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   6911篇
  免费   318篇
  国内免费   39篇
耳鼻咽喉   88篇
儿科学   140篇
妇产科学   74篇
基础医学   760篇
口腔科学   228篇
临床医学   400篇
内科学   1402篇
皮肤病学   165篇
神经病学   498篇
特种医学   373篇
外科学   1317篇
综合类   54篇
一般理论   1篇
预防医学   163篇
眼科学   129篇
药学   468篇
中国医学   12篇
肿瘤学   996篇
  2023年   37篇
  2022年   66篇
  2021年   109篇
  2020年   65篇
  2019年   105篇
  2018年   112篇
  2017年   84篇
  2016年   146篇
  2015年   171篇
  2014年   185篇
  2013年   201篇
  2012年   289篇
  2011年   304篇
  2010年   245篇
  2009年   196篇
  2008年   279篇
  2007年   262篇
  2006年   264篇
  2005年   272篇
  2004年   257篇
  2003年   225篇
  2002年   224篇
  2001年   213篇
  2000年   246篇
  1999年   215篇
  1998年   101篇
  1997年   116篇
  1996年   94篇
  1995年   81篇
  1994年   80篇
  1993年   70篇
  1992年   178篇
  1991年   151篇
  1990年   161篇
  1989年   206篇
  1988年   167篇
  1987年   156篇
  1986年   139篇
  1985年   107篇
  1984年   77篇
  1983年   72篇
  1982年   34篇
  1980年   32篇
  1979年   60篇
  1978年   46篇
  1977年   45篇
  1973年   28篇
  1972年   40篇
  1971年   33篇
  1969年   29篇
排序方式: 共有7268条查询结果,搜索用时 15 毫秒
91.
Branhamella catarrhalis has been misconsidered as a normal resident in human respiratory tract for a long time. However, many authors recently have reported its pathogenecity and isolated it from the otolaryngological region. In our study, this organism can be isolated from the ear and nasal discharge in the child with acute otitis media by the rate of 7.5% and 21.4% respectively. Out of this 107 isolated strains, 97 strains (90.7%) were found to be beta-lactamase producing organisms. The MIC measurement of penicillins and cephems (except CEX) for inhibition of all these strains in our study is 6.25 micrograms/ml or less and because of the unreliability of the ABPC's susceptibility test by disk method, it is necessary to check the beta-lactamase production in each strain. Becoming of the high emergence rate of beta-lactamase producing strains, B. catarrhalis should be considered to be as important pathogen as Streptococcus pneumoniae and Haemophilus influenzae in upper respiratory tract infections in children.  相似文献   
92.
In an attempts to increase the antitumor effect and to reduce normal tissue toxicity, the combined cytotoxic effect of cis-Diamminedichloroplatinum (II) (CDDP) and cis-diammine(1,1-cyclobutane dicarboxylate) platinum (II) (CBDCA) was investigated using HeLa and colon 26 cell lines and the combination index (CI). Cytotoxicity of the combination of CDDP and CBDCA on 27 surgically resected specimens of human gastric and colorectal adenocarcinomas was also evaluated using the in vitro succinate dehydrogenase inhibition (SDI) test. The CI values varied with the dose ratio examined (1:1-1:6) of CDDP and CBDCA, with findings that CI<1, synergy, was obtained at fraction affected (Fa)>0.75 for HeLa cells and at Fa<0.9 for colon 26 cells in cases of a dose ratio of 1:1 to 1:2. Of all 27 clinical human adenocarcinomas, the succinate dehydrogenase (SD) activity was significantly lower in cancer cells concomitantly exposed to both CDDP and CBDCA than in those exposed to either drug alone. These positive effects of a combination of two platinum analogues on human malignant tissues have heretofore not been reported, which would warrant the clinical application of this combination for human malignant tumors.  相似文献   
93.
Precise anatomy of the vesico-uterine ligament for radical hysterectomy   总被引:4,自引:0,他引:4  
OBJECTIVES: To clarify the anatomy of the vesico-uterine ligament (VUL), we meticulously separated the VUL under magnification (x2.5) during Okabayashi's radical hysterectomy. METHODS: Fifty-nine patients (TNM nomenclature: pTIb: 39, pT2a: 5, pT2b: 7, after trans-arterial anticancer-drug infusion treatment for the cervical cancer: 8) underwent this meticulous operation. Blood loss was recorded at two separate time points: during the separation of the VUL and after removal of the uterus. RESULTS: After complete separation of the uterine artery and superficial uterine vein from the ureter, we could identify the genuine connective tissue of the anterior leaf of the VUL in which we isolate and divide a distinct bundle of blood vessels: the cervicovesical vessels that cross over the ureter from the bladder to the cervix. The remaining tissues in the anterior leaf is only avascular connective tissue. The posterior leaf of the VUL is the tissue residing under the ureter connecting the posterior wall of the bladder and the lateral cervix/upper lateral vagina. In the connective tissues, we identified the middle and inferior vesical veins connecting with the deep uterine vein. The division of these veins could separate the urinary bladder with ureters completely from the lateral cervix and upper vagina. The mean blood loss during the separation of the VUL was 20+/-10 g (N=59) and after radical hysterectomy was 189+/-91.6 g (N=59). CONCLUSION: A precise network of blood vessels in the VUL is identified. The knowledge of this anatomy is important to perform radical hysterectomy.  相似文献   
94.
95.
96.
97.
Interstitial pneumonia (IP) is a major risk factor for lung adenocarcinoma (LADC). IP-related LADC predominantly develops in the bronchiolar metaplasia lining in honeycomb lesions. Kirsten rat sarcoma virus (KRAS) is the most common oncogene mutated in IP-related LADC. The present study examined the metaplastic epithelia in honeycomb lesions for KRAS mutations using digital droplet polymerase chain reaction (ddPCR), a sensitive method used to detect infrequent mutations. Significantly higher KRAS mutation variant allele frequencies (VAFs) were detected in the metaplastic lung epithelia from 13 patients with IP compared with those in 46 non-lesioned lung samples from patients without IP (G12V, P=0.0004, G12C, P=0.0181, and G12A, P=0.0234; Mann Whitney U test). Multivariate analyses revealed that higher KRAS G12V (logistic regression model; P=0.0133, odds ratio=7.11) and G12C (P=0.0191, odds ratio=5.81) VAFs in patients with IP were independent of confounding variables, such as smoking and age. In patients with IP, metaplastic epithelia exhibited significantly higher KRAS G12V and G12C VAFs compared with the non-lesioned counterparts (paired t-test; G12V, P=0.0158, G12C, P=0.0465). These results suggested that IP could increase KRAS mutations and supported the hypothesis that bronchiolar metaplasia could be a precursor for IP-related LADC.  相似文献   
98.
Purpose  The aim of this study was to assess the variation of probe rotation angles for detecting a single needle using sagittal images of transrectal ultrasonography (TRUS). Materials and methods  A phantom study was performed. One needle was inserted through each of 10 holes of the template, and variations in the probe rotation angles for detecting the needle were measured. Results  The mean variation of probe rotation for detecting a single needle was 17.0° (range 4°–25°). Slightly broader variation was seen for the needle in holes farther away from the probe. Conclusion  Probe rotation angles for detecting a single needle displayed considerable variation. Seed locations recognized on sagittal imaging by TRUS are thus indeterminate, and real-time dose calculations using TRUS for 125I seed implantation should be used with care.  相似文献   
99.
目的:性治疗法目前尚未普及,本研究旨在评价性治疗法联合西地那非治疗勃起功能障碍(ED)的疗效。方法:根据治疗方法的不同将在本院治疗随访过的3130例维吾尔族ED患者分成2组。对照组625例,单纯口服西地那非3个月;试验组2505例,采用性治疗法联合西地那非治疗3个月。采用国际勃起功能问卷表(IIEF-5)在各组治疗前、后进行疗效评估,并随访12个月。结果:对照组治疗前、后及在6个月、12个月随访的IIEF-5评分分别为12.80±3.76、18.10±2.61、17.35±2.73和16.64±2.63;试验组治疗前、后及在6个月、12个月随访的IIEF-5评分分别为12.73±3.52、19.06±4.07、19.86±2.42和20.47±2.38。两组治疗前后IIEF-5评分自身对比差异均有显著性(P<0.05)。组间比较,试验组较对照组6个月和12个月随访IIEF-5评分均有显著性差异(P<0.05)。结论:性治疗法联合西地那非治疗ED的效果优于单纯西地那非治疗,并在12个月的随访中稳定性良好。  相似文献   
100.
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