   40361篇
  1990年   39892篇
  1989年   38707篇
  1988年   36112篇
  1987年   35353篇
  1986年   33728篇
  1985年   32141篇
  1984年   23925篇
  1983年   20819篇
  1982年   12378篇
  1981年   10929篇
  1980年   10204篇
  1979年   22635篇
  1978年   15879篇
  1977年   13730篇
  1976年   12971篇
  1975年   14203篇
  1974年   16683篇
  1973年   16077篇
  1972年   15320篇
  1971年   14229篇
  1970年   13214篇
  1969年   12731篇
  1968年   11978篇
  1967年   10478篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
111.
112.
113.
Die Ophthalmologie - Die Filtrationsverfahren sind im Gegensatz zu allen anderen Glaukomoperationen mit einer biomikroskopisch sichtbaren Wundheilung assoziiert, sodass eine Vielzahl von...  相似文献   
114.
Background and aimsDespite using sensor-augmented pump therapy (SAPT) with predictive low-glucose management (PLGM), hypoglycemia is still an issue in patients with type 1 Diabetes (T1D). Our aim was to determine factors associated with clinically significant hypoglycemia (<54 mg/dl) in persons with T1D treated with PLGM-SAPT.Methodology: This is a multicentric prospective real-life study performed in Colombia, Chile and Spain. Patients with T1D treated with PLGM-SAPT, using sensor ≥70% of time, were included. Data regarding pump and sensor use patterns and carbohydrate intake from 28 consecutive days were collected. A bivariate and multivariate Poisson regression analysis was carried out, to evaluate the association between the number of events of <54 mg/dl with the clinical variables and patterns of sensor and pump use.Results188 subjects were included (41 ± 13.8 years-old, 23 ± 12 years disease duration, A1c 7.2% ± 0.9). The median of events <54 mg/dl was four events/patient/month (IQR 1–10), 77% of these events occurred during day time. Multivariate analysis showed that the number of events of hypoglycemia were higher in patients with previous severe hypoglycemia (IRR1.38; 95% CI 1.19–1.61; p < 0.001), high glycemic variability defined as Coefficient of Variation (CV%) > 36% (IRR 2.09; 95%CI 1.79–2.45; p < 0.001) and hypoglycemia unawareness. A protector effect was identified for adequate sensor calibration (IRR 0.77; 95%CI 0.66–0.90; p:0.001), and the use of bolus wizard >60% (IRR 0.74; 95%CI 0.58–0.95; p:0.017).ConclusionIn spite of using advanced SAPT, clinically significant hypoglycemia is still a non-negligible risk. Only the identification and intervention of modifiable factors could help to prevent and reduce hypoglycemia in clinical practice.  相似文献   
115.
116.
117.
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
118.
119.
120.
Women with pre-eclampsia have an increased risk of cardiovascular disease later in life. The aim of the study was to establish the presence and pattern of arterial stiffness in women previously with pre-eclampsia from a semi-rural region of South Africa. This was a prospective longitudinal study which involved 36 previously pre-eclamptic women and 86 non-pregnant controls (NPC) who had a past history of non-complicated pregnancy. Maternal wave reflection (augmentation index) and carotid-femoral pulse wave velocity were assessed noninvasively, using applanation tonometry with the SphygmoCor device. Endothelial function was assessed by EndoPAT 2000 device; pneumatic probes were fitted to the index fingers; induced flow-mediated reactive hyperemia; the ratio of the readings before and after occlusion was then used to calculate the score, the reactive hyperemia index (RHI) as a measure of endothelial function.

Pulse wave velocity remained significantly higher in previously pre-eclamptic women than non-pregnant controls up to three months after delivery (p < 0.05), then it reduced to nonsignificant values. All blood pressure indices (central and brachial pressures), were higher in previously pre-eclamptic women as compared to nonpregnant controls up to one year postpartum.

Regional (aortic) arterial stiffness, though it persists for some time after delivery, is transitory in previously pre-eclamptic women from the rural Africa setting. However, their increase blood pressure is an indication of compromised arterial compliance in women previously with pre-eclampsia.  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