全文获取类型
收费全文 | 31736篇 |
免费 | 2674篇 |
国内免费 | 854篇 |
专业分类
耳鼻咽喉 | 852篇 |
儿科学 | 642篇 |
妇产科学 | 467篇 |
基础医学 | 5495篇 |
口腔科学 | 417篇 |
临床医学 | 2448篇 |
内科学 | 5169篇 |
皮肤病学 | 312篇 |
神经病学 | 3117篇 |
特种医学 | 807篇 |
外国民族医学 | 4篇 |
外科学 | 2089篇 |
综合类 | 2957篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 2326篇 |
眼科学 | 442篇 |
药学 | 3620篇 |
14篇 | |
中国医学 | 1638篇 |
肿瘤学 | 2445篇 |
出版年
2024年 | 83篇 |
2023年 | 579篇 |
2022年 | 952篇 |
2021年 | 1532篇 |
2020年 | 1354篇 |
2019年 | 1169篇 |
2018年 | 1131篇 |
2017年 | 1191篇 |
2016年 | 1240篇 |
2015年 | 1306篇 |
2014年 | 2042篇 |
2013年 | 2682篇 |
2012年 | 1743篇 |
2011年 | 1866篇 |
2010年 | 1432篇 |
2009年 | 1493篇 |
2008年 | 1396篇 |
2007年 | 1286篇 |
2006年 | 1218篇 |
2005年 | 961篇 |
2004年 | 879篇 |
2003年 | 761篇 |
2002年 | 639篇 |
2001年 | 540篇 |
2000年 | 444篇 |
1999年 | 419篇 |
1998年 | 371篇 |
1997年 | 336篇 |
1996年 | 289篇 |
1995年 | 312篇 |
1994年 | 279篇 |
1993年 | 240篇 |
1992年 | 245篇 |
1991年 | 240篇 |
1990年 | 184篇 |
1989年 | 184篇 |
1988年 | 165篇 |
1987年 | 164篇 |
1986年 | 167篇 |
1985年 | 250篇 |
1984年 | 247篇 |
1983年 | 151篇 |
1982年 | 206篇 |
1981年 | 149篇 |
1980年 | 133篇 |
1979年 | 143篇 |
1978年 | 81篇 |
1977年 | 70篇 |
1976年 | 71篇 |
1975年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
Response rates,duration of response,and dose response effects in phase I studies of antineoplastics 总被引:4,自引:0,他引:4
Summary Over a period of 14 years, 7,960 patients were treated in 228 phase I trials. In these patients, there were 75 complete and 432 partial responses for an overall objective response rate of 6%. Complete responses lasted a median of six months (range 1–18), while partial responses lasted a median of three months (range 1–17). Of note is that no drug has made it to the market which has not had a response in phase I trials. Responses were noted in very diverse histologic types of tumors. Although there were responses at doses which were as low as 3–5% of the recommended dose for phase II trials, the majority of responses did occur at 80–120% of the dose recommended for phase II trials. Although the response rate in phase I trials is indeed low, responses do occur. This response rate information should help the clinician provide facts for the patient considering a phase I trial with new anticancer agents. These findings also emphasize that although phase I trials are characteristically dose-finding studies, if no responses are noted in phase I studies, it is unlikely the drug will be used routinely in the clinic. 相似文献
72.
Yuhei Okubo Junji Yonese Satoru Kawakami Sinya Yamamoto Yoshinobu Komai Hideki Takeshita Yuichi Ishikawa Iwao Fukui 《International journal of urology》2007,14(9):854-855
Renal cell carcinoma (RCC) causes many kinds of symptoms such as hypercalcemia, hypertension, polycythemia and fever. Here we describe a rare case of RCC presenting with a persistent cough. After radical nephrectomy, the obstinate cough disappeared. When the tumor recurred locally, the cough also recurred. Furthermore, the cough disappeared completely again after the removal of the recurrent tumor. Although all the clinical findings suggested that the RCC caused the cough, we could not identify a specific humoral substance responsible for the cough. 相似文献
73.
A simulation study of three sequential methods for the comparison of two treatment groups when the response criterion is censored 总被引:1,自引:0,他引:1
Three recent sequential methods, group sequential analysis (GSA), the sequential probability ratio test (SPRT) and the triangular test (TT) are well suited to randomized clinical trials with a censored response criterion, as they do not require matched pairs of patients. We undertook a simulation study to investigate their statistical properties and to compare these three methods with the fixed-sample design. Our results suggest that the three methods have the expected statistical properties for size and power; they allow an important reduction of the average number of events before stopping, except with GSA when there is no treatment difference; the triangular test (closed design) appears the optimal design, as the variance of the number of events is smaller than with the sequential probability ratio test (open design) and analysis after every twenty new events does not alter the statistical properties of these sequential methods and enhances their usefulness. 相似文献
74.
Summary A double-blind, placebo-controlled study has been made of the analgesic and respiratory effects of constant rate infusions
of meptazinol and morphine in 30 patients after abdominal surgery.
Group I received meptazinol, loading dose 50 mg followed by i.v. infusion 0.5 mg · kg−1 · h−1, Group II received morphine, loading dose 5 mg and then an infusion of 0.05 mg · kg−1 · h−1, and Group III received saline.
After recovery from inhalation anaesthesia (without opiates or a local anaesthetic) pain relief and chemoreceptor carbon dioxide
tolerance were assessed before and at various times after starting the analgesic infusion. A similar degree of pain relief
was found after 10 min in Groups I and II, which lasted until the end of observation period (20 h). Heart rate and systolic
and diastolic blood pressures were lower in Group II than in Groups I and III, and respiratory rate fell in Groups I and II.
After 6 h arterial carbon dioxide tensions (PaCO2) became significantly higher in Group II than Group III. The maximum percentage fall in mean tidal volume (VT) and expired minute volume (0VE) from the preinjection values was significant in Groups I and II. End-tidal carbon-dioxide (PETCO2) and PaCO2 were significantly higher after 20 h of infusion in Group II compared to Group I. The slope of 0VE/PETCO2 (<S>) was increased in Group I and it was significantly reduced in Group II. Analysis of derived variables, such as the CO2 intercept (CO2I) and minute ventilation at 7 kPa (0VE7), indicated a shift to the right of the slopes in Groups I and II, initially more so in Group I.
It is concluded that constant rate infusions of meptazinol and morphine were effective in providing postoperative pain relief.
However, their effects on the central regulation of respiration were different, as meptazinol did not impair CO2 sensitivity whereas morphine did. 相似文献
75.
某些中枢神经元通过分叉轴突向两个以上核团投射。轴突分叉点的位置通常由计算轴突主干传导时间予以估测。但是,本工作用该法的4个公式计算细胞内或细胞外记录到的数据未能得到一致和可信的数值。结果提示,计算法的原理是不合理的,并至少对在细胞内或细胞外记录条件下估测轴突分叉点是不适用的。 相似文献
76.
Autonomic dysfunction is frequent in patients with multiple sclerosis (MS). The sympathetic skin response (SSR) and the R-R interval variation (RRIV) are simple electrophysiologic tests for the assessment of central and peripheral autonomic disturbances. Both tests were performed in 60 patients with clinically definite MS and 30 controls. The SSR was recorded simultaneously from both upper and both lower limbs. In all volunteers normal responses were recorded from the four limbs, but 39 patients (65%) showed abnormal responses in at least one limb. The reduction in amplitude of the response was correlated with patients' EDSS. In individual limbs, the SSR amplitude correlated with weakness, spasticity and cerebellar dysfunction, but was not sufficiently related to the deep sensory loss. The RRIV was abnormal in 48 MS patients (80%), as compared to the controls, but showed no significant relationship either to the EDSS or to the SSR. The sensitivity of SSR and RRIV is high and comparable with that of visual and somatosensory evoked potentials. 相似文献
77.
T. Nishikawa H. Kuwahara A. Tsuda M. Tanaka I. Koga Y. Uchida 《Human psychopharmacology》1990,5(4):363-368
Ceruletide, a potent analogue of cholecystokinin, was administered by injection to eight schizophrenics treated with neuroleptics. We examined the dose–response effect on microvibration (MV) recorded from the chin of these patients. After 15 min of bed rest, MV was recorded for 5 min as a control recording. Subsequently, saline or ceruletide, at a dose of either 0.4 m?g/kg or at 0.8 m?g/kg, was injected according to a Latin square design with an interval of 4 weeks for washing out the drug effect and MV was recorded for 30 min. MV data obtained were subjected to the fast Fourier transform and an average power spectrum was computed. A three-way analysis of variance for these data was performed upon dose-effect, time-effect after treatment, and band-effect of the average power spectrum. The present results were similar to previous findings which had revealed effects of ceruletide on tardive dyskinesia symptoms, namely, the effects of ceruletide on MV were different according to the subjects (three cases: facilitation followed by inhibition, three cases: inhibition, two cases: no effects). The dose-response curve of ceruletide appears to be linear in some cases and an inverted U-shape in other cases. Present findings showed small doses of systemically administered ceruletide would modify muscle tonus of schizophrenics under chronic treatment of neuroleptics, and provided further reason for the therapeutic drug of tardive dyskinesia. 相似文献
78.
热休克反应对大鼠感染性脑水肿脑组织诱生型一氧化氮合酶mRNA表达的影响 总被引:1,自引:0,他引:1
:探讨热休克反应 (HSR)对百日咳杆菌所致的大鼠感染性脑水肿诱生型一氧化氮合酶 (iNOS)mRNA表达的影响。方法 :从大鼠左侧颈内动脉注入百日咳菌液制备感染性脑水肿 (感脑 )模型 ,采用组织细胞原位杂交技术检测脑组织iNOSmRNA的表达。结果 :生理盐水组、4h感脑组及 4h热休克处理组均未见iNOSmRNA表达 ,8h ,2 4h时感染性脑水肿组均有明显的杂交信号 ,以 2 4h更为明显 ;而 8h ,2 4h热休克处理组仅有少数细胞有阳性信号。结论 :热休克反应对感染性脑水肿的保护作用可能与抑制iNOSmRNA的表达有关 相似文献
79.
Masaru Kato Rie Kobayashi Ikuo Watanabe 《Documenta ophthalmologica. Advances in ophthalmology》1993,84(1):71-81
An unusual form of scotopic electroretinogram with a bright white stimulus, which consisted of a rectangular a-wave of normal amplitude and a b-wave of supernormal amplitude, was recorded in three patients with cone dysfunction. In addition to poor visual acuity, abnormal color vision and reduced amplitude of the photopic electroretinogram, these patients showed a 2-log unit elevation of the dark-adaptation threshold. Funduscopic examination and fluorescein angiography revealed fine granular pigment disturbances at the mascula. The relationship between the response of the dark-adapted electroretinogram versus stimulus intensity was unique to these patients. The b-wave thresholds were elevated by 1 log unit. The b-waves were reduced in amplitude and markedly delayed in implicit time to dim stimuli, but supernormal in amplitude and normal in implicit time to bright stimuli.Abbreviations GMP
guanosine monophosphate 相似文献
80.
Bernhard R. Slaap Irene M. van Vliet Herman G. M. Westenberg Johan A. Den Boer 《Psychopharmacology》1996,127(1-2):353-358
Little is known about biological predictors of treatment response in panic disorder (PD). In the present study heart rate,
blood pressure, plasma cortisol and plasma MHPG were investigated at baseline in a sample of 44 PD patients as possible predictors
for nonresponse to treatment. We used a strict definition of nonresponse to find patients who did not respond at all after
12 weeks of treatment with brofaromine or fluvoxamine. Patients were considered nonresponders when they fulfilled two criteria:
they did not show a 50% reduction of agoraphobic avoidance and they still experienced panic attacks at endpoint. The variables
that differed significantly between the groups were used to predict nonresponse to drug therapy. Using this strict definition
of nonresponse, 15 patients (32.6%) were considered nonresponders. These patients were characterised by a higher plasma MHPG
concentration and a higher heart rate at baseline. These variables were subsequently used to predict nonresponse. 相似文献