全文获取类型
收费全文 | 7166篇 |
免费 | 698篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 121篇 |
儿科学 | 241篇 |
妇产科学 | 197篇 |
基础医学 | 971篇 |
口腔科学 | 194篇 |
临床医学 | 691篇 |
内科学 | 1357篇 |
皮肤病学 | 219篇 |
神经病学 | 460篇 |
特种医学 | 318篇 |
外科学 | 744篇 |
综合类 | 76篇 |
一般理论 | 2篇 |
预防医学 | 936篇 |
眼科学 | 155篇 |
药学 | 520篇 |
中国医学 | 11篇 |
肿瘤学 | 659篇 |
出版年
2022年 | 47篇 |
2021年 | 95篇 |
2020年 | 76篇 |
2019年 | 123篇 |
2018年 | 130篇 |
2017年 | 109篇 |
2016年 | 137篇 |
2015年 | 154篇 |
2014年 | 173篇 |
2013年 | 221篇 |
2012年 | 343篇 |
2011年 | 293篇 |
2010年 | 204篇 |
2009年 | 186篇 |
2008年 | 307篇 |
2007年 | 331篇 |
2006年 | 346篇 |
2005年 | 333篇 |
2004年 | 285篇 |
2003年 | 277篇 |
2002年 | 247篇 |
2001年 | 219篇 |
2000年 | 233篇 |
1999年 | 206篇 |
1998年 | 124篇 |
1997年 | 126篇 |
1996年 | 99篇 |
1995年 | 102篇 |
1994年 | 83篇 |
1993年 | 78篇 |
1992年 | 135篇 |
1991年 | 171篇 |
1990年 | 162篇 |
1989年 | 156篇 |
1988年 | 177篇 |
1987年 | 135篇 |
1986年 | 120篇 |
1985年 | 119篇 |
1984年 | 104篇 |
1983年 | 67篇 |
1982年 | 53篇 |
1981年 | 66篇 |
1979年 | 79篇 |
1978年 | 56篇 |
1977年 | 55篇 |
1976年 | 52篇 |
1975年 | 63篇 |
1974年 | 55篇 |
1973年 | 52篇 |
1972年 | 44篇 |
排序方式: 共有7872条查询结果,搜索用时 15 毫秒
21.
J Kantor K Irvine S Abrams P Snoy R Olsen J Greiner H Kaufman D Eggensperger J Schlom 《Cancer research》1992,52(24):6917-6925
We have previously reported the development of a recombinant vaccinia virus vaccine expressing the human carcinoembryonic antigen (CEA) gene, designated rV(NYC)-CEA. This construct has been shown to elicit specific anti-CEA immune responses and an antitumor effect in a murine tumor model. In the studies reported here, the safety and immunogenicity of this recombinant vaccinia virus were evaluated in a rhesus monkey model. Human CEA is a M(r) 180,000 glycoprotein expressed in approximately 90% of gastrointestinal carcinomas and in some breast and non-small cell lung carcinomas. This family also includes normal cross-reacting antigen (NCA). Rhesus monkeys, like humans, have some NCA on the surface of their granulocytes. Eight monkeys were immunized 3 or 4 times by skin scarification with the recombinant CEA vaccine and four monkeys received wild-type vaccinia virus as control. After three vaccinations, all rV(NYC)-CEA-vaccinated animals exhibited a strong anti-CEA antibody response as measured by enzyme-linked immunosorbent assay. The functional ability of these antibodies to mediate lysis of a CEA-bearing tumor cell was demonstrated using human effector cells. This response could be enhanced by interleukin 2. Cellular immunity to CEA was measured by delayed-type hypersensitivity upon intradermal challenge with purified CEA. Only those animals receiving the recombinant vaccine displayed significant anti-CEA responses. Furthermore, peripheral blood mononuclear cells from immunized monkeys were found to proliferate in response to CEA stimulation. All vaccinated monkeys developed local skin irritation at the site of the vaccination, regional lymphadenopathy, and low-grade fevers after immunization. Following immunization with rV(NYC)-CEA, the response was consistent with the usual constitutional symptoms seen with human smallpox virus immunization. Blood counts, differentials, and hepatic and renal chemistries remained normal in all animals throughout the study and for up to 1 year following the primary vaccination. No evidence of immunological cross-reactivity to NCA was found by either a fall in the granulocyte count or analyses for anti-NCA antibodies. Thus, the rV(NYC)-CEA vaccine appears to be safe in rhesus monkeys. The administration of a CEA recombinant vaccine to rhesus monkeys induces both a humoral and a cell-mediated immune response directed against human CEA. 相似文献
22.
D L Goad C M Davis P Liem C C Fuselier J R McCormack K M Olsen 《The Journal of clinical psychiatry》1991,52(8):342-345
BACKGROUND: Currently there is no regimen for managing the inappropriate behavior seen in Alzheimer's disease that does not cause significant patient sedation. Preliminary evidence suggests selegiline may be effective in behavioral modification without the adverse effects observed with other regimens. The purpose of this study was to document the efficacy of selegiline in Alzheimer's patients with behavior problems. METHOD: Eight Alzheimer's patients (6 women and 2 men) ranging in age from 50 to 82 years (mean +/- SD = 74.0 +/- 10.5) were enrolled in this single-blind study. Patients received selegiline 10 mg each day for 8 weeks. Prior to drug administration and at the end of Weeks 1, 2, 4, 6, and 8, patients were evaluated for behavior (BEHAVEAD), cognitive function (Mini-Mental State Examination), and caregiver stress (Caregiver Burden Scale). RESULTS: Of eight enrolled patients, five were available for analysis. No statistically significant differences were found between mean baseline and mean 8-week scores for any of the three tests. However, clinical significance was noted by improvement in cognition (orientation and recall), caregiver stress, and behavior. Behavior was noted to improve in the areas of paranoid and delusional ideation, hallucinations, activity disturbances, anxiety, and phobias. CONCLUSION: These data suggest that some Alzheimer's patients with behavior problems may benefit from selegiline therapy. 相似文献
23.
Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study. 相似文献
24.
This study investigates whether the cerebral blood flow reduction occurring in attacks of classic migraine is sufficient to cause neurologic deficits. Regional cerebral blood flow measured with the xenon 133 intracarotid injection technique was analyzed in 11 patients in whom a low-flow area developed during attacks of classic migraine. When measured with this technique, regional cerebral blood flow in focal low-flow areas will be overestimated because of the effect of scattered radiation (Compton scatter) on the recordings. In this study, this effect was particularly taken into account when evaluating the degree of blood flow reduction. During attacks of classic migraine, cerebral blood flow reductions averaging 52% were observed focally in the 11 patients. Cerebral blood flow levels known to be insufficient for normal cortical function (less than 16 to 23 mL/100 g/min) were measured in seven patients during the attacks. This was probably also the case in the remaining four patients, but the effect of scattered radiation made a reliable evaluation of blood flow impossible. It is concluded that the blood flow reduction that occurs during attacks of classic migraine is sufficient to cause ischemia and neurologic deficits. Hence, this study suggests a vascular origin of the prodromal neurologic deficits that may accompany attacks of classic migraine. 相似文献
25.
26.
27.
Mycoplasma pneumoniae Induces Chronic Respiratory Infection, Airway Hyperreactivity, and Pulmonary Inflammation: a Murine Model of Infection-Associated Chronic Reactive Airway Disease 总被引:9,自引:0,他引:9
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Robert D. Hardy Hasan S. Jafri Kurt Olsen Jeanine Hatfield Janie Iglehart Beverly B. Rogers Padma Patel Gail Cassell George H. McCracken Octavio Ramilo 《Infection and immunity》2002,70(2):649-654
Because chronic Mycoplasma pneumoniae respiratory infection is hypothesized to play a role in asthma, the potential of M. pneumoniae to establish chronic respiratory infection with associated pulmonary disease was investigated in a murine model. BALB/c mice were intranasally inoculated once with M. pneumoniae and examined at 109, 150, 245, 368, and 530 days postinoculation. M. pneumoniae was detected in bronchoalveolar lavage fluid by culture or PCR in 70 and 22% of mice at 109 and 530 days postinoculation, respectively. Lung histopathology was normal up to 368 days postinoculation. At 530 days, however, 78% of the mice inoculated with M. pneumoniae demonstrated abnormal histopathology characterized by peribronchial and perivascular mononuclear infiltrates. A mean histopathologic score (HPS) at 530 days of 5.1 was significantly greater (P < 0.01) than that for controls (HPS score of 0). Serum anti-M. pneumoniae immunoglobulin G was detectable in all of the mice inoculated with M. pneumoniae and was inversely correlated with HPS (r = -0.95, P = 0.01) at 530 days postinoculation. Unrestrained whole-body plethysmography measurement of enhanced pause revealed significantly elevated airway methacholine reactivity in M. pneumoniae-inoculated mice compared with that in controls at 245 days (P = 0.03) and increased airway obstruction at 530 days (P = 0.01). Murine M. pneumoniae respiratory infection can lead to chronic pulmonary disease characterized by airway hyperreactivity, airway obstruction, and histologic inflammation. 相似文献
28.
N Olsen 《Scandinavian journal of work, environment & health》1987,13(4):309-312
A selective review on the attack of Raynaud's phenomenon in primary Raynaud's phenomenon and vibration-induced white finger is presented with special reference to the location of the primary vasospasm, the nature of the dominant pathophysiological mechanism, and the anatomic location of the abnormal link in this mechanism. It is suggested that the primary vasospasm is a total closure of the main digital arteries, that the arterial spasm is mainly mediated through an exaggerated central sympathetic reflex mechanism, and that the abnormal link in this reflex arch could be the smooth muscle cells of the digital arteries. Other anatomic locations of the abnormal link can however not be excluded as yet. 相似文献
29.
Summary Total parotidectomy causes a significant postoperative concave deformity in the retromandibular, preauricular, and infra-auricular regions of the face; many patients are concerned about this defect. Frey's syndrome (gustatory sweating) is also a well-recognized postoperative entity following parotid surgery. The incidence of Frey's syndrome ranges from 10–90%, depending on the type and complexity of the investigation used to diagnose it [5, 11]. Numerous methods have been described to correct these problems. Patients requiring total parotidectomy were recently offered the option of immediate reconstruction of the contour defect with microvascular transfer of a tailored gracilis muscle flap. Four patients are included in this preliminary series; all are extremely satisfied with the postoperative result. The defect following total parotidectomy can be reconstructed immediately with gratifying cosmetic results, a hidden donor site scar, and to date no operative morbidity. 相似文献
30.