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   15670篇
  免费   1683篇
  国内免费   69篇
耳鼻咽喉   211篇
儿科学   529篇
妇产科学   316篇
基础医学   1869篇
口腔科学   1037篇
临床医学   1392篇
内科学   3614篇
皮肤病学   509篇
神经病学   879篇
特种医学   414篇
外国民族医学   4篇
外科学   2409篇
综合类   408篇
一般理论   6篇
预防医学   1127篇
眼科学   336篇
药学   1185篇
中国医学   118篇
肿瘤学   1059篇
  2024年   13篇
  2023年   185篇
  2022年   478篇
  2021年   800篇
  2020年   518篇
  2019年   753篇
  2018年   815篇
  2017年   633篇
  2016年   730篇
  2015年   686篇
  2014年   839篇
  2013年   1037篇
  2012年   1156篇
  2011年   1309篇
  2010年   788篇
  2009年   582篇
  2008年   799篇
  2007年   704篇
  2006年   666篇
  2005年   656篇
  2004年   574篇
  2003年   478篇
  2002年   431篇
  2001年   203篇
  2000年   191篇
  1999年   174篇
  1998年   97篇
  1997年   70篇
  1996年   71篇
  1995年   66篇
  1994年   50篇
  1993年   57篇
  1992年   61篇
  1991年   35篇
  1990年   51篇
  1989年   59篇
  1988年   63篇
  1987年   77篇
  1986年   63篇
  1985年   51篇
  1984年   45篇
  1983年   35篇
  1982年   27篇
  1981年   30篇
  1980年   15篇
  1979年   21篇
  1978年   18篇
  1977年   21篇
  1975年   16篇
  1973年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Aim: Transarterial chemoembolisation (TACE) is recommended therapy for intermediate-stage hepatocellular carcinoma (HCC). However, the wide variations in outcom...  相似文献   
82.
83.
Grapevine red blotch disease emerged within the past decade, disrupting North American vine stock production and vineyard profitability. Our understanding of how grapevine red blotch virus (GRBV), the causal agent of the disease, interacts with its Vitis hosts and insect vector, Spissistilus festinus, is limited. Here, we studied the capabilities of S. festinus to transmit GRBV from and to free-living vines, identified as first-generation hybrids of V. californica and V. vinifera ‘Sauvignon blanc’ (Vcal hybrids), and to and from V. vinifera ‘Cabernet franc’ (Vvin Cf) vines. The transmission rate of GRBV was high from infected Vcal hybrid vines to healthy Vcal hybrid vines (77%, 10 of 13) and from infected Vvin Cf vines to healthy Vcal hybrid vines (100%, 3 of 3). In contrast, the transmission rate of GRBV was low from infected Vcal hybrid vines to healthy Vvin Cf vines (15%, 2 of 13), and from infected Vvin Cf vines to healthy Vvin Cf vines (19%, 5 of 27). No association was found between transmission rates and GRBV titer in donor vines used in transmission assays, but the virus titer was higher in the recipient leaves of Vcal hybrid vines compared with recipient leaves of Vvin Cf vines. The transmission of GRBV from infected Vcal hybrid vines was also determined to be trans-stadial. Altogether, our findings revealed that free-living vines can be a source for the GRBV inoculum that is transmissible by S. festinus to other free-living vines and a wine grape cultivar, illustrating the interconnected roles of the two virus hosts in riparian areas and commercial vineyards, respectively, for virus spread. These new insights into red blotch disease epidemiology will inform the implementation of disease management strategies.  相似文献   
84.
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   
85.
Dietary intervention is generally accepted as the mainstay of treatment for patients with disorders of amino acid metabolism (AAMDs). However, dietary adherence to a low-protein diet is always reported as a common challenge among these patients. This study explored the perception of barriers and motivators to dietary adherence among caregivers of AAMD patients in Malaysia. Twenty caregivers of children with AAMDs receiving ongoing treatment at the genetic clinic participated in an online focus group discussion from November to December 2021. Findings showed a total of five interrelated main themes identified from focus group discussion (FGD) exploring parents’ experiences related to the management of their child’s daily diet. The barriers to dietary adherence were burden of dietary treatment, diet and dietary behavior, parenting challenges, limited knowledge related to dietary treatment, and challenges in healthcare system delivery. Key factors facilitating good dietary adherence include good knowledge of dietary treatment, parental coping strategies, social coping, and dietary behavior. In conclusion, despite the existence of several barriers to the implementation of dietary treatment, caregivers managed to use a wide range of coping strategies to overcome some, if not all, of the challenges. The important next step is to develop, in conjunction with multidisciplinary healthcare professionals, feasible implementation strategies that could address these barriers and at the same time improve the quality of life of caregivers.  相似文献   
86.
The aim of the present study was to evaluate the effect of brushing with two whitening dentifrices (Colgate Optic White (COW) and Colgate Optic White Charcoal (COC)) on surface gloss, micro-roughness, and micro-hardness of nanostructured hybrid conventional (Z350) and bulk-fill (Tetric N Ceram bulk-fill) polymer composite. In total, 96 disk samples using two nano-hybrid composite polymers (Z350 and Tetric N Ceram Bulk-fill) were prepared. All specimens were exposed to two different dentifrices (COW and COC), resulting in four main subgroups in the study. Specimens were assessed for surface gloss, micro-roughness (Ra), and micro-hardness using standardized methodology. Means and standard deviations of properties compared using paired t-test, one-way and two-way ANOVA, and post hoc test. The presence of dentifrices did not show any significant difference in micro-hardness values of Z350 (p > 0.05), whereas micro-hardness of bulk-fill composite significantly reduced on dentifrices exposure (p ≤ 0.05). Bulk-fill polymer composite showed significant reduction in gloss after dentifrice exposure (p < 0.05), however, Z350 showed no significant loss of gloss due to dentifrices (p > 0.05). A significant increase in Ra was observed for both resin materials after exposure to dentifrices (COC and COW). Conventional resin composite (Z350) showed comparable surface hardness and gloss before and after dentifrice exposure, however, micro-roughness increased significantly due to dentifrice exposure. Bulk-fill resin (Tetric N Ceram) showed significant loss of micro-hardness and gloss and increase in micro-roughness on dentifrice exposure. Conventional nano-hybrid composite polymer showed better durability in resisting loss of surface properties compared to bulk-fill resin polymer in the present experiment.  相似文献   
87.
Older individuals are more vulnerable to severe coronavirus disease 2019 and medical complications. Vaccination stands as an efficient and safe vanguard against infection. However, negative attitudes and perceptions pertaining to available vaccines might hinder community inoculation. The aim of this study was to assess vaccine hesitancy and its psychosocial determinants among the elderly in Qatar.We conducted a cross-sectional study between October 15 and November 15, 2020, using a composite online survey including the Vaccine Attitudes Examination Scale in addition to questions on sociodemographic correlates and the role of healthcare professionals.The vaccine hesitancy rate was 19.5%. The main reasons for willingness to vaccinate included understanding the nature of disease and role of vaccination, in addition to information provided by physicians. Fears mainly centered around vaccine safety. Vaccine hesitators were more likely to be non-Qatari and having received the influenza vaccine at least once. Gender, marital status, socioeconomic status, educational level, and having completed childhood vaccinations were not associated with vaccine hesitancy.Efforts should be directed toward raising awareness of vaccine efficacy and safety profiles. Physicians should additionally be educated about their pivotal role in advocating vaccine acceptance. We recommend reassessing vaccine hesitancy and its associated factors following a year of campaigning and vaccine administration to identify and target vulnerable groups.  相似文献   
88.
Rational modification of molecular structure by incorporating electron donating groups can play a potential role for designing aggregation induced emission (AIE) active fluorescent probes. Based on this principle, fluorescent probes (1a–c) were synthesized, and they displayed excellent aggregation induced emission (AIE) behavior in a H2O/DMF (4 : 1, v/v) mixture due to restrictions in intramolecular charge transfer (ICT). As a comparison, probe 1d was synthesized by installing an electron withdrawing (–NO2) group that surprisingly quenched the aggregation behaviour. Additionally, AIE active probes 1a–c displayed a highly sensitive dual channel (fluorometric and colorimetric) response towards rapid detection of CN, which is an active toxic material. Probes 1a–c showed selectively enhanced fluorescence emission behavior towards CN with detection limits of 1.34 ppb, 1.38 ppb, and 1.54 ppb, respectively. The sensing mechanism involves Michael type adduct formation due to the nucleophilic addition reaction of cyanide with probes and was confirmed through 1H NMR titration experiments. In contrast, probe 1d containing an electron withdrawing moiety showed insensitivity towards CN. Therefore, this study provides the efficient strategy to induce AIE character in fluorescent probes and expands the mechanistic approach toward the sensing of toxic CN.

Rational modification of molecular structure by incorporating electron donating groups can play a potential role for designing aggregation induced emission (AIE) active fluorescent probes.  相似文献   
89.
Nor-pseudoephedrine, one of the active ingredients of khat (Catha edulis), was found to be excreted in breast-milk in several lactating women who were chewing the leaves of the shrub according to the local customs. The compound could be traced in the urine of one breast-fed infant. It is concluded that the use of khat during lactation should be discouraged until further research has clearly elucidated the potential health hazards.  相似文献   
90.
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   
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