全文获取类型
收费全文 | 208055篇 |
免费 | 2654篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 1595篇 |
儿科学 | 7233篇 |
妇产科学 | 3379篇 |
基础医学 | 20627篇 |
口腔科学 | 2644篇 |
临床医学 | 14605篇 |
内科学 | 38057篇 |
皮肤病学 | 1401篇 |
神经病学 | 19601篇 |
特种医学 | 10578篇 |
外国民族医学 | 1篇 |
外科学 | 33857篇 |
综合类 | 2425篇 |
一般理论 | 6篇 |
预防医学 | 19077篇 |
眼科学 | 3428篇 |
药学 | 11582篇 |
中国医学 | 692篇 |
肿瘤学 | 20059篇 |
出版年
2022年 | 247篇 |
2021年 | 578篇 |
2020年 | 339篇 |
2019年 | 438篇 |
2018年 | 22373篇 |
2017年 | 17733篇 |
2016年 | 20001篇 |
2015年 | 1436篇 |
2014年 | 1502篇 |
2013年 | 1629篇 |
2012年 | 8345篇 |
2011年 | 22344篇 |
2010年 | 19637篇 |
2009年 | 12196篇 |
2008年 | 20715篇 |
2007年 | 23101篇 |
2006年 | 1951篇 |
2005年 | 3515篇 |
2004年 | 4733篇 |
2003年 | 5600篇 |
2002年 | 3822篇 |
2001年 | 1557篇 |
2000年 | 1804篇 |
1999年 | 1416篇 |
1998年 | 654篇 |
1997年 | 575篇 |
1996年 | 443篇 |
1995年 | 398篇 |
1994年 | 394篇 |
1993年 | 336篇 |
1992年 | 1024篇 |
1991年 | 928篇 |
1990年 | 936篇 |
1989年 | 877篇 |
1988年 | 811篇 |
1987年 | 795篇 |
1986年 | 688篇 |
1985年 | 650篇 |
1984年 | 441篇 |
1983年 | 365篇 |
1982年 | 165篇 |
1979年 | 298篇 |
1978年 | 206篇 |
1977年 | 180篇 |
1974年 | 208篇 |
1973年 | 164篇 |
1971年 | 181篇 |
1970年 | 174篇 |
1969年 | 196篇 |
1968年 | 164篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Immunohistochemical and immunoelectron microscopical characterization of cerebrovascular and senile plaque amyloid in aged dogs'' brains 总被引:2,自引:0,他引:2
Tokuhiro Ishihara Toshikazu Gondo Mutsuo Takahashi Fumiya Uchino Shu-Ichi Ikeda David Allsop Kohzoh Imai 《Brain research》1991,548(1-2):196-205
Immunohistochemical and immunoelectron microscopical studies were carried out on 28 aged dogs' brains. Amyloid deposits were seen in the arteries and capillaries in the leptomeninges and in superficial areas of the cortices in 19 (67.9%) of the 28 dogs (10-22 years of age). Immunohistochemically, these amyloid deposits were reactive for anti-beta/A4 antibody. Additionally, a variable number of parenchymal deposits with diffuse beta/A4-immunoreactivity (diffuse plaques) was also noted throughout the cerebral cortex in 24/28 dogs (85.7%). However, these plaque lesions were undetectable in Congo red staining. Electron microscopically, amyloid fibrils, measuring 10 nm in width, were located mainly in the tunica media of the arteries, and in less involved vessels they tended to be present among collagen fibres in the adventitia and smooth muscle cells in the outer layer of the media. The plaque lesions appeared to contain sparse aggregations of amyloid fibrils. In immunoelectron microscopical examinations, all amyloid fibrils in both blood vessels and plaques were selectively labelled by gold particles. These findings indicate that aged dogs can provide a useful experimental model for research into the beta/A4-type of cerebral amyloidosis commonly seen in Alzheimer's disease. 相似文献
82.
Objective: To study the diagnostic value of T2^*-weighted first-pass perfusion imaging in breast tumors. Methods: We analyzed the magnetic resonance imaging (MRI) information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^*-weighted first-pass perfusion imaging. The curve's maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results: Malignant breast lesions showed higher maximal signal intensity drop rate (44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001) than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions (23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05). Conclusion: The T2^*-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis. 相似文献
83.
84.
M Shibata T Ohkubo H Takahashi T Kudo R Inoki 《Nihon yakurigaku zasshi. Folia pharmacologica Japonica》1986,88(2):101-107
Opiates and opioid peptides were administered in the order of 10(-9)-10(-6) mol peripherally, and their action on pain sensitivity was investigated by the modified formalin test which has two characteristic pain responses (the first and the second phase) in the mouse hindpaw. Opioid peptides (20-500 pmol) had dose-dependent analgesia against both first and second phases, and their action ranked dynorphin greater than [D-Ala2, Met5]-enkephalinamide greater than [Met5]-enkephalin. EKC and morphine (0.4-2.5 nmol) inhibited pain response of the first phase, but produced hyperalgesia in the second phase dose-dependently. Lidocaine hydrochloride had peripheral analgesic action, but was about 500-10000 times weaker than these substances. So, these peripheral analgesic actions have a different mechanism from that of local anesthetic action. N-methyl levallorphan which is thought to be a peripherally selective narcotic antagonist reversed these peripheral analgesic actions at the first and second phases and also prevented the hyperalgesic effects of EKC and morphine at the second phase. Naloxone reversed analgesia at only the first phase. These results suggest that an analgesic mechanism by opioids may exist at the peripheral site as well. Furthermore, it is estimated that a receptor exists which is antagonized by N-methyl levallorphan but not by naloxone and that there is a system of hyperalgesia by EKC and morphine in pain modulation. 相似文献
85.
86.
87.
The precise course and termination levels of the corticospinal tract (CST) in the cat were studied using the anterograde transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). Following injection of WGA-HRP into the pericruciate (sensorimotor) cortex on one side, we observed the precise caudal termination levels of the CST fibers in the lateral and ventral funiculi. Simultaneously, the bilateral CSTs descending through the dorsal funiculus of the spinal cord were identified. Anterogradely labeled CST fibers within the lateral and ventral funiculi were observed bilaterally to reach the level of the third sacral (S3) spinal segment, which is lower than that ever described. The lowest level of the CST fibers within the dorsal funiculus, however, reached the level of the first sacral (S1) spinal segment. In conclusion, this study demonstrates that, in the cat, there exist 6 different CSTs (crossed and uncrossed lateral, ventral, dorsal) and that the termination levels of the lateral and ventral CSTs are much lower than those described in previous reports. 相似文献
88.
89.
90.
Chad G. Ball Andrew W. Kirkpatrick Matthew Smith Robert H. Mulloy Leonard Tse Ian B. Anderson 《European journal of trauma and emergency surgery》2007,33(5):550-552
Abstract We report a case of SMV injury in a critically ill patient. The patient was a 19-year-old woman involved in a motor vehicle
collision. Her injuries included grade II splenic and renal lacerations, devascularized and lacerated right and transverse
colon, a transected transverse mesocolon, a massive shear injury of her abdominal wall, and two partial SMV transections.
At initial damage control laparotomy, the SMV was ligated, the devascularized bowel resected and a temporary abdominal closure
applied. At re-operation, a mesocaval shunt using saphenous vein was employed. The shunt failed and the patient required a
saphenous vein jump graft. Although visceral vascular injuries are rare, ligation of the SMV in a damage control situation
is acceptable. This case study is the first to discuss appropriate treatment when interruption to a patient's collateral visceral
venous drainage limits the surgeon’s ability to ligate. In these situations, bypass shunts may be successful. 相似文献