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   896篇
  免费   55篇
  国内免费   1篇
耳鼻咽喉   3篇
儿科学   35篇
妇产科学   25篇
基础医学   106篇
口腔科学   11篇
临床医学   83篇
内科学   120篇
皮肤病学   8篇
神经病学   60篇
特种医学   26篇
外科学   66篇
综合类   56篇
一般理论   5篇
预防医学   92篇
眼科学   10篇
药学   181篇
中国医学   20篇
肿瘤学   45篇
  2023年   8篇
  2022年   17篇
  2021年   34篇
  2020年   25篇
  2019年   24篇
  2018年   28篇
  2017年   22篇
  2016年   24篇
  2015年   22篇
  2014年   33篇
  2013年   55篇
  2012年   91篇
  2011年   68篇
  2010年   38篇
  2009年   27篇
  2008年   53篇
  2007年   69篇
  2006年   49篇
  2005年   40篇
  2004年   47篇
  2003年   36篇
  2002年   26篇
  2001年   16篇
  2000年   17篇
  1999年   6篇
  1998年   8篇
  1997年   7篇
  1996年   5篇
  1995年   7篇
  1994年   1篇
  1992年   11篇
  1991年   4篇
  1990年   6篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   4篇
  1984年   1篇
  1977年   1篇
  1974年   9篇
  1973年   4篇
  1972年   2篇
  1970年   1篇
  1966年   1篇
  1964年   1篇
排序方式: 共有952条查询结果,搜索用时 15 毫秒
11.
Exclusive breastfeeding (EBF) for the first 6 months has established benefits, yet had slow improvements globally. Little is known about electronic job aid‐assisted counselling to support EBF. As a secondary outcome of a cluster randomized controlled trial in Bangladesh, we assessed the effect of electronic job aid‐supported nutrition counselling and practical demonstration on EBF. We randomized pregnant women to one of five study arms in the trial and followed mother–child dyads until 2 years of age. Community health workers (CHWs) provided breastfeeding counselling with or without prenatal and complementary nutrient supplements in all four intervention arms. The comparison arm continued with the usual practice where mothers could receive nutrition counselling at routine antenatal and postnatal care, and during careseeking for childhood illnesses. We assessed breastfeeding indicators at birth and monthly until the child was 6 months old, in both intervention and comparison arms. To evaluate the effect of nutrition counselling on breastfeeding, we combined all four intervention arms and compared them with the comparison arm. Intervention newborns had half the risk (relative risk [RR]: 0.54, 95% confidence interval [CI]: 0.39, 0.76) of receiving prelacteal feeds than those in the comparison arm. EBF declined steeply in the comparison arm after 3 months of age. EBF was 16% higher in the intervention than the comparison arm at 4 months (RR: 1.16, 95% CI: 1.08, 1.23) and 22% higher at 5 months of age (RR: 1.22, 95% CI: 1.12, 1.33). Maternal background and household characteristics did not modify the intervention effect, and we observed no difference in EBF among caesarean versus vaginal births. Breastfeeding counselling and practical demonstration using an electronic job aid by CHWs are promising interventions to improve EBF and are scalable into existing community‐based programmes.  相似文献   
12.
Post-kala-azar dermal leishmaniasis (PKDL) is a complication of visceral leishmaniasis (VL) and serves as a potential reservoir for Leishmania parasite. The study was aimed to evaluate the spectrum of skin lesions of PKDL in kala-azar endemic areas in Bangladesh. This cross sectional study was carried out to observe the characteristics of skin lesions among 250 PKDL cases. The suspected PKDL patients in highly endemic villages of Fulbaria Upazilla of Mymensingh district.were subjected to a dipstick test (rK39) for kala azar. The median time interval between diagnosing kala-azar and PKDL was 23 month (m-21, r- 0-60 months). The most common skin lesions were multiple symmetrical hypopigmented macules with irregular margins in 179(71.6%) cases followed by erythematous facial induration in 74(29.6%), papular in 33(13.2%), nodular in 28(11.2%) cases, combination of macules, papules, nodules and plaques in 88(35.2%) cases, annular in 7(2.8%) cases and Papillomatous mucosal growth in 2(0.8%) cases. Sites of involvement were mostly in face (92.4%), Trunk (84.8%), extremities (33.2%), oral mucosa and tongue (0.8%) and Genitalia (1.2%). Suspicion of PKDL on the basis of skin lesions will lead to early diagnosis and prompt treatment will impart an important role in prevention and eradication of Leishmaniasis in Bangladesh.  相似文献   
13.
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   
14.
CONTEXT: Genetic aberration in phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been detected in numerous and diverse human cancers. PIK3CA, which encodes for the catalytic subunit of p110alpha of PI3K, is amplified in some cases of papillary thyroid cancer (PTC). Mutations in the PIK3CA have also been identified in thyroid cancers and, although relatively common in anaplastic thyroid carcinoma, are uncommon in PTC. OBJECTIVE: The objective of the study was to investigate genetic alterations like PIK3CA gene mutation, PIK3CA amplification, RAS, and RAF mutations and to further explore the relationship of these genetic alterations with various clinicopathological characteristics in Middle Eastern PTC. DESIGN: We used the fluorescence in situ hybridization technique for analysis of PIK3CA amplification from 536 PTC cases, and selected amplified samples were further validated by real-time quantitative PCR. Mutation analysis was done by direct DNA sequencing of PIK3CA, N2-RAS, and BRAF genes. RESULTS: PIK3CA amplification was seen in 265 of 499 PTC cases analyzed (53.1%); PIK3CA gene mutations in four of 207 PTC (1.9%); N2-RAS mutations in 16 of 265 PTC (6%); and BRAF mutations in 153 of 296 PTC (51.7%). N-RAS mutations were-associated with an early stage (P = 0.0465) and lower incidence of extrathyroidal extension (P = 0.027), whereas BRAF mutations were-associated with metastasis (P = 0.0274) and poor disease-free survival (P = 0.0121) in PTCs. CONCLUSION: A higher incidence of PIK3CA alterations and the possible synergistic effect of PIK3CA alterations and BRAF mutations suggest their major role in Middle Eastern PTC tumorigenesis and argue for therapeutic targeting of PI3K/AKT and MAPK pathways.  相似文献   
15.
Quantitative determination of gatifloxacin in tablets, solid lipid nanoparticles (SLNs) and eye-drops using a very simple and rapid chromatographic technique was validated and developed. Formulations were analyzed using a reverse phase SUPELCO® 516 C-18-DB, 50306-U, HPLC column (250 mm × 4.6 mm, 5 μm) and a mobile phase consisting of disodium hydrogen phosphate buffer:acetonitrile (75:25, v/v) and with orthophosphoric acid pH was adjusted to 3.3 The flow rate was 1.0 mL/min and analyte concentrations were measured using a UV-detector at 293 nm. The analyses were performed at room temperature (25 ± 2 °C). Gatifloxacin was separated in all the formulations within 2.767 min. There were linear calibration curves over a concentration range of 4.0–40 μg.mL−1 and correlation coefficients of 0.9998 with an average recovery above 99.91%. Detection of analyte from different dosage forms at the same Rt indicates the specificity and stability of the developed method.  相似文献   
16.
We report three families with arterial aneurysms and dissections in which variants predicted to be pathogenic were identified in SMAD2. Moreover, one variant occurred de novo in a proband with unaffected parents. SMAD2 is a strong candidate gene for arterial aneurysms and dissections given its role in the TGF‐β signaling pathway. Furthermore, although SMAD2 and SMAD3 probably have functionally distinct roles in cell signaling, they are structurally very similar. Our findings indicate that SMAD2 mutations are associated with arterial aneurysms and dissections and are in accordance with the observation that patients with pathogenic variants in genes encoding proteins involved in the TGF‐β signaling pathway exhibit arterial aneurysms and dissections as key features  相似文献   
17.
18.
19.
Clinical Oral Investigations - Systematic review analyzing the treatment outcomes of cracked teeth that received endodontic treatment is unavailable. The purpose of this study was to examine the...  相似文献   
20.
PurposeThe project piloted a perioperative music listening program to explore the feasibility and acceptability of the use of music in a perioperative setting for female surgical patients in an academic hospital in Singapore. The aim was also to examine the most commonly chosen music genres, timing, and length of time listening to music for perioperative patients to assess the impact of music on patients' satisfaction, anxiety, and depression.DesignThis was a quality improvement project.MethodsMusic playlists developed by a music therapist were installed on three iPod TouchTM devices (Apple, Cupertino, CA). After obtaining consent, female patients undergoing elective gynecologic day surgery selected their preferred music from the playlists on the iPods to listen to during the preoperative and postoperative periods. Patients' anxiety and depression were measured using the Hospital Anxiety and Depression Scale and the three-level version of the EuroQol five-dimensional questionnaire. Patients' satisfaction with listening to music, duration, and chosen music genres were recorded.FindingsIn the project, 135 patients listened to music during the preoperative period, and 70 patients chose to listen to music in the postoperative period. Patients were satisfied with the music listening program in both the preoperative (95.5%) and the postoperative (91.5%) periods. In the preoperative period, the most popular music genres were Disney songs (17.7%), classical music (11.6%), and the Piano Guys (7.5%). In the postoperative period, the most favorable music genres were classical music (26.3%), Disney songs (7.9%), and the Beatles (7.9%). This project suggests that music listening may be associated with patients' decreased anxiety and depression as measured by the three-level version of the EuroQol five-dimensional questionnaire questionnaire (P = .008).ConclusionsImplementation of a music listening program in perioperative settings is feasible and accepted well by patients as evidenced by the high satisfaction scores. The project addressed patients' satisfaction, anxiety, and depression before and after elective surgery. The findings suggest that music listening is a safe, inexpensive, and effective intervention in perioperative settings.  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