全文获取类型
收费全文 | 14074篇 |
免费 | 619篇 |
国内免费 | 70篇 |
专业分类
耳鼻咽喉 | 127篇 |
儿科学 | 289篇 |
妇产科学 | 213篇 |
基础医学 | 1745篇 |
口腔科学 | 364篇 |
临床医学 | 821篇 |
内科学 | 3493篇 |
皮肤病学 | 149篇 |
神经病学 | 1093篇 |
特种医学 | 381篇 |
外科学 | 2444篇 |
综合类 | 51篇 |
预防医学 | 392篇 |
眼科学 | 334篇 |
药学 | 1017篇 |
中国医学 | 28篇 |
肿瘤学 | 1822篇 |
出版年
2023年 | 70篇 |
2022年 | 136篇 |
2021年 | 215篇 |
2020年 | 143篇 |
2019年 | 222篇 |
2018年 | 250篇 |
2017年 | 193篇 |
2016年 | 243篇 |
2015年 | 234篇 |
2014年 | 300篇 |
2013年 | 369篇 |
2012年 | 574篇 |
2011年 | 656篇 |
2010年 | 388篇 |
2009年 | 331篇 |
2008年 | 653篇 |
2007年 | 645篇 |
2006年 | 659篇 |
2005年 | 733篇 |
2004年 | 735篇 |
2003年 | 721篇 |
2002年 | 703篇 |
2001年 | 449篇 |
2000年 | 411篇 |
1999年 | 392篇 |
1998年 | 226篇 |
1997年 | 159篇 |
1996年 | 164篇 |
1995年 | 133篇 |
1994年 | 122篇 |
1993年 | 131篇 |
1992年 | 349篇 |
1991年 | 312篇 |
1990年 | 308篇 |
1989年 | 290篇 |
1988年 | 233篇 |
1987年 | 226篇 |
1986年 | 228篇 |
1985年 | 160篇 |
1984年 | 140篇 |
1983年 | 140篇 |
1982年 | 85篇 |
1979年 | 93篇 |
1978年 | 70篇 |
1977年 | 70篇 |
1975年 | 56篇 |
1974年 | 67篇 |
1973年 | 66篇 |
1972年 | 66篇 |
1971年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
71.
72.
Seiitsu Ono Takashi Imai Shigeru Munakata Keiichi Takahashi Fumio Kanda Kazuki Hashimoto Takahiko Yamano Natsue Shimizu Koichi Nagao Mitsuo Yamauchi 《Journal of the neurological sciences》1998,160(2):565-147
During the last 10 years, we have demonstrated morphological and biochemical abnormalities of skin extracellular matrices in amyotrophic lateral sclerosis (ALS). However, currently little is known concerning collagen of the spinal cord in ALS. We measured the amount of collagen and characterized collagen at light and electron microscopic levels in posterior funiculus, posterior half of lateral funiculus and anterior horn of cervical enlargement of the spinal cord obtained from ten patients with ALS, 11 patients with other neurologic diseases (control group A), and ten patients without neurologic ones (control group B). In posterior half of lateral funiculus and anterior horn, (1) by light microscopy, there was no significant difference in vessel wall area between ALS patients and control groups A and B; (2) ultrastructurally, collagen bundles were more fragmented and widely separated, and the fibrils were randomly oriented in the perivascular space of capillaries in ALS patients, which were not observed in any areas of control groups or in posterior funiculus of ALS patients; and (3) the collagen contents in ALS were significantly lower (P<0.001 and P<0.001, respectively) than those in control groups A and B. Fragmented and widely separated collagen bundles in the interstitial tissue surrounding capillaries and markedly decreased amount of collagen in posterior half of lateral funiculus and in anterior horn of ALS could be related to the degeneration of the upper and lower motor neurons in the spinal cord in ALS, that is, selective neuronal vulnerability in ALS. 相似文献
73.
74.
M Hayashi J Kimura K Yamaki Y Suwabe M Dozen Y Imai S Oh-ishi 《Thrombosis research》1987,48(3):299-310
PAF-likely activity, detected as aggregation of washed platelets, was found in the exudate of rats with pleurisy induced by phorbol myristate acetate (PMA, 1 nmol). At 30 min after the injection of PMA, 400-500 pg of PAF was detected in the pleural exudate. An extract of the exudate was made and analysed by HPLC and by rabbit platelet aggregation. The activity was characterized as that of PAF as a result of the inhibition seen with the PAF-antagonist CV-3988 and the loss of activity by treatment with phospholipase A2. Indirect evidence was previously reported in that CV-3988 suppressed the pleural fluid accumulation in the pleurisy induced by PMA. Taken together these facts it indicates that PAF could be an important mediator of acute inflammation, especially of the plasma exudation resulting from an increase in vascular permeability. Evidence that pleural cells produce PAF was also examined in an in vitro experiment. PAF was found in the supernatant and cellular fractions of the incubation mixture of the pleural cells from normal rats when stimulated by PMA (1 microM) or A23187 (5 microM), and the results indicate that the pleural cells produce PAF and release a portion of it. 相似文献
75.
76.
Supraventricular tachyarrhythmia (SVT) such as sinus tachycardia and atrial dysrhythmia is a life-threatening problem in the period immediately following an open-heart operation. Because of their negative inotropic effects, antiarrhythmic agents are not recommended for patients with low cardiac output syndrome. A device was developed that topically cools the right atrial surface for antiarrhythmic treatment. In experiments, this device lowered right atrial temperature and did not affect the temperature of the right ventricle or the whole body. When right atrial temperature decreased from 37 degrees to 28 degrees C, heart rate was reduced from 146.3 to 109.7 beats per minute (p less than .001). Meanwhile, cardiac output and blood pressure remained within control levels. In the treatment of experimental SVT induced by the intravenous infusion of isoproterenol hydrochloride and by direct application of aconitine, this method worked effectively and was reproducible. The results demonstrated the beneficial effects of this method in the treatment of SVT in experimental studies and suggested its future clinical application following open-heart operations. 相似文献
77.
Sumiya Ishigami Shuichi Hokita Shoji Natsugoe Masahiro Tokushige Tetsushi Saihara Hirohumi Iwashige Kuniaki Aridome Takashi Aikou 《World journal of surgery》1998,22(10):1056-1060
n
= 25) and node-negative (
n
= 81) groups. Among several pathologic factors, the diameter of the tumor and lymphatic involvement were significantly correlated
with nodal involvement. Within the submucosal layer the depth of invasion and the horizontal cancerous expansion also correlated
with lymph node disease (
p
< 0.05). The size of the tumor did not correlate with the length of submucosal infiltration (
r
= 0.12,
p
= 0.1). Patients with both slight invasion into the submucosa and less than 5 mm of horizontal expansion were often negative
for lymph node involvement and thus may benefit from local surgery as an alternative to gastrectomy. 相似文献
78.
Seiji Nakata Jin Sato Kyoichi Imai Hidetoshi Yamanaka Yoshio Ichinose 《International journal of urology》1995,2(3):191-197
Background Prostate cancer is rare in Asia, but the number of patients is increasing in Japan. We conducted an epidemiological study of prostate cancer in Gunma Prefecture, Japan, to investigate the trends and characteristics of the disease.
Methods: The subjects were 1.411 prostate cancer patients newly diagnosed between 1985 and and 656 patients who died from prostate cancer between 1981 and 1992. The incidence and mortality rates were calculated by year, demographic region and age.
Results: The yearly incidence rate showed an increase but the mortality rate showed no marked fluctuations. There was no significant difference between urban and ruraI districts in either incidence or mortality rate. The incidence rate tended to be high in the northern part of the prefecture, but no marked variation in mortality rate was seen. The incidence and mortality rates in districts with a history of manganese mining were high compared to those in districts without mining. In contrast, the incidence and mortality rates in districts with a history of zinc mining were comparatively lower. Both incidence and mortality rates showed a marked increase with age. The age-specific incidence showed a double logarithmic relationship to age.
Conclusions: The increase of the yearly incidence rate might be due to changes in lifestyle and environmental factors, improved diagnostic techniques, and increased awareness among the general public regarding prostate disease. Further investigation is needed to clarify the pattern and the causes of regional differences in the incidence and mortality rates. The possibilities that manganese and zinc might be related to prostatic carcinogenesis are suggested. Int J Urol 1995:2:191–197 相似文献
Methods: The subjects were 1.411 prostate cancer patients newly diagnosed between 1985 and and 656 patients who died from prostate cancer between 1981 and 1992. The incidence and mortality rates were calculated by year, demographic region and age.
Results: The yearly incidence rate showed an increase but the mortality rate showed no marked fluctuations. There was no significant difference between urban and ruraI districts in either incidence or mortality rate. The incidence rate tended to be high in the northern part of the prefecture, but no marked variation in mortality rate was seen. The incidence and mortality rates in districts with a history of manganese mining were high compared to those in districts without mining. In contrast, the incidence and mortality rates in districts with a history of zinc mining were comparatively lower. Both incidence and mortality rates showed a marked increase with age. The age-specific incidence showed a double logarithmic relationship to age.
Conclusions: The increase of the yearly incidence rate might be due to changes in lifestyle and environmental factors, improved diagnostic techniques, and increased awareness among the general public regarding prostate disease. Further investigation is needed to clarify the pattern and the causes of regional differences in the incidence and mortality rates. The possibilities that manganese and zinc might be related to prostatic carcinogenesis are suggested. Int J Urol 1995:2:191–197 相似文献
79.
Norio Ohkoshi Hldehlro Mizusawa Nobuko Shiraiwa Shin'Ichi Shoji Katsutoshi Harada Kazuo Yoshizawa 《Muscle & nerve》1995,18(11):1265-1271
Lmmunohistochemical analyses were made of the superoxide dismutases (Mn-SOD and CuiZn-SOD) in biopsied muscles from 7 patients with mitochondrial encephalomyopathies that included mitochondrial encephalomyopathy, lactic acidosis and strokelike episodes (MELAS), and chronic progressive external ophthalmoplegia (CPEO). Mn-SOD mainly was present in the subsarcolemmal region, but it also was found in a coarsely granular, reticular, or diffuse pattern of staining within the muscle fibers. These Mn-SOD-positive fibers corresponded almost completely to the ragged-red fibers. The immunoreaction for CuiZn-SOD was weakly positive in some of the muscle fibers positive for Mn-SOD. In CPEO, Mn-SOD-positive fibers predominantly showed decreased cytochrome c oxidase (COX) activity. In MELAS, Mn-SOD-positive fibers tended to be stained deeply for COX although a few were COX-negative. These findings suggest that Mn-SOD-positive fibers can be used to make a differential diagnosis between CPEO and MELAS and that in mitochondrial encephalomyopathies Mn-SOD in the raggedred fibers may protect against oxidative stress. © John Wiley & Sons, Inc. 相似文献
80.
Nobuhiro Yuki Shuzo Sato Shoji Tsuji Kimiaki Ogawa Tadashi Miyatake 《Annals of neurology》1993,33(6):655-657
We performed human leukocyte antigens(HLA)typing for class I antigens on 19 Japanese patients with Fisher's syndrome. We demonstrated a statistically significant association between the disease and the HLA-B39 antigen. 相似文献