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   81025篇
  免费   7862篇
  国内免费   5928篇
耳鼻咽喉   582篇
儿科学   917篇
妇产科学   629篇
基础医学   8002篇
口腔科学   1351篇
临床医学   10347篇
内科学   10515篇
皮肤病学   617篇
神经病学   3772篇
特种医学   3193篇
外国民族医学   39篇
外科学   8307篇
综合类   17142篇
现状与发展   14篇
一般理论   16篇
预防医学   6850篇
眼科学   1615篇
药学   9155篇
  82篇
中国医学   5565篇
肿瘤学   6105篇
  2024年   289篇
  2023年   1118篇
  2022年   2903篇
  2021年   3604篇
  2020年   3015篇
  2019年   2302篇
  2018年   2496篇
  2017年   2476篇
  2016年   2227篇
  2015年   3730篇
  2014年   4686篇
  2013年   4727篇
  2012年   7071篇
  2011年   7872篇
  2010年   5600篇
  2009年   4732篇
  2008年   5232篇
  2007年   5067篇
  2006年   4730篇
  2005年   4231篇
  2004年   2931篇
  2003年   2534篇
  2002年   2153篇
  2001年   1671篇
  2000年   1497篇
  1999年   1148篇
  1998年   771篇
  1997年   746篇
  1996年   580篇
  1995年   521篇
  1994年   387篇
  1993年   285篇
  1992年   240篇
  1991年   195篇
  1990年   189篇
  1989年   182篇
  1988年   138篇
  1987年   129篇
  1986年   98篇
  1985年   95篇
  1984年   52篇
  1983年   33篇
  1982年   28篇
  1981年   24篇
  1980年   15篇
  1979年   17篇
  1978年   7篇
  1973年   5篇
  1972年   6篇
  1971年   4篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
We previously reported that lymphatic mapping using isosulfan blue can be used to identify sentinel nodes (SNs). This study was undertaken to evaluate the feasibility of using the SN technique in treating early gastric cancer and to explore its usefulness for minimal invasive surgery. Twenty-three patients with early gastric cancer who underwent SN biopsy were retrospectively evaluated. Based on SN evaluation, individualized surgery was performed in five patients with T1N0M0 gastric cancer. When pathological examination of frozen sections revealed metastasis in SNs, we performed a standard D2 gastrectomy. Laparoscopic local resection was applied when the SN biopsy was negative. Our results showed that the success rate with SN biopsy in early gastric cancer was 100%, as were the accuracy, sensitivity, and specificity. All five patients with early gastric cancer had SNs negative for metastases both by frozen section and by postoperative pathology. Thus, all these patients underwent laparoscopic local resection without extended lymphadenectomy. We conclude that SN biopsy is a useful tool to individualize the operative procedure, and laparoscopic local resection can be safely performed using SN guidance in selected patients with early gastric cancer.  相似文献   
62.
本文应用核磁共振法(NMR)测定了几种混合体系的 HLB 值与混合体系中各组分的 HLB 值。实验结果表明,混合体系中各组分在核磁共振图谱中的积分曲线高度也具有加和性。混合体系的 HLB 值是体系中各组分 HLB 值的加权平均值。因此,对混合体系的 HLB 值可以应用 NMR 法直接测定,也可应用 NMR 法测定各组分的 HLB值,通过计算求得,计算值与实测值完全一致。  相似文献   
63.
Monoclonal antibody 131I-COC183B2, developed in our laboratory and proved to fit for human treatment was injected intraperitoneally or subcutaneously in 13 patients. In 8 cases with i.p. injection the disease corresponded with the image, i.e. 3 primary ovarian epithelial cancers showed positive images, 1 ovarian Krukenberg tumor was negative and the other 4 negative images included 1 uterine myoma and 3 ovarian teratomas. In the subcutaneous injection group, 4 cases had ovarian carcinoma, surgery and chemotherapy. Two negative images corresponded with the clinical status-in good health, another negative case had metastatic left supraclavicular lymph node due to ovarian mucinous adenocarcinoma. The last negative image in this group was a case of benign ovarian teratoma which was proved after surgery. The 1 positive case was waiting to be proved by a scheduled third operation. The computer scintigram calculation of T/NT was 5.35 to 13.7. The results suggest that this monoclonal antibody can be used for radioimmunoimaging for the localization of ovarian carcinoma, which is not only helpful for clinical staging and differential diagnosis but is also a good follow-up method.
  相似文献   
64.
While extensive evidence suggests that adrenoceptors play an important role in the control of growth hormone in the rat, there are few studies involving the direct measurement of growth hormone-releasing hormone (GHRH). We have therefore developed a radioimmunoassay for rat GHRH, and used it to investigate the modulation of GHRH release by noradrenaline from incubated rat hypothalamus in vitro. The GHRH radioimmunoassay had no significant cross-reactivity with other hypothalamic or GHRH-related peptides, and was sensitive to 4 pg/tube; intra- and interassay coefficients of variation were 6% and 12% respectively. Single incubated rat hypothalami produced a stable and readily measurable output of GHRH in successive 20 min incubations after an initial 60 min preincubation; the release of GHRH was increased in the presence of 56 mM KCI, but did not respond to KCI-depolarization when calcium was excluded from the medium. Stimulated GHRH release was identical to synthetic rat GHRH(1–43) on high-performance liquid chromatography and Sephadex G-75 chromatography.
Noradrenaline stimulated GHRH secretion in a dose-dependent manner in the concentration range 10−10— 10−6M, with a plateau in response at 10−7M. Stimulation with noradrenaline 10−7M was blocked by idazoxan 10−5M and attenuated by thymoxamine 10−5M, but was unaffected by timolol 10−5M. Both the α2-adrenoceptor agonist guanfacine, and the α1-adrenoceptor agonist methoxamine, specifically stimulated GHRH secretion.
It is concluded that noradrenaline stimulates the release of GHRH at both α1 and α2-adrenoceptors.  相似文献   
65.
目的:观察超声电丛刺头穴丛刺法治疗急性脑梗死的效果,以及治疗前后体感诱发电位指标及血液生化指标变化。方法:①选择2003-01/2005-06在沈阳脑科医院神经内科住院的急性脑梗死患者261例,男160例,女101例。均为首次患病,且对治疗方案知情同意。将上述患者随机分为2组:丛刺治疗组131例,对照组130例。②丛刺治疗组:采用超声电丛刺治疗仪于头部电丛刺顶区(运动区),以100~200Hz疏密波电针通过6~8h,1次/d,1个疗程30次。对照组:均予以常规脑血管病药物同等治疗。丛刺治疗组和对照组均干预30d。两组疗效判定标准:治疗后神经功能缺损评分减少91%~100%为基本恢复,减少46%~90%为显著进步,减少18%~45%为进步。③采用酶联免疫法测定血浆α-颗粒膜蛋白水平;应用放射免疫法测定血浆血栓素A2水平;采用酶联免疫吸附法双抗体夹心法测定血浆D-二聚体水平;采用免疫透射比浊方法测定脂蛋白(a)水平。应用神经电生理检测仪检测体感诱发电位。④计数和计量资料差异比较采用χ2检验和t检验。结果:急性脑梗死患者261例均进入结果分析。①丛刺治疗组131例中:基本恢复31例,显著进步80例,进步15例,总有效率为96%(126/131);对照组130例:基本恢复14例,显著进步68例,进步12例,总有效率为72%(96/130);丛刺治疗组总有效率明显高于对照组(P<0.01)。②丛刺治疗组治疗后血浆α-颗粒膜蛋白、血栓素A2、D-二聚体和脂蛋白(a)含量较治疗前明显降低(P<0.01)。③丛刺治疗组治疗后体感诱发电位的波潜伏期与传导时间较治疗前明显缩短(P<0.01)。结论:超声电丛刺治疗急性脑梗死效果显著,可显著改善急性脑梗死患者体感诱发电位指标及血液生化指标。  相似文献   
66.
目的观察JAK2激酶抑制剂AG490对结肠癌HT-29细胞侵袭以及对基质金属蛋白酶-2(MMP-2)表达的影响,探讨STAT3信号转导通路在结肠癌侵袭转移调控中的作用。方法应用JAK2激酶抑制剂AG490处理结肠癌HT-29细胞,Matrigel肿瘤体外侵袭模型检测肿瘤细胞侵袭;Western blot检测STAT3蛋白表达;逆转录-聚合酶链反应(RT—PCR)检测MMP2mRNA表达。结果AG490可抑制JAK2/STAT3信号转导通路活化及结肠癌HT-29细胞侵袭,在此过程中AG490在mRNA水平抑制MMP-2表达。结论STAT3信号转导通路参与结肠癌细胞侵袭调控,阻断STAT3通路活化可抑制结肠癌细胞侵袭,这一作用可能是通过抑制MMP-2表达实现的。  相似文献   
67.
This paper is a summary of our observations on 105 cases of infantile spasms. The age of onset was around six months after birth, but the patients came for treatment mainly about one year after onset. Fever of unknown cause, asphyxia, birth injury, infection of the central nervous system, tuberous sclerosis, phenylketonuria and recent immunization etc. were complained. Clinically, it is characterized by head nodding, mental retardation, myoclonic jerks and various neurologic deficits. EEG findings showed classical or modified arrythmia or other epileptiform patterns. About one third of 22 cases examined had abnormal brain stem auditory evoked potentials. Among 42 patients who underwent CT scanning before ACTH treatment, 18 were normal and 7 abnormal; during ACTH treatment 3 normal and 4 abnormal; after completion of treatment, 4 normal and 6 abnormal, suggesting no further atrophy of the brain. Examination of trace elements of the hair by particle-induced X-ray emission (PIXE) method in 23 patients revealed a significant difference in lead, calcium and zinc contents between patients and 101 controls, but no statistical difference in iron and copper contents between the two groups. Sodium valproate, prednisone and ACTH appear to be effective in the treatment of infantile spasms. Eight patients fully recovered, and they can go to school without difficulty. Many patients derived various degrees of improvement to the satisfaction of their parents. Two patients were still amented and often attacked by myoclonus. The effects, side effects of these drugs, and the possible pathogenesis were discussed.
  相似文献   
68.
腹腔镜胆囊切除术360例Calot三角解剖与临床   总被引:5,自引:3,他引:2  
目的 通过腹腔镜胆囊切除术(Laparoscopic Cholecystec-tomy,LC),探讨Calot三角的解剖关系。方法 从Calot三角分离出胆囊动脉、胆囊管,辨认胆总管和肝总管的走向。结果 我们1998年9月~2004年6月共完成360例LC术进行分析。结论 解剖Calot三角是胆囊切除术中重要的步骤,也是预防医源性损伤的关键。  相似文献   
69.
便秘是老年糖尿病患者的常见合并症之一.笔者自2006年6月~2007年6月以济川煎为基础方加味治疗老年糖尿病患者合并便秘24例,现报道如下.   ……  相似文献   
70.
全腹膜外补片植入术中补片不固定的实验研究   总被引:4,自引:3,他引:1  
目的评价全腹膜外补片植入术中补片不固定的安全性和有效性。方法将50只SD大鼠建立疝缺损(3cm2)模型,按随机数字表分为2组,使用聚丙烯补片(12 cm2)采用腹膜外补片植入术进行修复。甲组为补片固定组,乙组为补片不固定组。大鼠于术后不同时间分批处死,记录补片的挛缩度、腹壁抗张强度以及组织细胞学变化。结果所有大鼠术后腹腔均无粘连。2组大鼠在术后7 d、14 d、30 d、60 d和90 d补片的挛缩度分别为6.7%±1.3%vs 7.3%±1.5%、12.3%±1.3%vs 12.4%±1.6%、14.0%±2.0%vs 14.5%±1.3%、17.4%±2.1%vs 18.4%±1.5%和18.9%±2.2%vs19.5%±2.6%(P>0.05);2组大鼠的腹壁抗张强度分别为(288.4±8.4)mm Hg vs(286.6±10.2)mm Hg、(300.4±11.2)mm Hg vs(298.8±11.4)mm Hg、(305.0±11.7)mm Hg vs(303.3±16.1)mm Hg、(309.0±10.8)mm Hg vs(307.6±8.9)mm Hg和(311.8±9.8)mm Hg vs(310.0±8.6)mm Hg(P>0.05);2组大鼠的组织细胞学变化一致。结论当补片面积是大鼠疝缺损的4倍以上时,不固定的腹膜外补片植入术是安全有效的。  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