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   59340篇
  免费   5491篇
  国内免费   4185篇
耳鼻咽喉   648篇
儿科学   610篇
妇产科学   575篇
基础医学   6063篇
口腔科学   879篇
临床医学   7520篇
内科学   8043篇
皮肤病学   578篇
神经病学   2794篇
特种医学   2327篇
外国民族医学   36篇
外科学   6411篇
综合类   10983篇
现状与发展   13篇
一般理论   3篇
预防医学   4243篇
眼科学   1628篇
药学   6467篇
  53篇
中国医学   4229篇
肿瘤学   4913篇
  2024年   253篇
  2023年   868篇
  2022年   2333篇
  2021年   2968篇
  2020年   2418篇
  2019年   1877篇
  2018年   2022篇
  2017年   2011篇
  2016年   1825篇
  2015年   2907篇
  2014年   3654篇
  2013年   3371篇
  2012年   4912篇
  2011年   5277篇
  2010年   3676篇
  2009年   2990篇
  2008年   3436篇
  2007年   3181篇
  2006年   3084篇
  2005年   2865篇
  2004年   1868篇
  2003年   1765篇
  2002年   1454篇
  2001年   1210篇
  2000年   1123篇
  1999年   1055篇
  1998年   658篇
  1997年   588篇
  1996年   485篇
  1995年   455篇
  1994年   347篇
  1993年   262篇
  1992年   315篇
  1991年   307篇
  1990年   210篇
  1989年   163篇
  1988年   184篇
  1987年   154篇
  1986年   101篇
  1985年   80篇
  1984年   61篇
  1983年   32篇
  1982年   29篇
  1981年   31篇
  1980年   24篇
  1979年   38篇
  1978年   13篇
  1977年   11篇
  1975年   11篇
  1973年   12篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
31.
The immediate, short-term and long-term depressor effects, the immediate effects on cardiac functions in grade II and grade III vascular hypertension, and the effects on angiotensin II in grade III vascular hypertension by acupuncture at otoacupoint Heart were studied in 30 cases of vascular hypertensive patients. The immediate depressor effect of acupuncture at otoacupoint Stomach was also recorded for comparison. It was found that acupuncture at otoacupoint Heart produced marked immediate depressor effect, and the short-term effective rate was 100%, the long-term effective rate was 63.3%, as well as evident immediate effects on cardiac functional activities in grade II and grade III hypertension and marked effects on angiotensin II in grade III hypertension. Acupuncture at otoacupoint Stomach produced no depressor effect on vascular hypertension.  相似文献   
32.
51例应用Begg正畸技术矫治错畸形,各种类型的牙性及轻度骨性错畸形,均取得满意的效果。对牙轴唇倾并伴有深覆的安氏Ⅱ类错打开咬合、内收前牙的效果尤佳。  相似文献   
33.
超声引导下肿瘤内注射^90钇玻璃微球的肝癌综合治疗   总被引:12,自引:0,他引:12  
董宝玮  梁萍 《中华医学杂志》1994,74(8):471-473,T048
超声引导下对28例肝癌病人进行了肿瘤内注射^90钇玻璃微球(Y-90GT MS)为主的综合性治疗(部分病人配合肿块周边注射无水酒精及门静脉穿刺化疗)。随访2~16个月(平均7.9个月),病人全健在。肿瘤缩小率为91%,其中显著缩小达75%;肿块回声呈致密增强,少数呈混合型或等回声型;肿瘤内及周边血流信号显著减少;原甲胎蛋白升高者13例,11例显著下降,其中6例降至正常;病人症状减轻,全身情况改善。  相似文献   
34.
The over-representation of chromosome 12p sequences is crucial for the development of invasive testicular germ cell tumors. Testicular cancer patients may have metastatic tumors of diverse histologic types, including adenocarcinoma, undifferentiated carcinoma, sarcoma, or other malignancies that lack features of germ cell tumors. We sought to investigate the possible germ cell origin of such tumors using interphase fluorescence in situ hybridization. In all, 10 metastatic malignant somatic-type tumors from patients with histories of testicular cancer, as well as one malignant somatic-type tumor from a patient with primary mediastinal germ cell tumor were studied and included: adenocarcinoma (five cases), poorly differentiated carcinoma (one), sarcoma (four), and neuroendocrine carcinoma (one). The tumors were analyzed using fluorescence in situ hybridization using 12p spectrum green and 12 centromeric spectrum orange probes in paraffin sections. The patients ranged in age from 27 to 55 years (mean, 43). Colon and lung cancers from patients without germ cell tumors were used as controls. Adequate signals were observed in all tumors. Gain of chromosome 12p was seen in six tumors. None of the control tumors showed 12p amplification. Fluorescence in situ hybridization for 12p amplification in routinely processed surgical specimens is a useful adjuvant diagnostic tool in confirming the germ cell origin of metastatic tumors having the histologic appearance of somatic-type neoplasms.  相似文献   
35.
OBJECTIVE: Septal-lateral annular cinching ('SLAC') corrects both acute and chronic ischemic mitral regurgitation in animal experiments, which has led to the development of therapeutic surgical and interventional strategies incorporating this concept (e.g., Edwards GeoForm ring, Myocor Coapsys, Ample Medical PS3). Changes in left ventricular (LV) transmural cardiac and fiber-sheet strains after SLAC, however, remain unknown. METHODS: Eight normal sheep hearts had two triads of transmural radiopaque bead columns inserted adjacent to (anterobasal) and remote from (midlateral equatorial) the mitral annulus. Under acute, open chest conditions, 4D bead coordinates were obtained using videofluoroscopy before and after SLAC. Transmural systolic strains were calculated from bead displacements relative to local circumferential, longitudinal, and radial cardiac axes. Transmural cardiac strains were transformed into fiber-sheet coordinates (X(f), X(s), X(n)) oriented along the fiber (f), sheet (s), and sheet-normal (n) axes using fiber (alpha) and sheet (beta) angle measurements. Results: SLAC markedly reduced (approximately 60%) septal-lateral annular diameter at both end-diastole (ED) (2.5+/-0.3 to 1.0+/-0.3 cm, p=0.001) and end-systole (ES) (2.4+/-0.4 to 1.0+/-0.3 cm, p=0.001). In the LV wall remote from the mitral annulus, transmural systolic strains did not change. In the anterobasal region adjacent to the mitral annulus, ED wall thickness increased (p=0.01) and systolic wall thickening was less in the epicardial (0.28+/-0.12 vs 0.20+/-0.06, p=0.05) and midwall (0.36+/-0.24 vs 0.19+/-0.11, p=0.04) LV layers. This impaired wall thickening was due to decreased systolic sheet thickening (0.20+/-0.8 to 0.12+/-0.07, p=0.01) and sheet shear (-0.15+/-0.07 to -0.11+/-0.04, p=0.02) in the epicardium and sheet extension (0.21+/-0.11 to 0.10+/-0.04, p=0.03) in the midwall. Transmural systolic and remodeling strains in the lateral midwall (remote from the annulus) were unaffected. CONCLUSIONS: Although SLAC is an alluring concept to correct ischemic mitral regurgitation, these data suggest that extreme SLAC adversely effects systolic wall thickening adjacent to the mitral annulus by inhibiting systolic sheet thickening, sheet shear, and sheet extension. Such alterations in LV strains could result in unanticipated deleterious remodeling and warrant further investigation.  相似文献   
36.
BACKGROUND AND PURPOSE: The potential risk of prolongation of treatment time in cervical cancer has been reported for many low-dose rate (LDR) studies, with an estimated loss of local control ranging from 0.3 to 1.6% per day of treatment prolongation. Since the treatment schedule for fractionated high-dose rate intracavitary brachytherapy (HDRICB) is not directly comparable with that for low-dose rate studies, this report aims to evaluate the adverse effect of treatment prolongation specifically for cervical cancer treated with HDRICB. MATERIAL AND METHODS: From September 1992 to December 1997, 257 patients diagnosed with uterine cervical cancer (35 Ib, 26 IIa, 122 IIb, 10 IIIa, 57 IIIb, 7 IVa), who underwent external radiotherapy combined with between two and four courses of HDRICB and a minimum of 3 years of follow-up (median 57 months), were analyzed. Treatment consisted of irradiation of the whole pelvis with 44-45 Gy consisting of 22-25 fractions by 5 weeks, with the dose boosted to 54-58 Gy (with central shielding) for patients diagnosed as FIGO stage IIb-IVa bilateral parametrial disease. HDRICB was performed using an Ir-192 remote afterloading technique at 1-week intervals. The standard prescribed dose for each course of HDRICB was 7.2 Gy to point A for three insertions (before July 1995), or 6.0 Gy to point A for four insertions (after July 1995). Total prescribed point A doses (external beam radiotherapy+HDRICB) ranged from 58 to 71.6 Gy (median, 65.6 Gy) for stage IB-IIA, while analogous dosage for larger lesions (stage IIb-IVa) ranged from 59 to 75.6 Gy (median, 65.6 Gy). Kaplan-Meier and multivariate analyses were used to test the effect of treatment time on pelvic control rate (PCR) and cause-specific survival (CSS) at 5 years. RESULTS: Median treatment time was 63 days. For all stages of disease, the 5-year CSS and PCR were significantly different comparing treatment times of less than and greater than or equal to 63 days [83% and 65% (P=0.004], 93% and 83% (P=0.02), respectively]. These associations were also significant for stage Ib/IIa [97% and 79% (P=0.01), and 100% and 87% (P=0.02), respectively), but not for stage IIb [75% and 72% (P=0.79), and 93% and 87% (P=0.83), respectively] or stage III [66% and 49% (P=0.2), and 83% and 72% (P=0.21), respectively]. Multivariate analysis identified three prognostic factors for CSS, stage (P<0.001), tumor response to external RT (P=0.001), and overall treatment time (OTT; P=0.006). Prognostic factors for pelvic failure were stage (P<0.001), tumor response to external RT (P=0.001), and OTT (P=0.03). Prolongation of treatment time resulted in a daily decrease in pelvic control rate of 0.67% overall, and 0.43% for stage Ib-IIa, 0.57% for stage IIb, and 0.73% for stage III patients. CONCLUSION: Analysis of the data from the current study demonstrates that the adverse effect of treatment prolongation was observed later in the treatment course for the high-dose rate (HDR) series compared to the LDR analog, however, treatment-time prolongation still negatively influenced the cause-specific survival and pelvic control rate for both dosage groups.  相似文献   
37.
河北磁县食管癌胃癌高发人群口腔真菌分布的调查   总被引:1,自引:0,他引:1  
应用常规方法随机研究食管癌、胃癌高发的磁县人群547例的口腔真菌。结果:1.口腔真菌阳性率为68.4%,食管真菌阳性率为47.3%,前者显著高于后者(P<0.001)。2.口腔真菌以念珠菌、曲霉菌和青霉菌为主,食管真菌以曲霉菌、青霉菌和念珠菌占多数。3.口腔与食管内的产毒真菌差异无显著性意义(P>0.05)。本结果为进一步研究口腔真菌与上消化道癌及肿瘤的一级预防提供了依据。  相似文献   
38.
    
Summary Hypodermic needle shields may be used as tip protectors for several types of microsurgical instruments. These provide an inexpensive alternative to commercially available tip covers.  相似文献   
39.
本文报告等容血液稀释(简称DH)治疗高血压病75例,总有效率为90.2%,48例随访2年血压下降稳定持久,血液流变学改善,总有效率为87.5%。结果表明:HD治疗高血压病可以改善血流高粘滞状态,降低血液粘度,增强血液流动性,减少血流阻力,改善微循环灌流,从而达到降低血压和改善器官血流,达到持久降压及减少器官合并症。一次HD与降压药适量配伍,疗效更显著而持久,可维持数月至2年以上。  相似文献   
40.
ATP和SNP控制性降压对血流动力学的影响   总被引:1,自引:1,他引:0  
对比研究三磷酸腺苷(ATP)和硝普钠(SNP)控制性降压对氯胺酮麻醉犬血流动力学的影响。选择犬14只,随机分为ATP组和SNP组,由股静脉持续输入ATP和SNP使MAP降低30% ̄40%,维持30min,分别于降压前、降压后15min、30min及停止降压后15min用Swan-Ganz漂浮导管测定血流动力学指标。结果表明,ATP、SNP降压期间SVR、LVSW显著降低,CO、PCWP、SV、RV  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