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   12463篇
  免费   861篇
  国内免费   22篇
耳鼻咽喉   87篇
儿科学   402篇
妇产科学   366篇
基础医学   1525篇
口腔科学   139篇
临床医学   2211篇
内科学   1959篇
皮肤病学   164篇
神经病学   1206篇
特种医学   268篇
外科学   1185篇
综合类   221篇
一般理论   24篇
预防医学   1501篇
眼科学   288篇
药学   818篇
  2篇
中国医学   7篇
肿瘤学   973篇
  2023年   56篇
  2022年   128篇
  2021年   213篇
  2020年   138篇
  2019年   224篇
  2018年   256篇
  2017年   205篇
  2016年   201篇
  2015年   232篇
  2014年   316篇
  2013年   574篇
  2012年   770篇
  2011年   886篇
  2010年   467篇
  2009年   451篇
  2008年   804篇
  2007年   809篇
  2006年   876篇
  2005年   852篇
  2004年   903篇
  2003年   844篇
  2002年   754篇
  2001年   166篇
  2000年   109篇
  1999年   136篇
  1998年   154篇
  1997年   130篇
  1996年   97篇
  1995年   104篇
  1994年   75篇
  1993年   78篇
  1992年   102篇
  1991年   70篇
  1990年   76篇
  1989年   66篇
  1988年   61篇
  1987年   62篇
  1986年   79篇
  1985年   62篇
  1984年   65篇
  1983年   67篇
  1982年   55篇
  1981年   63篇
  1980年   69篇
  1979年   40篇
  1978年   44篇
  1977年   36篇
  1976年   30篇
  1975年   32篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
BackgroundObesity is an important comorbidity affecting outcomes after total joint arthroplasty. Consequently, surgeons may delay care of obese patients to first address obesity through different care pathways. The effect of obesity on patient wait times for total joint arthroplasty has not been explored. The purpose of this study was to evaluate the effect of obesity on access to total hip (THA) and knee (TKA) arthroplasty.MethodsThe study data set was constructed from the Nova Scotia Health Authority’s Horizon Patient Folder system and the Patient Access Registry Nova Scotia. Wait time was measured as days between the decision to treat and date of surgery. Body mass index (BMI) was calculated from a preoperative assessment, and patients were grouped into BMI categories. Multivariate log-linear regression was used to test for statistical differences, controlling for confounding factors.ResultsWe observed longer wait times for TKA with increasing BMI weight class. Patients with BMIs greater than 50 had 34% longer waits than reference weight patients. However, THA recipients showed no statistical difference in wait times across weight categories. Furthermore, there was variability among surgeons in the wait times experienced by patients.ConclusionThe finding of longer wait times for TKAs, but not THAs, among patients who were obese was unexpected. This shows the variable wait times for THA and TKA that patients who are obese can experience with different surgeons. It is important to understand the variability in wait times so that efforts to standardize the patient experience can be accomplished.  相似文献   
62.
63.
BackgroundTezacaftor (TEZ)/ivacaftor (IVA) is an approved CFTR modulator shown to be efficacious and generally safe and well tolerated in people ≥12 years of age with cystic fibrosis (CF) homozygous for the F508del-CFTR mutation or heterozygous for the F508del-CFTR mutation and a residual function mutation. Although previous studies with IVA alone showed clinical benefits in people with CFTR gating mutations, TEZ/IVA has not yet been evaluated in a Phase 3 study of participants heterozygous for F508del-CFTR and a gating mutation (F/gating genotypes). Here, we present results from a randomized, double-blind, IVA-controlled, parallel-group, Phase 3 study assessing the efficacy, safety, and pharmacokinetics (PK) of TEZ/IVA in participants ≥12 years of age with F/gating genotypes.MethodsEnrolled participants entered a 4-week IVA run-in period to create a stable IVA baseline. Participants were then randomized to receive IVA or TEZ/IVA for 8 weeks in an active comparator treatment period (ACTP). The primary endpoint was absolute change in percent predicted forced expiratory volume in 1 second (ppFEV1). Key secondary endpoints were relative change in ppFEV1 and absolute change in CF Questionnaire–Revised respiratory domain score. Secondary endpoints included absolute change in sweat chloride (SwCl) concentration, PK parameters, and safety. All endpoints except PK parameters and safety were assessed from baseline through Week 8.ResultsSixty-nine participants (92.0%) in the IVA group and 75 participants (98.7%) in the TEZ/IVA group completed treatment. No improvements were seen in efficacy endpoints from baseline at the end of the IVA run-in period through the end of the ACTP in the IVA group. No significant differences in ppFEV1 or any key secondary endpoint were observed between the IVA and TEZ/IVA groups. SwCl concentrations decreased more in the TEZ/IVA versus IVA group during the ACTP. The safety profile and PK parameters of TEZ/IVA were consistent with those of previous studies in participants ≥12 years of age with CF.ConclusionsThis Phase 3 study showed that the dual-combination regimen of TEZ/IVA demonstrated clinical efficacy but did not have significantly greater clinical efficacy than IVA alone in participants ≥12 years of age with F/gating genotypes. However, as reported in other studies, TEZ/IVA was generally safe and well tolerated (NCT02412111).  相似文献   
64.
65.
The influence of ethanol on the permeation of 17-estradiol (estradiol) across viable human skin in vivo was investigated with the human skin sandwich flap model. Maintaining continuous delivery of a constant concentration of the solute in phosphate-buffered saline, pH 7.4 (PBS), or mixtures of ethanol in PBS to the skin surface revealed that steady-state flux of estradiol was achieved within 30–60 min and maintained throughout 4 hr. The 10-fold decrease in in vivo flux and permeability coefficient (K p) of tracer estradiol solutions in ethanol or ethanol solutions compared with PBS vehicle reflected the 10-fold difference in the apparent partition coefficients (K m) of estradiol from the respective vehicles into isolated human stratum corneum. Neither the stratum corneum thickness nor the diffusion coefficient of estradiol was significantly different among the vehicles tested. In vivo flux of estradiol in ethanol or ethanol solutions across viable human skin was increased with saturated solutions of estradiol. Further, in vivo flux of estradiol from vehicles such as PBS, ethanol, and ethanol mixtures, which minimally alter the rate-limiting barrier, can be successfully predicted with knowledge of only two physicochemical parameters, the estradiol concentration in the vehicle and the K m of estradiol from the vehicle into isolated human stratum corneum.  相似文献   
66.
The Covid-19 pandemic lockdown regulations caused retirement homes to temporarily ban in-person visitation potentially increasing the mental health risks of older people. An opportunity arose for a multistakeholder community collaboration to design a mental health program for older people. To evaluate the process of delivering a 12-week psychosocial program aimed at preventing loneliness, countering boredom, and providing older people in restricted settings with education about Covid-19 during the lockdown, in Durban, South Africa. A qualitative retrospective design was used. Data from two focus groups and six semistructured individual interviews conducted with stakeholders (volunteers, social workers, and residents) postproject were analyzed using reflexive thematic analysis. Stakeholders had varied experiences of the project, in terms of content, processes of engagement, and implementation, resulting in five themes. The study concluded with recommendations. A strong need exists for multistakeholder community collaborations when implementing a program where the context restricts physical access.  相似文献   
67.
68.
Using prospective data gathered from a sample of 323 college women over a 10-week academic quarter, the present study examined whether dissociation and posttraumatic symptomatology mediate or moderate sexual revictimization. Results indicated that posttraumatic symptomatology, but not dissociation, moderated the link between previous and subsequent sexual victimization. Neither posttraumatic symptomatology nor dissociation mediated revictimization.  相似文献   
69.

Purpose

We evaluated risk factors for the development of bladder tumors in spinal cord injury patients.

Materials and Methods

A retrospective review was done of all bladder tumors at 1 institution with matched controls for 7 years.

Results

We identified 17 malignant and 2 benign tumors. Indwelling bladder catheters and a history of bladder stones were statistically significant risk factors. Four patients with negative biopsies underwent repeat biopsy due to suspicious cytology and cancer was found.

Conclusions

An indwelling urinary catheter and a history of bladder stones are statistically significant risk factors. Cytology and biopsy are complementary in the evaluation of urothelial malignancy in this population. A high index of suspicion and thorough evaluation are needed in spinal cord injury patients.  相似文献   
70.

Purpose

To compare two doses of bolus epidural morphine with bolus iv morphine for postoperative pain after abdominal or genitourinary surgery in infants.

Methods

Eighteen infants were randomly assigned to bolus epidural morphine (0.025 mg · kg?1 or 0.050 mg · kg?1) or bolus iv morphine (0.050–0.150 mg · kg?1). Postoperative pain was assessed and analgesia provided, using a modified infant pain scale. Monitoring included continuous ECG, pulse oximetry, impedance and nasal thermistor pneumography. The CO2 response curves and serum morphine concentrations were measured postoperatively.

Results

Postoperative analgesia was provided within five minutes by all treatment methods. Epidural groups required fewer morphine doses (3.8 ± 0.8 for low dose [LE], 3.5 ± 0.8 for high dose epidural [HE] vs. 6.7 ± 1.6 for iv, P < 0.05) and less total morphine (0.11 ± 0.04 mg · kg?1 for LE, 0.16 ± 0.04 for HE vs 0.67 ± 0.34 for iv, P < 0.05) on POD1 Dose changes were necessary in all groups for satisfactory pain scores. Pruritus, apnoea, and haemoglobin desaturation occurred in all groups. CO2 response curve slopes, similar preoperatively (range 36–41 ml · min?1 · mmHg ETco 2 ?1 · kg?1) were generally depressed (range, 16–27 ml · min?1 · mmHg ETco 2 ?1 · kg?1) on POD1. Serum morphine concentrations, negligible in LE (<2 ng · ml?1), were similar in the HE and iv groups (peak 8.5 ± 12.5 and 8.6 ± 2.4 ng · ml?1, respectively).

Conclusion

Epidural and iv morphine provide infants effective postoperative analgesia, although side effects are common. Epidural morphine gives satisfactory analgesia with fewer doses (less total morphine); epidural morphine 0.025 mg · kg?1 is appropriate initially. Infants receiving epidural or iv morphine analgesia postoperatively need close observation in hospital with continuous pulse oximetry.  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