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   34611篇
  免费   3481篇
  国内免费   2521篇
耳鼻咽喉   212篇
儿科学   480篇
妇产科学   391篇
基础医学   4224篇
口腔科学   622篇
临床医学   4460篇
内科学   5423篇
皮肤病学   313篇
神经病学   1555篇
特种医学   1138篇
外国民族医学   29篇
外科学   3733篇
综合类   6009篇
现状与发展   10篇
一般理论   3篇
预防医学   2394篇
眼科学   932篇
药学   3747篇
  33篇
中国医学   2013篇
肿瘤学   2892篇
  2024年   166篇
  2023年   698篇
  2022年   1671篇
  2021年   2104篇
  2020年   1455篇
  2019年   1253篇
  2018年   1222篇
  2017年   1139篇
  2016年   1045篇
  2015年   1559篇
  2014年   1948篇
  2013年   1747篇
  2012年   2500篇
  2011年   2803篇
  2010年   1724篇
  2009年   1366篇
  2008年   1731篇
  2007年   1830篇
  2006年   1691篇
  2005年   1619篇
  2004年   1150篇
  2003年   1107篇
  2002年   969篇
  2001年   783篇
  2000年   760篇
  1999年   765篇
  1998年   447篇
  1997年   464篇
  1996年   352篇
  1995年   339篇
  1994年   326篇
  1993年   177篇
  1992年   226篇
  1991年   227篇
  1990年   236篇
  1989年   182篇
  1988年   152篇
  1987年   120篇
  1986年   123篇
  1985年   94篇
  1984年   70篇
  1983年   39篇
  1982年   28篇
  1981年   22篇
  1979年   20篇
  1977年   16篇
  1975年   14篇
  1974年   19篇
  1972年   13篇
  1969年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Objectives: To verify the validity of the recently described sciatic functional index for mice to monitor neuronal functional recovery over time using a blinded, randomized, and controlled evaluation. Study Design: Surgery was performed on the left sciatic nerves of 62 C57/BL mice after randomly assigning them to one of four surgical groups: sham surgery, sciatic nerve crush, nerve transection without repair, and nerve transection followed by epineurial suture repair. Sciatic functional indices were measured before surgery and then after surgery at 10-day intervals for 90 days, using a previously described formula. Results: Sham surgery did not affect nerve function when compared with preoperative values (P > .24). Crush surgery produced a reversible nerve injury that fully recovered after 20 days. Nerve transection without repair resulted in complete functional disability without recovery of function during the 90-day follow-up interval. When transected nerves were repaired, complete functional disability was noted at day 10, with subsequent functional recovery to 26% of function at day 30. This level of recovery persisted until the 60th postoperative day when muscle contractures resulted in progressive worsening of the index. There were statistically significant differences between the sciatic functional indices of each of the groups (P < .05). Conclusions: The previously described sciatic functional index for mice is an accurate indicator of the level of sciatic neuronal function during recovery. This index represents a method of evaluating neuronal function that may provide a better reflection of the recovery parameters that are important in clinical situations. The sciatic functional index will allow for study of sciatic nerve functional recovery in genetically engineered transgenic mice.  相似文献   
82.
Z Zhang  J Liu  X Shang  J Yang  J Chu  Z Wang  Z Yao  H Ma  Q Li  Y Wang 《中国中药杂志》1998,23(2):104-6, inside back cover
It has been proved that Rhodiola Capsules can obviously decrease the oxygen consumption of myocardium and oxygen consumption index in anesthetic dogs, decrease the coronary artery resistance, but have no marked effect on the coronary artery blood flow. The Capsules also have the function of decreasing blood presure and slowing heart rate.  相似文献   
83.
熔覆层中的颗粒相分布不仅影响材料性能,同时也是研究熔覆过程各种反应机制的主要依据。本文利用图像分析技术,定量分析了Q235钢表面Cu5%Al激光熔覆层的富铁相颗粒分布情况。发现熔覆过程中在熔池中存在熔体对流环,熔池中的对流带动颗粒运动,是决定熔覆层颗粒分布的主要因素。  相似文献   
84.
养血清脑颗粒治疗老年期痴呆的临床疗效观察   总被引:1,自引:0,他引:1  
目的:观察养血清脑颗粒对老年期痴呆的疗效。方法:治疗组老年期痴呆患者36例均应用养血清脑颗粒。详录治疗前后实验室检查数据。健康老年人34例为对照组,以其体检时所得相关指标与治疗组比较分析。结果:有效率85%,S-TC明显下降,P-SOD明显升高,P-LPO,Ht,Va降低、EET缩短。结论:养血清脑颗粒具有降脂、抗自由基损伤。改善异常血液流变,增加脑血流量等功用。对老年期痴呆防治有较好效果。  相似文献   
85.
The mechanisms associated with metallothionein (MT) gene regulation are complex and poorly understood. Only a modest increase in brain MT expression levels is attained by exposure to metals, MT gene transfection, and MT gene knock-in techniques. Accordingly, in the present study, MT null astrocytes isolated from transgenic mice deficient in MT-I and MT-II genes were introduced as a zero background model of MT expression. MT protein levels were determined by western blot analysis. MT proteins in MT-I and MT-II null astrocytes were undetectable. Transient MT-I gene transfection increased the levels of foreign MT expression in MT-I and MT-II null astrocytes by 2.3-fold above basal levels in wild-type astrocytes. Intracellular Na(2)51CrO(4) efflux and D-[2,3-3H]aspartate uptake were studied as indices of acute methylmercury (MeHg) (5 microM) cytotoxicity. In MT-I and MT-II knockout astrocytes MeHg led to significant (p<0.01) increase in Na(2)51CrO(4) efflux and a significant (p<0.05) decrease in the initial rate (1 min) of D-[2, 3-3H]aspartate uptake compared to MT-I and MT-II knockout controls. Transfection of the MT-I gene in MT-I and MT-II null mice significantly (p<0.01) decreased the effect of MeHg on Na(2)51CrO(4) efflux in MT null, as well as wild-type astrocytes. MT-I gene transfection in MT-I and MT-II null astrocytes reversed the inhibitory effect of MeHg on D-[2,3-3H]aspartate uptake, such that initial rates of uptake in MT-I transfected cells in the presence and absence of MeHg (5 microM) were indistinguishable. These results demonstrate that: (1) astrocytes lacking MTs are more sensitive to MeHg than those with basal MT protein levels, (2) the MT-I gene can be overexpressed in MT-I and MT-II null astrocytes by transient MT-I gene transfection, and (3) that foreign MT expression endows astrocytes with increased resistance to MeHg.  相似文献   
86.
目的 :探讨多种肿瘤标志物对卵巢癌的诊断价值。方法 :应用化学发光法测定卵巢肿瘤、子宫内膜异位症和盆腔炎性包块的CA1 2 5、CA1 99、CA1 5 3、AFP、CEA阳性率。结果 :卵巢癌患者中 ,80 .6 0 %CA1 2 5阳性 ,92 .5 3%联合检测阳性 ,阳性率明显高于良性肿瘤、子宫内膜异位症、盆腔炎性包块患者 (P <0 .0 1 ) ;CA1 2 5与卵巢癌的临床分期及病理类型无关 ,但Ⅰ期卵巢癌患者的血清CA1 2 5值明显低于Ⅱ~Ⅳ期患者 (P <0 .0 1 )。结论 :CA1 2 5对卵巢癌的诊断有一定的价值 ,联合监测能提高卵巢癌的诊断率 ,尤其对早期卵巢癌。  相似文献   
87.
综合治疗发育性弱视243例   总被引:4,自引:7,他引:4  
目的:探讨各种类型发育性弱视治疗的疗效。方法:对243例发育性弱视患者进行包括验光配镜、遮盖治疗、红光闪烁治疗、后像疗法、精细目力训练等的综合治疗。结果:基本治愈率为56.4%,有效率为92.4%,其中轻度弱视的治愈率为81.6%,中度为41.1%,重度为24.3%;屈光不正性弱视的治愈率为62.9%,斜视性弱视为49.0%,屈光参差性弱视为43.1%,形觉剥夺性弱视为18.8%;中心注视的治愈率为65.3%,旁中心注视为20.7%;年龄≤6岁的治愈率为82.7%,年龄在7~9岁间的为49.4%,年龄≥10岁的为19.6%。结论:弱视的治疗效果与弱视程度、类型、注视性质、初诊年龄等密切相关,早期发现,早期治疗效果好。综合疗法的疗效优于单一治疗方法。  相似文献   
88.
BACKGROUND AND PURPOSE: To adapt the Taiwan version of the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire and evaluate its psychometric properties. METHODS: The DASH questionnaire was adapted through the process of translation, back-translation, and expert review. Eighty two subjects with upper extremity disorders were recruited in a medical center and 46 of these patients could be followed up to assess retest reliability in less than 10 days. Cronbach alpha and intraclass correlation coefficient were used to evaluate the internal consistency and test-retest reliability. Principal axis factor analysis was performed to assess the factor-construct validity, while concurrent validity was tested with the Medical Outcomes Study Short Form-36 (SF-36) Taiwan version questionnaire. RESULTS: The internal consistency of the Taiwan version of the DASH questionnaire was high (Cronbach alpha = 0.96) and the test-retest reliability was satisfactory (intraclass correlation coefficient = 0.9). Principal axis factor analysis confirmed the 1-factor model. The Pearson correlation coefficients of the DASH questionnaire to the SF-36 showed a correlation with physical component summary scores rather than mental component summary scores. Bodily pain, physical function and role-physical scores among the SF-36 subscales were most significantly correlated with DASH disability/symptom scores. CONCLUSION: The Taiwan version of the DASH questionnaire is a valid and reliable measure of health status for patients with upper-extremity disorders.  相似文献   
89.
姚元波 《基层医学论坛》2006,10(18):773-774
目的探讨心脏直视手术后神经系统并发症发生的原因、预防措施及救治体会。方法回顾性分析心脏直视手术后18例神经系统并发症的临床表现及诊治过程。结果18例中,一过性的神经精神功能紊乱13例,中枢神经系统功能障碍4例;经治疗,1例死亡,17例患者均痊愈出院,随访中,有2例留下后遗症。结论引发体外循环心脏直视手术后神经系统并发症的主要原因是脑栓塞和脑氧供需失衡、年龄偏大、原有神经系统疾病和糖尿病、术前心功能差、大动脉病变及体外循环时间长等,治疗方法以支持性为主,消除脑组织本身所发生破坏性反应,此外,可以通过改进各项技术措施加以预防。  相似文献   
90.
Objective: To study the effects of kadsurenone on inflammatory mediators Platelet-activating factor (PAF), tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) in rat model of acute pancreatitis(AP). Methods: SD male rats (104) were randomly divided into sham group (n = 24), AP group (n = 40) and kadsurenone group (n = 40). The rats were killed 3, 6, 12 and 24 hours after operation. The serum level of PAF, TNF-α and IL-6 was measured. Results: The serum level of PAF, TNF-α and IL-6 of AP group was significantly increased(P 〈 0.01 )compared with control group. The serum level of TNF-α got to a peak 6 hours after operation, and the serum IL-6 getting to a peak 12 hours after operation in AP group. After kadsurenone was administered to AP rats, pancreas and lung myeloperoxidase (MPO), serum amylase activity was reduced. Histology showed a trend toward improvement. The serum level of PAF, TNF-α and IL-6 was significantly decreased (P 〈 0.05). Conclusion. Kadsurenone can reduce the severity of systemic inflammation in rats with AP and relieve the damage of the pancreas and lung in AP rats. These results suggested that kadsurenone may be useful in the treatment of acute pancreatitis.  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