全文获取类型
收费全文 | 12977篇 |
免费 | 913篇 |
国内免费 | 199篇 |
专业分类
耳鼻咽喉 | 120篇 |
儿科学 | 377篇 |
妇产科学 | 76篇 |
基础医学 | 1034篇 |
口腔科学 | 94篇 |
临床医学 | 1453篇 |
内科学 | 936篇 |
皮肤病学 | 43篇 |
神经病学 | 1436篇 |
特种医学 | 427篇 |
外科学 | 819篇 |
综合类 | 1226篇 |
一般理论 | 1篇 |
预防医学 | 1047篇 |
眼科学 | 445篇 |
药学 | 3839篇 |
17篇 | |
中国医学 | 331篇 |
肿瘤学 | 368篇 |
出版年
2023年 | 212篇 |
2022年 | 380篇 |
2021年 | 575篇 |
2020年 | 569篇 |
2019年 | 477篇 |
2018年 | 489篇 |
2017年 | 454篇 |
2016年 | 417篇 |
2015年 | 534篇 |
2014年 | 1085篇 |
2013年 | 915篇 |
2012年 | 872篇 |
2011年 | 912篇 |
2010年 | 718篇 |
2009年 | 631篇 |
2008年 | 624篇 |
2007年 | 499篇 |
2006年 | 404篇 |
2005年 | 330篇 |
2004年 | 334篇 |
2003年 | 243篇 |
2002年 | 178篇 |
2001年 | 183篇 |
2000年 | 160篇 |
1999年 | 133篇 |
1998年 | 125篇 |
1997年 | 127篇 |
1996年 | 106篇 |
1995年 | 94篇 |
1994年 | 90篇 |
1993年 | 88篇 |
1992年 | 86篇 |
1991年 | 78篇 |
1990年 | 58篇 |
1989年 | 51篇 |
1988年 | 74篇 |
1987年 | 53篇 |
1986年 | 54篇 |
1985年 | 84篇 |
1984年 | 73篇 |
1983年 | 62篇 |
1982年 | 55篇 |
1981年 | 61篇 |
1980年 | 55篇 |
1979年 | 47篇 |
1978年 | 39篇 |
1977年 | 39篇 |
1976年 | 44篇 |
1975年 | 25篇 |
1973年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Summary Seventy-one Caucasian orbits (36 right, 35 left) were studied by dissection. The diameter of the ophthalmic a. (2 mm from the origin) was 1.54 ± 0.04 mm (male) and 1.31 ± 0.05 mm (female). In individual cases, there were no significant differences in vessel diameter between the right and left sides but, differences in vessel diameter between males and females were more commonly observed in the arteries which leave the orbit (extraorbital group), the individual vessels having a larger diameter in males. The incidence of the ophthalmic a. passing in the orbit medially under the optic n. was 18.6%. The lacrimal a. was observed to arise from the ophthalmic a. in only 82.5% of the cases examined, 15.9% of the cases showed the origin to be at the anastomotic branch of the middle meningealThis article is dedicated to Pr Dr Hoepke on occasion of his 100th birthday 相似文献
102.
Viral infections of the central nervous system and immune responses to these infections cause a variety of neurological diseases. Infection of weanling mice with Sindbis virus causes acute nonfatal encephalomyelitis followed by clearance of infectious virus, but persistence of viral RNA. Infection with a neuroadapted strain of Sindbis virus (NSV) causes fatal encephalomyelitis, but passive transfer of immune serum after infection protects from fatal disease and infectious virus is cleared. To determine whether persistent NSV RNA is associated with neurological damage, we examined the brains of recovered mice and found progressive loss of the hippocampal gyrus, adjacent white matter, and deep cerebral cortex associated with mononuclear cell infiltration. Mice deficient in CD4(+) T cells showed less tissue loss, while mice lacking CD8(+) T cells showed lesions comparable to those in immunocompetent mice. Mice deficient in both CD4(+) and CD8(+) T cells developed severe tissue loss similar to immunocompetent mice and this was associated with extensive infiltration of macrophages. The number of CD4(+) cells and macrophage/microglial cells, but not CD8(+) cells, infiltrating the hippocampal gyrus was correlated with the number of terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling positive pyramidal neurons. These results suggest that CD4(+) T cells can promote progressive neuronal death and tissue injury, despite clearance of infectious virus. 相似文献
103.
Y. V. Panchin Y. I. Arshavsky T. G. Deliagina G. N. Orlovsky L. B. Popova A. I. Selverston 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1996,109(2):361-365
The locomotor activity in the marine mollusc Clione limacina has been found to be strongly excited by serotonergic mechanisms. In the present study putative serotonergic cerebropedal neurons were recorded simultaneously with pedal locomotor motoneurons and interneurons. Stimulation of serotonergic neurons produced acceleration of the locomotor rhythm and strengthening of motoneuron discharges. These effects were accompanied by depolarization of motoneurons, while depolarization of the generator interneurons was considerably lower (if it occurred at all). Effects of serotonin application on isolated locomotor and non-locomotor pedal neurons were studied. Serotonin (5×10-7 to 1×10-6 M) affected most pedal neurons. All locomotor neurons were excited by serotonin. This suggests that serotonergic command neurons exert direct influence on locomotor neurons. Effects of serotonin on nonlocomotor neurons were diverse, most neurons being inhibited by serotonin. Some effects of serotonin on locomotor neurons could not be reproduced by neuron depolarization. This suggests that, along with depolarization, serotonin modulates voltage-sensitive membrane properties of the neurons. As a result, serotonin promotes the endogenous rhythmical activity in neurons of the C. limacina locomotor central pattern generator. 相似文献
104.
目的探讨中枢神经系统感染患儿血脑屏障(blood-brain barrier,BBB)与脑脊液(cerebrospinal-fluid,CSF)白蛋白指数的变化。方法采用溴甲酚绿法和免疫比浊法检测18例化脓性脑膜炎患儿急性期、恢复期及22例病毒性脑炎患儿急性期血清和CSF中白蛋白水平,并计算出CSF白蛋白指数。与正常对照组比较。结果化脓性脑膜炎、病毒性脑炎患儿急性期CSF白蛋白、CSF白蛋白指数显著高于正常对照组(P〈0.001),且化脑组显著高于病脑组(P〈0.001)。化脑组恢复期患儿CSF白蛋白、CSF白蛋白指数与对照组无明显差异(P〉0.05)。结论监测CSF白蛋白和CSF白蛋白指数的水平可作为化脓性脑膜炎和病毒性脑炎早期诊断、鉴别诊断,以及判断BBB损伤程度的参考指标。 相似文献
105.
The effect of various immunomodulators on the induction of experimental autoimmune encephalomyelitis (EAE) is evaluated in the Lewis rat. Bordetella pertussis (BP) is the optimal inductor of EAE in this rat strain. Treatment of the animals with BP either before or after or simultaneously with guinea-pig spinal cord preparation (GpSC) resulted in an EAE about two weeks thereafter. Additional injection of living BCG, of CFA, IFA (incomplete Freund's adjuvant) or Vibrio cholerae neuraminidase (VCN) did not augment or mitigate the effect induced by BP or GpSC. Living BCG, IFA, VCN or Corynebacterium parvum (CP) did not induce EAE when given in combination with GpSC but without BP. CFA combined with GpSC only occasionally induced EAE. However, EAE could be induced by the combination of CFA and GpSC or IFA and GpSC in a part of the animals tested if they had been pretreated or simultaneously been injected with living BCG by intravenous route. EAE could not be enhanced by the additional injection of VCN. Surprisingly, most of the animals peracutely died after injection of CFA and BP in combination with GpSC when they had been pretreated with CP. This effect was most pronounced when pretreatment was done on day -4. No acute effect could be seen when CP was given simultaneously to CFA, BP and GpSC. Animals which did not peracutely succumb developed EAE similarly as those in the positive control groups. CP treatment simultaneously with BP but without CFA resulted in a reduction of the EAE specific mortality. This reduction could not be seen if treatment with CP was done after injection of GpSC and BP. 相似文献
106.
W. Berger K. Berger J. Berndt K. Giese 《Pflügers Archiv : European journal of physiology》1978,374(3):205-210
In cats anesthetized with chloralose-urethane, the central respiratory chemoreceptors were exposed to mock CSF of pH 7.02,
7.20, or 7.57. The right carotid body was simultaneously stimulated by intracarotid injections of 40, 80, or 160 μg sodium
cyanide in 200 μl Ringer solution. The left carotid nerve and, in some animals, both vagosympathetic truncs were dissected.
It could be demonstrated the the increase in ventilation produced by application of NaCN to the peripheral chemoreceptors
is significantly larger at high than at low mock CSF pH (i.e. at low than at high central stimulus intensity). In vagotomized
cats the responses of VT and gelai to NaCN similarly depend upon CSF pH; they are somewhat larger, though, than in intact animals. These results are
discussed as compared with results reported by different authors.
Supported by the Deutsche Forschungsgemeinschaft (Be 477) 相似文献
107.
Ecotropic and dualtropic mink cell focus-inducing murine leukemia viruses can induce a wide spectrum of H-2 controlled lymphoma types 总被引:5,自引:0,他引:5
Neonatal infection of C57BL and BALB/c mice by cloned ecotropic and dualtropic mink cell focus-inducing (MCF) murine leukemia viruses (MuLV) induces a wide spectrum of different lymphomas of T, B, and non-T/non-B cell types. Oncogenic dualtropic MCF viruses and poorly oncogenic ecotropic MuLV act synergistically in lymphomagenesis. Within one mouse strain virus-induced T-cell lymphomas arise earlier than B-cell lymphomas after neonatal inoculation of a single-cloned MuLV. The host genetic constitution, notably the H-2 complex has a marked influence on lymphoma type. This H-2 influence can be explained by an H-2-linked difference in penetration of the thymus early in life by oncogenic thymotropic MuLV, which in turn is correlated with, but not necessarily due to the magnitude of the anti-MuLV antibody response. 相似文献
108.
Hamsters in deep experimentally induced hypothermia, at body temperatures between 7 degrees C and 11.5 degrees C, were microinjected with 5-HT and ACh at brain sites in the anterior-preoptic area of the hypothalamus (AH/POA). ACh or 5-HT was injected into an AH/POA site at different starting core temperatures in different groups of hypothermic hamsters. Colonic temperatures (Tc) were maintained, following He-Cold induction, in a temperature controlled environmental chamber and measured with a YSI thermister probe and YSI telethermometer. Injections of either 5-HT or ACh at Tc's between 7.0 degrees C and 9.0 degrees C elicited only modest increases in Tc i.e., 0.3 degrees C--0.6 degrees C, respectively. As Tc increased, however, to ranges between 9.1 degrees C--10.0 degrees C and in different animals to greater than 10 degrees C both ACh and 5-HT at the same sites elicited significant increases in Tc, 1.5 degrees C for 5-HT and 2.2 degrees C for ACh compared to saline injections. These data suggest that at the lowest Tc's we are observing a "cold block" of temperature sensitive sites in the AH/POA. Increasing the starting Tc beyond 9.0 degrees C however, evokes significant increases in heat-gain following AH/POA injection of either ACh or 5-HT. These data are consistent with Myers' observations concerning the organization of heat-gain mechanisms at AH/POA sites. In addition, they suggest that both the afferent limb of the heat-gain circuit (5-HT) and the efferent limb of the circuit (ACh) are functionally impaired when Tc is close to the physiological limit in the He-Cold hypothermic hamster. 相似文献
109.
110.
S. -E. RICKSTEN A. MEDEGÅRD I. CURELARU B. GUSTAVSSON L. E. LINDER 《Acta anaesthesiologica Scandinavica》1986,30(1):13-17
The pressure in the proximal axillary vein (AVP) was compared with central venous pressure (CVP) in eight patients during and after elective abdominal surgery. Both pressures were recorded from soft, elastic, polyurethane catheters inserted in the basilic or cephalic veins ("half-way" catheters), punctured at the fossa cubiti (AVP), and via the right jugular vein (CVP). The AVP and CVP were recorded simultaneously using hydrostatic, conventional disposable venous pressure measurement sets. The measurements were performed during intermittent positive pressure ventilation with positive end-expiratory pressure from 0 to 7.5 cmH2O (0-0.74 kPa), as well as during spontaneous breathing. During both controlled and spontaneous respiration, small mean differences (0.2-1.0 cmH2O) (0.02-0.1 kPa), and a highly significant (P less than 0.001) positive correlation between CVP- and AVP-values were found. An increase of 1 cmH2O (0.10 kPa) in the CVP was associated with an increment of practically identical order (0.99-1.04 cmH2O) (0.10-0.11 kPa) in the AVP. The results suggest that monitoring of the AVP by a basilic "half-way" catheter produces diagnostic information similar to that from the measurement of the CVP from subclavian, external or internal jugular, as well as "long-way" brachial catheter, with no risk of the major mechanical complications which accompany the use of the latter catheters. 相似文献