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   115204篇
  免费   9405篇
  国内免费   6088篇
耳鼻咽喉   1079篇
儿科学   1891篇
妇产科学   1085篇
基础医学   12129篇
口腔科学   2065篇
临床医学   14165篇
内科学   15605篇
皮肤病学   1908篇
神经病学   5387篇
特种医学   4438篇
外国民族医学   26篇
外科学   10210篇
综合类   21410篇
现状与发展   23篇
一般理论   8篇
预防医学   10577篇
眼科学   2599篇
药学   12231篇
  83篇
中国医学   6341篇
肿瘤学   7437篇
  2024年   224篇
  2023年   1018篇
  2022年   2638篇
  2021年   3743篇
  2020年   2860篇
  2019年   2544篇
  2018年   2754篇
  2017年   2861篇
  2016年   3005篇
  2015年   4660篇
  2014年   5998篇
  2013年   6589篇
  2012年   9665篇
  2011年   10171篇
  2010年   7831篇
  2009年   6776篇
  2008年   7973篇
  2007年   7835篇
  2006年   7247篇
  2005年   6477篇
  2004年   5128篇
  2003年   5201篇
  2002年   4145篇
  2001年   3157篇
  2000年   2452篇
  1999年   1641篇
  1998年   905篇
  1997年   954篇
  1996年   636篇
  1995年   559篇
  1994年   468篇
  1993年   322篇
  1992年   361篇
  1991年   306篇
  1990年   264篇
  1989年   214篇
  1988年   183篇
  1987年   164篇
  1986年   128篇
  1985年   123篇
  1984年   77篇
  1983年   57篇
  1982年   43篇
  1981年   31篇
  1980年   21篇
  1979年   41篇
  1978年   36篇
  1976年   23篇
  1973年   27篇
  1970年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
对28例严重脊柱侧凸患者行矫形手术,结果手术均获成功,松解术后1周行后路矫形内固定加植骨融合术,术后Cobb角平均为40.8°,侧弯矫正率平均为52.0%。术后随访6~30个月,均无并发症发生。提出在做好脊柱侧凸矫形手术常规护理的同时,加强患者心理、体位、呼吸、镇痛、排便等方面的舒适护理,可增强患者舒适感,为手术获得成功和患者顺利康复提供有力保障。  相似文献   
42.
Repeated administration of the antimanic drug lithium (4 mEq/kg/day for 2, 4 or 6 days, i.p.) to rats produced a progressive decline and eventual depletion of dynorphin-A (1-8) (DYN) concentration whereas Met5-enkephalin (ENK) was only marginally decreased in the neurointermediate lobe of the pituitary (NIL). Administration of a neuroleptic haloperidol neither affected ENK and DYN levels nor influenced lithium-induced changes. The study reveals that lithium produces a preferential perturbation in the dynorphin system relative to the enkephalin system. These results taken together with other evidence, indicate that dynorphin is possibly coreleased with vasopressin following lithium administration and provide a pharmacological support to the previously described colocalization and corelease of these endogenous peptides in the NIL.  相似文献   
43.
Aim: To examine the survival benefit of liver and lung resection for colorectal metastasis and the potential prognostic factors that affect patient survival. Methods: All patients who had resection of lung or liver metastasis for colorectal metastasis in Queen Elizabeth Hospital, Hong Kong from 1995 to 2004 were retrospectively reviewed. The overall and disease‐free survival was analysed, in particularly between liver and lung metastasis. All factors that may have affected the survival were entered into Cox's proportional hazards regression model to identify significant variables associated with survival. Results: At 5 years, the overall survival of patients who had resection of lung and liver metastasis was 44% and 38%, respectively; the disease‐free survival was 26% and 24%, respectively. Overall and disease‐free survival of patients with resection of lung metastasis was comparable to those with resection of liver metastasis. The differentiations of primary tumour and time to metastasis were shown to be significant prognostic factors influencing overall survival. Those patients with systemic chemotherapy after resection of colorectal metastasis demonstrated a significantly higher probability of overall survival. Conclusion: Resection of lung and liver metastases from colorectal origin was safe and both procedures improved survival. The use of chemotherapy after resection of metastasis significantly improved the overall survival.  相似文献   
44.
目的: 几乎没有研究报道妊娠高血压综合征 (妊高征 ) 患者尿蛋白对新生儿出生体重的影响, 该研究欲探讨妊高征患者不同水平尿蛋白对新生儿出生体重的影响关系。方法: 1997年 1月 ~2004年 6月期间, 住院分娩患中、重度妊高征产妇 136例, 对新生儿出生体重与各种因素进行回归分析及t检验分析。结果: 单变量回归分析尿蛋白、孕龄分别与新生儿出生体重有高度显著性关系 (P<0. 01); 尿蛋白和孕龄一起进入多元回归分析, 校正影响因素, 尿蛋白和孕龄仍然是影响新生儿出生体重显著性因素 (P<0 .01); 与妊高征尿蛋白 ( +) 比较, 尿蛋白 无显著性影响新生儿出生体重 (P>0. 05), 尿蛋白 有显著性影响新生儿出生体重 (P<0. 01)。结论: 新生儿出生体重与妊高征患者尿蛋白丢失有关, 尿蛋白 丢失将严重影响新生儿出生体重。  相似文献   
45.
目的:采用直丝弓矫治器矫治成年患者骨性AngleⅡ类2分类错牙合,以研究正畸治疗前后牙、颌硬组织变化,评价正畸矫治效果。方法:本文选择了8例AngleⅡ类2分类错牙合成年患者,男3例,女5例,年龄19~27岁,平均23.6岁。拔除双侧上颌第一双尖牙,运用直丝弓矫治器进行治疗,拍摄治疗前后X线头颅定位侧位片,进行治疗前后的X线头影测量研究。结果:治疗后SNA角减小,ANB角减小,U1-SN角增大,L1-MP角增大,U1-L1角减小。上颌切牙牙根及上颌基骨明显腭向移动,减小了上颌骨突度;下颌切牙牙冠明显唇向倾斜,代偿了下颌骨后缩。结论:骨性AngleⅡ类2分类错牙合患者经过上颌拔牙矫治后,面形有所改善,取得了理想的矫治效果。  相似文献   
46.
Hematopoietic effects in mice exposed to arsine gas   总被引:1,自引:0,他引:1  
Arsine gas is a potent hemolytic agent. Concern about semiconductor workers prompted an in-depth study of arsine at the National Institute of Environmental Health Sciences to determine the hematopoietic effects of prolonged exposure to this gas. Female B6C3F1 mice were exposed by inhalation to 0, 0.5, 2.5, and 5 ppm arsine, 6 hr/day for 14 days. Body weights of exposed mice were comparable to those of controls, but a marked, concentration-related splenomegaly was observed. Higher level arsine exposure produced statistically significant decreases in red blood cells, hematocrit and hemoglobin, with increases in white blood cell counts and mean corpuscular volume of red blood cells. Erythropoiesis as measured by quantitation of erythroid precursors in culture revealed a marrow reduction of colony-forming unit erythroids/femur cells for all treated groups on Day 3 postexposure and only at the 5 ppm dose group on 24 days postexposure, while splenic erythropoiesis increased at higher concentrations of arsine. There was no alteration in bone marrow cellularity and a less significant effect on granulocyte-macrophage progenitors. A 12-week study of arsine at 0, 0.025, 0.5, and 2.5 ppm (6 hr/day) by inhalation showed similar effects on hematopoiesis in mice. In conclusion, arsine exposure at low concentrations produces a stress on the hematopoietic system characterized by hemolysis, which persists for a prolonged period following exposure.  相似文献   
47.
目的 了解、观察葡立胶囊与抗骨增生胶囊联用治疗颈椎病对血清SOD含量及疼痛功能评分的影响。方法 对一组神经根型颈椎病患者,用葡立胶囊与抗骨增生胶囊联合应用治疗3个月,测定血清SOD含量及疼痛功能评分变化。结果 颈椎病患者治疗组血清SOD含量与治疗前相比明显升高,疼痛功能评分治疗前相比明显降低。结论 葡立胶囊与抗骨增生胶囊联合应用可明显缓解症状,提高血清SOD活力,延缓颈椎间盘退变,对治疗颈椎病有明显疗效。  相似文献   
48.
OBJECTIVE: To determine the location in soft tissues of the calcifications, similar to calcified carotid atheromas, that can be observed radiographically in the cervical region in panoramic radiographs. STUDY DESIGN: In each anatomic cadaver specimen preserved in formol, consisting of the head and neck, radiopaque spheres (made from gutta-percha) were positioned in anatomic structures of the cervical region that can be sites of calcification. For each anatomic structure marked in this way, panoramic radiography was performed, consisting of 17 radiographs. The images obtained were analyzed by 24 examiners who indicated which radiographs, in their opinion, presented the radiopaque reference projected in the region of bifurcation of the carotid artery. Analysis of 2 proportions from agreement and disagreement was used to determine radiopacities that could be confused in panoramic radiographs with calcified atheromas in the carotid artery. RESULTS: The results showed that 75% (18) of the examiners correctly indicated the reference in the bifurcation of the carotid artery and 79.2% (19) indicated a triticeous cartilage as calcified atheroma of the carotid artery. CONCLUSIONS: Calcified atheromas of the carotid artery are not the only features that can produce radiopaque images lateral to the panoramic radiograph; the presence of calcification in the triticeous cartilage also can induce an erroneous diagnosis of calcified carotid atheroma.  相似文献   
49.
抗生素联合非那雄胺治疗血精症的临床观察   总被引:1,自引:0,他引:1  
目的探讨及评价抗生素联合非那雄胺选择性治疗炎症性血精症的有效性。方法选择炎症性血精症50例,随机分2组;其中28例联合用药组采用抗生素联合非那雄胺治疗3个月,22例对照组仅用抗生素治疗3个月。结果联合用药组26例血精消失(26/28,92.9%),对照组15例血精消失(15/22,68.2%),两组比较差异有显著性。对照组中7例血精复发,加用非那雄胺治疗3个月后,5例血精消失(5/7,71.4%)。结论血精症主要是下尿路生殖道的炎症,尤其是精囊和前列腺炎引起,联合抗生素和非那雄胺治疗是治疗炎症性血精症的有效方法。  相似文献   
50.
目的探讨自发性高血压大鼠颈动脉中抑癌基因P53和原癌基因c-jun、c-fos、c-myc mRNA的表达.方法用逆转录聚合酶链式反应检测两种基因的表达水平.正常雄性大鼠作为对照组.结果 SHR颈动脉中,抑癌基因P53和原癌基因c-jun、c-fos、c-myc均有高表达,较WKY差异有显著性(P<0.05).结论自发性高血压大鼠颈动脉组织中抑癌基因P53和原癌基因c-jun、c-fos、c-myc均有高表达,癌基因的活化可能与自发性高血压大鼠颈动脉血管重构有关.  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