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   129002篇
  免费   11261篇
  国内免费   6691篇
耳鼻咽喉   1225篇
儿科学   1962篇
妇产科学   2931篇
基础医学   13469篇
口腔科学   2679篇
临床医学   16039篇
内科学   20187篇
皮肤病学   1593篇
神经病学   6402篇
特种医学   4211篇
外国民族医学   40篇
外科学   13353篇
综合类   19320篇
现状与发展   20篇
一般理论   18篇
预防医学   9435篇
眼科学   3449篇
药学   13515篇
  115篇
中国医学   6565篇
肿瘤学   10426篇
  2024年   347篇
  2023年   1716篇
  2022年   4018篇
  2021年   5457篇
  2020年   4061篇
  2019年   3705篇
  2018年   3943篇
  2017年   3708篇
  2016年   3310篇
  2015年   5240篇
  2014年   6736篇
  2013年   6949篇
  2012年   10130篇
  2011年   10874篇
  2010年   7489篇
  2009年   6158篇
  2008年   7784篇
  2007年   7775篇
  2006年   7320篇
  2005年   6691篇
  2004年   4842篇
  2003年   4402篇
  2002年   3652篇
  2001年   3095篇
  2000年   2847篇
  1999年   2644篇
  1998年   1326篇
  1997年   1233篇
  1996年   993篇
  1995年   962篇
  1994年   889篇
  1993年   514篇
  1992年   894篇
  1991年   804篇
  1990年   674篇
  1989年   575篇
  1988年   535篇
  1987年   453篇
  1986年   357篇
  1985年   286篇
  1984年   184篇
  1983年   167篇
  1982年   95篇
  1981年   94篇
  1979年   140篇
  1978年   111篇
  1977年   83篇
  1974年   94篇
  1973年   72篇
  1972年   87篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
BACKGROUND AND PURPOSE: Taiwan's National Health Insurance (NHI) program has considered the use of capitation payments to health care providers as a method for control of the rising costs of the system. The establishment of capitation payments usually requires the performance of risk adjustment. The purposes of this study were to develop a diagnosis-based risk adjustment model for the NHI and to evaluate its predictability. METHODS: Using a 2% random sample of 371,620 NHI enrollees, the authors developed a Taiwan version of the Principal Inpatient Diagnosis Cost Groups (TPIPDCGs) from 1996 claim records to predict an individual's expenditure in 1997. Weighted least squares regression models were built in an estimation sample (two-thirds of the study sample), and were cross-validated in a validation sample (the remaining one-third of the study sample). Predictive R2 and predictive ratios were used to evaluate the model's predictability. RESULTS: Only 7.88% of the study sample could be classified into 1 of the 16 TPIPDCGs. Combined with demographic variables, which alone could explain 3.7% of the variation in an individual's future expenditure, the risk adjustment model based on TPIPDCGs could explain 12.2% of expenditure variation. In addition, the finding that the predictive ratios of the TPIPDCG model approximated unity better than those of the demographic model in all subgroups indicates that the capitation payment as predicted by the TPIPDCG model for each subgroup would better correlate to the actual spending. CONCLUSION: Taiwan's risk-adjusted capitation model based on principal inpatient diagnoses has higher predictability on individual's future expenditure than its counterpart in the USA. This finding provides insight into not only the development of Taiwan's diagnosis-based risk adjustment models but also the necessity of modification when applying foreign-developed risk adjustment models to the NHI.  相似文献   
12.
Skin penetration of topically applied diclofenac is important for the treatment of rheumatic diseases and actinic keratoses. We have studied the permeation of diclofenac across human cadaver epidermis in-vitro from four lecithin vesicle formulations and a few marketed semi-solid preparations. The lecithin vesicle formulations were prepared by dissolving the lipid contents (lecithin and sodium cholate) in a 1:1 mixture of methanol-chloroform, evaporating the solvents under vacuum, and hydrating the lipid layer with the drug solution in water or 10% ethanol. The vesicles were sonicated for 5 min to reduce the vesicle size and their size and Zeta potential were characterized. The cumulative amount and maximum flux of diclofenac was 69.7+/-40.3 micrograms and 4.77+/-3.16 micrograms/hcm(2) from lecithin vesicles containing sodium cholate and 10% ethanol, and is the highest of all formulations studied. The cumulative amount and mean maximum flux obtained from other formulations were in the range of 2.46+/-1.98-29.9+/-10.1 micrograms and 0.53+/-0.46-3.61+/-0.86 micrograms/hcm(2). Based on the results, lecithin vesicles of diclofenac appear to be advantageous for the topical delivery of diclofenac.  相似文献   
13.
14.
Reduction of transmission of human immunodeficiency virus type 1 (HIV-1) through human milk is needed. Alkyl sulfates such as sodium dodecyl sulfate (SDS) are microbicidal against HIV-1 at low concentrations, have little to no toxicity, and are inexpensive. The authors have reported that treatment of HIV-1-infected human milk with < or = 1% (10 mg/mL) SDS for 10 minutes inactivates cell-free and cell-associated virus. The SDS can be removed with a commercially available resin after treatment without recovery of viral infectivity. In this article, the authors report results of selective biochemical analyses (ie, protein, immunoglobulins, lipids, cells, and electrolytes) of human milk subjected to SDS treatment and removal. The SDS treatment or removal had no significant effects on the milk components studied. Therefore, the use of alkyl sulfate microbicides to treat milk from HIV-1-positive women may be a simple, practical, and nutritionally sound way to prevent or reduce transmission of HIV-1 while still feeding with mother's own milk.  相似文献   
15.
16.
The neutral lipids existing in the intercellular spaces of the stratum corneum (SC) provide a permeability barrier to prevent water loss. Nile red is the most sensitive lipid stain for tissue sections. However, due to the extremely flattened morphology of corneocytes and the resolution limits of the light microscope, Nile red staining is seldom used as a fluorescent probe for the lipid-rich SC. In this study, we modified the traditional method for visualization of intracellular lipid by adding 4% potassium hydroxide after Nile red staining. This modified method not only allowed visualization of lipids existing in the intercellular membrane regions and the lateral junctions of the adjoining corneocytes, but also clearly demonstrated small lipid droplets within pathological corneocytes. These features were not observed with the traditional staining method. Thus, this modified Nile red staining method greatly improved the resolution of the SC lipids under light microscopy and should be useful for studying lipid depositions in both normal and pathological SC.  相似文献   
17.
The effect of olestra on vitamin D status was assessed in a 6-wk, double-blind, placebo-controlled study involving 202 free-living adults. Subjects consumed a total of 20 g/d of olestra or triglycerides in cookies eaten at each meal. A 20-micrograms ergocalciferol capsule was taken with each morning meal. Serum 25-hydroxyergocalciferol (25-OHD2) concentrations rose from approximately 5.7 to 39.0 and 31.7 nmol/L in the placebo and olestra groups, respectively, at week 6. At week 6, 25-OHD2 contributed 46-54% to total serum 25-OHD concentration compared with 11% at baseline. The 19% decrease in serum 25-OHD2 concentrations produced by olestra in this study is equivalent to a decrease of approximately 1.2 nmol/L under nonsupplemented dietary conditions. Ingesting 20 g olestra/d in the diet is thus not expected to affect vitamin D nutritional status.  相似文献   
18.
19.
The present study was undertaken to examine whether the second generation antibiotic drug minocycline attenuates behavioral changes (eg, acute hyperlocomotion and prepulse inhibition (PPI) deficits) in mice after the administration of the N-methyl-D-aspartate (NMDA) receptor antagonist (+)-MK-801 (dizocilpine). Dizocilpine (0.1 mg/kg)-induced hyperlocomotion was significantly attenuated by pretreatment with minocycline (40 mg/kg). Furthermore, the PPI deficits after a single administration of dizocilpine (0.1 mg/kg) were attenuated by pretreatment with minocycline (10, 20, or 40 mg/kg), in a dose-dependent manner. Moreover, in vivo microdialysis study in the free-moving mice revealed that pretreatment with minocycline (40 mg/kg, i.p.) significantly attenuated the increase of extracellular dopamine (DA) levels in the frontal cortex and striatum after administration of dizocilpine (0.1 mg/kg), suggesting that the inhibition of dizocilpine-induced DA release by minocycline may, at least in part, be implicated in the mechanism of action of minocycline with respect to dizocilpine-induced behavioral changes in mice. These findings suggest that minocycline could attenuate behavioral changes in mice after the administration of the NMDA receptor antagonist dizocilpine. Therefore, it is possible that minocycline would be a potential therapeutic drug for schizophrenia.  相似文献   
20.
High cord blood immunoglobulin E (cbIgE) is known to be associated with increased risks of atopic diseases in childhood. The relationship between genetic polymorphisms and high cbIgE has not been well documented. A cross-sectional study was conducted to assess the association between cbIgE and genetic polymorphisms of interleukin (IL)-4 -590C/T, the beta-subunit of the high-affinity receptor for IgE (FcepsilonRI-beta) E237G, lymphotoxin (LT)-alphaNcoI alleles, and tumor necrosis factor (TNF)-alpha -308G/A. A total of 320 mother-neonate pairs were recruited from four maternity hospitals from different locations of Taiwan. Cord blood was obtained and assayed for cbIgE. Polymerase chain reaction followed by restriction fragment length polymorphism was used to assess the genotypes. Three hundred pairs of mothers and neonates were included in the final analysis. Infants with IL-4 -590 C allele were found to have higher risk of elevated cbIgE (> or =0.35 IU/ml, 24.3%) (p = 0.004). After adjusting for gender, birth order, maternal age, and history of allergic disease in maternal and paternal families, odds ratios for CC and CT genotypes were 4.41 and 3.16 (95% confidence interval 0.78-22.67, and 1.66-6.13), respectively, using TT genotype as reference. The genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha were not associated with cbIgE before or after the adjustment. Our finding suggested a significant association of cbIgE with genetic polymorphism of IL-4 -590C/T, but not with the genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha.  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