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   23201篇
  免费   528篇
  国内免费   567篇
耳鼻咽喉   609篇
儿科学   1255篇
妇产科学   420篇
基础医学   2153篇
口腔科学   1035篇
临床医学   1553篇
内科学   5047篇
皮肤病学   378篇
神经病学   1542篇
特种医学   605篇
外科学   3695篇
综合类   765篇
一般理论   10篇
预防医学   2319篇
眼科学   530篇
药学   1517篇
  4篇
中国医学   339篇
肿瘤学   520篇
  2024年   36篇
  2023年   88篇
  2022年   126篇
  2021年   174篇
  2020年   161篇
  2019年   162篇
  2018年   186篇
  2017年   101篇
  2016年   183篇
  2015年   134篇
  2014年   222篇
  2013年   147篇
  2012年   2102篇
  2011年   2405篇
  2010年   656篇
  2009年   361篇
  2008年   1877篇
  2007年   2127篇
  2006年   1861篇
  2005年   2017篇
  2004年   1912篇
  2003年   1765篇
  2002年   1645篇
  2001年   1127篇
  2000年   1629篇
  1999年   753篇
  1998年   117篇
  1997年   36篇
  1996年   38篇
  1995年   31篇
  1994年   24篇
  1993年   19篇
  1992年   13篇
  1991年   14篇
  1990年   12篇
  1989年   9篇
  1988年   8篇
  1987年   3篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1978年   1篇
  1976年   1篇
  1967年   1篇
  1966年   1篇
  1965年   1篇
  1957年   1篇
  1942年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
刘晓峰  高伟  胡敏 《临床军医杂志》2022,(6):649-650+652
目的 探讨个体化肺康复对慢性阻塞性肺病急性加重期(AECOPD)患者早期康复治疗效果的影响。方法 选取海军971医院2021年1—12月收治的60例AECOPD患者为研究对象。采用随机数字表法将其分为A组与B组,每组各30例。A组患者行常规治疗,B组患者行常规治疗联合个体化肺康复治疗。分别于治疗前、治疗后8周,记录并比较两组患者肺功能指标与慢性阻塞性肺疾病评估测量问卷(CAT)评分。结果 治疗前,两组患者第1秒用力呼气容积(FEV1)、用力呼气量(FVC)、FEV1/FVC与CAT评分比较,差异均无统计学意义(P> 0.05)。治疗后8周,两组患者的FEV1、FVC、FEV1/FVC与CAT评分均优于治疗前,且B组均明显优于A组,差异均有统计学意义(P<0.05)。结论 常规内科治疗联合个体化肺康复治疗AECOPD患者安全可行,且可以明显改善患者的肺功能及生活质量。  相似文献   
72.
Valproic acid (VPA) has been used as an anticonvulsant for the treatment of epilepsy. The authors present a fatal case involving a 45-year-old female, found dead lying in bed with empty tablets of Diplexil® next to her. She was a chronic alcoholic and epileptic who had been under psychiatric treatment, having repeatedly demonstrated intent to commit suicide.A rapid method was developed and validated to determine VPA in blood by ultra-performance liquid chromatography (UPLC) coupled with tandem mass spectrometry (MS/MS) with electrospray ionization source in negative ion mode.The method involved sample treatment with phosphoric acid followed by solid-phase extraction. Chromatographic separation was achieved using an Acquity UPLC® BEH (2.1 × 50 mm id, 1.7 μm) column and a mobile phase containing ammonium acetate and acetonitrile, at a 0.5 mL/min flow rate. Detection and quantification of VPA was achieved using multiple reaction monitoring (MRM). The MS/MS transitions used for monitoring were m/z 143.1–143.1 for valproic acid and m/z 296.1–205.0 for hydrochlorothiazide used as an internal standard (IS).The limit of quantification (LOQ) was 0.5 μg/mL and the method was linear in the concentration range of 0.5–100 μg/mL. The coefficients of variation obtained for accuracy and precision were less than 10% and the mean recovery was 95% for the three concentrations levels studied (5 μg/mL, 10 μg/mL and 50 μg/mL). Toxicological results showed high concentration of VPA (556 μg/mL) and therapeutic concentrations of tiapride, mirtazapine, oxazepam and nordiazepam. Blood sample analysis also revealed the presence of ethanol at a concentration of 1.34 g/L.A specific, selective and sensitive method for the determination of VPA in blood was developed and can be used in routine forensic investigation. Toxicological results led the pathologist to rule that death was due to an intoxication caused by the simultaneous ingestion of high VPA concentrations and alcohol, with a suicidal legal-medical etiology.  相似文献   
73.

BACKGROUND AND PURPOSE

Current data suggest that parathyroid hormone (PTH)-related peptide (PTHrP) domains other than the N-terminal PTH-like domain contribute to its role as an endogenous bone anabolic factor. PTHrP-107-139 inhibits bone resorption, a fact which has precluded an unequivocal demonstration of its possible anabolic action in vivo. We thus sought to characterize the osteogenic effects of this peptide using a mouse model of diabetic low-turnover osteopaenia.

EXPERIMENTAL APPROACH

PTHrP-107-139 was administered to streptozotocin-induced diabetic mice, with or without bone marrow ablation, for 13 days. Osteopaenia was confirmed by dual-energy X-ray absorptiometry and microcomputed tomography analysis. Histological analysis was performed on paraffin-embedded bone tissue sections by haematoxylin/eosin and Masson''s staining, and tartrate-resistent acid phosphatase immunohistochemistry. Mouse bone marrow stromal cells and osteoblastic MC3T3-E1 cells were cultured in normal and/or high glucose (HG) medium. Osteogenic and adipogenic markers were assessed by real-time PCR, and PTHrP and the PTH1 receptor protein expression by Western blot analysis.

KEY RESULTS

PTHrP-107-139 reversed the alterations in bone structure and osteoblast function, and also promoted bone healing after marrow ablation without affecting the number of osteoclast-like cells in diabetic mice. This peptide also reversed the high-glucose-induced changes in osteogenic differentiation in both bone marrow stromal cells and the more differentiated MC3T3-E1 cells.

CONCLUSIONS AND IMPLICATIONS

These findings demonstrate that PTHrP-107-139 promotes bone formation in diabetic mice. This mouse model and in vitro cell cultures allowed us to identify various anabolic effects of this peptide in this scenario.  相似文献   
74.
Resistance to extended-spectrum cephalosporins within members of the family Enterobacteriaceae occurs virtually world-wide. Nevertheless, nothing was known about this problem among isolates from Mexico. To address this issue, we studied oximino-cephalosporin resistant isolates of Klebsiella pneumoniae (13), Escherichia coli (7), and Enterobacter cloacae (23) recovered from patients in Mexico City hospitals during 1990 to 1992. In the presence of clavulanic acid, these strains increased susceptibility to cefotaxime and ceftazidime (MIC90 64 and >256 microg/ml, respectively). The ability of these isolates to transfer resistance to both antibiotics by conjugation was most successfully demonstrated by K. pneumoniae. In all the clinical isolates tested, the largest plasmid coded for the extended-spectrum beta-lactamases (ESBL). Characteristics of pI, by isoelectric focusing (IEF)/bioassay and DNA hybridization with specific probes of TEM and SHV, indicated that in most of the clinical isolates and all transconjugates, the most frequent beta-lactamase coded were SHV-derived (20 strains as 41% of isolates) and a plasmid-encoded beta-lactamase (12 strains as 25% of isolates) (with a pI of >8.2), which is not related to TEM/SHV. Apparently, isolates from Mexico show characteristics similar to isolates from other geographic areas. The type of beta-lactamases coded in these resistant isolates is documented for the first time in Mexico.  相似文献   
75.
BACKGROUND: Early detection of bone metastases in prostatic carcinoma is very useful in treatment and prognosis of the disease. The aim of this work was to evaluate the sensitivity and specificity of a group of bone markers in order to discriminate between prostate carcinoma patients without (M(0)) and with (M(1)) bone metastases. METHODS: Sixty-seven non-treated patients with: benign prostate hyperplasia (n=21), prostatic carcinoma in several stages without bone metastases (T(X)M(0)) (n=31) and with bone metastases (T(X)M(1)) (n=15) were studied. The following markers were studied: (A) bone formation: (1) serum bone alkaline phosphatase, IRMA (Tandem Ostase, Beckman); (2) serum procollagen I amino-terminal propeptide (PINP), RIA (Orion Diagnostica); (B) bone resorption: (1) urinary collagen I amino-terminal telopeptide (NTX), ELISA (Ostex); (2) collagen I carboxy terminal telopeptide (CTX): (2A) urinary alpha-CTX, RIA (Osteometer), (2B) serum beta-CTX, Elecsys (Roche); (3) collagen I cross-linked carboxy terminal telopeptide (ICTP), RIA (Orion Diagnostica). RESULTS: Levels of all bone markers were significantly higher in group M(1) than in group M(0). A complete separation of groups M(0) and M(1) was achieved with PINP and beta-CTX (100% sensitivity and specificity). CONCLUSIONS: These results support the use of PINP or beta-CTX as a tool to confirm the presence or absence of bone metastases in the first staging of prostatic carcinoma patients.  相似文献   
76.
This 54-year-old patient with a breast carcinoma of one year's evolution presented a progressive paraparesis and sphincter disregulation of a week evolution; MRI image showed a tumor in the medullary conus. She improved after removal of the conus mass. The histologic diagnosis was metastasis of adenocarcinoma. Metastasis at this level is infrequent and represents less than 1% of all spinal metastases. When the patients' general condition is good, surgery can relieve the neurologic deficit produced by the medullary mass.  相似文献   
77.
High-performance size-exclusion chromatography (SEC) based on UV-Vis detection is a relative technique for molecular weight determination whereas procedure based on multi-angle laser light scattering (MALLS) is both rapid and absolute. The two methods using recombinant human growth hormone (rHGH) and β-lactoglobulin samples were compared. A calibration curve for the chromatographic system was generated based on standard proteins and the data were fitted by least squares to a third order polynomial model. The molecular weight from the conventional SEC method for both proteins was higher than the reported values. The molecular weight of rHGH from MALLS was 23.1±0.57 and 21.2±0.80 kDa using differential refractive index (SEC-MALLS/RI) and UV (SEC-MALLS/UV-Vis) detectors as mass detectors. Both values agree, within experimental error with the molecular weight sequence of rHGH, 22.1 kDa. In contrast, the molecular weight from LS for β-lactoglobulin was 22.5±0.55 kDa by SEC-MALLS/RI and 23.0±1.22 kDa by SEC-MALLS/UV-Vis, respectively, values always higher than those supplied by the manufacturer, 18.4 kDa. The reproducibilty of the SEC-MALLS/UV-Vis method versus the SEC-MALLS/RI method was performed using the concordance correlation coefficient. The method′s reproducibility was accepted by assuming a precision of 98% and a 1% loss in precision.  相似文献   
78.
Arthroscopic surgery has been reported to decrease pain in relation to the TMJ, improving maximal interincisal opening (MIO). The aim of the present study was to report the clinical outcome of arthroscopic surgery for the treatment of chronic closed lock (CCL) of the TMJ. Five hundred consecutive patients (670 joints) with TMJ derangement who underwent arthroscopy between 1995 and 2004 were retrospectively analysed. All were classified as II-V according to Wilkes. Within the series, various arthroscopic procedures were performed. The inclusion criteria for CCL of the TMJ were met by 257 patients (344 joints). The mean age was 30.24 years; 237 (92%) were female and 20 (8%) male. Mean preoperative visual analogue scale score for evaluation of TMJ pain was 53.21+/-23.02. Mean MIO was 24.75+/-4.89 mm. Following arthroscopy, a significant decrease in TMJ pain was achieved (p<0.0001). For MIO, mandibular protrusion and lateral excursion movements, a significant increase in mean values was observed following surgery (p<0.0001). No statistical differences were observed between arthroscopic lysis and lavage and operative arthroscopy in relation to postoperative pain or MIO at any stage of the follow-up period. Arthroscopy should be considered as a first-line treatment for CCL of the TMJ.  相似文献   
79.
目的 探讨舒适护理在骨科全麻患者术后麻醉恢复室复苏期的应用效果。方法 126例骨科全麻手术患者随机分为两组,对照组行常规护理,舒适护理组在常规护理基础上行舒适护理,比较两组的舒适度、不良护理事件。结果 舒适护理组的生理、环境、心理精神、社会文化舒适度评分均显著高于对照组(P <0.05)。舒适护理组的不良护理事件总发生率为4.76%,显著低于对照组的17.46%(P <0.05)。结论 舒适护理可提高骨科全麻手术患者麻醉恢复室复苏期舒适度,减少不良护理事件的发生。  相似文献   
80.
本文报道小剂量碳酸锂对自发的遗传性糖尿病模型中国地鼠(NIDDM)三个月处理疗效观察。采用胰岛素敏感性指数——空腹血浆胰岛素与血糖乘积的倒数,判断药物疗效。结果显示:碳酸锂使糖尿病鼠血糖降低,血胰岛素无变化,胰岛素敏感性增强。  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