全文获取类型
收费全文 | 30765篇 |
免费 | 2053篇 |
国内免费 | 157篇 |
专业分类
耳鼻咽喉 | 265篇 |
儿科学 | 450篇 |
妇产科学 | 312篇 |
基础医学 | 4681篇 |
口腔科学 | 935篇 |
临床医学 | 2962篇 |
内科学 | 7333篇 |
皮肤病学 | 473篇 |
神经病学 | 3469篇 |
特种医学 | 1878篇 |
外科学 | 4184篇 |
综合类 | 177篇 |
一般理论 | 11篇 |
预防医学 | 1235篇 |
眼科学 | 595篇 |
药学 | 1713篇 |
中国医学 | 52篇 |
肿瘤学 | 2250篇 |
出版年
2023年 | 246篇 |
2022年 | 261篇 |
2021年 | 819篇 |
2020年 | 508篇 |
2019年 | 705篇 |
2018年 | 789篇 |
2017年 | 614篇 |
2016年 | 880篇 |
2015年 | 995篇 |
2014年 | 1241篇 |
2013年 | 1531篇 |
2012年 | 2515篇 |
2011年 | 2517篇 |
2010年 | 1511篇 |
2009年 | 1349篇 |
2008年 | 2220篇 |
2007年 | 2228篇 |
2006年 | 2154篇 |
2005年 | 2023篇 |
2004年 | 1754篇 |
2003年 | 1653篇 |
2002年 | 1550篇 |
2001年 | 273篇 |
2000年 | 200篇 |
1999年 | 283篇 |
1998年 | 311篇 |
1997年 | 234篇 |
1996年 | 168篇 |
1995年 | 158篇 |
1994年 | 124篇 |
1993年 | 90篇 |
1992年 | 62篇 |
1991年 | 63篇 |
1990年 | 41篇 |
1989年 | 58篇 |
1988年 | 43篇 |
1987年 | 36篇 |
1986年 | 43篇 |
1985年 | 37篇 |
1984年 | 31篇 |
1983年 | 37篇 |
1982年 | 39篇 |
1981年 | 39篇 |
1980年 | 30篇 |
1977年 | 24篇 |
1975年 | 23篇 |
1938年 | 24篇 |
1937年 | 30篇 |
1936年 | 25篇 |
1935年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
121.
122.
Dao Yin Xie Stefan Hassenstein Martin Oberhoff Hartmut Hanke Andreas Baumbach Kristian Hohla Karl Konstantin Haase Karl Rüdiger Karsch 《Lasers in surgery and medicine》1993,13(6):618-624
A modified exeimer laser energy delivery system was used to irradiate 100 segments of normal and fibrous aorta in vitro. The laser beam was scanned into 8 fiber bundles consisting of 50 fibers each resulting in a reduction of the applied pulse energy. The total repetition rate was increased to 150 Hz in order to keep the repetition rate per fiber bundle close to 20 Hz and to minimize thermal injury. The results demonstrate that effective ablation (etch rate per 8 pulses > 2.0 μm) occurred at an energy fluency of 50 mJ/mm2 in both normal and fibrous aorta. Tissue damage (carbonization, tissue separation, fissures, cracks, and vacuolization) was in a range of 100 ± 28 to 152 ± 30 μm for normal aorta and in a range of 57 ± 35 to 110 ± 39 μm for fibrous aorta. We conclude that effective ablation of normal and fibrous human aorta can be achieved by the application of smooth excimer laser coronary angioplasty. This improvement of excimer laser technology may result in a reduction of shock wave- and cavitation-induced damage leading to a reduction of tissue injury. However, this awaits further in vitro and in vivo confirmation. © 1993 Wiley-Liss, Inc. 相似文献
123.
Danuta Knapikowa Zbigniew Andreasik Stefan Kwiatkowski Marek Okrojek Roman Smolik Krzysztof Szczerba 《International archives of occupational and environmental health》1988,60(5):351-353
Summary We examined 81 men exposed for a long time to carbon disulphide (CS2) and tested the possible electrocardiographic (ECG) changes of ischemic heart disease (I.H.D.). The subjects were examined twice in two years. In order to make the ECG evaluation more objective, the Minnesota Code was applied. Two obligatory ECG examinations and only one submaximal effort test were carried out. For comparative evaluation, the control group was examined once. We proved that, in spite of the accepted opinion concerning the atheromatous action of CS2, this compound does not cause ECG symptoms of I.H.D. in a higher percentage of exposed persons. It also does not cause any significant increase in I.H.D. symptoms in dynamic ECG observations. 相似文献
124.
125.
126.
Matthew D Robson Peter D Gatehouse Graeme M Bydder Stefan Neubauer 《Magnetic resonance in medicine》2004,51(5):888-892
Phosphorus was imaged in vivo in human cortical and trabecular bone and the T(1) and T(2) (*) were measured. An ultrashort TE (UTE) pulse sequence (TE = 70 microm) was used with half pulse excitation and radial mapping of k-space from the center out. T(2) (*) was measured using multiple echo times and T(1) was measured both by saturation recovery and by a method using different RF pulse amplitudes. Seven normal subjects (32-85 years) were examined. Phosphorus was imaged, with a true in-plane resolution of 2.9 x 2.9 mm and a signal-to-noise ratio (SNR) of 19:1, in both cortical and trabecular bone. The mean T(2) (*) value was 207 +/- 12 micros, and the mean T(1) value was 8.6 +/- 3.0 sec. Images and measurements were obtained in realistic times on a clinical MR system. This may provide a new approach to characterizing disease of bone. 相似文献
127.
Referring to the strong immunostimulating activity of combinations of lipophilic agents and dextran sulphate, conjugates with chemical determinants of both types of adjuvants were synthesized and then examined for immunostimulatory capabilities in mice. Saturated fatty acids with varying chain lengths and sulphate groups were coupled covalently at defined ratios to the polysaccharide Ficoll (MW 400,000). Chemical analysis of 60 of the sulpholipopolysaccharides synthesized revealed that the number of sulphate groups per monosaccharide unit varied from 0 to 1.6, and the number of lipid groups from 0 to 0.8. Adjuvanticity of these conjugates for the humoral immune response was determined using sheep red blood cells (SRBC) and dinitrophenyl-haptenated bovine serum albumin (DNP-BSA) as antigens. Five days after intraperitoneal injection of adjuvant and antigen, the numbers of direct anti-SRBC plaque-forming cells (PFC) in the spleen were determined. Anti-DNP antibody titres were measured from 1 to 4 weeks after immunization. PFC responses to 2 X 10(6) SRBC were augmented up to a 100-fold by conjugates of Ficoll and sulphate (sulphopolysaccharides: SPs) or lipid groups (lipopolysaccharides: LPs). Introduction of low or moderate numbers of lipid groups in SPs reduced adjuvanticity. Adjuvant activity of sulpholipopolysaccharides (SLPs) with varying sulphate and high lipid content depended on the sulphate contents and the chain length of the lipids. Sulphate reduced adjuvanticity of the SLPs, and the number of sulphate groups required for complete annihilation increased with the chain length of the lipid. LPs and SLPs, including conjugates that did not enhance anti-SRBC PFC responses, augmented serum antibody responses to DNP-BSA while SPs were hardly effective. 相似文献
128.
129.
Hoschek Stefan Hoschek-Risslegger Ursula Fiegl Michael Zabernigg August Pall Georg Auberger Thomas Gunsilius Eberhard Schmid Thomas Jamnig Herbert Hilbe Wolfgang 《Wiener Medizinische Wochenschrift》2007,157(21):562-568
Wiener Medizinische Wochenschrift - Aggressives Tumorwachstum, frühe Metastasierung und hohe Assoziation mit intensivem Nikotinkonsum sind die Charakteristika des kleinzelligen... 相似文献
130.
Stefan Tigges M.D. B. J. Manaster M.D. Ph.D. Gordon Carson M.D. 《Emergency radiology》1996,3(3):105-112
Although magnetic resonance imaging is the most accurate imaging method of evaluating the anterior cruciate ligament, several
plain radiographic signs suggestive of anterior cruciate ligament injury have been described. Plain radiographs also play
an important role in evaluating anterior cruciate ligament reconstruction. 相似文献