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   127619篇
  免费   7496篇
  国内免费   722篇
耳鼻咽喉   1175篇
儿科学   4189篇
妇产科学   2945篇
基础医学   18294篇
口腔科学   4192篇
临床医学   12334篇
内科学   28577篇
皮肤病学   3151篇
神经病学   12603篇
特种医学   2839篇
外国民族医学   1篇
外科学   11371篇
综合类   522篇
一般理论   73篇
预防医学   13048篇
眼科学   1953篇
药学   8836篇
中国医学   450篇
肿瘤学   9284篇
  2024年   135篇
  2023年   1222篇
  2022年   2540篇
  2021年   4349篇
  2020年   2747篇
  2019年   3781篇
  2018年   4202篇
  2017年   3181篇
  2016年   3697篇
  2015年   4077篇
  2014年   5317篇
  2013年   6956篇
  2012年   10663篇
  2011年   11034篇
  2010年   5991篇
  2009年   5047篇
  2008年   8755篇
  2007年   8778篇
  2006年   8186篇
  2005年   7611篇
  2004年   6863篇
  2003年   6092篇
  2002年   5485篇
  2001年   662篇
  2000年   457篇
  1999年   731篇
  1998年   964篇
  1997年   771篇
  1996年   669篇
  1995年   567篇
  1994年   505篇
  1993年   431篇
  1992年   329篇
  1991年   238篇
  1990年   230篇
  1989年   223篇
  1988年   209篇
  1987年   169篇
  1986年   192篇
  1985年   142篇
  1984年   175篇
  1983年   153篇
  1982年   178篇
  1981年   141篇
  1980年   142篇
  1979年   82篇
  1978年   95篇
  1977年   82篇
  1976年   83篇
  1974年   62篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
The aim of our study was to investigate the metabolic effect of telmisartan and irbesartan in subjects treated with rosiglitazone, a well-known insulin-sensitizing drug, in order to clarify the direct metabolic effects of the two former drugs. Patients were enrolled, evaluated, and followed at 3 Italian centers. We evaluated 188 type 2 diabetic patients with metabolic syndrome (94 males and 94 females in total; 49 males and 46 females, aged 56+/-5, treated with telmisartan; and 45 males and 48 females, aged 55+/-4, treated with irbesartan). All had been diabetic for at least 6 months, and glycemic control by the maximum tolerated dietary changes and maximum tolerated dose of oral hypoglycemic agents had been attempted and failed in all cases. All patients took a fixed dose of rosiglitazone, 4 mg/day. We administered telmisartan (40 mg/day) or irbesartan (150 mg/day) in a randomized, controlled, double-blind clinical manner. We evaluated body mass index (BMI), glycemic control (HbA1c fasting plasma glucose and insulin levels [FPG, and FPI, respectively], and homeostasis model assessment [HOMA] index), lipid profile (total cholesterol [TC], low density lipoprotein-cholesterol [LDL-C], high density lipoprotein-cholesterol [HDL-C], and triglycerides [TG]), systolic and diastolic blood pressure (SBP and DBP), tumor necrosis factor-alpha (TNF-alpha), and leptin during the 12 months of this treatment. No BMI change was observed after 6 or 12 months in either group. Significant decreases in HbAlc and FPG were observed after 6 months in the telmisartan group, and after 12 months in both groups. The decrease in HbA1c and FPG at 12 months was statistically significant only in the telmisartan group. A significant decrease in FPI was observed at 12 months in both groups, and this decrease was significantly greater in the telmisartan group. Significant decreases in the HOMA index were observed at 6 and 12 months in both groups, and the decrease in the HOMA index after 12 months was significantly greater in the telmisartan group than in the irbesartan group. Significant changes in SBP, DBP, TC, and LDL-C were observed after 6 and 12 months in both groups. Significant decreases in TNF-alpha and leptin levels were observed after 6 months in the telmisartan group, and after 12 months in both groups. In conclusion, in this study of patients with type 2 diabetes mellitus and metabolic syndrome, telmisartan seemed to result in a greater improvement in glycemic and lipid control and metabolic parameters related to metabolic syndrome compared to irbesartan. These observed metabolic effects of different angiotensin type 1 receptor blockers could be relevant when choosing a therapy to correct metabolic derangement of patients affected by metabolic syndrome and diabetes.  相似文献   
94.
95.
BACKGROUND/PURPOSE: The polysaccharide-rich composition of Aloe vera extracts (Aloe barbadensis Miller), often used in cosmetic formulations, may impart moisturizing properties to the product. The aim of this study was to evaluate the effect of cosmetic formulations containing different concentrations of freeze-dried Aloe vera extract on skin hydration, after a single and a 1- and 2-week period of application, by using skin bioengineering techniques. METHODS: Stable formulations containing 5% (w/w) of a trilaureth-4 phosphate-based blend were supplemented with 0.10%, 0.25% or 0.50% (w/w) of freeze-dried Aloe vera extract and applied to the volar forearm of 20 female subjects. Skin conditions in terms of the water content of the stratum corneum and of transepidermal water loss (TEWL) (Corneometer CM 825 and Tewameter TM 210) were analysed before and after a single and 1- and 2-week period of daily application. RESULTS: After a single application, only formulations supplemented with 0.25% and 0.50% (w/w) of Aloe vera extract increased the water content of the stratum corneum, while after the 2-week period application, all formulations containing the extract (0.10%, 0.25% and 0.50%) had the same effect, in both cases as compared with the vehicle. TEWL was not modified after a single and after 1- and 2-week period of application, when compared with the vehicle. CONCLUSION: Our results show that freeze-dried Aloe vera extract is a natural effective ingredient for improving skin hydration, possibly through a humectant mechanism. Consequently, it may be used in moisturizing cosmetic formulations and also as a complement in the treatment of dry skin.  相似文献   
96.
97.
In vivo diagnosis with cancer-specific targeting agents that have optimal characteristics for imaging is an important development in treatment planning for cancer patients. Overexpression of the HER2 antigen is high in several types of carcinomas and has predictive and prognostic value, especially for breast cancer. A new type of targeting agent, the Affibody molecule, was described recently. An Affibody dimer, His6-(ZHER2:4)2 (15.4 kDa), binds to HER2 with an affinity of 3 nmol/L and might be used for the imaging of HER2 expression. The use of 99mTc might improve the availability of the labeled conjugate, and Tc(I)-carbonyl chemistry enables the site-specific labeling of the histidine tag on the Affibody molecule. The goals of the present study were to prepare 99mTc-labeled His6-(ZHER2:4)2 and to evaluate its targeting properties compared with the targeting properties of 125I-4-iodobenzoate-His6-(ZHER2:4)2 [125I-His6-(ZHER2:4)2]. METHODS: The labeling of His6-(ZHER2:4)2 with 99mTc was performed with an IsoLink kit. The specificity of 99mTc-His6-(ZHER2:4)2 binding to HER2 was evaluated in vitro with SK-OV-3 ovarian carcinoma cells. The comparative biodistributions of 99mTc-His6-(ZHER2:4)2 and 125I-His6-(ZHER2:4)2 in tumor-bearing BALB/c nu/nu mice were determined. RESULTS: The labeling yield for 99mTc-His6-(ZHER2:4)2 was approximately 60% (50 degrees C), and the radiochemical purity was greater than 97%. The conjugate was stable during storage and under histidine and cysteine challenges and demonstrated receptor-specific binding. The biodistribution study demonstrated tumor-specific uptake levels (percentage injected activity per gram of tissue [%IA/g]) of 2.6 %IA/g for 99mTc-His6-(ZHER2:4)2 and 2.3 %IA/g for 125I-His6-(ZHER2:4)2 at 4 h after injection. Both conjugates provided clear imaging of SK-OV-3 xenografts at 6 h after injection. The tumor-to-nontumor ratios were much more favorable for the radioiodinated Affibody. CONCLUSION: The use of Tc(I)-carbonyl chemistry enabled us to prepare a stable, site-specifically labeled 99mTc-His6-(ZHER2:4)2 conjugate that was able to bind to HER2-expressing cells in vitro and in vivo. The indirectly radioiodinated conjugate provided better tumor-to-liver ratios. The labeling of Affibody molecules with 99mTc should be investigated further.  相似文献   
98.
OBJECTIVE: To examine the economic consequences of effective antihypertensive treatment using the novel vasodilating beta1-adrenoceptor antagonist nebivolol (Nebilet) from the perspective of the healthcare provider. METHODS: The evaluation was based on a postmarketing surveillance study in Germany involving 8682 moderately hypertensive patients. Using the Framingham Risk Model, the antihypertensive effectiveness of nebivolol after 6 weeks of treatment was extrapolated to estimate the reductions in 10-year risks of cardiovascular events. Data sources included direct costs for medical and invasive cardiovascular interventions in Germany, costs of therapy in the US and the UK, and estimates on the prevalence of cardiovascular events issued by the American Heart Association. RESULTS: Six-week antihypertensive treatment resulted in a DBP reduction of 13.7 mm Hg. The rate of responders, defined as those patients achieving DBP <90 mm Hg, was 70%. SBP was reduced by 26.1 mm Hg. According to the Framingham Risk Model, 313 deaths would be avoided. Coronary heart disease (CHD) could be reduced by 94 cases (from 1339 to 1245 events) and 150 strokes would be avoided (from 518 to 368 events) in a 10-year period. This reduction of 244 cardiovascular events among the 8682 patients investigated corresponded to cost savings of between Euro 250,000 and Euro 2.5 million, depending on the healthcare environment and the intervention applied. CONCLUSION: Treatment of moderately hypertensive patients with nebivolol can be considered cost effective. Nebivolol has the potential to decrease the overall long-term costs of medical care for patients with hypertension.  相似文献   
99.
Porcine small intestinal submucosa (SIS) is a cell-free collagen matrix that has demonstrated its ability as scaffold material for constructive remodeling of damaged or missing tissue. The purpose of this study was to evaluate the morphology and function of esophagoplasty in rat using a porcine SIS scaffold for the repair of a semi-circumferential defect in the cervical or in the abdominal esophagus. Sixty-seven rats underwent surgical excision of the anterior wall either of the cervical or of the abdominal esophagus and subsequent repair of the defect with an SIS patch graft. Outcomes of weight gain, signs of dysphagia, hematological and serum chemistry parameters, and barium swallow studies were used to assess the progress of healing and function over a 150-day time period. The grafts were studied for gross changes and histology at predetermined time points. Ninety-four percent of the SIS-treated rats survived, showing no significant differences in survival rate between groups. The grafted animals did well, without signs of dysphagia, and gaining weight. Barium swallow studies showed no evidence of fistula, significant stenosis, or diverticula. No hematological or serum biochemistry abnormalities were found. By 150 days, the SIS graft was replaced with esophageal-derived tissues. Specimens were completely lined by keratinized stratified squamous epithelium and showed complete regeneration of muscle fibers and scarce immunoreactivity for nerve. In the rat model, a patch graft technique using porcine SIS appears to induce esophageal regrowth either in cervical and abdominal esophagus. The repair mechanism occurred through a regenerative healing process.  相似文献   
100.
OBJECTIVE: This study analyzes the differences in psychological variables and symptomatology between temporomandibular disorder diagnosis subgroups. STUDY DESIGN: The sample included 114 temporomandibular disorder patients that were evaluated in coping, distress, and temporomandibular characteristics. Diagnostic muscular (n = 58) and articular (n = 56) subgroups were compared in these variables through a MANCOVA. RESULTS: Muscular patients show a higher level of general distress, specifically in the anxiety and somatization subscales and a more active coping style, with a tendency of a minor use of humor and a higher number of parafunctional habits, specifically, biting nails, hangnails, and lips. CONCLUSION: We discuss the differences found in order to design the targets of the psychological intervention of temporomandibular patients.  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