全文获取类型
收费全文 | 10918篇 |
免费 | 562篇 |
国内免费 | 81篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 341篇 |
妇产科学 | 78篇 |
基础医学 | 1499篇 |
口腔科学 | 226篇 |
临床医学 | 615篇 |
内科学 | 2978篇 |
皮肤病学 | 377篇 |
神经病学 | 742篇 |
特种医学 | 463篇 |
外科学 | 1867篇 |
综合类 | 60篇 |
预防医学 | 370篇 |
眼科学 | 256篇 |
药学 | 663篇 |
中国医学 | 21篇 |
肿瘤学 | 948篇 |
出版年
2023年 | 74篇 |
2022年 | 138篇 |
2021年 | 186篇 |
2020年 | 123篇 |
2019年 | 149篇 |
2018年 | 194篇 |
2017年 | 163篇 |
2016年 | 178篇 |
2015年 | 219篇 |
2014年 | 267篇 |
2013年 | 327篇 |
2012年 | 533篇 |
2011年 | 565篇 |
2010年 | 349篇 |
2009年 | 314篇 |
2008年 | 549篇 |
2007年 | 596篇 |
2006年 | 543篇 |
2005年 | 655篇 |
2004年 | 665篇 |
2003年 | 669篇 |
2002年 | 670篇 |
2001年 | 231篇 |
2000年 | 222篇 |
1999年 | 259篇 |
1998年 | 174篇 |
1997年 | 134篇 |
1996年 | 152篇 |
1995年 | 113篇 |
1994年 | 122篇 |
1993年 | 98篇 |
1992年 | 167篇 |
1991年 | 148篇 |
1990年 | 179篇 |
1989年 | 148篇 |
1988年 | 123篇 |
1987年 | 132篇 |
1986年 | 98篇 |
1985年 | 99篇 |
1984年 | 88篇 |
1983年 | 74篇 |
1982年 | 51篇 |
1981年 | 51篇 |
1980年 | 43篇 |
1979年 | 64篇 |
1978年 | 56篇 |
1977年 | 41篇 |
1974年 | 43篇 |
1973年 | 43篇 |
1972年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
N Ogata 《Brain research》1987,403(2):225-233
The action of gamma-aminobutyric acid (GABA) in the supraoptic nucleus was investigated using guinea pig brain slices. GABA produced a membrane depolarization accompanied by a decrease in the input resistance. The action of GABA was concentration-dependent throughout a wide range of concentrations (10(-7)-10(-3) M). In none of the cells examined, a membrane hyperpolarization was observed. The reversal potential for the depolarization induced by GABA was about 25 mV positive to the resting membrane potential. The amplitude of the GABA-induced depolarization was increased to 1.5 X the control by reducing the external Cl- from 134.2 mM to 10.2 mM. The action of GABA was readily antagonized by relatively low concentrations of bicuculline (10(-5) M). The action of GABA in the hippocampus or in the anterior hypothalamus was markedly different from that in the supraoptic nucleus, i.e. GABA produced both depolarizing and hyperpolarizing responses in the hippocampus and consistently a hyperpolarization in the anterior hypothalamus. The depolarizing but not the hyperpolarizing response in the hippocampus was selectively blocked by picrotoxin (2 X 10(-5) M) or by bicuculline (10(-5) M). The depolarizing component was dependent on the external Cl- concentration and had a reversal potential similar to that of the depolarization induced by GABA in the supraoptic nucleus. The hyperpolarizing component was resistant to bicuculline and had a reversal potential about 30 mV negative to the resting membrane potential.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
4.
Haruhiko Nakamura Norihito Kawasaki Masahiko Taguchi Hajime Kitamura 《Annals of thoracic and cardiovascular surgery》2007,13(4):254-257
A minute small-cell lung cancer measuring 8 x 5 mm was detected and serially imaged by computed tomography for about a year preceding resection. Although this solid nodule showed a short overall doubling time (76 days), the growth curve included an early phase without apparent growth prior to the phase of rapid growth. Accordingly, lung cancer cannot be ruled out when a small nodule (<10 mm) does not enlarge in the first several months of computed tomographic follow-up. 相似文献
5.
Yuji Maruyama Shigeo Yamauchi Hidetsugu Ogasawara Hajime Imura Masami Ochi Kazuo Shimizu 《Annals of thoracic and cardiovascular surgery》2006,12(1):60-62
Surgical treatment for subacute pulmonary arterial thromboembolism has previously been considered to be inappropriate. We undertook a pulmonary arterial thrombectomy and removal of a floating right heart thrombus in a patient who had been symptomatic for over a month. The pulmonary arterial pressure, which had been equal to the systemic pressure preoperatively, decreased gradually and almost normalized one month postoperatively. Pulmonary perfusion scintigraphy revealed a dramatic improvement and the patient returned to normal life activities. 相似文献
6.
Kuri Suzuki Daisuke Nishimi Hajime Morioka Masaharu Takanami 《International journal of urology》2007,14(4):370-372
The presence of blood in the ejaculate is called hematospermia or hemospermia. While often perceived as a symptom of little significance, hematospermia can cause great concern to men who experience it. We report an unusual case of hematospermia associated with pelvic arteriovenous malformation (AVM). A 60-year-old man who visited our hospital complaining of hematospermia and pollakisuria was found to have AVM and aneurysmal changes in the left side of the pelvis using computed tomography (CT). The patient was treated with steel coil embolization of the left inferior gluteal artery, and after the procedure the hematospermia and pollakisuria remained absent without flare-ups. 相似文献
7.
Aoyama Takao Yamamoto Koujirou Kotaki Hajime Sawada Yasufumi Iga Tatsuji 《Pharmaceutical research》1997,14(11):1601-1606
Purpose. The locomotive activity changes after intravenous (i.v.) administration of methylphenidate (MPD) in rats were pharmacodynamically analyzed.
Methods. MPD concentration in plasma, MPD concentration and dopamine (DA) level in striatal dialysate collected by microdialysis method, and the locomotor activity after i.v. administration of MPD (2, 5 and 10 mg/kg doses) were used for the analysis.
Results. The transport of MPD from plasma to the interstitial fluid in the brain could be expressed by the linear two-compartment model. The clockwise hysteresis between the MPD concentration and the DA level in the dialysate could be explained by the pharmacodynamic model considering Michaelis-Menten type reuptake process of the extracellular DA into the terminal of the dopaminergic nerve and its competitive inhibition by the extracellular MPD. The inhibition constant (Ki) of MPD for DA reuptake was estimated to be 41.3 ± 73.8 nM (mean ± SE), which was closely consistent with the in vitro value after correction with dialysis recovery. The relationship between DA level in dialysate and locomotor activity was expressed by the Emax model considering two contrary effects, hyperkinesia and stereotypy. The bi-phasic locomotor activity-time profiles after high dose of MPD could be represented by this model.
Conclusions. The developed model made it possible to explain the tolerance in DA increase and the complicated locomotive change induced by MPD, and may be useful for other DA reuptake inhibitors, such as amphetamine and methamphetamine. 相似文献
8.
Chronological changes in the complement system in sepsis 总被引:6,自引:0,他引:6
The time courses of serum complement levels and the severity of sepsis were compared in two groups of septic patients, one in which the patients survived (surviving group) and one in which they did not (nonsurviving group). The components of the complement system, namely, C3a, C4a, C5a, CH50, C3, C4, and C5, were measured at several points in time after the diagnosis of sepsis had been established. A 2-antibody radioimmunoassay was used to measure C3a, C4a, and C5a; the latex agglutination test was used to measure C3 and C4; nephelometry was used to measure C5; and Meyer's 50% hemolysis method was used to measure CH50. Following the diagnosis of sepsis, the levels of CH50, C3, and C4 were significantly lower in the nonsurviving than the surviving group, while the levels of C3a and C4a were significantly higher in the nonsurviving than the surviving group. The C5a levels were significantly higher in the nonsurviving than the surviving group, although no significant intergroup differences were subsequently noted. These results suggest that the serum levels of C3a, C4a, C5a, CH50, C3, and C4 could serve as indices of the severity of sepsis. Thus, monitoring the complement system may be useful for predicting the outcome of patients with sepsis. 相似文献
9.
Y Moizumi Y Abe M Hata Y Tsuru I Suzuki Y Ogata 《Kyobu geka. The Japanese journal of thoracic surgery》1990,43(13):1052-1055
The centrifugal pump (bio-pump) as a temporary shunt during the operation of the descending thoracic aortic aneurysms was used as effective means of providing adequate circulation to the lower body. But in the acute excessive bleeding, estimates of the flow to the abdominal viscera as well as spinal cord are variable. We employed bio-pump with an interposed soft reservoir under low dose systemic heparinization in 2 cases of the descending thoracic aortic aneurysms. Both cases had been maintained adequate flow and perfusion pressure in the time of acute excessive hemorrhage, and there were no evidence of the organ failures due to microembolism. Furthermore, postoperative hemorrhage by using low dose heparin seemed to be unrisky. Compared with the previous method, bio-pump with an interposed soft reservoir provides adequate circulation to the lower body even if acute excessive bleeding occurred. 相似文献
10.
Roberto Civitelli M.D. Eturo Ogata Louis V. Avioli Gary Stein Samuel Edelstein John A. Eisman Yasuho Nishii Hajime Orimo Jane Lian Takuo Fujita Yasufumi Hayashi Shigeaki Kato Tadashi Kobayashi Hirotoshi Morii Rikushi Morita Toshitaka Nakamura Yoshiki Seino Masataka Shiraki Tatsuo Suda Naoyuki Takahashi Hideaki Takahashi Tastuhiko Tanisawa Akifumi Tokita 《Calcified tissue international》1995,57(6):409-414