首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3895篇
  免费   241篇
  国内免费   27篇
耳鼻咽喉   99篇
儿科学   119篇
妇产科学   76篇
基础医学   759篇
口腔科学   144篇
临床医学   348篇
内科学   674篇
皮肤病学   160篇
神经病学   338篇
特种医学   262篇
外国民族医学   1篇
外科学   555篇
综合类   23篇
一般理论   1篇
预防医学   185篇
眼科学   82篇
药学   179篇
中国医学   5篇
肿瘤学   153篇
  2022年   29篇
  2021年   52篇
  2020年   38篇
  2019年   65篇
  2018年   68篇
  2017年   65篇
  2016年   75篇
  2015年   65篇
  2014年   79篇
  2013年   120篇
  2012年   143篇
  2011年   149篇
  2010年   104篇
  2009年   97篇
  2008年   170篇
  2007年   162篇
  2006年   178篇
  2005年   185篇
  2004年   135篇
  2003年   129篇
  2002年   136篇
  2001年   120篇
  2000年   128篇
  1999年   105篇
  1998年   73篇
  1997年   46篇
  1996年   55篇
  1995年   38篇
  1994年   34篇
  1993年   41篇
  1992年   57篇
  1991年   64篇
  1990年   69篇
  1989年   75篇
  1988年   83篇
  1987年   66篇
  1986年   57篇
  1985年   49篇
  1984年   37篇
  1983年   38篇
  1980年   27篇
  1979年   41篇
  1977年   34篇
  1976年   26篇
  1975年   43篇
  1973年   29篇
  1971年   28篇
  1970年   31篇
  1969年   27篇
  1968年   27篇
排序方式: 共有4163条查询结果,搜索用时 31 毫秒
71.
Telomerase activity and telomere length were analyzed in a total of 59 surgically removed primary renal cell carcinoma (RCC). The study includes tissue from the centre of the tumor, several different peripheral tumor areas, metastases and secondary tumors. None of the normal renal cortex tissues used as control exhibited telomerase activity. In contrast, telomerase activity was detected in 55 out df 59 (=93%) tested primary RCC. There was no case with intratumoral heterogeneity concerning the telomerase activity status. All metastases and secondary tumors were telomerase-positive. In the four telomerase deficient tumors all measured telomeric repeat fragments were shortened in comparison to the normal tissue. As these patients exhibit no metastases or secondary tumors a less malignant variant of RCC is supposed. There was no correlation between telomerase activity and specific histopathological subtypes of RCC or specific chromosomal aberrations. As telomerase activity is not associated with advanced stages of tumors it may be an important early event in the development of RCC. Thus, telomerase activity may be a prevalent marker for early and late stages of all subtypes of RCC.  相似文献   
72.
The interceptive activity of 2 new synthesized steroid compounds: STS 153 (17 beta-Phenylaminocarbonyloxy-estra-1,3,5(10)-triene-3-methyl ether and STS 287 (16 alpha-Bromo-17 beta-[N',N'-dimethylhydrazino]-carbonyloxy-estra-1,3,5(10)-triene-3-methyl ether) and of 17 alpha-Ethynylestradiol was investigated in baboons.--Postcoital oral administration of 1--3 mg/kg b. w. STS 153 for 5--7 days and of 1 mg/kg b. w. STS 287 for 5 days resulted in a fertility inhibition of about 90% and 95% respectively. A dose of 2 mg/kg b. w. of ethynylestradiol was necessary to attain complete fertility inhibition. Following administration of STS 153 and STS 287, side effects were not observed. Pharmacokinetic aspects are discussed.  相似文献   
73.
Doppman  JL; Brennan  MF; Dunnick  NR; Kahn  CR; Gorden  P 《Radiology》1981,138(3):557-562
The palpation and enucleation of occult insulinomas (less than 15 mm) can be a difficult surgical problem even with good arteriographic localization. In the authors' limited experience, confirmation of arteriographic findings by pancreatic venous sampling provided little additional localizing information. However, if arteriography is negative or equivocal, venous sampling can indicate the segment of pancreas to be "blindly" resected if the adenoma is not palpable. Venous sampling may be misleading in polyendocrine syndromes because of the frequency of multiple adenomas and variable hormone production.  相似文献   
74.
The euthyroid hyperthyroxinemia (EHT) is characterized on the one hand by a normal basal THS or TRH-TSH response but also by high plasma values of total thyroxine (TT4) on the other. However if only TT4 is assessed, "hyperthyroidism" may be diagnosed erroneously. EHT may be caused by an increase of specific thyroxine binding proteins which may be hereditary (permanent) or acquired (transient). The most frequent disturbance is due to an estrogen induced increase of thyroxine binding globulin (TBG) in the course of pregnancy, anticonceptive drugs or estrogen treatment. The albumin associated HT (FDH syndrome), first reported in 1979, has autosomal dominant traits. 144 patients with FDH syndrome were observed during the period between 1984 and 1990, i.e. 7% (1986) of all hyperthyroid patients explored. Family screening is required to prevent unjustified treatment. Additionally existing disturbances of thyroid function as well as other protein binding anomalies may both cause problems in differential diagnosis. Prealbumin associated hyperthyroxinemia (PAAH), first published in 1982, may be due to an inherited increase in affinity, but may also be the consequence of a true elevation of prealbumin plasma concentration in the course of an islet cell cancer; both conditions are extremely rare. Nearly as rare are patients with plasma autoantibodies directed against T4 and/or T3 (5 cases); yet, a reverse T3 autoantibody could be observed in merely 1 case. By means of our modified radio-thyroxine-agarosegel-iceelectrophoresis all such protein anomalies may be diagnosed and differentiated in 1 procedure. Moreover, all other types of EHT must be taken into consideration by differential diagnosis.  相似文献   
75.
The reliability of roentgenological demonstration of the urethra in prostatic cancer has been examined and the advantages of double contrast retrograde urethrocystography and resistance miction-cystourethrography are accentuated. These investigations are indicated in preparation for radiotherapy, operative therapy, transurethral resection and after reduced uroflow.  相似文献   
76.
BACKGROUND: Chronic prostatic pain is still a diagnostic and therapeutic problem. The clinical observation that prostatic and pelvic pain is accompanied by motoric and sensoric disorders of the pelvic floor muscles led to the hypothesis that prostatic pain roots in a changed processing of afferent and efferent information with the central nervous system (CNS). METHODS: Neuro-urological work-up of 11 male patients with chronic prostatic pain was completed. This included a clinical evaluation of pelvic floor function, urodynamic investigation of bladder and urethra function and a cystoscopy to exclude morphological aberrations. A transurethral perisphincteric injection of 200 units botulinum toxin type A (BTX) was followed by a 2- to 4-week visit to evaluate their influence on the neuro-urological symptomatology. RESULTS: All chronic prostatic pain patients suffered from a pathological pelvic floor tenderness, an inability of sufficient conscious pelvic floor control, a urethral hypersensitivity/hyperalgesia and a urethral muscle hyperactivity. Basic parameters of bladder function (capacity, sensitivity, compliance) were normal. The BTX injection was followed by a pelvic floor muscle weakening and a relief of prostatic pain and urethral hypersensitivity/hyperalgesia. A botulinum-related decrease of the functional urethral length, the urethral sphincter closure pressure, the postvoid residual volume and an increase of the peak and average uroflow were objectivated. CONCLUSION: A weakening of the urethral sphincter muscle via blocking acetylcholine release by BTX injection is followed by pain relief and symptom improvement. It can therefore be concluded that a barrage of nociceptive information from the dysfunctional pelvic floor overflood the CNS and induce a changed CNS processing. Interrupting the efferent branch of the disturbed central circle is one opportunity to treat chronic prostatic pain.  相似文献   
77.
78.
0 引言  1 992 - 0 5~ 1 999- 0 5我科收治慢性硬膜下血肿 (CS-DH) 1 6 8例 ,其中 1 6 4例经颅骨钻孔冲洗引流术治疗 ,4例保守治疗 ,结果 1 6 5例治愈 ,3例死亡 .结论 :CSDH的诊断主要依靠 CT检查 ,手术简单 ,防止并发症可改善预后 .1 临床资料 男 1 6 3例 ,女 5例 ,年龄 32~ 79岁 ,平均 5 4岁 .有明确的外伤史 1 4 5例 (86 .3% ) ,原因不明 2 3例(1 3.7% ) ,病程 3wk~ 6 a.头昏、头痛、呕吐 1 1 6例 ,肢体运动障碍 6 8例 ,智力及精神障碍 46例 ,语言障碍 1 0例 ,感觉障碍2 1例 ,排尿障碍 5例 ,癫痫 3例 ,视乳头水肿 92例 ,锥体…  相似文献   
79.
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号