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991.
研究了几种气温、同一活动水平以及相同气温、不同体力负荷下的各部位体表温度变化。实验结果表明:(1)进一步确认在同一气温下头颈部皮肤温度分布的不均匀性,并表明各部位受气温的影响程度也不尽相同。(2)在同一气温下头颈部及身体其它部位的皮肤温度变化并不与体力负荷程度呈特定关系,并分析了产生这一现象的原因。(3)根据下肢为主的体力负荷对全身体表温度的影响情况,认为个体调温装备的区域性流量分配比例随身体活动形式改变而改变的必要性并不很大。由此,可以减少服装设计的复杂性。  相似文献   
992.
作者用SC1001钠盐(200mg/kg)注入家兔腹腔内,观察其对呼吸频率、心率、直肠温度和皮层电图的影响。实验结果表明,对家兔的呼吸频率、直肠温度有轻微的抑制作用,对中枢神经活动有明显的抑制作用,对心率有加快作用。  相似文献   
993.
A.J. Cox 《Biomaterials》1987,8(6):500-502
The hydrated surface of a hydrogel-coated latex urinary catheter has been examined using low temperature SEM, and its appearance compared with those of some other catheter surfaces. The effect of the coating is to smooth over most of the ripples and fissures of the underlying latex. On hydration the hydrogel surface becomes even smoother, with shallower furrows. The surface topography compares favourably with that of 100% silicone, which has a uniformly rippled yet smooth appearance.  相似文献   
994.
995.
Temperature Dependence of Anuran Distortion Product Otoacoustic Emissions   总被引:2,自引:0,他引:2  
To study the possible involvement of energy-dependent mechanisms in the transduction of sound within the anuran ear, distortion product otoacoustic emissions (DPOAEs) were recorded in the northern leopard frog over a range of body temperatures. The effect of body temperature depended on the stimulus levels used and on the hearing organ under investigation. Low-level DPOAEs from the amphibian papilla (AP) were reversibly depressed for decreased body temperatures. Apparently, DPOAE generation in the AP depends on metabolic rate, indicating the involvement of active processes in the transduction of sound. In contrast, in the other hearing organ, the basilar papilla (BP), the effects of body temperature on DPOAEs were less pronounced, irrespective of the stimulus levels used. Apparently, metabolic rate is less influencing DPOAE generation. We interpret these results as evidence that no amplifier is involved in sound transduction in the BP. The passive functioning of the anuran BP would place this hearing organ in a unique position within tetrapod hearing, but may actually be beneficial to ectothermic species because it will provide the animal with a consistent spectral window, regardless of ambient or body temperature.  相似文献   
996.
The effects of Ringer's acetate (RAc) infusion with different temperatures, 18d?C compared to 36d?C, were studied in 20 healthy volunteers. An infusion volume of 20% of the estimated extracellular volume was given over 45 min. Before and after the RAc infusion, interstitial colloid osmotic pressure and interstitial fluid hydrostatic pressure were measured on the lateral part of the thorax and in the lower leg. Blood sampling and pressure measurements were performed through a cannula placed in the left radial artery, and arterial oxygen saturation was measured by pulse oximetry. Atrial peptides ANF (99–126) and ANF (1–98) in plasma were measured as indicators of volume loading. Cold RAc infusion increased mean arterial pressure from 82 (s.d. ± 7) to 96 (s.d. ± 9) mmHg (10.9–12.8 kPa) at the end of the infusion with a simultaneous fall in heart rate. Warm RAc infusion gave no changes in blood pressure or heart rate. The arterial oxygen saturation during the infusion of cold RAc was higher than during warm RAc infusion. Cold infusion produced the expected haemodilution with a fall in erythrocyte volume fraction (EVF) from 0.39 (± 0.03) to 0.33 (± 0.03) and a fall in plasma colloid osmotic pressure (COPp) from 21.7 (± 1.1) mmHg to 15.0 (± 1.3) mmHg (2.9–2.0 kPa). Warm infusion induced a nearly identical haemodilution. Interstitial colloid osmotic pressure fell from 11.6 (± 2.3) mmHg to 8.9 (± 2.7) mmHg (1.5–1.2 kPa) after warm infusion while cold infusion gave no changes. The changes in interstitial fluid hydrostatic pressure were not significant. Cold infusion induced a higher diuresis compared to warm RAc infusion. ANF increased during cold, but not during warm infusion. We conclude that infusions of RAc at 18d?C vs. 36d?C have different volume effects. Cold infusion increased blood pressure and diuresis, while warm infusion induced peripheral vasodilation with increased capillary leakage and subcutaneous oedema formation.  相似文献   
997.
低温核供热堆辐射防护安全准则   总被引:1,自引:0,他引:1       下载免费PDF全文
作者提出了低温核供热堆辐射防护安全准则的建议,即①要求半径50km范围内加权人口不超过106;②禁区半径为250m;③限制发展区半径2km;④低温核供热堆正常运行期间,由于放射性向环境释放所致公众个人剂量(全身或有效)不应超过0.1mSv/a,集体剂量不超过100man·Sv/a;⑤低温核供热堆事故期间,公众个人剂量不超过5mSv,集体剂量不超过1000man·Sv;⑥低温核供热堆正常运行期间,放射性流出物(气体、液体)的释放量不应超过国标GB6249规定值的2/5;⑦热网水中的放射性活度不应超过0.37Bq/L;⑧建议应急状态分为三级,即应急待命、厂房应急和场区应急。  相似文献   
998.
Thoracic electrical impedance and fluid balance during aortic surgery   总被引:1,自引:0,他引:1  
Indices of fluid balance were evaluated during and after aortic surgery in 16 consecutive patients. Thoracic electrical impedance (TI), heart rate (HR), central venous (CVP), pulmonary artery mean (PAMP), pulmonary wedge (PWP) and mean arterial (MAP) pressure as well as fourteen arterial and venous blood gas variables were followed. Consistent with a reduction of TI by 4.2 (—5.2 to 9.2) Ohm (median and range) during the operation, fluid balance was in excess of 1.8 (—0.1 to 3.3) 1 when evaporation was not taken into account, and it remained elevated by 1.3 (0.0 to 5.4) 1 on the first postoperative morning. The HR, MAP and PWP remained stable, while CVP and PAMP decreased by 6 (-2 to 13) and 6 (-1 to 22) mmHg, respectively. Of the determined variables only TI revealed a meaningful correlation to fluid balance (rho= —0.41; P <0.01). Haemoglobin concentrations increased in proportion to the administered packed erythrocytes, while arterial oxygen saturation, pH and base excess decreased in proportion to the excess fluid. The results indicate that while central venous and pulmonary artery mean pressures gave the impression of a volume deficit, the positive fluid balance was mirrored by thoracic electrical impedance, and that even a minor increase of fluid balance may affect pulmonary function in patients subjected to aortic surgery.  相似文献   
999.
在文献[1]的基础上,本文将平面体温场分成了九类  相似文献   
1000.
Gene therapy is a promising approach to the treatment of many forms of disease, including cancer. Of critical concern in its implementation is the ability to control the location, duration, and level of expression of the therapeutic gene. Here, we propose the use of local heat in combination with a heat-sensitive promoter to help accomplish this. Certain members of the family of heat shock protein (hsp) promoters display a regulation that depends strongly on temperature. We present a study of natural hsp70 induction in rat leg by MRI-guided focused ultrasound to investigate the hsp70 promoter as a possible candidate for use in control of gene expression with local heat. A temperature increase of 5–8°C in the focal region for 45 minutes led to a differential expression of the hsp70 mRNA between the focal region and the surrounding tissue ranging from a factor of 3 to 67.  相似文献   
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