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   3860篇
  免费   269篇
  国内免费   40篇
耳鼻咽喉   35篇
儿科学   74篇
妇产科学   51篇
基础医学   473篇
口腔科学   149篇
临床医学   341篇
内科学   784篇
皮肤病学   72篇
神经病学   148篇
特种医学   107篇
外科学   527篇
综合类   117篇
一般理论   2篇
预防医学   387篇
眼科学   111篇
药学   445篇
中国医学   64篇
肿瘤学   282篇
  2024年   8篇
  2023年   62篇
  2022年   213篇
  2021年   316篇
  2020年   184篇
  2019年   159篇
  2018年   190篇
  2017年   145篇
  2016年   150篇
  2015年   175篇
  2014年   203篇
  2013年   217篇
  2012年   330篇
  2011年   344篇
  2010年   165篇
  2009年   117篇
  2008年   193篇
  2007年   176篇
  2006年   172篇
  2005年   144篇
  2004年   112篇
  2003年   107篇
  2002年   90篇
  2001年   12篇
  2000年   15篇
  1999年   18篇
  1998年   5篇
  1997年   5篇
  1996年   11篇
  1995年   7篇
  1994年   8篇
  1993年   3篇
  1992年   7篇
  1991年   8篇
  1990年   11篇
  1989年   9篇
  1988年   7篇
  1987年   5篇
  1986年   5篇
  1985年   8篇
  1984年   6篇
  1981年   3篇
  1979年   8篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1969年   3篇
  1967年   2篇
排序方式: 共有4169条查询结果,搜索用时 15 毫秒
21.
22.
This study was aimed to evaluate the efficacy of crude aqueous-methanol and aqueous extracts of neem (Azadirachta indica) seed kernel against sarcoptic mange of sheep. Crude aqueous-methanol (AME) and aqueous extracts (AE) of neem seed kernel (NSK) were prepared and formulated as 10% and 20% ointments (w/w), using Vaseline as vehicle. Forty-two lambs of Pak Karakul breed, having natural infection of sarcoptic mange were divided into seven experimental groups. Skin scrapings and clinical examination were carried out at scheduled intervals after treatment. Ivermectin (positive control) completely cleared infesting mites from animals after 10 days and 20% AME after 16 days. While, clinical mange was completely cured after 16 and 20 days with ivermectin and 20% AME, respectively, under field conditions. Only the higher concentration (20% AME) of NSK extracts completely cured the clinical mange, suggesting a dose-dependent response. Our results consolidate the belief that use of folk remedies can provide an effective and economic way of combating sarcoptic mange in sheep.  相似文献   
23.
In this study, we aimed to determine whether a postnatal trans fat diet (TFD) could aggravate prenatal bisphenol A (BPA) exposure effects on offspring’s small intestine and adulthood obesity, due to the relatively sparse findings on how the interaction between these two variables interrupt the small intestinal cells. Twelve pregnant rats were administered with either unspiked drinking water (control; CTL) or BPA-spiked drinking water throughout pregnancy. Twelve weaned pups from each pregnancy group were then given either a normal diet (ND) or TFD from postnatal week (PNW) 3 until PNW14, divided into control offspring on normal diet (CTL-ND), BPA-exposed offspring on normal diet (BPA-ND), control offspring on trans fat diet (CTL-TFD), and BPA offspring on trans fat diet (BPA-TFD) groups. Body weight (BW), waist circumference, and food and water intake were measured weekly in offspring. At PNW14, small intestines were collected for global DNA methylation and histological analyses. Marked differences in BW were observed starting at PNW9 in BPA-TFD (389.5 ± 10.0 g; p < 0.05) relative to CTL-ND (339.0 ± 7.2 g), which persisted until PNW13 (505.0 ± 15.6 g). In contrast, water and food intake between offspring were significantly different (p < 0.01–0.05) at earlier ages only (PNW4–6 and PNW7–9, respectively). Furthermore, substantial differences in the general parameters of the intestinal structures were exclusive to ileum crypt length alone, whereby both BPA-ND (150.5 ± 5.1 μm; p < 0.001), and BPA-TFD (130.3 ± 9.9 μm; p < 0.05) were significantly longer than CTL-ND (96.8 ± 8.9 μm). Moreover, BPA-ND (2.898 ± 0.147%; p < 0.05) demonstrated global small intestinal hypermethylation when compared to CTL-ND and CTL-TFD (1.973 ± 0.232% and 1.913 ± 0.256%, respectively). Prenatal BPA exposure may significantly affect offspring’s physiological parameters and intestinal function. Additionally, our data suggest that there might be compensatory responses to postnatal TFD in the combined BPA prenatal group (BPA-TFD).  相似文献   
24.
The Teleprimary Care—Oral Health Clinical Information System (TPC-OHCIS) is an updated electronic medical record (EMR) that has been applied in Malaysian primary healthcare. Recognizing the level of patient satisfaction following EMR implementation is crucial for assessing the performance of health care services. Hence, the main objective of this study was to compare the level of patient satisfaction between EMR-based clinics and paper-based clinics.The study was a quasi-experimental design that used a control group and was conducted among patients in 14 public primary healthcare facilities in the Seremban district of Malaysia from May 10, to June 30, 2021. Patient satisfaction was assessed using the validated Short-Form Patient Satisfaction Questionnaire, which consisted of 7 subscales. All data were analyzed using the IBM Statistical Package for Social Sciences version 21.A total of 321 patients consented to participate in this study, and 48.9% of them were from EMR clinics. The mean score for the communication subscale was the highest at 4.08 and 3.96 at EMR-adopted clinics and paper-based record clinics. There were significant differences in general satisfaction and communication subscales, with higher patient satisfaction found in clinics using EMR.With the utilization of EMR, patient satisfaction and communication in delivering healthcare services have improved.  相似文献   
25.
This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and Nhydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine.This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to conf...  相似文献   
26.
Steel fibers are widely extracted from scrap tyres, causing environmental concerns. This paper presents the use of steel fibers in variable proportions extracted from scrap tyres. The enhancement of the confinement was envisaged through the addition of steel fibers obtained from scrap tyres. The study included an experimental program for the development of constitutive material models for ordinary Portland cement (OPC) concrete and concrete with added steel fibers. A mix design was carried out for OPC, targeting a compressive strength of 3000 psi. Steel fibers were added to OPC in ratios of 1.0% to 3.0%, with an increment of 0.5%. Concrete columns, with cross-sectional dimensions of 6 × 6 inches and a length of 30 inches, were cast with both OPC and fiber-reinforced concrete. The column confinement was evaluated with a different spacing of ties (3- and 4-inch center-to-center). Compression tests on the concrete columns indicate that the addition of steel fibers to a concrete matrix results in an appreciable increase in strength and ductility. Overall, increasing the percentage of steel fibers increased the compression strength and the ductility of concrete. The maximum strain in the concrete containing 2.5% steel fibers increased by 285% as compared to the concrete containing 1% of steel fibers. An optimum percentage of 2.5% steel fibers added to the concrete resulted in a 39% increase in compressive strength, accompanied by a significant improvement in ductility. The optimum content of steel fibers, when used in confined columns, showed that confined compression strength increased with the addition of steel fibers. However, it is recommended that additional columns on the basis of the optimum steel fiber content shall be tested to evaluate their effectiveness in reducing the stirrup spacing.  相似文献   
27.
Dolomite is a natural mineral of great industrial importance and used worldwide, thus millions of workers are at risk of occupational exposure. Its toxicity is however, meagerly documented. In the present investigation, a dolomite powder obtained from its milling unit was analyzed by some standard methods namely, optical microscopy, transmission electron microscopy and dynamic light scattering. Results showed that dolomite powder contained particles of different shapes and size both microparticles (MPs) and nanoparticles (NPs), suggesting potential occupational exposure of these particles. An attempt was therefore, made to investigate dolomite toxicity in a particle size-dependent manner in human lung epithelial cells A(549). The comparative toxicity evaluation of MPs and NPs was carried out by assessing their effects on cell viability, membrane damage, glutathione, reactive oxygen species (ROS), lipid peroxidation (LPO), micronucleus (MN) and proinflammatory cytokines, namely tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). These markers of cytotoxicity, genotoxicity and inflammation were assayed in cells exposed to MPs and NPs in a dose-and time-dependent manner. Invariably, their toxic effects were dose-and time-dependent while NPs in general were significantly more toxic. Notably, NPs caused oxidative stress, genotoxicity and inflammatory responses, as seen by significant induction of ROS, LPO, MN, TNF-α, IL-1β and IL-6. Thus, the study tends to suggest that separate health safety standards would be required for micrometer and nanometer scale particles of dolomite.  相似文献   
28.
29.
Background In Qatar, home diagnostic tests are available over the counter in community pharmacies. While possibly beneficial, these tests have the potential for harm if they are used in the absence of pharmacist counseling. Objectives To determine the public views, level of awareness and use of home diagnostic tests and to evaluate the extent of community pharmacists?? involvement in educating the public about these tests in Qatar. Setting Qatar??s Supreme Council of Health lists 245 community pharmacies in Qatar. Ten community pharmacies were randomly selected from the list as study sites. Method The investigators visited selected pharmacies on different weekdays and at different times of the day. Members of the public who appeared to be over 16?years of age and able to communicate in English or Arabic were randomly approached, provided with the study objectives, and requested to participate. Those who offered oral consent were anonymously interviewed using a multipart survey. Main outcome measures Measures include the public awareness and use of home diagnostic tests and the extent of community pharmacist involvement in educating the public about these tests. Results During the 5-month study period, 297 patients answered the survey (60?% response rate). Most respondents were aware of at least one home diagnostic test (98?%). The top four home diagnostic tests that the respondents had ever heard of included: thermometers (91?%), blood pressure monitors (91?%), blood sugar tests (86?%) and regular pregnancy tests (72?%). Seventy-one percent of respondents had performed at least one home diagnostic test. When asked about the factors that influenced their choice of the home diagnostic tests, the pharmacist was only cited by 7?% of respondents. The majority of respondents (>80?%) agreed that using a home diagnostic test is convenient, comfortable and helps them in early diagnosis and treatment of healthcare conditions. Only 31?% agreed that the pharmacist offered sufficient information on what to do in case the test result turns to be positive. The study results suggest that generally, the public has good attitudes and awareness of home diagnostic tests. However, the results indicate that Qatar community pharmacists are not sufficiently involved in public education about home diagnostic tests. Pharmacists should take a more active role in counseling the public on the proper use of these tests.  相似文献   
30.
Vascular endothelial growth factor (VEGF) is a potent angiogenesis mediator. Scant reports are available defining the role of VEGF in active and inactive tubercular meningitis (TBM) with no studies on brain tuberculoma. We quantified VEGF levels by enzyme linked immunoassay (ELISA) in cerebrospinal fluid (CSF) and serum in 20 cases each with active and inactive TBM as well as 22 cases of intraparenchymal tuberculoma. VEGF expression and microvessel angiogenesis quantification was done in 7 cases where tuberculomas were excised. Significantly increased VEGF levels in CSF were found in active TBM cases (106.0+/-50.0 pg/ml) compared to inactive TBM cases (14.7+/-10.0 pg/ml) (p<0.001). Mean serum VEGF levels in active TBM, inactive TBM and tuberculoma were 694.93+/-820.66 pg/ml, 499.61+/-238.33 pg/ml and 541.0+/-389.0 pg/ml, respectively. Immunohistochemical staining of excised tuberculoma demonstrated high expression of VEGF in granulomatous areas with intense positivity in inflammatory mononuclear cells, Langhan's giant cells as well as reactive astrocytes and fibrocytes. A strong positive correlation was observed between microvessel density and VEGF expression. Serial decrease in serum VEGF levels was observed with increasing duration of therapy in tuberculoma. We conclude that increased CSF and serum VEGF levels are a measure of activity of the disease in neurotuberculosis and its gradual decrease over a period of time is probably an indicator of therapeutic response.  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