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   8613篇
  免费   485篇
  国内免费   15篇
耳鼻咽喉   44篇
儿科学   288篇
妇产科学   224篇
基础医学   1042篇
口腔科学   56篇
临床医学   1580篇
内科学   1361篇
皮肤病学   96篇
神经病学   898篇
特种医学   130篇
外科学   683篇
综合类   80篇
一般理论   9篇
预防医学   1283篇
眼科学   103篇
药学   650篇
中国医学   7篇
肿瘤学   579篇
  2024年   7篇
  2023年   30篇
  2022年   80篇
  2021年   165篇
  2020年   90篇
  2019年   177篇
  2018年   173篇
  2017年   147篇
  2016年   169篇
  2015年   202篇
  2014年   305篇
  2013年   469篇
  2012年   666篇
  2011年   670篇
  2010年   363篇
  2009年   340篇
  2008年   610篇
  2007年   601篇
  2006年   617篇
  2005年   610篇
  2004年   596篇
  2003年   585篇
  2002年   499篇
  2001年   61篇
  2000年   37篇
  1999年   74篇
  1998年   98篇
  1997年   69篇
  1996年   72篇
  1995年   71篇
  1994年   44篇
  1993年   47篇
  1992年   26篇
  1991年   32篇
  1990年   20篇
  1989年   24篇
  1988年   32篇
  1987年   15篇
  1986年   11篇
  1985年   25篇
  1984年   25篇
  1983年   18篇
  1982年   27篇
  1981年   23篇
  1980年   22篇
  1979年   12篇
  1978年   18篇
  1977年   10篇
  1975年   6篇
  1974年   11篇
排序方式: 共有9113条查询结果,搜索用时 15 毫秒
101.
PURPOSE: Human reovirus type 3 has been proposed to kill cancer cells with an activated Ras signaling pathway. The purpose of this study was to investigate the efficacy of reovirus in immunocompetent glioma animal models and safety/toxicity in immunocompetent animals, including nonhuman primates. EXPERIMENTAL DESIGN: Racine glioma cells 9L and RG2 were implanted s.c. or intracranially in Fisher 344 rats with or without reovirus antibodies, followed by treatment of reovirus. To study whether reovirus kills contralateral tumors in the brain and to determine viral distribution, we established an in situ dual tumor model followed by reovirus intratumoral inoculation only into the ipsilateral tumor. To evaluate neurotoxicity/safety of reovirus, Cynomolgus monkeys and immunocompetent rats were given intracranially with reovirus, and pathological examination and/or behavioral studies were done. Viral shedding and clinical biochemistry were systematically studied in monkeys. RESULTS: Intratumorally given reovirus significantly suppressed the growth of both s.c. and intracranially tumors and significantly prolonged survival. The presence of reovirus-neutralizing antibodies did not abort the reovirus' antitumor effect. Reovirus inhibited glioma growth intracranially in the ipsilateral but not the contralateral tumors; viral load in ipsilateral tumors was 15 to 330-fold higher than the contralateral tumors. No encephalitis or behavioral abnormalities were found in monkeys and rats given reovirus intracranially. No treatment-related clinical biochemistry changes or diffuse histopathological abnormality were found in monkeys inoculated intracranially with Good Manufacturing Practice prepared reovirus. Microscopic changes were confined to the region of viral inoculation and were dose related, suggesting reovirus intracranially was well tolerated in nonhuman primates. CONCLUSIONS: These data show the efficacy and safety of reovirus when it is used in the treatment of gliomas in immunocompetent hosts. Inoculation of reovirus into the brain of nonhuman primates did not produce significant toxicities.  相似文献   
102.
PURPOSE: The purpose of this study was to establish the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and preliminary activity of BMS-188797 administered weekly. EXPERIMENTAL DESIGN: Patients with advanced malignancies were treated with escalating doses of BMS-188797 on a weekly schedule as a 1-h i.v. infusion. Plasma sampling was performed to characterize the pharmacokinetics of BMS-188797. RESULTS: Eighteen patients with advanced malignancies were enrolled at three dose levels ranging from 35 to 65 mg/m(2). The number of patients evaluated at each dose level was as follows: 35 mg/m(2) (n = 3); 50 mg/m(2) (n = 9); and 65 mg/m(2) (n = 6). At 65 mg/m(2), three of six patients had a DLT (one had grade 4 neutropenia lasting >7 days, and two had grade 3 diarrhea). Expansion of the 50-mg/m(2) dose cohort to nine patients established this dose as the MTD, with one patient experiencing a DLT (grade 4 neutropenia with fever). Two partial responses were observed (lung cancer, 7+ months; ovarian cancer, 6+ months durations), as well as two minor responses (esophageal cancer, 5 months; ovarian cancer, 5 months). Both patients with partial responses had been clinically resistant to paclitaxel. Plasma pharmacokinetic mean values of maximum concentration (C(max)) and area under the curve (AUC(0-48)) increased in a dose-dependent manner within the range of doses used in this study, and in three of four patients, the DLTs correlated with AUC. CONCLUSIONS: The MTD and the recommended Phase II dose of weekly BMS-188797 is 50 mg/m(2). The drug demonstrates antitumor activity in taxane-refractory solid tumors and is now being evaluated in combination with carboplatin.  相似文献   
103.
104.
GABA(A) receptors are involved in the subjective effects of alcohol. Endogenous neuroactive steroids interact with GABA(A) receptors to mediate several behavioral effects of alcohol in rodents. Based on a haplotypic association of alcohol dependence with the gene encoding the GABA(A) receptor alpha-2 subunit (GABRA2), we examined whether GABRA2 alleles are associated with the subjective response to alcohol. We also examined whether finasteride (a 5-alpha steroid reductase inhibitor), which blocks the synthesis of some neuroactive steroids, reduces the subjective response to alcohol. In all, 27 healthy social drinkers (15 males) completed a randomized, double-blind, placebo-controlled study of high-dose finasteride. After being pretreated with study drug, subjects consumed three alcoholic drinks. Subjective effects were measured repeatedly over the ascending blood alcohol curve. To examine the moderating role of genetic variation in GABRA2, a single-nucleotide polymorphism that was informative in association studies was included as a factor in the analysis. Subjects homozygous for the more common A-allele (n=7) showed more subjective effects of alcohol than did individuals with one or two copies of the alcohol dependence-associated G-allele (n=20, including two homozygotes). Among the A-allele homozygotes, there was a greater reduction in several subjective effects during the finasteride session compared to the placebo session. These findings provide preliminary evidence that the risk of alcoholism associated with GABRA2 alleles may be related to differences in the subjective response to alcohol. The effects of finasteride provide indirect evidence for a mediating role of neuroactive steroids in some of the subjective effects of alcohol.  相似文献   
105.
PURPOSE: To investigate the gefitinib, fluorouracil (FU), leucovorin, and oxaliplatin regimen (IFOX) in previously treated patients with metastatic colorectal cancer. PATIENTS AND METHODS: Eligible patients had stage IV colorectal adenocarcinoma and had demonstrated progression or intolerance to a prior chemotherapy regimen not including oxaliplatin. Each cycle consisted of 14 days. Cycle 1 consisted of oxaliplatin 85 mg/m2 intravenously (IV) during 2 hours on day 1, hours 0 to 2; leucovorin 200 mg/m2 IV on days 1 and 2, hours 0 to 2; FU 400 mg/m2 IV push on days 1 and 2; and FU 600 mg/m2 IV on days 1 and 2, hours 2 to 24 (FOLFOX-4). All subsequent cycles consisted of FOLFOX-4 with gefitinib at 500 mg/d administered orally throughout the 14-day cycle. RESULTS: Twenty-seven patients were enrolled onto the study. The median number of prior chemotherapy regimens was two, and 74% of all patients received prior irinotecan. Nine of the 27 patients (33%) and six of the 20 patients (30%) who had prior FU and irinotecan had a partial response by Response Evaluation Criteria in Solid Tumors Group criteria. Median overall survival was 12.0 months. Median event-free survival was 5.4 months. Grade 3 to 4 toxicities included neutropenia (48%), diarrhea (48%), nausea (22%), and vomiting (15%). CONCLUSION: IFOX is an active regimen in patients with previously treated metastatic colorectal adenocarcinoma, demonstrating higher response rates than those reported with FOLFOX-4 alone in a similar patient population.  相似文献   
106.
PURPOSE: To develop a guideline for the use of sentinel node biopsy (SNB) in early stage breast cancer. METHODS: An American Society of Clinical Oncology (ASCO) Expert Panel conducted a systematic review of the literature available through February 2004 on the use of SNB in early-stage breast cancer. The panel developed a guideline for clinicians and patients regarding the appropriate use of a sentinel lymph node identification and sampling procedure from hereon referred to as SNB. The guideline was reviewed by selected experts in the field and the ASCO Health Services Committee and was approved by the ASCO Board of Directors. RESULTS: The literature review identified one published prospective randomized controlled trial in which SNB was compared with axillary lymph node dissection (ALND), four limited meta-analyses, and 69 published single-institution and multicenter trials in which the test performance of SNB was evaluated with respect to the results of ALND (completion axillary dissection). There are currently no data on the effect of SLN biopsy on long-term survival of patients with breast cancer. However, a review of the available evidence demonstrates that, when performed by experienced clinicians, SNB appears to be a safe and acceptably accurate method for identifying early-stage breast cancer without involvement of the axillary lymph nodes. CONCLUSION: SNB is an appropriate initial alternative to routine staging ALND for patients with early-stage breast cancer with clinically negative axillary nodes. Completion ALND remains standard treatment for patients with axillary metastases identified on SNB. Appropriately identified patients with negative results of SNB, when done under the direction of an experienced surgeon, need not have completion ALND. Isolated cancer cells detected by pathologic examination of the SLN with use of specialized techniques are currently of unknown clinical significance. Although such specialized techniques are often used, they are not a required part of SLN evaluation for breast cancer at this time. Data suggest that SNB is associated with less morbidity than ALND, but the comparative effects of these two approaches on tumor recurrence or patient survival are unknown.  相似文献   
107.
An uncontrolled study with process evaluation was conducted in three U.K. community maternity sites to establish the feasibility and acceptability of delivering a novel breastfeeding peer‐support intervention informed by motivational interviewing (MI; Mam‐Kind). Peer‐supporters were trained to deliver the Mam‐Kind intervention that provided intensive one‐to‐one peer‐support, including (a) antenatal contact, (b) face‐to‐face contact within 48 hr of birth, (c) proactive (peer‐supporter led) alternate day contact for 2 weeks after birth, and (d) mother‐led contact for a further 6 weeks. Peer‐supporters completed structured diaries and audio‐recorded face‐to‐face sessions with mothers. Semistructured interviews were conducted with a purposive sample of mothers, health professionals, and all peer‐supporters. Interview data were analysed thematically to assess intervention acceptability. Audio‐recorded peer‐support sessions were assessed for intervention fidelity and the use of MI techniques, using the MITI 4.2 tool. Eight peer‐supporters delivered the Mam‐Kind intervention to 70 mothers in three National Health Service maternity services. Qualitative interviews with mothers (n = 28), peer‐supporters (n = 8), and health professionals (n = 12) indicated that the intervention was acceptable, and health professionals felt it could be integrated with existing services. There was high fidelity to intervention content; 93% of intervention objectives were met during sessions. However, peer‐supporters reported difficulties in adapting from an expert‐by‐experience role to a collaborative role. We have established the feasibility and acceptability of providing breastfeeding peer‐support using a MI‐informed approach. Refinement of the intervention is needed to further develop peer‐supporters' skills in providing mother‐centred support. The refined intervention should be tested for effectiveness in a randomised controlled trial.  相似文献   
108.
Single and double dichotic digit tests in Malay language were developed and standardized as an initial attempt to incorporate tests of auditory processing within the scope of audiology practice in Malaysia. Normative data under free recall, directed right-ear first, and directed left-ear first listening conditions were determined using 120 Malay children between the ages of 6 and 11 years old with normal hearing and normal academic performance. Test-retest reliability was assessed in 15 of the study subjects. In general, the double dichotic digit test produced greater differences in scores between age groups, and a greater right-ear advantage than the single dichotic digit test. In addition, the double dichotic digit test also had higher test-retest reliability. These findings suggest the double dichotic digit test is more clinically applicable.  相似文献   
109.
110.
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