全文获取类型
收费全文 | 48735篇 |
免费 | 2194篇 |
国内免费 | 3509篇 |
专业分类
耳鼻咽喉 | 500篇 |
儿科学 | 702篇 |
妇产科学 | 921篇 |
基础医学 | 7557篇 |
口腔科学 | 573篇 |
临床医学 | 3432篇 |
内科学 | 9303篇 |
皮肤病学 | 491篇 |
神经病学 | 3269篇 |
特种医学 | 1083篇 |
外国民族医学 | 7篇 |
外科学 | 5071篇 |
综合类 | 5123篇 |
现状与发展 | 55篇 |
一般理论 | 17篇 |
预防医学 | 2538篇 |
眼科学 | 1936篇 |
药学 | 5127篇 |
4篇 | |
中国医学 | 1151篇 |
肿瘤学 | 5578篇 |
出版年
2024年 | 107篇 |
2023年 | 452篇 |
2022年 | 314篇 |
2021年 | 249篇 |
2020年 | 179篇 |
2019年 | 124篇 |
2018年 | 153篇 |
2017年 | 81篇 |
2016年 | 141篇 |
2015年 | 202篇 |
2014年 | 483篇 |
2013年 | 230篇 |
2012年 | 8464篇 |
2011年 | 9139篇 |
2010年 | 1579篇 |
2009年 | 672篇 |
2008年 | 4975篇 |
2007年 | 4987篇 |
2006年 | 4497篇 |
2005年 | 3964篇 |
2004年 | 3313篇 |
2003年 | 2940篇 |
2002年 | 2215篇 |
2001年 | 1330篇 |
2000年 | 1710篇 |
1999年 | 861篇 |
1998年 | 311篇 |
1997年 | 88篇 |
1996年 | 67篇 |
1995年 | 72篇 |
1994年 | 51篇 |
1993年 | 39篇 |
1992年 | 22篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 47篇 |
1988年 | 35篇 |
1987年 | 29篇 |
1986年 | 18篇 |
1985年 | 21篇 |
1984年 | 37篇 |
1983年 | 26篇 |
1982年 | 23篇 |
1981年 | 19篇 |
1980年 | 24篇 |
1979年 | 14篇 |
1965年 | 13篇 |
1964年 | 11篇 |
1963年 | 9篇 |
1962年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Lycium barbarum(LB)is a traditional Chinese medicine that has been demonstrated to exhibit a wide variety of biological functions,such as antioxidation,neuroprotection,and immune modulation.One of the main mechanisms of Alzheimer’s disease is that microglia activated by amyloid beta(Aβ)transform from the resting state to an M1 state and release pro-inflammatory cytokines to the surrounding environment.In the present study,immortalized microglial cells were pretreated with L.barbarum extract for 1 hour and then treated with oligomeric Aβfor 23 hours.The results showed that LB extract significantly increased the survival of oligomeric Aβ-induced microglial cells,downregulated the expression of M1 pro-inflammatory markers(inducible nitric oxide synthase,tumor necrosis factorα,interleukin-6,and interleukin-1β),and upregulated the expression of M2 anti-inflammatory markers(arginase-1,chitinase-like protein 3,and interleukin-4).LB extract also inhibited the oligomeric Aβ-induced secretion of tumor necrosis factorα,interleukin-6,and interleukin-1βin microglial cells.The results of in vitro cytological experiments suggest that,in microglial cells,LB extract can inhibit oligomeric Aβ-induced M1 polarization and concomitant inflammatory reactions,and promote M2 polarization. 相似文献
2.
Kui Li Jiawen Wang Shengxiong Liu Sen Su Chenjian Feng Xiaoxiang Fan Zhiyong Yin 《中华创伤杂志(英文版)》2015,18(2):65-73
Objective: To study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.
Methods: In this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.
Results: In Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.
Conclusions: The results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism. 相似文献
3.
4.
BACKGROUND: Ankle brachial index(ABI)is widely involved in researches and clinical application of peripheral vascular injury of patients with diabetes (DM);however ,the application in cerebral infarction(CI)is rare.OBJECTIVE: To investigate the possible risk factor of cerebral infarction plus peripheral arterial disease(PAD),compare metabolic characteristics of patients who having CI plus PAD or only having CI,and understand the significance of ABI on screening and diagnosing CI plus PAD of lower limb.DESIGN: Contrast observation based on CI patients.SETTING: Deparment of Neurology,Nanxishan Hospital of Guangxi Zhang Autonomous Region.PARTICIPANTS:A total of 124 CI patients were selected from Department of Neurology.Nanxishan Hospital of Guangxi Zhuang Autonomous Region from July 2005 to April 2006,including 72 males and 52 females aged from 45 to 88 years.All patients met the diagnostic criteria of cerebrovascular disease established by National Academic Conference of Cerebrovascular Diseases in 1995 and determined as cerebral infarction with MRI or CT examination.All patients provided informed consent.There were 46 cases(37.2%)with CI plus PAD and 78 cases(62.8%)only with CI.METHODS: Blood pressure of bilateral ankles and upper extremities was measured at plain clinostatism with DINAMAP blood pressure monitor(GE Company).The ratio between average systolic pressure of lateral ankle and average systolic pressure of both upper extremities was regarded as ABI.The normal ABI was equal to or more than 0.9.If ABI<0.9 occurred at one side,patients were diagnosed as PAD.On the second morning after hospitalization,blood was collected to measure fasting blood glucose(FBG),2-hour postprandial blood glucose(PBG2h),glycosylated hemoglobin(HbAlc),triglycerides(TG),total cholesterol(TC),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C).Among them,blood glucose.lipid and other biochemical markers were measured with enzyme chemistry assay and HbA1c was measured with HbA1c meter based on high liquid phase.Measurement data and enumeration data were compared with t test and Chi-square test.and multiple factors were deat with Logistic regression analysis and multivariate linear regression analysis.MAIN OUTCOME MEASURES: Results of correlation between ABI and metabolic markers with multivariate linear regression analysis;risk factors of CI plus PAD with Logistic regression analysis;comparisons of metabolic markers between PAD and non-PAD patients.RESULTS:All 124 patients with acute CI were involved in the final analysis.①Comparisons of metabolic markers:Levels of serum LDL-C and uric acid(UA)were higher of PAD patients than those of non-PAD patients(t=2.051 9,3.339 1,P<0.05);however,there were no significant differences among other metabolic markers(P>0.05).②Results of multivariate linear regression analysis:PBG2h,LDL.C and UA were obvious correlation with ABI of posterior tibial artery of lower limb and dorsal pedis artery rpartial regression coefficient:-0.231 to-1.010,P<0.05).③Risk factors of CI plus PAD with Logistic regression analysis:Age.Smoking history,sum of CI focus(≥3)and LDL-C were independent risk factor of CI plus PAD(OR=1.524-5.422,P<0.05-0.01 ).CONCLUSION:①Levels of serum LDL-C and UA of patients with CI plus PAD are high.②ABI of lower limbs is correlation with PBG2h,LDL-C and UA.In addition,measuring ABI is beneficial for early diagnosing PAD of lower limbs of patients who have poorly controlled blood glucose,abnormal lipid and poor renal function.③Age,LDL-C and sum of CI focus(≥3)are independent risk factors of CI plus PAD.It is of significance for screening non-PAD patients to evaluate risk degrees and prognosis and select therapeutic methods based on ABI measurement. 相似文献
5.
6.
Objective: To observe the clinical effect of Neiyifang (NYF) in treating endometriosis and to explore its therapeutic mechanism through
observing its influence on plasma β-endorphin (β-EP) in different menstrual stages and levels of prostaglandins (PGs) in menstruation.Methods:NYF was administered to 104 patients with endometriosis one dose daily with 3 successive menstrual cycles as one therapeutic
course. Peripheral blood β-EP level in follicular, luteal and menstrual stages, as well as PGF2α, PGE2, thromboxane B2 and 6-keto-PGFl α levels in menstrual stage were detected by RIA, and controlled with those in 15 healthy persons.Results: (1) The total effective rate of NYF was 81.3% and it showed significant effect in improving patients’ clinical symptoms
and physical signs; (2) In menstrual stage, the levels of β-EP, 6-keto-PGFα/ TXB2 were lower(P <0.05) and levels of PGF2α, PGE2, TXB2 and 6-keto-PGF1α were higher (P< 0. 05) in patients than those in control, and the higher the level of PGE2, the severer the menalgia, (3) NYF could increase levels of β-EP, 6-keto-PGF1α, and reduce levels of PGF2α, PGE2α in menstrual stage of patients (all P<0.05).Conclusion: (1) NYF has good clinical effect in treating endometriosis; (2) Patients’ symptom of menalgia is closely related with the
excessive high levels of PGF2α and PGE2, PGI2/TXA2 ratio disturbance, and excessive low level of β-EP; (3) NYF could significantly decrease the PGE2, PGF1α levels, increase the 6-keto-PGF1α/TXB2 ratio and the level of β-EP, so as to alleviate the menalgia in patients with endometriosis.
This item was supported by National Funds of Natural Sciences(No. 30070942) 相似文献
7.
神经生长因子(NGF)是神经元的发育分化所必需的因子,推测神经母细胞瘤可能为神经母细胞分化过程中受到阻滞的结果。本研究以18个人神经母细胞瘤细胞系为基本材料研究了NGF诱导分化规律结果发现:NGF诱导瘤细胞分化与NGF受体的有无,N-myc癌基因的扩增或过度表达及瘤细胞的形态表达有密切关系。经用Northernblot及原位杂交研究表明,神经母细胞瘤系中有C-myC表达者则多无N-myC的表达,反之亦然,在分化的细胞中C-myc瘤基因的表达明显降低,提示NGF可能通过抑制C-myc的表达而促进癌细胞的分化;不同细胞类型代表着不同的分… 相似文献
8.
国内医院病理科的现状 总被引:8,自引:1,他引:7
国内病理学科是 2 0世纪 2 0年代由病理界前辈胡正详、梁伯强、谷镜研、候宝璋和林振纲等教授从国外引进的。他们从西方国家回国后在各自的教学单位培植了数量不等承前启后的病理工作者 ,除病理教学外他们还开展了尸检和活检工作。新中国成立后 ,医学院和医院的数量得到大幅度增长 ,国内病理学才有了较大的发展 ,病理医生和技术人员成倍增多 ,病理学的教学、科研和临床工作得到了较好的发展 ,但当时只限于大城市的医学院校和大医院。改革开放后国内病理界得到了长足的发展 ,到 2 0世纪末全国各地包括边远地区的医学院校和医院都已有了病理科… 相似文献
9.
Xiangyu Piao Changkai Sun Zhe Jin Jing Yu Xiaodan Chang Xin Tang Hongmei Liu Peiyang Zhou 《中国神经再生研究》2007,2(9):540-543
BACKGROUND: The cerebral ischemia and ischemia/reperfusion animal models are used to simulate the human cerebrovascular diseases is one of the popular topics of neurological science recently. To study the pathophysiology, pathogenesis, prophylaxis and treatment of ischemic cerebrovascular diseases and to establish the ideal animal model that is the most similar to the human cerebral ischemia, are the topics that the people generally cared about.
OBJECTIVE: To evaluate the effects of aerocyst-blocking bilateral ascending pharyngeal artery on the establishment of cerebral ischemia models by using digital subtraction angiography (DSA), magnetic resonance diffusion-weighted imaging (DWI) and magnetic resonance perfusion-weighted imaging (PWI).
DESIGN: Repetitive measure animal experiment.
SETTING: Zhongshan Hospital Affiliated to Dalian University.
MATERIALS: The experiment was carried out in the Animal Laboratory (Provincial Laboratory), Zhongshan Hospital of Dalian Univeristy from January to May 2006. A total of 14 domestic piglets, of 6 months old, weighing 12–15 kg, of either gender, were selected from Animal Experimental Center, Dalian University. Multistar T.O.P digital subtraction angiography machine was provided by Siemens Company, German.
METHODS: Aerocyst-blocking bilateral ascending pharyngeal artery was used to establish cerebral ischemia models. And then, Multistar T.O.P. DSA was used for imaging of cerebral vessels before blocking, during blocking and at 0.5 and 2 hours after ischemia perfusion. GE Signa 1.5 T supraconduction magnetic resonance imaging was used for DWI examination; in addition, PWI was used based on focal sites and areas. Otherwise, magnetic resonance imaging (MRI) was used to detect signal changes of T1WI and T2WI in ischemic areas.
MAIN OUTCOME MEASURES: Analytic results of DSA, DWI, PWI and MRI.
RESULTS: All 14 experimental piglets were involved in the final analysis. ① DSA: The blood flow of bilateral ascending pharyngeal arteries and its branch were blocked at blocking phase, which restored 0.5 and 2 hours after reperfusion. ② DWI and PWI: There were no observable abnormalities in PWI and DWI at pre-blocking. Abnormal increased signals were found on both DWI and PWI at during and post-blocking. There were reduction in ADC and rCBF and delay in rTTP at all time points except pre-blocking. ③ MRI: There were no abnormal signals observable at any time of pre- and post-blocking in T1WI and T2WI.
CONCLUSION: It is feasible to establish this kind of animal experimental models, and it can simulate the ischemic state; meanwhile, the existence and extent can be showed directly by DSA, DWI, and PWI. 相似文献
10.
The purpose of the pre~ent paper is to review certain aspects of
catarrhal jaundice and arsenical jaundice and their relation to acute
yellow atrophy in connection with a case of diffuse liver degeneration
following neo-arsphenamine and mapharsen treatment with rapid fatal
termination. Such a review may serve to clarify our present position
in regard to the pathogenesis of catarrhal jaundice and arsenical
jaundice. The case is remarkable in that the liver remained Iarge to
the end in spite of the fulminating course. 相似文献