全文获取类型
收费全文 | 8895篇 |
免费 | 545篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 114篇 |
儿科学 | 236篇 |
妇产科学 | 166篇 |
基础医学 | 1470篇 |
口腔科学 | 275篇 |
临床医学 | 847篇 |
内科学 | 1284篇 |
皮肤病学 | 497篇 |
神经病学 | 1057篇 |
特种医学 | 399篇 |
外科学 | 1331篇 |
综合类 | 103篇 |
一般理论 | 6篇 |
预防医学 | 538篇 |
眼科学 | 199篇 |
药学 | 429篇 |
中国医学 | 2篇 |
肿瘤学 | 530篇 |
出版年
2023年 | 68篇 |
2022年 | 119篇 |
2021年 | 237篇 |
2020年 | 139篇 |
2019年 | 183篇 |
2018年 | 216篇 |
2017年 | 151篇 |
2016年 | 190篇 |
2015年 | 190篇 |
2014年 | 292篇 |
2013年 | 353篇 |
2012年 | 507篇 |
2011年 | 464篇 |
2010年 | 277篇 |
2009年 | 212篇 |
2008年 | 394篇 |
2007年 | 416篇 |
2006年 | 353篇 |
2005年 | 380篇 |
2004年 | 365篇 |
2003年 | 358篇 |
2002年 | 339篇 |
2001年 | 57篇 |
1999年 | 71篇 |
1998年 | 92篇 |
1997年 | 70篇 |
1996年 | 67篇 |
1995年 | 46篇 |
1994年 | 45篇 |
1993年 | 56篇 |
1992年 | 49篇 |
1988年 | 44篇 |
1985年 | 52篇 |
1982年 | 57篇 |
1980年 | 58篇 |
1933年 | 50篇 |
1932年 | 44篇 |
1931年 | 50篇 |
1930年 | 60篇 |
1928年 | 43篇 |
1927年 | 44篇 |
1926年 | 54篇 |
1924年 | 41篇 |
1923年 | 54篇 |
1922年 | 54篇 |
1921年 | 51篇 |
1914年 | 51篇 |
1913年 | 79篇 |
1912年 | 48篇 |
1911年 | 50篇 |
排序方式: 共有9483条查询结果,搜索用时 15 毫秒
31.
32.
Thomas W Stief Ola Ijagha Bettina Weiste Ileana Herzum Harald Renz Martin Max 《Blood coagulation & fibrinolysis》2007,18(2):179-186
This laboratory study tested new methods to analyze hemostasis alterations in septic patients. Samples of ethylenediamine tetraacetic acid (EDTA) plasma and citrated plasma were collected from 62 patients with clinical diagnosis of sepsis. Additionally, a subset of EDTA-plasma samples from each patient was stabilized 1 + 1 with 2.5 mol/l arginine, pH 8.6, to conserve the real hemostasis activation state. EDTA-arginine plasma, EDTA plasma and citrated plasma samples were tested in duplicate. The patients at admission to the intensive care unit had 36 +/- 26 (normal, 0.8 +/- 0.2) ng/ml global endotoxin reactivity, 188 +/- 66% (normal, 100 +/- 20%) fibrinogen function, 179 +/- 66% (normal, 100 +/- 20%) fibrinogen antigen, 4.0 +/- 3.6 (normal, 0.049 +/- 0.025) microg/ml D-dimer, 313 +/- 307% (normal, 100 +/- 30%) plasmin-antiplasmin complex, 8.7 +/- 11.4 (normal, 1.1 +/- 0.7) U/ml plasminogen activator inhibitor-1, 12.1 +/- 10.5 (normal, 1.3 +/- 0.4) ng/ml thrombin-antithrombin III complex, 173 +/- 62% (normal, 100 +/- 20%) thrombin, 568 +/- 225 (normal, 140 +/- 42) pg/ml tissue factor, and 2.56 +/- 2.48 (normal, 0.19 +/- 0.04) microg/ml soluble intercellular adhesion molecule-1. Endotoxin (lipopolysaccharide and/or beta-glucan) reactivity (EDTA plasma), fibrinogen function + antigen + ratio and plasminogen activator inhibitor-1 (citrated plasma), and D-dimer, soluble intercellular adhesion molecule-1, thrombin activity (EDTA-arginine-stabilized plasma) presented large aberrations in septic patients when compared with normal values and may therefore be particularly interesting as markers of hemostasis alteration. Whether the observed alterations are of clinical significance has to be determined in well defined patient groups. 相似文献
33.
Kristin L Mekeel Max R Langham Regino Gonzalez-Peralta Shiro Fujita Alan W Hemming 《Liver transplantation》2007,13(4):505-508
Severe liver disease is an unusual but potentially fatal complication of sickle-cell disease (SCD). Liver transplantation has been complicated by ongoing SCD and thrombosis. We reviewed 214 pediatric transplants done at our institution from 1990 to 2005. Three patients were transplanted for complications of SCD, including intrahepatic cholestasis and viral hepatitis. Overall patient and graft survival was 66%. One patient died after 6 years from a subdural hematoma. There were not any incidences of graft loss, primary nonfunction, or thrombosis. All 3 patients required between 1 and 4 postoperative transfusions to keep hemoglobin (Hgb) >9 g/dL with an S fraction of less than 25%. One patient required a preoperative transfusion for a hemoglobin S (HbS) fraction of 30%. Mean follow-up has been 4.2 years (range, 2.6-5.4 years). All 3 children continued to suffer sequelae from their SCD. One child suffered from recurrent sickle-cell hepatopathy and chronic graft failure. In conclusion, children with SCD can in rare instances develop acute and chronic liver failure. These children can be successfully transplanted with good outcomes. Careful attention must be paid to HbS fraction and hemoglobin level to prevent sickling and vascular thrombosis. Unfortunately, liver transplant cannot alter the natural course of the disease. 相似文献
34.
Pumice has been used as a serviceable abrasive or religious artefact since antiquity and has therefore been an object of trade. It can be found in excavations of ancient workshops all over the Mediterranean.Pumice lumps from the major pumice-bearing rhyolitic tephra units in Cappadocia—the Central Anatolian Volcanic Province, Turkey (in particular the ignimbrites Kavak, Çemilköy, Tahar, Gördeles, and the volcanic complexes of Acıgöl and Hasan Dağı), were sampled and analyzed for major and trace element concentrations using instrumental neutron activation analysis (INAA). Elements determined were Na, K, Sc, Cr, Fe, Co, Zn, As, Rb, Zr, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Th, and U.Since the distribution of those elements is characteristic of the products of a certain eruption, this “chemical fingerprint” can be used to establish the origin of an unknown pumice sample by comparison with samples of known origin. In the course of this study, it could be shown that one pumice finding from the excavation in Miletos (Turkey) probably originates from the Hasan Dağı volcanic complex in Cappadocia. Since it is known that the population in Miletos focused their trade connections on the Mediterranean, this result is somewhat surprising.Two other samples from Miletos show a very high similarity to the chemical fingerprint of pumice from the Kos Plateau Tuff (KPT; Greece): In one case, the identification is doubtless, in the other case identification as KPT seems quite probable. 相似文献
35.
36.
We present here a psychodynamic model for treating brain-injured patients. In contrast to the common assumption that brain-injured patients remain in an emotional vacuum, our model uses dream material to enable a direct access to the psychic inner life of the patient. It thus refutes the view that these patients can only benefit from supportive psychotherapy. 相似文献
37.
This investigation utilized prospective survey data to examine the influence of a research incentive ($100) and requirement (videotaping) on decisions to participate in prevention research. Individuals were significantly attracted by the incentive, and marginally deterred by the requirement. Interaction analyses revealed that the positive incentive effect was stronger among prospective participants with less education and who were otherwise less likely to participate. These findings indicate that monetary incentives can be useful for increasing participation rates, and may help reduce sampling bias by increasing rates most strongly among individuals who are typically less likely to take part in research projects. 相似文献
38.
Wilfred C. G. Peh F.R.C.R. Louis A. Gilula M.D. Max R. Kasselt M.D. 《Emergency radiology》1997,4(4):255-257
Automobile air bag inflation-caused injuries to the chest, neck, and face, in particular the orbital contents, are infrequent but recognized. We report the occurrence of multiple digital fractures in the left hand of a 30-yearold male driver as a result of sudden air bag inflation. Continued monitoring of the potential hazards of this device is suggested. 相似文献
39.
Carolien J. Bouma Wiro J. Niessen Karel J. Zuiderveld Elma J. Gussenhoven Max A. Viergever 《Medical image analysis》1997,1(4):363-377
One prerequisite for standard clinical use of intravascular ultrasound imaging is rapid evaluation of the data. The main quantities to be extracted from the data are the size and the shape of the lumen. Until now, no accurate, robust and reproducible method to obtain the lumen boundaries from intravascular ultrasound images has been described. In this study, 21 different (semi-)automated binary-segmentation methods for determining the lumen are compared with manual segmentation to find an alternative for the laborious and subjective procedure of manual editing. After a preprocessing step in which the catheter area is filled with lumen-like grey values, all approaches consist of two steps: (i) smoothing the images with different filtering methods and (ii) extracting the lumen by an object definition method. The combination of different filtering methods and object definition methods results in a total of 21 methods and 80 experiments. The results are compared with a reference image, obtained from manual editing, by use of four different quality parameters—two based on squared distances and two based on Mahalanobis distances. The evaluation has been carried out on 15 images, of which seven are obtained before balloon dilation and eight after balloon dilation. While for the post-dilation images no definite conclusions can be drawn, an automated contour model applied to images smoothed with a large kernel appears to be a good alternative to manual contouring. For pre-dilation images a fully automated active contour model, initialized by thresholding, preceded by filtering with a small-scale median filter is the best alternative for manual delineation. The results of this method are even better than manual segmentation, i.e. they are consistently closer to the reference image than the average distance of all individual manual segmentations. 相似文献
40.
Max Bader 《American journal of public health》1987,77(7):878-879