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   14997篇
  免费   963篇
  国内免费   152篇
耳鼻咽喉   200篇
儿科学   341篇
妇产科学   164篇
基础医学   1845篇
口腔科学   230篇
临床医学   1191篇
内科学   3916篇
皮肤病学   300篇
神经病学   1032篇
特种医学   613篇
外科学   2108篇
综合类   201篇
一般理论   21篇
预防医学   1077篇
眼科学   350篇
药学   909篇
中国医学   61篇
肿瘤学   1553篇
  2024年   14篇
  2023年   97篇
  2022年   199篇
  2021年   343篇
  2020年   236篇
  2019年   332篇
  2018年   373篇
  2017年   352篇
  2016年   394篇
  2015年   439篇
  2014年   553篇
  2013年   691篇
  2012年   1119篇
  2011年   1076篇
  2010年   668篇
  2009年   526篇
  2008年   999篇
  2007年   1104篇
  2006年   980篇
  2005年   1035篇
  2004年   885篇
  2003年   958篇
  2002年   900篇
  2001年   135篇
  2000年   114篇
  1999年   134篇
  1998年   167篇
  1997年   178篇
  1996年   140篇
  1995年   131篇
  1994年   89篇
  1993年   77篇
  1992年   63篇
  1991年   50篇
  1990年   46篇
  1989年   38篇
  1988年   34篇
  1987年   29篇
  1986年   23篇
  1985年   25篇
  1984年   27篇
  1983年   32篇
  1982年   28篇
  1981年   24篇
  1980年   29篇
  1978年   23篇
  1977年   29篇
  1976年   17篇
  1973年   15篇
  1966年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The biologic properties of adenomyosis and the effects of therapeutic agents on adenomyosis were evaluated with immunohistochemistry, terminal deoxy-nucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method, transmission electron microscopy, and analysis of genomic abnormality. In the adenomyotic endometrium, estrogen receptor (ER) expression was more intense than in the eutopic endometrium during the secretory phase, and bcl-2 was constantly expressed throughout the menstrual cycle. The expression of ER and bcl-2 was weaker in the adenomyotic endometrium treated with danazol than in that treated with gonadotro-pin-releasing hormone agonist (GnRHa), whereas bcl-2 phosphorylated on serine-87 was more intensely expressed in danazol-treated adenomyotic endometrium than in the GnRHa-treated one. The number of TUNEL-positive cells increased in the adenomyotic endometrium treated with danazol or GnRHa. Ultrastructurally, most of the adenomyotic endometrial cells treated with danazol underwent postapoptotic necrosis and formed a cluster of dead cells. In contrast, cells treated with GnRHa underwent typical apoptosis and were sparsely distributed in the adenomyotic endometrium. Analysis of several cancer-related genes showed no microsatellite instability or loss of heterozygosity in adenomyotic tissues. Therefore, we conclude that the occurrence of adenomyosis is correlated to bcl-2 expression regulated by estrogen and ER rather than genetic mutation.  相似文献   
82.
83.
A new simply and effective fractionation method for cylindrospermopsin (CYN) analyses was developed. The extract from cells of Cylindrospermopsis raciborskii was resuspended with 0.1 M carbonate buffer at pH 10.5, and pass through the double-cartridges column which was consisted of a styrene polymer cartridge and an anion exchange cartridge. CYN and deoxy-CYN were adsorbed with the anion exchange cartridge. After separation of the anion exchange cartridge, adsorbed compounds were eluted from the cartridge with 50% methanol containing 1% formic acid solution. CYN and deoxy-CYN were selectively condensed in the eluted solution. When CYN was analyzed by LC-photodiode array or LC/MS, only two peaks of CYN and deoxy-CYN were detected quantitatively. The results suggest that the fractionation method is a useful method for CYN analyses and must be utilized for CYN purification.  相似文献   
84.
PURPOSE: Liposomal lurtotecan (OSI-211) is a liposomal formulation of the water-soluble topoisomerase I inhibitor lurtotecan (GI147211), which demonstrated superior levels of activity compared with topotecan in preclinical models. We studied two schedules of OSI-211 in a randomized design in relapsed ovarian cancer to identify the more promising of the two schedules for further study. PATIENTS AND METHODS: Eligible patients had measurable epithelial ovarian, fallopian, or primary peritoneal cancer that was recurrent after one or two prior regimens of chemotherapy. Patients were randomly assigned to receive either arm A (OSI-211 1.8 mg/m(2)/d administered by 30-minute intravenous infusion on days 1, 2, and 3 every 3 weeks) or arm B (OSI-211 2.4 mg/m(2)/d administered by 30-minute intravenous infusion on days 1 and 8 every 3 weeks). The primary outcome measure was objective response, which was confirmed by independent radiologic review, and a pick the winner statistical design was used to identify the schedule most likely to be superior. RESULTS: Eighty-one patients were randomized between October 2000 and September 2001. The hematologic toxic effects were greater on arm A than on arm B (grade 4 neutropenia, 51% v 22%, respectively), as was febrile neutropenia (26% v 2.4%, respectively). Of the 80 eligible patients, eight patients (10%) had objective responses; six responders (15.4%; 95% CI, 6% to 30%) were in arm A and two responders (4.9%; 95% CI, 1% to 17%) were in arm B. CONCLUSION: The OSI-211 daily for 3 days intravenous schedule met the statistical criteria to be declared the winner in terms of objective response. This schedule was also associated with more myelosuppression than the schedule of OSI-211 administered in arm B.  相似文献   
85.
Corrosion of medical implants is a possible failure mode via induced local inflammatory effects, systemic deposition and corrosion related mechanical failure. Cyclic potentiodynamic polarisation (CPP) testing was utilized to evaluate the effect of increased porosity (60% and 80%) and decreased wall thickness in gyroid lattice structures on the electrochemical behaviour of LPBF Ti6Al4V structures. The use of CPP allowed for the landmarks of breakdown potential, resting potential and vertex potential to be analysed, as well as facilitating the construction of Tafel plots and qualitative Goldberg analysis. The results indicated that 60% gyroid samples were most susceptible to the onset of pitting corrosion when compared to 80% gyroid and solid samples. This was shown through decreased breakdown and vertex potentials and were found to correlate to increased lattice surface area to void volume ratio. Tafel plots indicated that despite the earlier onset of pitting corrosion, both gyroid test groups displayed lower rates of corrosion per year, indicating a lower severity of corrosion. This study highlighted inherent tradeoffs between lattice optimisation and corrosion behaviour with a potential parabolic link between void volume, surface area and corrosion being identified. This potential link is supported by 60% gyroid samples having the lowest breakdown potentials, but investigation into other porosity ranges is suggested to support the hypothesis. All 3D printed materials studied here showed breakdown potentials higher than ASTM F2129′s suggestion of 800 mV for evaluation within the physiological environment, indicating that under static conditions pitting and crevice corrosion should not initiate within the body.  相似文献   
86.
英利昔单抗在消化系统疾病中的应用状况及前景   总被引:3,自引:0,他引:3  
目的:评价英利昔单抗在消化系统相关疾病治疗中的疗效和安全性。方法:收集国外相关文献进行综述、分析。结果及结论:英利昔单抗作为新一代的抗炎药通过中和TNF-α的生物学效应而发挥抗炎作用。对于克罗恩病、溃疡性结肠炎、酒精性肝病等消化系统疾病都有较好疗效,且在推荐的治疗范围内安全性良好。  相似文献   
87.
OBJECTIVES: To estimate the long-term impact of treatment with perindopril on costs and health effects in patients with stable coronary artery disease in Poland. METHODS: The cost-effectiveness analysis was based on data from a randomized double-blind, placebo-controlled trial. A decision-tree analysis was employed, including Monte Carlo and bootstrapping techniques. This study was a sub-study of the EUROPA (European Trial on Reduction of Cardiac Events with Perindopril in Stable Coronary Artery Disease) trial (n = 12 218; mean follow-up 4.2 years). Resource use was based on data from Polish EUROPA study patients (n = 1251), while effectiveness was based on the whole EUROPA study. The health gain of perindopril in life-years was based on overall EUROPA study results, and the adapted Polish life expectancy of patients not dying during the trial. Costs were calculated in new Polish zloty (PLN), year 2003 values; euro1 = PLN4.053. Only direct healthcare costs related to cardiovascular events and medication use were studied. RESULTS: When observed mortality was combined with life expectancy beyond the end of the study, perindopril use showed a gain in life expectancy of 0.182 life-years (SD +/- 0.129) at a cost of PLN1983 (SD +/- 103) with discounting of 5% per annum on costs and no discounting on effects. This resulted in an incremental cost-effectiveness ratio (ICER) of PLN10 896 per life-year gained. The probability that the ICER for perindopril was below the threshold of PLN60 000 was 88%. The overall results were insensitive to discount rates for costs and life-years. CONCLUSIONS: Perindopril leads to a reduction in the risk of coronary events among patients with stable heart disease. When the expected improvement in life expectancy is combined with associated medical costs, there is a high probability that perindopril is cost effective, given the threshold of PLN60 000 per life-year gained.  相似文献   
88.
目的探讨醋酸铅对豚鼠内侧橄榄耳蜗传出神经的损害。方法 70只成年健康豚鼠随机分为对照组和实验组。对照组(10只)豚鼠腹腔注射生理盐水1ml,共7次。实验组又分为高铅组和低铅组(各30只),分别每天1次腹腔注射0.25%醋酸铅溶液40mg/kg和10mg/kg,连续一周,分别于停药后14、28天(各15只))进行血铅含量和畸变产物耳声发射(DPOAE)检测,检测完成后断头处死,行基底膜铺片染色。结果实验组醋酸铅染毒后,血清中铅含量迅速升高。对照组和低铅组耳蜗传出神经分布均匀,神经纤维连续,DPOAE出现了不同程度的对侧声抑制效应,低铅组14天和28天抑制幅度分别为3.06±1.19dB和2.86±1.33dB;高铅组14天后耳蜗传出神经纤维连续性中断,乙酰胆碱酯酶终末反应物减少,DPOAE对侧声抑制幅度下降为0.74±0.61dB;高铅组28天后传出神经损害最为显著,DPOAE未引出。结论铅可对豚鼠内侧橄榄耳蜗传出神经产生不可逆性的损害。  相似文献   
89.
The KEYNOTE‐659 study evaluated the efficacy and safety of first‐line pembrolizumab plus S‐1 and oxaliplatin (SOX) (cohort 1) or S‐1 and cisplatin (SP) (cohort 2) for advanced gastric/gastroesophageal junction (G/GEJ) cancer in Japan. Herein, we update the results of cohort 1 and describe the results of cohort 2. This open‐label phase IIb study enrolled patients with advanced programmed death‐ligand 1 (PD‐L1)‐positive (combined positive score ≥ 1) human epidermal growth factor receptor 2 (HER2)‐negative G/GEJ adenocarcinoma. The primary end‐point was the objective response rate (ORR). Other end‐points were duration of response (DOR), disease control rate (DCR), progression‐free survival (PFS), overall survival (OS), and safety. One hundred patients were enrolled. In cohorts 1 and 2, median follow‐up time was 16.9 and 17.1 months; ORR (central review), 72.2% and 80.4%; DOR, 10.6 and 9.5 months; DCR (central review), 96.3% and 97.8%; median PFS (central review), 9.4 and 8.3 months; and median OS, 16.9 and 17.1 months, respectively. Treatment‐related adverse events (TRAEs) occurred in all patients, including peripheral sensory neuropathy (94.4%, cohort 1), decreased neutrophil count (82.6%, cohort 2), nausea (59.3% and 60.9% in cohorts 1 and 2), and decreased appetite (61.1% and 60.9% in cohorts 1 and 2). Grade 3 or higher TRAEs were reported by 59.3% (cohort 1) and 78.3% (cohort 2), including decreased platelet count (14.8%, cohort 1) and decreased neutrophil count (52.2%, cohort 2). Pembrolizumab in combination with SOX or SP showed favorable efficacy and safety in patients with PD‐L1‐positive, HER2‐negative G/GEJ adenocarcinoma.  相似文献   
90.
A 58-year-old man was diagnosed as having type 3 gastric cancer (poorly differentiated adenocarcinoma). He underwent total gastrectomy with splenectomy, as well as D3 dissection, and received postoperative chemotherapy combining oral uracil and futrafur (UFT) with cisplatin (CDDP), but results showed recurrence of multiple abdominal lymph node metastases around the aorta. He therefore received various anticancer drug regimens (irinotecan [CPT-11]/CDDP; 1 M tegafur-0.4 M gimeracil-1 M oteracil potassium [TS-1], methotrexate (MTX)/5-fluorouracil); however, final results showed growth of lymph node metastasis and simultaneous worsening of his general condition. The patient then received combined administration of doxifluridine (5′-DFUR)/docetaxel (5′-DFUR, 1000 mg/body [666.7 mg/m 2 ], given by consecutive daily administration, orally, for days 1–14; and docetaxel, 80 mg/body [60 mg/m 2 ], on day 8, by venous drip, every 3 weeks). Three courses of this regimen resulted in approximately 90% reduction of the abdominal lymph node size, disappearance of the right cervical lymph node metastasis, reductions of the levels of two tumor markers (carcinoembryonic antigen [CEA] and carbohydrate antigen [CA]19-9), and improvement of his general condition. In total, seven courses of the regimen were carried out. The patient died on day 298 after starting this combined regimen and showed a response period of 126 days. The primary toxicity identified was neutropenia (grade 4), as well as other low-grade (grade 1, 2) hematological and nonhematological toxicities. In the field of gastric cancer treatment, especially for patients showing multiple resistance to anticancer drugs, an effective therapy is critically needed. Received: January 15, 2002 / Accepted: July 8, 2002 Offprint requests to: A. Sato  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